PATENT DOCUMENT

Publication Number: US-11456669-B2
Application Number: US-202016988006-A
Country: US
Kind Code: B2

Title: Voltage supply to a load and battery

Abstract:
Implementations described and claimed herein provide systems and methods for supplying voltage to a load and battery. In one implementation, a first regulated DC-to-DC converter is electrically connected to a first energy source to down convert a first voltage supplied by the first energy source. A load is electrically connected to the first regulated DC-to-DC converter to receive the down converted first voltage. A second regulated DC-to-DC converter is electrically connected to the first regulated DC-to-DC converter to regulate the down converted first voltage to a second voltage. A second power source is electrically connected to the second regulated DC-to-DC converter to charge the second power source using the second voltage, and the second power source is switchably connectable to the load.

Claims:
What is claimed is: 
     
       1. An apparatus comprising:
 a first regulated DC-to-DC converter electrically connected to a first energy source to down convert a first voltage supplied by the first energy source into a down converted first voltage, wherein the first energy source is connected in series with the first regulated DC-to-DC converter; 
 a load electrically connected to the first regulated DC-to-DC converter to receive the down converted first voltage, wherein the received down converted first voltage is DC voltage; 
 a second regulated DC-to-DC converter electrically connected in series to the first regulated DC-to-DC converter to regulate the down converted first voltage to a second voltage; and 
 a second energy source electrically connected to the second regulated DC-to-DC converter to charge the second energy source using the second voltage, the second energy source switchably connectable to the load to provide the load with DC voltage, wherein the second energy source is connected in series with the second regulated DC-to-DC converter. 
 
     
     
       2. The apparatus from  claim 1 , wherein the first energy source is a first battery operable at a nominal 800V. 
     
     
       3. The apparatus of  claim 1 , wherein the second energy source is a low voltage battery operable at a nominal 48V. 
     
     
       4. The apparatus of  claim 1 , further comprising a low voltage bus connecting the first regulated DC-to-DC converter to the load. 
     
     
       5. The apparatus of  claim 1 , further comprising a switch electrically connected in parallel with the second regulated DC-to-DC converter, wherein the second energy source connects to the load through the switch to supply the load. 
     
     
       6. The apparatus of  claim 5 , wherein the switch is a MOSFET switch. 
     
     
       7. The apparatus of  claim 5 , wherein the switch supplies power to the load from the second energy source during a failure of the first regulated DC-to-DC converter. 
     
     
       8. The apparatus of  claim 1 , wherein the second regulated DC-to-DC converter is bidirectional, and wherein the second power source provides power to the load through the second regulated DC-to-DC converter. 
     
     
       9. The apparatus of  claim 8 , wherein the power to the load through the second regulated DC-to-DC converter is supplied in conjunction with the down converted first voltage. 
     
     
       10. The apparatus of  claim 1 , further comprising a regulator electrically connected to the load. 
     
     
       11. The apparatus of  claim 1 , wherein the second regulated DC-to-DC converter is a non-isolated buck-boost converter. 
     
     
       12. A method comprising:
 obtaining a first voltage at an input of a first regulated DC-to-DC converter from a first energy source, the first regulated DC-to-DC converter down converting the first voltage to a second voltage, wherein the first energy source is connected in series with the first regulated DC-to-DC converter; 
 supplying the second voltage to a load from the first regulated DC-to-DC converter via a bus, wherein the second voltage supplied to the load is DC voltage; 
 supplying the second voltage to a second regulated DC-to-DC converter, wherein the second regulated DC-to-DC converter is electrically connected in series to the first regulated DC-to-DC converter, wherein the second regulated DC-to-DC converter is operable to provide a charging current to a second energy source, wherein the second energy source is connected in series with the second regulated DC-to-DC converter, wherein the second energy source is switchably connectable to the load to provide the load with DC voltage. 
 
     
     
       13. The method of  claim 12 , wherein the first energy source is a first battery operable at a nominal 800V and the second energy source is a second battery operable at a nominal 48V. 
     
     
       14. The method of  claim 12 , wherein the second regulated DC-to-DC converter is bidirectional, the method further comprising:
 supplying additional power to the load from the second energy source, the additional power provided through the second regulated DC-to-DC converter. 
 
     
     
       15. The method of  claim 12 , further comprising:
 detecting a failure of the first regulated DC-to-DC converter; and 
 activating a switch electrically connected in parallel with the second regulated DC-to-DC converter to power the load using the second power source. 
 
     
     
       16. An apparatus comprising:
 a first regulated DC-to-DC converter with a first input and a second input, the first input of the first regulated DC-to-DC converter is switchably connected in series to a first energy source at a first voltage, wherein the first regulated DC-to-DC converter down converts the first voltage to a second voltage on a bus; 
 a load electrically connected to the bus, wherein the load is configured to receive the second voltage, and wherein the second voltage is DC voltage; 
 a second regulated DC-to-DC converter electrically connected to the bus; 
 a second power source electrically connected in series to the second regulated DC-to-DC converter, the second regulated DC-to-DC converter operable to charge the second power source or to source current from the second power source, wherein the second energy source is switchably connectable to the load to provide the load with DC voltage. 
 
