Charging system

Abstract

To provide a charging system capable of supplying power supplied from a charging facility to an auxiliary machine with high efficiency.SOLUTION: A charging system 1 includes: a DC voltage conversion unit that converts a DC voltage on a charging facility side into a secondary voltage different from a battery voltage and supplies the secondary voltage to an auxiliary device 4; and a control unit 10 that controls the DC voltage conversion unit. The DC voltage conversion unit includes coils 32U, 32V, and 32W of a plurality of phases, and switches TH1 to TH3 and TL1 to TL3 provided for the respective phases of the plurality of phases. The control unit 10 determines a secondary voltage from operation request information of the auxiliary machine 4, determines the number of phases of the coils 32U, 32V, and 32W to be driven based on the secondary voltage, drives the determined number of phases, and supplies power to the auxiliary machine 4.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a charging system. [Background technology]

[0002] In recent years, research and development has been conducted into charging mobility vehicles equipped with secondary batteries that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable, and advanced energy.

[0003] Regarding charging and power supply for mobility vehicles equipped with secondary batteries, there are two types of charging equipment, such as charging stations: 400V class with an upper voltage limit of 500V, and 800V class with an upper voltage limit of 1000V. If a mobility vehicle is only compatible with 400V class charging equipment, it will not be able to take advantage of the rapid charging capabilities of 800V class charging equipment.

[0004] When a mobility device is compatible with 400V and 800V charging facilities, it is generally charged by boosting the voltage to 800V using a voltage converter when charging with 400V charging facilities, or by lowering the voltage to 400V when charging with 800V charging facilities. However, charging efficiency deteriorates when the voltage converter is used for charging.

[0005] In contrast, there is also known a mobility that can be charged at both 400V-class charging equipment and 800V-class charging equipment without using a voltage converter for charging by switching the connection method of the battery module (for example, Patent Document 1).

[0006] In addition, the accessories used in the mobility must also be driven by the power supplied from the charging facility during charging. For this reason, it has been proposed to provide a DC-DC converter in the mobility, convert the power supplied from the charging facility with the DC-DC converter, and supply the converted power to the accessories (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US Patent Application Publication No. 2023 / 0299695 [Patent Document 2] US Patent Application Publication No. 2023 / 0150378 Summary of the Invention [Problem to be solved by the invention]

[0008] When converting power supplied from a charging facility using a DC-DC converter, it is desirable to efficiently convert the voltage before supplying it to auxiliary equipment.

[0009] The present invention provides a charging system that can supply power supplied from a charging facility to an auxiliary device with high efficiency. [Means for solving the problem]

[0010] The charging system of the present invention comprises: A battery, an auxiliary device that is driven by power supplied from the battery when the battery is discharging, and to which the supply of power from the battery is cut off when the battery is charging; a DC voltage conversion unit that converts a DC voltage on the charging equipment side into an auxiliary side voltage different from a battery voltage and supplies the auxiliary side voltage to the auxiliary; a control unit that controls the DC voltage conversion unit, the DC voltage converter includes a plurality of phase coils and a converter provided for each of the plurality of phases, the control unit has a phase number selection unit that selects the number of phases to be driven from the plurality of phases, The number-of-phases selection unit determining the auxiliary side voltage from the operation request information of the auxiliary; determining the number of phases to be driven based on the auxiliary side voltage; The determined number of phases are driven to supply power to the auxiliary equipment. [Effects of the Invention]

[0011] According to the present invention, power supplied from a charging facility can be supplied to an auxiliary device with high efficiency. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing a configuration of a charging system 1 of a first embodiment. [Figure 2] FIG. 10 is a diagram showing a first voltage state of the battery 2 (started at 800 V). [Figure 3] FIG. 10 is a diagram showing a second voltage state of the battery 2 (started at 400 V). [Figure 4] 2 is a diagram showing a current flow when an electric vehicle equipped with the charging system 1 of the first embodiment is running. FIG. [Figure 5] 3 is a diagram showing a current flow during charging at a first voltage (800 V) of an electric vehicle equipped with the charging system 1 of the first embodiment. FIG. [Figure 6] 4 is a diagram showing a current flow during charging at a second voltage (400 V) of an electric vehicle equipped with the charging system 1 of the first embodiment. FIG. [Figure 7] 1 is a schematic diagram showing a schematic configuration of a charging system 1 of a first embodiment. [Figure 8] 4 is a diagram showing a current flow during two-phase boost charging at a second voltage (400 V) in the charging system 1 of the first embodiment. FIG. [Figure 9] 4 is a diagram showing a current flow during one-phase boosting during charging at a second voltage (400 V) in the charging system 1 of the first embodiment. FIG. [Figure 10] 3 is a flowchart showing a boost control method 1 of the first embodiment. [Figure 11] 10 is a diagram illustrating a method for determining a secondary voltage in the boost control method 1. FIG. [Figure 12] FIG. 10 is a diagram illustrating a method for determining a boost phase in the boost control method 1. [Figure 13] 4 is a flowchart showing a second boost control method according to the first embodiment. [Figure 14] 10 is a diagram showing a method for determining a secondary voltage in the boost control method 2. FIG. [Figure 15] 4 is a flowchart showing a boost control method 3 of the first embodiment. [Figure 16] 10 is a diagram illustrating a method for determining a secondary voltage and a boost phase in boost control method 3. FIG. [Figure 17] FIG. 4 is a schematic diagram showing a schematic configuration of a charging system 1 according to a second embodiment. [Figure 18] FIG. 10 is a diagram showing a current flow during three-phase boosting during charging at a second voltage (400 V) in the charging system 1 of the second embodiment. [Figure 19] FIG. 10 is a diagram showing a current flow during two-phase boost charging at a second voltage (400 V) in the charging system 1 of the second embodiment. [Figure 20] FIG. 10 is a diagram showing a current flow during one-phase boosting during charging at a second voltage (400 V) in the charging system 1 of the second embodiment. [Figure 21] FIG. 10 is a diagram illustrating a method for determining a boost phase in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS.

[0014] [First embodiment] A charging system 1 according to the first embodiment shown in Fig. 1 is mounted on an electric vehicle such as an electric car. An electric vehicle equipped with the charging system 1 is compatible with 400V-class and 800V-class charging facilities, and is capable of not only rapidly charging a battery 2 at a charging voltage of 400V or 800V, but also driving a three-phase motor 3 and accessories 4 at a base voltage of 800V. Note that the accessories 4 can be driven at a voltage other than 800V.

