On-vehicle charging device

Abstract

To configure an on-vehicle charging device charging an on-vehicle DC power source with power from an external AC power source utilizing a coil and an inverter of an on-vehicle rotary electric machine, while having higher safety and suppressing an increase in system cost.SOLUTION: A first circuit 1 for converting power between AC power at the side of an external AC power source 4 and first DC power comprises: an input inductor Li which is configured using a plurality of coils 7 of a rotary electric machine; and a full-bridge active rectifier of which one arm 1a is configured using an inverter 5. A second circuit 2 for generating second DC power from the first DC power comprises: a transformer T including a primary-side coil T1 and a secondary-side coil T2; and a dual active bridge circuit including a primary-side bridge circuit 21 connected to the first circuit 1 and the primary-side coil T1 and a secondary-side bridge circuit 22 connected to a DC power source 3 and the secondary-side coil T2.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 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 DC power source is mounted on the vehicle (reference symbols in parentheses in the background art are those of the referenced document). FIG. 3 of this document illustrates an onboard charging device in which an external AC power source (310) is connected to the neutral point of a Y-connected three-phase coil, each of the three phase coils is connected to each AC side arm of an inverter (220), an input side terminal of a DC / DC converter is connected to a DC side terminal of the inverter (220), and a DC power source is connected to an output side terminal of the DC / DC converter. The three-phase coils and the inverter (220) form an AC / DC converter that converts a sine wave grid current from the external AC power source (310) into DC. By controlling the switching of the inverter (220), the AC-DC converter also functions as a power factor correction (PFC) circuit that improves the power factor of the DC power converted from the AC power. A ripple occurs in the current after the AC-DC conversion, the frequency of which is twice the frequency (system frequency) of the external AC power source (310). The DC-DC converter reduces this ripple and generates a battery current for charging the DC power source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-503713 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, for example, in an on-board charging device for an electric vehicle or a hybrid vehicle, a coil (stator coil) provided in a stator of a rotating electric machine that is a driving force source for the wheels of the vehicle can be used as the three-phase coil. FIG. 6 shows an example of a charging device 10X that is a conventional example of such an on-board charging device. The charging device 10X is configured to share the coil 7 of the rotating electric machine 70 that is a driving force source for the wheels and the inverter 5 that drives and controls the rotating electric machine 70. The charging device 10X is configured to have a first circuit 1 equipped with an AC-DC converter and a second circuit 2 equipped with a DC-DC converter. The first circuit 1 is configured using the coil 7 and the inverter 5, and an external AC power source 4 is connected to the neutral point 7N of the multiple-phase coils 7 of the rotating electric machine 70. The first circuit 1 and the second circuit 2 are selectively connected via a function switching contactor 12. When the coil 7 and the inverter 5 are used to drive the wheels, the first function switching contactor contact 12a is closed, and when the coil 7 and the inverter 5 are used to charge the DC power source 3, the second function switching contactor contact 12b is closed.

[0005] However, in a configuration in which the external AC power supply 4 and the DC power supply 3 are not electrically independent from each other, a relatively high leakage current may flow from the external AC power supply 4 to the common ground. Since a user or the like may be present near the vehicle while the DC power supply 3 is being charged, it is preferable to take such leakage current into consideration. Furthermore, in a configuration in which the external AC power supply 4 and the DC power supply 3 are not electrically independent from each other, if a short circuit or other fault occurs in the external AC power supply 4, a large short circuit current may flow to the DC power supply 3 and the in-vehicle device connected to the DC power supply 3.

[0006] In view of the above background, it is desirable to configure an on-board charging device that uses the coil and inverter of an on-board rotating electric machine to charge an on-board DC power supply with power from an external AC power supply, while providing greater safety and suppressing increases in system costs. [Means for solving the problem]

[0007] In view of the above, an on-board charging device is mounted on a vehicle including a rotating electric machine having coils of multiple phases connected to each other at a neutral point, an inverter that converts power between DC and multiple-phase AC, and a DC power source connected to the rotating electric machine via the inverter, and charges the DC power source with power supplied from an external AC power source, the on-board charging device including: a first circuit that converts power between AC power on the side of the external AC power source and first DC power; and a second circuit that generates second DC power from the first DC power for charging the DC power source, the first circuit being disposed on the side of the external AC power source. the second circuit comprises a dual active bridge circuit including a transformer having a primary coil and a secondary coil, a primary bridge circuit connected to the first circuit and the primary coil, and a secondary bridge circuit connected to the DC power supply and the secondary coil, the input inductor being configured using a plurality of the coils, and one of the two arms of the full-bridge active rectifier being configured using the inverter.

