Power supply system

Abstract

When power is exchanged between the first and second batteries and the outside via the connector, the current of the second battery is suppressed when the ON-fix control, which fixes the first and second upper arms of the three phases in the ON position, is initiated. [Solution] When the power supply system exchanges power between the first and second batteries and the outside via a connector, it performs duty control to control the first and second inverters by setting the first and second duty commands based on the motor current command and feedback control based on the current. During duty control, when the difference between the current command and the current is less than a first predetermined difference and the first and second duty commands are greater than or equal to a predetermined value, it transitions to on-fix control, which turns on and fixes the three-phase first and second upper arms.

Description

Technical Field

[0001] This disclosure relates to a power supply system.

Background Art

[0002] Conventionally, there has been proposed a power supply system including a battery system having a first battery, a second battery, and a switching relay capable of switching between a first state in which these are connected in series and a second state in which they are connected in parallel, and an inlet connected to a positive electrode wire and a negative electrode wire connecting the battery and a PCU that drives a motor (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, a power supply system has been devised comprising first and second batteries, a motor having a three-phase open winding, a first inverter connected to the first battery via a first positive-side line and a negative-side line, connected to one end of the three-phase open winding, and having a three-phase first upper arm and a first lower arm, a second inverter connected to the second battery via a second positive-side line and a negative-side line, connected to the other end of the three-phase open winding, and having a three-phase second upper arm and a second lower arm, and a connector connected to the first positive-side line and a negative-side line. In this configuration, when power is exchanged between the first and second batteries and the outside via the connector, the second battery exchanges power with the outside via the second inverter, motor, first inverter, and connector, which can cause switching losses in the first and second inverters. To suppress the switching losses of the first and second inverters, it is conceivable to implement on-fix control, which fixes the three-phase first and second upper arms in the ON position, but depending on the timing of its start, the current of the second battery may become erratic.

[0005] The primary purpose of the power supply system disclosed herein is to suppress disturbances in the current of the second battery when power is exchanged between the first and second batteries and the outside via a connector, and when on-fix control is initiated to fix the first and second upper arms of the three phases in the on position. [Means for solving the problem]

[0006] The power supply system disclosed herein employs the following means to achieve the primary objectives described above.

[0007] The power supply system disclosed herein is The first and second batteries, A motor having a 3-phase open winding, A first inverter is connected to the first battery via a first positive electrode line and a first negative electrode line, and is connected to one end of the three-phase open winding, and has a three-phase first upper arm and a first lower arm. A second inverter is connected to the second battery via a second positive electrode line and a second negative electrode line, and is connected to the other end of the three-phase open winding, and has a three-phase second upper arm and a second lower arm. A connector connected to the first positive electrode line and the negative electrode line, A control device for controlling the first and second inverters, A power supply system comprising, When the control device exchanges power between the first and second batteries and the outside via the connector, it sets the first and second duty cycle commands by current command and feedback control based on the current, and performs duty cycle control to control the first and second inverters. During the duty cycle control, when the difference between the current command and the current is less than a first predetermined difference and the first and second duty cycle commands are greater than or equal to a predetermined value, it transitions to on-fix control, which turns the three-phase first and second upper arms on. This is the gist of it.

[0008] In the power supply system of this disclosure, when power is exchanged between the first and second batteries and the outside via a connector, duty control is performed to control the first and second inverters by setting the first and second duty commands based on the motor current command and feedback control based on the current. During duty control, when the difference between the current command and the current is less than a first predetermined difference and the first and second duty commands are greater than or equal to a predetermined value, the system transitions to on-fixed control, which fixes the three-phase first and second upper arms in the on position. This makes it possible to suppress disturbances in the current of the second battery that occur when transitioning from duty control to on-fixed control (start of on-fixed control).

[0009] In the power supply system of this disclosure, the control device may switch to duty cycle control when the difference reaches a second predetermined difference or greater than the first predetermined difference during the ON fixed control.

