Vehicle-mounted charging device

Abstract

The invention provides an on-board charging device which can charge an on-board DC power supply through an external AC power supply by using a vehicle driving device and can output AC power from the DC power supply. The present invention is provided with an AC / DC converter (1) for converting power between an AC power on the side of an external AC power source (4) and a first DC power, and a DC / DC converter (2) for converting power between the first DC power and a second DC power on the side of a DC power source (3), the AC / DC converter (1) being provided with: a current source active rectifier (17) having a power factor improvement function; the DC-DC converter (2) is provided with a chopper circuit provided with a reactor disposed on the AC-DC converter (1) side, and a half-bridge circuit disposed on the DC power supply (3) side, the reactor being configured using a plurality of coils (7), the half-bridge circuit being configured using an inverter (5), and the current source active rectifier (17) being configured using a bidirectional switching element.

Description

Technical Field

[0001] The invention relates to a vehicle-mounted charging device. Background Art

[0002] Christelle Saber et al. published a paper on an on-board charger for charging batteries (DC power supply) for electric vehicles. Saber et al. studied the power factor improvement (PFC: Power Factor Correct) in on-board chargers with reduced costs by using components of a vehicle traction power train in the on-board charger. Fig.16 As shown, the on-vehicle charging device studied by Saber et al. is provided with a unidirectional current source active rectifier 17 (CSAR: Current Source Active Rectifier) ​​having a step-down function at the input stage (AC-DC converter 1) from the external AC power source 4, and a boost converter (boost converter) is provided at the output stage (DC-DC converter 2) to the DC power source 3 following the CSAR. That is, the on-vehicle charging device is disclosed, which arranges the AC-DC step-down converter and the DC-DC step-up converter in this order from the external AC power source 4 to the DC power source 3.

[0003] In this paper, Saber et al. studied a vehicle-mounted charging device that supplies power from a single-phase external AC power source 4. In Japanese Patent Publication No. 2011-526775 (same family: U.S. Patent Application Publication No. 2012 / 0286740), as shown in FIG. Fig.17 , an example of an on-vehicle charging device supplied with power from a three-phase external AC power source 4 is disclosed. This on-vehicle charging device also has a structure in which an AC-DC buck converter and a DC-DC boost converter are arranged in order from the external AC power source 4 to the DC power source 3.

[0004] Patent Document 1: Japanese Patent Application No. 2011-526775

[0005] Non-patent document 1: Christelle Saber, Denis Labrousse, Bertrand Revol, and Alain Gascher "Challenges Facing PFC of a Single-Phase On-Board Charger for ElectricVehicles Based on a Current Source Active Rectifier Input Stage", IEEETRANSACTIONS ON POWER ELECTRONICS, Vol.31, No.9, September 2016, P.6192-6202

[0006] However, in recent years, it has been proposed to use the DC power supply of electric vehicles and hybrid vehicles as an emergency AC power supply in times of disasters. Fig.16 , Fig.17 The above-mentioned on-vehicle charging device only supports unidirectional power supply from the external AC power supply to the DC power supply. Summary of the invention

[0007] In view of the above background, it is desirable to provide an in-vehicle charging device that can also utilize an in-vehicle drive device to charge an in-vehicle DC power supply from an external AC power supply and can output AC power from the DC power supply.

[0008] In view of the above situation, the vehicle-mounted charging device is mounted on a vehicle that includes: a rotating electric machine that includes multi-phase coils that are connected to each other at a neutral point and serve as a driving force source for wheels, an inverter that converts power between direct current and multi-phase alternating current, and a direct current power source connected to the rotating electric machine via the inverter, and the direct current power source is charged by power supplied from an external alternating current power source. The vehicle-mounted charging device includes: an AC-DC converter that converts power between alternating current on the external alternating current power source side and a first direct current; and a DC-DC converter that converts power between the first direct current and a second direct current on the direct current power source side. The AC-DC converter includes: a current source active rectifier with a power factor improvement function. The DC-DC converter includes a chopper circuit. The chopper circuit includes: an inductor that is arranged on the AC-DC converter side, and a half-bridge circuit that is arranged on the DC power source side. The inductor is configured using a plurality of the coils, the half-bridge circuit is configured using the inverter, and the current source active rectifier is configured using a bidirectional switching element.

[0009] According to this structure, the current source active rectifier with a power factor improvement function in the AC-DC converter is composed of a bidirectional switching element. That is, the current source active rectifier is constructed using a bidirectional switching element as a switching element. The bidirectional switching element is an element that can make current flow in both directions, and for the element, it has the same withstand voltage for positive and negative polarity voltages. Therefore, it is easy to construct an AC-DC converter with a current-controlled active rectification circuit. In a voltage-controlled AC-DC converter, a large-capacity capacitor is required, but by setting it as a current-controlled AC-DC converter, it is possible to reduce component costs and suppress large-scale equipment without the need for a large-capacity capacitor. In addition, the current source active rectifier constructed using a bidirectional switching element is a current source active rectifier that can perform power conversion in both directions. Therefore, not only can power conversion from AC to DC be performed, but power conversion from DC to AC can also be performed. Therefore, the DC power supply of electric vehicles and hybrid vehicles can also be used as an emergency AC power supply. Thus, according to this configuration, it is possible to provide an on-vehicle charging device that can also utilize the vehicle drive device to charge the on-vehicle DC power supply with the external AC power supply and output AC power from the DC power supply.

[0010] Further features and advantages of the on-vehicle charging device will become apparent from the following description of exemplary and non-limiting embodiments explained with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic circuit block diagram of a drive control system for a rotating electrical machine.

