Patent Publication Number: US-2015081152-A1

Title: Apparatus and method for electric braking

Description:
BACKGROUND 
     Embodiments of the disclosure relate generally to an apparatus, a vehicle and a method, and particularly to a power recovering and baking method used in electric tractors, electric forklifts and other vehicles. 
     As a mobile machine, a vehicle is generally designed and specifically configured to transport people or cargo from one place to another. Typical vehicles comprise bicycles, motorcycles, cars/sedans, trucks, haulage motors, tractors, forklifts, buses, ships and air crafts, etc. Traditionally, at least some of vehicles are provided power by engines, e.g. internal combustion engines which burn fuels during operations, for example, diesel, gasoline or natural gas, and convert the power generated by burning fuels into a form of mechanical driving force to drive vehicles moving. However, there are some problems during using diesel , gasoline, natural gas and other resources, which include unrenewable, higher cost and negative impact on environment. Accordingly, developing an electric driving vehicle, for example, a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, a pure electric tractor, a pure electric forklift, etc., gradually becomes a hot research. 
     To improve the range of the above described varieties of vehicles, the electric motor used in a vehicle is generally arranged to operate in multiple modes, for example, one working mode is normal driving mode and another is regenerative braking mode. Specially, in the regenerative braking mode, the electric motor may be arranged to convert a vehicle traveling mechanical power/torque to an electric power, then under the effect of the control system, the energy source (e.g., a rechargeable battery, a super capacitor, etc.) is charged in the vehicle, thus a portion of power is regenerated. Whereas, the present existing technology is that the energy source in a vehicle may not receive all power generated by regenerative braking in some working environments (e.g. adequate electricity). In this situation, other physic braking devices, e.g. mechanical braking device to dissipate mechanical power, are commonly used. Herein results in questions: relative to various state of charges of an energy source, various braking forces need to be supplied to this mechanical braking device, to worsen the vehicle handling. Moreover, in some cases, such as a case of full charge energy source, operating regenerative braking, for instance, neutral position braking or power output device quick braking, may also bring security issues. 
     Accordingly, it is desirable to provide an improved apparatus, vehicle and method to solve at least one of the above-mentioned technical problems or technical requirements of the present existing vehicle. 
     BRIEF DESCRIPTION 
     An apparatus is provided. The apparatus includes an energy source and an electric drive system. The energy source is configured to provide electrical power during discharging mode of operation and receive electrical power during charging mode of operation. The electric drive system includes a converter, at least one motor and a controller. The converter is coupled to the energy source. The converter is configured to convert the electrical power received from the energy source into drive electrical power, and configured to convert regenerative electrical power into charge electrical power for charging the energy source. The motor is coupled to the converter. The motor is configured to receive the drive electrical power provided from the converter and provide mechanical power for driving at least one load in drive mode of operation, and configured to convert mechanical power from the load into the regenerative electrical power in regenerative mode of operation. The controller is coupled to the energy source, converter and the motor. The controller is configured to receive at least one first parameter indicating charging status of the energy source, and configured to receive at least one second parameter indicating operation condition of the at least one motor. The controller is configured to send control signals to the converter, based at least in part on a braking command, the at least one first parameter, and the at least one second parameter to allow the electric drive system to controllably generate loss power resulting from the regenerative power. 
     A vehicle is provided. The vehicle includes an energy source, a converter, at least one motor and a controller. The energy source is configured to provide electrical power during discharging mode of operation and receive electrical power during charging mode of operation. The converter is coupled to the energy source. The converter is configured to convert the electrical power received from the energy source into drive electrical power, and configured to convert regenerative electrical power into charge electrical power for charging the energy source. The motor is coupled to the converter. The motor is configured to receive the drive electrical power provided from the converter and provide mechanical power for driving at least one load, and configured to convert mechanical power from the load into the regenerative electrical power. The controller is coupled to the energy source, converter, and at least one motor. The controller is configured to send first control signals to the converter, based at least in part on a first braking command, to allow a first target braking power corresponding to the first braking command to be solely charged into the energy source. The controller is further configured to send second control signals to the converter, based at least in part on a second braking command, to allow a second target braking power corresponding to the second braking command to be partly charged into the energy source and partly dissipated by the at least one motor. 
     A method for operating a vehicle is provided. The method includes receiving a target braking torque for a motor of the vehicle, generating a target braking power based at least in part on the target braking torque, and distributing the target braking power into a target loss power depending on charging status of an energy storage of the vehicle. The method further includes calculating reference commands based at least in part on the target loss power, and implementing a control for generating control signals based at least in part on the reference commands to allow the target loss power to be dissipated by an electric drive system of the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and aspects of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a schematic block diagram of a vehicle according to an embodiment; 
         FIG. 2  is a schematic block diagram of the vehicle according to another embodiment; 
         FIG. 3  is a schematic block diagram of the vehicle according to another embodiment; 
         FIG. 4  is a schematic block diagram of the vehicle according to another embodiment; 
         FIG. 5  is a schematic block diagram of the vehicle according to another embodiment; 
         FIG. 6  is a control block diagram of a traction motor of a vehicle operating in a regenerative braking mode according to an embodiment; 
         FIG. 7  is a control block diagram of the traction motor of a vehicle operating in the regenerative braking mode according to another embodiment; 
         FIG. 8  is a control block diagram of a power take-off motor of the vehicle operating in a regenerative braking mode according to an embodiment; 
         FIG. 9  is a control block diagram of the power take-off motor of the vehicle operating in the regenerative braking mode according to another embodiment; 
         FIG. 10  is a control block diagram of the power take-off motor of the vehicle operating in the regenerative braking mode according to another embodiment; 
         FIG. 11  is a flow chart of a method for controlling the vehicle according to an embodiment; 
         FIG. 12  is a flow chart of the method for controlling the vehicle according to another embodiment; 
         FIG. 13  is a flow chart of the method for controlling the vehicle according to another embodiment; and 
         FIG. 14  is a flow chart of the method for controlling the vehicle according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Firstly, embodiments of the disclosure relate generally to a vehicle or an improved drive system of a car, or more specifically to a drive system with improved electric braking characteristics used in a vehicle or a car. Specially, in some embodiments, the invention propose a new “electric braking control method” or a new “electric braking power recover distribution method”, which may distribute the energy generated by a motor operating in a regenerative braking mode in accordance with some components&#39; operating mode of a vehicle during operations. For instance, the target braking power may be distributed according to the charging statuses. In some occasions, when the energy source has a low power, whole or part of the power generated by regenerative braking is charged into the energy source. In some other occasions, such as a case of the energy source in a full charge, the target braking power is at least partially distributed into target loss power, which may be the electric drive system generating loss power of a vehicle or a car. For example, in an embodiment, the target loss power may be the loss power of a motor, in a specific embodiment, it may generate a desirable motor control volume based on the target motor loss power, such as a reference current magnitude, furthermore, it also generates a desirable motor current phase delay through a motor torque control circuit, so as to at least operate the motor control based on the reference current magnitude and current phase delay, to control the motor to dissipate partially the target braking power on the motor. In other embodiments, the target loss power may generate loss power through the electric drive system&#39;s convertor or the controller. 
     In some more specific embodiments, this proposed electric braking control method may be operated with a traction motor (TM), namely, when the vehicle or car receive a TM braking command, it may at least partially distribute the TM&#39;s target braking power to TM loss power, according to the energy source&#39;s charge status. 
