On-vehicle charger

Abstract

To configure an on-vehicle charger that charges an on-vehicle DC power source with power from an external AC power source, while ensuring safety and controlling system costs.SOLUTION: A first circuit 1 which converts AC power into first DC power, includes a full bridge circuit 111 configured using a first switching element 11S, and is switched-controlled at a first switching frequency corresponding to a commercial frequency of an external AC power source 4. A second circuit 2 which converts the first DC power into second DC power on a side of a first DC power source 3 and third DC power on a side of a second DC power source 30, includes a triple active bridge circuit equipped with a transformer T, and a primary side bridge circuit 211, a secondary side first bridge circuit 212, and a secondary side second bridge circuit 213, which are configured using second switching elements 21S, 22S, and 23S, are switched-controlled at a second switching frequency of 10 kHz or more which is higher than the commercial frequency.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an on-board charging device. [Background technology]

[0002] JP2022-503713A discloses an onboard charging device (onboard charger) that charges a DC power source mounted on a vehicle equipped with a rotating electric machine as a driving force source for wheels such as an electric vehicle or a hybrid vehicle while the vehicle is mounted on the vehicle. FIG. 1 of this document shows a schematic block diagram of an onboard charging device that receives power from an external AC power source (110) and charges an onboard DC power source (140). This onboard charging device includes an AC-DC converter (120) that converts AC power supplied from the external AC power source into DC power, and a DC-DC converter (130) that transforms the converted DC power while reducing pulsating components contained in the converted DC power and supplies it to the DC power source.

[0003] FIG. 7 illustrates one form of such an on-board charging device (on-board charging device (10X) of a first conventional example). The AC-DC converter (1) can be configured to include an input inductor (Li) and a full bridge circuit (111). The DC-DC converter (2) can be configured as a dual active bridge (DAB) circuit including a transformer (T), a full bridge circuit (211) arranged on the primary side of the transformer (T), and a full bridge circuit (212) arranged on the secondary side of the transformer (T). The AC-DC converter (1) including the full bridge circuit (111) also functions as a power factor correction (PFC) circuit that improves the power factor of the DC power converted from the AC power. The full bridge circuit (111) is also switched and controlled to suppress pulsation of the second harmonic of the frequency of the AC power. The DC-DC converter (2) uses a dual active bridge circuit to further reduce the pulsating component of the DC power and provides the charging current to the DC power source (3).

[0004] In addition, electric vehicles, which have become increasingly popular in recent years, may be equipped with motors that require a relatively high output (work load) in addition to the rotating electric machine (travel motor) that serves as the driving force source for the wheels. For example, there are motors that drive devices (compressors, etc.) that constitute an air conditioner that cools and heats the vehicle interior, and motors that drive pumps that circulate fluids (e.g., oil) for lubricating and cooling the wheel drive devices (travel motor, gear mechanism, etc.). In addition to a DC power source (first DC power source) connected to the travel motor, a second DC power source may be provided to supply power to these motors. As shown in FIG. 8 as an example of a second conventional on-board charging device (10Y), it is preferable that not only the first DC power source (3) but also the second DC power source (30) can be charged from an external AC power source (4). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2022-503713 Summary of the Invention [Problem to be solved by the invention]

[0006] The vehicle-mounted charging device illustrated in FIG. 7 and FIG. 8 includes a plurality of bridge circuits, and many switching elements are used in the vehicle-mounted charging device as a whole. These switching elements are switched by, for example, pulse width modulation control at a frequency at least several tens of times higher than the frequency of the external AC power source in order to reduce the pulsating component in the DC power for charging the DC power source. For this reason, the switching loss tends to be large, and the system efficiency of the vehicle-mounted charging device may decrease and the system cost may increase. In addition, in recent years, the performance of rechargeable secondary batteries has been significantly improved, and it may become possible to tolerate a charging current having a pulsation with a larger amplitude than before during charging. Therefore, it may be possible to reduce the degree of reduction of the pulsating component generated during power conversion from AC to DC compared to before. However, from the viewpoint of maintaining high safety for vehicle occupants as before, it is preferable that an insulating circuit exists between the external AC power source side and the DC power source side as before.

[0007] In view of the above background, it is desirable to configure an on-board charging device that charges an on-board DC power supply with power from an external AC power supply in a manner that ensures safety and reduces system costs. [Means for solving the problem]

[0008] In view of the above, an on-vehicle charging device is an on-vehicle charging device that charges a first DC power source and a second DC power source electrically insulated from the first DC power source with power supplied from an external AC power source, the on-vehicle charging device comprising: a first circuit that converts AC power on the external AC power source side into first DC power; a second circuit that converts the first DC power into second DC power on the first DC power source side and also converts the first DC power into third DC power on the second DC power source side; and a DC link capacitor that is disposed between the first circuit and the second circuit and smoothes a first DC voltage in the first DC power, the first circuit comprising a full bridge circuit formed using a first switching element, and an input inductor connected between a midpoint of one leg of the full bridge circuit and the external AC power source, the second circuit comprising a primary side coil, a secondary side first coil, and a second coil. a triple active bridge circuit having at least a power factor correction function of the AC power, a function of generating a first battery voltage to be applied to the first DC power source, and a function of generating a second battery voltage to be applied to the second DC power source, the primary side bridge circuit, the secondary side first bridge circuit, and the secondary side second bridge circuit being configured using second switching elements different from the first switching elements, the first switching elements being switched-controlled at a first switching frequency corresponding to a commercial frequency which is a frequency of the AC power, and the second switching elements being switched-controlled at a second switching frequency which is 10 kHz or more higher than the commercial frequency.

[0009] According to this configuration, in the first circuit, which is switching-controlled at a first switching frequency corresponding to the commercial frequency, the first DC power can be obtained, although a large pulsating component remains in the DC power converted from the AC power. Since the first switching element is switching-controlled at the first switching frequency, the switching loss of the first circuit can be easily kept low. In the second circuit, which includes a triple active bridge circuit, which is switching-controlled at a second switching frequency that is about 1000 times faster than the first switching frequency, the high-speed switching can adjust the current phase and voltage phase in the first DC power in which a large AC component remains, thereby improving the power factor, and further, the amplitude of the pulsating component superimposed on the first DC power can be easily attenuated, and appropriate second DC power and third DC power can be obtained. In addition, since the first DC power output from the first circuit does not require a large reduction in the pulsating component, the capacity of the DC link capacitor arranged between the first circuit and the second circuit can be easily kept small. Therefore, the size of the DC link capacitor can be easily kept small, and the size of the on-board charging device can also be easily kept small. In addition, the triple active bridge circuit includes a transformer, and the circuit on the external AC power supply side is insulated from the circuits on the first DC power supply and second DC power supply sides, which facilitates improving safety. Thus, according to this configuration, an on-board charging device that charges an on-board DC power supply with power from an external AC power supply can be configured with reduced system costs while ensuring safety.