[0010] In this case, the control device may reset the integral term in the feedback control to a value of 0 when transitioning from the ON fixed control to the duty cycle control.

[0011] In the power supply system of the present disclosure, the control device may also perform the duty cycle control when exchanging power between the first and second batteries via the first inverter, the motor, and the second motor, and may transition to the ON fixed control when the difference is less than the first predetermined difference and the first and second duty cycle commands are greater than or equal to the predetermined value during the duty cycle control. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of the power supply system and charging / powering stand according to the embodiment of the disclosure. [Figure 2] This is an explanatory diagram showing the current flow during parallel charging, one of the parallel charging and power supply methods. [Figure 3] This is a flowchart showing an example of a processing routine. [Modes for carrying out the invention]

[0013] Embodiments for implementing this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of a power supply system 10 and a charging / discharging stand 80 according to an embodiment of this disclosure. As shown in the figure, the power supply system 10 includes a battery 12, a motor 20, first and second inverters 22 and 24, a switching circuit 30, a charging / discharging circuit 40, and a system electronic control unit (hereinafter referred to as "system ECU") 50 (control device). The power supply system 10 is installed in electric vehicles, hybrid vehicles, and fuel cell vehicles. The power supply system 10 is capable of exchanging power between the battery 12 and a charging / discharging stand 80 installed at a home or charging / discharging station.

[0014] Battery 12 comprises first and second batteries 13 and 14 (first and second batteries). The first and second batteries 13 and 14 are configured as lithium-ion secondary batteries or nickel-metal hydride secondary batteries, for example, with a rated voltage of approximately 400V (first voltage Vs1). In this embodiment, the first and second batteries 13 and 14 are configured to have the same specifications. The positive terminal of the first battery 13 is connected to the first positive line 31, and the negative terminal of the second battery 14 is connected to the 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, and a series relay Rs is provided in the series line 35. Therefore, by turning on the series relay Rs, the first and second batteries 13 and 14 are connected in series with each other.

[0015] The motor 20 is configured as a three-phase AC motor and comprises a rotor with permanent magnets embedded in its rotor core and a stator with three-phase (U-phase, V-phase, W-phase) coils (open windings) wound around its stator core. The rotor is connected to a drive shaft which is linked to the drive wheels via a differential gear.

[0016] The first and second inverters 22 and 24 each comprise six transistors T11-T16 and T21-T26, and six diodes D11-D16 and D21-D26 connected in parallel to each of the six transistors T11-T16 and T21-T26. Examples of transistors T11-T16 and T21-T26 include MOSFETs and IGBTs. The transistors T11-T16 and T21-T26 are arranged in pairs, with two transistors acting as the source and two as the sink for the first and second positive-side lines 31 and 32 and the negative-side line 33. Each connection point of a pair of transistors T11-T16 is connected to one end of the three-phase coil of the motor 20. Each connection point of a pair of transistors T21-T26 is connected to the other end of the three-phase coil of the motor 20. Hereafter, transistors T11 to T13 may be referred to as the "first upper arm," transistors T14 to T16 as the "first lower arm," transistors T21 to T23 as the "second upper arm," and transistors T24 to T26 as the "second lower arm."

[0017] The switching circuit 30 includes a first and second positive-side lines 31, 32, a negative-side line 33, a series line 35, a series relay Rs, as well as a parallel line 36, a first parallel relay Rp1, and a second parallel relay Rp2. The first positive-side line 31 connects the positive-side terminal of the first battery 13 to the first three-phase upper arm (transistors T11 to T13) of the first inverter 22. The second positive-side line 32 connects the positive-side terminal of the second battery 14 to the second three-phase upper arm (transistors T21 to T23) of the second inverter 24. The parallel line 36 connects the negative-side terminal of the first battery 13 to the negative-side line 33. The first parallel relay Rp1 is provided on the parallel line 36. The second parallel relay Rp2 is attached to the second positive-side line 32.