[0012] Figure 2 This is a circuit block diagram showing a first example of an on-vehicle charging device using a drive control system of a rotating electrical machine.

[0013] Figure 3 This is a diagram showing a positive current loop when charging an output capacitor in an on-vehicle charging device functioning as an AC-DC step-down converter when charging a DC power supply.

[0014] Figure 4 The diagram shows a positive current circulation loop in a vehicle-mounted charging device functioning as an AC-DC step-down converter.

[0015] Figure 5 This is a diagram showing a negative current loop when charging an output capacitor in an on-vehicle charging device functioning as an AC-DC step-down converter when charging a DC power supply.

[0016] Figure 6 This is a diagram showing a negative current circulation loop in a vehicle-mounted charging device functioning as an AC-DC step-down converter.

[0017] Figure 7 This is a diagram showing a positive current loop when charging a reactor in an on-vehicle charging device functioning as an AC-DC boost converter when charging a DC power supply.

[0018] Figure 8 The diagram shows a positive current circulation loop in a vehicle-mounted charging device functioning as an AC / DC boost converter.

[0019] Fig. 9 This is a diagram showing a negative current loop when charging a reactor in an on-vehicle charging device functioning as an AC-DC boost converter when charging a DC power supply.

[0020] Fig.10 The diagram shows a negative current circulation loop in a vehicle-mounted charging device functioning as an AC / DC boost converter.

[0021] Fig.11 1 is a circuit block diagram showing a second example of the vehicle-mounted charging device using the drive control system of the rotating electric machine.

[0022] Fig.12 1 is a circuit block diagram showing a third example of the vehicle-mounted charging device using the drive control system of the rotating electrical machine.

[0023] Fig.13 1 is a diagram showing an example of a positive current loop when the on-vehicle charging device of the third example is supplied with electric power from a three-phase external DC power supply.

[0024] Fig.14 FIG. 1 is a diagram showing an example of a positive current circulation circuit in the vehicle-mounted charging device of the third example.

[0025] Fig.15 This is a diagram showing an example of a positive current loop when the on-vehicle charging device of the third example is supplied with electric power from a single-phase external DC power supply.

[0026] Fig.16 This is a circuit block diagram showing a conventional example of a charging device that charges a DC power source with electric power from a single-phase AC external power source and utilizes a drive control system for a rotating electrical machine.

[0027] Fig.17 This is a circuit block diagram showing a conventional example of a charging device that charges a DC power source with electric power from a three-phase AC external power source and utilizes a drive control system for a rotating electric machine.

[0028] Description of Reference Numerals

[0029] 1: AC-DC converter, 2: DC-DC converter, 3: DC power supply, 4: external AC power supply, 4N: neutral point, 5: inverter, 7: coil, 10: on-board charger, 17: current source active rectifier, 70: rotating motor, Le: inductor. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the vehicle-mounted charging device will be described with reference to the drawings. Figure 1 The circuit block diagram schematically shows the drive control system of the rotating electrical machine 70. Figure 2 The circuit block diagram of FIG. 1 shows a first example of a vehicle-mounted charging device 10 using a drive control system of a rotating electric machine 70. The vehicle-mounted charging device 10 is a device that is mounted on a vehicle and is used to charge a rotating electric machine 70. Figure 1 A device for charging the DC power supply 3 provided in the vehicle drive device 9 as shown. Figure 1 As shown, the vehicle drive device 9 of this embodiment includes a rotary electric machine 70 that is a driving force source for wheels of a hybrid vehicle, an electric vehicle, etc., an inverter 5 that converts electric power between direct current and multi-phase (here, three-phase) alternating current, and a direct current power source 3 connected to the inverter 5. In addition to the rotary electric machine 70, the vehicle drive device 9 may also include other driving force sources such as an internal combustion engine (not shown).

[0031] like Figure 2 As shown, the on-board charging device 10 is a device that charges the DC power supply 3 of the vehicle drive device 9 by power supplied from the external AC power supply 4 (grid power supply), and is a device called a so-called onboard charger (Onboard Charger). The on-board charging device 10 is configured to share a part with the vehicle drive device 9. Specifically, the inverter 5 and the coil 7 of the rotating motor 70 are shared. In addition, the DC link capacitor 6 is also shared as the output capacitor Cs of the on-board charging device 10. In addition, all or at least a part of the control devices not shown in the figure for controlling the switching elements, contactors, etc. of the on-board charging device 10 can also be shared with the control device 80 for controlling the vehicle drive device 9.

[0032] like Figure 1As shown, the vehicle drive device 9 includes a control device 80 that controls a rotating electric machine 70 that will be a driving force source of the vehicle. The control device 80 drives and controls the rotating electric machine 70 by performing current feedback control. The rotating electric machine 70 that is the driven object is a stator having a coil 7 (stator coil) of multiple phases (N is set to an arbitrary natural number, N phases, and in this embodiment, a three-phase form with N=3 is illustrated) arranged on a stator core, and a rotor having a permanent magnet arranged on a rotor core. Such a structure is well known, and in this embodiment, the stator core, stator, rotor core, rotor, permanent magnet, etc. are omitted. In this embodiment, a Y-type (star-type) form in which the three-phase coil 7 is short-circuited at the neutral point 7N is illustrated. However, the rotating electric machine 70 may also be a form that includes two sets of three-phase coils 7 and is driven by six-phase AC. In addition, the rotating electric machine 70 can function as both a motor and a generator. When the rotating electrical machine 70 functions as a motor, the rotating electrical machine 70 is in a power running state, and when the rotating electrical machine 70 functions as a generator, the rotating electrical machine 70 is in a regeneration state.

