Power supply system

Abstract

To suppress a relatively large deviation between a charging current of a first battery and a charging current of a second battery during parallel charging.SOLUTION: The power supply system includes a first battery and a second battery, a motor having a three phase coil, a first inverter connected to the first battery via a first positive electrode line and a negative electrode line and connected to one end side of the three phase coil, a second inverter connected to the second battery via a second positive electrode line and the negative electrode line and connected to the other end side of the three phase coil, a charging connector connected to the first positive electrode line and the negative electrode line and electrically connectable to a charging facility, and a controller configured to fix an upper arm of one of the first inverter and the second inverter to an ON state and perform duty control on an upper arm and a lower arm of the other during parallel charging in which the first battery and the second battery are charged using electric power from the charging facility.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to power supply systems. [Background technology]

[0002] Conventionally, a power supply system has been proposed that includes a storage battery device having a first battery and a second battery and a switching relay that can switch between a first state in which the first battery and the second battery are connected in series and a second state in which the second battery are connected in parallel, and an inlet connected to a positive line and a negative line that connect the storage battery device and a PCU that drives a motor (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-118221 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, power supply systems have been devised that include a first battery, a second battery, and a charging connector, and that are capable of parallel charging, in which the first battery is charged via a first charging path and the second battery is charged via a second charging path using power from a charging facility connected to the charging connector.In such power supply systems, there is a possibility that the charging current of the first battery and the charging current of the second battery will differ relatively significantly during parallel charging.

[0005] The power supply system of the present disclosure has as its main objective to prevent a relatively large deviation between the charging current of the first battery and the charging current of the second battery during parallel charging. [Means for solving the problem]

[0006] The power supply system of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The power supply system of the present disclosure comprises: A power supply system including a first battery and a second battery, a motor having a three-phase coil; a first inverter connected to the first battery via a first positive line and a negative line and connected to one end of the three-phase coil; a second inverter connected to the second battery via a second positive line and the negative line and connected to the other end of the three-phase coil; a charging connector connected to the first positive electrode line and the negative electrode line and electrically connectable to a charging device; a control device that fixes an upper arm of one of the first inverter and the second inverter to on and duty controls the upper arm and lower arm of the other inverter during parallel charging in which the first battery and the second battery are charged using power from the charging equipment; The gist of the project is to provide the following:

[0008] The power supply system disclosed herein includes a motor with a three-phase coil, a first inverter connected to a first battery via first positive and negative lines and connected to one end of the three-phase coil, a second inverter connected to a second battery via second positive and negative lines and connected to the other end of the three-phase coil, and a charging connector connected to the first positive and negative lines and electrically connectable to a charging facility. During parallel charging, in which the first and second batteries are charged using power from the charging facility, the upper arm of one of the first and second inverters is fixed on (the lower arm is fixed off), while the upper and lower arms of the other inverter are duty-controlled. Therefore, power from the charging facility can be stepped down by the first inverter and motor and supplied to the second battery, or stepped up by the motor and second inverter and supplied to the second battery. By appropriately controlling the first and second inverters, a relatively large discrepancy between the charging current of the first battery and the charging current of the second battery can be reduced.

[0009] In the power supply system of the present disclosure, during the parallel charging, the control device may set the common required power of the first battery and the second battery to the minimum of the first allowable input power of the first battery and the second allowable input power of the second battery, set the total required power to twice the common required power, request the total required power or a total required current based on the total required power from the charging equipment, and control the first inverter and the second inverter using the common required power or a current command for the second battery based on the common required power. This more appropriately prevents a relatively large deviation between the charging current of the first battery and the charging current of the second battery.

[0010] In the power supply system of the present disclosure, during the parallel charging, if the voltage of the first battery is higher than the voltage of the second battery, the control device may fix the upper arm of the second inverter on (fix the lower arm off) and duty control the upper and lower arms of the first inverter, and if the voltage of the first battery is lower than the voltage of the second battery, fix the upper arm of the first inverter on (fix the lower arm off) and duty control the upper and lower arms of the second inverter. This makes it possible to more appropriately prevent a relatively large difference between the charging current of the first battery and the charging current of the second battery.