[0008] According to this configuration, the DC power supply and the external AC power supply are insulated by providing a transformer in the second circuit. Therefore, it is easy to ensure the safety of the user against leakage current from the external AC power supply. In addition, when a short circuit or the like occurs in the external AC power supply, it is possible to reduce the possibility that a large short-circuit current will flow to the DC power supply and the in-vehicle device connected to the DC power supply. Thus, according to this configuration, it is possible to configure an in-vehicle charging device that uses the coil and inverter of the in-vehicle rotating electric machine to charge the in-vehicle DC power supply with power from the external AC power supply, with higher safety and suppressing increases in system costs.

[0009] 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]

[0010] [Figure 1] Schematic circuit block diagram of a drive control system for a rotating electric machine [Diagram 2] A circuit block diagram showing a first example of an on-board charging device using a drive control system for a rotating electric machine. [Diagram 3] A circuit block diagram showing a second example of an on-board charging device using a drive control system for a rotating electric machine. [Figure 4] A circuit block diagram showing a third example of an on-board charging device using a drive control system for a rotating electric machine. [Diagram 5] A circuit block diagram showing a fourth example of an on-board charging device using a drive control system for a rotating electric machine. [Figure 6] A circuit block diagram showing an example of a conventional charging device using a drive control system for a rotating electric machine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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 drive control system of 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 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. In addition to the rotating electric machine 70, the vehicle may also have other driving force sources such as an internal combustion engine (not shown) as a driving force source for the wheels. The rotating electric machine 70 is a rotating electric machine that has multiple phase coils 7 connected to each other at a neutral point 7N. The rotating electric machine 70 is connected to a DC power source 3 via an inverter 5 that converts power between DC and multiple phase AC. Details will be described later, but the vehicle-mounted charging device 10 of this embodiment is configured by using the coils 7 of the rotating electric machine 70 and the inverter 5 in a part of the circuit.

[0012] As shown in FIG. 1, the vehicle includes a control device 80 that controls a rotating electric machine 70, and the 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 multi-phase (N phases, where N is any natural number; in this embodiment, a three-phase form with N=3 is illustrated) stator coil (coil 7) 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) in which three-phase 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.

[0013] As shown in FIG. 1, the rotating electric machine 70 and the DC power supply 3 are connected via an inverter 5. The inverter 5 converts power between multiple-phase AC and DC. In this embodiment, the inverter includes a U-phase arm, a V-phase arm, and a W-phase arm as multiple-phase arms (which may also be called legs). Each arm 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 arm, that is, the connection point between the upper-stage switching element and the lower-stage switching element, is connected to the 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.

[0014] A decoupling capacitor (DC link capacitor 6) that smoothes the voltage (DC link voltage) between the positive and negative poles is provided on the DC side of the inverter 5. That is, the DC link capacitor 6 is connected in parallel to the DC power supply 3.

[0015] The 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 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 DC power source 3 is configured so that the electrical connection to the inverter 5 can be made and broken by operating a main switch (ignition switch) of the vehicle, or the like. For example, the DC power source 3 is connected to the inverter 5 via a main contactor 11 configured of 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.

[0016] As shown in Fig. 1, the vehicle is equipped with a DC power supply 3 connected to a rotating electric machine 70, as well as a low-voltage DC power supply 30 having a lower rated voltage than the DC power supply 3. The rated power supply voltage of the low-voltage DC power supply 30 is approximately 12 to 400 volts. As shown in Fig. 1, the low-voltage DC power supply 30 can be charged with the power of the DC power supply 3 via a voltage conversion circuit 33 configured around a DC-DC converter or the like.

[0017] For example, when the rated voltage of the DC power supply 3 is a high voltage of about 800 volts, it is preferable that the rated voltage of the low-voltage 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 low-voltage DC power supply. As will be described later, a DC power supply with an even lower rated voltage, for example, about 12 to 24 volts, is also required for the vehicle. Therefore, when the rated voltage of the low-voltage DC power supply 30 exceeds 24 volts, a second low-voltage DC power supply may be further provided.