[0015] Specifically, as shown in FIG. 1, the charging system 1 includes a battery 2, a three-phase motor 3, an auxiliary device 4, an inverter 5 (PDU), power supply circuits 11P, 11N, auxiliary device drive circuits 12P, 12N, DC power supply circuits 13P, 13N, a branch circuit 14, and a control unit 10.

[0016] As shown in Figures 1 to 3, battery 2 includes first power storage unit 21, second power storage unit 22, first to fifth contactors M / C, S / C_A, S / C_B, S / C_C, P / C, first resistor R1, current sensor IS, and current breaker FUSE.

[0017] First power storage unit 21 and second power storage unit 22 are each a battery module capable of charging and discharging 400V.

[0018] The first contactor M / C is disposed at the end of the positive electrode side of the battery 2, and functions as a main switch that turns on / off the connection of the battery 2 with the outside (power supply circuit 11P).

[0019] The second to fourth contactors S / C_A, S / C_B, and S / C_C switch the connection state between the first power storage unit 21 and the second power storage unit 22. For example, as shown in FIG. 2, when the second contactor S / C_A is turned ON and the third contactor S / C_B and the fourth contactor S / C_C are turned OFF, the battery 2 enters a first voltage state (800 V start) in which the first power storage unit 21 and the second power storage unit 22 are connected in series, and charging and discharging at 800 V becomes possible. Also, as shown in FIG. 3, when the second contactor S / C_A is turned OFF and the third contactor S / C_B and the fourth contactor S / C_C are turned ON, the battery 2 enters a second voltage state (400 V start) in which the first power storage unit 21 and the second power storage unit 22 are connected in parallel, and charging and discharging at 400 V becomes possible. The term "start" is a concept that includes driving the electric vehicle equipped with the charging system 1 while the vehicle is traveling, and charging the electric vehicle while the vehicle is stopped.

[0020] The fifth contactor P / C and the first resistor R1 are arranged in series and in parallel with the first contactor M / C. In the first voltage state and the second voltage state, the fifth contactor P / C is turned on before the first contactor M / C is turned on, thereby protecting the first contactor M / C from excessive inrush current.

[0021] Current sensor IS is arranged between first contactor M / C and power storage units 21 and 22 to measure the current.

[0022] The current breaker FUSE is disposed at the end of the negative electrode side of the battery 2, and cuts off the connection of the battery 2 to the outside (power supply circuit 11N) in the event of an abnormality. In the charging system 1 of this embodiment, the current breaker FUSE is configured with a pyro-fuse that can intentionally cut off current in response to an electrical signal, and in the event of an abnormality (such as a vehicle collision or a short circuit in the battery 2), the current breaker FUSE is cut off and all contactors in the battery 2 are turned OFF (open).

[0023] Three-phase motor 3 includes three-phase coils 32U, 32V, and 32W, one end of which is connected at neutral point 31, and is rotationally driven by power supplied from battery 2 via inverter 5. Three-phase motor 3 of this embodiment includes U-phase terminal 33U, V-phase terminal 33V, and W-phase terminal 33W, which are connected to the other ends of coils 32U, 32V, and 32W. U-phase terminal 33U, V-phase terminal 33V, and W-phase terminal 33W are connected to inverter 5. The other end of any one of coils 32U, 32V, and 32W is connected to branch circuit 14 at connection 34. In this embodiment, of three-phase coils 32U, 32V, and 32W, coil 32U is connected to branch circuit 14 at connection 34 located between U-phase terminal 33U and inverter 5.

[0024] The inverter 5 converts the DC power supplied from the battery 2 into three-phase AC power by switching a plurality of switching elements, thereby rotating and driving the three-phase motor 3. Furthermore, as will be described in detail later, when a DC current (400 V) is supplied from the branch circuit 14 to the connection part 34, the inverter 5 can function as a boost circuit (DC voltage converter) that boosts the DC current by switching a plurality of switching elements using the coil connected to the branch circuit 14 and one or two other phase coils.

[0025] The accessories 4 are in-vehicle devices that can be driven by DC power from the battery 2 and an external power source, and include, for example, an electric compressor E-COMP for an air conditioner (A / C), an electric heater ECH, and an accessory converter DCDC. The electric compressor E-COMP and the electric heater ECH are high-voltage in-vehicle devices, and the accessory converter DCDC reduces the DC power from the battery 2 and the external power source to drive the low-voltage in-vehicle devices. The accessories 4 are connected to the battery 2 via accessory drive circuits 12P and 12N, a sixth contactor VS / C, and power supply circuits 11P and 11N. In this embodiment, the accessories 4 operate at a base voltage of 800 V while the vehicle is running. However, the accessories 4 can operate at voltages other than 800 V, and are configured to operate at a more efficient drive voltage when charging at 400 V, as described below.

[0026] The power supply circuits 11P, 11N are configured as a pair of positive and negative circuits and connect the battery 2 and the inverter 5 (three-phase motor 3). The power supply circuits 11P, 11N are provided with connection parts 111P, 111N with the DC power supply circuits 13P, 13N, and connection parts 112P, 112N with the auxiliary drive circuits 12P, 12N (auxiliary 4) are provided on the inverter 5 side of the connection parts 111P, 111N. In addition, the positive side power supply circuit 11P is provided with a sixth contactor VS / C that turns the circuit ON / OFF between the connection part 112P with the auxiliary drive circuit 12P and the connection part 111P with the DC power supply circuit 13P. In addition, a first voltage sensor V_PIN, a first smoothing capacitor C1, and a second resistor R2 are provided on the inverter 5 side of the power supply circuits 11P, 11N. The first voltage sensor V_PIN, the first smoothing capacitor C1, and the second resistor R2 are provided on a circuit connecting the positive power supply circuit 11P and the negative power supply circuit 11N. The second resistor R2 is provided to discharge the first smoothing capacitor C1 when the circuit is interrupted.

[0027] The DC power supply circuits 13P, 13N are configured as a pair of positive and negative terminals, with one end provided with charging terminals 131P, 131N to which an external power source such as a charging facility can be connected, and the other end connected to the power supply circuits 11P, 11N via connectors 111P, 111N. The DC power supply circuits 13P, 13N are provided with seventh contactors QC / C_A and eighth contactors QC / C_B that turn the respective circuits ON / OFF. A second voltage sensor V_BAT is provided at a position closer to the connectors 111P, 111N than the seventh contactors QC / C_A and eighth contactors QC / C_B. A third voltage sensor V_QC is provided at a position closer to the charging terminals 131P, 131N than the seventh contactors QC / C_A and eighth contactors QC / C_B.

