On-board charging device

Abstract

The on-board charging system, which charges the on-board DC power supply using power from an external AC power source, is configured to reduce system costs. [Solution] The on-board charging device 10, which charges a DC power supply with power supplied from an external AC power supply 4, includes an AC-DC converter 1 connected to the primary coil T1 of a transformer and equipped with a primary bridge circuit 11 composed of bidirectional switching elements 11S. The on-board charging device 10 is configured to selectively connect a three-phase AC power supply 4t and a single-phase AC power supply 4s as the external AC power supply 4, and the primary bridge circuit 11 is configured to switch between a three-legged full-bridge circuit 13 when the external AC power supply 4 is a three-phase AC power supply 4t, and a two-legged full-bridge circuit 14 and an active decoupling circuit 15 when the external AC power supply 4 is a single-phase AC power supply 4s.

Description

Technical Field

[0001] The present invention relates to an in-vehicle charging device.

Background Art

[0002] Japanese Patent Publication No. 2022-503713 discloses an in-vehicle charging device (onboard charger) that charges a DC power source mounted on a vehicle equipped with a rotating electric machine as a driving power source for wheels, such as a battery electric vehicle (BEV) or a plug-in hybrid electric vehicle (PHEV), while the device is mounted on the vehicle. (Hereinafter, the reference numerals in parentheses in the background art are those of the said document.) FIG. 1 of this document shows a schematic block diagram of an in-vehicle charging device that receives power supply from an external AC power source (110) and charges an in-vehicle DC power source (140). This in-vehicle charging device includes an AC-DC converter (120) that converts AC power supplied from an external AC power source into DC power, and a DC-DC converter (130) that reduces the pulsation component included in the converted DC power, transforms it, and supplies it to the DC power source.

[0003] Figure 7 illustrates one form of such an on-board charging device. The AC-DC converter 1 can be configured with a primary bridge circuit 11. The DC-DC converter 2 can be configured as a dual active bridge (DAB) circuit comprising a transformer T, a full bridge circuit 2a located on the primary side of the transformer T, and a full bridge circuit 2b located on the secondary side of the transformer T. The presence of the transformer T ensures isolation between the external AC power supply 4 and the DC power supply 3. The AC-DC converter 1 with the primary bridge circuit 11 also functions as a power factor correction (PFC) circuit to improve the power factor of the DC power converted from AC power. The primary bridge circuit 11 is also switched to suppress the pulsation of the second harmonic of the frequency of the AC power. The DC-DC converter 2 further reduces the pulsation component of the DC power by the dual active bridge circuit and provides the charging current to the DC power supply 3. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Special Publication No. 2022-503713 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the configuration illustrated in Figure 7, the on-board charging device is equipped with three full-bridge circuits, requiring a large number of switching elements for the entire on-board charging device, which increases system costs. In recent years, the performance of rechargeable secondary batteries has improved significantly, and it may be possible to tolerate charging currents with larger amplitude pulsations than before during charging. Therefore, the need to suppress pulsations that occur during power conversion from AC to DC may decrease compared to the present. In addition, there are several methods for charging the DC power supply of electric vehicles such as BEVs and PHEVs, including using single-phase AC power in a home, using three-phase AC power in a dedicated facility, and using DC power in a dedicated facility. It is preferable for the vehicle side to support these multiple methods. However, individually installing charging devices for each method leads to increased system costs.

[0006] In light of the above background, it is desirable to configure an on-board charging device that charges the on-board DC power supply using power from an external AC power source while keeping system costs down. [Means for solving the problem]

[0007] In view of the above, the on-board charging device is an on-board charging device that charges at least a first DC power supply with power supplied from an external AC power supply, and comprises an AC / DC converter that converts power between the AC power on the external AC power supply side and the first DC power on the first DC power supply side, the AC / DC converter comprises an active bridge circuit comprising a transformer having a primary coil and a secondary coil, a primary bridge circuit connected to the primary coil, and a secondary bridge circuit connected to the secondary coil, the primary bridge circuit is composed of bidirectional switching elements, and is configured to selectively connect a three-phase AC power supply and a single-phase AC power supply as the external AC power supply, and the primary bridge circuit is configured to switch its function according to the type of external AC power supply between a three-legged full bridge circuit when the external AC power supply is the three-phase AC power supply, and a two-legged full bridge circuit and an active decoupling circuit when the external AC power supply is the single-phase AC power supply.

[0008] This configuration allows for the charging of the first DC power supply while maintaining isolation between the external AC power supply and the first DC power supply, without requiring a separate DC-DC converter after AC-DC conversion, thus reducing the number of switching elements and enabling a smaller on-board charging system. Furthermore, the bidirectional switching elements constituting the primary bridge circuit easily enable soft switching with zero-current switching, which reduces the current flowing through the switching elements during switching. Consequently, losses in the on-board charging system are easily reduced, and system costs are lowered. Moreover, since three-phase AC power supplies and single-phase AC power supplies can be selectively connected as the external AC power supply, it can flexibly accommodate various power supply specifications at the charging location. In addition, the circuits corresponding to three-phase AC power supplies and single-phase AC power supplies are switched using a common primary bridge circuit, thus suppressing an increase in system costs. Thus, this configuration allows for the construction of an on-board charging system that charges the on-board DC power supply using power from an external AC power supply, while keeping system costs down.

[0009] Further features and advantages of the on-board charging device will become clear from the following description of exemplary and non-limiting embodiments, which will be illustrated with reference to the drawings. [Brief explanation of the drawing]

[0010] [Figure 1] Circuit block diagram showing an example configuration of an in-vehicle charging device. [Figure 2] Diagram illustrating the function of the primary bridge circuit when a three-phase AC power supply is connected and when a single-phase AC power supply is connected. [Figure 3] A diagram showing an example of a rotating electric machine control system. [Figure 4] Diagram showing another example of a rotating electric machine control system. [Figure 5] Circuit block diagram showing an example configuration of an in-vehicle charging device using a single DC power supply. [Figure 6]Circuit block diagram showing other configuration examples of an in-vehicle charging device. [Figure 7] This diagram shows an example of a conventional in-vehicle charging device that uses a single DC power source. [Figure 8] This diagram shows an example of a conventional in-vehicle charging device that uses two DC power sources. [Modes for carrying out the invention]

[0011] The following describes an embodiment of the onboard charging device with reference to the drawings. The onboard charging device 10 is a device that charges a DC power source (at least the first DC power source 3) with power supplied from an external AC power source 4 while the DC power source (at least the first DC power source 3) is mounted on the vehicle, and is a device known as an onboard charger. The first DC power source 3 supplies power to a rotating electric machine (traction motor) that is the driving force source for the wheels in an electric vehicle (BEV: Battery Electric Vehicle) or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid EV).

