Single-phase on-board charger, control method thereof, and electric vehicle comprising same

Abstract

The application provides a single-phase vehicle charger, a control method thereof, and an electric vehicle comprising the same. In the process of working in an off-grid mode, the single-phase PFC circuit bus capacitor bus voltage is determined whether it is greater than the bus voltage set value. If yes, and the duration is greater than the first set value, the current reference of the single-phase PFC circuit current control loop is adjusted, so that the single-phase PFC circuit bus capacitor releases the electric energy. If no, the single-phase vehicle charger continues to work in the off-grid mode. In the process of releasing the electric energy of the single-phase PFC circuit bus capacitor, if the grid-connected instruction signal is received, the single-phase vehicle charger works in the grid-connected mode. If no, whether the duration is greater than the second set value is determined. If yes, the single-phase vehicle charger is shut down. If no, the single-phase PFC circuit bus capacitor releases the electric energy. The error or even shutdown failure caused by triggering the bus capacitor overvoltage during the off-grid to grid-connected switching can be avoided.

Description

Technical Field

[0001] This application relates to the field of power supply, and in particular to single-phase on-board chargers, control methods thereof, and electric vehicles including such chargers. Background Technology

[0002] With the development of technology and market demand, electric vehicles are becoming increasingly popular.

[0003] Currently, electric vehicles on the market typically include a high-voltage battery unit and a bidirectional single-phase on-board charger. When the bidirectional single-phase on-board charger is working in charging mode, it can convert AC power into DC power to charge the high-voltage battery unit. When working in inverter grid-connected mode, it can convert the electrical energy of the high-voltage battery unit into AC power to regulate the power grid. When working in off-grid mode, it can convert the electrical energy of the high-voltage battery unit into electrical energy to power the loads on the electric vehicle (such as on-board refrigerators).

[0004] In practical applications, both the bidirectional single-phase on-board charger operating in charging mode and the inverter grid-connected mode are usually referred to as operating in grid-connected mode.

[0005] Off-grid / grid mode switching, that is, switching from off-grid mode to grid-connected mode, is an essential function of current single-phase vehicle-mounted chargers. Typically, when a bidirectional single-phase vehicle-mounted charger is operating in off-grid mode, an external power grid connection is suddenly established, causing the bidirectional single-phase vehicle-mounted charger to operate in charging mode or inverter grid-connected mode.

[0006] Single-phase on-board chargers are currently the most commonly used type of bidirectional single-phase on-board charger. Please refer to [link / reference]. Figure 1 The diagram shows a typical main circuit structure of a single-phase on-board charger, which includes a cascaded single-phase PFC circuit 100 and a bidirectional DC / DC converter 200. The first DC terminal of the bidirectional DC / DC converter 200 is connected to the DC terminal of the single-phase PFC circuit 100, and the second DC terminal of the bidirectional DC / DC converter 200 is connected to the high-voltage battery unit HV. The AC terminal of the single-phase PFC circuit 100 is used to charge the loads on the electric vehicle (such as...). Figure 1 The resistive load (RL) in the circuit is powered by the circuit or connected to the AC power grid, wherein the single-phase PFC circuit 100 is a bidirectional PFC circuit.

[0007] Therefore, it can be seen that the AC port of a typical single-phase on-board charger in both grid-connected and off-grid modes is the same port, which is... Figure 1 Ports AC1-AC2 in the diagram.

[0008] for Figure 1The typical single-phase on-board charger shown can proactively disconnect from the grid and shut down after receiving a grid connection command from the customer, before reconnecting. This grid connection method is called proactive grid connection. This method requires the single-phase on-board charger to shut down, which is undesirable for customers.

[0009] for Figure 1 The typical single-phase on-board charger shown can also be manually connected to the grid in off-grid mode (e.g., by suddenly plugging in the charging gun) to achieve grid connection; we call this grid connection method passive grid connection. However, because there may be a phase difference between the AC voltage phase output by the single-phase on-board charger and the grid voltage phase in off-grid mode, please refer to [link to relevant documentation]. Figure 2 shown Figure 1 This diagram illustrates a typical single-phase on-board charger switching between off-grid and grid-connected modes, showing the AC port voltage transition. The sine wave labeled 210 represents the output voltage waveform in off-grid mode, and the sine wave labeled 220 represents the AC grid voltage waveform. Assuming a voltage transition occurs at time t1 when the charger is connected to the grid, as shown... Figure 2 As shown, due to the sudden decrease in port voltage, the voltage loop calculation result of the single-phase on-board charger will increase rapidly, resulting in an increase in the duty cycle of the switching transistor in the single-phase PFC circuit 100. In other words, energy will be instantaneously transferred from the grid to the internal circuit of the single-phase on-board charger, which in turn causes the voltage on the bus capacitor Cbulk at the DC end of the single-phase PFC circuit 100 to rise rapidly. This may eventually trigger a bus overvoltage fault or damage the switching transistor in the single-phase PFC circuit 100, leading to errors or even shutdown, and preventing normal grid connection.

[0010] Errors or shutdowns are undesirable for customers, meaning the current solution cannot complete the on-grid switching of single-phase vehicle chargers, resulting in poor product performance and a poor customer experience.

[0011] Therefore, how to ensure that single-phase on-board chargers can switch between on-grid and off-grid without errors or shutdowns, and achieve normal and rapid on-grid switching, has become a technical problem that the industry urgently needs to solve. Summary of the Invention

[0012] According to one embodiment, this application provides a control method for a single-phase on-board charger, wherein the single-phase on-board charger includes a single-phase PFC circuit, the single-phase PFC circuit being a bidirectional PFC circuit, comprising: S10: the controller controls the single-phase on-board charger to operate in off-grid mode; S20: determining whether the bus voltage of the bus capacitor of the single-phase PFC circuit is greater than a set bus voltage value; if yes, proceed to step S40; if no, proceed to step S10; S40: determining whether the duration is greater than a first set value; if yes, proceed to step S50; if no, proceed to step S10; S50: determining the current reference value of the current control loop of the single-phase PFC circuit based on the real-time AC voltage signal at the AC terminal of the single-phase PFC circuit, so that the switching control signal output by the controller controls the bus capacitor of the single-phase PFC circuit to release electrical energy; S60: determining whether a grid-connected mode operating command is received; if yes, proceed to step S80; if no, proceed to step S70. S80: The controller controls the single-phase on-board charger to work in grid-connected mode; S70: Determine whether the duration is greater than the second set value. If yes, proceed to the shutdown step S90; otherwise, proceed to step S50.