     
     
       17. The apparatus of  claim 16  wherein the second power source is operable to connect to the bus to supplement power to the bus in conjunction with the first regulated DC-to-DC converter or to solely source power on the bus when the first regulated DC-to-DC converter is not powering the bus. 
     
     
       18. The apparatus of  claim 16  wherein:
 the first energy source operates in a range of 650-900 volts DC; 
 the second energy source operates in a range 30-50 volts DC; and 
 the bus operates in a range of 39-54 volts DC. 
 
     
     
       19. The apparatus of  claim 16  wherein the first regulated DC-to-DC converter is 4 Kilowatt and the second regulated DC-to-DC converter is 500 Watts. 
     
     
       20. The apparatus of  claim 16  further comprising a regulator connected between the bus and the load.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is a Continuation-in-part of U.S. Non-provisional patent application Ser. No. 16/012,118, entitled “Converter Architecture,” filed Jun. 19, 2018, which is a continuation of U.S. Non-provisional patent application Ser. No. 15/764,468, entitled “Converter Architecture,” filed Mar. 29, 2018, which is a 371 of PCT Patent Application No. PCT/US2016/053093, filed Sep. 22, 2016, entitled “Converter Architecture,” which claims priority to U.S. Provisional Patent Application No. 62/235,129, entitled “Converter Architecture” and filed on Sep. 30, 2015, the disclosures of which are specifically incorporated by reference in their entireties herein. 
    