     In some more specific embodiments, this proposed electric braking control method may be operated with a power take-off (PTO) motor, namely, when the vehicle or car receive a PTO motor braking command, at least part of target braking power of the TM may be distributed to the PTO motor loss power, according to the charge status of the PTO motor. 
     Operating the improved electric braking control method of this invention may obtain varieties of technical effects or technical advantages, one of which is that, the energy generated by the motor in a braking mode can be regenerated maximally to an energy source or an energy storage device of the vehicle so that the vehicle can run longer. Another technical effect or technical advantage is that the vehicle&#39;s drive capability is improved through controlling the motor according to the charge status of the energy source to dissipate the motor braking generating energy. A further technical effect or technical advantage is that it may avoid or reduce the use of mechanical braking devices so as to improve the service life of the mechanical braking devices. A further technical effect or technical advantage is that current dump resistors can be omitted to lower the cost. To the those of ordinary skill in the art to which this disclosure belongs, these and other features and aspects of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings. 
     One or more specific embodiments of this invention may be illustrated in the below. It is firstly that, in these embodiments&#39; specific description, for brief description, the specification couldn&#39;t describe in detail the all characters of actual embodiments. It&#39;s understandable that, in actual operations of any embodiment, just like the process in any engineering project or designing project, to achieve developer&#39;s specific target, or to meet the system relative or commerce relative limitations, various kinds of specific decisions be usually determined, yet which may change from one embodiment to another. Besides, it&#39;s also understandable that, although the efforts of development may be complicated and tedious, to one of ordinary skill of the art which this disclosure is relative to, some changes like design, manufacture or production on the basis of the technical content in this disclosure are conventional technical means, which shouldn&#39;t be understood that the disclosure content is insufficient. 
     Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terms “first”, “second”, and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. “A” or “an” and the like herein do not denote any quantity limit, but only means having at least one. “Or” comprises any one or all of the listed objects. The use of “including,” “comprising”, “having” or “contain” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Although the terms “connected” and “coupled” are often used to describe physical or mechanical connections or couplings, they are not intended to be so restricted and can include electrical connections or couplings, whether direct or indirect. Furthermore, the mentioned “controller” or “control system” may comprise a single component or a combination of a plurality of active components or negative components connected directly or indirectly, such as one or more integrated circuit chips, to supply corresponding detailed functions. 
       FIG. 1  illustrates a schematic block diagram of a vehicle  100  according to an embodiment. Herein the “vehicle” refers to all suitable kinds of machines designed to transport people and/or cargo from one place to another, and/or machines operating one or more auxiliary functions. In one embodiment, the vehicle may be a ground vehicle which moves relative to the road surface, for example, bicycle, motorcycle, car, sedan, truck, van, bus, tractor, electric bus, electric omnibus, tractor, forklift, excavator, crane, garbage truck, trailer, motorcycle, train, subway, etc. The vehicle may also be a vehicle on or in water, e.g., boat, vessel, ship, bow, tanker, etc. 
     In  FIG. 1 , a vehicle  100  includes an electric drive system  101  coupled between an energy source  102  and a load system  103 . The electric drive system  101  is configured to operate unidirectional or bidirectional energy change operations and control operations. More specifically, in an embodiment, the vehicle  100  may work in a drive mode, and the electric drive system  101  is configured to receive an input power supplied by the energy source  102 , convert the input power to a mechanical drive energy or mechanical torque meeting the needs of the load system  103 , and supply the mechanical drive energy or mechanical torque to the load system  103  to drive the load system  103 . In an embodiment, the vehicle  100  may also work in an energy regenerative or braking mode. Specifically, the electric drive system  101  is further configured to convert the mechanical braking power or mechanical torque from the load system  103  to power in other forms. In an embodiment, the other forms of power may be used to charge the energy source  102 , for example, charging a chargeable battery. In other embodiments, the other forms of power may also be used for other purposes, for example, supplying power to a heating device or an air-condition device of the vehicle  100 . 
     In some embodiments, the input power supplied to the electric drive system  101  by the energy source  102  may be direct-current power, alternating current power, or a suitable combination of them. For example, in some embodiments, the energy source  102  may be a battery or a battery pack, but non-limited. The battery or the battery pack mentioned herein may include a lead-acid battery, a nickel cadmium battery, a nickel metal hydride battery, a lithium ion battery, a lithium polymer battery, etc. In other embodiments, the battery or the battery pack includes, for example, hydrogen fuel, bio fuel, gas, fuel cell, flywheel batteries, super capacitors, or combinations of the above, and various other suitable energy supply mechanisms being capable of powering the electric drive system  102 . 
     In some embodiments, the energy source  102  may be an onboard device, which may be integrated with the vehicle  100 . In other embodiments, the energy source  102  may be located outside the vehicle  100 . For example, the vehicle  100  may supply an onboard energy access (not shown) electrically coupled to a power grid or other power equipment. The onboard energy access is configured to convert the power received from the power grid or other power equipment to power with suitable form (e.g. DC power), and supply the converted power to the electric drive system  101 . The onboard energy access may also be configured to charge the energy source  102 , when the storage energy of the energy source  102  is at least partially exhausted. In some embodiments, the energy source  102  may be a combination of the onboard energy source and the onboard energy access, also namely, it may supply power to the electric drive system  101  through the onboard energy source, also supply power to the electric drive system  101  through the onboard energy access, or through their combination. 
     In the illustrated embodiment, the electric power supplied by the energy source  102  is DC power, which is transported to the electric drive system  101  through a circuit connected between the energy source  102  and the electric drive system  101 . In some embodiments, a DC-link (not shown) connects the energy source  102  and the electric drive system  101 , and the DC-link may include one or more capacitors in series and/or in parallel, and is configured to filter the DC power supplied by the energy source  102  and supply the DC power with a certain voltage to the electric drive system  101 . 
     Further referring to  FIG. 1 , in an embodiment, the electric drive system  101  comprises a convertor  104 , a motor  106  and a controller  108 . In the illustrated embodiment, the motor  106  is located inside the electric drive system  101 . In other embodiments, the motor  106  may be arranged outside the electric drive system  101 . Furthermore, in some embodiments, the electric drive system  101  may include other elements, like the DC-link mentioned above. 
     In an embodiment, the convertor  104  is configured to operate bidirectional energy change operations. More specifically, when the vehicle  100  operates in a first working mode, such as a drive mode, the convertor  104  is configured to convert a first power  122  from the energy source  102  (e.g. DC power) to a second power  124  (e.g. AC power) supplied to a motor  106 . In other embodiments, the convertor  104  may be configured to receive the DC power converted by the DC-DC converter arranged between the energy source  102  and the converter  104 . The motor  106  supplies a mechanical power or mechanical torque to the load system  103  in the effect of the second power  124 . In a specific embodiment, the motor  106  may be a three-phase AC motor, or more specifically a brushless DC motor. In other embodiments, the motor  106  may be any other types of motors, like a permanent magnet synchronous motor, etc. In the illustrated embodiment, the motor  106  and the load system  103  are coupled through a transmission system  108  (e.g. gear case) which could adjust the mechanical output torque or velocity of the motor  106 . In some other embodiments, the transmission system  108  may be excluded. In this illustrated embodiment, the load system  103  includes a first drive wheel  112  and a second drive wheel  114  operating in the effect of the mechanical energy or mechanical torque supplied by the motor  106  or the transmission system  108 , to drive the vehicle  100  to take specific actions (e.g. forward, backward, turn, etc.). In other embodiments, the load system  103  may include one or more than two drive wheels, and in some other embodiments, the load system  103  may also include other types of load devices. 