[0013] Furthermore, in step S50, the first proportional unit in the controller multiplies the real-time AC voltage signal at the AC terminal of the single-phase PFC circuit with a first proportional coefficient to obtain a first current reference value, which is used as the current reference value of the current control loop of the single-phase PFC circuit; the third calculation unit in the controller receives the first current reference value, the output current value at the AC terminal of the single-phase PFC circuit, and the inductance current flowing through the inductor at the AC terminal of the single-phase PFC circuit, and outputs a first current indication signal; the control signal generation unit in the controller outputs a switch control signal according to the first current indication signal, causing the bus capacitor of the single-phase PFC circuit to release electrical energy.

[0014] Furthermore, in step S10, the first calculation unit within the controller receives the real-time AC voltage signal and the set AC voltage value from the AC terminal of the single-phase PFC circuit, and outputs the AC voltage difference; the first compensation unit within the controller obtains a second current reference value based on the AC voltage difference; the second calculation unit within the controller receives the second current reference value, the output current value from the AC terminal of the single-phase PFC circuit, and the inductance current flowing through the inductor at the AC terminal of the single-phase PFC circuit, and outputs a second current indication signal; the control signal generation unit within the controller outputs a switch control signal based on the second current indication signal, causing the single-phase on-board charger to operate in off-grid mode.

[0015] Furthermore, step S60 includes: step S61: determining whether an inverter grid-connected mode operating command has been received, and step S62: determining whether a charging mode operating command has been received; step S80 includes: step S81: the controller controls the single-phase on-board charger to operate in inverter grid-connected mode, and step S82: the controller controls the single-phase on-board charger to operate in charging mode; wherein, step S61 is executed after step S50. If the determination result of step S61 is negative, proceed to step S62; if the determination result of step S61 is positive, proceed to step S81; if the determination result of step S62 is negative, proceed to step S70; if the determination result of step S62 is positive, proceed to step S82.

[0016] Furthermore, in step S81, the second proportional unit in the controller receives the inverter grid-connected command signal from the vehicle and outputs a current indication signal; the phase-locked unit receives the real-time AC voltage signal from the AC terminal of the single-phase PFC circuit and outputs a phase-locked indication signal; the fourth calculation unit receives the current indication signal and the phase-locked indication signal and outputs a third current reference value; the fifth calculation unit receives the third current reference value, the output current value of the AC terminal of the single-phase PFC circuit, and the inductance current flowing through the inductor of the AC terminal of the single-phase PFC circuit, and outputs a third current indication signal; the control signal generation unit in the controller outputs a switch control signal according to the third current indication signal, so that the single-phase on-board charger operates in inverter grid-connected mode.

[0017] Furthermore, in step S82, the sixth calculation unit in the controller receives the bus voltage feedback signal of the bus capacitor of the single-phase PFC circuit and the bus voltage set value, and outputs the bus voltage difference; the second compensation unit receives the bus voltage difference and outputs the fourth current reference value; the seventh calculation unit receives the fourth current reference value and the inductance current flowing through the inductor of the AC terminal of the single-phase PFC circuit, and outputs the third current indication signal; the control signal generation unit in the controller outputs a switch control signal according to the third current indication signal, so that the single-phase on-board charger works in charging mode.

[0018] This application also provides a single-phase on-board charger, comprising: a single-phase PFC circuit, the single-phase PFC circuit including a switching transistor unit, the switching transistor unit including at least one switching transistor, an inductor connected between the switching transistor unit and the AC terminal of the single-phase PFC circuit, the switching transistor unit being connected in parallel with a bus capacitor to form the DC terminal of the single-phase PFC circuit, the AC terminal of the single-phase PFC circuit being used to supply power to a load or connect to the power grid; a controller, comprising: a judgment unit, configured to receive the bus voltage on the bus capacitor and a bus voltage set value, and output a judgment indication signal; a first control unit, configured to determine the current reference value of the current control loop of the single-phase PFC circuit based on the real-time AC voltage signal of the AC terminal of the single-phase PFC circuit when the judgment indication signal indicates that the bus voltage on the bus capacitor is greater than the bus voltage set value and the duration is greater than the first set value, and output a first current indication signal; and a control signal generation unit, configured to output a switch control signal based on the first current indication signal, and control the bus capacitor of the single-phase PFC circuit to release electrical energy.

[0019] Furthermore, the first control unit includes: a first proportional unit, used to multiply the real-time AC voltage signal at the AC terminal of the single-phase PFC circuit with a first proportional coefficient to obtain a first current reference value, which is used as the current reference value of the current control loop of the single-phase PFC circuit; and a third calculation unit, used to receive the first current reference value, the output current value at the AC terminal of the single-phase PFC circuit, and the inductor current flowing through the inductor, and output the first current indication signal.

[0020] Furthermore, the controller also includes an off-grid mode control unit, which includes: a first calculation unit for receiving the real-time AC voltage signal and AC voltage set value of the AC terminal of the single-phase PFC circuit, and outputting an AC voltage difference; a first compensation unit for obtaining a second current reference value based on the AC voltage difference; a second calculation unit for receiving the second current reference value, the output current value of the AC terminal of the single-phase PFC circuit, and the inductor current flowing through the inductor, and outputting a second current indication signal; and a selection unit for receiving the first current indication signal and the second current indication signal. When the bus voltage on the bus capacitor of the single-phase PFC circuit is greater than the bus voltage set value and the duration is greater than the first set value, the selection unit outputs the first current indication signal to the control signal generation unit; when the bus voltage on the bus capacitor of the single-phase PFC circuit is less than the bus voltage set value, the selection unit outputs the second current indication signal to the control signal generation unit to control the single-phase on-board charger to operate in off-grid mode.

[0021] Furthermore, the controller also includes a grid-connected mode control unit, which receives a grid-connected indication signal and outputs a third current indication signal to the selection unit according to the grid-connected indication signal. When the selection unit receives the third current indication signal, the selection unit outputs the third current indication signal to the control signal generation unit. The switch control signal generated by the control signal generation unit causes the single-phase on-board charger to operate in grid-connected mode.

[0022] Furthermore, the grid-connected mode control unit includes an inverter grid-connected mode control unit, comprising: a second proportional unit, used to receive the inverter grid-connected command signal from the vehicle and output a current indication signal; a phase-locked unit, used to receive the real-time AC voltage signal from the AC terminal of the single-phase PFC circuit and output a phase-locked indication signal; a fourth calculation unit, used to receive the current indication signal and the phase-locked indication signal and output a third current reference value; and a fifth calculation unit, used to receive the third current reference value, the output current value from the AC terminal of the single-phase PFC circuit, and the inductor current flowing through the inductor, and output a third current indication signal. When the selection unit receives the third current indication signal, the selection unit outputs the third current indication signal to the control signal generation unit. The switching control signal generated by the control signal generation unit causes the single-phase on-board charger to operate in inverter grid-connected mode.