[0033] like Figure 1 As shown, the vehicle drive device 9 includes an inverter 5. The inverter 5 is connected to the AC rotating electric machine 70 and the DC power supply 3, and converts power between the multi-phase AC and DC. A pair of DC side terminals of the inverter 5 are connected to the positive terminal and the negative terminal of the DC power supply 3. In addition, the multi-phase AC side terminals of the inverter 5 are connected to each of the multi-phase coils 7. In the present embodiment, the inverter 5 is provided with a U-phase arm, a V-phase arm, and a W-phase arm as a multi-phase arm (also referred to as a leg). Each arm is formed by connecting the upper-side switching element arranged on the positive side and the lower-side switching element arranged on the negative side in series. The midpoint of each arm, that is, the connection point between the upper-side switching element and the lower-side switching element, is connected to each coil 7. Specifically, the midpoint of the U-phase arm is connected to the U-phase coil 7u, the midpoint of the V-phase arm is connected to the V-phase coil 7v, and the midpoint of the W-phase arm is connected to the W-phase coil 7w.

[0034] A smoothing capacitor (DC link capacitor 6) for smoothing the voltage (DC link voltage) between the positive and negative electrodes is provided on the DC side of the inverter 5. In addition, a voltage sensor (DC link voltage sensor 61) for detecting the DC link voltage is also provided on the DC side of the inverter 5. The DC link capacitor 6 is referred to as a "first DC link capacitor" in order to distinguish it from a capacitor (second DC link capacitor Cd) for smoothing the DC link voltage (first DC voltage) of the vehicle-mounted charger 10 described later.

[0035] The DC power supply 3 is composed of, for example, a rechargeable battery (battery) such as a lithium battery, a double-layer capacitor, or the like. As in the present embodiment, when the rotating electric machine 70 is the driving force source of the vehicle, the DC power supply 3 is a high-voltage and high-capacity DC power supply, and the rated power supply voltage is, for example, 200 to 800 [V]. In many cases, the DC power supply 3 is configured to be able to cut off or connect the electrical connection to the inverter 5 and the rotating electric machine 70 by operating the main switch (ignition switch) of the vehicle, etc. For example, the DC power supply 3 is connected to the inverter 5 and the rotating electric machine 70 via a main contactor 11 composed of a relay, etc. In addition, the DC power supply 3 is also provided with a current sensor (battery current sensor 31) for detecting the input and output current of the DC power supply 3 and a voltage sensor (battery voltage sensor 32) for detecting the terminal voltage of the DC power supply 3. In addition, the relay may be a mechanical relay or a semiconductor relay (solid-state relay). The same is true for other contactors below.

[0036] Although not shown in the figure, in the case where the DC power source 3 is a lithium battery, for example, a battery management system (BMS) is often provided. Rechargeable batteries such as lithium batteries are composed of a plurality of cells (battery cells). The battery management system is a battery management control system that performs (1) prevention of overcharging and overdischarging of cells, (2) prevention of overcurrent flowing in cells, (3) temperature management of cells, (4) calculation of the state of charge (SOC), and (5) equalization of cell voltages. The battery current sensor 31 and battery voltage sensor 32 may also constitute a part of the battery management system.

[0037] like Figure 1 As shown, the inverter 5 is composed of a plurality of switching elements 5S. In the present embodiment, a form in which a FET (Field Effect Transistor) is used as the switching element 5S is exemplified. In addition to FET, an IGBT (Insulated Gate Bipolar Transistor) may also be used as the switching element 5S. In addition, in the present embodiment, a freewheeling diode is connected in parallel with each switching element 5S in the direction from the negative electrode toward the positive electrode (from the lower side toward the upper side) as the forward direction. Of course, in the case of using a body diode, in the case of reverse conduction of a transistor using a wide bandgap semiconductor composed of enhanced gallium nitride (E-GaN), etc., such a freewheeling diode may not be provided.

[0038] like Figure 1As shown, the inverter 5 is controlled by the control device 80. The control device 80 is constructed with a logic circuit such as a microcomputer as a core component. For example, the control device 80 performs current feedback control based on the target torque (torque command) of the rotating electric machine 70 provided as a request signal from other control devices such as the vehicle control device 90 as one of the upper control devices, and drives the rotating electric machine 70 via the inverter 5. In addition, the operating voltage of the logic circuit element such as a microcomputer is generally less than 5 volts. In this embodiment, although the illustration is omitted for simplicity, the control signal generated by the logic circuit element is transmitted to the inverter 5 via the driver circuit. Or it can also be considered that the driver circuit is included in the control device 80.

[0039] The actual current flowing in the coil 7 of each phase of the rotating motor 70 is detected by the current sensor (motor current sensor 81), and the control device 80 obtains the detection result. In addition, the magnetic pole position (electrical angle) of the rotor of the rotating motor 70 at each moment and the rotation speed (angular velocity) of the rotor are detected by a rotation sensor 82 such as a resolver or an inductive position sensor (Inductive Position Sensor), and the control device 80 obtains the detection result. The control device 80 uses the detection results of the motor current sensor 81 and the rotation sensor 82 to perform current feedback control. The control device 80 is configured to have various functional units for current feedback control, and each functional unit is realized by the cooperation of hardware such as a microcomputer and software (program).

