Charging system

Abstract

Even when two or more inverter circuits are provided, it is not necessary to use high-durability components for only one of the inverters. [Solution] A charging system comprising at least two inverter circuits, wherein the usage time of each inverter circuit is compared and charging is performed using the inverter circuit with the shortest usage time.

Description

Technical Field

[0001] The present disclosure relates to a charging system.

Background Art

[0002] Patent Document 1 below discloses a magnetic resonance charging system including a voltage source and an inverter, where the inverter includes a parallel LC inverter resonance circuit and at least one charging plate. The inverter resonance circuit includes a capacitor connected in parallel with the primary winding of at least one charging plate. The inverter further includes measuring means for measuring the instantaneous voltage at both ends of the inverter resonance circuit, a phase shifter connected to the measuring means, and excitation means connected to the phase shifter for injecting energy from the voltage source into the inverter resonance circuit during each cycle observed by the measuring means with the phase shift indicated by the phase shifter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, when constructing a system provided with two or more inverter circuits, there is no disclosure on how to use these inverter circuits for charging. For example, when performing neutral point charging in a two-inverter system, only the circuit on the first inverter side is used to perform step-up charging. Since only the components on the first inverter side need to be high-durability components, the cost of the unit becomes high, which is a problem.

[0005] This disclosure aims to eliminate the need to use high-durability components for only one inverter, even when two or more inverter circuits are provided. [Means for solving the problem]

[0006] This disclosure relates to a charging system comprising at least two inverter circuits, wherein the usage time of each inverter circuit is compared, and charging is performed using the inverter circuit with the shortest usage time. [Effects of the Invention]

[0007] According to this disclosure, even if two or more inverter circuits are provided, it is not necessary to use high-durability components for only one of the inverters. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a flowchart illustrating the operation of the charging system according to this embodiment. [Figure 2] Figure 2 shows an example of the energized state of the charging system according to this embodiment. [Figure 3] Figure 3 shows an example of the energized state of the charging system according to this embodiment. [Modes for carrying out the invention]

[0009] This embodiment will now be described with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations are omitted.

[0010] Figure 1 is a flowchart illustrating the operation of the charging system 2 according to this embodiment. The configuration of the charging system 2 is illustrated in Figures 2 and 3. As shown in Figures 2 and 3, the charging system 2 is a system that can drive a motor having windings L1, L2, and L3, and can also charge a battery 30 using a charger 24.

[0011] The charging system 2 includes a first inverter 21, a second inverter 22, an ECU (Electronic Control Unit) 23, and a charger 24. The charging system 2 includes a battery 30 and a motor having windings L1, L2, L3. The charging system 2 includes relays R1, R2, R3, R4, R5, R6. The charging system 2 includes switching elements 25a, 25b, 25c.

[0012] The first inverter 21 includes switching elements 21a, 21b, 21c, 21d, 21e, 21f and a capacitor 21g. The second inverter 22 includes switching elements 22a, 22b, 22c, 22d, 22e, 22f and a capacitor 22g.

[0013] The first inverter 21 has a DC terminal to which a DC voltage formed between the positive and negative terminals of the battery 30 is applied, and an AC terminal connected to each of the motor windings L1 to L3. Two nodes to which the first inverter 21 is connected to either the positive or negative terminal of the battery 30 can be DC terminals, and three nodes to which the first inverter 21 is connected to one of the motor windings L1 to L3 can be AC ​​terminals.

[0014] The second inverter 22 has a DC end that is selectively connected to the DC end of the first inverter 21, and an AC end that is connected to each of the motor windings L1 to L3. The second inverter 22 can have two DC ends, including one node that is selectively connected to the DC end of the first inverter 21, or it can have three AC ends, which are connected to the other ends of each of the motor windings L1 to L3.

[0015] In the motor drive mode, which generates power to drive the vehicle with a motor, the DC terminals of the first inverter 21 and the second inverter 22 are commonly connected to the battery 30. They can convert the DC power stored in the battery 30 into three-phase AC power and supply it to the motor, or convert the regenerative braking energy generated by the regenerative braking torque of the motor during regenerative braking into DC power and supply it to the battery 30. Such conversion between DC power and AC power can be performed by pulse width modulation control of multiple switching elements 21a, 21b, 21c, 21d, 21e, 21f and multiple switching elements 22a, 22b, 22c, 22d, 22e, 22f provided in the first inverter 21 and the second inverter 22, respectively.

[0016] In a charging mode for charging the battery 30, the ECU 23 can control the multiple switching elements 21a, 21b, 21c, 21d, 21e, 21f and the multiple switching elements 22a, 22b, 22c, 22d, 22e, 22f included in the first inverter 21 and the second inverter 22 so that a DC charging voltage is applied between the other ends of the multiple switching elements 25a, 25b, 25c and the negative terminal of the battery 30, and the magnitude of the DC charging voltage is converted based on the magnitude of the DC charging voltage and provided to the battery 30.

[0017] The DC power supplied from the charger 24 can be applied between a node in which multiple switching elements 25a, 25b, and 25c are interconnected and a node connected to the negative terminal of the battery 30. In other words, the charging voltage supplied from the charger 24 can be applied between a node in which multiple switching elements 25a, 25b, and 25c are interconnected and a node connected to the negative terminal of the battery 30.