[0018] Furthermore, for example, when the rated voltage of the DC power supply 3 is about 200 to 400 volts, it is preferable that the rated voltage of the low-voltage DC power supply 30 is 12 to 24 volts. In this case, the low-voltage DC power supply 30 supplies power to, for example, the indicators of the vehicle, the instrument panel, the lighting device, the audio system, and electronic circuits of the control device 80 and the vehicle control device 90. When the rated voltage of the DC power supply 3 is about 200 to 400 volts, it is preferable that the compressor of the air conditioner and the electric oil pump are supplied with power from the DC power supply 3. Note that, when the rated voltage of the low-voltage DC power supply 30 is 12 to 24 volts, it may be, for example, a lead-acid battery, as in a conventional vehicle in which an internal combustion engine is used as a driving force source for the wheels.

[0019] As shown in Fig. 1, the inverter 5 is configured to have a plurality of switching elements. Fig. 1 illustrates an example in which an IGBT (Insulated Gate Bipolar Transistor) is used as the switching element, but as illustrated in Fig. 2 and the like, a FET (Field Effect Transistor) may be used. In Fig. 1 and the like, a freewheel diode is connected in parallel to each switching element with the forward direction being the direction from the negative electrode to the positive electrode (the direction from the lower stage to the upper stage). Of course, when a body diode is used or when reverse conduction in a transistor of a wide band gap semiconductor made of enhancement mode gallium nitride (E-GaN) is used, such a freewheel diode may not be provided.

[0020] As shown in FIG. 1, the inverter 5 is controlled by a 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 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, the control device 80 may be considered to include a drive circuit.

[0021] The actual current flowing through the coils 7 of each phase of the rotating electric machine 70 is detected by a current sensor 81, and the 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 control device 80 acquires the detection results. The control device 80 executes current feedback control using the detection results of the current sensor 81 and the rotation sensor 82. The 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).

[0022] In the present embodiment, the on-board charging device 10 controls the inverter 5 controlled by the control device 80. Therefore, the control device 80 also controls the on-board charging device 10. The main contactor 11 may also be controlled by the vehicle control device 90, and both the vehicle control device 90 and the on-board charging device 10 can be controlled. That is, the control devices that control the on-board charging device 10 include at least the control device 80, and preferably include the control device 80 and the vehicle control device 90.

[0023] As described above, the rotating electric machine 70 connected to the DC power source 3 via the inverter 5 functions as an electric motor by the power supplied from the DC power source 3, and can also 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 or the like to cause the rotating electric machine 70 to generate electricity, but there are cases where the 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 DC power source 3 cannot be sufficiently charged in many cases. Also, in a hybrid vehicle, there are cases where it is more energy efficient to supply power from an external source than to have the rotating electric machine 70 generate electricity. For this reason, it is preferable that the DC power source 3 be configured to be charged by an external power source when the DC power source 3 is mounted on the vehicle.

[0024] When the DC power supply 3 is charged by an external power supply, it is preferable that an on-board charging device is installed in the vehicle. In many cases, the external power supply is AC because it receives power from a commercial power supply. For this reason, 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 equipped with an inductor and a bridge circuit composed of switching elements is known. Although the conversion from AC to DC can be realized by a rectifier circuit using a rectifier element such as a diode, it is preferable that the power conversion is performed in a state where the power factor, which is determined by the phase of the AC voltage and current, is close to "1". For this reason, the AC-DC converter often includes a power factor correction circuit using a switching element so that the power factor can be improved.

[0025] An on-board charging device equipped with such a power conversion circuit tends to have a large circuit scale, but there are fewer opportunities to charge the DC power source 3 compared to driving the wheels. Therefore, it is preferable that the on-board charging device has a small-scale configuration. When charging the DC power source 3 from an external power source, the vehicle is stopped (parked). Therefore, the inverter 5 formed of a switching element and the coil 7 of the rotating electric machine 70 having inductance are not used to drive the wheels when charging the DC power source 3 from an external power source. Therefore, it is conceivable to use the inverter 5 and the coil 7 to configure an on-board charging device.

[0026] FIG. 6 shows an example of a charging device 10X, which is a conventional example of such an on-board charging device. The charging device 10X is configured to share the coil 7 of a rotating electric machine 70 and the inverter 5 that drives and controls the rotating electric machine 70. The charging device 10X is configured to have a first circuit 1 equipped with an AC / DC converter and a second circuit 2 equipped with a DC / DC converter using a chopper circuit. The first circuit 1 is configured as a boost type AC / DC converter (AC / DC Boost Converter) equipped with an input inductor Li using the coil 7 and a full-bridge active rectifier using the inverter 5. The second circuit 2 is configured as a step-down type DC / DC converter (DC / DC Buck Converter) equipped with a step-down chopper.