[0023] Furthermore, the grid-connected mode control unit includes a charging mode control unit, comprising: a sixth calculation unit, used to receive the bus voltage feedback signal of the bus capacitor of the single-phase PFC circuit and the bus voltage set value, and output the bus voltage difference; a second compensation unit, used to receive the bus voltage difference and output a fourth current reference value; a seventh calculation unit, used to receive the fourth current reference value and the inductor current flowing through the inductor, and output a third current indication signal. When the selection unit receives the third current indication signal, the selection unit outputs the third current indication signal to the control signal generation unit. The switch control signal generated by the control signal generation unit causes the single-phase on-board charger to operate in charging mode.

[0024] Furthermore, it also includes a bidirectional DC / DC converter, the first DC terminal of which is connected to the DC terminal of the single-phase PFC circuit, and the second DC terminal of which is connected to the high-voltage battery unit.

[0025] Furthermore, during the process of the off-grid mode control unit controlling the single-phase on-board charger to operate in off-grid mode, the judgment unit determines whether the bus voltage on the bus capacitor is greater than the bus voltage set value. If so, and the duration is greater than the first set value, the first control unit controls the bus capacitor of the single-phase PFC circuit to release energy. If not, the off-grid mode control unit controls the single-phase on-board charger to continue operating in off-grid mode. During the process of the bus capacitor of the single-phase PFC circuit releasing energy, if a grid connection indication signal is received, the single-phase on-board charger is made to operate in grid connection mode. If not, it is determined whether the duration is greater than the second set value. If so, the charger is turned off. If not, the first control unit controls the bus capacitor of the single-phase PFC circuit to release energy.

[0026] This application also provides an electric vehicle, including the single-phase on-board charger described above. Attached Figure Description

[0027] To gain a more complete understanding of this disclosure and its advantages, the following description is given in conjunction with the accompanying drawings, wherein:

[0028] Figure 1 This is a schematic diagram of a typical single-phase on-board charger main circuit structure;

[0029] Figure 2 for Figure 1 A typical diagram illustrating the AC port voltage transition of a single-phase on-board charger switching between off-grid and grid-connected modes.

[0030] Figure 3 A flowchart of a control method for a single-phase on-board charger according to an embodiment of this application is shown;

[0031] Figure 4 A schematic diagram of a single-phase on-board charger according to an embodiment of this application is shown;

[0032] Figure 5 A flowchart of a single-phase on-board charger grid-connected mode control method according to an embodiment of this application is shown;

[0033] Figure 6 A schematic diagram of a single-phase on-board charger according to an embodiment of this application is shown;

[0034] Figure 7 A schematic diagram of a single-phase on-board charger according to an embodiment of this application is shown;

[0035] Figure 8 A schematic diagram of a single-phase on-board charger according to an embodiment of this application is shown.

[0036] Unless otherwise stated, corresponding numbers and symbols in the various figures generally refer to corresponding parts. These figures are drawn to clearly illustrate relevant aspects of the various embodiments and are not necessarily drawn to scale. Detailed Implementation

[0037] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] One embodiment of this application provides a control method for a single-phase on-board charger. The main circuit of this single-phase on-board charger can be found in [reference needed]. Figure 1 .

[0039] like Figure 1 The single-phase on-board charger shown can operate in off-grid mode, in which it converts the electrical energy from the high-voltage battery unit into electrical energy to power loads on the electric vehicle (such as an onboard refrigerator). Figure 1 As shown, the resistive load RL is powered at ports AC1-AC2. At this time, the bidirectional DC / DC converter 200 converts the DC power from the high-voltage battery unit HV at its second DC terminal to the DC power at its first DC terminal, and the single-phase PFC circuit 100 converts the DC power at its DC terminal to the AC power at its AC terminal to power the load RL.

[0040] like Figure 1 The single-phase on-board charger shown can also operate in inverter grid-connected mode, in which the electrical energy of the high-voltage battery unit HV is converted into AC power to regulate the power grid, that is, ports AC1-AC2 are connected to the power grid (AC source). At this time, the bidirectional DC / DC converter 200 converts the DC power of the high-voltage battery unit HV at its second DC terminal into the DC power of its first DC terminal, and the single-phase PFC circuit 100 converts the DC power at its DC terminal into the AC power at its AC terminal to connect to the power grid.

[0041] like Figure 1 The single-phase on-board charger shown can also operate in charging mode, in which it converts the AC power from the grid into DC power to charge the high-voltage battery unit HV. At this time, the single-phase PFC circuit 100 converts the AC power at its AC terminal into the DC power at its DC terminal, and the bidirectional DC / DC converter 200 converts the DC power at its first DC terminal into the DC power at its second DC terminal to charge the high-voltage battery unit HV.

[0042] Since single-phase on-board chargers are connected to the power grid (AC source) in both charging mode and inverter grid-connected mode, the operation of bidirectional single-phase on-board chargers in both charging mode and inverter grid-connected mode is usually referred to as operating in grid-connected mode. The mode in which power is supplied to the load RL is called off-grid mode.

[0043] As mentioned above, the AC port for both off-grid mode and grid-connected mode is the same port, which is... Figure 1 Ports AC1-AC2 in the circuit. As described in the prior art, when suddenly plugged into the grid in off-grid mode, i.e., when passively connected to the grid, the voltage on the bus capacitor Cbulk at the DC end of the single-phase PFC circuit 100 will rise rapidly, which may eventually trigger a bus overvoltage fault or damage the switching transistor in the single-phase PFC circuit 100, resulting in errors or even shutdown, and thus failing to connect to the grid normally.

[0044] For details, please refer to [link / reference]. Figure 1 The single-phase PFC circuit 100 may include a switching transistor unit 110, which includes at least one switching transistor. An inductor L1 is connected between the switching transistor unit 110 and the AC terminals AC1-AC2 of the single-phase PFC circuit 100. The switching transistor unit 110 is connected in parallel with a bus capacitor Cbulk to form the DC terminal of the single-phase PFC circuit 100. The AC terminals AC1-AC2 of the single-phase PFC circuit 100 are used to supply power to the load RL or connect to the power grid (AC source).

[0045] like Figure 1 As shown, a capacitor C1 is usually connected between the first AC terminal AC1 and the second AC terminal AC2.