[0012] This rotating electric machine (corresponding to the first rotating electric machine 7M described later: see Figures 3 and 4) functions as a traction motor and can also function as a generator to charge the DC power supply. For example, in a PHEV, it is possible to supply mechanical energy to the rotating electric machine using power from an internal combustion engine or other source to generate electricity, but opportunities for power generation are infrequent and the DC power supply may not be sufficiently charged. Also, in a BEV that is only equipped with a rotating electric machine as a driving force source, power generation is limited to mechanical energy from the wheels during coasting, etc., and the DC power supply is often not sufficiently charged. Furthermore, even in a PHEV, it is sometimes more energy efficient to supply power from an external source than to have the rotating electric machine generate power. For this reason, an on-board charging device 10 is provided that charges the DC power supply, which is installed in the vehicle, with power supplied from an external power source.

[0013] Here, as shown in Figure 1, the vehicle charging device 10 will be described as an example in which the vehicle charging device 10 charges a first DC power supply 3 and a second DC power supply 30, which is electrically isolated from the first DC power supply 3, using power supplied from an external AC power supply 4. However, the vehicle charging device 10 may be a device that charges only one DC power supply (in this case, the first DC power supply 3), as illustrated in Figure 5. Furthermore, the vehicle charging device 10 is a bidirectional power converter and can, for example, convert DC power supplied from the first DC power supply 3 or the second DC power supply 30 into AC power at commercial frequency and output it. Hereafter, when "this embodiment" is referred to in this specification, unless otherwise specified, it refers to both the vehicle charging device 10 that charges only the first DC power supply 3 and the vehicle charging device 10 that charges both the first DC power supply 3 and the second DC power supply 30.

[0014] The first DC power supply 3 and the second DC power supply 30 are electrically independent DC power supplies that are isolated from each other. Their rated voltages may be different or the same, and their storage capacities may be the same or different. Figure 3 shows an example of a rotating electric machine drive system in which the first DC power supply 3 and the second DC power supply 30 are connected to different rotating electric machines (first rotating electric machine 7M, second rotating electric machine 8M).

[0015] For example, the first rotating electric motor 7M is a traction motor, and the second rotating electric motor 8M is a drive motor for an oil pump or a drive motor for an air conditioner compressor. In this case, it is preferable that the first DC power supply 3 and the second DC power supply 30 are DC power supplies with different rated voltages and storage capacities. For example, the rated voltage of the first DC power supply 3 is about 200 to 800 volts (preferably a 400-volt or 800-volt battery pack), and the rated voltage of the second DC power supply 30 is about 12 to 200 volts (preferably a 12-volt or 42-volt battery pack).

[0016] Also, for example, in a four-wheel drive vehicle, the first rotating electric machine 7M and the second rotating electric machine 8M may be traction motors for the front wheels and the rear wheels, respectively. In this case, it is preferable that the first DC power source 3 and the second DC power source 30 are DC power sources having the same rated voltage and storage capacity. For example, the rated voltage of the first DC power source 3 and the second DC power source 30 is about 200 to 800 volts.

[0017] FIG. 3 shows a star connection form in which the stator coils (7, 8) are connected at the neutral points (7N, 8N). As shown in FIG. 4, in an open-wound traction motor in which the stator coils are independent of each other without being connected to each other by a star connection (see FIG. 3) or a delta connection, the first DC power source 3 and the second DC power source 30 are connected to both ends of the stator coil (first stator coil 7), respectively. Also in this case, it is preferable that the first DC power source 3 and the second DC power source 30 are DC power sources having the same electrical specifications (rated voltage and storage capacity). In an open-wound traction motor, since the combined voltage of the first DC power source 3 and the second DC power source 30 can be applied to the stator coil, the rated voltage of the first DC power source 3 and the second DC power source 30 is preferably about 200 to 400 volts.

[0018] The first DC power source 3 and the second DC power source 30 are composed of, for example, a rechargeable secondary battery (battery) such as a lithium-ion battery, or an electric double layer capacitor. Note that a form in which the second DC power source 30 is a DC power source having a rated voltage of about 12 volts to 24 volts, which is also mounted on a conventional vehicle having an internal combustion engine as a driving power source and supplies power to electrical components such as the vehicle's ECU (Electric Control Unit), lighting device, and audio device, is not excluded. In this case, the second DC power source 30 may be a lead storage battery.

[0019] The rotating electric machine drive system includes a first control device 80 that controls the first rotating electric machine 7M, and a second control device 88 that controls the second rotating electric machine 8M. Based on the target torque (torque command) for the first rotating electric machine 7M and the second rotating electric machine 8M, which is provided as a request signal from a higher-level control device such as a vehicle control device 90, the system performs current feedback control to drive and control the first rotating electric machine 7M and the second rotating electric machine 8M. The actual current flowing through the stator coil (first stator coil 7) of the first rotating electric machine 7M is detected by a first motor current sensor 81, and the magnetic pole position (electric angle) and rotor rotation speed (angular velocity) of the rotor of the first rotating electric machine 7M at each point in time are detected by a first rotation sensor 82, such as a resolver or an inductive position sensor. The first control device 80 acquires the detection results and drives and controls the first rotating electric machine 7M via the first inverter 5. The actual current flowing through the stator coil (second stator coil 8) of the second rotating electric machine 8M is detected by the second motor current sensor 83, and the magnetic pole position (electric angle) and rotor rotation speed (angular velocity) of the rotor of the second rotating electric machine 8M at each point in time are detected by the second rotation sensor 84. The second control device 88 acquires these detection results and drives and controls the second rotating electric machine 8M via the second inverter 50.