[0018] The charging and discharging circuit 40 includes a charging and discharging line 42 and a charging and discharging connector 44. The charging and discharging line 42 has a charging and discharging positive electrode side line 42p and a charging and discharging negative electrode side line 42n. The charging and discharging positive electrode side line 42p is connected to the first positive electrode side line 31 and the charging and discharging connector 44. The charging and discharging negative electrode side line 42n is connected to the negative electrode side line 33 and the charging and discharging connector 44. The charging and discharging connector 44 is configured to be connectable to the stand connector 82 of the charging and discharging stand 80.

[0019] The system ECU 50 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, a communication port, various drive circuits, and various logic ICs. Signals from various sensors are input to the system ECU 50. Examples of the various sensors include voltage sensors 13v, 14v that detect the voltages Vb1, Vb2 of the first and second batteries 13, 14, temperature sensors 13t, 14t that detect the temperatures Tb1, Tb2 of the first and second batteries 13, 14, a rotational position sensor 20a that detects the rotational position of the rotor of the motor 20, current sensors 20u, 20v, 20w that detect the currents Iu, Iv, Iw flowing through each phase (U phase, V phase, W phase) of the motor 20, voltage sensors 26v, 28v that detect the voltages VH, VL of the first and second capacitors 26, 28, and current sensors 31i, 32i that detect the currents Ip1, Ip2 of the first and second positive electrode side lines 31, 32. When the series relay Rs is in the off state and the first and second parallel relays Rp1, Rp2 are in the on state, that is, when the first battery 13 is connected to the first positive electrode side line 31 and the negative electrode side line 33 and the second battery 14 is connected to the second positive electrode side line 32 and the negative electrode side line 33, the current Ip1 of the first positive electrode side line 31 is equal to the current of the first battery 13, and the current Ip2 of the second positive electrode side line 32 is equal to the current of the second battery 14. Also, when the series relay Rs is in the on state and the first and second parallel relays Rp1, Rp2 are in the off state, that is, when the first and second batteries 13, 14 are connected in series, the current Ip1 flowing through the first positive electrode side line 31 is equal to the currents of the first and second batteries 13, 14.

[0020] The system ECU 50 calculates the state of charge (SOC) SOC1 and SOC2 of the first and second batteries 13 and 14. The state of charge SOC1 and SOC2 are calculated based on, for example, the integrated values of the currents Ip1 and Ip2 (the currents of the first and second batteries 13 and 14) of the first and second positive electrode lines 31 and 32 when the series relay Rs is in the off state and the first and second parallel relays Rp1 and Rp2 are in the on state, or the integrated value of the current Ip1 (the current of the first and second batteries 13 and 14) of the first positive electrode line 31 when the series relay Rs is in the on state and the first and second parallel relays Rp1 and Rp2 are in the off state.

[0021] The system ECU 50 outputs control signals to the first and second inverters 22 and 24 and control signals to each relay. Examples of each relay include the series relay Rs, the first and second parallel relays Rp1 and Rp2. The system ECU 50 is capable of communicating with the stand electronic control unit (hereinafter referred to as the "stand ECU") 86 of the charging / discharging stand 80.

[0022] The charging and supplying stand 80 comprises a stand connector 82, a power converter 84, and a stand ECU 86. The stand connector 82 is configured to be connectable to the charging and supplying connector 44 of the power supply system 10. The power converter 84 is connected to a power grid and is configured to convert AC power from the power grid into DC power with voltage and current adjustments and supply it to the stand connector 82, or to convert DC power from the stand connector 82 into AC power with voltage and current adjustments and supply it to the power grid. The stand ECU 86, like the system ECU 50, is equipped with a microcomputer. Signals from various sensors are input to the stand ECU 86. Control signals are output from the stand ECU 86 to the power converter 84. As described above, the stand ECU 86 is capable of communicating with the system ECU 50 of the power supply system 10. Examples of the charging and power supply stand 80 include a first voltage stand where the voltage of the power exchanged with the power supply system 10 is a first voltage Vs1 (e.g., 400V), a second voltage stand where this voltage is a second voltage Vs2 (e.g., 800V) which is higher than the first voltage Vs1, and a third voltage stand in which the voltage can be selectively set to one of the first, second, or second voltages Vs1 or Vs2.

