Patent ID: 12202361

DESCRIPTION OF EMBODIMENTS

To enable a person skilled in the art to better understand technical solutions provided in embodiments of this application, the following first describes a motor drive system.

Still refer to the motor drive system shown inFIG.1. A power battery pack101of an electric vehicle includes a plurality of batteries connected in series and in parallel. Generally, the batteries are first connected in parallel, and then connected in series. No switch is disposed inside the power battery pack. Therefore, a high-voltage direct current continuously exists at two ends of the power battery pack, and a voltage range is generally between 200 V and 800 V. A DC-AC circuit102can invert a direct current that is output by the power battery pack101into an alternating current, and provide the alternating current for a motor103.

When some batteries in the power battery pack are faulty, a protection system of the electric vehicle is triggered. The protection system controls the power battery pack to stop supplying power to the DC-AC circuit102, so that the electric vehicle stops. In actual application, the electric vehicle can only passively wait for rescue, but cannot actively travel to a maintenance station.

To resolve the foregoing technical problem, this application provides a motor drive system, a power system, and a drive method. A power battery pack corresponding to the drive system includes at least two battery modules that are independent of each other. The drive system includes at least two DC-AC circuits, and the battery modules one-to-one correspond to the DC-AC circuits. In other words, a quantity of the battery modules is the same as a quantity of the DC-AC circuits. Each battery module is correspondingly connected to an input end of one DC-AC circuit, and an output end of each DC-AC circuit is correspondingly connected to one winding of the motor, that is, the DC-AC circuits one-to-one correspond to each winding of the motor. When a battery module is faulty, normal power supply by another battery module is not affected, and the other battery module that normally supplies power may continue to supply power to a corresponding motor winding. In this way, a vehicle can continue to travel.

To make a person skilled in the art better understand the technical solutions in this application, the following clearly describes the technical solutions in embodiments of this application with reference to the accompanying drawings in embodiments of this application.

It may be understood that terms such as “first” and “second” in embodiments of this application are merely used for ease of description, and do not constitute a limitation on this application.

Drive System Embodiment 1

An embodiment of this application provides a motor drive system, used in an electric vehicle, and configured to drive a motor of the electric vehicle. The electric vehicle includes a power battery pack. The power battery pack may include a plurality of batteries. The plurality of batteries form at least two battery modules that are independent of each other. A quantity of battery modules may be determined based on an actual situation. This is not limited in this embodiment of this application. The following provides descriptions with reference to the accompanying drawings.

Refer toFIG.2.FIG.2is a schematic diagram of a motor drive system according to an embodiment of this application.

The drive system includes DC-AC circuits102a1to102an.

Battery modules are101a1,101a2, . . . , and101an, and the battery modules are independent of each other. n indicates a quantity of the battery modules. For example, when n=2, the power battery pack includes a battery module101a1and a battery module101a2.

Output voltages of the battery modules may be equal or not equal. In other words, quantities of batteries included in the battery modules may be equal or not equal. This is not limited in this embodiment of this application.

For example, an output voltage of the battery module101a1may be 36 V, and an output voltage of the battery module101a2may be 24 V.

In actual application, an insulation system between a live metal part of the battery module and a metal part of a vehicle frame may be damaged, or insulation performance may deteriorate (which may be caused by abnormalities such as external force extrusion, collision, or puncture of the battery module in actual application). This may cause uncontrollable discharge of battery energy, electric leakage, or the like. To reduce safety risks, the output voltage of the battery module101a1may be set to be not higher than a safe voltage across a human body.

A quantity of the DC-AC circuits is the same as a quantity of the battery modules, and each battery module is correspondingly connected to an input end of one DC-AC circuit. In some embodiments, the battery module101a1is connected to the DC-AC circuit102a1, the battery module101a2is connected to the DC-AC circuit102a2, . . . , and the battery module101anis connected to the DC-AC circuit102an.

An output end of each DC-AC circuit is correspondingly connected to a winding of a motor103, and a quantity of the motor windings is the same as a quantity of the DC-AC circuits.

InFIG.2, the motor winding being a three-phase winding is used as an example. In this case, a correspondingly connected DC-AC circuit may be a two-level three-phase half-bridge DC-AC circuit, a two-level three-phase full-bridge DC-AC circuit, or a multi-level DC-AC circuit.

The DC-AC circuit is configured to convert a direct current provided by the corresponding battery module into an alternating current to drive a winding of the motor103.

The battery modules correspondingly connected to the DC-AC circuits are independent of each other. When some battery modules are faulty, normal power supply by another battery module is not affected. In actual application, the DC-AC circuit that is correspondingly connected to the faulty battery module may further stop working, implementing fault source isolation. This prevents escalation of fault impact and reduces an accident risk.

For example, when the battery module101a1is faulty, the DC-AC circuit102a1correspondingly connected to the battery module101a1stops working, so that the faulty battery module101a1stops supplying power to the corresponding motor winding.

In this case, another battery module that works normally can continue to supply power to a corresponding motor winding. In this way, the vehicle can continue to travel.

Refer toFIG.3.FIG.3is a schematic diagram of arrangement of motor windings according to an embodiment of this application.

The arrangement manner of the motor windings shown in the figure corresponds toFIG.2. A quantity of the windings of the motor is n times of 3, where n is an integer greater than or equal to 2. That is, the motor includes n three-phase windings: U1/V1/W1, U2/V2/W2, . . . , and Un/Vn/Wn. For each three-phase winding, three phases of each three-phase winding are interlaced with each other at phase angles of 120°.