[0011] In the power supply system of the present disclosure, the positive terminal of the first battery is connected to the first positive line, and the negative terminal of the second battery is connected to the negative line, and the power supply system further includes a series line connecting the negative terminal of the first battery and the positive terminal of the second battery, a series relay attached to the series line, a parallel line connecting the first battery side of the series relay to the negative line, a first parallel relay attached to the parallel line, and a second parallel relay attached to the second positive line, and during the parallel charging, the series relay is turned off and the first parallel relay and the second parallel relay are turned on, thereby connecting the first battery and the second battery in parallel as viewed from the charging connector, and charging the first battery and the second battery using power from the charging equipment. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram of a power supply system 10 and a charging stand 80 according to an embodiment of the present disclosure. [Figure 2] FIG. 4 is an explanatory diagram showing the flow of current during parallel charging. [Figure 3] 4 is a flowchart showing an example of a processing routine executed by a system ECU 50. DETAILED DESCRIPTION OF THE INVENTION

[0013] A mode (embodiment) for carrying out the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of a power supply system 10 and a charging stand 80 according to an embodiment of the present disclosure. The power supply system 10 is mounted on an electric vehicle or a hybrid vehicle and includes a battery 12, a motor 20, a first inverter 22, a second inverter 24, a switching circuit 30, a charging circuit 40, and a system electronic control unit (hereinafter referred to as "system ECU") 50 as a control device. The power supply system 10 is capable of charging the battery 12 using electric power from a charging stand 80 installed at a home, a charging station, or the like.

[0014] The battery 12 includes a first battery 13 and a second battery 14 as a first cell and a second battery. The first battery 13 and the second battery 14 are configured as, for example, lithium-ion secondary batteries or nickel-metal hydride secondary batteries whose rated voltages are slightly lower than the first voltage Vs1 (e.g., 400 V), respectively. In this embodiment, the first battery 13 and the second battery 14 have the same specifications. The positive terminal of the first battery 13 is connected to a first positive line 31, and the negative terminal of the second battery 14 is connected to a negative line 33. The negative terminal of the first battery 13 is connected to the positive terminal of the second battery 14 via a series line 35. A series relay Rs is attached to the series line 35. Therefore, by turning on the series relay Rs, the first battery 13 and the second battery 14 are connected in series to each other.

[0015] The motor 20 is configured as a three-phase AC motor having, for example, a rotor with a permanent magnet embedded in a rotor core and a stator with three-phase (U-phase, V-phase, W-phase) coils wound around a stator core. The first inverter 22 includes six transistors T11 to T16 as switching elements and six diodes D11 to D16 connected in parallel to the six transistors T11 to T16, respectively. The transistors T11 to T16 are arranged in pairs, two at a time, on the source side and two at the sink side of a first positive line 31 and a negative line 33. Each of the connection points of two transistors in a pair of the transistors T11 to T16 is connected to one end of the three-phase (U-phase, V-phase, W-phase) coils of the motor 20. A first smoothing capacitor 26 is connected to the first positive line 31 and the negative line 33. Like the first inverter 22, the second inverter 24 includes six transistors T21 to T26 as switching elements and six diodes D21 to D26. The transistors T21 to T26 are arranged in pairs, two at a time, on the source side and two at the sink side of a second positive line 32 and a negative line 33. The connection points of two transistors in each pair of the transistors T21 to T26 are connected to the other ends of the three-phase (U-phase, V-phase, W-phase) coils of the motor 20. A second smoothing capacitor 28 is connected to the second positive line 32 and the negative line 33. Hereinafter, the transistors T11 to T13 and T21 to T23 of the first and second inverters 22 and 24 may be referred to as the "upper arm," and the transistors T14 to T16 and T24 to T26 may be referred to as the "lower arm."

[0016] The switching circuit 30 includes a parallel line 36, a first parallel relay Rp1, and a second parallel relay Rp2 in addition to the first positive line 31, second positive line 32, negative line 33, series line 35, and series relay Rs described above. The parallel line 36 connects the negative terminal of the first battery 13 to the negative line 33. The first parallel relay Rp1 is attached to the parallel line 36. The second parallel relay Rp2 is attached to the second positive line 32.

[0017] The charging circuit 40 includes a charging line 42 connected to the first positive electrode line 31 and the negative electrode line 33, and a charging connector 44 connected to the charging line 42. The charging connector 44 is configured to be connectable to a stand connector 82 of the charging stand 80.