[0010] Further features and advantages of the on-board charging device will become apparent from the following description of exemplary and non-limiting embodiments which are given with reference to the drawings. [Brief description of the drawings]

[0011] [Figure 1] A block diagram showing a schematic configuration of an in-vehicle system including a drive control system for a rotating electric machine. [Diagram 2] 1 is a schematic circuit block diagram showing a first example of an in-vehicle charging device; [Diagram 3] Schematic circuit block diagram showing a second example of an in-vehicle charging device [Figure 4] Schematic circuit block diagram showing a third example of an in-vehicle charging device [Diagram 5] Schematic circuit block diagram showing a fourth example of an in-vehicle charging device [Figure 6] Schematic circuit block diagram showing a fifth example of an in-vehicle charging device [Figure 7] A circuit block diagram showing the configuration of a conventional single-port in-vehicle charging device. [Figure 8] A circuit block diagram showing the configuration of a conventional dual-port in-vehicle charging device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the vehicle-mounted charging device will be described with reference to the drawings. The circuit block diagram of FIG. 1 shows a schematic diagram of an in-vehicle system including a drive control system for a rotating electric machine 70. The rotating electric machine 70 is a traction rotating electric machine that serves as a driving force source for the wheels of a vehicle on which the vehicle-mounted charging device 10 is mounted. That is, the rotating electric machine 70 is a driving force source for the wheels of a hybrid vehicle, an electric vehicle, or the like. Note that the vehicle may also have other driving force sources such as an internal combustion engine (not shown) in addition to the rotating electric machine 70 as a driving force source for the wheels. The rotating electric machine 70 is a rotating electric machine that includes a multi-phase stator coil 7 that is connected to each other at a neutral point 7N. The rotating electric machine 70 is connected to a first DC power source 3 via an inverter 5 that converts power between DC and multi-phase AC. The vehicle-mounted charging device 10 charges the first DC power source 3 with power supplied from an external AC power source 4 (see FIG. 2, etc.).

[0013] As shown in FIG. 1, the vehicle includes a rotating electric machine control device 80 that controls a rotating electric machine 70, and the rotating electric machine control device 80 drives and controls the rotating electric machine 70 by performing current feedback control. The rotating electric machine 70 is an interior permanent magnet type rotating electric machine (IPMSM: Interior Permanent Magnet Synchronous Motor) having a stator in which a stator coil 7 of multiple phases (N phases, where N is any natural number; in this embodiment, a three-phase form with N=3 is illustrated) is arranged in a stator core, and a rotor in which a permanent magnet is arranged in a rotor core. Such a configuration is well known, and in this embodiment, the stator core, stator, rotor core, rotor, permanent magnets, etc. are not illustrated. In this embodiment, a Y-type (star type) form in which the three-phase stator coils 7 are short-circuited at a neutral point 7N is illustrated. However, the rotating electric machine 70 may be, for example, provided with two sets of three-phase stator coils and driven by six-phase AC. The rotating electric machine 70 can function as both an electric motor and a generator. When the rotating electric machine 70 functions as an electric motor, the rotating electric machine 70 is in a power running state, and when the rotating electric machine 70 functions as a generator, the rotating electric machine 70 is in a regenerative state.

[0014] As shown in FIG. 1, the rotating electric machine 70 and the first DC power source 3 are connected via an inverter 5. The inverter 5 converts power between multiple-phase AC and DC. In this embodiment, the inverter 5 includes a U-phase leg, a V-phase leg, and a W-phase leg as multiple-phase legs (which may also be called arms). Each leg is formed by connecting in series an upper-stage switching element arranged on the positive side and a lower-stage switching element arranged on the negative side. The midpoint of each leg, that is, the connection point between the upper-stage switching element and the lower-stage switching element, is connected to the stator coil 7. Specifically, the midpoint of the U-phase leg is connected to the U-phase coil 7u, the midpoint of the V-phase leg is connected to the V-phase coil 7v, and the midpoint of the W-phase leg is connected to the W-phase coil 7w.

[0015] A decoupling capacitor 6 that smoothes the voltage between the positive and negative electrodes is provided on the DC side of the inverter 5. That is, the decoupling capacitor 6 is connected to the first DC power supply 3 in parallel.

[0016] The first DC power source 3 is, for example, a rechargeable secondary battery (battery) such as a lithium ion battery, an electric double layer capacitor, or the like. When the rotating electric machine 70 is the driving force source of the vehicle as in this embodiment, the first DC power source 3 is a high-voltage, large-capacity DC power source, and the rated power source voltage is, for example, 200 to 800 [V]. In many cases, the first DC power source 3 is configured so that the electrical connection to the inverter 5 can be made and broken by operating the main switch (ignition switch) of the vehicle, or the like. For example, the first DC power source 3 is connected to the inverter 5 via a main contactor 11 configured by a relay or the like. The relay may be a mechanical relay or a semiconductor relay (solid state relay). The same applies to other contactors below.

[0017] 1, the vehicle is equipped with a first DC power supply 3 connected to a rotating electric machine 70, and also with a second DC power supply 30 having a lower rated voltage than the first DC power supply 3. The rated power supply voltage of the second DC power supply 30 is approximately 12 to 400 volts.

[0018] For example, when the rated voltage of the first DC power supply 3 is a high voltage of about 800 volts, it is preferable that the rated voltage of the second DC power supply 30 is 200 to 400 volts. In this case, it is preferable that, for example, an air conditioner compressor or an electric oil pump is driven by power supplied from the second DC power supply. Note that the vehicle also requires a DC power supply with an even lower rated voltage, for example, about 12 to 24 volts. Therefore, when the rated voltage of the second DC power supply 30 exceeds 24 volts, another DC power supply may be provided.

[0019] Furthermore, for example, when the rated voltage of the first DC power supply 3 is about 200 to 400 volts, it is preferable that the rated voltage of the second DC power supply 30 is 12 to 24 volts. In this case, the second DC power supply 30 supplies power to, for example, indicators of the vehicle, such as the instrument panel, lighting devices, audio systems, and electronic circuits such as the rotating electric machine control device 80 and the vehicle control device 90. When the rated voltage of the first DC power supply 3 is about 200 to 400 volts, it is preferable that the compressor and the electric oil pump of the air conditioner are supplied with power from the first DC power supply 3. Note that, when the rated voltage of the second DC power supply 30 is 12 to 24 volts, it may be, for example, a lead storage battery, as in a conventional vehicle in which an internal combustion engine is used as a driving force source for the wheels.

