Charging and discharging system, vehicle-mounted power supply and electric vehicle

Abstract

The utility model relates to a charging and discharging system, a vehicle-mounted power supply and an electric vehicle, the system is applied to the electric vehicle, and the system comprises a switch module; a power factor correction circuit; and the power factor correction circuit is connected to the auxiliary battery through the switch module in an on-off manner, so that a vehicle-mounted energy supply device supplies power to the auxiliary battery through the power factor correction circuit. Emergency power supply can be carried out through the auxiliary circuit, no extra circuit needs to be added, electric appliance isolation of the whole vehicle can be guaranteed, and application is more convenient and safer.

Description

Technical Field

[0001] The present application relates to the technical field of charging circuits, and in particular to a charging and discharging system, a vehicle-mounted power supply and an electric vehicle. Background Art

[0002] At present, the electrical system of electric vehicles is generally divided into high-voltage system and low-voltage system. The electrical system connected to the electric vehicle power battery is the high-voltage system, and the electrical system connected to the low-voltage auxiliary battery of the electric vehicle is the low-voltage system. The high-voltage system is responsible for the distribution of electric energy to the high-voltage components of electric vehicles, such as traction motor drivers and generator drivers. The low-voltage system is responsible for the distribution of electric energy to the low-voltage components of electric vehicles, such as the central control system and multimedia system. The power supply interruption of the low-voltage system will cause all high-voltage and low-voltage systems of the vehicle to be completely unable to work, which may cause serious accidents.

[0003] In the related art, in order to improve the reliability of the low-voltage power supply system of electric vehicles, redundant DC / DC circuit modules are used to provide emergency power supply for the low-voltage system of the entire vehicle in the event of a failure of the low-voltage isolated DC / DC converter of the electric vehicle. However, the solutions of the related art are difficult to achieve high and low voltage isolation without adding additional circuits, and are inconvenient to use. Utility Model Content

[0004] The present application is proposed to solve the above-mentioned problems. According to one aspect of the present application, a charging and discharging system is provided, which is applied to an electric vehicle. The system includes: a switch module; a power factor correction circuit; and an auxiliary battery. The power factor correction circuit can be connected to the auxiliary battery through the switch module so that the vehicle-mounted energy supply device can supply power to the auxiliary battery through the power factor correction circuit.

[0005] Exemplarily, the power factor correction circuit includes at least one bridge arm, and the switch module can connect and disconnect the midpoint of the bridge arm of the power factor correction circuit and the auxiliary battery, so that the vehicle-mounted power supply device can supply power to the auxiliary battery through the power factor correction circuit.

[0006] Exemplarily, the power factor correction circuit includes at least two bridge arms, the switch module can connect the midpoint of at least one of the bridge arms and the first pole of the auxiliary battery, and the busbar of the power factor correction circuit is connected to the second pole of the auxiliary battery; or, the switch module connects the midpoints of two bridge arms and the two poles of the auxiliary battery.

[0007] Exemplarily, the switch module includes: a first switch unit and a second switch unit, the first switch unit can connect the midpoint of the bridge arm and the first pole of the auxiliary battery on and off, and the second switch unit can connect the second pole of the auxiliary battery and the bus of the power factor correction circuit on and off; the switch module is configured as follows: the first switch unit connects at least one midpoint of the bridge arm to the first pole of the auxiliary battery, and the second switch unit connects the bus of the power factor correction circuit to the second pole of the auxiliary battery, so that the vehicle-mounted energy supply device supplies power to the auxiliary battery through the power factor correction circuit.

[0008] Exemplarily, the first switch unit includes: a first switch, a second switch and a third switch; the power factor correction circuit includes a first bridge arm, a second bridge arm and a third bridge arm; one end of the first switch is connected to the midpoint of the first bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery; one end of the second switch is connected to the midpoint of the second bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery; one end of the third switch is connected to the midpoint of the third bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery.

[0009] Exemplarily, the vehicle-mounted energy supply device includes a power battery, and the system further includes a first conversion circuit, a first end of the first conversion circuit is connected to the power battery, and a second end of the first conversion circuit is connected to the power factor correction circuit.

[0010] Exemplarily, the switch module includes a first switch and a second switch, and the power factor correction circuit includes at least a first bridge arm and a second bridge arm; one end of the first switch is connected to the midpoint of the first bridge arm, and the other end can be switchably connected to the charging port or the first pole of the auxiliary battery; one end of the second switch is connected to the midpoint of the second bridge arm, and the other end can be switchably connected to the second pole of the auxiliary battery.

[0011] Exemplarily, the vehicle-mounted energy supply device includes a power battery and a photovoltaic component, and the system also includes a first conversion circuit, a first end of the first conversion circuit is connected to the power battery, and a second end of the first conversion circuit and the photovoltaic component are both connected to the power factor correction circuit.

[0012] Exemplarily, the charging port is connected to a charging device or a load; the photovoltaic component charges the power battery through the first conversion circuit; or, the photovoltaic component supplies power to the load through the power factor correction circuit and the charging port; or, the photovoltaic component supplies power to the auxiliary battery through the power factor correction circuit.

[0013] Exemplarily, the charging port is connected to a charging device or a load; the switch module can also be configured to: connect the charging port and the power factor correction circuit, the charging device charges the power battery through the charging port, the power factor correction circuit and the first conversion circuit; or, the power battery supplies power to the load through the first conversion circuit, the power factor correction circuit and the charging port.