[0028] Branch circuit 14 branches off from positive-side DC power supply circuit 13P at a position closer to connection 111P than the eighth contactor QC / C_A and the second voltage sensor V_BAT, and is connected to one of the coils of three-phase motor 3 via connection 34. A ninth contactor QC / C_C that turns the circuit on and off is provided in the middle of branch circuit 14.

[0029] The control unit 10 is, for example, a vehicle ECU, and controls the driving and charging of the charging system 1. More specifically, the control unit 10 controls the ON / OFF of each of the contactors M / C, S / C_A, S / C_B, S / C_C, P / C, VS / C, QC / C_A, QC / C_B, and QC / C_C, detects welding of these contactors, controls the inverter 5, and so on.

[0030] Next, the operation of the charging system 1 will be described with reference to FIGS.

[0031] FIG. 4 is a diagram showing the flow of current when the electric vehicle equipped with the charging system 1 of the first embodiment is running (driven at 800V).

[0032] As described above, the electric vehicle equipped with the charging system 1 drives the three-phase motor 3 and the accessories 4 with a base voltage of 800V, and when traveling, the battery 2 is controlled to the 800V start state shown in Fig. 2. In addition, the control unit 10 turns on the first contactor M / C and the sixth contactor VS / C, and turns off the seventh contactor QC / C_A, the eighth contactor QC / C_B, and the ninth contactor QC / C_C.

[0033] In this mode, a voltage of 800V is supplied from the battery 2 to the three-phase motor 3 via the inverter 5, enabling the electric vehicle to run. At this time, the accessories 4 are driven by a voltage of 800V supplied from the battery 2 via the power supply circuits 11P, 11N and the accessory drive circuits 12P, 12N.

[0034] FIG. 5 is a diagram showing the current flow during second voltage charging (800 V charging) of the electric vehicle equipped with the charging system 1 of the first embodiment.

[0035] When charging with an 800V-class charging facility, the battery 2 is controlled to the 800V start-up state shown in Fig. 2. The control unit 10 also turns on the first contactor M / C, the seventh contactor QC / C_A, the eighth contactor QC / C_B, and the sixth contactor VS / C, and turns off the ninth contactor QC / C_C. As a result, a voltage of 800V is supplied to the battery 2 from the charging terminals 131P and 131N, and also to the auxiliary equipment 4 via the power supply circuit 11P and the auxiliary equipment drive circuit 12P.

[0036] FIG. 6 is a diagram showing the current flow during second voltage charging (400V charging) of the electric vehicle equipped with the charging system 1 of the first embodiment.

[0037] When charging with a 400V-class charging facility, the battery 2 is controlled to the 400V start-up state shown in Fig. 3. The control unit 10 also turns on the first contactor M / C, the seventh contactor QC / C_A, the eighth contactor QC / C_B, and the ninth contactor QC / C_C, and turns off the sixth contactor VS / C. As a result, a voltage of 400V is supplied to the battery 2 from the charging terminals 131P and 131N, and a voltage of 400V is supplied to the coil 32U via the branch circuit 14. Furthermore, turning off the sixth contactor VS / C cuts off the power supply from the battery 2 to the auxiliary equipment 4.

[0038] Here, in order to drive the auxiliary device 4 whose base voltage is 800V, it is necessary to boost the voltage of 400V to an auxiliary device driving voltage, which is the driving voltage for the auxiliary device 4. The auxiliary device driving voltage may or may not be 800V.

[0039] Next, the configuration of the inverter 5 and the voltage step-up operation performed by the three-phase motor 3 and the inverter 5 will be described with reference to FIGS.

[0040] FIG. 7 is a schematic diagram showing a schematic configuration of the charging system 1 of the first embodiment. 7 , the inverter 5 includes a first tributary circuit 51 including a first high-side switch TH1, a first low-side switch TL1, and a first node P1 connecting the first high-side switch TH1 and the first low-side switch TL1 in series, a second tributary circuit 52 including a second high-side switch TH2, a second low-side switch TL2, and a second node P2 connecting the second high-side switch TH2 and the second low-side switch TL2 in series, and a third tributary circuit 53 including a third high-side switch TH3, a third low-side switch TL3, and a third node P3 connecting the third high-side switch TH3 and the third low-side switch TL3 in series. The high-side switch sides of the first tributary circuit 51, the second tributary circuit 52, and the third tributary circuit 53 are connected in parallel to the positive power supply circuit 11P and the low-side switch sides of the first tributary circuit 51, the second tributary circuit 52, and the third tributary circuit 53 are connected in parallel to the positive power supply circuit 11P and the negative power supply circuit 11N.

[0041] The first node P1 is connected to the U-phase terminal 33U and is therefore connected to the coil 32U, the second node P2 is connected to the V-phase terminal 33V and is therefore connected to the coil 32V, and the third node P3 is connected to the W-phase terminal 33W and is therefore connected to the coil 32W. The switches TH1, TL1, TH2, TL2, TH3, and TL3 are configured, for example, with MOSFETs, and are opened and closed by the control unit 10 adjusting the gate voltage.

[0042] A diode that functions as a freewheeling diode is connected in parallel to each of the switches TH1, TL1, TH2, TL2, TH3, and TL3. The freewheeling diodes are provided to prevent damage to the switching elements by returning (regenerating) the current that flows back from the motor 3 side to the battery 2 side when the switches TH1, TL1, TH2, TL2, TH3, and TL3 are turned off. That is, the inverter 5 allows current to flow from the three-phase motor 3 side to the battery 2 side regardless of whether the gate is on or off, and allows current to flow from the battery 2 side to the three-phase motor 3 side only when the gate is on.

[0043] When charging with a 400V-class charging facility, the control unit 10 controls the charging system 1 to the state shown in FIG. 6 described above. As a result, a voltage of 400V is supplied to the battery 2 from the charging terminals 131P and 131N, and a voltage of 400V is supplied to the coil 32U via the branch circuit 14. Furthermore, because the power supply from the battery 2 to the auxiliary equipment 4 is cut off, the voltage of 400V must be boosted to an auxiliary equipment drive voltage for the auxiliary equipment 4 in order to drive the auxiliary equipment 4. In the following description, the boosted voltage corresponding to the auxiliary equipment drive voltage may be referred to as a secondary voltage.