In addition, every two adjacent three-phase windings are interlaced at a first preset angle, and a value range of the first preset angle is 0° to 180°. For example, when n=3 and the first preset angle is 60°, a phase angle of the winding U2/V2/W2may lead a phase angle of the winding U1N1/W1by 60°, and a phase angle of the winding U3/V3/W3may lead the phase angle of the winding U2/V2/W2by 60°. A value of the first preset angle may be determined based on an actual situation. This is not limited in this embodiment of this application.

Refer toFIG.4.FIG.4is a schematic diagram of another motor drive system according to an embodiment of this application.

The drive system shown inFIG.4differs from the drive system shown inFIG.2in that a winding used by a motor103is a two-phase winding. In this case, a correspondingly connected DC-AC circuit may be a DC-AC circuit of a full-bridge structure.

For descriptions of battery modules and a working principle, refer to a corresponding part in the description inFIG.2. Details are not described herein again.

Refer toFIG.5.FIG.5is a schematic diagram of another arrangement of motor windings according to an embodiment of this application.

The arrangement manner of the motor windings shown in the figure corresponds toFIG.4. In this case, a quantity of the windings of the motor is n times of 2, where n is an integer greater than or equal to 2. That is, the motor includes n two-phase windings: U1/V1, U2/V2, and Un/Vn. Both ends of each phase of each winding of the motor are led out and connected to a DC-AC circuit.

In conclusion, the power battery pack corresponding to the drive system provided in this embodiment of this application includes at least two battery modules that are independent of each other. The drive system includes at least two DC-AC circuits, and the battery modules one-to-one correspond to the DC-AC circuits. In other words, a quantity of the battery modules is the same as a quantity of the DC-AC circuits. Each battery module is correspondingly connected to an input end of one DC-AC circuit, and an output end of each DC-AC circuit is correspondingly connected to one winding of the motor, that is, the DC-AC circuits one-to-one correspond to each winding of the motor. The DC-AC circuit can convert a direct current provided by the corresponding battery module into an alternating current to drive a winding of the motor. In the solutions of this application, the power battery pack is divided into battery modules that are independent of each other, and each battery module supplies power to a winding of the motor by using a DC-AC circuit corresponding to the battery module. Therefore, when a battery module is faulty, normal power supply by another battery module is not affected, and the other battery module that supplies power normally can continue to supply power to a corresponding motor winding. In this way, the electric vehicle can continue to travel.

The drive system further includes a component having a control function, and can control a working status of each DC-AC circuit. The following describes an embodiment and a working principle of the component having a control function with reference to the accompanying drawings. In the following embodiment, an example in which the winding of the motor is a three-phase winding is used. It may be understood that a principle is similar when the winding of the motor is a two-phase winding.

Drive System Embodiment 2

Refer toFIG.6.FIG.6is a schematic diagram of still another motor drive system according to an embodiment of this application.

A motor of the drive system uses a three-phase winding, and further includes a vehicle control unit104, a primary controller105, and secondary controllers106a1to106an.

Each DC-AC circuit corresponds to one secondary controller. In other words, a quantity of the secondary controllers is the same as a quantity of the DC-AC circuits. The secondary controller can control a working status of a correspondingly connected DC-AC circuit. In actual application, the secondary controller may control the working status of the DC-AC circuit by sending a drive signal to each controllable switching transistor in the correspondingly connected DC-AC circuit. The drive signal may be a PWM (pulse-width modulation) signal.

Working data of batteries in a power battery pack may be collected by using a temperature sensor, a voltage sensor, a current sensor, and the like. Whether a battery is faulty may be determined based on the sampled working data.

In some embodiments, the vehicle control unit104may determine a faulty battery module based on the sampled working data. In some embodiments, another component having a data processing function on an electric vehicle may determine a faulty battery module based on the sampled working data, and notify the vehicle control unit104of a corresponding result. This is not limited in this embodiment of this application.

When determining that some battery modules are faulty, the vehicle control unit104sends a disable instruction to a secondary controller corresponding to the faulty battery module by using the primary controller105, so that the secondary controller receiving the disable instruction controls a corresponding DC-AC circuit to stop working, implementing fault isolation.

In addition, the vehicle control unit104may further report a fault status to a driver, for example, by displaying the fault status on a display of the vehicle or giving a voice notification.

A DC-AC circuit corresponding to another battery module that works normally may continue to work or be disabled based on a control logic of the vehicle control unit104or an instruction delivered by the vehicle driver.

In actual application, the vehicle control unit104may further determine fault severity and correspondingly execute different control logics.

For example, when determining that a battery module has a critical fault, for example, a risk of fire or explosion, the vehicle control unit104may send a disable instruction to all secondary controllers by using the primary controller105, so that all DC-AC circuits stop working, and the driver may further be prompted to leave the vehicle.

For another example, when determining that a battery module has a minor fault, for example, low battery or poor contact of the battery, the vehicle control unit104sends a disable instruction to a secondary controller corresponding to the faulty battery module by using the primary controller105, so that the secondary controller controls a corresponding DC-AC circuit to stop working, and another battery module that works normally may continue to supply power to a corresponding motor winding. In this way, the vehicle can continue to travel.

The following provides descriptions with reference to the accompanying drawings.

Refer toFIG.7.FIG.7is a diagram of a control sequence of DC-AC circuits according to an embodiment of this application.

In an example in which the vehicle control unit104determines that a battery module101axis faulty (x may be any value from 1 to n) and the fault is a minor fault, the vehicle control unit104sends a disable instruction to a secondary controller corresponding to the faulty battery module101axby using the primary controller, so that the secondary controller controls the corresponding DC-AC circuit102axto stop working, and other DC-AC circuits such as102a1and102a2may continue to work normally. In this way, the electric vehicle can continue to travel.

The vehicle control unit104may further determine a quantity of working DC-AC circuits based on a load of the motor. The following provides descriptions with reference to the accompanying drawings.