[0046] We call the current flowing through inductor L1 the inductor current IL, and the current flowing out of the AC terminal of the single-phase PFC circuit 100 the output current IoAC.

[0047] Please refer to the following: Figure 1 The switching transistor unit 110 includes: a first switching branch formed by a first switching transistor S1 and a second switching transistor S2 connected in series, and a second switching branch formed by a third switching transistor S3 and a fourth switching transistor S4 connected in series. The first and second switching branches are connected in parallel and then connected in parallel with the bus capacitor Cbulk. At least one of the common node of the two switching transistors in the first switching branch and the common node of the two switching transistors in the second switching branch is connected to the AC terminal of the single-phase PFC circuit 100 through an inductor, such as... Figure 1 As shown, the common node of the two switching transistors in the first switching branch is connected to the first AC terminal AC1 of the single-phase PFC circuit 100 through inductor L1, and the common node of the two switching transistors in the second switching branch is connected to the second AC terminal AC2 of the single-phase PFC circuit 100.

[0048] This application does not limit the specific structure of the switching transistor unit 110 or the number of inductors. As long as the single-phase PFC circuit 100 can convert the AC power at its AC terminal to the DC power at its DC terminal, and can convert the DC power at its DC terminal to the AC power at its AC terminal, that is, implement a bidirectional PFC circuit, it is acceptable.

[0049] This application does not limit the specific structure of the bidirectional DC / DC converter 200, as long as it can realize the bidirectional conversion function, such as a full-bridge converter.

[0050] for Figure 1 The single-phase on-board charger shown has the same off-grid port as the grid-connected port. This application provides a control method, which can be found in the following reference. Figure 3 The flowchart of the control method for a single-phase on-board charger is shown below, and can be consulted. Figure 4 The schematic diagram shown is of a single-phase on-board charger according to an embodiment of this application. The single-phase on-board charger includes... Figure 1 The single-phase on-board charger main circuit 10 and controller 20 shown are illustrated. The DC terminal of the single-phase on-board charger main circuit 10 is connected to the high-voltage battery unit HV, and the AC terminal of the single-phase on-board charger main circuit 10 is used to connect to the power grid or load. It includes:

[0051] S10: Controller 20 controls the single-phase on-board charger to operate in off-grid mode;

[0052] S20: Determine whether the bus voltage of the bus capacitor Cbulk of the single-phase PFC circuit 100 is greater than the bus voltage setting value Cbulk_s. If yes, proceed to step S40; otherwise, proceed to step S10.

[0053] S40: Determine whether the duration is greater than the first set value. If yes, proceed to step S50; otherwise, proceed to step S10.

[0054] S50: Based on the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit 100, determine the current reference value of the current control loop of the single-phase PFC circuit, so that the controller outputs an open circuit...

[0055] The off control signal causes the bus capacitor Cbulk of the single-phase PFC circuit to release electrical energy.

[0056] S60: Determine whether a grid-connected mode working command has been received. If yes, proceed to step S80; otherwise, proceed to step S70.

[0057] S80: The controller 20 controls the single-phase on-board charger to operate in grid-connected mode;

[0058] S70: Determine whether the duration is greater than the second set value. If yes, proceed to the shutdown step S90; otherwise, proceed to step S50.

[0059] Thus, in off-grid mode, if the bus voltage Vbulk on the bus capacitor Cbulk of the single-phase PFC circuit 100 exceeds the set bus voltage value Vbulk_s, it may be due to a sudden connection to the grid at the AC port. The current reference value of the current control loop of the single-phase PFC circuit 100 is immediately adjusted to be determined based on the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit. This allows the output current of the single-phase PFC circuit 100 to quickly follow the connected grid voltage and ensures that the bus capacitor Cbulk of the single-phase PFC circuit 100 releases energy, i.e., the energy of the bus capacitor Cbulk is transferred outward (to the grid), preventing energy from flowing back into the bus capacitor Cbulk. This avoids triggering overvoltage on the bus capacitor or damage to the switching transistors within the single-phase PFC circuit 100, which could lead to errors or even shutdown. Afterward, based on the received actual grid-connected mode operating command, the circuit operates in the corresponding grid-connected mode. In other words, this application can achieve grid connection without shutdown or error reporting, improving product performance and customer experience.

[0060] In addition, this application can complete the fast passive switching function between grid connection and off-grid connection of a single-phase on-board charger simply by changing the software control strategy. The logic is clear, and no hardware circuit modification is required, resulting in low cost.

[0061] Furthermore, in step S50, the first proportional unit 320 in the controller 20 multiplies the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit with the first proportional coefficient km1 to obtain the first current reference value Iref1, which is used as the current reference value of the current control loop of the single-phase PFC circuit 100.

[0062] The third calculation unit 330 in the controller 20 receives the first current reference value Iref1, the output current value IoAC of the AC terminal of the single-phase PFC circuit, and the inductance current IL of the inductor flowing through the AC terminal of the single-phase PFC circuit, and outputs the first current indication signal Is1.

[0063] The control signal generation unit 390 in the controller 20 outputs a switch control signal according to the first current indication signal Is1, so that the bus capacitor Cbulk of the single-phase PFC circuit 100 releases electrical energy.

[0064] That is, the current reference value of the control loop of the single-phase PFC circuit 100 is determined based on the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit, so that the output current of the single-phase PFC circuit 100 can quickly follow the grid voltage connected to it, preventing energy from flowing back to the bus capacitor Cbulk, avoiding triggering overvoltage of the bus capacitor or damage to the switching transistor in the single-phase PFC circuit 100.

[0065] Furthermore, in step S10, the first calculation unit 340 within the controller 20 receives the real-time AC voltage signal Vac and the AC voltage setpoint Vac_s from the AC terminal of the single-phase PFC circuit, and outputs the AC voltage difference Vs.

[0066] The first compensation unit 350 in the controller 20 obtains the second current reference value Iref2 based on the AC voltage difference Vs;

[0067] The second calculation unit 360 within the controller 20 receives the second current reference value Iref2, the output current value IoAC of the AC terminal of the single-phase PFC circuit, and the inductor current IL flowing through the inductor L1 of the AC terminal of the single-phase PFC circuit, and outputs the second current indication signal Is2.

[0068] The control signal generation unit 390 in the controller 20 outputs a switch control signal according to the second current indication signal Is2, so that the single-phase on-board charger works in off-grid mode.

[0069] That is, when the single-phase on-board charger is working in off-grid mode, the voltage outer loop determines the current reference value of the current inner loop.