[0044] FIG. 8 is a diagram showing the current flow during two-phase boosting during charging at the second voltage (400 V) in the charging system 1 of the first embodiment. 6, the control unit 10 performs a boost operation by switching the second low-side switch TL2 and the third low-side switch TL3 between an ON state and an OFF state of the second low-side switch TL2 and the third low-side switch TL3. Note that the other switches TL1 and TH1 to TH3 of the inverter 5 are maintained in the OFF state.

[0045] As a result, the energy stored in coils 32U, 32V, and 32W when the second low-side switch TL2 and the third low-side switch TL3 are in the ON state is released when the second low-side switch TL2 and the third low-side switch TL3 are in the OFF state, and the 400V voltage supplied from the charging terminals 131P and 131N is boosted to a secondary voltage and supplied from the inverter 5 to the auxiliary device 4. Hereinafter, this boost operation state by the three-phase motor 3 and the inverter 5 is referred to as two-phase boost mode.

[0046] FIG. 9 is a diagram showing the current flow during one-phase boosting during charging at the second voltage (400 V) in the charging system 1 of the first embodiment. 6, the control unit 10 performs a boost operation by switching the third low-side switch TL3 between an ON state and an OFF state of the third low-side switch TL3 by high-frequency switching. Note that the other switches TL1, TL2, and TH1 to TH3 of the inverter 5 are maintained in the OFF state.

[0047] As a result, the energy stored in coils 32U and 32W when the third low-side switch TL3 is in the ON state is released when the third low-side switch TL3 is in the OFF state, and the 400 V voltage supplied from the charging terminals 131P and 131N is boosted to a secondary voltage and supplied from the inverter 5 to the auxiliary device 4. Hereinafter, this boost operation state by the three-phase motor 3 and the inverter 5 is referred to as the single-phase boost mode.

[0048] When charging to the second voltage (400V), the control unit 10 boosts the power supplied to the auxiliary device 4 in the two-phase boost mode or the one-phase boost mode described above, by determining the secondary voltage based on the operation requirement information of the auxiliary device 4 and selecting the boost mode to be used for boosting based on the determined secondary voltage. That is, the control unit 10 has a secondary voltage determination unit that determines the secondary voltage and a phase number selection unit that selects the number of phases to be driven during boosting.

[0049] Next, three voltage step-up control methods 1 to 3 that can be applied during charging at the second voltage (400V) will be described with reference to FIGS.

[0050] FIG. 10 is a flowchart showing the boost control method 1 of the first embodiment, FIG. 11 is a diagram showing a method for determining the secondary voltage of the boost control method 1, and FIG. 12 is a diagram showing a method for determining the boost phase of the boost control method 1.

[0051] In the boost control method 1, the control unit 10 determines the secondary voltage so as to minimize the loss of the auxiliary device 4 with the highest output among the multiple auxiliary devices 4, and selects the boost mode that minimizes the boost loss at the determined secondary voltage. This makes it possible to supply power from the charging facility to the auxiliary device 4 with high efficiency during charging at the second voltage (400V).

[0052] Specifically, as shown in FIG. 10 , during charging at the second voltage (400 V), the control unit 10 sets the variable n to 0 (S101) and then samples the user-requested output for the auxiliary device 4 (S102). The sampling time for the user-requested output is, for example, approximately 20 msec. Since the electric vehicle of this embodiment includes the electric compressor E-COMP, the electric heater ECH, and the auxiliary device converter DCDC as the auxiliary devices 4, the control unit 10 samples the user-requested outputs of these devices. Although the outputs of the auxiliary devices 4 vary depending on the user's request, the electric compressor E-COMP has the highest maximum output, followed by the electric heater ECH and the auxiliary device converter DCDC. Therefore, when determining the secondary voltage so as to minimize the loss of the auxiliary device 4 with the highest output among the multiple auxiliary devices 4, the loss of the electric compressor E-COMP is given the highest priority.

[0053] 10, the control unit 10 samples the user's requested output for the auxiliary device 4 (S102), and then determines whether the requested output for the air conditioner (electric compressor E-COMP) exceeds a predetermined air conditioner drive threshold T0 (e.g., 5 kW) (S103). If the result of this determination is YES, the control unit 10 calculates the secondary voltage V(n) that minimizes the loss P(n) using the calculation rule shown in Fig. 11(A) (S104, S105). If the result of this determination is NO in step S103, the control unit 10 determines whether the electric heater ECH is ON (S106). If the result of this determination is YES, the control unit 10 calculates the secondary voltage V(n) that minimizes the loss P(n) using the calculation rule shown in Fig. 11(B) (S107, S105). If the determination result in step S106 is NO, the control unit 10 calculates the secondary voltage V(n) that minimizes the loss P(n) using the calculation rule shown in FIG. 11(C) (S108, S105).

[0054] 11(A) to 11(C), correlation data showing the correlation between the secondary voltage and loss corresponding to the sampled user-requested output is extracted (see the graph on the right side of FIG. 11) from an efficiency map showing the correlation between the user-requested output, secondary voltage, and loss in each auxiliary device 4 (see the graph on the left side of FIG. 11), and the secondary voltage that minimizes the loss in the extracted correlation data is calculated. For example, as shown in FIG. 11(A), if the user-requested output of the sampled air conditioner (electric compressor E-COMP) is T1kW (T1kW>5kW), 800V that minimizes the loss within the allowable boost range (for example, 500 to 800V) is set as the secondary voltage V(n).

[0055] 10, after calculating the secondary voltage V(n) (S105), the control unit 10 determines whether the variable n is equal to or greater than, for example, 3000 (cumulative calculation time 1 minute) (S109), and if the result of this determination is YES, the control unit 10 determines the secondary voltage V(n) based on the calculation result of step S105 (S110). If the result of this determination is NO in step S109, the control unit 10 determines whether n=0 or loss P(n)-P(0)<α (α is a negative threshold) is satisfied (S111), and if the result of this determination is YES, the control unit 10 determines the secondary voltage V(n) based on the calculation result of step S105 (S110), but if the result of this determination is NO, the control unit 10 increments the variable n (S112) and returns to step S102. The processing in step S109 is intended to prevent frequent switching of control, and the processing in step S111 is intended to allow a change in the secondary voltage if the loss P(n) becomes lower than the threshold value α compared to the initial loss P(0) even if a predetermined time has not elapsed.