[0014] Exemplarily, the charging port includes a first phase line, a second phase line, a third phase line and a negative terminal, and the power factor correction circuit also includes a first inductor, a second inductor and a third inductor, the first inductor is connected to the midpoint of the first bridge arm, the second inductor is connected to the midpoint of the second bridge arm, and the third inductor is connected to the midpoint of the third bridge arm; the first end of the first switch is connected to the first inductor, and the second end of the first switch can be switchably connected to the first phase line or the first pole of the auxiliary battery; the first end of the second switch is connected to the second inductor, and the second end of the second switch can be switchably connected to the second phase line or the first pole of the auxiliary battery; the third switch includes a first sub-switch and a second sub-switch, the first end of the first sub-switch is connected to the third inductor, and the second end of the first sub-switch can be switchably connected to the third phase line or the first pole of the auxiliary battery; the third inductor is connected to the negative terminal in a switchable manner through the second sub-switch.

[0015] Exemplarily, the charging port is connected to a charging device, and the switch module is configured as follows: one of the first switch, the second switch, and the third switch is connected to the charging port and the power factor correction circuit, the second sub-switch is closed, and the second switch unit is disconnected; the charging device performs single-phase inverter charging for the power battery through the charging port, the power factor correction circuit, and the first conversion circuit.

[0016] Exemplarily, the charging port is connected to a load, and the switch module is configured as follows: one of the first switch, the second switch, and the third switch is connected to the charging port and the power factor correction circuit, the second sub-switch is closed, and the second switch unit is disconnected; the power battery supplies power to the load through the first conversion circuit, the power factor correction circuit, and the charging port.

[0017] Exemplarily, the charging port is connected to a charging device, and the switch module is configured as follows: the first switch, the second switch, and the third switch are all connected to the charging port and the power factor correction circuit, the second sub-switch is disconnected, and the second switch unit is disconnected; the charging device performs three-phase inverter charging for the power battery through the charging port, the power factor correction circuit, and the first conversion circuit.

[0018] Exemplarily, the charging port is connected to a load, and the switch module is configured as follows: the first switch, the second switch, and the third switch are all connected to the charging port and the power factor correction circuit, the second sub-switch is disconnected, and the second switch unit is disconnected; the power battery supplies power to the load through the first conversion circuit, the power factor correction circuit, and the charging port.

[0019] Exemplarily, the switch module is configured as follows: the first switch, the second switch, and the third switch are all connected to the first pole of the auxiliary battery and the power factor correction circuit, the second sub-switch is disconnected, and the second switch unit is closed to connect the second pole of the auxiliary battery and the bus of the power factor correction circuit; the power battery supplies power to the auxiliary battery through the first conversion circuit and the power factor correction circuit.

[0020] Exemplarily, it also includes a second conversion circuit, which connects the vehicle-mounted energy supply device and the auxiliary battery to power the auxiliary battery; the switch module is configured to: when the second conversion circuit fails, connect the power factor correction circuit and the auxiliary battery so that the vehicle-mounted energy supply device powers the auxiliary battery through the first conversion circuit and the power factor correction circuit of the second conversion circuit.

[0021] According to another aspect of the present application, a vehicle-mounted power supply is provided, and the vehicle-mounted power supply includes the above-mentioned charging and discharging system.

[0022] According to another aspect of the present application, an electric vehicle is provided, comprising the above-mentioned on-board power supply.

[0023] The charging and discharging system in this application is provided with a power factor correction circuit, which can charge the vehicle-mounted energy supply device such as the power battery through the charging device after AC-DC conversion, and can also control the connection between the auxiliary battery and the power factor correction circuit through the switch module, so as to supply power to the auxiliary battery through the power factor correction circuit, so that when a fault occurs on the low-voltage side, emergency power supply is provided to the load to ensure the safety of the vehicle. This application uses a switch module, which does not require the addition of additional circuits, is more convenient to use, and effectively ensures the driving safety of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] By describing the embodiments of the present application in more detail in conjunction with the accompanying drawings, the above and other purposes, features and advantages of the present application will become more apparent. The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0025] Figure 1 The structural block diagram of the charging and discharging system in the first embodiment of the present application is shown.

[0026] Figure 2 A circuit diagram of a charging and discharging system in a non-working state in the first embodiment of the present application is shown.

[0027] Figure 3 A circuit diagram of a charging and discharging system in a single-phase inverter charging state in the first embodiment of the present application is shown.

[0028] Figure 4 A circuit diagram of a charging and discharging system in a single-phase inverter discharge state in the first embodiment of the present application is shown.

[0029] Figure 5 A circuit diagram of a charging and discharging system performing three-phase inverter charging in Embodiment 1 of the present application is shown.

[0030] Figure 6 A circuit diagram of a charging and discharging system in a three-phase inverter discharge state in Embodiment 1 of the present application is shown.

[0031] Figure 7 A circuit diagram of the circuit in the first embodiment of the present application in an emergency power supply state is shown.

[0032] Figure 8 The circuit diagram of the charging and discharging system in the second embodiment of the present application is shown. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present application more obvious, the example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0034] Embodiment 1

[0035] like Figure 1 As shown, an embodiment of the present application provides a charging and discharging system, which is applied to an electric vehicle, and includes: a switch module; a power factor correction circuit; an auxiliary battery, wherein the power factor correction circuit can be connected to the auxiliary battery through the switch module so that the vehicle-mounted energy supply device can supply power to the auxiliary battery through the power factor correction circuit.

[0036] The charging and discharging system in the embodiment of the present application is provided with a power factor correction circuit, which can charge the battery and other vehicle-mounted energy supply devices through the charging device after AC-DC conversion, and can also control the auxiliary battery and the power factor correction circuit to be connected through the switch module, so as to supply power to the auxiliary battery through the power factor correction circuit, so that when a fault occurs on the low-voltage side, emergency power supply is provided to the load to ensure vehicle safety. The present application uses a switch module, does not need to add additional circuits, is more convenient to use, and effectively ensures the driving safety of electric vehicles.