     Sequentially shown as  FIG. 1 , in an embodiment, when the vehicle  100  operates in a second working mode, such as a regenerative braking mode, the convertor  104  is also configured to convert the first power  124  (e.g. three-phase AC power) from the motor  106  to a second power  122  (e.g. DC power). The first power  124  is acquired through converting the mechanical energy or mechanical torque of the motor  106 , the second power  122  is provided to the energy source  102 , e.g. a chargeable battery or a super capacitor to be charged, so as to regenerate a portion of energy for the following drive mode operations. Obviously, as above described, the second power  122  may be configured to power other devices inside the vehicle  100  (e.g. powering a heating device or an air-conditioning device, etc.), and/or power the other devices outside the vehicle  100 , (e.g. a power network). 
     The convertor  104  mentioned herein may be any suitable type of convertors, such as an inverter with full-bridge topology structure, etc. The convertor  104  may include multiple switch devices which are turned on and/or off in the effect of the control signal  134  of the controller  116  to convert electric. The switch devices mentioned herein may be suitable varieties of switch devices based on semiconductors including but not limited to, bipolar transistor, metal oxide field effect transistor, turn off thyristor, insulated gate bipolar transistor, gate converter thyristor and devices based on silicon carbide, etc. 
     Sequentially shown as  FIG. 1 , in an embodiment, the controller  116  is configured receive at least one first parameter signal  128  relative to the energy source  102 , and at least one second parameter signal  132  relative to the motor  106 . In an embodiment, the first parameter signal  128  may denote the state-of-charge of the energy source  102 , and may be measured by one or more sensors (not shown). In other embodiments, the first parameter signal  128  reflecting the state-of-charge of this energy source  102  may be supplied by the energy management system (EMS) relative to the energy source  102 . In an embodiment, the second parameter signal  132  may be a torque and/or velocity and so on, which may also be measured by one or more sensors (not shown). Besides, the controller  116  is configured to receive one or more command signals  126 , such as a braking command. Specially, the controller  116  is configured, at least based on the first parameter signal  128 , the second parameter signal  132  and the command signal  126 , to operate the proposed new electric-brake control algorithm  118  and send the control signal  134  to the convertor  104  to distribute the energy generated by the motor  106  in the regenerative braking mode. More specifically, operating the electric-brake control algorithm  118  based on various input command signals and the first, second parameter signals  128 ,  132 , etc. may result in different distributions of the regenerative braking power. For instance, in a condition, when the first input command  126  instructs the motor  106  to generate a relative smaller first braking power and the energy source  102  has lower power or can receive much charge power, the regenerative braking power from the energy source  102  is regenerated back to the energy source  102 . In another condition, when the first input command  126  instructs the motor  106  to generate a second braking power which is bigger than the first braking power and the state of charge of the energy source  102  indicates the energy source  102  cannot receive all the regenerative braking power generated by the motor  102 , the convertor  104  is controlled to output parameters of the power  124  to the motor  106 , such as adjusting the current magnitude and postponing current phase, to make the motor  106  to generate self-controllably some energy, thus achieving desirable braking effect. That is to say, a portion of loss power acquired by the regenerative braking is dissipated through controlling the motor  106 , to make the state of charge of the energy source  102  has no impact on the braking torque or braking force, thus offering the person controlling the vehicle a better drive capability. The detailed embodiments about the electric-brake control algorithm  118  will be described with  FIGS. 6-12  below. 
     In other embodiments, the controller  116  may also receive parameters of other devices, e.g., receive parameters relative to the convertor  104  and operate the electric-brake control algorithm  118  based on the received parameters to distribute reasonably the power generated by the motor  106  in braking. More specifically, in an alternative embodiment, the controller  116  may receive various parameters for the convertor  104  including current, voltage, and/or temperature parameters to make the power generated by the motor  106  in braking to be dissipated in the convertor  104  in some embodiments. More specifically speaking, when the state of charge of the energy source  102  indicates the energy source  102  does not have enough capacity to receive all the regenerative braking power generated by the motor  102 , the convertor  104  is controlled, for instance, a part of switch devices of the convertor  104  is controlled to generate controllable conductive dump, to dissipate a portion of the braking power. In some other embodiments, part of the braking power generated by the motor  106  is dissipated in the controller  116  through the controller  116  itself 
     The controller  116  mentioned herein may include varieties of programmable circuits or devices including Digital Signal Processor (DSP), Field Programmable Gate Array (FPGA), Programmable Logic Controller (PLC) and Application Specific Integrated Circuit (ASIC). The electric-brake control algorithm  118  herein may be operated through software, hardware, or a combination thereof 
       FIG. 2  illustrates a schematic block diagram of a vehicle  110  according to another embodiment. The vehicle  110  shown in  FIG. 2  is substantially similar to the vehicle  100  in  FIG. 1 , such as, the vehicle  110  also includes an energy source  102  and an electric drive system  101 , and the electric drive system  101  also includes a convertor  104 , a motor  106 , and the controller  116 . Therefore, the devices symbolized in the same symbols shown in the embodiments of  FIG. 2  will not be described detailed. Specifically, in the embodiment of  FIG. 2 , the vehicle  110  may also include one or more mechanical braking devices, for example, the first braking device  134  and the second braking device  136 . The first mechanical barking device  134  is coupled to the first drive wheel  112  through various current structures, so as to supply braking force to the mechanical energy of the second drive wheel  114 , to decelerate or stop operating. 
     Sequentially shown in  FIG. 2 , the controller  116  is configured, at least based on a first command  126 , first and second parameter signals  128 ,  132 , to operate the electric-brake control algorithm  119  to distribute the braking power generated by the motor  106  in the regenerative braking mode. More specifically speaking, operating the electric-brake control algorithm  119  according to various input commands  126  and the first, second parameter signals  128 ,  132 , etc. may result in different distribution of the regenerative braking power. For instance, in a condition, when the first input command  126  instructs the motor  106  to generate a relative smaller first braking power and the energy source  102  has lower power or can receive much charge power, the regenerative braking power from the energy source  102  is regenerated back to the energy source  102 . In another condition, when the first input command  126  instructs the motor  106  to generate a second braking power which is bigger than the first braking power and the state of charge of the energy source  102  indicates the energy source  102  do not have capacity to receive all the regenerative braking power generated by the motor  102 , the convertor  104  is controlled to output parameters of the power  124  to the motor  106 , such as adjusting the current magnitude and postponing current phase, to make the motor  106  to generate self-controllably some energy, thus achieving desirable braking effect. That is to say, a portion of loss power acquired by the regenerative braking is dissipated through controlling the motor  106 , to make the state of charge of the energy source  102  has no impact on the braking torque or braking force, thus offering the person controlling the vehicle a better drive capability. In another case, when the first input command  126  instructs the motor  106  to generate a third braking power which is bigger than the second braking power and the state of charge of this energy source  102  indicates the energy source  102  do not have capacity to receive all the regenerative braking power generated by the motor  102 , part of the regenerative braking power from the motor  106  may be controlled to be dissipated in the first and/or second mechanical braking devices  134 ,  136 , and part of the rest regenerative braking power is configure to charge the energy source  102 , yet remain regenerative braking power is dissipated in the motor  106 . 