[0056] After determining secondary voltage V(n) (S110), control unit 10 calculates losses during boosting at determined secondary voltage V(n) and selects a boost mode that minimizes losses (S113). In charging system 1 of this embodiment, coil 32U of three-phase coils 32U, 32V, and 32W is connected to branch circuit 14 at connection 34 located between U-phase terminal 33U and inverter 5. Therefore, control unit 10 selects the number of coil phases available for boosting as the maximum number of phases that can be selected, namely, the two phases (V phase and W phase) to which charging terminal 131P is not connected. Control unit 10 selects the one-phase boost mode when the number of phases to be selected is one, and selects the two-phase boost mode when the number of phases to be selected is two.

[0057] For example, as shown in Fig. 12, a boost mode is selected that provides the smallest total loss, which is the sum of the copper loss in each boost mode for the total required output of the auxiliaries 4 at the determined secondary voltage V(n) and the chip loss (conduction loss + switching loss) in each boost mode for the total required output of the auxiliaries 4 at the determined secondary voltage V(n). In the example shown in Fig. 12, switching is performed between the one-phase boost mode and the two-phase boost mode when the total required output of the auxiliaries 4 is T2kW. In other words, when the total required output of the auxiliaries 4 is less than T2kW, the one-phase boost mode is selected, and when the total required output of the auxiliaries 4 is T2kW or more, the two-phase boost mode is selected.

[0058] Thereafter, the control unit 10 determines whether the variable n is 0 or not (S114), and if the result of this determination is YES, it increments the variable n (S112) and returns to step S102, and if the result of this determination is NO, it returns to step S101.

[0059] FIG. 13 is a flowchart showing the second boost control method of the first embodiment, and FIG. 14 is a diagram showing a method for determining the secondary voltage in the second boost control method.

[0060] In the boost control method 2, the control unit 10 determines the secondary voltage so as to minimize the total loss of the multiple auxiliaries 4, and selects the boost mode that minimizes the boost loss at the determined secondary voltage. This makes it possible to supply the power supplied from the charging facility to the auxiliaries 4 with high efficiency during charging at the second voltage (400V).

[0061] 13, during charging at the second voltage (400V), the control unit 10 sets a variable n to 0 (S201), and then samples the user-requested output for the auxiliary device 4 (S202). The sampling time for the user-requested output is, for example, about 20 msec. Since the electric vehicle of this embodiment is equipped with an electric compressor E-COMP, an electric heater ECH, and an auxiliary device converter DCDC as the auxiliary devices 4, the control unit 10 samples these user-requested outputs.

[0062] The control unit 10 samples the user-requested output for the auxiliary devices 4 (S202), and then calculates the loss for each auxiliary device 4 with respect to the user-requested output based on the efficiency map for each auxiliary device 4 shown on the left side of Fig. 14 (S203). Next, the control unit 10 calculates the secondary voltage V(n) at which the total loss P(n), which is the sum of the losses of each auxiliary device 4, is minimized, as shown on the right side of Fig. 14 (S204). In the example of Fig. 14, the secondary voltage V(n) is set to 800 V at which the total loss P(n) is minimized.

[0063] After calculating the secondary voltage V(n) (S204), the control unit 10 determines whether the variable n is equal to or greater than, for example, 3000 (cumulative calculation time 1 minute) (S205), and if the result of this determination is YES, determines the secondary voltage V(n) based on the calculation result of step S204 (S206). If the result of this determination is NO in step S205, the control unit 10 determines whether n=0 or whether the loss P(n)-P(0)<α (α is a negative threshold) is satisfied (S207), and if the result of this determination is YES, determines the secondary voltage V(n) based on the calculation result of step S204 (S206), but if the result of this determination is NO, the control unit 10 increments the variable n (S208) and returns to step S202. The processing in step S205 is intended to prevent frequent switching of control, and the processing in step S207 is intended to allow a change in the secondary voltage if the loss P(n) becomes lower than the threshold value α compared to the initial loss P(0) even if a predetermined time has not elapsed.

[0064] After determining the secondary voltage V(n) (S206), the control unit 10 calculates the loss during boosting at the determined secondary voltage V(n) and selects the boost mode that minimizes the loss (S209). The specific method for selecting the boost mode is the same as that of the boost control method 1 described in Fig. 12. Thereafter, the control unit 10 determines whether the variable n is 0 (S210), and if the determination result is YES, the control unit 10 increments the variable n (S208) and returns to step S102, and if the determination result is NO, returns to step S201.

[0065] FIG. 15 is a flowchart showing the boost control method 3 of the first embodiment, and FIG. 16 is a diagram showing a method for determining the secondary voltage and boost phase of the boost control method 3.

[0066] In the boost control method 3, the control unit 10 selects the secondary voltage and the boost mode based on the loss for each secondary voltage for the user-requested output of each auxiliary device 4 and the loss for each secondary voltage for each boost mode for the total value of the user-requested output of the auxiliary device 4. This makes it possible to supply the power supplied from the charging facility to the auxiliary device 4 with high efficiency during charging at the second voltage (400V).

[0067] Specifically, as shown in Fig. 15, the control unit 10 samples the user-requested output for the auxiliary equipment 4 during charging at the second voltage (400V) (S301). The sampling time for the user-requested output is, for example, 10 to 20 msec. Since the electric vehicle of this embodiment is equipped with an electric compressor E-COMP, an electric heater ECH, and an auxiliary equipment converter DCDC as the auxiliary equipment 4, the control unit 10 samples these user-requested outputs.

[0068] The control unit 10 samples the user-requested output for the auxiliary device 4 (S301), and then determines whether the user-requested output fluctuation is equal to or greater than a threshold value (S302). If the result of this determination is NO, the control unit 10 determines whether the accumulated sampling time is, for example, 1 minute or longer (S303). If either step S302 or S303 is YES, the control unit 10 proceeds to steps S304 and S305, but if the result of the determination in step S303 is NO, the control unit 10 returns to step S302. The processing in steps S302 and S303 is intended to prevent frequent switching of control.