Refer toFIG.8.FIG.8is a sequence diagram of a correspondence between a load of a motor and a working status of each DC-AC circuit according to an embodiment of this application.

The vehicle control unit104may obtain a load of the motor, and send a control instruction to the primary controller105based on the load.

The primary controller105controls a quantity of working DC-AC circuits based on the control instruction, and the quantity of working DC-AC circuits is positively correlated with the load. In other words, as the load increases, more DC-AC circuits are gradually put into operation.

In conclusion, according to the control system provided in this embodiment of this application, when determining that a battery module is faulty, the vehicle control unit can send a disable instruction to a secondary controller corresponding to the faulty battery module by using the primary controller, so that the secondary controller receiving the disable instruction controls a corresponding DC-AC circuit to stop working, to reduce impact caused by the fault and implement fault isolation. In addition, another battery module that supplies power normally can continue to supply power to a corresponding motor winding. In this way, the electric vehicle can continue to travel.

Further, according to the motor drive system provided in this embodiment of this application, the vehicle control unit can further send a control instruction to the primary controller based on a load of the motor, so that the primary controller controls a quantity of working DC-AC circuits based on the control instruction. In other words, a quantity of battery modules that supply power can be selected based on a scenario of the electric vehicle. This reduces energy consumption and prolongs an endurance mileage of a power battery pack.

In addition, when a motor winding is faulty, the control system provided in this embodiment of this application can further perform fault isolation. Details are described below. The fault of the motor winding includes at least one of a winding short-circuit fault and a winding open-circuit fault.

In some embodiments, when it is determined that a motor winding is faulty, the primary controller can control a DC-AC circuit corresponding to the faulty winding to stop working, implementing fault isolation.

In some embodiments, the vehicle control unit may determine a faulty motor winding, and send a disable instruction to a secondary controller corresponding to the faulty winding by using the primary controller, so that the secondary controller receiving the disable instruction controls a corresponding DC-AC circuit to stop working, implementing fault isolation.

In the foregoing embodiment, that the vehicle control unit delivers a control instruction controlling a DC-AC circuit to a secondary controller by using the primary controller is used as an example. The following describes another manner of controlling the DC-AC circuit with reference to the accompanying drawings.

Drive System Embodiment 3

Still refer to the motor drive system shown inFIG.6. The drive system provided in this embodiment of this application also includes a vehicle control unit104, a primary controller105, and secondary controllers106a1to106an. A difference lies in that, when it is determined that a battery module is faulty, the primary controller105in this embodiment of this application is configured to: send a disable instruction to a secondary controller corresponding to the faulty battery module, so that the secondary controller receiving the disable instruction controls a corresponding DC-AC circuit to stop working; and send fault information of the faulty battery module to the vehicle control unit104. The vehicle control unit104is configured to notify a driver of the fault information, for example, by displaying the fault information on a display of a vehicle or giving a voice notification. Details are described below.

Working data of batteries in a power battery pack may be collected by using a temperature sensor, a voltage sensor, a current sensor, and the like. Whether a battery is faulty may be determined based on the sampled working data.

In some embodiments, the primary controller105may determine a faulty battery module based on the sampled working data. In some embodiments, another component having a data processing function on an electric vehicle may determine a faulty battery module based on the sampled working data, and notify the primary controller105of a corresponding result. This is not limited in this embodiment of this application.

When determining that a battery module is faulty, the primary controller105sends a disable instruction to a secondary controller corresponding to the faulty battery module, so that the secondary controller receiving the disable instruction controls a corresponding DC-AC circuit to stop working, implementing fault isolation. The primary controller105may further feedback the fault information to the vehicle control unit105.

A DC-AC circuit corresponding to another battery module that works normally may continue to work or be disabled based on a control logic of the primary controller105or an instruction delivered by the vehicle driver.

For example, when determining that a battery module has a critical fault, for example, a potential risk of fire or explosion, the primary controller105may send a disable instruction to all secondary controllers, so that the secondary controllers control all DC-AC circuits to stop working. In addition, fault information may further be sent to the vehicle control unit105, to prompt the driver to leave the vehicle.

For another example, when determining that a battery module has a minor fault, for example, low battery or poor contact of the battery, the primary controller105sends a disable instruction only to a secondary controller corresponding to the faulty battery module, to control only a DC-AC circuit corresponding to the faulty battery module to stop working, and a DC-AC circuit corresponding to another battery module that works normally may normally work. In this way, the vehicle can continue to travel.

Still refer to the diagram of the control sequence shown inFIG.7. In an example in which the primary controller105determines that a battery module101ax(x may be any value from 1 to n) is faulty and the fault is a minor fault, the primary controller sends a disable instruction to a secondary controller106ax, so that the secondary controller106axcontrols, based on the disable instruction, a DC-AC circuit102axto stop working, and another DC-AC circuit can continue to work normally. In this way, the electric vehicle can continue to travel.

Still refer to the sequence diagram shown inFIG.8. The vehicle control unit104may further determine a working status of each DC-AC circuit based on a load of the motor.

The vehicle control unit104may obtain a load of the motor, and send a control instruction to the primary controller105based on the load. In this case, the control instruction may further include an ID of each DC-AC circuit that needs to be put into operation.

The primary controller105may control, by using the secondary controller, a quantity of working DC-AC circuits based on the control instruction, and the quantity of working DC-AC circuits is positively correlated with the load. In other words, as the load increases, more DC-AC circuits are gradually put into operation.

In conclusion, according to the control system provided in this embodiment of this application, when determining that a battery module is faulty, the primary controller sends a disable signal to a secondary controller corresponding to the faulty battery module, so that the secondary controller controls a corresponding DC-AC circuit to stop working, to reduce impact caused by the fault and implement fault isolation. A DC-AC circuit corresponding to another battery module that works normally may normally work. In this way, the vehicle can continue to travel, facilitating vehicle rescue. Therefore, redundancy of the drive system is further improved.