[0020] The first inverter 5 is connected to the first rotating electric machine 7M and the first DC power supply 3, and converts power between AC (here, three-phase) and DC. The second inverter 50 is connected to the second rotating electric machine 8M and the second DC power supply 30, and converts power between AC (here, three-phase) and DC. On the DC side of the first inverter 5, a first smoothing capacitor 6 for smoothing the DC voltage is provided. On the DC side of the second inverter 50, a second smoothing capacitor 60 for smoothing the DC voltage is provided. The first inverter 5 and the first DC power supply 3 are electrically connected in a state where the first main contactor M1 is closed, and the electrical connection is interrupted in a state where the first main contactor M1 is opened. The second inverter 50 and the second DC power supply 30 are electrically connected in a state where the second main contactor M2 is closed, and the electrical connection is interrupted in a state where the second main contactor M2 is opened. The first main contactor M1 and the second main contactor M2 are, for example, mechanical relays.

[0021] The first inverter 5 and the second inverter 50 each include a U-phase leg, a V-phase leg, and a W-phase leg as a plurality of phases of legs. Each leg is formed by serially connecting an upper-side switching element (in the first inverter 5, "5U"; in the second inverter 50, "50U") arranged on the positive electrode side and a lower-side switching element (in the first inverter 5, "5L"; in the second inverter 50, "50L") arranged on the negative electrode side. The midpoint of each leg, that is, the connection point between the upper-side switching element and the lower-side switching element, is connected to the stator coil (the first stator coil 7, the second stator coil 8) of each rotating electric machine. Specifically, the midpoint of the U-phase leg is connected to the U-phase coil (7u, 8u), the midpoint of the V-phase leg is connected to the V-phase coil (7v, 8v), and the midpoint of the W-phase leg is connected to the W-phase coil (7w, 8w).

[0022] In the open-winding type rotating electric machine drive system shown in Figure 4, the midpoints of the same phase legs of the first inverter 5 and the second inverter 50 are connected via the stator coil (first stator coil 7) of the rotating electric machine. Specifically, the midpoint of the U-phase leg of the first inverter 5 and the midpoint of the U-phase leg of the second inverter 50 are connected via a U-phase coil (7u), the midpoint of the V-phase leg of the first inverter 5 and the midpoint of the V-phase leg of the second inverter 50 are connected via a V-phase coil (7u), and the midpoint of the W-leg of the first inverter 5 and the midpoint of the W-phase leg of the second inverter 50 are connected via a W-phase coil (7w).

[0023] As shown in Figures 1 and 5, the on-board charging device 10 of this embodiment includes an AC / DC converter 1 that converts power between AC power from an external AC power source 4 and a first DC power source from at least a first DC power source 3. The AC / DC converter 1 includes a transformer T having a primary coil T1 and a secondary coil T2. A primary circuit 1a, including the primary coil T1, is configured on the primary side of the transformer T. A secondary circuit 1b, including the secondary coil T2, is configured on the secondary side of the transformer T. A primary bridge circuit 11 is connected to the primary coil T1, and a secondary bridge circuit 12 is connected to the secondary coil T2, thereby configuring an active bridge circuit.

[0024] As shown in Figure 1, in a configuration that includes an AC / DC converter 1 that converts power between the AC power on the external AC power source 4 and the first DC power on the first DC power source 3 and the second DC power on the second DC power source 30, the secondary coil T2 includes a secondary first coil T21 and a secondary second coil T22 (the secondary first coil T21 can also be called the "secondary coil" and the secondary second coil T22 can be called the "tertiary coil"). The secondary bridge circuit 12 is a triple active bridge circuit that includes a secondary first bridge circuit 121 connected to the secondary first coil T21 and a secondary second bridge circuit 122 connected to the secondary second coil T22. As shown in Figure 5, in a configuration that charges a single DC power source, it is a dual active bridge circuit that includes a primary bridge circuit 11 and a secondary bridge circuit 12 separated by a transformer T.

[0025] On the output side (DC side) of the secondary circuit (secondary bridge circuit 12), DC link capacitors (first DC link capacitor Cdc1, second DC link capacitor Cdc2) are arranged to smooth the DC voltage. The voltage output from the AC-DC converter 1 may have pulsations of harmonic components of the frequency of the external AC power supply 4 superimposed on it, but the first DC link capacitor Cdc1 and the second DC link capacitor Cdc2 reduce the amplitude of these pulsations.

[0026] Furthermore, the secondary bridge circuit 12 is connected to DC power supplies (first DC power supply 3, second DC power supply 30) via charging contactors (first charging contactor Mc1, second charging contactor Mc2). When the first charging contactor Mc1 is closed, the on-board charging device 10 and the first DC power supply 3 are electrically connected, and when the first charging contactor Mc1 is open, the electrical connection between the on-board charging device 10 and the first DC power supply 3 is interrupted. Similarly, when the second charging contactor Mc2 is closed, the on-board charging device 10 and the second DC power supply 30 are electrically connected, and when the second charging contactor Mc2 is open, the electrical connection between the on-board charging device 10 and the second DC power supply 30 is interrupted. The first charging contactor Mc1 and the second charging contactor Mc2 are, for example, mechanical relays.

[0027] The primary bridge circuit 11 is composed of bidirectional switching elements 11S. As shown in Figure 1, the equivalent circuit of the bidirectional switching element 11S is a configuration in which switching elements, each having a transistor section and a diode section connected in parallel, are connected in series with reverse polarity (sources together, drains together, emitters together, or collectors together). A "bidirectional switching element" is a semiconductor element in which the above-described equivalent circuit is configured.

[0028] A "bidirectional switching element" is an element that allows current to flow bidirectionally through the semiconductor element when both transistor sections are ON, and can block current flow in either direction when both transistor sections are OFF. When either of the two transistor sections is ON, the direction of current flow and the direction of current blocking are controlled according to the polarity of the diode section. By using a bidirectional switching element 11S, the primary bridge circuit 11 can be constructed with a small number of switching elements, making it easier to reduce costs. In addition, bidirectional switching elements make it easier to achieve soft switching accompanied by zero-current switching (ZCS), which reduces the current flowing through the switching element to zero during switching. Therefore, it is easier to reduce losses in the on-board charging device 10 and reduce system costs.

[0029] Figure 7 illustrates one configuration of a conventional on-board charging device targeting a single DC power source (referred to as a conventional first charging device 10X targeting a first DC power source 3). The conventional first charging device 10X comprises an AC-DC converter 1 and a DC-DC converter 2. The DC-DC converter 2 transforms the DC power converted by the AC-DC converter 1 while reducing the pulsating component contained in the DC power and supplies power to the first DC power source 3. The AC-DC converter 1 is configured with a primary-side bridge circuit 11 that functions as a power factor correction circuit. The DC-DC converter 2 is configured as a dual-active bridge circuit comprising a full-bridge circuit 2a located on the primary side of the transformer T and a full-bridge circuit 2b located on the secondary side of the transformer T. The conventional first charging device 10X comprises three full-bridge circuits (11, 2a, 2b), and many switching elements are used in the on-board charging device as a whole.