[0069] The control unit 10 executes steps S304 and S305 in parallel. In step S304, the control unit 10 calculates the loss for each secondary voltage with respect to the user-requested output of each auxiliary device 4 based on the efficiency map of each auxiliary device 4 shown on the left side of Fig. 16. In step S305, the control unit 10 calculates the loss for each secondary voltage in each boost mode with respect to the total value of the user-requested output of the auxiliary device 4 based on the efficiency map of each boost mode shown in the upper right of Fig. 16. After calculating the sum of the losses calculated in steps S304 and S305 (S306), the control unit 10 determines the secondary voltage and boost mode that minimize the sum of losses (S307), as shown in the lower right of Fig. 16, and returns to step S301.

[0070] [Second embodiment] Next, a charging system 1 of a second embodiment will be described with reference to Figures 17 to 21. However, for configurations common to the first embodiment, the same reference numerals as in the first embodiment are used, and the description of the first embodiment may be used.

[0071] FIG. 17 is a schematic diagram showing a schematic configuration of a charging system 1 according to the second embodiment. As shown in FIG. 17, the charging system 1 of the second embodiment differs from the first embodiment in that a charging terminal 131P is connected to the neutral point 31 of the three-phase motor 3. Therefore, during charging at the second voltage (400 V) in the charging system 1 of the second embodiment, the charging system 1 is in the same state as in FIG. 6 except that the charging terminal 131P is connected to the neutral point 31 of the three-phase motor 3. Because the charging system 1 of the second embodiment has the charging terminal 131P connected to the neutral point 31 of the three-phase motor 3, the control unit 10 selects the number of coil phases available for boosting as the maximum number of selectable phases, three phases (U, V, and W). The control unit 10 selects the one-phase boost mode when the number of selected phases is one, selects the two-phase boost mode when the number of selected phases is two, and selects the three-phase boost mode when the number of selected phases is three.

[0072] FIG. 18 is a diagram showing the current flow during three-phase voltage step-up during charging at the second voltage (400 V) in the charging system 1 of the second embodiment. 6, the control unit 10 performs a boost operation by switching the first low-side switch TL1, the second low-side switch TL2, and the third low-side switch TL3 at high frequency to switch between the ON state of the first low-side switch TL1, the second low-side switch TL2, and the third low-side switch TL3 and the OFF state of the first low-side switch TL1, the second low-side switch TL2, and the third low-side switch TL3. The other switches TH1 to TH3 of the inverter 5 are maintained in the OFF state.

[0073] As a result, the energy stored in coils 32U, 32V, and 32W when the first low-side switch TL1, the second low-side switch TL2, and the third low-side switch TL3 are in the ON state is released when the first low-side switch TL1, the second low-side switch TL2, and the third low-side switch TL3 are in the OFF state, and the 400V voltage supplied from the charging terminals 131P and 131N is boosted to a secondary voltage and supplied from the inverter 5 to the auxiliary device 4. Hereinafter, this boost operation state by the three-phase motor 3 and the inverter 5 is referred to as a three-phase boost mode.

[0074] FIG. 19 is a diagram showing the current flow during two-phase boost charging at the second voltage (400 V) in the charging system 1 of the second embodiment. 6, the control unit 10 performs a boost operation by switching the second low-side switch TL2 and the third low-side switch TL3 at high frequency to switch between the ON state of the second low-side switch TL2 and the third low-side switch TL3 and the OFF state of the second low-side switch TL2 and the third low-side switch TL3. Note that the other switches TL1 and TH1 to TH3 of the inverter 5 are maintained in the OFF state.

[0075] As a result, the energy stored in coils 32V, 32W when the second low-side switch TL2 and the third low-side switch TL3 are in the ON state is released when the second low-side switch TL2 and the third low-side switch TL3 are in the OFF state, and the 400V voltage supplied from the charging terminals 131P, 131N is boosted to a secondary voltage and supplied from the inverter 5 to the auxiliary device 4. Hereinafter, this boost operation state by the three-phase motor 3 and the inverter 5 is referred to as a two-phase boost mode. Note that, although the present example illustrates the case where the V phase and the W phase are selected, the selected phases may be the U phase and the V phase, or the U phase and the W phase.

[0076] FIG. 20 is a diagram showing the current flow during one-phase boosting during charging at the second voltage (400 V) in the charging system 1 of the second embodiment. 6, the control unit 10 performs a boost operation by switching the third low-side switch TL3 between an ON state and an OFF state by high-frequency switching of the third low-side switch TL3. Note that the other switches TL1, TL2, and TH1 to TH3 of the inverter 5 are maintained in the OFF state.

[0077] As a result, the energy stored in coil 32W when third low-side switch TL3 is in the ON state is released when third low-side switch TL3 is in the OFF state, and the 400 V voltage supplied from charging terminals 131P, 131N is boosted to a secondary voltage and supplied from inverter 5 to auxiliary device 4. Hereinafter, this boost operation state by three-phase motor 3 and inverter 5 is referred to as one-phase boost mode. Note that, although the W phase is selected in this example, the U phase or the V phase may also be selected.

[0078] When charging to the second voltage (400V), the control unit 10 boosts the power supplied to the auxiliary device 4 in any one of the three-phase boost mode, two-phase boost mode, and one-phase boost mode described above, by determining the secondary voltage based on the operation requirement information of the auxiliary device 4 and selecting the boost mode to be used for boosting based on the determined secondary voltage. At this time, the control unit 10 selects the boost mode that minimizes the boost loss at the determined secondary voltage.

[0079] Specifically, as with the charging system 1 of the first embodiment, any one of the three boost control methods 1 to 3 can be employed. However, while the method for determining the boost phase for the boost control methods 1 and 2 in the first embodiment uses the map shown in Fig. 12 that compares the total losses in the one-phase boost mode and the two-phase boost mode, the method for determining the boost phase for the boost control methods 1 and 2 in the second embodiment can use the map shown in Fig. 21 that compares the total losses in the one-phase boost mode, the two-phase boost mode, and the three-phase boost mode.

[0080] For example, as shown in Fig. 21, a boost mode is selected that provides the smallest total loss, which is the sum of the copper loss in each boost mode for the total required output of the auxiliaries 4 at the determined secondary voltage and the chip loss (conduction loss + switching loss) in each boost mode for the total required output of the auxiliaries 4 at the determined secondary voltage. In the example shown in Fig. 21, switching between the one-phase boost mode and the two-phase boost mode occurs when the total required output of the auxiliaries 4 is T3kW, and switching between the two-phase boost mode and the three-phase boost mode occurs at T4kW. In other words, when the total required output of the auxiliaries 4 is less than T3kW, the one-phase boost mode is selected, when the total required output of the auxiliaries 4 is T3kW or more but less than T4kW, the two-phase boost mode is selected, and when the total required output of the auxiliaries 4 is T4kW or more, the three-phase boost mode is selected.