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

[0024] In parallel charging and power supply, the series relay Rs is turned off and the first and second parallel relays Rp1 and Rp2 are turned on, thereby connecting the first and second batteries 13 and 14 in parallel as seen from the charging and power supply connector 44, and power is exchanged between the charging and power supply stand 80 and the first and second batteries 13 and 14. Figure 2 is an explanatory diagram showing the current flow during parallel charging in parallel charging and power supply. In the figure, the thick solid line with an arrow indicates the charging current of the first battery 13, and the thick dashed line with an arrow indicates the charging current of the second battery 14. Note that in Figure 2, only the V phase of the current for the motor 20 and the first and second inverters 22 and 24 is shown, but the U and W phases are similar. In parallel charging, the first battery 13 is charged by current flowing from the charging connector 44 in the following order, as shown by the thick solid line with arrow in Figure 2: charging positive side line 42p, first positive side line 31, first battery 13, parallel line 36 (first parallel relay Rp1), negative side line 33, charging negative side line 42n, and charging connector 44. The second battery 14 is charged by current flowing from the charging connector 44 in the following order, as shown by the thick dashed line with arrow in Figure 2: charging positive side line 42p, first positive side line 31, first inverter 22, motor 20, second inverter 24, second positive side line 32 (second parallel relay Rp2), second battery 14, negative side line 33, charging negative side line 42n, and charging connector 44. In parallel power supply, the direction of the current is reversed compared to parallel charging.

[0025] In series charging, the first and second batteries 13 and 14 are connected in series by turning on the series relay Rs and turning off the first and second parallel relays Rp1 and Rp2, and power is exchanged between the charging stand 80 and the first and second batteries 13 and 14. In series charging, the first and second batteries 13 and 14 are charged by current flowing in the following order from the charging connector 44: positive charging line 42p, first positive line 31, first battery 13, series line 35 (series relay Rs), second battery 14, negative line 33, negative charging line 42n, and charging connector 44. In series charging, the direction of the current is reversed compared to series charging.

[0026] Next, the operation of the power supply system 10 of the embodiment, in particular, the operation during parallel charging will be described. Note that parallel power supply can be considered in the same way. During parallel charging, the system ECU 50 basically controls transistors T11~T16 and T21~T26 by setting the first and second duty commands Du1*, Du2*, Dv1*, Dv2* for the U-phase, V-phase, and W-phase for the first and second inverters 22 and 24. Hereinafter, this control will be referred to as "duty control". The first duty command Du1* for the U-phase is the ratio of the on-time of transistor T11 to the sum of the on-time of transistor T11 and transistor T14 of the first inverter 22. The same applies to the second duty command Du2* for the U-phase, the first and second duty commands Dv1*, Dv2* for the V-phase, and the first and second duty commands Dw1*, Dw2* for the W-phase.

[0027] Here, we will explain how to set the first and second duty commands Du1* and Du2* for the U phase. The method for setting the first and second duty commands Dv1*, Dv2*, Dw1*, and Dw2* for the V and W phases is the same. When setting the first and second duty commands Du1* and Du2* for the U phase, first, the first and second feedforward terms Duff1 and Duff2 in the feedback control are calculated. The first and second feedforward terms Duff1 and Duff2 are calculated, for example, using the voltages VH and VL of the first and second capacitors 26 and 28 as values ​​(VL / VH) and (VH / VL), respectively. Note that the first and second feedforward terms Duff1 and Duff2 may also be calculated taking into account the U phase current command Iu* described later.