[0018] The system ECU 50 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, various drive circuits, and various logic ICs. The system ECU 50 receives signals from various sensors, including a voltage sensor 13v that detects the voltage Vb1 of the first battery 13, a temperature sensor 13t that detects the temperature Tb1 of the first battery 13, a voltage sensor 14v that detects the voltage Vb2 of the second battery 14, and a temperature sensor 14t that detects the temperature Tb2 of the second battery 14. Other sensors include a rotational position sensor 20a that detects the rotational position of the rotor of the motor 20, current sensors 20u, 20v, and 20w that detect currents Iu, Iv, and Iw flowing through the respective phases (U-phase, V-phase, and W-phase) of the motor 20, a voltage sensor 26v that detects the voltage VH of the first capacitor 26, and a voltage sensor 28v that detects the voltage VL of the second capacitor 28. Further examples include a current sensor 31i that detects a current Ip1 flowing through the first positive line 31 and a current sensor 32i that detects a current Ip2 flowing through the second positive line 32. When the series relay Rs is in the OFF state and the first parallel relay Rp1 and the second parallel relay Rp2 are in the ON state, that is, when the first battery 13 is connected to the first positive line 31 and the negative line 33 and the second battery 14 is connected to the second positive line 32 and the negative line 33, the current Ip1 flowing through the first positive line 31 is equal to the current flowing through the first battery 13, and the current Ip2 flowing through the second positive line 32 is equal to the current flowing through the second battery 14. Furthermore, when the series relay Rs is in the on state and the first parallel relay Rp1 and the second parallel relay Rp2 are in the off state, i.e., when the first battery 13 and the second battery 14 are connected in series, the current Ip1 flowing through the first positive line 31 is equal to the current flowing through the first battery 13 and the second battery 14.

[0019] The system ECU 50 calculates the power storage percentages SOC1 and SOC2, open circuit voltages OCV1 and OCV2, and allowable input powers Win1 and Win2 of the first battery 13 and the second battery 14. The power storage percentages SOC1 and SOC2 are calculated based on, for example, the integrated value of the current Ip1 (current flowing to the first battery 13) flowing through the first positive line 31 and the integrated value of the current Ip2 (current flowing to the second battery 14) flowing through the second positive line 32 when the series relay Rs is in the OFF state and the first parallel relay Rp1 and the second parallel relay Rp2 are in the ON state, and the integrated value of the current Ip1 (current flowing to the first battery 13 and the second battery 14) flowing through the first positive line 31 when the series relay Rs is in the ON state and the first parallel relay Rp1 and the second parallel relay Rp2 are in the OFF state. The open circuit voltages OCV1, OCV2 are derived, for example, by applying the power storage rates SOC1, SOC2 to a map that is determined in advance by experiments, analysis, machine learning, etc. as the relationship between the power storage rates SOC1, SOC2 and the open circuit voltages OCV1, OCV2. The allowable input powers Win1, Win2 are derived, for example, by applying the power storage rates SOC1, SOC2 and the temperatures Tb1, Tb2 to a map that is determined in advance by experiments, analysis, machine learning, etc. as the relationship between the power storage rates SOC1, SOC2, the temperatures Tb1, Tb2, and the allowable input powers Win1, Win2.

[0020] The system ECU 50 outputs control signals to the first and second inverters 22, 24 and control signals to each relay. The relays include a series relay Rs, a first parallel relay Rp1, and a second parallel relay Rp2. The system ECU 50 is capable of communicating with a station electronic control unit (hereinafter referred to as "station ECU") 86 of the charging station 80.

[0021] The charging stand 80 includes a stand connector 82, a power supply device 84, and a stand ECU 86. The stand connector 82 is configured to be connectable to the charging connector 44 of the power supply system 10. The power supply device 84 is connected to an AC power source such as a household power source or a commercial power source, and is configured to convert AC power from the AC power source into DC power, adjust output power (output voltage and output current), and output the DC power to the stand connector 82. The stand ECU 86, like the system ECU 50, includes a microcomputer. Signals from various sensors are input to the stand ECU 86. Examples of the various sensors include a voltage sensor (not shown) that detects the output voltage Vs of the power supply device 84 and a current sensor (not shown) that detects the output current Is of the power supply device 84. The stand ECU 86 outputs a control signal to the power supply device 84. As described above, the stand ECU 86 is capable of communicating with the system ECU 50. Examples of charging stations 80 include a first voltage station where the voltage of the supplied power is a first voltage Vs1 (e.g., 400 V), a second voltage station where the voltage of the supplied power is a second voltage Vs2 (e.g., 800 V) that is higher than the first voltage Vs1, and a third voltage station where the voltage of the supplied power can be selectively set to either the first voltage Vs1 or the second voltage Vs2.