[0030] Figure 8 illustrates one configuration of a conventional on-board charging device that targets two DC power sources (referred to as a conventional second charging device 10Y that targets a first DC power source 3 and a second DC power source 30). Similar to the conventional first charging device 10X, the conventional second charging device 10Y also includes an AC-DC converter 1 and a DC-DC converter 2. The configuration of the AC-DC converter 1 of the conventional second charging device 10Y is the same as that of the conventional first charging device 10X. The DC-DC converter 2 of the conventional second charging device 10Y is configured as a triple active bridge circuit, comprising a full-bridge circuit 2a located on the primary side of the transformer T, and full-bridge circuits 2b and 2c located on the secondary side of the transformer T. The conventional second charging device 10Y has four full-bridge circuits (11, 2a, 2b, 2c) and requires even more switching elements as a whole on the on-board charging device.

[0031] Compared to these conventional charging devices, the in-vehicle charging device 10 of this embodiment can be configured with a smaller number of elements, making it easier to reduce system costs.

[0032] Furthermore, the on-board charging device 10 of this embodiment can be configured with only an AC-DC converter 1 equipped with a transformer T, without the need for a DC-DC converter. As will be described later with reference to Figures 7 to 9, it is not ruled out that the on-board charging device 10 may also be configured with a DC-DC converter 2, but configuring the on-board charging device 10 without the DC-DC converter 2 makes it easier to reduce system costs. In recent years, the performance of rechargeable secondary batteries has improved remarkably, and it may become possible to tolerate charging currents with larger amplitude pulsations than before during charging. In this case, the on-board charging device 10 of this embodiment, as illustrated in Figure 1, is useful.

[0033] Incidentally, there are several methods for charging electric vehicles such as BEVs and PHEVs using DC power, including single-phase AC power from a household (single-phase AC charging), three-phase AC power from a dedicated facility (three-phase AC charging), and DC power from a dedicated facility (DC charging). It is preferable for the vehicle to support multiple of these methods. However, installing separate charging devices for each method leads to increased system costs. DC charging has a configuration similar to a direct-drive type, and the circuit size of the on-board charging device 10 is smaller than that of AC charging. However, the circuit size of AC charging tends to be larger, as can be seen from the fact that an AC / DC converter 1 is required. In this embodiment, the circuit is configured to be switchable according to the type of external AC power source 4 so that the circuit can be shared between single-phase AC charging and three-phase AC charging.

[0034] As shown in Figure 2, the in-vehicle charging device 10 of this embodiment is configured to selectively connect to a three-phase AC power supply 4t and a single-phase AC power supply 4s as the external AC power supply 4. The primary bridge circuit 11 is configured to switch its function according to the type of external AC power supply 4, functioning as a three-leg full bridge circuit 13 when the external AC power supply 4 is a three-phase AC power supply 4t, and functioning as a two-leg full bridge circuit 14 and an active decoupling circuit 15 when the external AC power supply 4 is a single-phase AC power supply 4s.

[0035] As shown in Figure 1, the external AC power supply 4 is connected to the three input terminals (first input terminal N7, second input terminal N8, and third input terminal N9) of the on-board charging device 10 via a grid contactor S4. The three-phase AC power supply 4t is configured by connecting the negative terminals of three AC power supplies, each with a phase difference of 2π / 3, at the power supply neutral point 4N. The positive terminals of the three AC power supplies are connected to each of the three input terminals via the grid contactor S4. The grid contactor S4 also has three contacts, and the first input terminal N7 is connected to the external AC power supply 4 via the first grid contact 41, the second input terminal N8 via the second grid contact 42, and the third input terminal N9 via the third grid contact 43.

[0036] When the external AC power supply 4 is a single-phase AC power supply 4s, the single-phase AC power supply 4s is connected to, for example, the first input terminal N7 and the second input terminal N8 of the three input terminals via the grid contactor S4. The positive terminal of the single-phase AC power supply 4s is connected to the first input terminal N7 via the first grid contact 41, and the negative terminal of the single-phase AC power supply 4s is connected to the second input terminal N8 via the second grid contact 42. The third grid contact 43 is left open.

[0037] As shown in Figure 1, the primary bridge circuit 11 comprises a first leg G1, a second leg G2, and a third leg G3, which are connected between the primary positive electrode N4 and the primary negative electrode N5, respectively. The midpoint of the first leg G1 (the connection point of the two bidirectional switching elements 11S that constitute the leg) is referred to as the first node N1, the midpoint of the second leg G2 as the second node N2, and the midpoint of the third leg G3 as the third node N3.

[0038] As shown in Figure 1, an LC filter 1f is provided between the external AC power supply 4 and the primary bridge circuit 11. This filter 1f consists of three filter inductors Lf connected in series to the respective power lines connecting the external AC power supply 4 and the primary bridge circuit 11, and three filter capacitors Cf connected between the respective power lines. The three filter capacitors Cf are connected to each other at the capacitor neutral point N0.

[0039] The on-board charging device 10 includes a function-switching first contactor S1 and a function-switching second contactor S2. As described above, when the external AC power supply 4 is a single-phase AC power supply 4s, the external AC power supply 4 is not connected to the third input terminal N9. Therefore, the third capacitor Cf3 of the filter capacitor Cf, which is connected to the power line connecting the third input terminal N9 and the primary bridge circuit 11, can be disconnected by the function-switching first contactor S1. A storage capacitor Cs (fourth capacitor), which will be described later, can be connected to this power line via the function-switching second contactor S2.

[0040] The filter inductor Lf comprises a first inductor Lf1, a second inductor Lf2, and a third inductor Lf3. The first inductor Lf1 is connected between the first node N1, which is the midpoint of the first leg G1, and the first input terminal N7 on the side of the external AC power supply 4. The second inductor Lf2 is connected between the second node N2, which is the midpoint of the second leg G2, and the second input terminal N8 on the side of the external AC power supply 4. The third inductor Lf3 is connected between the third node N3, which is the midpoint of the third leg G3, and the third input terminal N9 on the side of the external AC power supply 4.