     Similarly, when the controller  116  is operating electric-brake control algorithm  119 , at least a portion of the braking power is dissipated in the convertor  104  and/or the controller  116 . 
       FIG. 3  is a schematic block diagram of a vehicle  120  according to another embodiment. The vehicle  120  includes an energy source  102 , a load system  103  and an electric drive system  101  coupled therebetween. In a specific embodiment, the vehicle  120  may be implemented in an E-tractor or an E-forklift or other various suitable devices not only running but also operating miscellaneous functions. Similarly, the electric drive system  101  is also configured to have an improved regenerative braking power distribution mechanism to distribute reasonably the braking power of the motor in the regenerative braking mode according to various parameter signals (e.g. the state of charge of the energy source  102 ) and/or command signals (e.g. target braking torques, etc.), etc. 
     In the embodiment shown in  FIG. 3 , the electric drive system  101  includes a TM converter  104 , a TM  106 , a PTO convertor and a controller  116 . In an embodiment, one or both of the TM convertor  104  and the PTO convertor  144  are configured to operate bidirectional energy exchange operations. 
     More specifically, when the vehicle  100  operates in a first working mode, such as a drive mode, the TM convertor  104  may be configured to convert the first power  122  from the energy source  102  (e.g. DC power) to a second power  124  (e.g. AC power) supplied to a TM  106 . In other embodiments, the convertor  104  may be configured to receive the DC power converted by the DC-DC converter arranged between the energy source  102  and the TM converter  104 . The TM  106  supplies a mechanical power or mechanical torque to a load system  103  in the effect of the second power  124 . In a specific embodiment, the TM  106  may be a three-phase AC motor, or more specifically a brushless DC motor. In other embodiments, the TM  106  may be any other type of motors, like a permanent magnet synchronous motor, etc. In this illustrated embodiment, the motor  106  and the load system  103  are coupled through a drive system  108  (e.g. gear case), which could adjust the mechanical output torque or velocity of a motor  106 . In some other embodiments, the drive system  108  may be excluded. In the illustrated embodiment, the load system  103  includes the first load, such as, a first drive wheel  112  and a second drive wheel  114 , operating in the effect of the mechanical energy or mechanical torque supplied by the motor  106  or the vehicle  108 , to drive the vehicle  100  to take specific actions like forward and backward etc. In other embodiments, the load system  103  may include one or more than two drive wheels. 
     In an embodiment, when operating in the first working mode or the drive mode, the PTO convertor  144  and the PTO motor  148  may not work temporarily to stop supplying output mechanical energy or mechanical torque to the PTO device  152 . For instance, the electric tractor returns home from a farm after finishing ploughing the farmland. In another embodiment, the PTO convertor  144  and the PTO motor  148  may work at the same time with the TM convertor  104  and the TM  106 , like the E-tractor ploughing the farmland rotationally while traveling. In the first working mode, when the PTO motor  148  supplies take-off power, the PTO convertor  144  is configured to convert the first electric power  141  (e.g. DC power) of the energy source  102  to a second power  146  (e.g. AC power), and supply the second power  146  to the PTO motor  148 . In other embodiments, the PTO convertor  144  may be also configured to receive the DC power converted by the DC-DC converter arranged between the energy source  102  and the converter  104 . In other embodiments, the PTO convertor  144  and the traction convertor  104  may be configured to receive the input power from the respectively set energy sources, i.e., the traction convertor  104  receives the power from the first power source, and the PTO convertor  144  receives the power from the second power source. The PTO motor  148  in effect of the second power  146  supplies mechanical energy or mechanical torque to the PTO device  152  in the load  103 . The operating functions of the PTO devices  152 , includes but is limited to, dressing plants, ploughing the land, listing materials, shoveling material, excavating materials and pouring materials, etc. In a specific embodiment, the PTO motor  148  may be a three-phase AC motor, or more specifically a brushless DC motor. In other embodiments, the PTO motor  106  may also be other types of motors, like a permanent magnet synchronous motor. In this schematic embodiment, the PTO motor  148  is coupled directly to the PTO device  152 , in other embodiments, the PTO motor  148  and the PTO device  152  are coupled through a drive system  108  (e.g. gear case), which could adjust the mechanical output torque or velocity of a power taker-off motor  148 . 
     Sequentially shown as  FIG. 3 , in an embodiment, when the vehicle  100  operates in a second working mode, such as a regenerative braking mode, the PTO convertor  144  nay also be configured to convert the first power  146  (e.g. three-phase AC power) from the PTO motor  106  to a second power  141  (e.g. DC power), wherein the first power  146  is acquired through converting the mechanical energy or mechanical torque of the PTO motor  148 , and the first power  146  is provided to the energy source  102 , e.g. a chargeable battery or a super capacitor, etc. to charge it, so as to regenerate some energy for the following drive mode operations or supplying other assistance PTO. Obviously, as above described, the second power  122  may be configured to power other devices inside the vehicle  100  (e.g. powering a heating device or an air-conditioning device, etc.), and/or power the other devices outside the vehicle  100 , e.g. a power network, etc. 
     In an embodiment, when the vehicle  120  operates in a second working mode, such as a regenerative braking mode, the convertor  104  nay also be configured to convert the first power  124  (e.g. three-phase AC power) from the motor  106  to a second power  122 (e.g. DC power), wherein, the second power  141  is provided to the energy source  102 , e.g. a chargeable battery or a super capacitor, etc. to charge it, thus to regenerate a portion of energy to be used in the following drive mode operations, or to supply other assistance PTO. Obviously, as above described, the second power  141  may be configured to power other devices inside the vehicle  100 (e.g. powering a heating device or an air-conditioning device, etc.), and/or power the other devices outside the vehicle  100 , e.g. a power network. 
     Sequentially shown as  FIG. 3 , in an embodiment, the controller  116  is configured receive at least one first parameter signal  128  relative to the energy source  102 , at least one second parameter signal  132  relative to the TM  106 , and at least one third parameter signal  154  relative to the PTO motor  148 . In an embodiment, the first parameter signal  128  may denote the state-of-charge of the energy source  102 , and may be measured with one or more sensors (not shown). In other embodiments, the first parameter signal  128  reflecting the state-of-charge of this energy source  102  may be supplied by the energy management system (EMS) relative to the energy source  102 . In an embodiment, the second parameter signal  132  may be a torque and/or velocity and so on, which may also be measured by one or more sensors (not shown). Besides, the controller  116  is still configured to receive at least the first command signal  126  and the second command signal  138 . Specially, the first command signal  126  may be a TM braking command, and the second command signal  138  may be a PTO motor braking command. 