[0081] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0082] This specification describes at least the following items. Note that the components in parentheses correspond to those in the above-described embodiment, but are not limited to these.

[0083] (1) Battery (Battery 2) and an auxiliary device (auxiliary device 4) that is driven by power supplied from the battery when the battery is discharging, and to which the supply of power from the battery is cut off when the battery is charging; a DC voltage conversion unit (three-phase motor 3, inverter 5) that converts the DC voltage of the charging equipment side into an auxiliary side voltage (auxiliary drive voltage, secondary voltage) different from the battery voltage and supplies it to the auxiliary; A vehicle charging system (charging system 1) including a control unit (control unit 10) that controls the DC voltage conversion unit, the DC voltage conversion unit includes a plurality of phase coils (coils 32U, 32V, 32W) and a conversion unit (switches TH1 to TH3, TL1 to TL3) provided for each of the plurality of phases, the control unit has a phase number selection unit that selects the number of phases to be driven from the plurality of phases, The number-of-phases selection unit determining the auxiliary side voltage from the operation request information of the auxiliary; determining the number of phases to be driven based on the auxiliary side voltage; a charging system that drives the determined number of phases and supplies power to the auxiliary equipment;

[0084] According to (1), when the battery voltage and the auxiliary equipment voltage are different, the number of phases to be energized among the multiple phase coils that make up the DC voltage conversion unit can be set according to the auxiliary equipment's operating requirement information, thereby making it possible to supply power to the auxiliary equipment with high efficiency during charging.

[0085] (2) The charging system according to (1), The auxiliary machine is provided in plurality, the phase number selection unit determines the auxiliary side voltage so as to minimize loss in an auxiliary device having the highest output among the plurality of auxiliary devices. Charging system.

[0086] According to (2), the auxiliary voltage is determined so as to minimize the loss of the high-output auxiliary equipment, which has a large influence, and therefore the control can be simplified.

[0087] (3) The charging system according to (1), the phase number selection unit selects an optimal number of phases based on the auxiliary side voltage and the required power of the auxiliary. Charging system.

[0088] According to (3), an appropriate number of phases can be selected taking into consideration the copper loss of the coil and the switching loss of the converter.

[0089] (4) The charging system according to (1), The auxiliary machine is provided in plurality, the phase number selection unit determines the auxiliary side voltage so as to minimize a total loss of the plurality of auxiliary machines. Charging system.

[0090] According to (4), the auxiliary side voltage is determined so as to minimize losses in the multiple auxiliary devices, so that an appropriate auxiliary side voltage can be determined.

[0091] (5) The charging system according to (1), a motor (three-phase motor 3) having the multiple phase coils (coils 32U, 32V, 32W) driven by power supplied from the battery; an inverter (inverter 5) having the conversion unit provided for each of the plurality of phases and converting DC power of the battery into AC power of the plurality of phases; the DC voltage conversion unit is configured with the multiple phase coils of the motor and the inverter; Charging system.

[0092] According to (5), the DC voltage conversion unit can be configured using the coil wound around the motor and the inverter conversion unit, eliminating the need for a dedicated voltage converter, which makes it possible to reduce the size and cost.

[0093] (6) A charging system according to any one of (1) to (5), a three-phase motor (three-phase motor 3) having three-phase coils (coils 32U, 32V, 32W) driven by power supplied from the battery; A charging terminal (charging terminal 131P) is connected to the coil of one phase of the three-phase motor, the phase number selection unit selects the number of phases to be driven as the maximum number of phases that can be selected, that is, two phases to which the charging terminals are not connected. Charging system.

[0094] According to (6), voltage conversion can be performed in the more efficient mode of either the one-phase boost mode or the two-phase boost mode.

[0095] (7) A charging system according to any one of (1) to (5), a three-phase motor (three-phase motor 3) having three-phase coils (coils 32U, 32V, 32W) driven by power supplied from the battery; A charging terminal (charging terminal 131P) is connected to the neutral point (neutral point 31) of the three-phase motor, the phase number selection unit selects the number of phases to be driven as the maximum number of phases that can be selected from the three phases. Charging system.

[0096] According to (7), voltage conversion can be performed in the most efficient mode among the one-phase boost mode, the two-phase boost mode, and the three-phase boost mode.

[0097] (8) Battery (Battery 2), a three-phase motor (three-phase motor 3) having three-phase coils (coils 32U, 32V, 32W) driven by power supplied from the battery; an inverter (inverter 5) having a conversion unit (switches TH1 to TH3, TL1 to TL3) for each of the three phases, and converting the DC power of the battery into the three-phase AC power; an auxiliary device (auxiliary device 4) that is driven by power supplied from the battery when the battery is discharging, and to which the supply of power from the battery is cut off when the battery is charging; a DC voltage conversion unit including the three-phase coils of the three-phase motor and the conversion unit provided for each of the three phases of the inverter; a control unit (control unit 10) that controls charging of the battery; a charging terminal (charging terminal 131P) is connected between the coil of one of the three phases of the three-phase motor and the conversion unit of the one phase of the inverter; The control unit, when charging the battery, based on operation request information of the auxiliary device, a two-phase boost mode in which the other two phases of the three-phase coils of the three-phase motor are driven to boost the charging voltage; a one-phase boost mode in which one of the other two phases of the three-phase coil of the three-phase motor is driven to boost the charging voltage, and power is supplied to the auxiliary equipment by selecting the one-phase boost mode. Charging system.

[0098] According to (8), when the battery voltage and the auxiliary voltage differ, by setting the number of phases of the three-phase motor coils that make up the DC voltage converter according to the operation requirement information of the auxiliary, it is possible to convert voltage in the most efficient mode, either one-phase boost mode or two-phase boost mode, and to supply power to the auxiliary with high efficiency during charging. In addition, since the DC voltage converter can be configured using the coils wound around the motor and the inverter conversion unit, a dedicated voltage converter is not required. This makes it possible to reduce size and cost.