[0037] like Figure 2 As shown, it is a circuit diagram of the charging and discharging system in the embodiment of the present application when it is not working.

[0038] Exemplarily, the vehicle-mounted energy supply device includes a power battery, and the system further includes a first conversion circuit, wherein the first end of the first conversion circuit is connected to the power battery, and the second end of the first conversion circuit is connected to the power factor correction circuit. The above-mentioned power factor correction circuit is a three-phase PFC circuit or a single-phase PFC circuit, and the first conversion circuit is a first DC / DC circuit, that is, a high-voltage isolated DC / DC circuit in the figure. The first load is a low-voltage load of the electric vehicle.

[0039] Exemplarily, the charging and discharging system further includes a second conversion circuit, which is a second DC / DC circuit, and which includes a low-voltage isolated DC / D converter, a first end of which is connected to a power battery, and a second end of which is connected to an auxiliary battery and a first load. The first load is a low-voltage load of an electric vehicle in the figure.

[0040] The switch module is configured as follows: when the low-voltage isolated DC / D converter fails, the power factor correction circuit and the auxiliary circuit are connected, so that the power battery supplies power to the auxiliary battery and the first load through the first DC / DC circuit, the power factor correction circuit and the auxiliary circuit. That is, when the low-voltage isolated DC / D converter does not fail, the switch module will never connect the power factor correction circuit and the auxiliary circuit, and the system on the low-voltage side can operate normally.

[0041] Exemplarily, the switch module can also be configured to connect the power factor correction circuit and the second load through the charging port, so that the power battery supplies power to the second load through the first DC / DC circuit, the power factor correction circuit and the charging port. The second load is a high-voltage load, which can be a three-phase AC load, a single-phase AC load and a corresponding discharge gun.

[0042] Exemplarily, the power factor correction circuit includes at least one bridge arm, and the switch module can connect and disconnect the midpoint of the bridge arm of the power factor correction circuit and the auxiliary battery, so that the vehicle-mounted energy supply device (power battery) supplies power to the auxiliary battery through the power factor correction circuit.

[0043] Exemplarily, the switch module includes: a first switch unit and a second switch unit, the first switch unit can be switched on and off to connect the midpoint of the bridge arm and the first pole of the auxiliary battery, and the second switch unit can be switched on and off to connect the second pole of the auxiliary battery and the busbar of the power factor correction circuit. The switch module is configured as follows: the first switch unit connects at least one midpoint of the bridge arm to the first pole of the auxiliary battery, and the second switch unit connects the busbar of the power factor correction circuit to the second pole of the auxiliary battery, so that the on-board energy supply device supplies power to the auxiliary battery through the power factor correction circuit.

[0044] Wherein, the first switch unit includes: a first switch, a second switch and a third switch; the power factor correction circuit includes a first bridge arm, a second bridge arm and a third bridge arm;

[0045] One end of the first switch is connected to the midpoint of the first bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery; one end of the second switch is connected to the midpoint of the second bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery; one end of the third switch is connected to the midpoint of the third bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery.

[0046] like Figure 2 As shown, exemplarily, the power factor correction circuit is a three-phase PFC circuit. The three-phase PFC circuit includes a first MOS tube Q1, a second MOS tube Q2 and a first inductor, a third MOS tube Q3, a fourth MOS tube Q4 and a second inductor, a fifth MOS tube Q5, a sixth MOS tube Q6 and a third inductor, the first MOS tube Q1 and the second MOS tube Q2 form a first bridge arm, the third MOS tube Q3 and the fourth MOS tube Q4 form a second bridge arm, and the fifth MOS tube Q5 and the sixth MOS tube Q6 form a third bridge arm.

[0047] The first end of the first inductor is connected to the midpoint of the first bridge arm, the first end of the second inductor is connected to the midpoint of the second bridge arm, and the first end of the third inductor is connected to the midpoint of the third bridge arm. The first ends of the first bridge arm, the second bridge arm, and the third bridge arm are connected to the first bus terminal, and the second ends of the first bridge arm, the second bridge arm, and the third bridge arm are connected to the second bus terminal. The second switch unit S5 can be turned on and off to connect the negative electrode of the auxiliary circuit and the second bus terminal.

[0048] Exemplarily, the high-voltage isolated DC / DC circuit adopts a bidirectional CLLC circuit. The first side and the second side of the high-voltage isolated DC / DC circuit are used to connect the power factor correction circuit and the power battery, respectively. The first side of the high-voltage isolated DC / DC circuit is provided with a seventh MOS tube Q7, an eighth MOS tube Q8, a ninth MOS tube Q9, and a tenth MOS tube Q10. The seventh MOS tube Q7 and the eighth MOS tube Q8 form a fourth bridge arm, and the ninth MOS tube Q9 and the tenth MOS tube Q10 form a fifth bridge arm. The second side of the high-voltage isolated DC / DC circuit is provided with an eleventh MOS tube Q11, a twelfth MOS tube Q12, a thirteenth MOS tube Q13, and a fourteenth MOS tube Q14. The eleventh MOS tube Q11 and the twelfth MOS tube Q12 form a sixth bridge arm, and the thirteenth MOS tube Q13 and the fourteenth MOS tube Q14 form a seventh bridge arm.