[0070] For further details, please refer to Figure 5 The flowchart of the single-phase on-board charger grid-connected mode control method shown above refers to both the inverter grid-connected mode and the charging mode as grid-connected mode. Step S60 includes: Step S61: Determine whether an inverter grid-connected mode operating command has been received, and Step S62: Determine whether a charging mode operating command has been received.

[0071] Step S80 includes: Step S81: The controller controls the single-phase on-board charger to operate in inverter grid-connected mode, and Step S82: The controller controls the single-phase on-board charger to operate in charging mode.

[0072] Specifically, after step S50, step S61 is executed. If the judgment result of step S61 is negative, step S62 is executed. If the judgment result of step S61 is positive, step S81 is executed. If the judgment result of step S62 is negative, step S70 is executed. If the judgment result of step S62 is positive, step S82 is executed.

[0073] That is, the single-phase on-board charger is controlled to operate in the corresponding grid-connected mode according to the received actual grid-connected mode operation command. When an inverter grid-connected mode operation command is received, the single-phase on-board charger is controlled to operate in inverter grid-connected mode; when a charging mode operation command is received, the single-phase on-board charger is controlled to operate in charging mode.

[0074] Thus, this application can accommodate both off-grid to grid-connected inverter and off-grid to grid-connected charging modes, covering all working modes of single-phase on-board chargers.

[0075] Furthermore, in step S81, the second proportional unit 381 in the controller 20 receives the inverter grid connection command signal Icmd from the whole vehicle and outputs the current indication signal Isc.

[0076] Phase-locked unit 383 receives the real-time AC voltage signal Vac from the AC terminal of the single-phase PFC circuit and outputs a phase-locked indication signal θ.

[0077] The fourth calculation unit 382 receives the current indication signal Isc and the phase-locked signal θ, and outputs the third current reference value Iref3;

[0078] The fifth calculation unit 384 receives the third current reference value Iref3, the output current value IoAC of the AC terminal of the single-phase PFC circuit, and the inductance current IL of the inductor flowing through the AC terminal of the single-phase PFC circuit, and outputs the third current indication signal Is31.

[0079] The control signal generation unit 390 in the controller 20 outputs a switch control signal according to the third current indication signal Is31, so that the single-phase on-board charger operates in inverter grid-connected mode.

[0080] At this time, the switch control signal controls the single-phase PFC circuit 100 to invert the DC power on the bus capacitor Cbulk into AC power that is connected to the power grid.

[0081] Furthermore, in step S82, the sixth calculation unit 385 in the controller 20 receives the bus voltage feedback signal Vbulk_f of the bus capacitor Cbulk of the single-phase PFC circuit 100 and the bus voltage setting value Vbulk_set, and outputs the bus voltage difference Vbc.

[0082] The second compensation unit 386 receives the bus voltage difference Vbc and outputs the fourth current reference value Iref4.

[0083] The seventh calculation unit 387 receives the fourth current reference value Iref4 and the inductor current IL flowing through the inductor at the AC terminal of the single-phase PFC circuit, and outputs the third current indication signal Is32.

[0084] The control signal generation unit 390 in the controller 20 outputs a switch control signal according to the third current indication signal Is32, so that the single-phase on-board charger works in charging mode.

[0085] At this time, the switch control signal controls the single-phase PFC circuit 100 to convert the AC power from the grid into DC power on the bus capacitor Cbulk.

[0086] The control method for the single-phase on-board charger described in this application can avoid the energy backflow into the bus capacitor Cbulk of the single-phase PFC circuit 100 due to a sudden artificial connection to the grid during the operation of the single-phase on-board charger in off-grid mode. This would prevent overvoltage of the bus capacitor or damage to the switching transistor in the single-phase PFC circuit 100. The method can achieve rapid on-grid switching without errors or shutdown, and can also handle both off-grid switching to inverter grid connection and off-grid switching to high-voltage battery unit charging.

[0087] This application also provides a single-phase on-board charger, details of which can be found in [reference needed]. Figure 6 The schematic diagram of a single-phase on-board charger according to an embodiment of this application shown includes:

[0088] A single-phase PFC circuit 100 includes a switching transistor unit 110, which contains at least one switching transistor. An inductor L1 is connected between the switching transistor unit 110 and the AC terminals AC1-AC2 of the single-phase PFC circuit 100. The switching transistor unit 110 is connected in parallel with a bus capacitor Cbulk to form the DC terminal of the single-phase PFC circuit 100. The AC terminals AC1-AC2 of the single-phase PFC circuit 100 are used to supply power to the load RL or connect to the power grid (AC source).

[0089] Controller 20, including:

[0090] Judgment unit 310 is used to receive the bus voltage Vbulk on the bus capacitor Cbulk and the bus voltage setting value Vbulk_s, and output judgment indication signal Cs;

[0091] The first control unit 21 is configured to determine the current reference value of the current control loop of the single-phase PFC circuit based on the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit when the judgment indication signal Cs indicates that the bus voltage Vbulk on the bus capacitor is greater than the bus voltage setting value Vbulk_s and the duration is greater than the first setting value, and output the first current indication signal Is1.

[0092] The control signal generation unit 390 is used to output a switch control signal according to the first current indication signal Is1, and control the bus capacitor Cbulk of the single-phase PFC circuit 100 to release electrical energy.

[0093] When the bus voltage on the bus capacitor Cbulk of the single-phase PFC circuit 100 exceeds the set bus voltage value Vbulk_s, it may be due to a sudden connection to the grid at the AC port. The current loop reference of the control circuit of the single-phase PFC circuit 100 is immediately adjusted to be determined based on the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit. This allows the output current of the single-phase PFC circuit 100 to quickly follow the connected grid voltage and ensures that the bus capacitor Cbulk of the single-phase PFC circuit 100 releases energy, i.e., the energy of the bus capacitor Cbulk is transferred outward (to the grid), preventing energy from flowing back into the bus capacitor Cbulk. This avoids triggering overvoltage on the bus capacitor or damage to the switching transistors within the single-phase PFC circuit 100, which could lead to errors or even shutdown. Afterward, based on the received actual grid connection mode operating command, the circuit operates in the corresponding grid connection mode. In other words, this application can achieve grid connection without shutdown or error reporting, improving product performance and customer experience.

[0094] In addition, this application can complete the fast passive switching function between grid connection and off-grid connection of a single-phase on-board charger simply by changing the software control strategy of the controller 20. The logic is clear and no hardware circuit modification is required, resulting in low cost.