    
     TECHNICAL FIELD 
     Aspects of the present disclosure generally involve a converter architecture for supplying voltage to a load and a battery. 
     BACKGROUND 
     Vehicles, including electric or hybrid vehicles, and other devices are generally powered by a high voltage battery or other high energy store. However, such vehicles and devices typically include components or subsystems, such as battery controllers, motor controllers, air conditioning systems, and the like, operating at a relatively lower voltage. Conventionally, a converter down converts the high voltage powering the vehicle or device to the lower voltage at which these components and subsystems operate. 
     SUMMARY 
     In one implementation, a first regulated DC-to-DC converter is electrically connected to a first energy source to down convert a first voltage supplied by the first energy source. The down converted first voltage may be supplied to a bus, and a load is electrically connected to the bus and the first regulated DC-to-DC converter to receive the down converted first voltage. A second regulated DC-to-DC converter is electrically connected to the bus to regulate the down converted first voltage. A second power source is electrically connected to the second regulated DC-to-DC converter to charge the second power source using a down converted second voltage, and the second power source is switchably connectable to the load. Other implementations are described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description will be more fully understood with reference to the following Figures, which are presented as various implementations of the disclosure and should not be construed as a complete recitation of the scope of the disclosure. 
         FIG. 1  is a diagram illustrating an example load voltage supply system using a combination of a first regulated direct current to direct current (DC-to-DC) converter and a second regulated DC-to-DC converter. 
         FIG. 2  is a diagram illustrating a second example load voltage supply system using combination of a first regulated direct current to direct current (DC-to-DC) converter and a second regulated DC-to-DC converter 
         FIG. 2A  is a diagram illustrating the system of  FIG. 2  configured in a recovery operation mode. 
         FIG. 2B  is a diagram illustrating the system of  FIG. 2  configured in an open contactor operation mode. 
         FIG. 2C  is a diagram illustrating the system of  FIG. 2  configured in a low power operation mode. 
         FIG. 2D  is a diagram illustrating the system of  FIG. 2  configured in a high power operation mode. 
         FIG. 2E  is a diagram illustrating the system of  FIG. 2  configured in a DC-to-DC failure operation mode. 
         FIG. 3A  is a timing diagram illustrating bus voltage, low voltage battery voltage and low voltage battery current of the system of  FIG. 2  in various example operational stages. 
         FIG. 3B  is a second timing diagram illustrating bus voltage, low voltage battery voltage and low voltage battery current of the system of  FIG. 2  in various example operational stages. 
         FIG. 4  is a flowchart of example operations for providing a load voltage supply using a combination of a first regulated DC-to-DC converter for powering a bus and a second regulated converter for charging or sourcing current from a low voltage battery system. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the present disclosure involve systems and methods for supplying voltage to a load. In one aspect, a converter, such as a direct current-to-direct current (“DC-to-DC”) converter, converts a relatively higher direct current voltage of a high energy store to a relatively lower direct current voltage utilized by lower voltage loads. For instance, a vehicle or other device typically includes a high energy store, such as a high voltage battery, providing motive current to one or more electric drive motors. The vehicle or device may also include lower voltage components, including, but not limited to, electric power steering systems, navigation systems, dashboard systems, and/or the like, that operate at a lower voltage than the drive motor(s). The lower voltage components are coupled to a low voltage bus that is powered with the high energy store by way of a first regulated DC-to-DC converter. Additionally, the output of the first regulated DC-to-DC converter provides power to a second regulated DC-to-DC converter for charging a low voltage battery, which may nominally operate at the same voltage as the low voltage bus. The second regulated converter provides a regulated voltage to a load/source even as load conditions change on the low voltage battery (or more generally the low voltage bus) and/or input voltages change due to varying inputs at the first regulated converter. The low voltage battery may also power the low voltage components, such as through switchably connecting the low voltage battery to the low voltage bus, if a failure is experienced at the first regulated DC-to-DC converter, or if the low voltage bus is otherwise not powered by the first regulated DC-to-DC converter. 
     To begin a detailed description of an example low voltage supply system  100 , reference is made to  FIG. 1 . In one implementation, the system  100  includes a first regulated DC-to-DC converter  102  connected to a second regulated DC-DC converter  104  and one or more loads  108  via the low voltage bus  110 . The loads  108  may include various components and subsystems operating a low voltage relative to a first energy source  114 , which may be, for example, a high voltage battery. 
     The first energy source  114  may be connected to the first regulated DC-to-DC converter  102  through a contactor  112  that is electrically controlled. It will be appreciated that the first energy source  114  may also provide energy to other systems, including, but not limited to, an electric motor, that operate at a relatively different and typically higher voltage than the loads  108 . 
     The first regulated DC-to-DC converter  102  is the primary source for supplying power to the loads  108  via the low voltage bus  110 . Generally, a DC-to-DC converter may be used to step down voltage, to step up voltage, or to both step up and down voltage. In one implementation, the first regulated DC-to-DC converter  102  receives a high voltage from the first energy source  114  and supplies a sufficient low voltage to the loads  108 . Stated differently, the first regulated DC-to-DC converter  102  down converts the high voltage of the first energy source  114  to a lower voltage suitable for use by the loads  108 . 