[0049] The three-phase PFC circuit in the embodiment of the present application can realize the conversion of AC-DC, so as to be used for charging or discharging the power battery. In addition, when the power battery is used to supply power to the auxiliary battery and the low-voltage load of the electric vehicle, the three-phase PFC circuit may not perform the conversion of DC to AC, so that the power battery can provide DC power to the auxiliary circuit.

[0050] In the three-phase PFC circuit, the second bus terminal is the negative pole, and the second bus terminal is used to connect to the second switch unit S5. In addition, the second bus terminal is also connected to the first ground terminal, so that it is connected to the first high-voltage ground, that is, PGND (protective ground), and the negative pole of the auxiliary circuit is also connected to the second ground terminal, so that it is connected to the low-voltage ground, that is, GND in the figure. The negative pole of the power battery is connected to the third ground terminal, that is, HGND in the figure. The power safety of the circuit is ensured by each ground terminal.

[0051] Exemplarily, the charging port includes a first phase line, a second phase line, a third phase line and a negative terminal, and the switch module includes a first switch S1, a second switch S2 and a third switch, wherein the third switch includes a first sub-switch S3 and a second sub-switch S4, and S1-S3 are all single-pole double-throw switches.

[0052] The common terminal of the first switch S1 is connected to the second terminal of the first inductor, the first switching terminal of the first switch is connected to the first phase line, and the second switching terminal of the first switch S1 is connected to the positive electrode of the auxiliary circuit. The common terminal of the second switch S2 is connected to the second terminal of the second inductor, the first switching terminal of the second switch S2 is connected to the second phase line, and the second switching terminal of the second switch S2 is connected to the positive electrode of the auxiliary circuit. The common terminal of the third switch S3 is connected to the second terminal of the third inductor, the first switching terminal of the third switch S3 is connected to the third phase line, and the second switching terminal of the third switch S3 is connected to the positive electrode of the auxiliary circuit. The second sub-switch S4 can be connected to the negative terminal and the second terminal of the third inductor in an on-off manner.

[0053] The charging and discharging system in the embodiment of the present application switches different charging or discharging working states by turning on and off the above-mentioned switch module, namely the first switch S1, the second switch S2, the third switch S3 and the second sub-switch S4.

[0054] Combine the following Figure 3-Figure 6 The charging and discharging states of the charging and discharging system in the embodiment of the present application are described.

[0055] like Figure 3 As shown, it is a circuit diagram of the charging and discharging system in the embodiment of the present application in the single-phase inverter charging state.

[0056] The configuration state of the switch module is: one of the first switch S1, the second switch S2 and the third switch S3 connects the charging port and the three-phase PFC circuit, the second sub-switch S4 is closed, and the second switch unit S5 is disconnected. For example, taking the first switch S1 as an example, the first switch S1 is connected to the first phase line of the charging port. In the charging state, the charging port is connected to the unidirectional AC charging pile. The second sub-switch S4 is in a closed state, so that the negative end of the charging port is connected to the second end of the third inductor.

[0057] The first switch S1, the second switch S2, the third switch S3, the second sub-switch S4 and the second switch unit S5 are all controlled by the on-board charger (OBC) controller, that is, the OBC controller. Exemplarily, the OBC controller is an on-board MCU. The OBC controller determines to enter the single-phase charging working mode according to the CC / CP signal detected by the AC charging port and the AC voltage signal of the first phase line-third phase line. Among them, the CC signal is a resistance signal, which represents whether the cable has been connected and the capacity of the cable. The CP signal represents the capacity of the power supply device. Charging starts after the confirmation signal. The power flow of the three-phase PFC circuit, the high-voltage isolated PFC circuit and the high-voltage isolated DC / DC circuit are all in the forward flow working mode from left to right. In this working mode, the high-voltage isolated DC / DC circuit controls the conversion of the DC power output by the three-phase PFC circuit into the DC power of the electric vehicle power battery by adjusting the frequency of the drive signal of the seventh MOS tube Q7-the tenth MOS tube Q10 (the duty cycle is fixed at 50%), thereby realizing the single-phase inverter charging of the power battery.

[0058] In this state, the vehicle is stationary, the second switch unit S5 is disconnected, the first ground terminal in the three-phase PFC circuit and the second ground terminal on the auxiliary circuit are isolated, achieving electrical isolation between the high-voltage side and the low-voltage side, thereby ensuring power safety.

[0059] like Figure 4 As shown, it is a circuit diagram of the charging and discharging system in the embodiment of the present application in the single-phase inverter discharge state.

[0060] The configuration state of the switch module is: one of the first switch S1, the second switch S2 and the third switch S3 connects the charging port and the three-phase PFC circuit, the second sub-switch S4 is closed, and the second switch unit S5 is disconnected. For example, taking the first switch S1 as an example, the first switch S1 is connected to the first phase line of the charging port. In the charging state, the charging port is connected to the unidirectional AC discharge gun (single-phase AC load). The second sub-switch S4 is in a closed state, so that the negative end of the charging port is connected to the second end of the third inductor.

[0061] In this state, the OBC controller confirms that it has entered the single-phase inverter discharge working state according to the CC signal of the charging port. In the single-phase inverter discharge working mode, the power flow of the three-phase PFC circuit and the high-voltage isolation DC / DC circuit are both in the reverse flow working mode from right to left. In this working mode, the high-voltage isolation DC / DC circuit controls the conversion of the DC power of the power battery into the intermediate-level DC power of the bus voltage of the three-phase PFC circuit by adjusting the frequency of the drive signal of the eleventh MOS tube Q11-the fourteenth MOS tube Q14 (the duty cycle is fixed to 50%). The three-phase PFC circuit controls the conversion of the intermediate-level DC power of the bus voltage of the three-phase PFC circuit into single-phase AC power to power the single-phase AC load (discharge gun) by adjusting the duty cycle of the drive signal of the first MOS tube Q1, the second MOS tube Q2, the fifth MOS tube Q5, and the sixth MOS tube Q6 (the frequency is fixed).