[0020] As shown in Fig. 1, the second DC power source 30 can be charged by the power of the first DC power source 3 via a voltage conversion circuit 33 configured with a DC-DC converter or the like as a core. On the other hand, as described later with reference to Fig. 2 and the like, the second DC power source 30 can also be charged by AC power supplied from an external AC power source 4 via the vehicle-mounted charging device 10 together with the first DC power source 3. That is, the vehicle-mounted charging device 10 is a device that charges the first DC power source 3 and the second DC power source 30, which is electrically insulated from the first DC power source 3, by power supplied from the external AC power source 4. As described later, the vehicle-mounted charging device 10 is configured to have a circuit equipped with a switching element, and the switching element is switched and controlled by the charging control device 100.

[0021] Although not shown in the drawings, for example, when the first DC power source 3 and the second DC power source 30 are lithium ion batteries, a battery management system (BMS) is often provided. A secondary battery such as a lithium ion battery is composed of a plurality of cells (battery cells). The battery management system is a battery management control system that performs the following: (1) prevention of overcharging and overdischarging of cells, (2) prevention of overcurrent flowing through cells, (3) cell temperature management, (4) calculation of the state of charge (SOC), (5) equalization of cell voltages, etc. The charging control device 100 charges the first DC power source 3 and the second DC power source 30 by controlling the switching of switching elements of the in-vehicle charging device 10 based on information from the battery management system.

[0022] As shown in FIG. 1, the inverter 5 is configured to have a plurality of switching elements. FIG. 1 illustrates an example in which a field effect transistor (FET) is used as the switching element, but an insulated gate bipolar transistor (IGBT) may be used. In FIG. 1 and other figures, a freewheel diode is connected in parallel to each switching element with a forward direction being a direction from the negative electrode to the positive electrode (direction from the lower stage to the upper stage). Of course, when a body diode is used or when reverse conduction is used in a transistor of a wide band gap semiconductor made of enhancement mode gallium nitride (E-GaN), such a freewheel diode may not be provided. This is true not only for the inverter 5 but also for the freewheel diode in the vehicle-mounted charging device 10.

[0023] As shown in FIG. 1, the inverter 5 is controlled by a rotating electric machine control device 80. The rotating electric machine control device 80 is constructed with a logic circuit such as a microcomputer as a core component. For example, the rotating electric machine control device 80 performs current feedback control based on a target torque (torque command) of the rotating electric machine 70 provided as a request signal from another control device such as a vehicle control device 90, which is one of the higher-level control devices, to drive the rotating electric machine 70 via the inverter 5. The operating voltage of a logic circuit element such as a microcomputer is generally 5 volts or less. In this embodiment, although not shown for simplification, a control signal generated by the logic circuit element is transmitted to the inverter 5 via a drive circuit. Alternatively, it may be considered that the rotating electric machine control device 80 includes a drive circuit.

[0024] The actual current flowing through the stator coil 7 of each phase of the rotating electric machine 70 is detected by a current sensor 81, and the rotating electric machine control device 80 acquires the detection results. In addition, the magnetic pole position (electrical angle) of the rotor of the rotating electric machine 70 at each point in time 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, and the rotating electric machine control device 80 acquires the detection results. The rotating electric machine control device 80 executes current feedback control using the detection results of the current sensor 81 and the rotation sensor 82. The rotating electric machine control device 80 is configured to have various functional units for current feedback control, and each functional unit is realized by cooperation between hardware such as a microcomputer and software (program).

[0025] As described above, the rotating electric machine 70 connected to the first DC power source 3 via the inverter 5 functions as an electric motor by the power supplied from the first DC power source 3, and can also function as a generator to charge the first 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 or the like to cause the rotating electric machine 70 to generate electricity, but there are cases where the first DC power source 3 cannot be sufficiently charged because there are few opportunities for power generation. Also, in an electric vehicle equipped with only the rotating electric machine 70 as a driving force source, power generation is limited to mechanical energy from the wheels during inertial running, and the first DC power source 3 cannot be sufficiently charged in many cases. Also, in a hybrid vehicle, it may be more energy efficient to supply power from an external source rather than to have the rotating electric machine 70 generate power. For this reason, it is preferable that the first DC power source 3 be configured to be charged by an external power source when the first DC power source 3 is mounted on the vehicle. In many cases, the external power source is AC because it receives power from a commercial power source. The vehicle-mounted charging device 10 of this embodiment charges the first DC power source 3 with power supplied from an external AC power source 4. For this reason, the vehicle-mounted charging device 10 is configured to have a power conversion function from AC to DC.

[0026] The schematic circuit block diagram of FIG. 2 shows a first example of the vehicle-mounted charging device 10. The vehicle-mounted charging device 10 includes a first circuit 1 that converts AC power on the side of the external AC power source 4 into first DC power, a second circuit 2 that converts the first DC power into second DC power on the side of the first DC power source 3 and converts the first DC power into third DC power on the side of the second DC power source 30, and a DC link capacitor Cdc that is disposed between the first circuit 1 and the second circuit 2 and smoothes the first DC voltage in the first DC power. In this embodiment, the external AC power source 4 and the first circuit 1 are connected via a grid contactor 13 and an EMI filter FLT that reduces EMI (Electro Magnetic Interference) noise. In addition, the second circuit 2 and the first DC power source 3 are connected via a main contactor 11, and the second circuit 2 and the second DC power source 30 are connected via a second DC power source connection contactor 14.

[0027] The first circuit 1 is configured as an AC-DC converter having an active rectifier including a full bridge circuit 111 configured using a first switching element 11S and an input inductor Li connected between a midpoint of one leg of the full bridge circuit 111 and an external AC power source 4. The second circuit 2 is configured as a DC-DC converter having a triple active bridge circuit (TAB) including a transformer T having a primary coil T1, a secondary first coil T21, and a secondary second coil T22, a primary bridge circuit 211 connected to the primary coil T1, a secondary first bridge circuit 212 connected to the secondary first coil T21, and a secondary second bridge circuit 213 connected to the secondary second coil T22, and having at least a function of improving the power factor of AC power, a function of generating a first battery voltage to be applied to the first DC power source 3, and a function of generating a second battery voltage to be applied to the second DC power source 30. A first capacitor Cs1 is connected between the secondary side first bridge circuit 212 and the first DC power source 3, for smoothing the first battery voltage applied to charge the first DC power source 3. In addition, a second capacitor Cs2 is connected between the secondary side second bridge circuit 213 and the second DC power source 30, for smoothing the second battery voltage applied to charge the second DC power source 30.

[0028] The switching element 21S constituting the primary side bridge circuit 211, the switching element 22S constituting the secondary side first bridge circuit 212, and the switching element 23S constituting the secondary side second bridge circuit 213 are switching elements having the same physical properties and the same rated electrical specifications. These switching elements (21S, 22S, 23S) are collectively referred to as the second switching element. The second switching element is a switching element different from the first switching element 11S. The first switching element 11S is switching-controlled at a first switching frequency corresponding to the commercial frequency, which is the frequency of AC power. The second switching element is switching-controlled at a second switching frequency of 10 kHz or more, which is higher than the commercial frequency.