[0095] Furthermore, the first control unit 21 includes: a first proportional unit 320, used to multiply the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit with a first proportional coefficient km1 to obtain a first current reference value Iref1, which is used as the current reference value of the current control loop of the single-phase PFC circuit 100.

[0096] The third calculation unit 330 is used to receive the first current reference value Iref1, the output current value IoAC of the AC terminal of the single-phase PFC circuit, and the inductor current IL flowing through the inductor, and output the first current indication signal Is1.

[0097] That is, the current reference value of the control loop of the single-phase PFC circuit 100 is determined based on the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit, so that the output current of the single-phase PFC circuit 100 can quickly follow the grid voltage connected to it, preventing energy from flowing back to the bus capacitor Cbulk, avoiding triggering overvoltage of the bus capacitor or damage to the switching transistor in the single-phase PFC circuit 100.

[0098] For further details, please refer to... Figure 7The schematic diagram of a single-phase on-board charger according to an embodiment of this application shows that the controller 20 further includes: an off-grid mode control unit 22, the off-grid mode control unit 22 including:

[0099] The first calculation unit 340 is used to receive the real-time AC voltage signal Vac and the AC voltage set value Vac_s at the AC terminal of the single-phase PFC circuit, and output the AC voltage difference Vs.

[0100] The first compensation unit 350 is used to obtain the second current reference value Iref2 based on the AC voltage difference Vs;

[0101] The second calculation unit 360 is used to receive the second current reference value Iref2, the output current value IoAC of the AC terminal of the single-phase PFC circuit, and the inductor current IL flowing through the inductor, and output the second current indication signal Is2.

[0102] Selection unit 370 is used to receive the first current indication signal Is1 and the second current indication signal Is2. When the bus voltage Vbulk on the bus capacitor Cbulk of the single-phase PFC circuit 100 is greater than the bus voltage setting value Vbulk_set and the duration is greater than the first setting value, selection unit 370 outputs the first current indication signal Is1 to control signal generation unit 390; when the bus voltage Vbulk on the bus capacitor Cbulk of the single-phase PFC circuit 100 is less than the bus voltage setting value Vbulk_set, selection unit 370 outputs the second current indication signal Is2 to control the single-phase on-board charger to work in off-grid mode.

[0103] That is, when the single-phase on-board charger is working in off-grid mode, the voltage outer loop determines the current reference value of the current inner loop.

[0104] For further details, please refer to... Figure 8 The schematic diagram of a single-phase on-board charger according to an embodiment of this application shows that the controller 20 further includes a grid-connected mode control unit 23, which is used to receive a grid-connected indication signal SC and output a third current indication signal Is3 to the selection unit 370 according to the grid-connected indication signal SC. When the selection unit 370 receives the third current indication signal Is3, the selection unit 370 outputs the third current indication signal Is3 to the control signal generation unit 390. The switch control signal generated by the control signal generation unit 390 causes the single-phase on-board charger to work in grid-connected mode.

[0105] In other words, when a grid connection command is received, the single-phase on-board charger can be controlled to operate in grid connection mode. It can achieve switching between grid connection and off-grid modes, and can avoid overvoltage triggering of the bus capacitor Cbulk, or damage to the switching transistor in the single-phase PFC circuit 100, thus achieving rapid grid connection and off-grid switching without error reports or shutdown.

[0106] For further details, please refer to... Figure 4 The grid-connected mode control unit 23 includes an inverter grid-connected mode control unit 231, comprising:

[0107] The second proportional unit 381 is used to receive the inverter grid connection command signal Icmd from the whole vehicle and output the current indication signal Isc.

[0108] Phase-locked unit 383 is used to receive the real-time AC voltage signal Vac at the AC terminal of the single-phase PFC circuit and output the phase-locked indication signal θ.

[0109] The fourth calculation unit 382 is used to receive the current indication signal Isc and the phase-locked signal θ, and output the third current reference value Iref3;

[0110] The fifth calculation unit 384 is used to receive the third current reference value Iref3, the output current value IoAC of the AC terminal of the single-phase PFC circuit, and the inductor current IL flowing through the inductor, and output the third current indication signal Is31.

[0111] When the selection unit 370 receives the third current indication signal Is31, the selection unit 370 outputs the third current indication signal Is31 to the control signal generation unit 390. The switch control signal generated by the control signal generation unit 390 causes the single-phase on-board charger to operate in inverter grid-connected mode.

[0112] At this time, the switch control signal controls the single-phase PFC circuit 100 to invert the DC power on the bus capacitor Cbulk into AC power that is connected to the power grid.

[0113] For further details, please refer to... Figure 4 The grid-connected mode control unit 23 includes a charging mode control unit 232, comprising:

[0114] The sixth calculation unit 385 is used to receive the bus voltage feedback signal Vbulk_f of the bus capacitor Cbulk of the single-phase PFC circuit and the bus voltage setting value Vbulk_set, and output the bus voltage difference Vbc.

[0115] The second compensation unit 386 is used to receive the bus voltage difference Vbc and output the fourth current reference value Iref4.

[0116] The seventh calculation unit 387 is used to receive the fourth current reference value Iref4 and the inductor current IL flowing through the inductor, and output the third current indication signal Is32.

[0117] When the selection unit 370 receives the third current indication signal Is32, the selection unit 370 outputs the third current indication signal Is32 to the control signal generation unit 390, and the switch control signal generated by the control signal generation unit 390 causes the single-phase on-board charger to work in charging mode.

[0118] At this time, the switch control signal controls the single-phase PFC circuit 100 to convert the AC power from the grid into DC power on the bus capacitor Cbulk.

[0119] Specifically, during the process of the off-grid mode control unit 22 controlling the single-phase on-board charger to operate in off-grid mode, the judgment unit 310 determines whether the bus voltage Vbulk on the bus capacitor Cbulk is greater than the bus voltage set value Vbulk_s. If so, and the duration is greater than the first set value, the first control unit 21 controls the bus capacitor Cbulk of the single-phase PFC circuit to release electrical energy; otherwise, the off-grid mode control unit 22 controls the single-phase on-board charger to continue operating in off-grid mode.

[0120] During the process of the bus capacitor of the single-phase PFC circuit releasing electrical energy, if a grid connection indication signal SC is received, the single-phase on-board charger is made to work in grid connection mode. If not, it is determined whether the duration is greater than a second set value. If yes, the power is turned off. If no, the first control unit 21 controls the bus capacitor of the single-phase PFC circuit to release electrical energy.

[0121] That is, the single-phase on-board charger is controlled to operate in the corresponding grid-connected mode according to the received actual grid-connected mode operation command. When an inverter grid-connected mode operation command is received, the single-phase on-board charger is controlled to operate in inverter grid-connected mode; when a charging mode operation command is received, the single-phase on-board charger is controlled to operate in charging mode.