[0062] In this state, the vehicle is stationary, the second switch unit S5 is disconnected, the first ground terminal in the three-phase PFC circuit and the second ground terminal on the auxiliary circuit are isolated, achieving electrical isolation between the high-voltage side and the low-voltage side, thereby ensuring power safety.

[0063] like Figure 5 As shown, it is a circuit diagram of the charging and discharging system for three-phase inverter charging in an embodiment of the present application.

[0064] Each switch in the switch module is controlled by an OBC controller (such as an on-board MCU). The switch module is configured as follows: the first switch S1, the second switch S2, and the third switch S3 are all connected to the charging port and the three-phase PFC circuit, the second sub-switch S4 is disconnected, and the second switch unit S5 is disconnected. The charging port is connected to the three-phase AC charging pile, so that the three-phase charging pile performs AC-DC conversion through the charging port and the three-phase PFC circuit, and then performs three-phase inverter charging for the power battery through the high-voltage isolation DC / DC circuit.

[0065] In this state, the OBC controller confirms that it has entered the three-phase charging working mode based on the CC / CP signal detected at the charging port and the AC voltage signal of the first phase line to the third phase line. In the three-phase charging working state, the power flow of the three-phase PFC circuit and the high-voltage isolated DC / DC circuit are both in the forward flow working mode from left to right. In this working mode, the high-voltage isolated DC / DC circuit controls the conversion of the DC power output by the three-phase PFC circuit into the DC power of the electric vehicle power battery by adjusting the frequency of the drive signal of the seventh MOS tube Q7-the tenth MOS tube Q10 (the duty cycle is fixed at 50%), thereby charging the power battery.

[0066] In this state, the vehicle is stationary, the second switch unit S5 is disconnected, the first ground terminal in the three-phase PFC circuit and the second ground terminal on the auxiliary circuit are isolated, achieving electrical isolation between the high-voltage side and the low-voltage side, thereby ensuring power safety.

[0067] like Figure 6 As shown, it is a circuit diagram of the charging and discharging system performing three-phase inverter discharge in the embodiment of the present application.

[0068] Each switch in the switch module is controlled by an OBC controller (such as an on-board MCU). The switch module is configured as follows: the first switch S1, the second switch S2, and the third switch S3 are all connected to the charging port and the three-phase PFC circuit, the second sub-switch S4 is disconnected, and the second switch unit S5 is disconnected. The charging port is connected to the three-phase AC load (discharge gun) so that the power battery is converted from DC to AC through the three-phase PFC circuit after passing through the high-voltage isolation DC / DC circuit, and then three-phase inverter power is provided to the three-phase AC load through the charging port.

[0069] In this state, the OBC controller determines to enter the three-phase inverter discharge working mode according to the CC signal detected at the charging port. In the three-phase inverter discharge working mode, the power flow of the three-phase PFC circuit and the high-voltage isolation DC / DC circuit are in the reverse flow working mode from right to left. In this working mode, the high-voltage isolation DC / DC circuit controls the conversion of the DC power of the power battery into the intermediate DC power of the bus voltage of the three-phase PFC circuit by adjusting the frequency of the drive signal of the eleventh MOS tube Q11-the fourteenth MOS tube Q14 (the duty cycle is fixed at 50%). Afterwards, the three-phase PFC circuit controls the conversion of the intermediate DC power of the three-phase PFC bus voltage and the DC power output by the solar cell into three-phase AC power to power the three-phase AC load by adjusting the duty cycle of the drive signal of the first MOS tube Q1-the sixth MOS tube Q6 (the frequency is fixed).

[0070] In this state, the vehicle is stationary, the second switch unit S5 is disconnected, the first ground terminal in the three-phase PFC circuit and the second ground terminal on the auxiliary circuit are isolated, achieving electrical isolation between the high-voltage side and the low-voltage side, thereby ensuring power safety.

[0071] like Figure 7 As shown, it is a circuit diagram of the charging and discharging system in the embodiment of the present application in the emergency power supply state.

[0072] When the car is stationary or moving, and a low-voltage isolated DC / DC converter fault is detected, this working state is entered. For example, the auxiliary battery is connected to a BMS (battery management system) so that the state of the auxiliary battery (such as power) can be obtained. When the power of the auxiliary battery is low, the emergency power supply state is entered to power the auxiliary circuit (including the auxiliary battery and the low-voltage load of the electric vehicle).

[0073] Exemplarily, the fault information of the low-voltage isolated DC / DC converter can send fault status information to the OBC controller via CAN (Controller Area Network), or the OBC periodically sends a fault query command to the low-voltage isolated DC / DC converter via the CAN communication network. Once it is determined that the low-voltage isolated DC / DC converter is in a fault state and lasts for a preset time, the OBC enters the emergency low-voltage power supply working mode and sends a working status command to the vehicle alarm system controller via the CAN communication network. The vehicle alarm system prompts the driver that the vehicle is currently in an emergency driving state, thereby avoiding safety accidents caused by the vehicle breaking down.

[0074] As shown in the figure, each switch in the switch module is controlled by an OBC controller (such as an on-board MCU). The switch module is configured as follows: the first switch S1, the second switch S2, and the third switch S3 are all connected to the positive pole of the auxiliary circuit and the three-phase PFC circuit, the second sub-switch S4 is disconnected, and the second switch unit S5 is closed so that the negative pole of the auxiliary circuit is connected to the second bus terminal of the three-phase PFC circuit. Compared with the above working state, in this state, the three-phase PFC circuit is no longer connected to the charging port but is connected to the auxiliary circuit to power the auxiliary circuit.