[0041] The filter capacitor Cf comprises a first capacitor Cf1, a second capacitor Cf2, and a third capacitor Cf3. The first capacitor Cf1 is connected between the first node N1, which is the midpoint of the first leg G1, and the capacitor neutral point N0. The second capacitor Cf2 is connected between the second node N2, which is the midpoint of the second leg G2, and the capacitor neutral point N0. The third capacitor Cf3 is connected between the third node N3, which is the midpoint of the third leg G3, and the capacitor neutral point N0 via a function-switching first contactor S1.

[0042] The storage capacitor Cs, acting as the fourth capacitor, is connected between the third input terminal N9 and the primary side negative electrode N5 via a functional switching second contactor S2. The storage capacitor Cs is a capacitor that constitutes the active decoupling circuit 15 and is used when the external AC power supply 4 is a single-phase AC power supply 4s. When the external AC power supply 4 is a three-phase AC power supply 4t, the storage capacitor Cs is disconnected.

[0043] When the external AC power supply 4 is a three-phase AC power supply 4t, as described above, each phase of the three-phase AC power supply 4t is connected to the first input terminal N7, the second input terminal N8, and the third input terminal N9, respectively, via the grid contactor S4. The first function-switching contactor S1 is closed, and the second function-switching contactor S2 is opened. That is, by closing the first function-switching contactor S1, the first capacitor Cf1, the second capacitor Cf2, and the third capacitor Cf3 are connected at the capacitor neutral point N0. Also, by opening the second function-switching contactor S2, the storage capacitor Cs is disconnected. This forms a three-legged full-bridge circuit 13.

[0044] When the external AC power supply 4 is a single-phase AC power supply 4s, as described above, the positive and negative poles of the single-phase AC power supply 4s are connected to the first input terminal N7 and the second input terminal N8, respectively, via the grid contactor S4. The function-switching first contactor S1 is opened, and the function-switching second contactor S2 is closed. That is, by opening the function-switching first contactor S1, the third capacitor Cf3 and the third leg G3 are disconnected from the capacitor neutral point N0, and a two-leg full-bridge circuit 14 is formed. Furthermore, by closing the function-switching second contactor S2, the storage capacitor Cs is connected between the third node N3, which is the midpoint of the third leg G3, and the primary side negative terminal N5, and an active decoupling circuit 15 is formed.

[0045] The current flowing through the first function-switching contactor S1 and the second function-switching contactor S2 is far smaller than the power lines connecting the external AC power supply 4 to the midpoint of each leg, or the power lines connected to the first DC power supply 3 and the second DC power supply 30. Therefore, the first function-switching contactor S1 and the second function-switching contactor S2 can be constructed with smaller components than the first charging contactor Mc1 and the second charging contactor Mc2. As mentioned above, the first charging contactor Mc1 and the second charging contactor Mc2 are, for example, mechanical relays, but the first function-switching contactor S1 and the second function-switching contactor S2 can also be easily constructed using solid-state relays or semiconductor switches. Of course, this does not rule out the possibility that the first function-switching contactor S1 and the second function-switching contactor S2 can be constructed with small mechanical relays.

[0046] Figure 6 shows another configuration example of the on-board charging device 10. Similar to Figure 1, Figure 6 illustrates a configuration that charges two DC power sources and includes a triple active bridge circuit. As with Figure 5, the configuration with a dual active bridge circuit is easily understood and therefore not illustrated or explained.

[0047] The on-board charging device 10 shown in Figure 6 includes a function-switching first contactor S1 and a function-switching second contactor S2, as well as a function-switching third contactor S3. Furthermore, this on-board charging device 10 includes an output-side filter inductor L4 (fourth inductor) whose first terminal x is connected to the positive terminals (primary positive electrode N4) of the first leg G1 and second leg G2, and whose second terminal y is connected to the primary coil T1. The positive terminal z of the third leg G3 is not always connected to the primary positive electrode N4, but is selectively connected to the primary positive electrode N4 by the function-switching third contactor S3. Specifically, the positive terminal z of the third leg G3 is selectively connected to the first terminal x (primary positive electrode N4) and the second terminal y (primary coil T1) of the output-side filter inductor L4 by the function-switching third contactor S3.

[0048] When the external AC power supply 4 is a three-phase AC power supply 4t, each phase of the three-phase AC power supply 4t is connected to the first input terminal N7, the second input terminal N8, and the third input terminal N9, respectively. Also, when the function switching first contactor S1 is closed, the first capacitor Cf1, the second capacitor Cf2, and the third capacitor Cf3 are connected at the capacitor neutral point N0. Also, when the function switching second contactor S2 is opened, the storage capacitor Cs is disconnected. In addition, the first terminal x of the output filter inductor L4 is connected to the positive terminal z of the third leg G3 via the function switching third contactor S3. In this way, when the external AC power supply 4 is a three-phase AC power supply 4t, a three-leg full-bridge circuit 13 is formed, which has an LC filter 1f on the input side and an output filter inductor L4 on the output side.

[0049] When the external AC power supply 4 is a single-phase AC power supply 4s, the positive and negative poles of the single-phase AC power supply 4s are connected to the first input terminal N7 and the second input terminal N8, respectively. Also, by opening the function switching first contactor S1, the third capacitor Cf3 and the third leg G3 are disconnected from the capacitor neutral point N0. Furthermore, the second terminal y of the output filter inductor L4 is connected to the positive terminal z of the third leg G3 via the function switching third contactor S3. In this way, when the external AC power supply 4 is a single-phase AC power supply 4s, a two-leg full-bridge circuit 14 is formed, equipped with an LC filter 1f on the input side and an output filter inductor L4 on the output side. Furthermore, by closing the function switching second contactor S2, a storage capacitor Cs is connected between the third node N3, which is the midpoint of the third leg G3, and the primary side negative terminal N5, forming an active decoupling circuit 15. Thus, when the external AC power supply 4 is a single-phase AC power supply 4s, a two-legged full-bridge circuit 14 and an active decoupling circuit 15 are formed.

[0050] The third function-switching contactor S3 is composed of a mechanical relay. However, the third function-switching contactor S3 has a smaller current capacity than the first charging contactor Mc1 and the second charging contactor Mc2, so a smaller mechanical relay can be used.

[0051] The active decoupling circuit 15 comprises a storage capacitor Cs, a leg (third leg G3) that functions as a charge / discharge control circuit for the storage capacitor Cs, and a third inductor Lf3 that functions as a storage inductor. One end of the storage capacitor Cs is connected to the third node N3, which is the midpoint of the third leg G3, via the third inductor Lf3, and the other end is connected to the primary side negative electrode N5.