     The first regulated DC-to-DC converter  102  may also be a power source for charging the second energy source  116 , such as a low voltage battery. In one implementation, the second energy source  116  is charged and maintained at a nominal voltage and state of charge. The second regulated DC-to-DC converter  104  may be disposed between the first regulated DC-to-DC converter  102  and the second energy source  116  to supply a regulated voltage and charge current to the second energy source  116 . The second regulated DC-to-DC converter  104  compensates for any voltage variances of the low voltage bus  110 , which may occur due to different levels of power drawn by the loads  108 . Supplying a controlled, stable voltage to the second energy source  116  extends a life of the second energy source  116 , assists with charging algorithms, and/or provides other advantages. 
     Because the second regulated DC-to-DC converter  104  may be limited to operating while charging the second energy source  116 , the system may operate more efficiently overall as compared to one with a regulated converter supplying both the loads and low voltage battery. The second regulated DC-to-DC converter  104 , for example, may provide a charge current varying between a level for charging the second energy source  116  from a depleted state to a level maintaining a charge of the second energy source  116  (e.g., a trickle charge). The combination of the first regulated DC-to-DC converter  102  and the second regulated DC-to-DC converter  104  thus increases the efficiency of the system  100 , while providing a regulated output, when needed, to the second energy source  116 . Stated differently, the first regulated DC-to-DC converter  102  provides efficient power to the loads  108  via the low voltage bus  110 , and the second regulated DC-to-DC converter  104  provides regulated output for charging the second energy source  116 . 
     The second regulated DC-to-DC converter  104  further protects the second energy source  116  from transients. As the loads  108  switch on or off or draw varying amounts of power, transient voltages and spikes may be injected onto the bus  110  and cause damage to the second energy source  116  if it were connected directly to the bus. The second regulated DC-to-DC converter  104  is disposed between the bus  110  and the second energy source  116  to regulate the transient voltage variations and thus effectively block them from being absorbed by the second energy source  116 . 
     The first regulated DC-to-DC converter  102  may include high voltage to low voltage DC-to-DC converter or otherwise be associated with a transformer, which dielectrically isolates its input from its output. In some implementations, the first regulated DC-to-DC converter  102  including a high frequency transformer as an isolating barrier protects low voltage electronics, such as the loads  108  and/or the second energy source  116 , from high voltage disturbances that may be transferred from the first energy source  114  or other high voltage systems via the bus  110 . 
     Being connectable to the low voltage bus, the secondary energy source  116  may provide power to the loads  108  in the event of a malfunction of the first regulated DC-to-DC converter  102  or when the first regulated DC-to-DC converter is disabled. Such malfunctions may include, for example, instances where the first regulated DC-to-DC converter  102  fails to provide sufficient voltage to the loads  108 , by way of the low voltage bus  110 . Besides disabling (e.g., turning it off) the first regulated DC-to-DC converter, the first energy source  114  may also not be coupled to the low voltage bus  110  by opening the contactor  112  during some modes of operation. In one possible implementation, a switch  106  directs power from the second energy source  116  to the loads  108  via the low voltage bus  110 . The switch  106  may be any electrical component connecting the second energy source  116  to the low voltage bus  110 , including, but not limited to, a transistor, a relay, a contactor, and the like. The second regulated DC-to-DC converter  104  may also be bi-directional and power to the low voltage bus may be provided through the second regulated DC-to-DC converter  104 . Such may be beneficial when the low voltage battery voltage differs from a nominal bus voltage. 
     Turning to  FIG. 2 , an example load voltage supply and low voltage battery charging system  200  is shown. The system  200  includes a first energy source in the form of a high voltage (“HV”) battery  214  and a second energy source in the form of a low voltage (“LV”) battery  216 . It will be appreciated by those skilled in the art that the terms “high voltage” and “low voltage” reflect a relative relationship between a nominal voltage or operating voltage range of the HV battery  214  and the LV battery  216  and are not intended to imply any particular voltage or range. In one example, high voltage refers to various traction battery voltages for driving an electric motor, and low voltage refers to a voltage or range of voltages for operating one or more loads  210 , such as compressors (e.g., for air conditioning), fans, entertainment systems, and other low voltage vehicle systems. 
     As an example, the HV battery  214  may include a number of low voltage cells coupled in series and/or parallel to achieve an overall battery voltage with an operating range of approximately 650-900 volts of direct current (“VDC”). In one implementation, the LV battery  216  has an operating voltage range that overlaps with an operating voltage range of a LV bus  218  as configured for the loads  210 . For example, the LV battery  216  may have an operating voltage range of approximately 30-50 VDC, and the LV bus  218  may have an operating voltage range of approximately 39-54 VDC. In one example, the HV battery  214  operates at a nominal voltage of approximately 800 VDC, while the LV battery  216  operates at a nominal voltage of approximately 48 VDC. In other examples, the LV battery  216  operates at a nominal voltage of approximately 24 VDC as a relatively lower voltage energy source and at a nominal voltage of approximately 72 VDC as a relatively higher voltage energy source. In still another example, the HV battery  214  has an operating voltage range of approximately 270-450 VDC, while the LV battery  216  operates at a voltage range of approximately 39-54 VDC. It will be appreciated that these voltage values and ranges are exemplary only and other values and ranges are contemplated. 