[0029] In one preferred embodiment, the first switching frequency is the same as the frequency of the AC power, that is, the commercial frequency of the external AC power source 4 (for example, 50 [Hz] or 60 [Hz]). The first switching frequency may be a natural number multiple of the commercial frequency of the external AC power source 4, for example, two or four times the frequency. The second switching frequency is preferably about 1000 times the first switching frequency, for example, when the first switching frequency is 50 [Hz], the second switching frequency is 50 [kHz], and when the first switching frequency is 60 [Hz], the second switching frequency is 60 [kHz]. Of course, when the first switching frequency is 50 [Hz], the second switching frequency may be 60 [kHz], and when the first switching frequency is 60 [Hz], the second switching frequency may be 50 [kHz].

[0030] For example, the first switching element 11S is a silicon switching element, and the second switching elements (21S, 22S, 23S) are high-speed switching elements such as silicon carbide switching elements, gallium nitride switching elements, and gallium oxide switching elements.

[0031] Although AC to DC conversion can be realized by a rectifier circuit using a rectifier element such as a diode, it is preferable to perform power conversion in a state where the power factor, which is determined by the phase of the AC voltage and current, is close to "1". In this embodiment, the active rectifier of the first circuit 1 is switched at the same frequency (commercial frequency) as the frequency of the AC power, and the first DC power, although it is a direct current, has pulsation almost equivalent to that of the AC power. For this reason, the second circuit 2 has a power factor correction function that improves the power factor by adjusting the voltage phase and current phase of the pulsating component (i.e., the AC power).

[0032] In the first circuit 1, which is switched at a first switching frequency, a large pulsating component remains in the DC power converted from the AC power, but the first DC power is generated by an active rectifier. Since the switching frequency of the first switching element 11S is low, about 50 to 60 Hz, the switching loss of the first circuit 1 is small.

[0033] The DC link capacitor Cdc arranged between the first circuit 1 and the second circuit 2 does not require a high smoothing function against pulsation, so its capacitance can be easily kept small. A capacitor arranged between the AC-DC converter and the DC-DC converter to smooth the DC voltage may require a capacitance of about 1000 [μF]. However, the capacitance of the DC link capacitor Cdc of this embodiment is sufficient with about 50 [μF].

[0034] The second circuit, which includes a triple active bridge circuit that is switched at a second switching frequency that is much higher than the first switching frequency, performs power factor correction as described above by high-speed switching, and attenuates the amplitude of the pulsating component superimposed on the first DC power to generate the second DC power and the third DC power. The high-speed switching can significantly reduce the amplitude of the pulsating component included in the first DC power. That is, the second circuit 2 has a function of generating a first battery voltage to be applied to the first DC power source 3 and a function of generating a second battery voltage to be applied to the second DC power source 30, in addition to the power factor correction function. Moreover, since the second circuit 2 can significantly reduce the amplitude of the pulsating component included in the first DC power, it can be said that it also has a pulsation reduction function.

[0035] In addition, the triple active bridge circuit of the second circuit 2 includes a transformer T, and the circuit (primary side circuit 2a) on the side of the external AC power source 4 is insulated from the circuit (secondary side circuit 2b) on the side of the first DC power source 3 and the second DC power source 30. In a configuration in which the external AC power source 4 and the DC power sources (the first DC power source 3 and the second DC power source 30) are not electrically independent from each other, a relatively high leakage current from the external AC power source 4 may flow to a common ground. Since a user or the like may be present near the vehicle during charging, it is preferable that such leakage current is also taken into consideration. In addition, in a configuration in which the external AC power source 4 and the DC power sources are not electrically independent from each other, when a short circuit failure or the like occurs in the external AC power source 4, a large short circuit current may flow to the first DC power source 3, the second DC power source 30, the in-vehicle device connected to the first DC power source 3, and the in-vehicle device connected to the second DC power source 30. The in-vehicle charging device 10 of this embodiment includes the transformer T to insulate the external AC power supply 4 side from the DC power supply side, thereby providing high safety.

[0036] As described above, the first switching element 11S, which is switched at a relatively low first switching frequency, is a general-purpose silicon (Si) switching element that is widely distributed and whose unit price has been reduced due to mass production effects. For example, it is a Si-MOSFET (Metal Oxide Semiconductor FET) or a Si-IGBT. These switching elements have sufficient performance to configure an active rectifier with a power factor correction function that is switched at the first switching frequency, and further, it is easy to reduce the cost of the in-vehicle charging device 10.

[0037] For the second switching elements (21S, 22S, 23S) that require switching operation at a high switching frequency, next-generation high-speed switching elements such as silicon carbide (SiC) switching elements, gallium nitride (GaN) switching elements, and gallium oxide (Ga2O3) switching elements are used. Examples include SiC-MOSFETs and GaN-HEMTs (High Electron Mobility Transistors). For example, gallium nitride switching elements are more likely to achieve high breakdown strength, faster switching speeds, higher thermal conductivity, and lower on-resistance than silicon switching elements of a comparable structure, for example, due to the high electrical conductivity of gallium nitride. Therefore, the second switching elements (21S, 22S, 23S) can achieve operation at a high switching frequency while also reducing the increase in switching loss associated with a high switching frequency.

[0038] As described above, the in-vehicle charging device 10 is configured to have a circuit equipped with switching elements, and these switching elements are switched and controlled by the charging control device 100. That is, the charging control device 100 controls the switching of the switching elements of the in-vehicle charging device 10 to charge the first DC power source 3 and the second DC power source 30. The charging control device 100 is configured to have various functional units, and each functional unit is realized by cooperation between hardware such as a microcomputer and software (programs). However, when performing switching control at a very high speed like the second circuit 2, the control cycle of the microcomputer may not be compatible, or even if it is compatible, a very expensive chip may have to be used. For this reason, hardware such as a field programmable gate array (FPGA), a programmable logic array (PLA), or a programmable logic device (PLD) may be used. The FPGA, PLA, and PLD also have hardware and a program that specifies the circuit configuration, and it can be said that the hardware and the software (program) cooperate with each other.

[0039] In the vehicle-mounted charging device 10 of this embodiment, the first circuit 1 is configured by a bridge circuit of a simple configuration including a first switching element 11S for which low-speed switching control is sufficient, and a DC link capacitor Cdc with a low capacity at the DC output section. The second circuit 2 is switched and controlled so as to minimize the total harmonic distortion (THD) at a second switching frequency that is much higher than that of the first circuit 1. That is, the vehicle-mounted charging device 10 of this embodiment can obtain a grid current with an input power factor close to "1", and can suppress the pulsating components so that the amplitudes of the pulsating components of both the first battery current flowing through the first DC power source 3 and the second battery current flowing through the second DC power source 30 are reduced.