[0099] (9) a battery (battery 2); a three-phase motor (three-phase motor 3) having three-phase coils (coils 32U, 32V, 32W) driven by power supplied from the battery; an inverter (inverter 5) having a conversion unit (switches TH1 to TH3, TL1 to TL3) for each of the three phases, and converting the DC power of the battery into the three-phase AC power; an auxiliary device (auxiliary device 4) that is driven by power supplied from the battery when the battery is discharging, and to which the supply of power from the battery is cut off when the battery is charging; a DC voltage conversion unit including the three-phase coils of the three-phase motor and the conversion unit provided for each of the three phases of the inverter; a control unit (control unit 10) that controls charging of the battery; A charging terminal (charging terminal 131P) is connected to the neutral point (neutral point 31) of the three-phase coil of the three-phase motor, The control unit, when charging the battery, based on operation request information of the auxiliary device, a three-phase boost mode in which the coils of the three phases of the three-phase motor are driven to boost a charging voltage; a two-phase boost mode in which any two of the three-phase coils of the three-phase motor are driven to boost the charging voltage; a one-phase boost mode in which one of the three-phase coils of the three-phase motor is driven to boost the charging voltage, and the power is supplied to the auxiliary equipment by selecting the one-phase boost mode. Charging system.

[0100] According to (9), when the battery voltage and the auxiliary equipment voltage are different, by setting the number of phases of the three-phase motor coils that make up the DC voltage converter according to the operation requirement information of the auxiliary equipment, it is possible to convert the voltage in the most efficient mode out of one-phase boost mode, two-phase boost mode, and three-phase boost mode, and to supply power to the auxiliary equipment with high efficiency during charging.In addition, since the DC voltage converter can be configured using the coils wound around the motor and the conversion unit of the inverter, a dedicated voltage converter is not required.This makes it possible to reduce the size and cost. [Explanation of symbols]

[0101] 1 Charging System 2 Battery 3 3-phase motor (DC voltage conversion section) 31 Neutral point 32U, 32V, 32W coil 4 Auxiliary equipment 5 Inverter (DC voltage conversion section) 10 Control Unit 31 Neutral point 131P charging terminal TH1~TH3, TL1~TL3 switch (conversion section)

Claims

1. A battery, an auxiliary device that is driven by power supplied from the battery when the battery is discharging, and to which power supply from the battery is cut off when the battery is charging; a DC voltage conversion unit that converts a DC voltage on the charging equipment side into an auxiliary side voltage different from a battery voltage and supplies the auxiliary side voltage to the auxiliary; a control unit that controls the DC voltage conversion unit, the DC voltage converter includes a plurality of phase coils and a converter provided for each of the plurality of phases, the control unit has a phase number selection unit that selects the number of phases to be driven from the plurality of phases, The number-of-phases selection unit determining the auxiliary side voltage from the operation request information of the auxiliary; determining the number of phases to be driven based on the auxiliary side voltage; a charging system that drives the determined number of phases and supplies power to the auxiliary equipment;

2. 2. The charging system according to claim 1, The auxiliary machine is provided in plurality, the phase number selection unit determines the auxiliary side voltage so as to minimize loss in an auxiliary device having the highest output among the plurality of auxiliary devices. Charging system.

3. 2. The charging system according to claim 1, the phase number selection unit selects an optimal number of phases based on the auxiliary side voltage and the required power of the auxiliary. Charging system.

4. 2. The charging system according to claim 1, The auxiliary machine is provided in plurality, the phase number selection unit determines the auxiliary side voltage so as to minimize a total loss of the plurality of auxiliary machines. Charging system.

5. 2. The charging system according to claim 1, a motor having the multi-phase coils and driven by power supplied from the battery; an inverter having the conversion unit provided for each of the plurality of phases, and converting DC power of the battery into AC power of the plurality of phases; the DC voltage conversion unit is configured with the multiple phase coils of the motor and the inverter; Charging system.

6. The charging system according to any one of claims 1 to 5, a three-phase motor having three-phase coils that is driven by power supplied from the battery; a charging terminal is connected to the coil of one phase of the three-phase motor; the phase number selection unit selects the number of phases to be driven as the maximum number of phases that can be selected, that is, two phases to which the charging terminals are not connected. Charging system.

7. The charging system according to any one of claims 1 to 5, a three-phase motor having three-phase coils that is driven by power supplied from the battery; A charging terminal is connected to the neutral point of the three-phase motor, the phase number selection unit selects the number of phases to be driven as the maximum number of phases that can be selected from the three phases. Charging system.

8. A battery, a three-phase motor having three-phase coils that is driven by power supplied from the battery; an inverter having a conversion unit for each of the three phases, which converts DC power from the battery into AC power of the three phases; an auxiliary device that is driven by power supplied from the battery when the battery is discharging, and to which power supply from the battery is cut off when the battery is charging; a DC voltage conversion unit including the three-phase coils of the three-phase motor and the conversion unit provided for each of the three phases of the inverter; a control unit that controls charging of the battery, a charging terminal is connected between the coil of one of the three phases of the three-phase motor and the conversion unit of the one phase of the inverter; The control unit, when charging the battery, based on operation request information of the auxiliary device, a two-phase boost mode in which the other two phases of the three-phase coils of the three-phase motor are driven to boost a charging voltage; a one-phase boost mode in which one of the other two phases of the three-phase coil of the three-phase motor is driven to boost the charging voltage, and power is supplied to the auxiliary equipment by selecting the one-phase boost mode. Charging system.

9. A battery, a three-phase motor having three-phase coils that is driven by power supplied from the battery; an inverter having a conversion unit for each of the three phases, which converts DC power from the battery into AC power of the three phases; an auxiliary device that is driven by power supplied from the battery when the battery is discharging, and to which power supply from the battery is cut off when the battery is charging; a DC voltage conversion unit including the three-phase coils of the three-phase motor and the conversion unit provided for each of the three phases of the inverter; a control unit that controls charging of the battery, a charging terminal is connected to the neutral point of the three-phase coil of the three-phase motor; The control unit, when charging the battery, based on operation request information of the auxiliary device, a three-phase boost mode in which the coils of the three phases of the three-phase motor are driven to boost a charging voltage; a two-phase boost mode in which any two of the three-phase coils of the three-phase motor are driven to boost the charging voltage; a one-phase boost mode in which one of the three-phase coils of the three-phase motor is driven to boost the charging voltage, and power is supplied to the auxiliary equipment by selecting the one-phase boost mode. Charging system.

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