[0075] As shown in the figure, when the OBC controller detects that the low-voltage isolated DC / DC converter is in a fault state, it determines to enter the emergency power supply working mode. In the emergency power supply working mode, the power flow of the three-phase PFC circuit and the high-voltage isolated DC / DC circuit are both in the reverse flow working mode from right to left.

[0076] The high-voltage isolated DC / DC circuit is in reverse working mode, and the bus voltage Vpfc of the three-phase PFC circuit is controlled at a stable value. The three-phase PFC circuit is in synchronous buck working mode, and the switching duty ratio of the first MOS tube Q1-the sixth MOS tube Q6 on the first bridge arm-the third bridge arm is adjusted to control the voltage at the auxiliary battery end at a stable value, so as to continuously supply power to the low-voltage load of the electric vehicle and charge the low-voltage auxiliary battery. The switching control signal frequency and duty ratio of the first MOS tube Q1-the sixth MOS tube Q6 in the above-mentioned three-phase PFC circuit are consistent, and the driving signal of the MOS tube is complementary. Taking the opening time of the MOS tube on the first bridge arm as the reference, the opening time of the MOS tube on the second bridge arm and the third bridge arm are phase-shifted by 120° and 240° respectively in the switching cycle, so that the output inductor current of the first bridge arm-the third bridge arm is staggered and superimposed, reducing the total output ripple current, and making the output ripple voltage lower.

[0077] In addition, the output end of the three-phase PFC circuit connected to the auxiliary circuit is in constant voltage current limiting control mode. The current output through the first bridge arm-the third bridge arm is the effective value of the maximum AC current per phase under full power conditions. For example, for a circuit with a rated power of 22kW, the design value of the maximum current per phase of the first bridge arm-the third bridge arm is 32A. In the emergency low-voltage power supply working mode, the total output current limit of the three-phase PFC circuit to the low-voltage load of the electric vehicle is 32*3=96A.

[0078] When the actual current demand of the low-voltage load of the electric vehicle is less than the limit of 96A, the duty cycle of the switch control signal of the MOS tube of the first bridge arm-the third bridge arm of the three-phase PFC circuit is adjusted in real time according to the load requirements to reach the current value that meets the load requirements, and the three-phase PFC circuit is in constant voltage output control mode. When the actual current demand of the low-voltage load of the electric vehicle is greater than the limit of 96A, the duty cycle of the switch control signal of the MOS tube of the first bridge arm-the third bridge arm of the three-phase PFC circuit is fixed at a certain value, the three-phase PFC circuit is in current limiting output control mode, and the output voltage will decrease as the load increases.

[0079] In this working state, the second switch unit S5 is in a conducting state, the second ground terminal on the auxiliary circuit and the first ground terminal on the three-phase PFC circuit are conducting, but at this time, they are in a low-voltage power supply state, and the first ground terminal and the second ground terminal are electrically isolated from the third ground terminal, and there will be no safety accidents caused by the connection between the high-voltage side and the low-voltage side. Therefore, the charging and discharging system in the embodiment of the present application can achieve electrical isolation of the entire vehicle in each working mode to ensure power safety.

[0080] The charging and discharging system in this application is provided with a three-phase PFC circuit, a high-voltage isolated DC / DC circuit and an auxiliary circuit. The power battery can be charged through the charging port after AC-DC conversion, and the auxiliary circuit and the three-phase PFC circuit can be connected by controlling the switch module, so that the auxiliary battery and the low-voltage load on the auxiliary circuit are powered by the high-voltage isolated DC / DC circuit and the three-phase PFC circuit, so that emergency power supply can be provided to the load when a fault occurs on the low-voltage side to ensure vehicle safety. This application uses a switch module and a second switch unit S5, which does not require the addition of additional circuits, making it more convenient to use, and when emergency power supply is not performed, the second switch unit is always disconnected, which can achieve electrical isolation between the high-voltage side and the low-voltage side, making it safer to use.

[0081] Embodiment 2

[0082] An embodiment of the present application provides a charging and discharging system, which is applied to an electric vehicle. The circuit includes: a switch module; a power factor correction circuit; and an auxiliary battery. The power factor correction circuit can be connected to the auxiliary battery through the switch module so that the vehicle-mounted energy supply device can supply power to the auxiliary battery through the power factor correction circuit.

[0083] like Figure 8 As shown, the difference between the embodiment of the present application and the first embodiment is that the vehicle-mounted functional device in the charging and discharging system includes a power battery and a photovoltaic module.

[0084] Exemplarily, the power factor correction circuit includes at least two bridge arms, and the switch module can connect the midpoint of at least one bridge arm and the first pole of the auxiliary battery, and the busbar of the power factor correction circuit is connected to the second pole of the auxiliary battery; or, the switch module connects the midpoints of the two bridge arms and the two poles of the auxiliary battery.

[0085] The switch module includes a first switch S1 and a second switch S2, and the power factor correction circuit includes at least a first bridge arm and a second bridge arm; one end of the first switch S1 is connected to the midpoint of the first bridge arm, and the other end is switchably connected to the charging port or the first pole of the auxiliary battery; one end of the second switch S2 is connected to the midpoint of the second bridge arm, and the other end is switchably connected to the second pole of the auxiliary battery. So that the photovoltaic module supplies power to the auxiliary battery through the power factor correction circuit. Exemplarily, the power factor correction circuit also includes a third bridge arm.