     In an embodiment, the controller  116  is configured, at least based on a first command  126 , first and second parameter signals  128 ,  132 , to operate the traction electric-brake control algorithm  121  and send control signals  134  to the TM (TM) converter  104  to distribute the braking power generated by the motor  106  in the regenerative braking mode. More specifically speaking, operating the traction electric-brake control algorithm  121  according to various input commands  126  and the first, second parameter signals  128 ,  132 , etc. may result in different distribution of the regenerative braking power. For instance, in a condition, when the first input command  126  instructs the TM  106  to generate a relative smaller first braking power and the energy source  102  has lower power or can receive much charge power, the regenerative braking power from the energy source  102  is regenerated back to the energy source  102 . In another condition, when the first input command  126  instructs the TM  106  to generate a second braking power which is bigger than the first braking power and the state of charge of the energy source  102  indicates the energy source  102  do not have capacity to receive all the regenerative braking power generated by the motor  102 , the convertor  104  is controlled to output parameters of the power  124  to the TM  106 , such as adjusting the current magnitude and postponing current phase, to make the TM  106  to generate self-controllably some energy, thus achieving desirable braking effect. That is to say, a portion of loss power acquired by the regenerative braking is dissipated through controlling the TM  106 , to make the state of charge of the energy source  102  has no impact on the braking torque or braking force, thus offering the person controlling the vehicle a better drive capability. 
     In an embodiment, the controller  116  is configured, at least based on the first parameter signal  128 , the third parameter signal  154 , and the second command signal  138 , etc., to operate the PTO electric-brake control algorithm  123 , and to send a control signal  142  to the PTO convertor  144 , thus to distribute the braking power generated by the PTO motor  148  in the regenerative braking mode. More specifically speaking, operating the PTO electric-brake control algorithm  123  according to various second input commands  126  and the first, third parameter signals  128 ,  154 , etc. may result in different distributions of the regenerative braking power. For instance, in a case, when the second input command  138  instructs the PTO motor  148  to generate relative smaller first braking power and the energy source  102  is in low power or may receive much charge power, all the regenerative braking power from the PTO motor  148  may be regenerated back to the energy source  102 . In another case, when the second input command  138  instructs the PTO motor  148  to generate a second braking power which is bigger than the first braking power and the state of charge of this energy source  102  indicates the energy source  102  does not have capacity to receive all the regenerative braking power from the PTO motor  148 , the convertor  104  is controlled to output parameters of the power  146  to the PTO motor  148 , such as adjusting the current magnitude or postponing current phase, etc., to make the PTO motor  148  to generate self-controllably some energy, thus achieving desirable braking effect. 
     Similarly, when the controller  116  is operating the TM electric-brake control algorithm  121  and the PTO electric-brake control algorithm  123 , at least part of the braking energy from the TM  106  and the PTO motor  148  is dissipated in the traction convertor  104 , the PTO convertor  144  and/or the controller  116 . 
       FIG. 4  is a schematic block diagram of the vehicle  130  according to another embodiment. The vehicle  130  shown in  FIG. 3  is substantially similar to the vehicle  120  in  FIG. 3 , such as, the vehicle  130  also includes an energy source  102  and an electric drive system  101 , and the electric drive system  101  also includes a traction convertor  104 , a TM  106 , PTO convertor  144 , PTO motor  148  and the controller  116 . Therefore, the devices symbolized in the same symbols shown in the embodiments of  FIG. 4  will not be described detailed. Specifically, in the embodiment of  FIG. 4 , the vehicle  130  also includes one or more dump resistors or brake resistors  156 . The dump resistor  156  is coupled to the PTO device  152  through various known structures, to dissipate the PTO motor  148  braking generating energy, so as to decelerate or stop operating. 
     In an embodiment, the controller  116  is configured, at least based on the first parameter signal  128 , the third parameter signal  154 , and the second command signal  138 , etc. to operate the PTO motor electric-brake control algorithm  125 , and to send a control signal  142  to this PTO convertor  144 , thus to distribute reasonably the braking power generated by the PTO motor  148  in a regenerative braking mode. In another case, when the second input command  138  instructs the PTO motor  148  to generate a third braking power (larger than the mentioned second braking power in conjunction with  FIG. 3 ), and the state of charge of the energy source  102  indicates the energy source  102  does not have capacity to receive all the regenerative braking power of the PTO motor  148 , a part of the regenerative braking power from the PTO motor  148  is controlled to dump in a dump resistor or a braking resistor  156 , a portion of the rest regenerative braking power is used to charge the energy source  102 , yet remain portion is dissipated in the PTO motor  148 . 
       FIG. 5  is a schematic block diagram of the vehicle  140  according to another embodiment. The vehicle  140  shown in  FIG. 5  is substantially similar to the vehicles  120  and  130  in FIG . 3  and  FIG. 4 , such as, the vehicle  140  also includes an energy source  102  and an electric drive system  101 , and the electric drive system  101  also includes a traction convertor  106 , a PTO motor  148 , and the controller  116 . Therefore, the devices symbolized in the same symbols shown in the embodiments of  FIG. 5  will not be described detailed. In the embodiment of  FIG. 5 , the electric drive system  101  also includes an integrated convertor  156 , electrically coupled to an energy source  102 , a TM  106  and a PTO motor  148 , and it may operate bidirectional energy convert operations in effect of the control signals  134  from the controller  116 , i.e., the first power  122  of the energy source  102  is converted to a second power  124  for the TM  106  and a third power  146  for PTO motor  148 . In a regenerative braking mode, the second power  124  from the TM  106  and the third power  146  from the PTO motor  148  are converted to a first power  122  to charge the energy source  102 . Specific details about the integrated convertor  156  may refer to a China patent application transferred to the joint applicators with the application date of Mar. 15, 2013 and the application number of CN20130084090.2, the full text of which is referred herein as reference. 
     In the embodiment shown in  FIG. 5 , the controller  116  is configured, at least based on the first parameter signal  128 , the second parameter signal  132  and the first command signal  126 , to operate the electric-brake control algorithm  121 , and to send a control signal  134  to the integrated convertor  156 , thus to distribute the braking power generated by the TM  106  in the regenerative braking mode. More specifically speaking, operating the electric-brake control algorithm  121  according to various input commands  126  and the first, second parameter signals  128 ,  132 , etc. may result in different distributions of the regenerative braking power. Specially, in some cases, when the PTO motor  148  works normally to control the PTO device  152  to operate some tasks, the controller  116  sends the control signals  134  to the integrated convertor  156  to adjust parameters of the second power  124  and the third power  146 , such as the current magnitude and current phase delay, thus a portion of the energy generated by the TM  106  in braking is dissipated in the TM  106 , yet the other portion of the energy is dissipated in the PTO motor  148 . In some other embodiments, a portion of the energy generated by the TM  106  in braking is dissipated in the mechanical braking devices  135  and  136 . 
     In the embodiment shown in  FIG. 5 , the controller  116  is configured, at least based on the first parameter signal  128 , the second parameter signal  132  and the first command signal  128 , to operate the PTO electric-brake control algorithm  121 , and to send the control signal  134  to this integrated convertor  156 , thus to distribute the braking power generated by the PTO motor  106  in a regenerative braking mode. More specifically speaking, operating the electric-brake control algorithm  125  according to various input commands  138  and the first, second parameter signals  128 ,  132 , etc. may result in different distributions of the regenerative braking power. Specially, in some cases, when the TM  148  works normally to output mechanical torques to the loads  112  and  114  and the energy source  102  could not receive all energy from the PTO motor  148  in braking, the controller  116  may send the control signals  134  to the integrated convertor  156  to adjust the parameters of the second power  124  and the third power  146 , such as the current magnitude and current phase delay, thus a portion of the energy generated by the PTO motor  148  in braking is dissipated in the TM  106 , yet the other portion is dissipated in the PTO motor  148 . In some other embodiments, a portion of the energy generated by the PTO motor  148  in braking is dissipated in the dump resistor  156 . 