[0040] Depending on the open / closed states of the main contactor 11, the grid contactor 13, and the second DC power supply connection contactor 14, a plurality of operation modes, as exemplified in Table 1 below, of the on-board system including the drive control system of the rotating electric machine 70 and the on-board charging system can be realized. Specifically, the operation modes include a mode in which the rotating electric machine 70 is driven by power supplied from the first DC power supply 3 (operation mode (MODE): TRACTION), a mode in which power is supplied from the first DC power supply 3 to the rotating electric machine 70 and power is supplied from the first DC power supply 3 to the second DC power supply 30 (operation mode: TRACTION & CHARGE), and a mode in which the first DC power supply 3 and the second DC power supply 30 are charged by AC power supplied from the external AC power supply 4 (operation mode: OBC). In the "TRACTION & CHARGE" operation mode, power is supplied from the first DC power supply 3 to the second DC power supply 30 via the secondary-side second bridge circuit 213. Therefore, the secondary side second bridge circuit 213 can also function as the voltage conversion circuit 33 shown in FIG.

[0041] "Contactor" in the table indicates the contactor described above, and the numbers correspond to the symbols indicating the contactors in the diagram. Incidentally, "operation mode: OFF" is a state in which the vehicle is stopped (parked) and the first DC power source 3 and the second DC power source 30 are not being charged. In addition, in the table, "close" indicates "closed" and "open" indicates "open."

[0042] [Table 1]

[0043] The schematic circuit block diagram of FIG. 3 shows a second example of the vehicle-mounted charging device 10. The vehicle-mounted charging device 10 of the second example is different from the first example in that it includes a chopper circuit 20 that converts the second DC power into a fourth DC power. The chopper circuit 20 includes a switching circuit 214 and a choke coil Le. The "choke coil" may be called a "reactor". The switching element 24S constituting the switching circuit 214 may be a general-purpose silicon switching element, similar to the first switching element 11S. The switching circuit 214 is configured as a half-bridge leg in which two switching elements 24S are connected in series. One end of the choke coil Le is connected to the midpoint of the switching circuit 214. The other end of the choke coil Le is connected to the first DC power source 3 via the charging device connection contactor 15 and the main contactor 11. With the charging device connection contactor 15 in a closed state, an output capacitor Co for smoothing the first battery voltage is connected between the other end of the choke coil Le and the ground of the chopper circuit 20. In the first example, the first capacitor Cs1 arranged between the secondary side first bridge circuit 212 and the first DC power source 3 for smoothing the first battery voltage is arranged between the secondary side first bridge circuit 212 and the switching circuit 214 of the chopper circuit in the second example.

[0044] As a result, the first DC power supply 3 is charged by the fourth DC power, not the second DC power as in the first example. The second DC power supply 30 is charged by the third DC power, as in the first example. The switching circuit 214 is switched by, for example, pulse width modulation control, so that the pulsation of the harmonic components of the frequency of the AC power in the first battery current flowing through the first DC power supply 3 is further reduced.

[0045] By providing the chopper circuit 20, the pulsation component in the fourth DC power can be further suppressed compared to the second DC power. The fourth DC power and the second DC power are both powers on the secondary side of the transformer T. The primary coil T1 and the secondary first coil T21 are electromagnetically coupled, and the pulsation of the fourth DC power in the chopper circuit 20 connected to the secondary first coil T21 is suppressed, so that the pulsation of the DC power (second DC power) appearing in the secondary second coil T22 electromagnetically coupled to the primary coil T1 is also suppressed. That is, the chopper circuit 20 functions as a DC step-down converter and an active harmonic filter.

[0046] Although not shown in the drawings, a chopper circuit 20 may be disposed between the secondary side second bridge circuit 213 and the second DC power source 30, and the second DC power source 30, rather than the first DC power source 3, may be charged with DC power (fourth DC power) further converted via the chopper circuit 20. In this case, the first DC power source 3 is charged with the second DC power output from the secondary side first bridge circuit 212.

[0047] That is, the in-vehicle charging device 10 of the second example includes a chopper circuit 20 including a switching circuit 214 and a choke coil Le, and converts the second DC power into a fourth DC power, or includes a chopper circuit 20 including a switching circuit 214 and a choke coil Le, and converts the third DC power into the fourth DC power. When the chopper circuit 20 converts the second DC power into the fourth DC power, the first DC power source 3 is charged with the fourth DC power, and the second DC power source 3 is charged with the fourth DC power. In the case where the first battery current flowing through the first DC power supply 3 and the second battery current flowing through the second DC power supply 30 are charged with the third DC power and the chopper circuit 20 converts the third DC power into the fourth DC power, it is preferable that the first DC power supply 3 is charged with the second DC power and the second DC power supply 30 is charged with the fourth DC power, and the switching circuit 214 is switched and controlled so that pulsation of harmonic components of the AC power frequency in the first battery current flowing through the first DC power supply 3 and the second battery current flowing through the second DC power supply 30 is reduced.

[0048] Table 2 below shows examples of operation modes of the drive control system for the rotating electrical machine 70 and the on-board system including the on-board charging system, including the open / closed state of the charging device connection contactor 15.

[0049] [Table 2]

[0050] The schematic circuit block diagram of FIG. 4 shows a third example of the vehicle-mounted charging device 10. The vehicle-mounted charging device 10 of the third example is different from the second example in that the chopper circuit 20 is configured using the stator coil 7 of the rotating electric machine 70 and the inverter 5 that drives the rotating electric machine 70. The vehicle-mounted charging device 10 tends to have a large circuit size, but there are fewer opportunities to charge the DC power sources (the first DC power source 3 and the second DC power source 30) compared to opportunities to drive the wheels. Therefore, it is preferable that the vehicle-mounted charging device 10 has a configuration as small as possible. When the external AC power source 4 is connected to charge the DC power source, the vehicle is stopped (parked). Therefore, the inverter 5 configured with a switching element and the stator coil 7 of the rotating electric machine 70 having inductance are not used to drive the wheels when charging the DC power source. By configuring the vehicle-mounted charging device 10 using the inverter 5 and the stator coil 7, it is possible to suppress an increase in the overall size of the vehicle-mounted system.

[0051] Specifically, when the first DC power source 3 is connected to a rotating electric machine 70 having multiple phase stator coils 7 connected to each other at a neutral point 7N via an inverter 5 that converts power between DC and AC, the chopper circuit 20 is configured as follows. As is clear from a comparison between FIG. 3 and FIG. 4, the switching circuit 214 is configured using the inverter 5. The upper-stage switching elements and the lower-stage switching elements of the inverter 5 are each collectively turned on and off so as to be in the same state, so that the three-leg inverter 5 can be regarded as one leg. In addition, the choke coil Le is configured using multiple phase stator coils 7, and the neutral point 7N of the multiple phase stator coils 7 is connected to the positive electrode of the first DC power source 3.