[0027] As shown in FIG. 6, an external AC power supply 4 is connected to a neutral point 7N of a multi-phase coil 7. The full-bridge active rectifier also includes a full bridge 1c composed of a first arm 1a (first leg) and a second arm 1b (second leg). The first arm 1a is formed by three arms (legs) of an inverter 5. The three upper-stage switching elements of the inverter 5 are switched and controlled together, and the three lower-stage switching elements are switched and controlled together, so that the inverter 5 having arms of multiple phases can be regarded as a single-phase arm. In other words, the inverter 5 can appear to have one arm.

[0028] The first circuit 1 and the second circuit 2 are selectively connected via a function switching contactor 12. When the coil 7 and the inverter 5 are used to drive the wheels, a first function switching contactor contact 12a is closed, and when the coil 7 and the inverter 5 are used to charge the DC power supply 3, a second function switching contactor contact 12b is closed. In addition, the connection destination of the DC power supply 3 is also switched by the main contactor 11. When the coil 7 and the inverter 5 are used to drive the wheels, a first main contactor contact 11a is closed, and when the coil 7 and the inverter 5 are used to charge the DC power supply 3, a second main contactor contact 11b is closed.

[0029] However, in such a configuration in which the external AC power supply 4 and the DC power supply 3 are not electrically independent from each other, a relatively high leakage current from the external AC power supply 4 may flow to the common ground. Since a user or the like may be present near the vehicle during charging of the DC power supply 3, it is preferable to take such leakage current into consideration. In addition, in a configuration in which the external AC power supply 4 and the DC power supply 3 are not electrically independent from each other, when a short circuit failure or the like occurs in the external AC power supply 4, a large short circuit current may flow to the DC power supply 3 and the in-vehicle device connected to the DC power supply 3. The in-vehicle charging device 10 of this embodiment, which is configured using the coil 7 and inverter 5 of the in-vehicle rotating electric machine 70 like the charging device 10X, is configured to have higher safety than the charging device 10X and to suppress an increase in system costs.

[0030] The circuit block diagram of FIG. 2 shows a first example of the vehicle-mounted charging device 10 of this embodiment. As shown in FIG. 2, the vehicle-mounted charging device 10 is mounted on a vehicle equipped with a rotating electric machine 70 having coils 7 of multiple phases connected to each other at a neutral point 7N, an inverter 5 that converts power between direct current and multiple phase alternating current, and a direct current power source 3 connected to the rotating electric machine 70 via the inverter 5, and charges the direct current power source 3 with power supplied from an external alternating current power source 4. The vehicle-mounted charging device 10 includes a first circuit 1 that converts power between the AC power on the side of the external alternating current power source 4 and a first DC power, and a second circuit 2 that generates a second DC power from the first DC power to charge the DC power source 3. As shown in FIG. 2, 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.

[0031] The first circuit 1 is configured with an AC / DC converter including an input inductor Li arranged on the side of an external AC power source 4 and a full-bridge active rectifier (full-bridge 1c) having a power factor correction function, similar to the conventional charging device 10X. Also, similar to the charging device 10X, the input inductor Li is configured with a plurality of coils 7, and one of the two arms (first arm 1a and second arm 1b) of the full-bridge active rectifier (here, the first arm 1a) is configured with an inverter 5.

[0032] Unlike the conventional charging device 10X, the second circuit 2 is configured to include a dual active bridge circuit including a transformer T having a primary coil T1 and a secondary coil T2, a primary bridge circuit 21 connected to the first circuit 1 and the primary coil T1, and a secondary bridge circuit 22 connected to a DC power source 3 and the secondary coil T2. In addition, an output capacitor Co is disposed between the second circuit 2 and the DC power source 3.

[0033] By providing the second circuit 2 with the transformer T, the DC power supply 3 and the external AC power supply 4 are insulated from each other. This makes it easier to ensure the safety of the user against leakage current from the external AC power supply 4. In addition, when a short circuit or other fault occurs in the external AC power supply 4, it is possible to reduce the possibility that a large short-circuit current will flow to the DC power supply 3 and the in-vehicle device connected to the DC power supply 3. Here, the in-vehicle device connected to the DC power supply 3 includes, in addition to the rotating electric machine 70, a voltage conversion circuit 33 that supplies power to the low-voltage DC power supply 30, a compressor of the in-vehicle air conditioner, an electric oil pump, and the like.