Further, according to the motor drive system provided in this embodiment of this application, the vehicle control unit can further send a control instruction to the primary controller based on a load of the motor, so that the primary controller controls, by using the secondary controller, a quantity of working DC-AC circuits based on the control instruction. In other words, a quantity of battery modules that supply power can be selected based on a scenario of the electric vehicle. This reduces energy consumption and prolongs an endurance mileage of a power battery pack.

In addition, when a motor winding is faulty, the control system provided in this embodiment of this application can further perform fault isolation. Details are described below.

In some embodiments, when determining that a motor winding is faulty, the primary controller in this embodiment of this application can further send a disable instruction to a secondary controller corresponding to the faulty winding, so that the secondary controller controls a corresponding DC-AC circuit to stop working, implementing fault isolation.

In some embodiments, the vehicle control unit may determine a faulty motor winding, and send a disable instruction to a secondary controller corresponding to the faulty winding by using the primary controller, so that the secondary controller controls a corresponding DC-AC circuit to stop working, implementing fault isolation.

The foregoing embodiment is described by using an example in which a drive system includes a vehicle control unit, a primary controller, and a secondary controller. The following describes another manner of controlling a DC-AC circuit with reference to the accompanying drawings.

Drive System Embodiment 4

Refer toFIG.9.FIG.9is a schematic diagram of yet another motor drive system according to an embodiment of this application.

The drive system corresponds toFIG.2. A motor uses a three-phase winding, and the drive system further includes a vehicle control unit104and a primary controller105.

The primary controller105is separately connected to each DC-AC circuit, and can control a working status of each DC-AC circuit.

Working data of batteries in a power battery pack may be collected by using a temperature sensor, a voltage sensor, a current sensor, and the like. Whether a battery is faulty may be determined based on the sampled working data.

In some embodiments, the vehicle control unit104may determine a faulty battery module based on the sampled working data. In some embodiments, another component having a data processing function on an electric vehicle may determine a faulty battery module based on the sampled working data, and notify the vehicle control unit104of a corresponding result. This is not limited in this embodiment of this application.

The battery module is numbered in advance, ID of the battery module is obtained, and a correspondence between the battery module and the ID is stored in the vehicle control unit104.

When determining that a battery module is faulty, the vehicle control unit104can send a disable instruction to the primary controller105. The disable instruction carries an ID of the faulty battery module, and can indicate a DC-AC circuit that needs to be disabled.

When receiving the disable instruction, the primary controller105controls, based on the ID of the faulty battery module, a DC-AC circuit corresponding to the faulty battery module to stop working, implementing fault isolation. In addition, the vehicle control unit104may further notify a driver of a fault status, for example, by displaying the fault status on a display of the vehicle or giving a voice notification.

A DC-AC circuit corresponding to another battery module that works normally may continue to work or be disabled based on a control logic of the vehicle control unit104or an instruction delivered by the vehicle driver.

In actual application, the vehicle control unit104may further determine fault severity and correspondingly execute different control logics.

For example, when determining that a battery module has a critical fault, for example, a risk of fire or explosion, the vehicle control unit104may send, to the primary controller105, a disable instruction carrying IDs of all battery modules, so that the primary controller105controls all DC-AC circuits to stop working, and the driver may further be prompted to leave the vehicle.

For another example, when determining that a battery module has a minor fault, for example, low battery or poor contact of the battery, the vehicle control unit104may control only a DC-AC circuit corresponding to the faulty battery module to stop working, and another battery module that works normally may continue to supply power to a corresponding motor winding. In this way, the vehicle can continue to travel to a maintenance point.

The following provides descriptions with reference to the accompanying drawing.

Still refer to the diagram of the control sequence shown inFIG.7. In an example in which the vehicle control unit104determines that a battery module101ax(x may be any value from 1 to n) is faulty and the fault is a minor fault, the vehicle control unit sends, to the primary controller, a disable instruction carrying an ID of the battery module101ax, so that the primary controller controls a DC-AC circuit102axto stop working, and other DC-AC circuits such as102a1and102a2may continue to work normally. In this way, the electric vehicle can continue to travel.

Still refer to the sequence diagram shown inFIG.8. The vehicle control unit may further determine a working status of each DC-AC circuit based on a load of the motor.

The vehicle control unit104may obtain a load of the motor, and send a control instruction to the primary controller105based on the load. In this case, the control instruction further includes an ID of each DC-AC circuit that needs to be put into operation.

The primary controller105controls a quantity of working DC-AC circuits based on the control instruction, and the quantity of working DC-AC circuits is positively correlated with the load. In other words, as the load increases, more DC-AC circuits are gradually put into operation.

In conclusion, according to the control system provided in this embodiment of this application, when determining that a battery module is faulty, the vehicle control unit can send, to the primary controller, a disable instruction carrying an ID of the faulty battery module, so that the primary controller controls, based on the disable instruction, a corresponding DC-AC circuit to stop working, to reduce impact caused by the fault and implement fault isolation. A DC-AC circuit corresponding to another battery module that works normally may normally work. In this way, the vehicle can continue to travel, facilitating vehicle rescue. Therefore, redundancy of the drive system is further improved. In addition, a circuit structure is simplified and costs are reduced because no secondary controller is needed.

Further, according to the motor drive system provided in this embodiment of this application, the vehicle control unit can further send a control instruction to the primary controller based on a load of the motor, so that the primary controller controls a quantity of working DC-AC circuits based on the control instruction. In other words, a quantity of battery modules that supply power can be selected based on a scenario of the electric vehicle. This reduces energy consumption and prolongs an endurance mileage of a power battery pack.