     In one implementation, to provide efficient power to the loads  210  via the LV bus  218  and provide regulated power to the LV battery  216  for charging, the system  200  includes a first regulated DC-to-DC converter  202  and a second regulated DC-to-DC converter  204 . The first regulated DC-to-DC converter, generally speaking, provides some output depending in part on the input supplied to the converter. In the case of an isolated converter including a transformer with primary and secondary windings, for example, the output voltage will be proportional to the input voltage and depend on the ratio of primary to secondary windings of the transformer. That is to say, if a regulated converter receives an input of 800 VDC, it will provide X volts out. But if the regulated converter is provided 400 VDC, the converter will provide X/2 volts out, instead of trying to regulate its output to a higher value. So, in the specific example of an 800 VDC primary energy source, the windings of the converter may be established to provide an output range of 39-54 VDC based on a high voltage battery range of 650-900 VDC. The loads receiving power from the low voltage bus thus are those that can operate in that range. The low voltage battery, however, may not be able to properly charge if an insufficient input voltage is provided. For example, a 48 V low voltage battery may not charge with a 39 VDC input voltage. Hence, the second regulated converter is able to provide a regulated voltage sufficient for charging the battery, and able to provide a regulated voltage addressing the range of possible voltages on the low voltage bus. So, for example, when charging a 48 V low voltage battery, slightly greater than 48 V may be required and the second regulated DC-to-DC converter may need to be able to supply that voltage based on low voltage bus range of 39-54 V DC. 
     The DC-to-DC converters may be isolated or non-isolated and include buck converters, boost converters, buck-boost converters, Cuk converters, charge-pump converters, and/or the like depending on whether the converted voltage is stepped up, stepped down, both, and/or inverted. The first regulated DC-to-DC converter  202  may be a buck converter that reduces the voltage of the HV battery  214  to a lower voltage value or range for the components connected to the LV bus  218 . The second regulated DC-to-DC converter  204  may also be a buck type converter to further step-down the voltage across the LV bus  218  to a voltage for charging or maintaining the LV battery  216 , for instance where the operational voltage of the LV battery  216  is lower than the operational voltage of the loads  210 . As a buck converter, the first regulated DC-to-DC converter  202  and the second regulated DC-to-DC converter  204  may include an inductor, a transistor and/or a diode configured in a buck arrangement. 
     In another example where a nominal voltage of the LV battery  216  is higher than the voltage across the LV bus  218 , the second regulated DC-to-DC converter  204  may be a boost type converter, which increases the voltage output from the first regulated DC-to-DC converter  202 . In yet another example, the second regulated DC-to-DC converter  204  is a buck-boost converter. A buck-boost converter provides buck or boost functionality to decrease or increase the bus voltage, respectively, depending on the low voltage bus voltage and the demands of the LV battery  216  and/or the loads  210  in various operational modes, as discussed in more detail herein. The second regulated DC-to-DC converter  204  configured as a buck-boost converter further provides bidirectional functionality, such that power may be directed from the LV bus  218  to the LV battery  216  or directed from the LV battery  216  to the LV bus  218 . 
     In one particular implementation, the first regulated DC-to-DC converter  202  is a 4 kW isolated DC-to-DC buck converter, and the second regulated DC-to-DC converter  204  is a 500 W non-isolated bidirectional buck-boost converter. The combination of the first regulated DC-to-DC converter  202  and the second regulated DC-to-DC converter  204  in this implementation provides the system  200  with a η=97-98% conversion efficiency. 
     As described herein, a regulated voltage is provided to the loads  210  via the LV bus  218 . In one implementation, one or more of the loads  210  may utilize a regulated voltage. Thus, a regulator  206  may be operably positioned between the LV bus  218  and such load(s)  210  to provide a regulated voltage. The regulator  206  may also operate like a regulated converter, compensating the voltage provided to one or more of the loads  210  where the voltage powering the load  210  is greater than the low voltage rail on the LV bus  218 . Those of ordinary skill will recognize that the regulator  206  may be a discrete component or integrated with one or more of the loads  210 . In the case of a discrete component, the regulator  206  may be shared among the loads  210  or specific to a particular load  210 . 
     A switch  208 , such as a metal oxide semiconductor field effect transistor (MOSFET), may be deployed between the LV battery  216  and the LV bus  218 . The switch  208  selectively supplies power to the loads  210  from the LV battery  216 . For example, the switch  208  may direct power to the loads  210  from the LV battery  216  when: the HV battery  214  is unavailable to supply power (e.g., when a HV contactor  212  is open); the HV battery  214  and/or the first regulated DC-to-DC converter  202  malfunctions; and, the power supplied by the HV battery  214  needs to be supplemented. 
     As can be understood from  FIGS. 2A-2E  and  FIGS. 3A-3B , the system  200  may be deployed in a vehicle and converted to implement various operation modes.  FIG. 2A-2E  illustrate a recovery operational mode  220 , a contactor open operational mode  230 , a low power use operational mode  240 , a high power use operational mode  260 , and a DC-to-DC failure operational mode  280 , respectively. The system  200  controls the current flow from the HV battery  214  and to and from the LV battery  216  during these operational modes using one or more switches, converters, and/or the like.  FIGS. 3A and 3B  show timing diagrams  300  and  350  and illustrate voltages (Vbatt  318  shown in dashed lines) and currents (Ibatt  322  shown in solid lines) for the LV battery  216  and voltages (Vbus  320  shown in broken lines) for the LV bus  218 , among other information associated with each of these operational modes and transitions among the same.  FIG. 3B  further illustrates a voltage supply of the LV battery  216  and across the LV bus  218  during these operational modes, with the LV battery  216  providing at least some of the voltage supply to the loads  210  to supplement or replace the HV battery  214  power during the high power use operational mode. It will be appreciated that these operational modes and the information and transitions associated therewith are exemplary only and not intended to be limiting. 