[0034] 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. 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 DC power source 3, and functions as a dual active bridge DC / DC DAB Boost Converter from the DC power source 3 to the first circuit 1. The first circuit 1 also includes a full bridge 1c, 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 DC power source 3 can be used as an emergency power source.

[0035] As described above, the in-vehicle charging device 10 is configured to share the rotating electric machine 70 (coil 7) and the inverter 5. The switching of functions between when the coil 7 and the inverter 5 are used to drive the rotating electric machine 70 and when they are used as the in-vehicle charging device 10 is controlled by a contactor. As shown in Fig. 2, a main contactor 11, a grid contactor 13, a positive function switching contactor 12, a negative function switching contactor 14, a positive sub-contactor 15, and a negative sub-contactor 16 are provided.

[0036] The main contactor 11 is a contactor that can make and break the electrical connection between the drive system circuitry (e.g., inverter 5) of the rotating electric machine 70 and the on-board charging device 10, and the DC power source 3. When the main contactor 11 is closed, the drive system circuitry (e.g., inverter 5) of the rotating electric machine 70 and the on-board charging device 10 are electrically connected to the DC power source 3. When the main contactor 11 is open, the electrical connection between the drive system circuitry (e.g., inverter 5) of the rotating electric machine 70 and the on-board charging device 10, and the DC power source 3 is cut off.

[0037] The grid contactor 13 is a contactor that can make and break an electrical connection between the external AC power supply 4 and the on-board charging device 10. When the grid contactor 13 is closed, the external AC power supply 4 and the on-board charging device 10 are electrically connected. When the grid contactor 13 is open, the electrical connection between the external AC power supply 4 and the on-board charging device 10 is cut off.

[0038] The positive function switching contactor 12 and the negative function switching contactor 14 are contactors that selectively switch the inverter 5 between a function of driving the rotating electric machine 70 and a function as the in-vehicle charging device 10. The positive function switching contactor 12 and the negative function switching contactor 14 each have a first contact (12a, 14a) and a second contact (12b, 14b), and the two first contacts are controlled to the same state (closed or open), and the two second contacts are controlled to the same state (closed or open). That is, when the coil 7 and the inverter 5 are used to drive the rotating electric machine 70, the positive function switching contactor first contact 12a and the negative function switching contactor first contact 14a are closed. When the coil 7 and the inverter 5 are used in the vehicle-mounted charging device 10, the positive function switching contactor second contact 12b and the negative function switching contactor second contact 14b are closed.

[0039] The positive sub-contactor 15 and the negative sub-contactor 16 are contactors capable of electrically connecting or disconnecting the DC power source 3 and the in-vehicle charging device 10 (particularly the secondary bridge circuit 22 of the second circuit 2). The positive sub-contactor 15 and the negative sub-contactor 16 are controlled to be open or closed so as to be in the same state. When the positive sub-contactor 15 and the negative sub-contactor 16 are both closed, the DC power source 3 and the in-vehicle charging device 10 (secondary bridge circuit 22) are electrically connected. When the positive sub-contactor 15 and the negative sub-contactor 16 are both open, the electrical connection between the DC power source 3 and the in-vehicle charging device 10 (secondary bridge circuit 22) is cut off. Note that since it is possible to control the secondary bridge circuit 22 by a switching element so that no current flows toward the primary bridge circuit 21, the positive sub-contactor 15 and the negative sub-contactor 16 can be omitted.

[0040] These contactors are controlled to the states shown in Table 1 below when the coil 7 and the inverter 5 are used to drive the rotating electric machine 70 (operation mode (MODE): TRACTION), when the coil 7 and the inverter 5 are used as the in-vehicle charging device 10 (operation mode: OBC), etc. In the table, "Contactor" indicates the contactor described above, and the numbers correspond to the symbols indicating the contactors in the figure. Incidentally, "operation mode: OFF" is a state in which the vehicle is stopped (parked) and the DC power source 3 is not being charged. In addition, in the table, "close" indicates "closed", and "open" indicates "open". Incidentally, the in-vehicle charging device 10 of this embodiment is capable of bidirectional power conversion in the direction of generating the second DC power from the AC power and in the direction of generating the AC power from the second DC power, as described above. Since the states of the contactors are similar, the operation mode is included in "OBC".