[0052] The third leg G3 is switched to synchronize with the pulsations appearing at the output of the two-leg full-bridge circuit 14, i.e., the primary positive electrode N4 and primary negative electrode N5 (pulsations of harmonic components of the frequency of the external AC power supply 4). In other words, the third leg G3 is switched to operate in conjunction with the two-leg full-bridge circuit 14 formed by the first leg G1 and the second leg G2. The third leg G3 is switched to accumulate charge in the storage capacitor Cs during periods when the pulsation component appears on the positive side, and to discharge charge in the storage capacitor Cs during periods when the pulsation component appears on the negative side. By reducing the pulsation component on the primary side of the transformer T, the pulsation component transmitted to the secondary side of the transformer T can be reduced. This makes it easier to increase the smoothing effect of the DC link capacitors (Cdc1, Cdc2).

[0053] When the AC frequencies are the same, single-phase AC tends to produce larger pulsation amplitudes when converted to DC compared to three-phase AC, which has a period shift of 2π / 3 radians. The on-board charging device 10 of this embodiment can selectively supply power from both a three-phase AC power supply 4t and a single-phase AC power supply 4s, and an active decoupling circuit 15 is configured using one leg (third leg G3) that becomes surplus when power is supplied from the single-phase AC power supply 4s. Therefore, in AC-DC conversion from a single-phase AC power supply 4s, which tends to produce large pulsation amplitudes, it is possible to reduce pulsation while suppressing an increase in system costs.

[0054] The following is a brief summary of the in-vehicle charging device (10) mentioned above.

[0055] In one embodiment, the on-board charging device (10) is an on-board charging device (10) that charges at least a first DC power supply (3) with power supplied from an external AC power supply 4, and comprises an AC / DC converter (1) that converts power between the AC power on the external AC power supply (4) side and the first DC power on the first DC power supply (3) side, wherein the AC / DC converter (1) comprises a transformer (T) having a primary coil (T1) and a secondary coil (T2), a primary bridge circuit (11) connected to the primary coil (T1), and a secondary bridge circuit (12) connected to the secondary coil (T2), and is an active bridge circuit The circuit is equipped with a primary bridge circuit (11), which is composed of bidirectional switching elements (11S), and is configured to selectively connect a three-phase AC power supply (4t) and a single-phase AC power supply (4s) as the external AC power supply (4). The primary bridge circuit (11) is configured to switch its function according to the type of external AC power supply (4) between a three-leg full bridge circuit (13) when the external AC power supply (4) is the three-phase AC power supply (4t), and a two-leg full bridge circuit (14) and an active decoupling circuit (15) when the external AC power supply (4) is the single-phase AC power supply (4s).

[0056] This configuration allows for charging the first DC power supply (3) while maintaining isolation between the external AC power supply (4) and the first DC power supply (3) without requiring a separate DC-DC converter after AC-DC conversion, thus reducing the number of switching elements and enabling a smaller on-board charging device (10). Furthermore, the bidirectional switching elements (11S) constituting the primary bridge circuit (11) facilitate soft switching with zero-current switching, which reduces the current flowing through the switching elements during switching. Consequently, losses in the on-board charging device (10) are easily reduced, and system costs are lowered. In addition, since a three-phase AC power supply (4t) and a single-phase AC power supply (4s) can be selectively connected as the external AC power supply (4), it can flexibly accommodate various power supply specifications at the charging location. Furthermore, the circuits for three-phase AC power (4t) and single-phase AC power (4s) are switched using a common primary bridge circuit (11), thus suppressing an increase in system costs.

[0057] Furthermore, the on-board charging device (10) is a triple active bridge circuit in which the AC-DC converter (1) converts power between the AC power on the external AC power source (4) and the first DC power, and further converts power between the AC power on the external AC power source (4) and the second DC power on the second DC power source (30), which is electrically isolated from the first DC power source (3), and the active bridge circuit comprises the secondary coil (T2) having a secondary first coil (T21) and a secondary second coil (T22), and the secondary bridge circuit (12) having a secondary first bridge circuit (121) connected to the secondary first coil (T21) and a secondary second bridge circuit (122) connected to the secondary second coil (T22), and it is preferable to charge the first DC power source (3) and the second DC power source (30) with power supplied from the external AC power source (4).

[0058] In electric vehicles and plug-in hybrid vehicles, in addition to the rotating electric motor (traction motor) that drives the wheels, motors that require relatively high output (workload) may be installed. For example, motors that drive the compressor of the air conditioner that cools and heats the passenger compartment, and auxiliary motors that drive pumps that circulate fluids such as water pumps and oil pumps. In order to supply power to the auxiliary motors, a separate DC power supply may be provided in addition to the DC power supply connected to the traction motor. Furthermore, in open-winding traction motors where the stator coils are not connected to each other by star connection or delta tangent, and are independent of each other, a DC power supply is connected to each end of the stator coil, resulting in the provision of multiple DC power supplies. With this configuration, when multiple DC power supplies are provided in this way, the multiple DC power supplies can be appropriately charged by an external AC power supply.

[0059] Furthermore, the on-board charging device (10) It comprises a function-switching first contactor (S1) and a function-switching second contactor (S2), The primary bridge circuit (11) comprises a first leg (G1), a second leg (G2), and a third leg (G3), respectively, connected between the primary positive electrode (N4) and the primary negative electrode (N5). Between the external AC power supply (4) and the primary bridge circuit (11), A first inductor (Lf1) is connected between the midpoint (N1) of the first leg (G1) and the first input terminal (N7) on the side of the external AC power supply (4), A second inductor (Lf2) is connected between the midpoint (N2) of the second leg (G2) and the second input terminal (N8) on the side of the external AC power supply (4), A third inductor (Lf3) is connected between the midpoint (N3) of the third leg (G3) and the third input terminal (N9) on the side of the external AC power supply (4), A first capacitor (Cf1) is connected between the midpoint (N1) of the first leg (G1) and the capacitor neutral point (N0), A second capacitor (Cf2) is connected between the midpoint (N2) of the second leg (G2) and the neutral point (N0) of the capacitor, A third capacitor (Cf3) is connected between the midpoint (N3) of the third leg (G3) and the capacitor neutral point (N0) via the function switching first contactor (S1), The device comprises a fourth capacitor (Cs) connected between the third input terminal (N9) and the primary side negative electrode (N5) via the function switching second contactor (S2), If the external AC power supply (4) is the three-phase AC power supply (4t), Each phase of the three-phase AC power supply (4t) is connected to the first input terminal (N7), the second input terminal (N8), and the third input terminal (N9), respectively. The function switching first contactor (S1) is closed, and the first capacitor (Cf1), the second capacitor (Cf2), and the third capacitor (Cf3) are connected at the capacitor neutral point (N0), The second contactor (S2) for function switching is opened, and the fourth capacitor (Cs) is disconnected to form the three-legged full-bridge circuit (13). If the external AC power supply (4) is the single-phase AC power supply (4s), The positive and negative poles of the single-phase AC power supply (4s) are connected to the first input terminal (N7) and the second input terminal (N8), respectively. The function-switching first contactor (S1) is opened, and the third capacitor (Cf3) and the third leg (G3) are disconnected from the capacitor neutral point (N0) to form the two-leg full-bridge circuit (14). It is preferable to close the second contactor (S2) for function switching and connect the fourth capacitor (Cs) between the midpoint (N3) of the third leg (G3) and the primary negative electrode (N5) to form the active decoupling circuit (15).