In addition, when a motor winding is faulty, the control system provided in this embodiment of this application can further perform fault isolation. Details are described below.

In some embodiments, when it is determined that a motor winding is faulty, the primary controller can control a DC-AC circuit corresponding to the faulty winding to stop working, implementing fault isolation.

In some embodiments, the vehicle control unit may determine a faulty motor winding, and send a disable instruction to the primary controller, so that the primary controller controls a corresponding DC-AC circuit to stop working, implementing fault isolation.

The foregoing embodiment is described by using an example in which a vehicle control unit sends, to a primary controller, a disable instruction carrying an ID of a faulty battery module, and then the primary controller controls a working status of a DC-AC circuit based on the disable instruction. The following describes still another manner of controlling a DC-AC circuit with reference to the accompanying drawings.

Drive System Embodiment 5

Still refer to the schematic diagram of the motor drive system shown inFIG.9.

As described in Embodiment 4, the motor drive system provided in this embodiment of this application also includes a vehicle control unit104and a primary controller105.

However, a difference lies in that, when it is determined that a battery module is faulty, the primary controller105in this embodiment of this application is configured to control a DC-AC circuit corresponding to the faulty battery module to stop working, and send fault information of the faulty battery module to the vehicle control unit104. The vehicle control unit105is configured to notify a driver of the fault information, for example, by displaying the fault information on a display of a vehicle or giving a voice notification. Details are described below.

Working data of batteries in a power battery pack may be collected by using a temperature sensor, a voltage sensor, a current sensor, and the like. Whether a battery is faulty may be determined based on the sampled working data.

In some embodiments, the primary controller105may determine a faulty battery module based on the sampled working data. In some embodiments, another component having a data processing function on an electric vehicle may determine a faulty battery module based on the sampled working data, and notify the primary controller105of a corresponding result. This is not limited in this embodiment of this application.

When determining that a battery module is faulty, the primary controller105controls a DC-AC circuit corresponding to the faulty battery module to stop working, implementing fault isolation. In addition, fault information is fed back to the vehicle control unit105.

A DC-AC circuit corresponding to another battery module that works normally may continue to work or be disabled based on a control logic of the primary controller105or an instruction delivered by the vehicle driver.

In actual application, the primary controller105may further determine fault severity and correspondingly execute different control logics.

For example, when determining that a battery module has a critical fault, for example, a potential risk of fire or explosion, the primary controller105may control all DC-AC circuits to stop working, and may further send fault information to the vehicle control unit105, to prompt the driver to leave the vehicle.

For another example, when determining that a battery module has a minor fault, for example, low battery or poor contact of the battery, the primary controller105may control only a DC-AC circuit corresponding to the faulty battery module to stop working, and another battery module that works normally may continue to supply power to a corresponding motor winding. In this way, the vehicle can continue to travel.

The following provides descriptions with reference to the accompanying drawing.

Still refer to the diagram of the control sequence shown inFIG.7. In an example in which the primary controller105determines that a battery module101ax(x may be any value from 1 to n) is faulty and the fault is a minor fault, the primary controller controls a DC-AC circuit102axto stop working, and other DC-AC circuits such as102a1and102a2may continue to work normally. Another battery module that works normally may continue to supply power to a corresponding motor winding. In this way, the vehicle can continue to travel.

Still refer to the sequence diagram shown inFIG.8. The vehicle control unit104may further determine a working status of each DC-AC circuit based on a load of the motor.

The vehicle control unit104may obtain a load of the motor, and send a control instruction to the primary controller105based on the load. In this case, the control instruction may further include an ID of each DC-AC circuit that needs to be put into operation.

The primary controller105controls a quantity of working DC-AC circuits based on the control instruction, and the quantity of working DC-AC circuits is positively correlated with the load. In other words, as the load increases, more DC-AC circuits are gradually put into operation.

In conclusion, according to the control system provided in this embodiment of this application, when determining that a battery module is faulty, the primary controller can control a corresponding DC-AC circuit to stop working, to reduce impact caused by the fault and implement fault isolation. In addition, a DC-AC circuit corresponding to a battery module that works normally can be controlled to continue working, so that another battery module that works normally can continue to supply power to a corresponding motor winding, facilitating vehicle rescue. Therefore, redundancy of the drive system is further improved. In addition, a circuit structure is simplified and costs are reduced because no secondary controller is needed.

Further, according to the motor drive system provided in this embodiment of this application, the vehicle control unit can further send a control instruction to the primary controller based on a load of the motor, so that the primary controller controls a quantity of working DC-AC circuits based on the control instruction. In other words, a quantity of battery modules that supply power can be selected based on a scenario of the electric vehicle. This reduces energy consumption and prolongs an endurance mileage of a power battery pack.

In addition, when a motor winding is faulty, the control system provided in this embodiment of this application can further perform fault isolation. Details are described below.

In some embodiments, when it is determined that a motor winding is faulty, the primary controller in this embodiment of this application can control a DC-AC circuit corresponding to the faulty winding to stop working, implementing fault isolation.

In some embodiments, the vehicle control unit may determine a faulty motor winding, and notify the primary controller, so that the primary controller controls a corresponding DC-AC circuit to stop working, implementing fault isolation.

The foregoing drive systems provided in drive system embodiment 2 to embodiment 5 are described by using an example in which the motor winding is a three-phase winding. It may be understood that when the motor winding is a two-phase winding, the control manners provided in Embodiment 2 to Embodiment 5 are also applicable. Details are not described again in embodiments of this application.

In addition, a negative electrode of each battery module may or may not be connected to a common reference ground. This is not limited in embodiments of this application.