[0122] Thus, this application can accommodate both off-grid to inverter-grid and off-grid to charging-grid switching modes, covering all working modes of single-phase on-board chargers.

[0123] For further details, please refer to... Figure 1 as well as Figures 4 to 8The single-phase on-board charger also includes a bidirectional DC / DC converter 200, the first DC terminal of which is connected to the DC terminal of the single-phase PFC circuit 100, and the second DC terminal of which is connected to the high-voltage battery unit HV.

[0124] This application also provides an electric vehicle, including the single-phase on-board charger described above.

[0125] The structure, principle, and advantages of single-phase on-board chargers are the same as those described above, and will not be repeated here.

[0126] In one specific embodiment, the first proportional unit 320 has a first proportional coefficient km1, and the second proportional unit 381 has a second proportional coefficient km2. In practical applications, the first proportional coefficient km1 and the second proportional coefficient km2 can be determined based on the actual circuit parameters of the single-phase on-board charger.

[0127] The aforementioned controller 20 is a digital controller, such as a DSP or MCU. Therefore, the proportional unit, calculation unit, and compensation unit are all implemented through software programming. This application only changes the software control strategy, without requiring modification to the hardware circuit, resulting in low cost.

[0128] In one specific embodiment, the first calculation unit 340 described above is used to perform a subtraction operation between the AC voltage setting value Vac_s and the real-time AC voltage signal Vac.

[0129] In one specific embodiment, the second calculation unit 360 is used to subtract the difference between the output current value IoAC of the single-phase PFC circuit and the inductor current IL flowing through the inductor, and then perform a subtraction operation with the second current reference value Iref2.

[0130] In one specific embodiment, the third calculation unit 330 described above is used to subtract the difference between the output current value IoAC of the single-phase PFC circuit and the inductor current IL flowing through the inductor, and then perform a subtraction operation with the first current reference value Iref1.

[0131] In one specific embodiment, the fourth calculation unit 382 described above is used to perform a multiplication operation between the current indication signal Isc and the phase-locked signal θ.

[0132] In one specific embodiment, the fifth calculation unit 384 described above is used to subtract the difference between the output current value IoAC of the single-phase PFC circuit and the inductor current IL flowing through the inductor, and then perform a subtraction operation with the third current reference value Iref3.

[0133] In one specific embodiment, the sixth calculation unit 385 described above is used to perform a subtraction operation between the bus voltage setting value Vbulk_set and the bus voltage feedback signal Vbulk_f.

[0134] In one specific embodiment, the seventh calculation unit 387 described above performs a subtraction operation between the fourth current reference value Iref4 and the inductor current IL flowing through the inductor.

[0135] In one specific embodiment, the compensation unit described above is a proportional, integral, or differential unit, or a proportional-integral or proportional-differential unit, or a proportional-integral-differential unit, and this application does not limit it in this way.

[0136] Although embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

[0137] Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, apparatuses, methods, and steps described in the specification. As will be readily understood by those skilled in the art from the disclosure of this publication, processes, machines, manufactures, compositions of matter, means, methods, or steps that perform substantially the same function, currently exist or will be developed or implemented thereafter, will yield substantially the same results as the corresponding embodiments described herein that are available according to this disclosure. Therefore, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, apparatuses, methods, or steps within their scope.

Claims

1. A control method for a single-phase on-board charger, wherein the single-phase on-board charger includes a single-phase PFC circuit, said single-phase PFC circuit being a bidirectional PFC circuit, characterized in that, include: S10: The controller controls the single-phase on-board charger to operate in off-grid mode; S20: Determine whether the bus voltage of the bus capacitor of the single-phase PFC circuit is greater than the bus voltage setting value. If yes, proceed to step S40; otherwise, proceed to step S10. S40: Determine whether the duration is greater than the first set value. If yes, proceed to step S50; otherwise, proceed to step S10. S50: Based on the real-time AC voltage signal at the AC terminal of the single-phase PFC circuit, determine the current reference value of the current control loop of the single-phase PFC circuit, so that the switching control signal output by the controller controls the bus capacitor of the single-phase PFC circuit to release electrical energy. S60: Determine whether a grid-connected mode working command has been received. If yes, proceed to step S80; otherwise, proceed to step S70. S80: The controller controls the single-phase on-board charger to operate in grid-connected mode; S70: Determine if the duration exceeds the second preset value. If yes, proceed to the shutdown step S90; otherwise, proceed to step S50. In step S50, the first proportional unit in the controller multiplies the real-time AC voltage signal at the AC terminal of the single-phase PFC circuit with the first proportional coefficient to obtain a first current reference value, which is used as the current reference value of the current control loop of the single-phase PFC circuit. The third calculation unit within the controller receives the first current reference value, the output current value of the AC terminal of the single-phase PFC circuit, and the inductance current flowing through the inductor of the AC terminal of the single-phase PFC circuit, and outputs the first current indication signal. The control signal generation unit in the controller outputs a switch control signal according to the first current indication signal, so that the bus capacitor of the single-phase PFC circuit releases electrical energy.

2. The single-phase on-board charger control method according to claim 1, characterized in that, In step S10, the first calculation unit in the controller receives the real-time AC voltage signal and the AC voltage set value of the AC terminal of the single-phase PFC circuit, and outputs the AC voltage difference. The first compensation unit within the controller obtains a second current reference value based on the AC voltage difference; The second calculation unit within the controller receives the second current reference value, the output current value of the AC terminal of the single-phase PFC circuit, and the inductance current flowing through the inductor of the AC terminal of the single-phase PFC circuit, and outputs a second current indication signal. The control signal generation unit in the controller outputs a switch control signal according to the second current indication signal, so that the single-phase on-board charger works in off-grid mode.

3. The single-phase on-board charger control method according to claim 2, characterized in that, Step S60 includes: Step S61: Determine whether an inverter grid-connected mode operating command has been received, and Step S62: Determine whether a charging mode operating command has been received; Step S80 includes: Step S81: The controller controls the single-phase on-board charger to operate in inverter grid-connected mode, and Step S82: The controller controls the single-phase on-board charger to operate in charging mode. Specifically, after step S50, step S61 is executed. If the judgment result of step S61 is negative, step S62 is executed. If the judgment result of step S61 is positive, step S81 is executed. If the judgment result of step S62 is negative, step S70 is executed. If the judgment result of step S62 is positive, step S82 is executed.