       FIG. 6  is a control block diagram of the traction electric-brake control algorithm  210  distributing energy of the TM of a vehicle in a regenerative braking mode according to an embodiment. The traction electric-brake control algorithm  210  may be operated through software, or through hardware, or through a combination of software and hardware. 
     Shown in  FIG. 6 , the traction electric-brake control algorithm  210  includes a TM braking power calculation unit  204 , a pre-set power distribution unit  212 , a charging energy calculation unit  222 , a TM target dump calculation unit  216 , a current reference calculation unit  228 , a TM control unit  242  and a traction torque regulation unit  236 . 
     The TM braking power calculation unit  204  is configured to receive the TM target braking torque signals  202  and the TM feedback velocity  206 , and to calculate the TM target braking power  208  of the TM based on the below formula: E=T×V, where E is the TM target braking power, T is the TM target braking torque, and V is the TM actual velocity. 
     The pre-set power distribution unit  212  receives the TM target braking power  208  calculated by the TM braking power calculation unit  204 , and distributes the TM target braking power  208  in accordance with pre-set rules. In an embodiment, the pre-set power distribution unit  212  is configured to preferentially regenerate the TM target braking power  208  back to the energy source  102 , also i.e., when the energy source  102  can receive all the TM target braking power  208 , the pre-set power distribution unit  212  may set a target mechanical braking power  246  distributed to the mechanical braking device  248  as zero, and send all of a sub target braking power  214  generated in the distribution back to the energy source  102 . In an embodiment, when the state of charge of the energy source  102  demonstrates the energy source  102  do not have enough capacity to receive all the target braking power  208 , the pre-set power distribution unit  212  regenerates the target braking power  208  to the energy source  102  as much as possible, and then dissipates rest of the TM target braking power  208  in the TM  106  and the mechanical braking device  248 . In some embodiments, if the rest power after the TM target braking power  208  is regenerated to the energy source  102  is smaller than the maximum dumping power generated by the TM  106 , also i.e., when the TM  106  is able to bear the rest energy after the TM target braking power  208  charging the energy source  102 , the pre-set power distribution unit  212  may set the target mechanical braking power  246  distributed to the mechanical braking device  248  as zero. 
     The TM target dump calculation unit  216  is configured to obtain the TM target loss power  226  through a subtraction between the sub target braking power  214  from the pre-set power distribution unit  212  and the energy source target charging power (or energy source chargeable power)  224 . In an embodiment, the energy source target charging power (or energy source chargeable power)  224  is calculated by the charging energy calculation unit  222  according to the signal  218  denoting the state of charge of the energy source  102 . The TM target loss power  226  is employed by the reference current calculation unit  228  to calculate a reference current magnitude signal  232 . The reference current magnitude signal  232  indicates the desirable magnitude value of the current from the TM convertor  104  to the TM  106 . The reference current magnitude signal  232  is provided to the TM control unit  242 . In an embodiment, the TM control unit  242  generates a control signal  244  at least based on the reference current magnitude  232  and the current phase delay command  238  from the traction torque regulation unit  236  to control the TM convertor  104  to change or adjust the parameters of the power output from the TM convertor  104  to the TM  106 , thus the regenerative braking power of the TM  106  is distributed reasonably. 
     In the embodiment shown in  FIG. 6 , the current phase delay command  238  may be generated by the traction torque regulation unit  236  according to the TM feedback torque signal  234  and the reference braking torque signal  217 . In the embodiment of  FIG. 6 , the TM electric-brake control algorithm  210  still includes a reference traction torque calculation unit  215 . The reference traction torque calculation unit  215  may divide the sub-target braking power  214  and the TM feedback velocity  206  to acquire a reference braking torque signal  217 . 
       FIG. 7  is a control block diagram of the traction electric-brake control algorithm  210  distributing energy of the TM of a vehicle in a regenerative braking mode according to another embodiment. The TM electric-brake algorithm  220  shown in  FIG. 7  has a basic structure similar to the TM electric-brake algorithm  210  shown in  FIG. 6 , thus, the components or modules symbolized in a same component symbol are not described in detail herein. 
     In the embodiment of  FIG. 7 , the TM electric-brake algorithm  220  still includes a magnitude limit device  252  and a summation device  256 . The magnitude limit device  252  is coupled between the TM target dump calculation unit  216  and the reference current calculation unit  228 . The magnitude limit unit  252  is configured to limit the target loss power  226  based on the maximum and the minimum motor loss value relative to the TM  106 , and to supply a limited target loss power value  254  to the reference current calculation unit  228 . In an embodiment, the summation unit  256  is configured to do a subtraction between the non-limited target loss power  226  and limited target loss power  254  to acquire an power deviation signal or an extra target loss power  258 . When the power deviation signal  258  is positive, it means that the target loss power  226  is larger than the maximum loss power generated by the TM  106 , therefore, in an embodiment, the power deviation signal  258  is configured to control the mechanical braking device  248  to generate a braking force so that the extra target loss power is dissipated by the mechanical braking device  248 . 
     Furthermore, in the embodiment shown in  FIG. 7 , the TM electric-brake algorithm  220  also includes a summation unit  213  and a reference traction torque calculation unit  215 . The summation unit  213  adds the energy source target charge energy (or energy source chargeable energy)  224  from the charging power calculation unit  222  and the limited target loss power  254 , so as to get a hybrid energy value  211 . The reference traction torque calculation unit  215  is configured to divide the hybrid power value  211  with the TM feedback velocity  206 , thus to obtain a TM reference torque  217 . The TM reference torque  217  and the feedback traction torque signal  234  are used by the traction torque regulation unit  236  to produce a current phase delay command  238 . 
       FIG. 8  is a control block diagram of the PTO electric-brake control algorithm  310  distributing the regenerative braking power from a PTO motor of a vehicle in the regenerative braking mode according to an embodiment. The PTO electric-brake control algorithm  310  may be achieved through software, through hardware, or through a combination of software and software. 
     Shown as  FIG. 8 , the PTO electric-brake control algorithm  310  includes a PTO braking power calculation unit  304 , a charging power calculation unit  222 , a PTO target dump calculation unit  312 , a current reference calculation unit  316 , a PTO motor control unit  328  and a PTO torque regulation unit  324 . 
     The PTO braking power calculation unit  304  is configured to receive a PTO target braking torque signal  302  and a PTO feedback velocity signal  306 , and calculate the TM target braking power  308  based on the following formula: E=T×V, where E is the PTO target braking power, T is the PTO target braking torque, and V is the PTO actual velocity. 