Further, an example in which the DC-AC circuit is a two-level three-phase half-bridge circuit is used in the foregoing embodiments. In actual application, the DC-AC circuit may also be a two-level three-phase full-bridge circuit, a multi-level circuit, or another circuit that can implement direct current-alternating current conversion. The following uses an example in which the DC-AC circuit is a two-level three-phase full-bridge circuit for description.

Refer toFIG.10.FIG.10is a schematic diagram of a two-level three-phase full-bridge circuit according to an embodiment of this application.

U1and U2are outputs of a first group of full-bridge inverters, V1and V2are outputs of a second group of full-bridge inverters, and W1and W2are outputs of a third group of full-bridge inverters.

The following uses an example in which a motor uses a three-phase winding, a DC-AC circuit uses a two-level three-phase half-bridge circuit, and a negative electrode of each battery module is connected to a common reference ground to describe a working principle of charging the battery module by using the drive system provided in this application.

Drive System Embodiment 6

Refer toFIG.11.FIG.11is a schematic diagram of charging of a drive system according to an embodiment of this application.

For descriptions of the drive system, refer to the foregoing embodiments. Details are not described herein again in this embodiment of this application. It should be noted that negative electrodes of battery modules in the drive system provided in this embodiment of this application are connected to a common reference ground.

When a power battery pack is being charged, an external charger200may be connected. One end of the charger200is connected to a common tap of windings of a three-phase motor, and the other end is connected to the common reference ground of the battery modules of the drive system.

The charger200may output a direct-current voltage, or may output an alternating-current voltage. The following provides separate descriptions.

When the charger200outputs a direct current, a current flow direction in a charging process is shown by arrow directions inFIG.11. The charging current sequentially flows through the motor winding, a DC-AC circuit, and the battery module, and flows back to the charger through the common reference ground.

When the charger200outputs an alternating current, a controllable switching transistor in a DC-AC circuit may be controlled to convert a current flowing through the DC-AC circuit into a direct current, and then the direct current is transmitted to a corresponding battery module. In this case, the DC-AC circuit is configured to implement alternating current-direct current conversion, and is equivalent to an inverter.

For the foregoing two cases, a working status of the switching transistor of the DC-AC circuit needs to be controlled. The following describes various embodiments.Embodiment 1: The drive system includes a vehicle control unit, a primary controller, and a secondary controller.

When determining that the drive system is charging the battery modules, the vehicle control unit determines, based on a type of an output current (a direct current or an alternating current) of a charging pile and working statuses of the battery modules and the windings (whether a fault occurs), a control instruction corresponding to each DC-AC circuit.

The vehicle control unit sends the control instruction to each corresponding secondary controller by using the primary controller, so that each secondary controller controls a working status of a controllable switching transistor in a corresponding DC-AC circuit based on the control instruction, to charge batteries in the battery modules.Embodiment 2: The drive system includes a vehicle control unit, a primary controller, and a secondary controller.

When determining that the drive system is charging the battery modules, the primary controller determines, based on a type of an output current (a direct current or an alternating current) of a charging pile and working statuses of the battery modules and the windings (whether a fault occurs), a control instruction corresponding to each DC-AC circuit.

The primary controller sends the control instruction to each corresponding secondary controller, so that each secondary controller controls a working status of a controllable switching transistor in a corresponding DC-AC circuit based on the control instruction, to charge batteries in the battery modules.

The primary controller can further feedback charging information to the vehicle control unit, so that the vehicle control unit displays the charging information on a display. The charging information is not limited in this embodiment of this application. For example, the charging information may include an ID of a battery module that is being charged.Embodiment 3: The drive system includes a vehicle control unit and a primary controller.

When determining that the drive system is charging the battery modules, the vehicle control unit determines, based on a type of an output current (a direct current or an alternating current) of a charging pile and working statuses of the battery modules and the windings (whether a fault occurs), a control instruction corresponding to each DC-AC circuit.

The vehicle control unit sends the control instruction to the primary controller, so that the primary controller controls a working status of a controllable switching transistor in a corresponding DC-AC circuit based on the control instruction, to charge batteries in the battery modules.Embodiment 4: The drive system includes a vehicle control unit and a primary controller.

When determining that the drive system is charging the battery modules, the primary controller controls, based on a type of an output current (a direct current or an alternating current) of a charging pile and working statuses of the battery modules and the windings (whether a fault occurs), a working status of a controllable switching transistor in each DC-AC circuit, to charge batteries in the battery modules.

The primary controller can further feedback charging information to the vehicle control unit, so that the vehicle control unit displays the charging information on a display.

In conclusion, when the battery modules are being charged by using the drive system provided in this application, the battery modules are independent of each other, and the charger can separately charge the battery modules. For a faulty battery module, charging of the faulty battery module may be stopped, and another normal battery module can still be normally charged without being affected. Therefore, redundancy of the drive system is improved.

Power System Embodiment

Based on the motor drive systems provided in the foregoing embodiments, an embodiment of this application further provides a power system. The power system may be used in an electric vehicle. The following provides descriptions with reference to the accompanying drawing.

Refer toFIG.12.FIG.12is a schematic diagram of a power system according to an embodiment of this application.

A power system300includes a power battery pack101, a drive system100, and a motor103.

The drive system100is configured to drive windings of the motor103.

The power battery pack101includes at least two battery modules that are independent of each other. The battery modules one-to-one correspond to DC-AC circuits. That is, as shown in the figure, each battery module corresponds to one DC-AC circuit, and each DC-AC circuit corresponds to one winding of the motor. A quantity of the battery modules is the same as a quantity of the DC-AC circuits.

Output voltages of the battery modules may be equal or not equal. In other words, quantities of batteries included in the battery modules may be equal or not equal. This is not limited in this embodiment of this application.

The drive system100includes DC-AC circuits102a1to102an.

The DC-AC circuit is configured to convert a direct current provided by the corresponding battery module into an alternating current to drive a winding of the motor.