[0040] As described above, the rotating electric machine 70 connected to the DC power source 3 via the inverter 5 can function as a motor by the power supplied from the DC power source 3, and can function as a generator to charge the DC power source 3. For example, in a hybrid vehicle, mechanical energy can be supplied to the rotating electric machine 70 by the power of an internal combustion engine, etc., so that the rotating electric machine 70 generates electricity, but sometimes there are few opportunities for power generation, and the DC power source 3 cannot be fully charged. In addition, in an electric vehicle equipped with only the rotating electric machine 70 as a driving force source, the power generation of mechanical energy from the wheels such as inertial running is limited, and the DC power source 3 cannot be fully charged in many cases. In addition, even in a hybrid vehicle, the energy efficiency is often higher when power is supplied from the outside than when the rotating electric machine 70 generates electricity. Therefore, in a state where the DC power source 3 is mounted on the vehicle, it is preferably configured so that the DC power source 3 can be charged by an external power source.

[0041] When the DC power supply 3 is charged by an external power supply, it is preferred to mount an on-board charging device on the vehicle. In most cases, the external power supply receives power supply from an industrial power supply, so AC power is mostly used. Therefore, the on-board charging device is configured to have a power conversion function from AC to DC. As a circuit for converting power from AC to DC, an AC-DC converter having an inductor and a bridge circuit composed of switching elements is known. The conversion from AC to DC can also be achieved by using a rectifier circuit using a rectifier element such as a diode, but it is preferred to implement power conversion in a state where the power factor specified by the phase of the AC voltage and current is close to "1". Therefore, the AC-DC converter is mostly equipped with a power factor improvement (Power Factor Correction) circuit using a switching element in a manner that can improve the power factor.

[0042] The on-board charging device with such a power conversion circuit has a tendency to have a larger circuit scale, but the opportunity to charge the DC power supply 3 is less than the opportunity to drive the wheels. Therefore, it is preferred that the on-board charging device has a small-scale structure. When the DC power supply 3 is charged by an external power supply, the vehicle stops (parks). Therefore, the inverter 5 composed of a switching element and the coil 7 of the rotating motor 70 having an inductance are not used to drive the wheels when the DC power supply 3 is charged by an external power supply. Therefore, it is considered that the on-board charging device is formed by using the inverter 5 and the coil 7.

[0043] Fig.16 An existing on-board charging device (first charging device 10X) also illustrated in the background technology is shown. The same figure mark is also used in the position corresponding to the on-board charging device 10 of the present embodiment. The first charging device 10X also uses a transmission system (traction power train) for driving the wheels. Like the on-board charging device 10 of the present embodiment, the first charging device 10X also uses an inverter 5 (drive inverter (traction inverter)) and a coil 7 (rotating motor windings (electric machine windings)) at the output stage of the DC power supply 3, that is, the DC-DC converter 2. Coil 7 is the same as the on-board charging device 10 of the present embodiment and is used as a reactor (filtering inductor). The inverter 5 having a three-phase arm (also synonymous with a leg) is configured to uniformly control the switching elements on the upper side and uniformly control the switching elements on the lower side in a manner that appears to be an arm.

[0044] like Fig.16As shown, the first charging device 10X is provided with a unidirectional current source active rectifier 17 (CSAR: Current Source Active Rectifier) ​​having a step-down function at the input stage from the external AC power source 4, that is, the AC-DC converter 1. The current source active rectifier has a full-bridge circuit using a switching element, and is configured as a totem pole type power factor improvement circuit. One arm of the full-bridge circuit is configured to be connected in sequence from the positive side of the DC to the negative side, with a diode connected to the cathode and the positive side, two switching elements connected in parallel with a freewheeling diode in the direction from the positive side to the negative side as the forward direction, and a diode connected to the anode and the negative side. A filter 1f (inductor / capacitor / filter) composed of a filter inductor Lf and a filter capacitor Cf is arranged between the external AC power source 4 and the current source active rectifier 17. In addition, a differential mode inductor Lg is arranged between the filter 1f and the external AC power source 4.

[0045] Although detailed description is omitted, Fig.17 The same applies to the vehicle-mounted charging device (second charging device 10Y) shown above, which charges the DC power source 3 with electric power from the three-phase external AC power source 4 .

[0046] In the present embodiment, the vehicle-mounted charging device 10 is configured as follows, and is mounted on a vehicle including: a rotating electric machine 70 having multi-phase coils 7 connected to each other at a neutral point 7N and serving as a driving force source for wheels, an inverter 5 for converting power between direct current and multi-phase alternating current, and a direct current power source 3 connected to the rotating electric machine 70 via the inverter 5, and the direct current power source 3 is charged by power supplied from an external alternating current power source 4. That is, as Figure 2 As shown, the vehicle-mounted charging device 10 includes an AC-DC converter 1 for converting power between the AC power on the external AC power source 4 side and the first DC power, and a DC-DC converter 2 for converting power between the first DC power and the second DC power on the DC power source 3 side. The AC-DC converter 1 includes: a current source active rectifier 17 with a power factor improvement function, and the DC-DC converter 2 includes a chopper circuit, which includes a reactor configured on the AC-DC converter 1 side, and a half-bridge circuit configured on the DC power source 3 side. Figure 2 In the first example shown, the current source active rectifier 17 is formed by a full bridge circuit including four switching elements 1S.

[0047] In the DC-DC converter 2, the reactor is formed using a plurality of coils 7, and the half-bridge circuit is formed using the inverter 5. Specifically, the multi-phase coils 7 connected in parallel appear to be one coil, and together with the inductor Le described later, form a reactor. In addition, the arms of each phase connected in parallel of the inverter 5 appear to be one phase arm, forming a half-bridge circuit. The neutral point 7N of the coil 7 is connected to the AC-DC converter 1 via the inductor Le. In addition, the inductor Le may not be provided, and the neutral point 7N may be connected to the AC-DC converter 1. The end on the side opposite to the neutral point 7N of each phase coil 7 is connected to the midpoint of each phase arm of the inverter 5 (the connection point between the upper side switching element and the lower side switching element of each arm). In addition, the reactor may also be called a choke coil.