4. The single-phase on-board charger control method according to claim 3, characterized in that, In step S81, the second proportional unit in the controller receives the inverter grid connection command signal from the whole vehicle and outputs a current indication signal; The phase-locked unit receives the real-time AC voltage signal from the AC terminal of the single-phase PFC circuit and outputs a phase-locked indication signal; The fourth calculation unit receives the current indication signal and the phase-locked loop indication signal, and outputs a third current reference value; The fifth calculation unit receives the third current reference value, the output current value of the AC terminal of the single-phase PFC circuit, and the inductance current of the inductor flowing through the AC terminal of the single-phase PFC circuit, and outputs the third current indication signal. The control signal generation unit in the controller outputs a switch control signal according to the third current indication signal, so that the single-phase on-board charger operates in inverter grid-connected mode.

5. The single-phase on-board charger control method according to claim 3, characterized in that, In step S82, the sixth calculation unit in the controller receives the bus voltage feedback signal of the bus capacitor of the single-phase PFC circuit and the bus voltage set value, and outputs the bus voltage difference. The second compensation unit receives the bus voltage difference and outputs a fourth current reference value. The seventh calculation unit receives the fourth current reference value and the inductor current flowing through the inductor at the AC terminal of the single-phase PFC circuit, and outputs the third current indication signal. The control signal generation unit in the controller outputs a switch control signal according to the third current indication signal, so that the single-phase on-board charger works in charging mode.

6. A single-phase on-board charger, characterized in that, include: A single-phase PFC circuit includes a switching transistor unit, which includes at least one switching transistor. An inductor is connected between the switching transistor unit and the AC terminal of the single-phase PFC circuit. The switching transistor unit is connected in parallel with a bus capacitor to form the DC terminal of the single-phase PFC circuit. The AC terminal of the single-phase PFC circuit is used to supply power to the load or connect to the power grid. The controller performs the single-phase on-board charger control method according to any one of claims 1-5.

7. The single-phase on-board charger according to claim 6, characterized in that, The controller includes a first control unit, the first control unit comprising: The first proportional unit is used to multiply the real-time AC voltage signal at the AC terminal of the single-phase PFC circuit with the first proportional coefficient to obtain a first current reference value, which is used as the current reference value of the current control loop of the single-phase PFC circuit. The third calculation unit is used to receive the first current reference value, the output current value of the AC terminal of the single-phase PFC circuit, and the inductor current flowing through the inductor, and output the first current indication signal.

8. The single-phase on-board charger according to claim 7, characterized in that, The controller also includes: Off-grid mode control unit, the off-grid mode control unit comprising: The first calculation unit is used to receive the real-time AC voltage signal and AC voltage set value of the AC terminal of the single-phase PFC circuit, and output the AC voltage difference. The first compensation unit is used to obtain a second current reference value based on the AC voltage difference; The second calculation unit is used to receive the second current reference value, the output current value of the AC terminal of the single-phase PFC circuit, and the inductor current flowing through the inductor, and output the second current indication signal. The selection unit is used to receive the first current indication signal and the second current indication signal. When the bus voltage on the bus capacitor of the single-phase PFC circuit is greater than the bus voltage setting value and the duration is greater than the first setting value, the selection unit outputs the first current indication signal to the control signal generation unit. When the bus voltage on the bus capacitor of the single-phase PFC circuit is less than the bus voltage setting value, the selection unit outputs the second current indication signal to the control signal generation unit to control the single-phase on-board charger to work in off-grid mode.

9. The single-phase on-board charger according to claim 8, characterized in that, The controller also includes a grid-connected mode control unit, which is used to receive a grid-connected indication signal and output a third current indication signal to the selection unit according to the grid-connected indication signal. When the selection unit receives the third current indication signal, the selection unit outputs the third current indication signal to the control signal generation unit. The switch control signal generated by the control signal generation unit causes the single-phase on-board charger to work in grid-connected mode.

10. The single-phase on-board charger according to claim 9, characterized in that, The grid-connected mode control unit includes an inverter grid-connected mode control unit, comprising: The second proportional unit is used to receive the inverter grid connection command signal from the whole vehicle and output a current indication signal; The phase-locked unit is used to receive the real-time AC voltage signal at the AC terminal of the single-phase PFC circuit and output a phase-locked indication signal. The fourth calculation unit is used to receive the current indication signal and the phase-locked signal, and output a third current reference value; The fifth calculation unit is used to receive the third current reference value, the output current value of the AC terminal of the single-phase PFC circuit, and the inductor current flowing through the inductor, and output the third current indication signal. When the selection unit receives the third current indication signal, the selection unit outputs the third current indication signal to the control signal generation unit. The switch control signal generated by the control signal generation unit causes the single-phase on-board charger to operate in inverter grid-connected mode.

11. The single-phase on-board charger according to claim 9, characterized in that, The grid-connected mode control unit includes a charging mode control unit, comprising: The sixth calculation unit is used to receive the bus voltage feedback signal of the bus capacitor of the single-phase PFC circuit and the bus voltage set value, and output the bus voltage difference. The second compensation unit is used to receive the bus voltage difference and output a fourth current reference value. The seventh calculation unit is used to receive the fourth current reference value and the inductor current flowing through the inductor, and output a third current indication signal. When the selection unit receives the third current indication signal, the selection unit outputs the third current indication signal to the control signal generation unit, and the switch control signal generated by the control signal generation unit causes the single-phase on-board charger to work in charging mode.

12. The single-phase on-board charger according to claim 6, characterized in that, It also includes a bidirectional DC / DC converter, the first DC terminal of which is connected to the DC terminal of the single-phase PFC circuit, and the second DC terminal of which is connected to the high-voltage battery unit.

13. The single-phase on-board charger according to claim 9, characterized in that, During the process of the off-grid mode control unit controlling the single-phase on-board charger to operate in off-grid mode, the judgment unit determines whether the bus voltage on the bus capacitor is greater than the bus voltage set value. If so, and the duration is greater than the first set value, the first control unit controls the bus capacitor of the single-phase PFC circuit to release electrical energy; otherwise, the off-grid mode control unit controls the single-phase on-board charger to continue operating in off-grid mode. During the process of the bus capacitor of the single-phase PFC circuit releasing electrical energy, if a grid connection indication signal is received, the single-phase on-board charger will operate in grid connection mode. If not, it will be determined whether the duration is greater than a second set value. If yes, the charger will be turned off. If no, the first control unit will control the bus capacitor of the single-phase PFC circuit to release electrical energy.

14. An electric vehicle, characterized in that, include: The single-phase on-board charger as described in claim 6.

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