     Turning first to  FIG. 2A , in one implementation, the system  200  is configured for the recovery operational mode  220 , wherein a charge state of the LV battery  216  is depleted or otherwise below a nominal level. For example, the system  200  includes one or more loads  210 , such as an air conditioning system, entertainment system, navigation system, and/or other vehicle subsystems or components. If the loads  210  operate for any extended time while only drawing power from the LV battery  216 , the LV battery  216  may become depleted. In the recovery operational mode  220 , the system  200  recharges the LV battery  216  until the charge state reaches the nominal level. 
     In one implementation, in the recovery operational mode  220 , the HV contactor  212  is CLOSED, the first regulated DC-to-DC converter  202  and the second regulated DC-to-DC converter  204  are ON, and the switch  208  is OFF. In this configuration, DC voltage is supplied from the HV battery  214  to the first regulated DC-to-DC converter  202 . The DC voltage is then supplied from the first regulated DC-to-DC converter  202  to provide a change current in a first direction  222  to the second regulated DC-to-DC converter  204  to charge the LV battery  216 . The DC voltage is further supplied from the first regulated DC-to-DC converter  202  along the LV bus  218  to provide a load current  224  the loads  210 . 
     Referring to  FIGS. 2A and 3A  together, the timing diagram  300  includes recovery operational mode values  306  associated with the implementation of the system  200  in the recovery operational mode  220 . As shown in  FIG. 3A , the Vbatt  318  is in a low charge state below a nominal level  328  and an operational voltage range  302  for the LV battery  216 . During the recovery operational mode  220 , the Vbatt  318  increases as the charge state is recovered for the LV battery  216 . For example, the Vbatt  318  may increase until the nominal level  328  is reached. The Vbatt  318  may be monitored until the charge state is reached. 
     The Ibatt  322  may be initially low during the recovery operational mode  220  to reduce a risk of any damage to the LV battery  216  in the low charge state. In the implementation shown in  FIG. 3A , the Ibatt  322  jumps to a higher current level where it remains until the LV battery  216  is recharged to the appropriate level. The Ibatt  322  thus corresponds in this case to the Vbatt  318  during the recovery operational mode  220 . Once the charge state is achieved, the Ibatt  322  decreases to a lower value where power is supplied to the LV battery  216  during a trickle or maintenance state. The Vbus  320  in the recovery operational mode values  306  depicts a voltage ramp indicative of no additional loads drawing power from the LV bus  218  during the recovery operational mode  220 . The Vbus  320  may increase through an upper bound of a voltage range  304  of the LV bus  218 . 
     Referring to  FIGS. 2A and 3B , in another implementation of the recovery operational mode  220 , the HV contact  212  is CLOSED and both the second regulated DC-to-DC converter  204  and the first regulated DC-to-DC  202  are ON, thereby directing current from the LV bus  218  to the LV battery  216 . As shown in  FIG. 3B , the Vbatt  318  increases at a stable rate towards the nominal level  328 , with the Ibatt  322  varying. Similar to  FIG. 3A , the Vbus  320  shows a ramp up in the recovery operational mode values  306   
     For a detailed description of the system  200  in the contactor open operational mode  230 , reference is made to  FIG. 2B . In one implementation, the contactor open operational mode  230  includes the HV contactor  212  in an OPEN position with the first regulated DC-to-DC converter  202  and second the regulated DC-to-DC converter  204  OFF. As such, no power is supplied to the loads  210  from the HV battery  214 , and the LV battery  216  is not being recharged or actively maintained with power from the HV battery  214 . Stated differently, no current flow is directed from the HV battery  214  to the LV battery  216  or the loads  210 . The switch  208  may be set to ON, thereby providing power to the loads  210  from the LV battery  216 . 
     Referring to  FIGS. 3A and 3B  in view of  FIG. 2B , an example transition sequence from the recovery operational mode  220  to the contactor open operational mode  230  and an example transition sequence from the low power use operational mode  240  to the contactor open operational mode  230  are illustrated with contactor open operational mode values  314  and  316 , respectively. 
     As discussed above, no current flow is supplied to the LV battery  216  in the contactor open operational mode  230 . The Ibatt  322  thus falls to zero, and depending on a length of time the system  200  is operating in the contactor open operational mode  230  and/or an amount of power drawn from the LV battery  216  by the loads  210 , the Vbatt  318  may similarly decrease. In one implementation, the system  200  selects one of the operational modes  220 ,  240 ,  260  or  280  based on a level of the Vbatt  318  following the contactor open operational mode  230 . For example, if the LV battery  216  is too depleted, the system  200  may select and execute the recovery operational mode  220  prior to some other operational mode. In contrast, if the LV battery  216  is operational, albeit at some state of charge less than 100%, the system  200  may be able to operate in some other operational mode and recharge or use the LV battery  216  accordingly. 
       FIG. 2C  illustrates the system  200  in the low power use mode  240  with only nominal operation occurring to reduce power usage. For example, when the system  200  is deployed in a vehicle, the low power use mode  240  may correspond to instances where the vehicle is parked and thus the only loads  210  ON are those pulling low voltage, such as monitoring memory, sensors, and/or the like. 
     In one implementation of the low power use mode  240 , the HV contactor  212  is CLOSED, the first regulated DC-to-DC converter  202  and the second regulated DC-to-DC converter  204  are ON, and the switch  208  is set to OFF. The HV battery  214  thus provides power to the loads  210  via the LV bus  218 . The HV battery  214  further provides power to maintain the LV battery  216  via the second regulated DC-to-DC converter  204 . As can be understood from  FIGS. 3A and 3B  in connection with  FIG. 2C , in one implementation, the Ibatt  322  is set an initial level and reduced as the Vbatt  318  reaches and remains at the nominal level  328 . At this point, the Vbatt  318  is provided as a trickle charge in a first direction  242  to maintain the LV battery  216  and in a second direction  244  along the LV bus  218  to power the loads  210 . 