[0048] In addition, the current source active rectifier 17 of the AC-DC converter 1 is composed of a bidirectional switching element. Specifically, one arm of the full-bridge circuit constituting the current source active rectifier 17 is composed of two bidirectional switching elements connected in series from the positive side of the DC to the negative side. The bidirectional switching element is an element that can flow current in both directions, and has the same withstand voltage for positive and negative polarity voltages relative to the element. Therefore, it is easy to construct an AC-DC converter 1 with a current-controlled active rectification circuit. In a voltage-controlled AC-DC converter, a large-capacity capacitor is required, but by setting it as a current-controlled AC-DC converter, a large-capacity capacitor is not required, which can reduce component costs and suppress large-scale equipment.

[0049] In addition, the current source active rectifier 17 is as follows Fig.16 As shown in the example of the first charging device 10X, it is not a unidirectional current source active rectifier but a bidirectional current source active rectifier. Therefore, it is not only possible to perform power conversion from AC to DC, but also from DC to AC. Therefore, the DC power supply 3 of an electric vehicle or a hybrid vehicle can also be used as an emergency AC power supply.

[0050] In addition, Figure 2 The example in the figure shows a form in which a filter 1f (inductor / capacitor / filter) composed of a filter inductor Lf and a filter capacitor Cf is arranged between the external AC power source 4 and the current source active rectifier 17, similarly to the first charging device 10X. In addition, the example shows a form in which a differential mode inductor Lg is arranged between the filter 1f and the external AC power source 4. In addition, a freewheeling diode (DC link freewheeling diode Dfw) is arranged between the AC-DC converter 1 and the DC-DC converter 2, with the direction from the negative electrode to the positive electrode in the first DC power being set as the forward direction.

[0051] In a structure where the external AC power source 4 and the DC power source 3 are not electrically independent of each other, in the event of a short-circuit fault of the external AC power source 4, there is a concern that a large short-circuit current will flow to the DC power source 3 and the vehicle-mounted device connected to the DC power source 3. However, in this embodiment, since a DC link freewheeling diode Dfw is provided, even if a short circuit occurs between the positive and negative poles at the output end of the AC-DC converter 1 (or the input end of the DC-DC converter 2), the current flowing from the positive pole to the negative pole can be cut off by the DC link freewheeling diode Dfw. Therefore, even if an insulating circuit using a transformer is not provided in the vehicle-mounted charging device 10, for example, a short-circuit fault of the external AC power source 4 as described above can be prevented. That is, the increase in the circuit scale of the vehicle-mounted charging device 10 can be suppressed.

[0052] The vehicle-mounted charging device 10 of the present embodiment, which is configured in a manner capable of bidirectional power conversion from AC to DC (second DC power) and from DC (second DC power) to AC, can be configured as follows. When the vehicle-mounted charging device 10 charges the DC power supply 3 through the external AC power supply 4, the AC / DC converter 1 functions as a single power factor AC / DC buck converter (AC / DC Buck Converter UPF (Unity Power Factor)), and the DC / DC converter 2 functions as a DC / DC boost converter (DC / DC Boost Converter). When the vehicle-mounted charging device 10 functions as an emergency AC power supply that outputs AC power through the power stored in the DC power supply 3, the DC / DC converter 2 functions as a DC / DC buck converter (DC / DC Buck Converter), and the AC / DC converter 1 functions as a single power factor DC / AC boost converter (DC / AC Boost Converter UPF).

[0053] In addition, in the present embodiment, the vehicle-mounted charging device 10 can also function the DC / DC converter 2 as a DC / DC buck converter (DC / DC Buck Converter) when charging the DC power supply 3 through the external AC power supply 4. In other words, the vehicle-mounted charging device 10 as a whole can have the function of an AC / DC buck converter (AC / DC Buck Converter) and the function of an AC / DC boost converter (AC / DC Boost Converter) as a function of power conversion from AC power to the second DC power (battery power).

[0054] In order to supply power to the rotating motor 70 driving the wheels, the DC power supply 3 mounted on the vehicle is often a power supply with different rated voltages. Even for the same vehicle model, the rated voltage of the DC power supply 3 may be different due to the level. For example, in the upper level, in order to obtain a higher output, a DC power supply 3 with a higher rated voltage may be mounted. In the case where the voltage is higher than the voltage obtained by converting the AC to DC from the general industrial power supply, that is, the external AC power supply 4, it is necessary to boost the voltage in the DC to DC converter 2. If the vehicle-mounted charging device 10 with different structures is mounted according to the vehicle, economies of scale cannot be obtained, and the cost reduction of the vehicle-mounted charging device 10 is limited. However, by configuring the DC to DC converter 2 with a step-up and step-down function, the same hardware can be used, and the same vehicle-mounted charging device 10 can be configured in multiple levels and multiple vehicle models by changing the control form (for example, software such as a program). For example, in the case where the rated voltage of the DC power supply 3 is 400 volts and in the case where it is 800 volts, the vehicle-mounted charging device 10 with the same hardware structure can be used.

[0055] As described above, in the present embodiment, the reactor of the DC-DC converter 2 is formed by a series circuit of a plurality of coils 7 connected in parallel and an inductor Le (additional inductor or external inductor) connected to the neutral point 7N of the plurality of coils 7 .

[0056] When the DC-DC converter 2 functions as a boost converter, the reactor stores energy. The coil 7 of the rotary electric machine 70 is designed to have a high power density, so the inductance as a reactor is often small. By connecting the inductor Le in series with the coil 7, the inductance of the inductor Le can also be used to set a sufficient inductance for the reactor, and the function as a boost converter can be appropriately ensured.