[0028] Next, the feedback term Dufb in the feedback control is calculated. The feedback term Dufb is calculated by equation (1), for example, using the phase current command Iu*, the average phase current Iuav which is the average value of the phase current Iu over a predetermined time, and the gains Kp and Ki of the proportional and integral terms. The phase current command Iu* is calculated as, for example, 1 / 3 of the current command Ip2* (the target value of the average current Ip2av which is the average value of the current Ip2 of the second positive electrode line 32 over a predetermined time), which is obtained as the product of the required power Ps* to be supplied from the charging stand 80 to the power supply system 10 and the required distribution ratio Rd* of the charging power of the first and second batteries 13 and 14. The required power Ps* is calculated as, for example, the sum of the required powers Pb1* and Pb2* of the first and second batteries 13 and 14 based on the storage ratios SOC1 and SOC2 of the first and second batteries 13 and 14. The required allocation ratio Rd* is the ratio of the required power Pb2* to the sum of the required power Pb1* and Pb2*, and is set, for example, based on the relative magnitudes of the storage ratios SOC1 and SOC2 of the first and second batteries 13 and 14.

[0029] Dufb=Kp·(Iu*-Iuav)+Ki·∫(Iu*-Iuav)dt (1)

[0030] Next, the first and second duty cycle commands Du1* and Du2* are calculated. The first duty cycle command Du1* is set to a value of 1 as an upper limit guard, which is the sum of the first feedforward term Duff1 and the feedback term Dufb. The second duty cycle command Du2* is set to a value of 1 as an upper limit guard, which is the sum of the second feedforward term Duff2 and the feedback term Dufb. When the first duty cycle command Du1* is less than 1, transistors T11 and T14 are switched using the first duty cycle command Du1*. When the first duty cycle command Du1* is 1, transistor T11 is fixed on and transistor T14 is fixed off. The control of transistors T21 and T24 based on the second duty cycle command Du2* is done similarly.

[0031] With this control, when the second upper arm (transistors T21-T23) of the 3 phases of the second inverter 24 is fixed ON, the second lower arm (transistors T24-T26) of the 3 phases is fixed OFF, and the first upper arm and first lower arm (transistors T11-T16) of the 3 phases of the first inverter 22 are switched, the motor 20 and the first inverter 22 function as a 3-phase step-down converter. Also, when the first upper arm (transistors T11-T13) of the 3 phases of the first inverter 22 is fixed ON, the first lower arm (transistors T14-T16) of the 3 phases is fixed OFF, and the second upper arm and second lower arm (transistors T21-T26) of the 3 phases of the second inverter 24 are switched, the motor 20 and the second inverter 24 function as a 3-phase step-up converter.

[0032] Furthermore, in the power supply system 10 of this embodiment, during parallel charging, the system ECU 50 repeatedly executes the processing routine shown in Figure 3. When this routine is executed, the system ECU 50 first determines whether it is in ON-fixed control mode or the duty cycle control mode described above (step S100). Here, ON-fixed control is a control that turns on all of the first and second upper arms (transistors T111~T13, T21~T23) of the three phases of the first and second inverters 22 and 24, and turns off all of the first and second lower arms (transistors T14~T16, T24~26) of the three phases.

[0033] When it is determined in step S100 that duty cycle control is in operation, it is determined whether the difference ΔIu (the absolute value of the value obtained by subtracting the average phase current Iuav from the phase current command Iu*) of the U-phase is less than the threshold ΔIref1 (step S110), and whether the first and second duty cycle commands Du1* and Du2* of the U-phase are both greater than or equal to the threshold Dref (step S120). Here, the threshold ΔIref1 is used to determine whether the difference ΔIv is relatively small (the difference ΔIp between the current command Ip2* and the current Ip2av of the second positive electrode line 32 is relatively small). The threshold Dref is used to determine whether the first and second duty cycle commands Du1* and Du2* are both around a value of 1. When the phase current command Iu* and the phase current Iu are significantly different, or when one of the first or second duty cycle commands Du1* or Du2* is small, switching to ON-fixed control may cause the current Ip2 (current of the second battery 14) of the second positive electrode line 32 to become unstable. The processes in steps S110 and S120 are for determining whether or not this possibility exists.