[0022] In the power supply system 10 of this embodiment configured as described above, when the vehicle is traveling using the motor 20 as a traction motor, the series relay Rs is turned on and the first parallel relay Rp1 and the second parallel relay Rp2 are turned off, thereby connecting the first battery 13 and the second battery 14 in series, and the motor 20 is driven by the first inverter 22 using power from the first battery 13 and the second battery 14.

[0023] In addition, in the power supply system 10, when the charging connector 44 and the stand connector 82 of the charging stand 80 are connected, the system ECU 50 selects parallel charging if the voltage of the power supplied by the charging stand 80 is a first voltage Vs1, and selects series charging if the voltage of the power supplied by the charging stand 80 is a second voltage Vs2.

[0024] In parallel charging, the first battery 13 and the second battery 14 are connected in parallel from the charging connector 44 by turning the series relay Rs off and turning the first parallel relay Rp1 and the second parallel relay Rp2 on, and the first battery 13 and the second battery 14 are charged using power from the charging stand 80. FIG. 2 is an explanatory diagram showing the flow of current during parallel charging. In the figure, a thick solid line with an arrow indicates the charging current for the first battery 13, and a thick dashed line with an arrow indicates the charging current for the second battery 14. In parallel charging, the first battery 13 is charged by current that flows from the charging connector 44 through the positive line of the charging line 42, the first positive line 31, the first battery 13, the parallel line 36 (first parallel relay Rp1), the negative line 33, the negative line of the charging line 42, and the charging connector 44 in this order, as shown by the thick solid line with an arrow in FIG. 2. 2, the second battery 14 is charged by a current that flows in this order from the charging connector 44 through the positive line of the charging line 42, the first positive line 31, the first inverter 22, the motor 20, the second inverter 24, the second positive line 32 (second parallel relay Rp2), the second battery 14, the negative line 33, the negative line of the charging line 42, and the charging connector 44. At this time, by fixing the upper arm of the second inverter 24 to ON (fixing the lower arm to OFF) and executing step-down control that duty-controls the upper arm and lower arm of the first inverter 22, the motor 20 and the first inverter 22 function as a three-phase step-down converter, and the input power of the first inverter 22 is stepped down and output from the motor 20. In addition, by fixing the upper arm of the first inverter 22 on (fixing the lower arm off) and performing boost control that duty controls the upper arm and lower arm of the second inverter 24, the motor 20 and the second inverter 24 function as a three-phase boost converter, and the input power of the motor 20 is boosted and output from the second inverter 24.

[0025] In series charging, the first battery 13 and the second battery 14 are connected in series by turning on the series relay Rs and turning off the first parallel relay Rp1 and the second parallel relay Rp2, and the first battery 13 and the second battery 14 are charged using power from the charging stand 80. In series charging, the first battery 13 and the second battery 14 are charged by current that flows from the charging connector 44 through the positive line of the charging line 42, the first positive line 31, the first battery 13, the series line 35 (series relay Rs), the second battery 14, the negative line 33, the negative line of the charging line 42, and the charging connector 44 in this order.

[0026] Next, the operation of the power supply system 10 according to the embodiment, particularly the operation during parallel charging, will be described. Fig. 3 is a flowchart showing an example of a processing routine executed by the system ECU 50. This routine is executed repeatedly during parallel charging. Before the repeated execution of this routine begins, the series relay Rs is set to the OFF state, and the first parallel relay Rp1 and the second parallel relay Rp2 are set to the ON state.

[0027] 3 is executed, the system ECU 50 first sets the minimum value of the allowable input powers Win1, Win2 of the first battery 13 and the second battery 14 as a common required power Pb*, which is a required power common to the first battery 13 and the second battery 14 (step S100). Next, the system ECU 50 sets twice the common required power Pb* as an overall required power Pt* (step S110), and sets an overall required current It* based on the set overall required power Pt* and transmits it to the stand ECU 86 of the charging stand 80 (step S120). The overall required current It* is calculated, for example, by dividing the overall required power Pt* by the output voltage Vs of the power supply device 84, or by dividing the overall required power Pt* by the maximum value of the voltages Vb1, Vb2 of the first battery 13 and the second battery 14. When the station ECU 86 receives the total required current It*, it controls the power supply device 84 so that a current equivalent to the total required current It* is supplied from the charging station 80 to the power supply system 10 .