[0057] like Figure 2 As shown, the vehicle-mounted charging device 10 includes a main contactor 11, a function switching contactor 12, and a grid contactor 13. The above-mentioned contactors are composed of relays and the like, and are controlled by the control device 80, or by the control device 80 and the vehicle control device 90. Figure 1 As described above, the control device 80 is included in the driving control system of the rotating electric machine, and the driving control of the rotating electric machine 70 and the charging control of the DC power supply 3 can also share the control device 80 .

[0058] Reference Figure 1As described above, the main contactor 11 is configured to be able to disconnect or connect the electrical connection between the DC power supply 3 and the inverter 5. When the inverter 5 functions as the vehicle drive device 9 or when the inverter 5 functions as the vehicle-mounted charging device 10, the main contactor 11 is closed. When the DC power supply 3 is not charged and the vehicle is parked, the electrical connection between the DC power supply 3 and the inverter 5 can be disconnected by setting the main contactor 11 to an open state. The grid contactor 13 is configured to be able to disconnect or connect the electrical connection between the external AC power supply 4 and the AC-DC converter 1. The function switching contactor 12 can disconnect or connect the electrical connection between the AC-DC converter 1 and the reactor (here, the inductor Le). In other words, the reactor is arranged between the AC-DC converter 1 and the inverter 5 via the function switching contactor 12 that disconnects or connects the electrical connection. The function switching contactor 12 is closed when the inverter 5 functions as the vehicle-mounted charging device 10, and the AC-DC converter 1 is electrically connected to the reactor. When the coil 7 and the inverter 5 function as the vehicle drive device 9 , the function switching contactor 12 is opened.

[0059] In this way, only by changing the connection form for the inverter 5 and the coil 7, a circuit capable of switching the function of driving and controlling the rotating motor 70 and the function of charging the DC power supply 3 through the external AC power supply 4 can be realized. That is, the on-board charging device 10 can be constituted with a simple structure. As described above, the on-board charging device 10 of the present embodiment is a bidirectional power conversion device that can not only convert power from AC power to the second DC power but also convert power from the second DC power to AC power. By converting power from the second DC power to AC power, the function of outputting AC power from the DC power supply 3 can be realized. In the case of realizing the function of outputting AC power from the DC power supply 3, the main contactor 11 and the function switching contactor 12 are closed. The grid contactor 13 is opened or closed according to the form of the output destination of the AC current.

[0060] Hereinafter, a case where the on-vehicle charger 10 as a whole functions as an AC / DC Buck Converter and a case where the on-vehicle charger 10 functions as an AC / DC Boost Converter will be described by exemplifying each current loop. Figure 3 to Figure 6 The figure shows a current loop when the vehicle-mounted charger 10 functions as an AC / DC Buck Converter. Figure 7 to Figure 10 The current loop when the vehicle-mounted charger 10 functions as an AC / DC boost converter is shown.

[0061] In the description of the current loop, the control states of the switch elements of the full-bridge circuit of the current source active rectifier 17 of the AC-DC converter 1 and the half-bridge circuit implemented by the inverter 5 of the DC-DC converter 2 are also shown. The full-bridge circuit of the current source active rectifier 17 has a first arm in which the first switch S1 and the second switch S2 are connected in series in the order described, and a second arm in which the third switch S3 and the fourth switch S4 are connected in series in the order described, from the positive side of the DC to the negative side. The half-bridge circuit implemented by the inverter 5 is composed of a fifth switch S5 and a sixth switch S6 connected in series in the order described, from the positive side of the DC to the negative side.

[0062] Table 1 below shows Figures 3 to 10 The function of the on-board charging device 10 shown, the direction of the current loop, the action stage, and the control state of the switch element (on state / off state). "Fig." in the table shows the number of the figure marked in this specification, and "Function" shows whether the function of the on-board charging device 10 is an AC / DC boost converter (AC / DCBoost Converter) or an AC / DC buck converter (AC / DC Buck Converter). In addition, "Loop" shows whether the current loop is a positive current loop (Posi.) or a negative current loop (Nega.). "Phase" shows the function of the current loop, "C Charging" shows the state of charging the output capacitor, "LCharging" shows the state of charging the reactor (inductor Le, coil 7), and "Free Wheeling" shows the state of current circulation. "S1" to "S6" show the above-mentioned first switch S1 to the sixth switch S6, "ON" shows the state of controlling the switch to the on state, and "OFF" shows the state of controlling the switch to the off state.

[0063] [Table 1]

[0064]

[0065] Figure 3The positive current loop when charging the output capacitor Cs (DC link capacitor 6) connected in parallel with the DC power supply 3 in the on-vehicle charging device 10 functioning as an AC-DC step-down converter when charging the DC power supply 3 is shown. The current from the external AC power supply 4 (for convenience, the positive side of the external AC power supply 4) forms a current loop that passes through the input inductor Li, the first switch S1 in the on state, the reactor (inductor Le, coil 7), the flyback diode connected in reverse parallel to the fifth switch S5 in the off state, the output capacitor Cs, and the fourth switch S4 in the on state, and returns to the external AC power supply 4 (for convenience, the negative side of the external AC power supply 4). The output capacitor Cs is charged through this current loop. In addition, according to the structure of the fifth switch S5, the flyback diode may not be provided, and the current flowing in the flyback diode passes through the body diode of the switching element and the reverse conduction function of the switching element. The same is true in the following description.