     Low power use operational mode values  308  demonstrate that the LV battery  216  and the loads  210  draw little to no power from HV battery  214  via the LV bus  218  during the low power use mode  240 . As such, the Vbatt  318  and the Vbus  320  have values at the upper limit of the operational voltage ranges  302  and  304 , respectively. The operational voltage range  302  of the LV battery  216  may be approximately 39-54 VDC or 30-50 VDC with the upper limit being approximately 50 VDC, and the operational voltage range  304  of the LV bus  218  may be approximately 33-56 VDC, with the Vbus  320  being near 56 VDC during the low power use mode  240 . 
     In one implementation, where the system  200  is transitioning from the contactor open mode  230  to the low power use mode  240  as shown with the contactor open operational mode values  314 , the Ibatt  322  transitions from zero to a charge current that is sustained until the LV battery  216  reaches a charged state, at which time the Ibatt  322  drops. Similarly, the Vbatt  318  increases from a level of the contactor open mode  230  to the nominal level  328 . The level of the contactor open mode  230  may be relatively lower due a gradually decreasing state of charge and some decrease in the voltage of the LV battery  26 . The voltage supplied across the LV bus  218  supplied by the first regulated DC-to-DC converter  202  increases the Vbus  320  to the upper limit of the operational voltage range  304 . 
     Referring to  FIG. 2D , the system  200  is illustrated in the high power use operational mode  260  during which the system  200  is experiencing a high demand from the various low voltage systems, such as the loads  210  and/or the LV battery  216  to recharge it. The system  200  may alternatively or additionally have a high demand on the HV battery  214  by a traction motor or other high voltage systems. 
     In one implementation of the high power use operational mode  260 , the HV contactor  212  is CLOSED, the first regulated DC-to-DC converter  202  and the second regulated DC-to-DC converter  204  are ON, and the switch  208  is OFF. Where the second regulated DC-to-DC converter  204  is bidirectional, the voltage across the LV bus  218  may be supplemented with the LV battery  216 . As such, power for the loads  210  is supplied by the HV battery  214  across the LV bus  218  in a first direction  262 , which is supplemented by power from the LV battery  216  across the second regulated DC-to-DC converter  204  in a second direction  264 . 
     Turning to  FIG. 3A  in the context of  FIG. 2D , the high power use operational mode  260  supplies power to the loads  210  via the LV bus  218 , with the Vbus  320  thus being high. In the example case shown in  FIG. 3A , the low voltage battery is initially somewhat discharged so that besides providing power to the loads, power is also required to provide a charge current iBatt to the low voltage battery, which is decreased when some sufficient state of charge is reached (e.g., 90%). 
     In one implementation, the second regulated DC-to-DC converter  204  contains one or more sensors configured to sense voltage and current levels output for the LV battery  216 . The sensors of the second regulated DC-to-DC converter  204  may create current and voltage loops, which may be used to monitor output impedance for regulating the voltage and current output by the second regulated DC-to-DC converter  204 . For example, a current sensor can be located above the second regulated DC-to-DC converter  204  to create a current loop for monitoring current at an output of the second regulated DC-to-DC converter  204  to determine whether to increase the output of the second regulated DC-to-DC converter  204 . Similarly, the second regulated DC-to-DC converter  204  may also include a voltage sensor located below the second regulated DC-to-DC converter  204  for voltage regulation. The voltage sensor creates a voltage loop back into the second regulated DC-to-DC converter  204  to reduce output impedance by measuring the Vbatt  318  and the Vbus  320 . If the Vbatt  318  is greater than the Vbus  320 , the LV battery  216  discharges on the LV bus  218  by way of the bidirectional second regulated DC-to-DC converter  204  in the second direction  264 . The LV battery  216  thus provides reduced output impedance at the regulator  206 , while maintaining the Vbatt  318  less than or equal to the Vbus  320 . 
     The compensation by the LV battery  216  in the high power use operational mode  260  is illustrated in  FIG. 3B  with the high power use operational mode values  310 . In particular, the high power use operational mode values  310  of  FIG. 3B  show the Vbatt  318  dropping as the LV battery  216  directs voltage through the second regulated DC-to-DC converter  204  to the LV bus  218  as the state of charge of the LV battery  216  depletes, which may be reflected in the voltage of the battery. Because the LV battery  216  is supplementing the voltage across the LV bus  218 , the Ibatt  322  is shown as a negative value meaning it is sourcing current as compared to  FIG. 3A  where the battery is being charged during high power mode. With the Vbatt  318  reaching the lower limit of the operational range  304  (e.g., at or below 50% SOC), the second regulated DC-to-DC converter  204  may be turned OFF so as to not drain the low voltage battery further. 
     For a detailed description of the system  200  operating in the DC-to-DC failure operational mode  280 , reference is made to  FIG. 2E . As described herein, the first regulated DC-to-DC converter  202  may malfunction or otherwise become incapable of powering the loads  210 . DC-to-DC converter failure can occur for numerous reasons and be indicated by a reduction in voltage across the LV bus  218  to below a threshold. During such failures, the LV battery  216  may power the loads  210  while the LV battery  216  has sufficient charge.  FIGS. 3A and 3B  illustrate a scenario where the first regulated DC-to-DC converter fails and the low voltage battery is at a 90% SOC and a 50% SOC, respectively. When such a failure occurs, the low voltage battery is connected to the bus through the switch  208  (ON). As illustrated, iBatt is drawn from the battery and supplies the loads and the length of time that is able to supply the loads will depend on the load being drawn as well as the SOC among other factors. In one implementation of the DC-to-DC failure operational mode  280 , the HV contactor  212  is OPEN, the second regulated DC-to-DC converter  204  is turned OFF, and the switch  208  is turned ON to provide power from the LV battery  216  across the LV bus  218  in a first direction  282  and across the switch  208  in a second direction  284 . 