[0028] Then, a current command Ib2* for the second battery 14 is set based on the common required power Pb* (step S130), and the first inverter 22 and the second inverter 24 are controlled based on the set current command Ib2* for the second battery 14 (step S140), after which this routine ends. The current command Ib2* is calculated, for example, by dividing the common required power Pb* by the voltage Vb2 of the second battery 14. By controlling the first inverter 22 and the second inverter 24 in this way, the second battery 14 is charged with a current equivalent to the current command Ib2* (power equivalent to the common required power Pb*) out of the current equivalent to the total required current It* from the charging stand 80 (power equivalent to the total required power Pt*, i.e., power equivalent to twice the common required power Pb*), and the first battery 13 is also charged with the same current. Therefore, it is possible to prevent a relatively large difference between the charging current of the first battery 13 (current Ip1 flowing through the first positive line 31) and the charging current of the second battery 14 (current Ip2 flowing through the second positive line 32).

[0029] The first inverter 22 and the second inverter 24 are controlled, for example, as follows. When the open-circuit voltage OCV1 of the first battery 13 is higher than the open-circuit voltage OCV2 of the second battery 14, step-down control is performed. As a result, a portion of the power from the charging stand 80 is stepped down by the first inverter 22 and the motor 20 and supplied to the second battery 14, thereby preventing a relatively large discrepancy between the charging current of the first battery 13 and the charging current of the second battery 14. When the open-circuit voltage OCV1 of the first battery 13 is lower than the open-circuit voltage OCV2 of the second battery 14, step-up control is performed. As a result, a portion of the power from the charging stand 80 is stepped up by the motor 20 and the second inverter 24 and supplied to the second battery 14, thereby preventing a relatively large discrepancy between the charging current of the first battery 13 and the charging current of the second battery 14. When the open-circuit voltage OCV1 of the first battery 13 and the open-circuit voltage OCV2 of the second battery 14 are equal, either step-down control or step-up control may be performed, or both upper arms of the first inverter 22 and the second inverter 24 may be fixed on (both lower arms may be fixed off). In the latter case, a portion of the power from the charging stand 80 is supplied to the second battery 14 without being voltage-converted by the first inverter 22, the motor 20, and the second inverter 24, thereby preventing a relatively large discrepancy between the charging current of the first battery 13 and the charging current of the second battery 14. Note that the voltage Vb1 of the first battery 13 and the voltage Vb2 of the second battery 14 may be used instead of the open-circuit voltage OCV1 of the first battery 13 and the open-circuit voltage OCV2 of the second battery 14.

[0030] In the power supply system 10 of the embodiment described above, during parallel charging, basically, step-down control is performed by fixing the upper arm of the second inverter 24 on (fixing the lower arm off) and duty-controlling the upper and lower arms of the first inverter 22, or step-up control is performed by fixing the upper arm of the first inverter 22 on and duty-controlling the upper and lower arms of the second inverter 24. Specifically, the minimum value of the allowable input powers Win1 and Win2 of the first and second batteries 13 and 14 is set as the common required power Pb* of the first and second batteries 13 and 14, and twice the set common required power Pb* is set as the total required power Pt*. A total required current It* based on the total required power Pt* is requested from the charging stand 80, and step-down control or step-up control is performed using a current command Ib2* for the second battery 14 based on the common required power Pb*. This control prevents a relatively large discrepancy between the charging current of the first battery 13 and the charging current of the second battery 14.

[0031] In the above-described embodiment, during parallel charging, step-down control or step-up control is performed based on the magnitude relationship between the open-circuit voltage OCV1 of the first battery 13 and the open-circuit voltage OCV2 of the second battery 14 or the magnitude relationship between the voltage Vb1 of the first battery 13 and the voltage Vb2 of the second battery 14. However, in addition to either of these, step-down control or step-up control may also be performed based on at least one of the path impedances of the charging path of the first battery 13 (see the thick solid line with arrow in FIG. 2 ) and the charging path of the second battery 14 (see the thick dashed line with arrow in FIG. 2 ), and the current or power from the charging stand 80. This more appropriately prevents a relatively large difference between the charging current of the first battery 13 and the charging current of the second battery 14. The current from the charging stand 80 during parallel charging may be calculated based on the charging current of the first battery 13 (current Ip1 flowing through the first positive electrode line 31) and the charging current of the second battery 14 (current Ip2 flowing through the second positive electrode line 32), or may be obtained by communication from the stand ECU 86. The power from the charging stand 80 during parallel charging may be calculated based on the charging power of the first battery 13 and the charging power of the second battery 14, or may be obtained by communication from the stand ECU 86. The charging power of the first battery 13 may be calculated as the product of the voltage Vb1 and the current Ip1 of the first battery 13, and the charging power of the second battery 14 may be calculated as the product of the voltage Vb2 and the current Ip2 of the second battery 14.