For descriptions of the drive system100, refer to the foregoing drive system embodiments. Details are not described herein again in this embodiment of this application.

The motor103is configured to supply power to a load. The motor includes N windings, and a quantity of phases of each of the N windings may be 2 or 3. That is, the motor may include N two-phase windings or N three-phase windings. This is not limited in this embodiment of this application. N is an integer greater than or equal to 2.

Each winding of the motor103is correspondingly connected to an output end of one DC-AC circuit.

When the quantity of phases of each winding of the motor103is 2, that is, when the windings of the motor103are two-phase windings, the DC-AC circuit may be a full-bridge circuit, and two ends of each phase in each winding are respectively connected to two output ends of each phase in a corresponding DC-AC circuit.

When the quantity of phases of each winding of the motor103is 3, that is, when the windings are three-phase windings, the DC-AC circuit may be a two-level three-phase half-bridge circuit, a two-level three-phase full-bridge circuit, or a multi-level circuit. A first end of each phase in each winding is correspondingly connected to an output end of each phase in one DC-AC circuit, and a second end of each phase in each winding is connected together.

In some embodiments, when a quantity of the windings of the motor103is N times of 3, the windings of the motor may be six-phase windings, nine-phase windings, twelve-phase windings, fifteen-phase windings, or the like. This is not limited in this embodiment of this application.

A negative electrode of each battery module may or may not be connected to a common reference ground. This is not limited in embodiments of this application.

In conclusion, the power battery pack corresponding to the drive system of the power system includes at least two battery modules that are independent of each other. The drive system includes at least two DC-AC circuits, and the battery modules one-to-one correspond to the DC-AC circuits. In other words, a quantity of the battery modules is the same as a quantity of the DC-AC circuits. Each battery module is correspondingly connected to an input end of one DC-AC circuit, and an output end of each DC-AC circuit is correspondingly connected to one winding of the motor, that is, the DC-AC circuits one-to-one correspond to each winding of the motor. A quantity of phases of each winding of the motor may be 2 or 3. The DC-AC circuit can convert a direct current provided by the corresponding battery module into an alternating current to drive a winding of the motor. In the solutions of this application, the power battery pack is divided into battery modules that are independent of each other, and each battery module supplies power to a winding of the motor by using a DC-AC circuit corresponding to the battery module. Therefore, when a battery module is faulty, normal power supply by another battery module is not affected, and the other battery module that supplies power normally can continue to supply power to a corresponding motor winding.

The drive system can further control a quantity of working DC-AC circuits based on a load of the motor. That is, a quantity of battery modules that supply power can be selected based on a scenario in which an electric vehicle is located. This reduces energy consumption and prolongs an endurance mileage of the power battery pack.

It may be understood that the power system provided in this embodiment of this application may be further used in another scenario in which a motor winding is driven by using a battery pack. This is not limited in this embodiment of this application.

Method Embodiment

Based on the motor drive system provided in the foregoing embodiments, an embodiment of this application further provides a motor drive method. The following provides descriptions.

Refer toFIG.13.FIG.13is a flowchart of a motor drive method according to an embodiment of this application.

The method is used to drive a motor that uses a power battery pack as a power supply. The power battery pack includes at least two battery modules. The battery modules one-to-one correspond to DC-AC circuits. Each battery module corresponds to one DC-AC circuit, and each DC-AC circuit corresponds to one winding of the motor. A quantity of the battery modules is the same as a quantity of the DC-AC circuits. The windings of the motor may be two-phase windings or three-phase windings.

For descriptions of a motor drive system, refer to the foregoing embodiments. Details are not described herein again in this embodiment of this application.

The method is used to control a DC-AC circuit to convert a direct current provided by a corresponding battery module into an alternating current to drive a winding of the motor, and includes the following operations.S401: Control a DC-AC circuit corresponding to a faulty battery module to stop working when it is determined that the battery module is faulty.S402: Control a DC-AC circuit corresponding to a battery module that is not faulty to work normally when it is determined that the battery module is not faulty.

Because a device having a control function in the drive system may have different embodiments, the foregoing drive method also has different embodiments correspondingly. The following separately provides descriptions.Embodiment 1: The drive system includes a vehicle control unit, a primary controller, and a secondary controller.

When determining a battery module is faulty, the vehicle control unit sends a disable instruction to a secondary controller corresponding to the faulty battery module by using the primary controller, so that the secondary controller receiving the disable instruction controls a corresponding DC-AC circuit to stop working. The DC-AC circuit stops driving a winding of the motor, implementing fault isolation. In addition, the vehicle control unit may further report a fault status to a driver, for example, by displaying the fault status on a display of the vehicle or giving a voice notification.

A DC-AC circuit corresponding to another battery module that works normally may continue to work or be disabled based on a control logic of the vehicle control unit or an instruction delivered by the vehicle driver.Embodiment 2: The drive system includes a vehicle control unit, a primary controller, and a secondary controller.

When determining that a battery module is faulty, the primary controller sends a disable instruction to a secondary controller corresponding to the faulty battery module, so that the secondary controller receiving the disable instruction controls a corresponding DC-AC circuit to stop working, implementing fault isolation. In addition, fault information is fed back to the vehicle control unit.

A DC-AC circuit corresponding to another battery module that works normally may continue to work or be disabled based on a control logic of the primary controller or an instruction delivered by the vehicle driver.Embodiment 3: The drive system includes a vehicle control unit and a primary controller.

When receiving a disable instruction, the primary controller controls, based on an ID of a faulty battery module, a DC-AC circuit corresponding to the faulty battery module to stop working, implementing fault isolation. In addition, the vehicle control unit may further notify the driver of a fault status.