[0060] With this configuration, the circuit's function can be appropriately switched depending on whether the external AC power supply (4) is a three-phase AC power supply (4t) or a single-phase AC power supply (3s) by changing the circuit connection configuration using the first function-switching contactor (S1) and the second function-switching contactor (S2). Furthermore, by providing a fourth capacitor (Cs), when the external AC power supply (4) is a single-phase AC power supply (4s), it is not only possible to simply disconnect one phase of the circuit, but also to appropriately configure an active decoupling circuit (15) using the unused leg of one phase.

[0061] Furthermore, the on-board charging device (10) It comprises a function-switching first contactor (S1), a function-switching second contactor (S2), and a function-switching third contactor (S3), The primary bridge circuit (11) comprises a first leg (G1), a second leg (G2), and a third leg (G3), respectively, connected between the primary positive electrode (N4) and the primary negative electrode (N5). Between the external AC power supply (4) and the primary bridge circuit (11), A first inductor (Lf1) is connected between the midpoint (N1) of the first leg (G1) and the first input terminal (N7) on the side of the external AC power supply (4), A second inductor (Lf2) is connected between the midpoint (N2) of the second leg (G2) and the second input terminal (N8) on the side of the external AC power supply (4), A third inductor (Lf3) is connected between the midpoint (N3) of the third leg (G3) and the third input terminal (N9) on the side of the external AC power supply (4), A first capacitor (Cf1) is connected between the midpoint (N1) of the first leg (G1) and the capacitor neutral point (N0), A second capacitor (Cf2) is connected between the midpoint (N2) of the second leg (G2) and the neutral point (N0) of the capacitor, A third capacitor (Cf3) is connected between the midpoint (N3) of the third leg (G3) and the capacitor neutral point (N0) via the function switching first contactor (S1), The device comprises a fourth capacitor (Cs) connected between the third input terminal (N9) and the primary side negative electrode (N5) via the function switching second contactor (S2), Furthermore, the system includes a fourth inductor (L4) in which the first terminal (x) is connected to the positive terminals of the first leg (G1) and the second leg (G2), and the second terminal (y) is connected to the primary coil, and the first terminal (x) and the second terminal (y) are selectively connected to the positive terminal (z) of the third leg (G3) by the function switching third contactor (S3). If the external AC power supply (4) is the three-phase AC power supply (4t), Each phase of the three-phase AC power supply (4t) is connected to the first input terminal (N7), the second input terminal (N8), and the third input terminal (N9), respectively. The function switching first contactor (S1) is closed, and the first capacitor (Cf1), the second capacitor (Cf2), and the third capacitor (Cf3) are connected at the capacitor neutral point (N0), The second contactor (S2) for function switching is opened, and the fourth capacitor (Cs) is disconnected. The first terminal (x) of the fourth inductor (L4) is connected to the positive terminal (z) of the third leg (G3) via the function-switching third contactor (S3), thereby forming the three-leg full-bridge circuit (13). If the external AC power supply (4) is the single-phase AC power supply (4s), The positive and negative poles of the single-phase AC power supply (4s) are connected to the first input terminal (N7) and the second input terminal (N8), respectively. The function-switching first contactor (S1) is opened, and the third capacitor (Cf3) and the third leg (G3) are disconnected from the capacitor neutral point (N0). The second terminal (y) of the fourth inductor (L4) is connected to the positive terminal (z) of the third leg (G3) via the function-switching third contactor (S3), thereby forming the two-leg full-bridge circuit (14), It is preferable to close the second contactor (S2) for function switching and connect the fourth capacitor (Cs) between the midpoint (N3) of the third leg (G3) and the primary negative electrode (N5) to form the active decoupling circuit (15).

[0062] With this configuration, the circuit's function can be appropriately switched depending on whether the external AC power supply (4) is a three-phase AC power supply (4t) or a single-phase AC power supply (3s) by changing the circuit connection configuration using the first function-switching contactor (S1) and the second function-switching contactor (S2). Furthermore, by providing a fourth capacitor (Cs), when the external AC power supply (4) is a single-phase AC power supply (4s), it is not only possible to simply disconnect one phase of the circuit, but also to appropriately configure an active decoupling circuit (15) using the unused leg of one phase. In addition, by providing a third function-switching contactor (S3), an inductive filter can be selectively placed at the output of either a three-leg full-bridge circuit or a two-leg full-bridge circuit. [Explanation of Symbols]