     In an embodiment, the PTO target dump calculation unit  312  is configured to acquire the PTO target loss power  314  through subtraction between the PTO target braking power  308  from the PTO braking power calculation unit  304  and the energy source target charge power (or energy source chargeable power)  224 . In an embodiment, the energy source target charge power (or energy source chargeable power)  224  is calculated by the charging power calculation unit  222  according to the signal  218  denoting the state of charge of the energy source  102 . The PTO target loss power  314  is employed by the current reference calculation unit  316  to calculate a reference current magnitude signal  318  instructing the desirable magnitude value of the current from the PTO convertor  144  to the PTO motor  106 . The reference current magnitude signal  318  is provided to the PTO motor control unit  328 . In an embodiment, the PTO motor control unit  328  generates a control signal  322  at least based on the reference current magnitude  318  and the current phase delay command  326  from the PTO torque regulation unit  324  to control the PTO convertor  144  to change or adjust the parameters of the power transferred to the PTO motor  148 , thus the regenerative braking power of the PTO motor  148  is distributed reasonably. 
       FIG. 9  is a control block diagram of the PTO electric-brake control algorithm  320  distributing the regenerative braking power from a PTO motor of a vehicle in the regenerative braking mode according to another embodiment. The PTO electric-brake control algorithm  320  shown in FIG . 9  has a basic structure similar to the PTO electric-brake control algorithm  310  in  FIG. 8 , therefore the elements or modules symbolized with a same element symbol in this embodiment are not described in detail. 
     In the embodiment of  FIG. 9 , the PTO electric-brake control algorithm  320  further includes a pre-set power distribution unit  334 . The pre-set power distribution unit  334  receives the PTO target braking power  308  calculated by the PTO braking power calculation unit  304 , and distributes the PTO target braking power  308  in accordance with pre-set rules. In an embodiment, the pre-set power distribution unit  334  is configured to preferentially regenerate the PTO target braking power  308  back to the energy source  102 , also i.e., when the energy source  102  can receive all the PTO target braking power  308 , the pre-set power distribution unit  334  sets the target dumping power  338  distributed to a dump or braking resistor  342  as zero, and send all the sub target braking power  336  generated in the distribution back to the energy source  102 . In an embodiment, when the state of charge of the energy source  102  demonstrates the energy source  102  do not have enough capacity to receive the whole TM target braking power  308 , the pre-set power distribution unit  334  dissipates the rest power in the PTO motor  148  and the dump or braking resistor  342  after regenerating the PTO target braking power  308  to the energy source  102 . In some embodiments, if the rest power after the PTO target braking power  308  is regenerated to the energy source  102  is smaller than the maximum loss power generated by the PTO motor  148 , also i.e., when the PTO motor  148  is able to bear the rest energy after the PTO target braking power  308  charging the energy source  102 , the pre-set power distribution unit  334  sets the target dumping power  338  distributed to the dump or braking resistor  342  as zero. 
     Furthermore, in the embodiment shown in  FIG. 9 , the PTO electric-brake control algorithm  320  also includes a reference PTO torque calculation unit  315 . The reference PTO torque calculation unit  315  is configured to divide the sub target braking power  336  with the PTO feedback velocity  306 , thus to obtain a PTO reference torque  317 . The PTO torque regulation unit  324  calculates a current phase delay command  326  according to the PTO reference torque  317  and the PTO feedback torque signal  322 . 
       FIG. 10  is a control block diagram of the PTO electric-brake control algorithm  330  distributing the regenerative braking power from a PTO motor of a vehicle in the regenerative braking mode according to another embodiment. The PTO electric-brake control algorithm  330  shown in FIG . 10  has a basic structure similar to the PTO electric-brake control algorithm  320  in  FIG. 9 , therefore, the elements or modules symbolized with a same element symbol in this embodiment are not described in detail. 
     In the embodiment of  FIG. 10 , the PTO electric-brake control algorithm  320  still includes a magnitude limit device  346  and a summation unit  352 . The magnitude limit device  346  is coupled between the PTO target loss power calculation unit  312  and the reference current calculation unit  316 . The magnitude limit unit  346  is configured in accordance with the maximum and the minimum motor loss value relative to the PTO motor  148  to limit the target loss power  314 , and to supply a limited target loss power  348  to the current reference calculation unit  316 . In an embodiment, the summation unit  352  is configured to acquire a power deviation signal or an extra target dumping power  358  through subtraction between the non-limited target loss power  314  and limited target loss power  348 . When the power deviation signal  358  is positive, it means that the target loss power  314  is larger than the maximum loss power generated by the TM  148 , therefore, in an embodiment, the power deviation signal  358  is employed to control the braking resistor  342  to generate a braking force, and the extra target loss power is dissipated by the braking resistor  342 . 
     Furthermore, in the embodiment shown in  FIG. 10 , the PTO electric-brake control algorithm  330  also includes a summation unit  354  and a reference PTO torque calculation unit  315 . The summation unit  354  is configured to add the energy source target charge power (or energy source chargeable power)  224  of the charging power calculation unit  222  to the limited target loss power  348 , so as to get a hybrid power  356 . The reference PTO torque calculation unit  315  is configured to divide the hybrid power  356  with the PTO motor feedback velocity signal  306 , thus to obtain a PTO reference torque  317 . The PTO reference torque  317  and the PTO feedback torque  322  are used by the PTO torque regulation unit  324  to produce a current phase delay command  326 . 
       FIGS. 11 to 14  are flowcharts of the methods  1100 ,  1200 ,  1300  and  1400  for controlling the vehicles. To be understood, the methods  1300 ,  1400  herein are at least able to be operated by the vehicles  100 ,  110 ,  120 ,  130  and  140  mentioned above. To describe these flowcharts conveniently, every step of the methods  1100 ,  1200 ,  1300  and  1400  in the below detailed description, will be introduced mainly in conjunction with one or more elements of the vehicle  120 , however, to one of ordinary skill in the art which belongs to, every step of these methods  1100 ,  1200 ,  1300   1400  is not limited to one or more parts herein, in addition, also to be noticed, at least a portion of steps of the methods  1100 ,  1200 ,  1300 ,  1400  may be programmed to program commands or computer software, and saved in a storage medium readable to a computer or a processor. When the program commands are operated by a computer or a processor, it could achieve every step as the workflow chart methods  1100 ,  1200 ,  1300  and  1400 . Understandably, computer readable mediums may include the volatile and nonvolatile, movable and non-movable mediums achieved in any method or technology. More specifically, the computer readable medium includes but is not limited to a random access memory, read only memory, electrically erasable read-only memory, flash memory, or other memory technology, CD-ROM, digital optical disk storage, or other forms of optical storage, magnetic cassettes, magnetic tape, disk, or other forms of magnetic memory, and any other form of storage mediums configured to store reservation information able to be accessed by a command operating system. 
     Referring to  FIG. 13 , the method  1100  includes a step  1102  where the TM target braking torque is received. In some embodiments, the controller  116  (shown in  FIG. 3 ) receives a first command  126 , which instructs the braking torque desirable to be obtained corresponding to the TM  106 , as well, in different working conditions, the first command  126  may have different values, such as, when the vehicle  120  operating in a high speed, it may input a braking torque command with a comparatively larger value; yet the vehicle  120  in a low speed, it may input a braking torque command with a relatively smaller value. 
     In an embodiment, the method  1100  still includes a step  1104  where the TM target braking power is generated at least based on the TM target braking torque from the step  1102 . For instance, in an embodiment, when the controller  116  is operating the TM electric-brake control algorithm  118 , the TM braking power calculation unit  204  in  FIG. 6  may be employed to calculate the TM target braking power based on the TM target braking torque  202  and the TM feedback velocity  206 . 