[0052] When the in-vehicle charging device 10 is configured as in the third example, the output capacitor Co may also serve as the decoupling capacitor 6 in the rotating electric machine control system. The rotating electric machine control device 80 may also function as the charging control device 100. In addition, in common to the first to third examples, the vehicle control device 90 may function as a part or the whole of the charging control device 100.

[0053] Since the inverter 5 is also used as the chopper circuit 20, a first function switching contactor 16 and a second function switching contactor 17 are further provided to connect and disconnect the electrical connection between the inverter 5 and the second circuit 2. Since the stator coil 7 is also used, a contactor is also required to connect and disconnect the electrical connection between the neutral point 7N of the stator coil 7 and the first DC power source 3. The charging device connection contactor 15 described above can be used as this contactor.

[0054] Further, the operation modes of the on-board system including the drive control system of the rotating electric machine 70 and the on-board charging system, including the open / closed states of the first function switching contactor 16 and the second function switching contactor 17, are illustrated in Table 3 below.

[0055] [Table 3]

[0056] As described above, the second DC power source 30 may be configured to supply power to a compressor or an electric oil pump of an air conditioner. In such a configuration, a motor (rotating electric machine) is provided to drive the compressor or the oil pump. The motor is provided with an inverter to drive the motor. Although illustration and detailed description are omitted because it is clear from FIG. 1, an inverter or a stator coil of a motor may be provided for the second DC power source 30 as in the first DC power source 3. Therefore, in the on-board charging device 10 of the third example, the chopper circuit 20 may be configured using a stator coil or an inverter of a motor provided for the second DC power source 30.

[0057] That is, in the third example of the on-board charging device 10, a target DC power source, which is one of the first DC power source 3 and the second DC power source 30 and is to be charged with a fourth DC power, is connected to a rotating electric machine (rotating electric machine 70 or a motor for driving a compressor or an oil pump) having multiple phase stator coils connected to each other at a neutral point via an inverter that converts power between DC and AC, and it is preferable that the chopper circuit 20, the switching circuit 214 is constructed using an inverter, the choke coil Le is constructed using multiple phase stator coils, and the neutral point of the multiple phase stator coils is connected to the positive electrode of the target DC power source.

[0058] Incidentally, in common to the first to third examples, the input inductor Li may be provided in the second circuit 2 instead of the first circuit 1, as in a fourth example shown in FIG. 5, and may be connected between a midpoint of one leg of the primary side bridge circuit 211 and one end of the primary side coil T1. Similarly, in common to the first to third examples, the input inductor Li may be a first input inductor Li1 and a second input inductor Li2 provided in the second circuit 2 instead of the first circuit 1, as in a sixth example shown in FIG. 6. As shown in FIG. 6, the first input inductor Li1 is connected between a midpoint of one leg of the secondary side first bridge circuit 212 and one end of the secondary side first coil T21, and the second input inductor Li2 is connected between a midpoint of one leg of the secondary side second bridge circuit 213 and one end of the secondary side second coil T22.

[0059] In circuits that use switching elements, switching losses increase as the switching frequency increases. When a switching element is on, the voltage between the input and output terminals of the switching element (between drain and source, between collector and emitter) is nearly zero, and current flows between the input and output terminals. When a switching element is off, the current flowing between the input and output terminals of the switching element is nearly zero, and a voltage is applied between the input and output terminals. Whether the switching element is on or off, the power (loss), expressed as the product of the current and voltage, is nearly zero.

[0060] When a switching element changes from an on state to an off state (i.e., when it is turned off), the voltage rises and the current falls. When a switching element changes from an off state to an on state (i.e., when it is turned on), the voltage falls and the current rises. Therefore, during the state change at the time of turning off and on, there is a period in which the current and voltage are not nearly zero. Therefore, during the state change, the power (loss) represented by the product of the current and the voltage is not zero. And when the switching frequency is high, the number of times of turning on and off also increases, so the loss also tends to increase. In this way, switching in which the voltage and current of the switching element change suddenly at the time of turning on and off is called hard switching, and generally has a large power loss.

[0061] As is clear from the fact that loss (power) is expressed by the product of voltage and current, if either the current or the voltage is almost zero during switching, the product will be almost zero even if the other changes from zero. For example, ZVS (Zero Voltage Switching) is known, which makes the voltage between the input and output terminals of a switching element almost zero during switching, and ZCS (Zero Current Switching) is known, which makes the current flowing through the switching element almost zero. ZVS and ZCS are called soft switching in contrast to hard switching. The principles and concepts of soft switching are well known, so a detailed explanation will be omitted, but in order to realize soft switching, a capacitive element or an inductive element is required in the switching circuit.

[0062] In the first, second and third examples, the first circuit 1 is provided with an input inductor Li which is an inductive element, and the second circuit 2 is not provided with any inductive elements except for the transformer T. Therefore, the switching circuits (the primary side bridge circuit 211, the secondary side first bridge circuit 212 and the secondary side second bridge circuit 213) in the second circuit 2 are switched by hard switching. In contrast, in the fourth and fifth examples, the second circuit 2 is provided with inductive elements (the input inductor Li, the first input inductor Li1 and the second input inductor Li2) and can be switched by soft switching.

[0063] As described above, the second circuit 2 is switched at a second switching frequency that is much higher than that of the first circuit 1. In addition, as the switching frequency increases, the switching loss increases, and the loss in the second circuit 2 tends to become very large. By disposing an inductive element in the second circuit 2, the second circuit 2 can be switched by soft switching, and the loss in the in-vehicle charging device 10 can be significantly reduced.

[0064] The second circuit 2 is not limited to the fourth and fifth examples shown in Figures 5 and 6, and may, for example, include an input inductor Li in the primary side circuit 2a and a first input inductor Li1 and a second input inductor Li2 in the secondary side circuit 2b.

[0065] In recent years, it has been proposed to use the DC power source of an electric vehicle or a hybrid vehicle as an emergency power source in the event of a disaster or the like. For example, when the first DC power source 3 is configured to be usable as a power source of an emergency power source, the second circuit 2 functions as a dual active bridge DC / DC DAB (Dual Active Bridge) Buck Converter from the first circuit 1 to the first DC power source 3, and functions as a dual active bridge DC / DC DAB Boost Converter from the first DC power source 3 to the first circuit 1. The first circuit 1 also includes a full bridge circuit 111, and can function as a bidirectional power converter having a function of converting DC to AC in addition to a function of converting AC to DC. That is, the first circuit 1 performs DC / AC conversion, and commercial AC power can be output from the first circuit 1, and the first DC power source 3 can be used as an emergency power source.