[0034] If, in step S110, it is determined that the difference ΔIu between the U-phase phase current command Iu* and the average phase current Iuav is greater than or equal to the threshold ΔIref1, or if, in step S120, it is determined that either the first or second duty cycle command Du1* or Du2* of the U-phase is less than the threshold Dref, this routine is terminated. In this case, duty cycle control is continued.

[0035] If, in step S110, it is determined that the difference ΔIu between the U-phase phase current command Iu* and the average phase current Iuav is less than the threshold ΔIref1, and in step S120, it is determined that both the first and second duty commands Du1* and Du2* of the U-phase are greater than or equal to the threshold Dref, then the routine is terminated by transitioning from duty control to on-fixed control (step S130). By transitioning to on-fixed control when the difference ΔIv is less than the threshold ΔIref and both the first and second duty commands Du1* and Du2* of the U-phase are greater than or equal to the threshold Dref, it is possible to suppress disturbances in the current Ip2 of the second positive electrode line 32 (current of the second battery 14) that occur when transitioning from duty control to on-fixed control (start of on-fixed control). In addition, by executing on-fixed control, switching losses of transistors T11~T16 and T21~T26 of the first and second inverters 22 and 24 can be suppressed.

[0036] If it is determined in step S100 that the system is in ON fixed control mode, it is determined whether the difference ΔIu between the U-phase current command Iu* and the average phase current Iuav is greater than or equal to the threshold ΔIref2, which is greater than or equal to the threshold ΔIref1 (step S140). If it is determined that the difference ΔIu is less than the threshold ΔIref2, this routine is terminated. In this case, the ON fixed control is continued.

[0037] In step S140, when it is determined that the difference ΔIu between the U-phase phase current command Iu* and the average phase current Iuav is greater than or equal to the threshold ΔIref2, the integral term in the feedback control of the duty cycle control (see the second term on the right-hand side of equation (1) above) is reset to 0 (step S150), the system transitions from ON fixed control to duty cycle control (step S160), and the routine terminates. This allows the phase current Iu to follow the phase current command Iu* when the difference ΔIu becomes greater than or equal to the threshold ΔIref2 due to changes in the phase current command Iu*. Furthermore, by resetting the integral term in the feedback control of the duty cycle control to 0 when transitioning from ON fixed control to duty cycle control, disturbances in the first and second duty cycle commands Du1*, Du2* of the U-phase can be suppressed, and disturbances in the current Ip2 of the second positive electrode line 32 (current of the second battery 14) can be suppressed.

[0038] In the power supply system 10 of the embodiment described above, during parallel charging or parallel power supply, when the difference ΔIv is less than the threshold ΔIref during duty cycle control and both the first and second duty cycle commands Du1* and Du2* of the U phase are greater than or equal to the threshold Dref, the system switches to ON-fixed control. This makes it possible to suppress disturbances in the current Ip2 of the second positive electrode line 32 (current of the second battery 14) that occur when transitioning from duty cycle control to ON-fixed control (start of ON-fixed control).

[0039] In the embodiment described above, step S110 of the processing routine in Figure 3 determines whether the difference ΔIu between the U-phase phase current command Iu* and the average phase current Iuav is less than the threshold ΔIref. However, the embodiment is not limited to this. For example, instead of the difference ΔIu, the difference ΔIv between the V-phase phase current command Iv* and the average phase current Ivav (the average value of the phase current Iv over a predetermined time) may be used, or the difference ΔIw between the W-phase phase current command Iw* and the average phase current Iwav (the average value of the phase current Iw over a predetermined time) may be used, or the maximum value of the differences ΔIu, ΔIv, and ΔIw may be used. The phase current commands Iv* and Iw* are calculated in the same way as the phase current command Iu*. Alternatively, instead of the processing in step S100, it may be determined whether the difference between the current command Ip2* and the average current Ip2av is less than the threshold ΔIp2ref. The threshold ΔIp2ref is, for example, about three times the threshold ΔIref. The process in step S140 can be considered in the same way.