[0041] [Table 1]

[0042] Incidentally, the rotating electric machine 70 is designed to have a high power density, and the coil 7 may have a small inductance as the input inductor Li of the AC-DC converter. For this reason, the peak value of the pulsation of the harmonic current of the system current of the external AC power source 4 tends to become large during AC-DC conversion. In order to suppress this, it is preferable to increase the control frequency of the inverter 5 constituting the first circuit 1. Alternatively, in order to reduce the pulsation on the side of the second circuit 2, the control frequency of the dual active bridge circuit of the DC-DC converter may be increased.

[0043] However, when the control frequency is increased, the control period (operating frequency) of the control device 80 that controls the inverter 5 and the DC-DC converter must also be shortened, and the cost of the processor such as a microcomputer that is the core of the control device 80 may increase. In addition, switching at a high frequency associated with a fast control period increases the loss in the switching elements of the inverter 5 and the dual active bridge circuit of the second circuit 2, leading to a decrease in the efficiency of the vehicle-mounted charging device 10. For this reason, it is also preferable to add an additional inductor La between the external AC power source 4 and the neutral point 7N of the coil 7, as in the second example of the vehicle-mounted charging device 10 illustrated in FIG. 3. That is, it is preferable that the first circuit 1 further includes an additional inductor La having an inductance larger than the inductance of the multiple coils 7 between the external AC power source 4 and the input inductor Li.

[0044] As described above, the rotating electric machine 70 that serves as the driving force source for the wheels is designed to have a high power density, and the coil 7 has a small inductance as an inductor of an AC-DC converter. The harmonic current of the system current of the external AC power source 4 is superimposed as pulsation on the first DC power converted from AC to DC, and the peak value of the pulsation tends to be large. By providing the additional inductor La, the inductance required for the AC-DC converter can be ensured, and the pulsation can be prevented from becoming large.

[0045] The configuration is the same as that of the in-vehicle charging device 10 of the first example except for the additional inductor La, so a detailed description of the in-vehicle charging device 10 of the second example will be omitted.

[0046] As described above with reference to Fig. 1, the vehicle includes a DC power source 3 having a rated power supply voltage of 200 to 800 volts, and a low-voltage DC power source 30 having a rated voltage lower than that of the DC power source 3. As shown in Fig. 1, the low-voltage DC power source 30 can be charged with the power of the DC power source 3 via a voltage conversion circuit 33 having a DC-DC converter or the like as its core. However, in this case, energy for running the vehicle is consumed for charging the low-voltage DC power source 30. Therefore, for example, when the DC power source 3 is charged with power supplied from the external AC power source 4, it is preferable that the low-voltage DC power source 30 is also charged with power supplied from the external AC power source 4.

[0047] A third example shown in Fig. 4 and a fourth example shown in Fig. 5 show such configurations of the vehicle-mounted charging device 10. The third example of the vehicle-mounted charging device 10 shown in Fig. 4 is a configuration in which the second circuit 2 of the vehicle-mounted charging device 10 of the first example shown in Fig. 2 is expanded to a multi-port, and the fourth example of the vehicle-mounted charging device 10 shown in Fig. 5 is a configuration in which the second circuit 2 of the vehicle-mounted charging device 10 of the second example shown in Fig. 3 is expanded to a multi-port.

[0048] As shown in Fig. 4 and Fig. 5, in the second circuit 2 of the in-vehicle charging device 10 of the third and fourth examples, the secondary coil T2 includes a secondary first coil T21 and a secondary second coil T22. The secondary bridge circuit 22 includes a triple active bridge circuit including a secondary first bridge circuit 221 that generates a second DC power for charging the DC power source 3, and a secondary second bridge circuit 222 that generates a third DC power for charging the low-voltage DC power source 30 from the first DC power. The secondary first bridge circuit 221 is connected to the DC power source 3 and the secondary first coil T21, and the secondary second bridge circuit 222 is connected to the low-voltage DC power source 30 and the secondary second coil T22. In addition, two output capacitors Co are provided: a first output capacitor Co1 arranged between the DC power supply 3 and the secondary side first bridge circuit 221, and a second output capacitor Co2 arranged between the low-voltage DC power supply 30 and the secondary side second bridge circuit 222.