[0066] In common with the first to third examples, the vehicle-mounted charging device 10 of the present embodiment is configured to be capable of bidirectional power conversion, that is, power conversion from AC to DC (second DC power, third DC power, fourth DC power) and power conversion from DC (second DC power in the first example, fourth DC power in the second and third examples) to AC. Specifically, the vehicle-mounted charging device 10 of the first example can be configured as follows. When the vehicle-mounted charging device 10 charges the first DC power source 3 and the second DC power source 30 by the external AC power source 4, the first circuit 1 functions as a unity power factor AC / DC boost converter UPF (Unity Power Factor), and the second circuit 2 functions as a triple active bridge DC / DC TAB Buck converter. When the in-vehicle charging device 10 functions, for example, as an emergency AC power source that outputs AC power using the power stored in the first DC power source 3, the second circuit 2 functions as a dual active bridge DC / DC boost converter (DC / DC DAB Boost Converter) (structurally a triple active bridge (TAB)), and the first circuit 1 functions as a single power factor DC / AC buck converter (UPF).

[0067] In the second and third examples, a chopper circuit 20 is further provided. When the in-vehicle charging device 10 charges the first DC power source 3 and the second DC power source 30 using the external AC power source 4, the chopper circuit 20 functions as a DC / DC buck converter. When the in-vehicle charging device 10 functions as an emergency AC power source that outputs AC power using power stored in the first DC power source 3, for example, the chopper circuit 20 functions as a DC / DC boost converter.

[0068] In the present embodiment, as described above, the vehicle-mounted charging device 10 is configured as a device capable of bidirectional power conversion. In the case where the vehicle-mounted charging device 10 is a device that performs only AC to DC power conversion (second DC power, third DC power, fourth DC power), the first circuit 1 may be configured to include a diode full-bridge rectifier circuit without including a full-bridge circuit formed by the first switching element 11S.

[0069] The following is a brief summary of the vehicle-mounted charging device (10) described above.

[0070] In one embodiment, the vehicle-mounted charging device (10) charges a first DC power source (3) and a second DC power source (30) electrically insulated from the first DC power source (3) with power supplied from an external AC power source (4), and includes a first circuit (1) that converts AC power on the side of the external AC power source (4) into first DC power, and a second circuit (2) that converts the first DC power into second DC power on the side of the first DC power source (3) and converts the first DC power into third DC power on the side of the second DC power source (30). and a DC link capacitor (Cdc) arranged between the first circuit (1) and the second circuit (2) to smooth a first DC voltage in the first DC power, the first circuit (1) comprising a full bridge circuit (111) configured using a first switching element (11S) and an input inductor (Li) connected between a midpoint of one leg of the full bridge circuit (111) and the external AC power source (4), the second circuit (2) comprising a primary side coil (T1) and a secondary side first coil (T2 a transformer (T) including a primary coil (T1) and a secondary second coil (T22), a primary bridge circuit (211) connected to the primary coil (T1), and a secondary second bridge circuit (212) connected to the secondary second coil (T21), and the triple active bridge circuit has at least a power factor correction function for the AC power, a function for generating a first battery voltage to be applied to the first DC power source, and a function for generating a second battery voltage to be applied to the second DC power source, The secondary side first bridge circuit (212) and the secondary side second bridge circuit (213) are configured using second switching elements (21S, 22S, 23S) different from the first switching element (11S), the first switching element (11S) is switching-controlled at a first switching frequency corresponding to a commercial frequency which is the frequency of the AC power, and the second switching elements (21S, 22S, 23S) are switching-controlled at a second switching frequency of 10 kHz or more which is higher than the commercial frequency.

[0071] According to this configuration, in the first circuit (1) in which switching is controlled at a first switching frequency corresponding to the commercial frequency, the first DC power can be obtained, although a large pulsating component remains in the DC power converted from the AC power. Since the first switching element (11S) is switching controlled at the first switching frequency, the switching loss of the first circuit (1) can be easily kept low. In the second circuit (2) having a triple active bridge circuit in which switching is controlled at a second switching frequency that is about 1000 times faster than the first switching frequency, the current phase and voltage phase in the first DC power in which a large AC component remains can be adjusted by high-speed switching to improve the power factor, and further, the amplitude of the pulsating component superimposed on the first DC power can be easily attenuated, and appropriate second DC power and third DC power can be obtained. In addition, since the first DC power output from the first circuit (1) does not require a large reduction in the pulsating component, the capacitance of the DC link capacitor (Cdc) arranged between the first circuit (1) and the second circuit (2) can be easily kept small. Therefore, the size of the DC link capacitor (Cdc) can be easily kept small, and the scale of the on-board charging device (10) can also be easily kept small. In addition, the triple active bridge circuit includes a transformer (T), and the circuit on the external AC power source (4) side is insulated from the circuits on the first DC power source (3) and second DC power source sides, which makes it easy to improve safety. Thus, according to this configuration, the on-board charging device (10) that charges the on-board DC power source (3, 30) with power from the external AC power source (4) can be configured with reduced system costs while ensuring safety.

[0072] It is preferable that the input inductor (Li) is provided in the second circuit (2) instead of the first circuit (1) and is connected between a midpoint of one leg of the primary side bridge circuit (211) and one end of the primary side coil (T1). Alternatively, it is preferable that the input inductor (Li) is a first input inductor (Li1) and a second input inductor (Li2) provided in the second circuit (2) instead of the first circuit (1), and the first input inductor (Li1) is connected between a midpoint of one leg of the secondary side first bridge circuit (212) and one end of the secondary side first coil (T21), and the second input inductor (Li2) is connected between a midpoint of one leg of the secondary side second bridge circuit (213) and one end of the secondary side second coil (T22).

[0073] As described above, the second circuit (2) is switched at a second switching frequency higher than that of the first circuit (1). When the switching frequency is high, the switching loss is high. Techniques for reducing the switching loss include ZVS (Zero Voltage Switching), which brings the voltage between the input and output terminals (between the drain and source, between the collector and emitter) of the switching element closer to zero during switching, and soft switching accompanied by ZCS (Zero Current Switching), which brings the current flowing through the switching element closer to zero. By providing the second circuit (2) with input inductors (Li, LI1, Li2), soft switching can be performed in the switching control of the second circuit (2), and it is easy to significantly reduce the switching loss in the second circuit (2) which is switched at a second switching frequency higher than that of the first circuit (1). Therefore, it is easy to reduce the loss in the in-vehicle charging device (100).

[0074] Here, it is preferable that the first switching element (11S) is a silicon switching element, and the second switching elements (21S, 22S, 23S) are high-speed switching elements including silicon carbide switching elements, gallium nitride switching elements, and gallium oxide switching elements.

[0075] Silicon switching elements are widely distributed, and the unit price of parts has been reduced due to mass production. Therefore, by using silicon switching elements as the first switching elements (11S) that do not require operation at a high switching frequency, it is easy to reduce the cost of the in-vehicle charging device (10). On the other hand, the second switching elements (21S, 22S, 23S) are required to perform switching operations at a high switching frequency. For example, gallium nitride switching elements, due to their high electrical conductivity, tend to achieve high breakdown strength, faster switching speed, higher thermal conductivity, and lower on-resistance compared to silicon switching elements of a similar structure. Silicon carbide switching elements and gallium oxide switching elements also tend to achieve faster switching speeds and lower losses compared to silicon switching elements. Therefore, by using these switching elements as the second switching elements (21S, 22S, 23S), it is possible to achieve operation at a high switching frequency and reduce the increase in switching loss associated with a high switching frequency.