[0018] To form / disconnect the electrical connection between the charger 24 and the motor drive system, one embodiment of the present invention may further include relays R1, R2, R3, R4, R5, R6.

[0019] Therefore, when the charger 24 is connected to the vehicle for charging, when the ECU 23 turns on the switching elements 25a, 25b, 25c and the relays R4, R5, R6, the neutral ends N of the motor windings L1 to L3 are formed at the other ends of the switching elements 25a, 25b, 25c.

[0020] As shown in FIG. 2, the ECU 23 can control the relays R1, R2, R4, R5 to be in a short - circuit state in the charging mode, and control the switching elements 25a, 25b, 25c to maintain a short - circuit state. The ECU 23 can control the switching elements 21a, 21b, 21c of the first inverter 21 to maintain a short - circuit state, and control the switching elements 21d, 21e, 2,f to maintain an open state. The ECU 23 can control all the switching elements 22a, 22b, 22c, 22d, 22e, 22f of the second inverter 22 to maintain an open state.

[0021] Thereby, the motor windings L1 to L3, the switching elements 21a, 21b, 21c of the first inverter 21, and the switching elements 25a, 25b, 25c can boost the voltage in the direction from the charger 24 to the battery 30. In the boost circuit shown in FIG. 2, the capacitor 21g serves as the capacitor used for boosting.

[0022] Subsequently, referring to FIG. 3, the charging control using the second inverter 22 will be described. As shown in FIG. 3, the ECU 23 can control the relays R1, R2, R4, R5, R6 to be in a short - circuit state in the charging mode, and control the switching elements 25a, 25b, 25c to maintain an open state. The ECU 23 can control the switching elements 21a, 21b, 21c of the first inverter 21 to maintain an open state, and control the switching elements 21d, 21e, 21f to maintain a short - circuit state. The ECU 23 can control the switching elements 22a, 22b, 22c of the second inverter 22 to maintain a short - circuit state, and control the switching elements 22d, 22e, 22f to maintain an open state.

[0023] Thereby, the motor windings L1 to L3, the switching elements 21d, 21e, 21f of the first inverter 21, and the switching elements 22a, 22b, 22c of the second inverter 22 can boost the voltage in the direction from the charger 24 to the battery 30. In the boost circuit shown in FIG. 3, the capacitor 22g serves as the capacitor used for boosting.

[0024] Referring to FIG. 1, the control flow of the ECU 23 will be described. In step S01, the ECU 23 determines whether the usage time of the first inverter 21 is longer than the usage time of the second inverter 22 during neutral point charging. The usage time is calculated by the ECU 23 integrating the total charging time of each inverter. If the usage time of the first inverter 21 is longer (step S01: YES), the process proceeds to step S02. If the usage time of the first inverter 21 is not longer (step S01: NO), the process proceeds to step S03.

[0025] In step S02, the ECU 23 executes charging control using the second inverter 22 as described with reference to FIG. 3. In step S03, the ECU 23 executes charging control using the first inverter 21 as described with reference to FIG. 2.

[0026] In step S04 following steps S02 and S03, the ECU 23 calculates the charging circuit switching time t. The charging circuit switching time t is calculated, for example, from the inverter water temperature and the current sensor value at the start of charging. The ECU 23 acquires in advance the time to reach the heat-resistant temperature of the capacitor under a plurality of conditions with the inverter water temperature and the current value mapped, and calculates the charging circuit switching time t using the mapped data.

[0027] In step S05, following step S04, the ECU23 determines whether the charging time is t seconds or more. The ECU23 accumulates the charging time of the inverter and determines whether it is equal to or greater than the charging circuit switching time t calculated in step S04. If the charging time is t seconds or more (step S05: YES), the process proceeds to step S07. If the charging time is not t seconds or more (step S05: NO), the process proceeds to step S06.

[0028] In step S06, ECU23 continues charging with the selected inverter. In step S07, ECU23 starts charging with the other inverter that was not selected.

[0029] In step S08, following steps S06 and S07, the ECU23 determines whether the State of Charge (SOC) of the battery 30 is fully charged. If the SOC of the battery 30 is fully charged (step S08: YES), charging stops. If the SOC of the battery 30 is not fully charged (step S08: NO), the process proceeds to step S05.

[0030] The electronic control unit (ECU) and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the electronic control unit (ECU) and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the electronic control unit (ECU) and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium.

[0031] The embodiments have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise.

[0032] [Note] [Note 1] A charging system comprising at least two inverter circuits, A charging system that compares the usage time of each inverter circuit and performs charging using the inverter circuit with the shortest usage time.

[0033] Since the operating time of two or more inverter circuits can be equalized, there is no need to make only one of the inverter circuits highly durable, which can reduce the cost of the inverter circuits. [Explanation of symbols]

[0034] 2: Charging system 21: First Inverter 22: Second Inverter 23:ECU(Electronic Control Unit) 24: Charger 30: Battery 21a, 21b, 21c, 21d, 21e, 21f: Switching elements 21g: Capacitor 22a, 22b, 22c, 22d, 22e, 22f: Switching elements 22g: Capacitor 25a, 25b, 25c: Switching elements L1, L2, L3: Windings R1, R2, R3, R4, R6, R6: Relay

Claims

[Claim 1] A charging system comprising at least two inverter circuits, A charging system that compares the usage time of each of the aforementioned inverter circuits and performs charging using the inverter circuit with the shortest usage time.

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