[0066] Figure 4 The positive current loop of the on-vehicle charging device 10 that functions as an AC-DC step-down converter is shown. In this stage, the first switch S1 and the second switch S2 are in the off state, and the connection between the AC-DC converter 1 and the DC-DC converter 2 is cut off. The current returning from the output capacitor Cs to the external AC power supply 4 side passes through the DC link flyback diode Dfw and returns to the DC-DC converter 2. That is, the current flows in the forward path such as the reactor (inductor Le, coil 7), the flyback diode connected in reverse parallel to the fifth switch S5 in the off state, the output capacitor Cs, the DC link flyback diode Dfw, and the reactor, and circulates in the DC-DC converter 2.

[0067] Figure 5 The negative current loop is shown when the output capacitor Cs connected in parallel with the DC power supply 3 is charged in the vehicle-mounted charging device 10 functioning as an AC-DC step-down converter when charging the DC power supply 3. The current from the external AC power supply 4 (for convenience, the negative side of the external AC power supply 4) forms a current loop that passes through the third switch S3 in the on state, the reactor (inductor Le, coil 7), the freewheeling diode connected in anti-parallel to the fifth switch S5 in the off state, the output capacitor Cs, the second switch S2 in the on state, and the input inductor Li, and returns to the external AC power supply 4 (for convenience, the positive side of the external AC power supply 4). The output capacitor Cs is charged through this current loop.

[0068] Figure 6The negative current loop of the on-vehicle charging device 10 that functions as an AC-DC step-down converter is shown. In this stage, the first switch S1 and the second switch S2 are in the off state, and the connection between the AC-DC converter 1 and the DC-DC converter 2 is cut off. The current returning from the output capacitor Cs to the external AC power supply 4 side passes through the DC link flyback diode Dfw and returns to the DC-DC converter 2. That is, the current flows in the forward path of the reactor (inductor Le, coil 7), the flyback diode connected in reverse parallel to the fifth switch S5 in the off state, the output capacitor Cs, the DC link flyback diode Dfw, and the reactor, and circulates in the DC-DC converter 2.

[0069] Figure 7 The positive current loop when charging the reactor in the vehicle-mounted charging device 10 functioning as an AC-DC boost converter when charging the DC power supply 3 is shown. The current from the external AC power supply 4 (for convenience, the positive side of the external AC power supply 4) forms a current loop that passes through the input inductor Li, the first switch S1 in the on state, the reactor (inductor Le, coil 7), the sixth switch S6 in the on state, the fourth switch S4 in the on state, and returns to the external AC power supply 4 (for convenience, the negative side of the external AC power supply 4). The reactor is charged through this current loop.

[0070] Figure 8 The positive current loop of the on-vehicle charging device 10 functioning as an AC-DC boost converter is shown. In this stage, the first switch S1 and the second switch S2 are in the off state, and the connection between the AC-DC converter 1 and the DC-DC converter 2 is cut off. The fifth switch S5 and the sixth switch S6 are both controlled to be in the off state, and the current flowing in the reactor (inductor Le, coil 7) flows in the forward path of the freewheeling diode, output capacitor Cs, DC link freewheeling diode Dfw, and reactor connected in anti-parallel with the fifth switch S5 in the off state, and circulates in the DC-DC converter 2. The energy stored in the reactor is supplied to the output capacitor Cs.

[0071] Fig. 9 The negative current loop when the DC power source 3 is charged to the reactor in the vehicle-mounted charging device 10 functioning as an AC-DC boost converter when charging the DC power source 3 is shown. The current from the external AC power source 4 (for convenience, the negative side of the external AC power source 4) forms a current loop that passes through the third switch S3 in the on state, the reactor (inductor Le, coil 7), the sixth switch S6 in the on state, the second switch S2 in the on state, the input inductor Li, and returns to the external AC power source 4 (for convenience, the positive side of the external AC power source 4). The reactor is charged through this current loop.

[0072] Fig.10 The negative current loop of the on-vehicle charging device 10 that functions as an AC-DC boost converter is shown. In this stage, the first switch S1 and the second switch S2 are in the off state, and the connection between the AC-DC converter 1 and the DC-DC converter 2 is cut off. The fifth switch S5 and the sixth switch S6 are both controlled to be in the off state, and the current flowing in the reactor (inductor Le, coil 7) flows in the forward path of the freewheeling diode, output capacitor Cs, DC link freewheeling diode Dfw, and reactor connected in anti-parallel with the fifth switch S5 in the off state, and circulates in the DC-DC converter 2. The energy stored in the reactor is supplied to the output capacitor Cs.

[0073] In this way, the vehicle-mounted charging device 10 has a step-down function and a step-up function from the AC power to the second DC power (battery power), so that, for example, when the rated voltage of the DC power supply 3 is 400 volts or 800 volts, the vehicle-mounted charging device 10 with the same hardware structure can be used.

[0074] Fig.11 The circuit block diagram of shows a second example of the vehicle-mounted charging device 10. In the first example, the external AC power source 4 is a single-phase AC power source, whereas in the second example, the external AC power source 4 is a multi-phase AC power source. Here, the external AC power source 4 is illustrated as a three-phase AC power source connected at a neutral point 4N and having different phases of 2π / 3. Corresponding to the three-phase AC power source, the grid contactor 13 is also configured with three contacts.

[0075] The AC-DC converter 1 of the second example is configured to convert power from three-phase AC to DC, similar to the inverter 5, and includes a three-phase bridge circuit 18 having three arms corresponding to each of the three phases. The three-phase bridge circuit 18 also includes a current source active rectifier having a power factor improvement function. The other configurations are the same as those described in the first example, so detailed descriptions are omitted.