[0086] The second end of the first DC / DC circuit (first conversion circuit) is also used to connect to a photovoltaic module, the positive electrode of the photovoltaic module is connected to the positive electrode of the first DC / DC circuit, and the negative electrode of the photovoltaic module is connected to the negative electrode of the first DC / DC circuit. The photovoltaic module is used to charge the power battery through the first DC / DC circuit. The first DC / DC circuit is a high-voltage isolated DC / DC circuit, and the power factor correction circuit is a three-phase PFC circuit.

[0087] Exemplarily, the switch module further includes a third switch, and the third switch includes a first sub-switch S3 and a second sub-switch S4, wherein S3 and S4 are both single-pole single-throw switches, and S1 and S2 are single-pole double-throw switches. The common end of the first switch S1 is connected to the second end of the first inductor, the first switching end of the first switch is connected to the first phase line, and the second switching end of the first switch S1 is connected to the positive pole of the auxiliary circuit. The common end of the second switch S2 is connected to the second end of the second inductor, the first switching end of the second switch S2 is connected to the second phase line, and the second switching end of the second switch S2 is connected to the negative pole of the auxiliary circuit. One end of the first sub-switch S3 is connected to the second end of the third inductor, and the other end is connected to the third phase line. The second sub-switch S4 can be connected to the negative terminal and the second end of the third inductor in an on-off manner.

[0088] The charging port is connected to a charging device or a load, and the photovoltaic module charges the power battery through the first conversion circuit; or, the photovoltaic module supplies power to the load through the power factor correction circuit and the charging port; or, the photovoltaic module supplies power to the auxiliary battery through the power factor correction circuit. The charging device connected to the charging port can also charge the power battery through the power factor correction circuit and the first conversion circuit.

[0089] In the embodiment of the present application, the power battery can be charged through the charging port after AC-DC conversion, the electric vehicle can be charged through the photovoltaic module after DC-DC conversion, and the auxiliary circuit and the three-phase PFC circuit can be controlled by the switch module to be connected, so that the auxiliary battery and the low-voltage load on the auxiliary circuit are powered by the high-voltage isolation DC / DC circuit and the three-phase PFC circuit, so that the load can be powered for emergency when a fault occurs on the low-voltage side to ensure the safety of the vehicle. Alternatively, when performing emergency power supply, the photovoltaic module can also power the auxiliary circuit through the three-phase PFC circuit. In the embodiment of the present application, the electrical isolation between the high-voltage side and the low-voltage side can be maintained, which is safer to use.

[0090] Embodiment 3

[0091] The embodiment of the present application provides a vehicle-mounted circuit system and an electric vehicle equipped with the system. The vehicle-mounted circuit system is provided with the charging and discharging system in the above embodiment. The power battery can be charged through the charging port after AC-DC conversion, and the auxiliary circuit and the power factor correction circuit can be connected through the switch module, so that the auxiliary battery and the first load (the load of the low-voltage system) on the auxiliary circuit are powered by the first DC / DC circuit and the power factor correction circuit, so that emergency power supply is provided to the load when a fault occurs on the low-voltage side to ensure the safety of the vehicle. The present application uses a switch module and a second switch unit, and there is no need to add additional circuits, so the application is more convenient, and when emergency power supply is not performed, the second switch unit is always disconnected, so that electrical isolation between the high-voltage side and the low-voltage side can be achieved, and it is safer to use.

[0092] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0093] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0094] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0095] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0096] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0097] It should be noted that the above embodiments illustrate the present application rather than limit the present application, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present application may be implemented with the aid of hardware including several different elements and with the aid of appropriately programmed computers. In a unit claim listing several on-board systems, several of these on-board systems may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.

[0098] The above is only a specific implementation or description of a specific implementation of the present application, and the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A charging and discharging system, applied to electric vehicles, characterized in that: The system comprises: Switch module; Power factor correction circuit; Auxiliary battery, the power factor correction circuit is connected to the auxiliary battery in an on-off manner through the switch module, so that the vehicle-mounted energy supply device supplies power to the auxiliary battery through the power factor correction circuit.

2. The charging and discharging system according to claim 1, characterized in that: The power factor correction circuit includes at least one bridge arm, and the switch module can connect the midpoint of the bridge arm of the power factor correction circuit and the auxiliary battery to enable the vehicle-mounted energy supply device to supply power to the auxiliary battery through the power factor correction circuit.

3. The charging and discharging system according to claim 1, characterized in that: The power factor correction circuit includes at least two bridge arms, and the switch module can connect the midpoint of at least one of the bridge arms and the first pole of the auxiliary battery, and the busbar of the power factor correction circuit is connected to the second pole of the auxiliary battery; or, the switch module connects the midpoints of two bridge arms and the two poles of the auxiliary battery.

4. The charging and discharging system according to claim 2, characterized in that: The switch module comprises: a first switch unit and a second switch unit, wherein the first switch unit can be switched on and off to connect the midpoint of the bridge arm and the first pole of the auxiliary battery, and the second switch unit can be switched on and off to connect the second pole of the auxiliary battery and the busbar of the power factor correction circuit; The switch module is configured as follows: the first switch unit connects at least one midpoint of the bridge arm to the first pole of the auxiliary battery, and the second switch unit connects the busbar of the power factor correction circuit to the second pole of the auxiliary battery, so that the vehicle-mounted energy supply device supplies power to the auxiliary battery through the power factor correction circuit.