[0076] The in-vehicle charging device (10) further includes a chopper circuit (20) including a switching circuit (214) and a choke coil (Le) and configured to convert the second DC power into a fourth DC power, or a chopper circuit (20) including a switching circuit (214) and a choke coil (Le) and configured to convert the third DC power into the fourth DC power, and when the chopper circuit (20) converts the second DC power into the fourth DC power, the first DC power source (3) is charged with the fourth DC power and the second DC power source (30) is In a case where the first DC power source is charged with the third DC power and the chopper circuit (20) converts the third DC power into a fourth DC power, it is preferable that the first DC power source is charged with the second DC power and the second DC power source is charged with the fourth DC power, and the switching circuit (214) is switched and controlled so that pulsation of harmonic components of the frequency of the AC power is reduced in a first battery current flowing in the first DC power source (3) and a second battery current flowing in the second DC power source (30).

[0077] By providing the chopper circuit (20) between the second circuit (2) and the first DC power source (3), the pulsation component of the fourth DC power can be made smaller than that of the second DC power or the third DC power. The fourth DC power and the second DC power or the third DC power are both powers on the secondary side of the transformer T. The primary coil T1 and the secondary first coil T21 are electromagnetically coupled, and the pulsation of the fourth DC power in the chopper circuit 20 connected to the secondary first coil T21 is suppressed, so that the pulsation of the DC power (the third DC power or the second DC power) appearing in the secondary first coil T21 or the secondary second coil T22 electromagnetically coupled to the primary coil T1 is also suppressed.

[0078] In addition, it is preferable that a target DC power source, of the first DC power source (3) and the second DC power source (30), which is charged with the fourth DC power, is connected to a rotating electric machine (70) having multiple phases of stator coils (7) connected to each other at a neutral point (7N) via an inverter (5) that converts power between DC and AC, and that the chopper circuit (20) has a switching circuit (214) configured using the inverter (5), a choke coil (Le) configured using the multiple phases of the stator coils (7), and the neutral point (7N) of the multiple phases of the stator coils (7) is connected to the positive electrode of the target DC power source.

[0079] According to this configuration, the target DC power source connected to the rotating electric machine (70) can be charged by using both the stator coil (7) of the rotating electric machine (70) and the inverter (5) that drives and controls the rotating electric machine (70). By using these in combination, the in-vehicle charging device (10) can be configured to be small in size. [Explanation of symbols]

[0080] 1: first circuit, 2: second circuit, 3: first DC power supply, 4: external AC power supply, 5: inverter, 6: decoupling capacitor (DC link capacitor), 7: stator coil, 7N: neutral point, 10: on-board charging device, 11S: first switching element, 14S: switching element, 20: chopper circuit, 21: chopper circuit, 21S: switching element, 22S: switching element, 23S: switching element, 30: second DC power supply, 70: rotating current machine, 111: full bridge circuit, 211: primary side bridge circuit, 212: secondary side first bridge circuit, 213: secondary side second bridge circuit, 214: switching circuit, 222: secondary side second bridge circuit, Cdc: DC link capacitor, Le: choke coil, Li: input inductor, Li1: first input inductor, Li2: second input inductor, T: transformer, T1: primary side coil, T21: secondary side first coil, T22: secondary side second coil

Claims

1. An in-vehicle charging device that charges a first DC power source and a second DC power source electrically insulated from the first DC power source with power supplied from an external AC power source, a first circuit that converts AC power from the external AC power source into a first DC power; a second circuit that converts the first DC power into a second DC power on the side of the first DC power source and converts the first DC power into a third DC power on the side of the second DC power source; a DC link capacitor disposed between the first circuit and the second circuit to smooth a first DC voltage in the first DC power; The first circuit is a full bridge circuit configured using a first switching element; an input inductor connected between a midpoint of one leg of the full bridge circuit and the external AC power supply; The second circuit is A transformer including a primary coil, a first secondary coil, and a second secondary coil; A primary bridge circuit connected to the primary coil; a secondary side first bridge circuit connected to the secondary side first coil; a secondary-side second bridge circuit connected to the secondary-side second coil, comprising a triple active bridge circuit having at least a power factor correction function for the AC power, a function for generating a first battery voltage to be applied to the first DC power source, and a function for generating a second battery voltage to be applied to the second DC power source; the primary side bridge circuit, the secondary side first bridge circuit, and the secondary side second bridge circuit are configured using second switching elements different from the first switching elements, the first switching element is switched at a first switching frequency corresponding to a commercial frequency which is a frequency of the AC power, The second switching element is switched at a second switching frequency of 10 kHz or more higher than the commercial frequency.

2. The input inductor is provided in the second circuit instead of the first circuit and is connected between a midpoint of one leg of the primary bridge circuit and one end of the primary coil, or the input inductor is a first input inductor and a second input inductor provided in the second circuit instead of the first circuit, the first input inductor is connected between a midpoint of one leg of the secondary side first bridge circuit and one end of the secondary side first coil; The in-vehicle charging device according to claim 1 , wherein the second input inductor is connected between a midpoint of one leg of the secondary side second bridge circuit and one end of the secondary side second coil.

3. the first switching element is a silicon switching element; The in-vehicle charging device according to claim 1 or 2, wherein the second switching element is a high-speed switching element including a silicon carbide switching element, a gallium nitride switching element, and a gallium oxide switching element.

4. a chopper circuit including a switching circuit and a choke coil and converting the second DC power into a fourth DC power, or a chopper circuit including a switching circuit and a choke coil and converting the third DC power into a fourth DC power; When the chopper circuit converts the second DC power into the fourth DC power, the chopper circuit charges the first DC power source with the fourth DC power and charges the second DC power source with the third DC power; When the chopper circuit converts the third DC power into the fourth DC power, the chopper circuit charges the first DC power source with the second DC power and charges the second DC power source with the fourth DC power; 3. The in-vehicle charging device according to claim 1, wherein the switching circuit is switched-controlled so that pulsation of harmonic components of a frequency of the AC power in a first battery current flowing through the first DC power source and a second battery current flowing through the second DC power source is reduced.

5. a target DC power source, which is one of the first DC power source and the second DC power source and is to be charged by the fourth DC power, is connected to a rotating electric machine having a plurality of stator coils connected to each other at a neutral point via an inverter that converts power between DC and AC; The chopper circuit includes: The switching circuit is configured using the inverter, The choke coil is configured using the stator coil of a plurality of phases, The on-board charging device according to claim 4 , wherein the neutral points of the stator coils of the multiple phases are connected to a positive electrode of the target DC power source.

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