     In an embodiment, the method  1100  still includes a step  1106  where the TM target braking power calculated in the step  1104  is distributed according to pre-set rules. In an embodiment, when operating the step  1106 , the energy is distributed according to the state of charge of the energy source  102 , such as, when the energy source  102  may receive all the TM target braking power, meanwhile, the TM may transfer all the target braking power generated according to the target braking torque to the energy source  102 . In another embodiment, when operating the step  1106 , it may also distribute the energy according to the loss power produced by the TM  148 . For example, when the state of charge of the energy source  102  denotes the energy source  102  do not have enough capacity to receive all the TM target braking power  208 , and the rest energy after the TM target braking power  208  regenerated back to the energy source  102  is smaller than the maximum loss power of the TM  106 , also i.e., when the TM  106  may bear the rest energy after the TM target braking power  208  charging the energy source  102 , it may regenerate a portion of the TM target braking power  208  back to the energy source  102 , and the rest portion is dissipated in the TM  106 . In other embodiments, when the state of charge of the energy source  102  denotes the energy source  102  does not have enough capacity to receive all the TM target braking power  208 , and the rest energy after the TM target braking power  208  regenerated to the energy source  102  is larger than the maximum loss power of the TM  106 , also i.e., the TM  106  fails to bear rest energy after the TM target braking power  208  charging the energy source  102 , a portion of the TM target braking power  208  is dissipated in the mechanical braking device. 
     In an embodiment, the method  1100  still includes a step  1108  where the TM target loss power is generated according to step  1106  operating energy distribution rules. As above, the TM target loss power has different values in different conditions. 
     In an embodiment, the method  1100  still includes a step  1110  where the TM target loss power is generated at least according to the reference current signal. In an embodiment, the reference current calculation unit  228  as  FIG. 6  may be configured to calculate the reference current magnitude  232  in accordance with the TM target dump  226 . 
     In an embodiment, the method  1100  still includes a step  1112  where motor control is implemented based at least in part on a current command (e.g. reference current magnitude signal) produced in the step  1110  and a current phase delay command of another one control circuit. In an embodiment, the TM control unit  242  in  FIG. 6  is configured to generate the control signal  244  according to the current magnitude reference signal  232  and the current phase delay command  238 , to control the power  124  transferred from the TM convertor  104  to the TM  106 , thus the power from the TM  106  in braking is distributed reasonably. 
     Understandably, the method  1100  for controlling the vehicle in  FIG. 11  may be changed in a specific way. For example,  FIG. 12  is a flow chart of the method  1300  for controlling the vehicle according to another embodiment. The method  1200  in  FIG. 12  is substantially similar to the method  1100  in  FIG. 11 . For example,  FIG. 12  still includes the step  1102 ,  1104 ,  1106  and  1108 , etc. Specially, in the embodiment of  FIG. 12 , the method  1200  still includes a step  1109  after the step  1108  where the target loss power in  1108  is limited so as to avoid the target loss power exceeding the maximum loss value of the TM. In an embodiment shown in  FIG. 7 , the magnitude limit element  252  is configured to limit the target loss power value  226  according to the maximum motor loss value and minimum motor loss value relative to the TM  106 . Afterwards, in the step  1110 , the reference current command is generated based on the limited target loss power, such as a reference current magnitude command. 
       FIG. 13  is a flow chart of the method  1300  for controlling the vehicle according to another embodiment. Specially, the method  1300  is configured to distribute the energy generated by the PTO motor of the vehicle in braking. 
     In an embodiment, the method includes a step  1302  where the PTO target braking torque is received. In some embodiments, the controller  116  (shown in  FIG. 3 ) receives the second command  138  which instructs the desirably obtaining braking torque corresponding to the PTO motor  148 , and in different working conditions the second command  138  may have different values. For example, in some cases, for the security concern, when the PTO device  152  (e.g. a rotary cutter) drove by the PTO motor  148  works abnormally, the braking torque command with a relative large value is input to be braked fast. And when PTO device  152  works normally, the braking torque command with a small value is input. 
     In an embodiment, the method  1300  still includes a step  1304  where a PTO target braking power is generated based at least in part on the PTO target braking torque from the step  1302 . For instance, in an embodiment, when the controller  116  operates the PTO electric-brake control algorithm  123 , the PTO braking power calculation unit  304  in  FIG. 10  is employed to calculate the PTO target braking power according to the PTO motor target braking torque  302  and the PTO motor feedback velocity  306 . 
     In an embodiment, the method  1300  still includes a step  1306  where a PTO target loss power is generated. In an embodiment, the PTO target loss power calculation unit  312  in  FIG. 10  may be employed to subtract the PTO motor target braking power  308  from the energy source target charge energy (or energy source chargeable energy)  224  to obtain the PTO motor target loss power  314 . 
     In an embodiment, the method  1300  still includes a step  1308  where a reference current signal (or current command) is generated based at least in part on the PTO motor target loss power from the step  1306 . In an embodiment, the reference current calculation unit  312  in  FIG. 10  may be employed to calculate the reference current magnitude signal  318  according to the PTO motor target loss power  314 . 
     In an embodiment, the method  1300  still includes a step  1310  where the motor control is implemented based at least in part on the reference current signal (e.g. reference current magnitude signal) from the step  1308  and the current phase delay command of another one control circuit. In an embodiment, the PTO motor control unit  328  in  FIG. 10  is employed to generate the control signal  332  according to the current magnitude reference signal  312  and the current phase delay command  326 , to control the power  124  transferred from the PTO motor convertor  144  to the PTO motor  148 , thus the energy from the PTO motor  148  in braking is distributed reasonably. 
     Understandably, the method  1300  controlling the vehicle operating in  FIG. 13  may be changed in a specific way. For example,  FIG. 14  is a flow chart of a method  1400  for controlling the vehicle according to another embodiment. The method  1400  in  FIG. 14  is substantially similar to the method  1300  in  FIG. 13 . For example,  FIG. 14  still includes a step  1302 ,  1304 ,  1306 ,  1308  and  1310 . Specially, in the embodiment of  FIG. 14 , the method  1400  still includes the step  1305  after the step  1304  where the PTO motor target braking power from the step  1304  is distributed in a pre-set rule. In an embodiment, when operating the step  1305 , the power is distributed according to the state of charge of the energy source  102 . For example, when the energy source  102  could receive all PTO target braking power, all the PTO target braking power generated by the PTO motor according to the target braking torque is transferred to the energy source  102 . When the energy source  102  fails to receive all PTO target braking power, the rest energy after the PTO motor target braking power is supplied to the energy source  102  may be dissipated in the PTO motor  148 . In another embodiment, a portion of the rest power after the PTO motor target braking power supplied to the energy source  102  is dissipated in the PTO motor  148 , and the other portion dissipates in the dump or the braking resistor  342 . 
     Furthermore, in some embodiments, similar to operating the TM electric-brake control method, the method  1400  after the step  1306  may also include a step where the PTO target loss power is limited according to maximum motor loss value and the minimum motor loss value of the PTO motor. If the PTO target loss value is larger than the maximum motor loss value generated from the PTO motor, in an embodiment, a braking resistor may be used to dissipate extra energy. 
     While only certain features of the invention have been illustrated and described herein in conjunction with typical embodiments, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit and scope of the invention.