[0049] When the low-voltage DC power supply 30 is mounted on the vehicle, it is necessary to charge the low-voltage DC power supply 30 in addition to the DC power supply 3. When the low-voltage DC power supply 30 is charged by the power of the DC power supply 3, a DC-DC converter or the like is required between the DC power supply 3 and the low-voltage DC power supply 30. According to this configuration, by adding the secondary side second coil T22 and the secondary side second bridge circuit 222 to the vehicle-mounted charging device 10 for charging the DC power supply 3, it is possible to charge the low-voltage DC power supply 30 without providing a separate DC-DC converter. In addition, it is preferable that the DC power supply 3 and the low-voltage DC power supply 30 are insulated, but by providing the transformer T in the second circuit 2, it is possible to ensure insulation between the DC power supply 3 and the low-voltage DC power supply 30, and further insulation between the external AC power supply 4 and the low-voltage DC power supply 30.

[0050] In addition, in common to the first to fourth examples, in the in-vehicle charging device 10 of this embodiment, the coil 7 and the inverter 5 are used in the first circuit 1 that converts the AC power supplied from the external AC power source 4 into the first DC power. That is, the second circuit 2 is configured independently from the drive system circuit of the rotating electric machine 70. Therefore, even when the rotating electric machine 70 is being driven, the second circuit 2 can be operated. That is, by operating the second circuit 2, it is possible to supply power from the DC power source 3 to the low-voltage DC power source 30. Therefore, the voltage conversion circuit 33 described above with reference to FIG. 1 can be configured by the secondary coil T2 (the secondary coil T21 and the secondary coil T22), the secondary bridge circuit 221, and the secondary bridge circuit 222.

[0051] The on-board charging device 10 of the third and fourth examples further includes a low-voltage DC power supply connection contactor 17 and a charging circuit connection contactor 18 in addition to a main contactor 11, a grid contactor 13, a positive side function switching contactor 12, a negative side function switching contactor 14, a positive side sub-contactor 15, and a negative side sub-contactor 16.

[0052] The low-voltage DC power supply connection contactor 17 is a contactor that can make and break the electrical connection between the low-voltage DC power supply 30 and the in-vehicle charging device 10. When the low-voltage DC power supply connection contactor 17 is closed, the low-voltage DC power supply 30 and the in-vehicle charging device 10 are electrically connected. When the low-voltage DC power supply connection contactor 17 is open, the electrical connection between the low-voltage DC power supply 30 and the in-vehicle charging device 10 is cut off.

[0053] The charging circuit connection contactor 18 is a contactor that can make and break the electrical connection between the low-voltage DC power supply 30 and the secondary-side second bridge circuit 222 of the in-vehicle charging device 10. When the charging circuit connection contactor 18 is closed, the low-voltage DC power supply 30 and the secondary-side second bridge circuit 222 are electrically connected. When the charging circuit connection contactor 18 is open, the electrical connection between the low-voltage DC power supply 30 and the secondary-side second bridge circuit 222 is cut off. Note that since it is possible to control the switching element of the secondary-side second bridge circuit 222 so that no current flows toward the primary-side bridge circuit 21 and the secondary-side first bridge circuit 221, the charging circuit connection contactor 18 can be omitted.

[0054] These contactors are controlled to the states shown in Table 2 below when the coil 7 and inverter 5 are used to drive the rotating electric machine 70 (operation mode (MODE): TRACTION), when the coil 7 and inverter 5 are used as the in-vehicle charging device 10 (operation mode: OBC), etc. As in Table 1, "Contactor" in the table indicates the above-mentioned contactor, and the numbers correspond to the symbols indicating the contactors in the figure. Furthermore, the in-vehicle charging device 10 of the third and fourth examples can also charge the low-voltage DC power source 30 while the coil 7 and inverter 5 are used to drive the rotating electric machine 70 (operation mode: TRACTION & CHARGE). "Operation mode: OFF", "close" and "open" in the table are as described above for Table 1.

[0055] [Table 2]

[0056] As described above, the second circuit 2 functions as a DC-DC step-down converter from the first circuit 1 to the DC power source 3, and functions as a DC-DC step-up converter from the DC power source 3 to the first circuit 1. The first circuit 1 can also function as a bidirectional power converter having a function of converting DC to AC, in addition to the function of converting AC to DC.