[0040] In the embodiment described above, the process in step S120 of the processing routine in Figure 3 is to determine whether the first and second duty commands Du1* and Du2* of the U phase are both greater than or equal to the threshold Dref, but the embodiment is not limited to this. For example, instead of the first and second duty commands Du1* and Du2* of the U phase, the first and second duty commands Dv1* and Dv2* of the V phase may be used, or the first and second duty commands Dw1* and Dw2* of the W phase may be used, or the minimum value among the first and second duty commands Du1*, Du2*, Dv1*, Dv2*, Dw1*, and Dw2* of the U, V, and W phases may be used.

[0041] In the embodiment described above, the integral term in the feedback control of the duty cycle is reset to 0 when transitioning from fixed ON control to duty cycle control, but this is not required.

[0042] In the embodiments described above, we explained the process of parallel charging and parallel power supply, that is, the exchange of power between the first and second batteries 13 and 14 and an external device (charging and power supply stand 80) via the charging and power supply connector 44. In addition, the process of exchanging power between the first and second batteries 13 and 14 via the first inverter 22, motor 20, and second inverter 24 can be considered in a similar manner.

[0043] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on the main elements of the embodiment and the means for solving the problem will be explained. In the embodiment, the first and second batteries 13 and 14 correspond to "first and second batteries", the motor 20 corresponds to "motor", the first inverter 22 corresponds to "first inverter", the second inverter 24 corresponds to "second inverter", the charging and power supply connector 44 corresponds to "connector", and the system ECU 50 corresponds to "control device".

[0044] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0045] The above describes the forms for implementing this disclosure using embodiments, but this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0046] This disclosure can be used in industries such as the manufacturing of power supply systems. [Explanation of Symbols]

[0047] 10 Power supply system, 12 Battery, 13 First battery, 13t, 14t Temperature sensor, 13v, 14v, 26v, 28v Voltage 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 side line, 32 Second positive side line, 33 Negative side line, 35 Series line, 36 Parallel line, 40 Charging and power supply circuit, 42 Charging and power supply line, 42n Charging and power supply negative side line, 42p Charging and power supply positive side line, 44 Charging and power supply connector, 50 System ECU, 80 Charging and power supply stand, 82 Stand connector, 84 Power converter, 86 Stand ECU, D11~D16, D21~D26 diodes, T11~T16, T21~T26 transistors.

Claims

1. The first and second batteries, A motor having a three-phase open winding, A first inverter is connected to the first battery via a first positive electrode line and a first negative electrode line, and is connected to one end of the three-phase open winding, and has a three-phase first upper arm and a first lower arm. A second inverter is connected to the second battery via a second positive electrode line and a second negative electrode line, and is connected to the other end of the three-phase open winding, and has a three-phase second upper arm and a second lower arm. A connector connected to the first positive electrode line and the negative electrode line, A control device for controlling the first and second inverters, A power supply system comprising, When the control device exchanges power between the first and second batteries and the outside via the connector, it sets the first and second duty cycle commands by current command and feedback control based on the current, and performs duty cycle control to control the first and second inverters. During the duty cycle control, when the difference between the current command and the current is less than a first predetermined difference and the first and second duty cycle commands are greater than or equal to a predetermined value, it transitions to on-fix control, which turns the three-phase first and second upper arms on. Power supply system.

2. A power supply system according to claim 1, The control device transitions to duty cycle control when the difference reaches a second predetermined difference or greater than the first predetermined difference during the ON fixed control. Power supply system.

3. A power supply system according to claim 2, The control device resets the integral term in the feedback control to 0 when transitioning from the ON fixed control to the duty cycle control. Power supply system.

4. A power supply system according to any one of claims 1 to 3, The control device also performs the duty cycle control when exchanging power between the first and second batteries via the first inverter, the motor, and the second motor, and when the difference is less than the first predetermined difference and the first and second duty cycle commands are greater than or equal to the predetermined values ​​during the duty cycle control, it transitions to the ON fixed control. Power supply system.

Images