     For a detailed description of example operations  400  for providing a load voltage supply using a regulated DC-to-DC converter and a low voltage battery system, reference is made to  FIG. 4 . It will be appreciated that the operations  400  may be implemented using the system  100  or  200  and in various operation modes, including but not limited to the operation modes  220 ,  230 ,  240 ,  260 , and  280 , as well as other systems and operation modes. The operations  400  may further be implemented in the context of a vehicle or other device where power is drawn from a high voltage source and converted to provide low voltage to one or more loads or low voltage power sources. 
     In one implementation, an operation  402  obtains a voltage supplied by a first power source, such as a high voltage battery, at an input of a DC-to-DC converter. A contactor, such as a high voltage contactor, may be disposed between the first power source and the DC-to-DC converter to control the flow of voltage from the first power source. The DC-to-DC converter may be unregulated, regulated, isolated, non-isolated, step-up, step-down, inversion, and/or the like. For example, the DC-to-DC converter may be a voltage down converter receiving the voltage supplied by the first power source at the input and outputting a down converted voltage for one or more loads, batteries, and/or other systems operating at the down converted voltage. In another example, the DC-to-DC converter is an isolated unregulated DC-to-DC converter, providing dielectric isolation between the input and an output of the DC-to-DC converter to provide isolation for one or more loads, such as wipers, air conditioning units, lamp lights, dashboards, and/or the like. 
     An operation  404  supplies the down converted voltage to one or more loads via a bus. In addition or alternatively to the operation  404 , an operation  406  supplies the down converted voltage to a second power source, which may be a low voltage battery. In one implementation, the operation  406  supplies the down converted voltage to the second power source via the bus and a regulated DC-to-DC converter. In one implementation, the voltage across the bus ranges from approximately 50% to 90% of a voltage of a second power source, such as a low voltage battery, connected to the bus. In another implementation, a regulator is connected to the bus to increase or otherwise regulate the voltage. For example, where the first power source is a high voltage battery with voltage range of approximately 650-900 VDC, the bus voltage has a voltage range of approximately 39-54 VDC (i.e., 50%-90%). As another example, the first power source is a high voltage battery with voltage range of approximately 270-450 VDC, and the bus voltage has a voltage range of approximately 39-54 VDC. With the use of the regulator in the form of a non-isolated, regulated DC-to-DC converter, the bus may have a change of voltage range of approximately 33-56 VDC, which corresponds to approximately ⅛ of the high voltage of the first power source. Therefore, the voltage on the bus may be higher or lower than the voltage of the second power source, which a range of approximately 30-50 VDC. 
     A second regulated DC-to-DC converter can be operable at a lower power than the a first regulated DC-to-DC converter used by the operation  404  to down convert the high voltage provided by the first power source. For example, the operation  404  may utilize a 4 kW DC-to-DC converter to down convert the voltage from the first power source, and the operation  406  may utilize a 500 W non-isolated, regulated DC-to-DC converter to supply power to the second power source for charging. In some implementations, the operation  406  turns the second regulated DC-to-DC converter off when the second power source is not being charged, thereby increasing efficiency of the system. 
     In one implementation, operations  408 - 414  ensure the loads receive adequate voltage for operation by providing a voltage across the bus within an operating range of the loads. The operation  408  senses a voltage across the bus and determines whether the bus voltage is within the operating range of the loads. If the bus voltage drops below the operational range of the loads, the operation  410  may identify a malfunction of the first regulated DC-to-DC converter. The operation  410  may automatically identify an alternate power source, such as the second power source. Once the second power source is identified, the operation  410  enables a switch or bidirectional functionality of the second regulated DC-to-DC converter to connect the second power source to the bus to provide power to the loads. Additionally or alternatively, the operation  410  may use a voltage sensor that triggers the switch to turn ON where the voltage across the bus is low. Once the switch or bidirectional functionality of the second regulated DC-to-DC converter is triggered, the operation  412  supplies voltage to the loads from the second power source via the bus. 
     While the present disclosure has been described with reference to various implementations, it will be understood that these implementations are illustrative and that the scope of the disclosure is not limited to them. Many variations, modifications, additions, and improvements are possible. More generally, implementations in accordance with the present disclosure have been described in the context of particular implementations. Functionality may be separated or combined in blocks differently in various embodiments of the disclosure or described with different terminology. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure as defined in the claims that follow.

Metadata:
Filing Date: 20200807
Publication Date: 20220927
Grant Date: 20220927
Priority Date: 20150930
Inventors: ALVES, Jeffrey M.
WU, PENG
PEREZ, YEHONATAN
LEE, KISUN
Juang, Philip
Assignee: APPLE INC
CPC Classifications: [{"code": "H02M1/007", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L58/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L2210/14", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/156", "inventive": true, "first": true, "tree": "[]"}, {"code": "B60L2210/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L3/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L2210/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/1582", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M3/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M3/156", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02M1/007", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L58/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M1/325", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/33507", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L2210/14", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M1/007", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L58/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M3/1582", "inventive": true, "first": true, "tree": "[]"}, {"code": "B60L2210/14", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L2210/12", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 73230893