[0057] Common to the first to fourth 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) and power conversion from DC (second DC power) to AC. Specifically, the vehicle-mounted charging device 10 of the first and second examples can be said to be configured as follows. When the vehicle-mounted charging device 10 charges the DC power source 3 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 dual active bridge DC / DC DAB Buck converter. When the in-vehicle charging device 10 functions as an emergency AC power supply that outputs AC power using the power stored in the DC power supply 3, the second circuit 2 functions as a dual active bridge DC-DC boost converter (DC / DC DAB Boost Converter) and the first circuit 1 functions as a single power factor DC-AC buck converter (DC / AC Buck Converter UPF).

[0058] Moreover, the on-vehicle charging device 10 of the third and fourth examples can be said to be configured as follows. When the on-vehicle charging device 10 charges the DC power source 3 by the external AC power source 4, the first circuit 1 functions as a single power factor AC / DC boost converter (AC / DC Boost Converter UPF), and the second circuit 2 functions as a dual active bridge multi-port DC / DC step-down converter (DC / DC Multi Port DAB Buck Converter). Alternatively, the second circuit 2 can be said to function as a triple active bridge DC / DC TAB (Triple Active Bridge) Buck Converter. When the on-vehicle charging device 10 functions as an emergency AC power source that outputs AC power using power stored in the DC power source 3, the second circuit 2 functions as a dual active bridge multi-port DC / DC step-down converter (DC / DC Multi Port DAB Boost Converter), and the first circuit 1 functions as a single power factor DC / AC Buck Converter UPF. The second circuit 2 can be said to function as a triple active bridge DC / DC TAB Boost Converter.

[0059] As described above by way of example of various embodiments, according to this embodiment, an on-board charging device that utilizes the coil and inverter of an on-board rotating electric machine to charge an on-board DC power supply with power from an external AC power supply can be configured with higher safety while suppressing increases in system costs. [Explanation of symbols]

[0060] 1: first circuit, 1a: first arm (one of the two arms of a full-bridge active rectifier), 1b: second arm (one of the two arms of a full-bridge active rectifier), 1c: full bridge, 2: second circuit, 3: DC power supply, 4: external AC power supply, 5: inverter, 7: coil, 7N: neutral point, 10: on-board charging device, 21: primary side bridge circuit, 22: secondary side bridge circuit, 30: low-voltage DC power supply, 70: rotating machine, 221: secondary side first bridge circuit, 222: secondary side second bridge circuit, La: additional inductor, Li: input inductor, T: transformer, T1: primary side coil, T2: secondary side coil, T21: secondary side first coil, T22: secondary side second coil

Claims

1. An on-board charging device is mounted on a vehicle including a rotating electric machine having coils of multiple phases connected to each other at a neutral point, an inverter that converts power between direct current and multiple phase alternating current, and a direct current power source that is connected to the rotating electric machine via the inverter, and charges the direct current power source with power supplied from an external alternating current power source, a first circuit that converts power between AC power on the side of the external AC power supply and a first DC power; a second circuit that generates a second DC power from the first DC power to charge the DC power supply; The first circuit is an input inductor disposed on the side of the external AC power supply; A full-bridge active rectifier having a power factor correction function; and an AC-DC converter comprising the same. The second circuit is a transformer having a primary coil and a secondary coil; a primary side bridge circuit connected to the first circuit and the primary side coil; a secondary bridge circuit connected to the DC power supply and the secondary coil; the input inductor is configured using a plurality of the coils, An on-board charging device, wherein one of the two arms of the full-bridge active rectifier is configured using the inverter.

2. The on-board charging device according to claim 1 , wherein the first circuit further comprises an additional inductor between the external AC power supply and the input inductor, the additional inductor having an inductance larger than an inductance of the plurality of coils.

3. the vehicle includes a low-voltage DC power supply having a rated voltage lower than that of the DC power supply, The second circuit is The secondary coil includes a first secondary coil and a second secondary coil, the secondary-side bridge circuit comprises a triple active bridge circuit including a secondary-side first bridge circuit that generates the second DC power, and a secondary-side second bridge circuit that generates a third DC power from the first DC power and charges the low-voltage DC power supply; the secondary side first bridge circuit is connected to the DC power supply and the secondary side first coil, The in-vehicle charging device according to claim 1 , wherein the secondary side second bridge circuit is connected to the low-voltage DC power source and the secondary side second coil.

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