[0063] 1: AC-DC converter, 3: First DC power supply, 4: External AC power supply, 4s: Single-phase AC power supply, 4t: Three-phase AC power supply, 10: On-board charging device, 11: Primary bridge circuit, 11S: Bidirectional switching element, 13: Full bridge circuit, 14: Full bridge circuit, 15: Active decoupling circuit, 21: First chopper circuit, 22: Second chopper circuit, 30: Second DC power supply, 50: Second inverter, 121: Secondary first bridge circuit, 122: Secondary second bridge circuit, x: First terminal (first terminal of the fourth inductor), y: Second terminal (second terminal of the fourth inductor), z: Positive terminal of the third leg, Cf1: First filter capacitor (first capacitor), Cf2: Second filter capacitor (second capacitor), Cf3: Third filter capacitor (third capacitor), Cs: Storage capacitor (4th capacitor), G1: 1st leg, G2: 2nd leg, G3: 3rd leg, K4: 4th inductor, L4: 4th inductor, Lf1: 1st inductor, Lf2: 2nd inductor, Lf3: 3rd inductor, N0: Capacitor neutral point, N1: 1st node (midpoint of 1st leg), N2: 2nd node (midpoint of 2nd leg), N3: 3rd node (midpoint of 3rd leg) (Point), N4: 4th node (primary side positive terminal), N5: 5th node (primary side negative terminal), N6: 6th node, N7: 1st input terminal, N8: 2nd input terminal, N9: 3rd input terminal, S1: Function switching 1st contactor, S2: Function switching 2nd contactor, S3: Function switching 3rd contactor, T: Transformer, T1: Primary side coil, T2: Secondary side coil, T21: Secondary side 1st coil, T22: Secondary side 2nd coil

Claims

1. An on-board charging device that charges at least a first DC power source with power supplied from an external AC power source, The system includes an AC-DC converter that converts power between the AC power from the external AC power source and the first DC power from the first DC power source. The AC-DC converter is, A transformer equipped with a primary coil and a secondary coil, A primary bridge circuit connected to the primary coil, The active bridge circuit comprises a secondary bridge circuit connected to the secondary coil, The primary bridge circuit is composed of bidirectional switching elements. The aforementioned external AC power supply is configured to allow selective connection of a three-phase AC power supply and a single-phase AC power supply. The aforementioned primary bridge circuit is The three-legged full-bridge circuit when the external AC power supply is the three-phase AC power supply, The two-legged full-bridge circuit and active decoupling circuit when the external AC power supply is the single-phase AC power supply, An in-vehicle charging device configured to switch functions according to the type of external AC power supply.

2. The AC-DC converter is, The AC power on the external AC power source is converted between the AC power and the first DC power, and further, the AC power on the external AC power source is converted between the AC power and the second DC power on the second DC power source, which is electrically isolated from the first DC power source. The aforementioned active bridge circuit is The secondary coil comprises a secondary first coil and a secondary second coil. The secondary bridge circuit is a triple active bridge circuit comprising a secondary first bridge circuit connected to the secondary first coil and a secondary second bridge circuit connected to the secondary second coil. The on-board charging device according to claim 1, wherein the first DC power supply and the second DC power supply are charged by power supplied from the external AC power supply.

3. It comprises a first function-switching contactor and a second function-switching contactor. The primary bridge circuit comprises a first leg, a second leg, and a third leg, each connected between the primary positive electrode and the primary negative electrode. Between the external AC power supply and the primary bridge circuit, A first inductor connected between the midpoint of the first leg and the first input terminal on the side of the external AC power supply, A second inductor is connected between the midpoint of the second leg and the second input terminal on the side of the external AC power supply, A third inductor is connected between the midpoint of the third leg and the third input terminal on the external AC power supply side, A first capacitor connected between the midpoint of the first leg and the neutral point of the capacitor, A second capacitor connected between the midpoint of the second leg and the neutral point of the capacitor, A third capacitor is connected between the midpoint of the third leg and the neutral point of the capacitor via the function-switching first contactor, The device comprises a fourth capacitor connected between the third input terminal and the primary side negative electrode via the function switching second contactor, When the external AC power supply is the three-phase AC power supply, Each phase of the three-phase AC power supply is connected to the first input terminal, the second input terminal, and the third input terminal, respectively. The function switching first contactor is closed, and the first capacitor, the second capacitor, and the third capacitor are connected at the capacitor neutral point, By opening the second contactor for function switching and disconnecting the fourth capacitor, the three-legged full-bridge circuit is formed. When the external AC power source is the single-phase AC power source, The positive and negative poles of the single-phase AC power supply are connected to the first input terminal and the second input terminal, respectively. By opening the function-switching first contactor, the third capacitor and the third leg are disconnected from the capacitor neutral point, thereby forming the two-leg full-bridge circuit. The in-vehicle charging device according to claim 1 or 2, wherein the function switching second contactor is closed and the fourth capacitor is connected between the midpoint of the third leg and the primary side negative electrode to form the active decoupling circuit.

4. It comprises a first function-switching contactor, a second function-switching contactor, and a third function-switching contactor. The primary bridge circuit comprises a first leg, a second leg, and a third leg, each connected between the primary positive electrode and the primary negative electrode. Between the external AC power supply and the primary bridge circuit, A first inductor connected between the midpoint of the first leg and the first input terminal on the side of the external AC power supply, A second inductor is connected between the midpoint of the second leg and the second input terminal on the side of the external AC power supply, A third inductor is connected between the midpoint of the third leg and the third input terminal on the external AC power supply side, A first capacitor connected between the midpoint of the first leg and the neutral point of the capacitor, A second capacitor connected between the midpoint of the second leg and the neutral point of the capacitor, A third capacitor is connected between the midpoint of the third leg and the neutral point of the capacitor via the function-switching first contactor, The device comprises a fourth capacitor connected between the third input terminal and the primary side negative electrode via the function switching second contactor, Furthermore, the device includes a fourth inductor in which the first terminal is connected to the positive terminals of the first and second legs, and the second terminal is connected to the primary coil, and the first and second terminals are selectively connected to the positive terminal of the third leg by the function switching third contactor. When the external AC power supply is the three-phase AC power supply, Each phase of the three-phase AC power supply is connected to the first input terminal, the second input terminal, and the third input terminal, respectively. The function switching first contactor is closed, and the first capacitor, the second capacitor, and the third capacitor are connected at the capacitor neutral point, The second contactor for function switching is opened, and the fourth capacitor is disconnected. The first terminal of the fourth inductor is connected to the positive terminal of the third leg via the function-switching third contactor, thereby forming the three-leg full-bridge circuit. When the external AC power source is the single-phase AC power source, The positive and negative poles of the single-phase AC power supply are connected to the first input terminal and the second input terminal, respectively. The function switching first contactor is opened, and the third capacitor and the third leg are disconnected from the capacitor neutral point. The second terminal of the fourth inductor is connected to the positive terminal of the third leg via the function-switching third contactor, thereby forming the two-leg full-bridge circuit. The in-vehicle charging device according to claim 1 or 2, wherein the function switching second contactor is closed and the fourth capacitor is connected between the midpoint of the third leg and the primary side negative electrode to form the active decoupling circuit.

Images