5. The charging and discharging system according to claim 4, characterized in that: The first switch unit includes: a first switch, a second switch and a third switch; the power factor correction circuit includes a first bridge arm, a second bridge arm and a third bridge arm; One end of the first switch is connected to the midpoint of the first bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery; one end of the second switch is connected to the midpoint of the second bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery; one end of the third switch is connected to the midpoint of the third bridge arm, and the other end is connected to the charging port or the first pole of the auxiliary battery.

6. The charging and discharging system according to claim 5, characterized in that: The vehicle-mounted energy supply device includes a power battery, and the system also includes a first conversion circuit, a first end of the first conversion circuit is connected to the power battery, and a second end of the first conversion circuit is connected to the power factor correction circuit.

7. The charging and discharging system according to claim 3, characterized in that: The switch module includes a first switch and a second switch, and the power factor correction circuit includes at least a first bridge arm and a second bridge arm; One end of the first switch is connected to the midpoint of the first bridge arm, and the other end can be switchably connected to the charging port or the first pole of the auxiliary battery; one end of the second switch is connected to the midpoint of the second bridge arm, and the other end can be switchably connected to the second pole of the auxiliary battery.

8. The charging and discharging system according to claim 7, characterized in that: The vehicle-mounted energy supply device includes a power battery and a photovoltaic component. The system also includes a first conversion circuit, a first end of the first conversion circuit is connected to the power battery, and a second end of the first conversion circuit and the photovoltaic component are both connected to the power factor correction circuit.

9. The charging and discharging system according to claim 8, characterized in that: The charging port is connected to a charging device or a load; The photovoltaic assembly charges the power battery through the first conversion circuit; Alternatively, the photovoltaic assembly supplies power to the load via the power factor correction circuit and the charging port; Alternatively, the photovoltaic assembly supplies power to the auxiliary battery through the power factor correction circuit.

10. The charging and discharging system according to claim 6, characterized in that: The charging port is connected to a charging device or a load; The switch module may also be configured to: connect the charging port and the power factor correction circuit, so that the charging device charges the power battery through the charging port, the power factor correction circuit and the first conversion circuit; or, The power battery supplies power to the load through the first conversion circuit, the power factor correction circuit and the charging port.

11. The charging and discharging system according to claim 10, characterized in that: The charging port includes a first phase line, a second phase line, a third phase line and a negative terminal, and the power factor correction circuit also includes a first inductor, a second inductor and a third inductor, the first inductor is connected to the midpoint of the first bridge arm, the second inductor is connected to the midpoint of the second bridge arm, and the third inductor is connected to the midpoint of the third bridge arm; A first end of the first switch is connected to the first inductor, and a second end of the first switch is switchably connected to the first phase line or the first pole of the auxiliary battery; A first end of the second switch is connected to the second inductor, and a second end of the second switch is switchably connected to the second phase line or the first pole of the auxiliary battery; The third switch includes a first sub-switch and a second sub-switch, the first end of the first sub-switch is connected to the third inductor, and the second end of the first sub-switch can be switchably connected to the third phase line or the first pole of the auxiliary battery; the third inductor is connected to the negative terminal in a switching manner through the second sub-switch.

12. The charging and discharging system according to claim 11, characterized in that: The charging port is connected to a charging device, and the switch module is configured as follows: one of the first switch, the second switch, and the third switch is connected to the charging port and the power factor correction circuit, the second sub-switch is closed, and the second switch unit is opened; The charging device performs single-phase inverter charging for the power battery through the charging port, the power factor correction circuit and the first conversion circuit.

13. The charging and discharging system according to claim 11, characterized in that: The charging port is connected to a load, and the switch module is configured as follows: one of the first switch, the second switch, and the third switch is connected to the charging port and the power factor correction circuit, the second sub-switch is closed, and the second switch unit is opened; The power battery supplies power to the load through the first conversion circuit, the power factor correction circuit and the charging port.

14. The charging and discharging system according to claim 11, characterized in that: The charging port is connected to a charging device, and the switch module is configured as follows: the first switch, the second switch, and the third switch are all connected to the charging port and the power factor correction circuit, the second sub-switch is disconnected, and the second switch unit is disconnected; The charging device performs three-phase inverter charging for the power battery through the charging port, the power factor correction circuit and the first conversion circuit.

15. The charging and discharging system according to claim 11, characterized in that: The charging port is connected to a load, and the switch module is configured as follows: the first switch, the second switch, and the third switch are all connected to the charging port and the power factor correction circuit, the second sub-switch is disconnected, and the second switch unit is disconnected; The power battery supplies power to the load through the first conversion circuit, the power factor correction circuit and the charging port.

16. The charging and discharging system according to claim 11, characterized in that: The switch module is configured as follows: the first switch, the second switch and the third switch are all connected to the first pole of the auxiliary battery and the power factor correction circuit, the second sub-switch is disconnected, and the second switch unit is closed to connect the second pole of the auxiliary battery and the busbar of the power factor correction circuit; The power battery supplies power to the auxiliary battery through the first conversion circuit and the power factor correction circuit.

17. The charging and discharging system according to any one of claims 8 to 16, further comprising a second conversion circuit, wherein the second conversion circuit is connected to the vehicle-mounted energy supply device and the auxiliary battery to supply power to the auxiliary battery; The switch module is configured to connect the power factor correction circuit and the auxiliary battery when the second conversion circuit fails, so that the vehicle-mounted energy supply device supplies power to the auxiliary battery through the first conversion circuit and the power factor correction circuit.

18. A vehicle-mounted power supply, characterized in that: The on-vehicle power supply includes the charging and discharging system according to any one of claims 1-17.

19. An electric vehicle, characterized in that: The electric vehicle includes the on-board power supply according to claim 18.

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