[0076] Fig.12The circuit block diagram shows a third example of the on-board charging device 10. In the first example, the external AC power supply 4 is a single-phase AC power supply, and in the second example, the external AC power supply 4 is a multi-phase AC power supply. In contrast, in the third example, it is configured to be able to connect both single-phase and multi-phase (here, three-phase) external AC power supplies 4. That is, the on-board charging device 10 of the third example can selectively connect an external AC power supply 4 that supplies a single-phase AC, and an external AC power supply 4 that supplies a multi-phase AC. The grid contactor 13 has four contacts, namely, a U-phase contact 13u, a V-phase contact 13v, and a W-phase contact 13w for connecting a three-phase external AC power supply 4; and a single-phase contact 13a for connecting a single-phase external AC power supply 4. In addition, the AC-DC converter 1 has: a three-phase bridge circuit 18 having three arms corresponding to each of the three phases, and a single-phase arm 19 (half-bridge circuit).

[0077] When the external AC power source 4 is a three-phase AC power source as in the second example, among the four contacts of the grid contactor 13, the U-phase contact 13u, the V-phase contact 13v, and the W-phase contact 13w are closed, and the single-phase contact 13a is opened. During the AC-DC conversion, the three-phase bridge circuit 18 is switched, and the single-phase arm 19 is always maintained in the off state without being switched. That is, in this case, the vehicle-mounted charging device 10 of the third example is the same as the vehicle-mounted charging device 10 of the second example.

[0078] When the external AC power source 4 is a single-phase AC power source as in the first example, one of the three-phase AC power sources corresponds to the single-phase AC power source. Fig.12 , the U-phase AC power supply 4u marked with the figure mark is configured as a single-phase AC power supply. Among the four contacts of the grid contactor 13, the single-phase contact 13a and the U-phase contact 13u are closed, and the V-phase contact 13v and the W-phase contact 13w are opened. In the three-phase bridge circuit 18, only the U-phase arm 18u is controlled by the switch, and the other two-phase arms are always maintained in the off state without being controlled by the switch. During AC-DC conversion, the single-phase arm 19 and the U-phase arm 18u are controlled by the switch. That is, in this case, the vehicle-mounted charging device 10 of the third example is the same as the vehicle-mounted charging device 10 of the first example.

[0079] In this way, the on-board charging device 10 of the third example can selectively implement the on-board charging device 10 of the first example and the on-board charging device 10 of the second example. Therefore, the on-board charging device 10 of the same specification can be applied to multiple models, and cost reduction can be easily achieved through economies of scale in production quantity. In addition, when the external AC power supply 4 that can be connected is limited to a single phase, the grid contactor 13 can only use the single-phase contact 13a as in the first example. In addition, with respect to the three-phase bridge circuit 18 of the AC-DC converter 1, by using a common circuit substrate and not installing a switching element, it is also possible to at least reduce the component cost. Therefore, for example, even if only a single-phase AC power supply is assumed as the external AC power supply 4 for charging at home, the cost increase of the on-board charging device 10 can be suppressed, and the on-board charging device 10 of the third example can be realized at a cost substantially the same as the on-board charging device 10 of the first example through the above-mentioned economies of scale.

[0080] Fig.13 An example of a current loop when the vehicle-mounted charger 10 of the third example is supplied with electric power from the three-phase external AC power supply 4 is shown. Fig.13 The current loop of phase Q is shown. Positive current flows in phase U, and negative current flows in phase V and phase W. The current path, especially the current path flowing in the DC-DC converter 2, is similar to that in reference 1. Figure 3 The described forms are the same, so detailed description is omitted.

[0081] Fig.14 FIG. 2 shows an example of a current circulation loop in the vehicle-mounted charging device 10 of the third example. The current path, especially the current path flowing in the DC-DC converter 2, is similar to the reference path. Figure 4 The described forms are the same, so detailed description is omitted.

[0082] Fig.15 FIG. 1 shows an example of a positive current loop when the vehicle-mounted charger 10 of the third example is supplied with power from the single-phase external AC power supply 4. Figure 3 The situation described is the same, so the detailed description is omitted. In addition, the circulation circuit is also the same as the reference Figure 4 The situations described are the same, so illustrations and detailed descriptions are omitted.

Claims

1. A vehicle-mounted charging device, which is mounted on a vehicle and includes: a rotating electric machine having multi-phase coils connected to each other at a neutral point and serving as a driving force source for wheels, an inverter for converting electric power between direct current and multi-phase alternating current, and a direct current power source connected to the rotating electric machine via the inverter, and the direct current power source is charged by electric power supplied from an external alternating current power source, characterized in that: have: an AC-DC converter that converts power between the AC power on the external AC power source side and the first DC power; and a DC-DC converter for converting power between the first DC power and the second DC power on the DC power supply side, The AC-DC converter has: a current source active rectifier with a power factor improvement function, The DC-DC converter includes a chopper circuit including: a reactor disposed on the AC-DC converter side, and a half-bridge circuit disposed on the DC power supply side. The reactor is formed by using a plurality of the coils. The above-mentioned half-bridge circuit is constructed using the above-mentioned inverter. The current source active rectifier is constructed using a bidirectional switching element.

2. The vehicle-mounted charging device according to claim 1, characterized in that: The reactor is formed of a series circuit of the plurality of coils connected in parallel and an inductor connected to the neutral points of the plurality of coils.

3. The vehicle-mounted charging device according to claim 1, characterized in that: The reactor is disposed between the AC / DC converter and the inverter via a contactor that disconnects or connects an electrical connection.

4. The vehicle-mounted charging device according to any one of claims 1 to 3, characterized in that: The external AC power source that supplies a single-phase AC and the external AC power source that supplies a multi-phase AC can be selectively connected.

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