A DC-AC circuit corresponding to another battery module that works normally may continue to work or be disabled based on a control logic of the vehicle control unit or an instruction delivered by the vehicle driver.Embodiment 4: The drive system includes a vehicle control unit and a primary controller.

When determining that a battery module is faulty, the primary controller controls a DC-AC circuit corresponding to the faulty battery module to stop working, implementing fault isolation. In addition, fault information is fed back to the vehicle control unit.

A DC-AC circuit corresponding to another battery module that works normally may continue to work or be disabled based on a control logic of the primary controller or an instruction delivered by the vehicle driver.

The vehicle control unit is further configured to obtain a load of the motor, and send a control instruction to the primary controller based on the load.

The primary controller is further configured to control a quantity of working DC-AC circuits based on the control instruction, and the quantity of working DC-AC circuits is positively correlated with the load. In other words, as the load increases, more DC-AC circuits are gradually put into operation.

When it is determined that a motor winding is faulty, the primary controller is further configured to control a DC-AC circuit corresponding to the faulty winding to stop working, implementing fault isolation.

In conclusion, according to the method provided in this embodiment of this application, when it is determined that a battery module is faulty, a DC-AC circuit corresponding to the faulty battery module stops working, to reduce impact caused by the fault and implement fault isolation. In addition, a DC-AC circuit corresponding to a battery module that works normally can be controlled to continue working, so that the battery module that works normally can continue to supply power to an electric vehicle. In this way, the vehicle can continue to travel, facilitating vehicle rescue. Therefore, redundancy of the drive system is further improved.

Electric Vehicle Embodiment

Based on the power system provided in the foregoing embodiment, an embodiment of this application further provides an electric vehicle. The following provides descriptions with reference to the accompanying drawing.

Refer toFIG.14.FIG.14is a schematic diagram of an electric vehicle according to an embodiment of this application.

An electric vehicle1400provided in this embodiment of this application includes a power system300. The power system300includes a power battery pack, a drive system, and a motor.

The drive system is configured to drive windings of the motor.

The power battery pack includes at least two battery modules that are independent of each other. The battery modules one-to-one correspond to DC-AC circuits. That is, as shown in the figure, each battery module corresponds to one DC-AC circuit, and each DC-AC circuit corresponds to one winding of the motor. A quantity of the battery modules is the same as a quantity of the DC-AC circuits.

Output voltages of the battery modules may be equal or not equal. In other words, quantities of batteries included in the battery modules may be equal or not equal. This is not limited in this embodiment of this application.

The drive system further includes at least two DC-AC circuits.

The DC-AC circuit is configured to convert a direct current provided by the corresponding battery module into an alternating current to drive a winding of the motor.

For descriptions of the drive system, refer to the foregoing drive system embodiments. Details are not described herein again in this embodiment.

The motor is configured to supply power to a load. The motor includes N windings, and a quantity of phases of each of the N windings may be 2 or 3. That is, the motor may include N two-phase windings or N three-phase windings. This is not limited in this embodiment of this application. N is an integer greater than or equal to 2.

Each winding of the motor is correspondingly connected to an output end of one DC-AC circuit.

In conclusion, the electric vehicle provided in this embodiment of this application includes a power system. A power battery pack corresponding to a drive system of the power system includes at least two battery modules that are independent of each other. The drive system includes at least two DC-AC circuits, and the battery modules one-to-one correspond to the DC-AC circuits. In other words, a quantity of the battery modules is the same as a quantity of the DC-AC circuits. Each battery module is correspondingly connected to an input end of one DC-AC circuit, and an output end of each DC-AC circuit is correspondingly connected to one winding of the motor, that is, the DC-AC circuits one-to-one correspond to each winding of the motor. A quantity of phases of each winding of the motor may be 2 or 3. The DC-AC circuit can convert a direct current provided by the corresponding battery module into an alternating current to drive a winding of the motor. In the solutions of this application, the power battery pack is divided into battery modules that are independent of each other, and each battery module supplies power to a winding of the motor by using a DC-AC circuit corresponding to the battery module. Therefore, when a battery module is faulty, normal power supply by another battery module is not affected, and the other battery module that supplies power normally can continue to supply power to a corresponding motor winding.

The drive system can further control a quantity of working DC-AC circuits based on a load of the motor. That is, a quantity of battery modules that supply power can be selected based on a scenario in which an electric vehicle is located. This reduces energy consumption and prolongs an endurance mileage of the power battery pack. A type of the controllable switching transistor described in this application may be any one of the following: a relay, an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), a SiC MOSFET (carbide field-effect transistor), or the like. This is not limited in embodiments of this application.

It should be understood that in this application, “at least one (item)” refers to one or more and “a plurality of” refers to two or more. The term “and/or” is used to describe an association relationship between associated objects, and indicates that three relationships may exist. For example, “A and/or B” may indicate the following three cases: Only A exists, only B exists, and both A and B exist, where A and B may be singular or plural. The character “/” usually indicates an “or” relationship between the associated objects. At least one of the following items (pieces) or a similar expression thereof refers to any combination of these items, including any combination of singular items (pieces) or plural items (pieces). For example, at least one of a, b, or c may indicate a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural.

The foregoing descriptions are merely example embodiments of this application, and are not intended to limit this application in any form. Although the example embodiments of this application are disclosed above, the embodiments are not intended to limit this application. By using the method and the technical content disclosed above, any person skilled in the art can make a plurality of possible changes and modifications on the technical solutions of this application, or amend the technical solutions thereof to be embodiments with equal effects through equivalent variations without departing from the protection scope of the technical solutions of this application. Therefore, any simple amendment, equivalent variation, and modification made on the above embodiments according to the technical essence of this application without departing from the content of the technical solutions of this application shall fall within the protection scope of the technical solutions of this application.