[0032] In the above-described embodiment, the total required current It* based on the total required power Pt* is transmitted to the station ECU 86 during parallel charging, but this is not limited to this. For example, the total required power Pt* may be transmitted to the station ECU 86 during parallel charging. In this case, upon receiving the total required power Pt*, the station ECU 86 controls the power supply device 84 so that power equivalent to the total required power Pt* is supplied from the charging station 80 to the power supply system 10.

[0033] In the above-described embodiment, during parallel charging, the step-down control or step-up control is performed using the current command Ib2* of the second battery 14 based on the common required power Pb* of the first battery 13 and the second battery 14. However, this is not limiting. For example, the step-down control or step-up control may be performed directly using the common required power Pb* (without using the current command Ib2*).

[0034] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Summary" section will be described. In the embodiment, the first battery 13 corresponds to the "first battery," the second battery 14 corresponds to the "second battery," the motor 20 corresponds to the "motor," the first inverter 22 corresponds to the "first inverter," the second inverter 24 corresponds to the "second inverter," the charging connector 44 corresponds to the "charging connector," and the system ECU 50 corresponds to the "controller." In addition, the series line 35 corresponds to the "series line," the series relay Rs corresponds to the "series relay," the parallel line 36 corresponds to the "parallel line," the first parallel relay Rp1 corresponds to the "first parallel relay," and the second parallel relay Rp2 corresponds to the "second parallel relay."

[0035] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0036] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0037] The present disclosure is applicable to the power supply system manufacturing industry and the like. [Explanation of symbols]

[0038] 10 power supply system, 12 battery, 13 first battery, 13v, 14v, 26v, 28v voltage sensor, 13t, 14t temperature sensor, 14 second battery, 20 motor, 20a rotation position sensor, 20u, 20v, 20w, 31i, 32i current sensor, 22 first inverter, 24 second inverter, 26 first capacitor, 28 second capacitor, 30 switching circuit, 31 first positive line, 32 second positive line, 33 negative line, 35 series line, 36 parallel line, 40 charging circuit, 42 charging line, 44 charging connector, 50 system ECU, 80 charging stand, 82 stand connector, 84 power supply device, 86 stand ECU, D11 to D16, D21 to D26 diode, Rp1 first parallel relay, Rp2 Second parallel relay, Rs series relay, T11~T16, T21~T26 transistors.

Claims

1. A power supply system including a first battery and a second battery, a motor having a three-phase coil; a first inverter connected to the first battery via a first positive line and a negative line and connected to one end of the three-phase coil; a second inverter connected to the second battery via a second positive line and the negative line and connected to the other end of the three-phase coil; a charging connector connected to the first positive electrode line and the negative electrode line and electrically connectable to a charging device; a control device that fixes an upper arm of one of the first inverter and the second inverter to on and duty controls the upper arm and lower arm of the other inverter during parallel charging in which the first battery and the second battery are charged using electric power from the charging equipment; A power supply system comprising:

2. 2. The power supply system of claim 1, During the parallel charging, the control device sets the common required power of the first battery and the second battery to the minimum of the first allowable input power of the first battery and the second allowable input power of the second battery, sets the total required power to twice the common required power, requests the charging equipment to provide the total required power or a total required current based on the total required power, and controls the first inverter and the second inverter using the common required power or a current command for the second battery based on the common required power. Power supply system.

3. 3. The power supply system according to claim 1, During the parallel charging, if the voltage of the first battery is higher than the voltage of the second battery, the control device fixes the upper arm of the second inverter on and duty controls the upper arm and lower arm of the first inverter, and if the voltage of the first battery is lower than the voltage of the second battery, fixes the upper arm of the first inverter on and duty controls the upper arm and lower arm of the second inverter. Power supply system.

4. 3. The power supply system according to claim 1, The positive terminal of the first battery is connected to the first positive line; The negative terminal of the second battery is connected to the negative line; the power supply system further includes a series line connecting the negative terminal of the first battery and the positive terminal of the second battery, a series relay attached to the series line, a parallel line connecting the first battery side of the series relay to the negative line, a first parallel relay attached to the parallel line, and a second parallel relay attached to the second positive line; In the parallel charging, the first battery and the second battery are connected in parallel as viewed from the charging connector by turning the series relay off and turning the first parallel relay and the second parallel relay on, and the first battery and the second battery are charged using power from the charging equipment. Power supply system.

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