Bidirectional circuit, vehicle-mounted charger and electric vehicle

Abstract

The embodiment of the utility model provides a bidirectional circuit, a vehicle-mounted charger and an electric vehicle. The bidirectional circuit comprises a transmitting circuit and a pull-down circuit, the transmitting circuit comprises a first semiconductor switch and a second semiconductor switch; and when the bidirectional circuit works in a discharge mode, the first semiconductor switch and the second semiconductor switch are in an alternate conduction state, so that the transmitting end of the transmitting circuit transmits CP signals. According to the embodiment of the invention, the cost and size of the bidirectional circuit can be reduced.

Description

Technical Field

[0001] This application relates to the technical field of electronic circuits, and particularly to a bidirectional circuit, an on-vehicle charger, and an electric vehicle. Background Art

[0002] At present, more and more on-vehicle chargers of electric vehicles have the bidirectional functions of charging and discharging. When an electric vehicle acts as a generator, it can provide alternating current that meets the requirements of the mains for users, and can also act as a charging pile to charge another electric vehicle. When the electric vehicle acts as a charging pile, the on-vehicle charger will interact with another electric vehicle as a charging pile role, and then the on-vehicle charger needs to provide a control pilot (CP) signal that meets the national standard requirements. At the same time, when the electric vehicle is used as a charger, it also needs to interact with the charging pile to provide a resistance value signal that meets the national standard. Currently, the charger needs to implement both the charger function and the charging pile function, so it needs to have both a CP sending circuit and a pull-down resistor circuit. However, these two circuits cannot be connected to the CP line at the same time. Therefore, it is necessary to design the switching between the two circuits. The commonly used switching method is to switch through a single-pole double-throw relay. The common end of the relay is connected to the CP line, and the other two contacts are respectively connected to the CP sending circuit and the pull-down resistor circuit, and the switching is carried out back and forth according to the required functions.

[0003] The above switching method through a relay has the following disadvantages: the relay has a large volume and occupies space, which is not conducive to the miniaturization and lightweight design of the product, and the cost of the relay is relatively high. Summary of the Utility Model

[0004] The embodiments of this application provide a bidirectional circuit, an on-vehicle charger, and an electric vehicle, which can reduce the cost and volume of the bidirectional circuit.

[0005] The first aspect of the embodiments of this application provides a bidirectional circuit, including a sending circuit and a pull-down circuit; the sending circuit includes a first semiconductor switch and a second semiconductor switch; the sending end of the sending circuit is connected to the receiving end of the pull-down circuit.

[0006] When the bidirectional circuit works in the discharging mode, the first semiconductor switch and the second semiconductor switch are in an alternating conduction state, so that the sending end of the sending circuit sends a CP signal.

[0007] Optionally, the sending circuit further includes a first diode and a second diode, and the body diode of the first semiconductor switch and the first diode form a first bidirectional cut-off circuit, and the body diode of the second semiconductor switch and the second diode form a second bidirectional cut-off circuit.

[0008] Optionally, the first end of the first semiconductor switch is connected to the positive power supply, the second end of the first semiconductor switch is connected to the positive electrode of the first diode, the negative electrode of the first diode is connected to the positive electrode of the second diode and the transmitting end of the transmitting circuit, the negative electrode of the second diode is connected to the first end of the second semiconductor switch, and the second end of the second semiconductor switch is connected to the negative power supply.

[0009] Optionally, the transmitting circuit further includes a third resistor and a fourth resistor. The first end of the first semiconductor switch is connected to the positive power supply, the second end of the first semiconductor switch is connected to the first end of the third resistor, the second end of the third resistor is connected to the positive electrode of the first diode, the negative electrode of the first diode is connected to the positive electrode of the second diode and the transmitting end of the transmitting circuit, the negative electrode of the second diode is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the second semiconductor switch, and the second end of the second semiconductor switch is connected to the negative power supply.

[0010] Optionally, the transmitting circuit further includes a voltage dividing circuit and a third semiconductor switch. The first end of the voltage dividing circuit is connected to the positive power supply, the second end of the voltage dividing circuit is connected to the first end of the third semiconductor switch, the second end of the third semiconductor switch is connected to the negative power supply, and the voltage dividing port of the voltage dividing circuit is connected to the control end of the first semiconductor switch.

[0011] Optionally, the voltage dividing circuit includes a fifth resistor and a sixth resistor. The first end of the fifth resistor is connected to the positive power supply, the second end of the fifth resistor is connected to the first end of the sixth resistor and the control end of the first semiconductor switch, and the second end of the sixth resistor is connected to the first end of the third semiconductor switch.

[0012] Optionally, the first semiconductor switch, the second semiconductor switch, and the third semiconductor switch are all field effect transistors.

[0013] Optionally, the pull-down circuit includes a first pull-down switch and a second pull-down switch; when the bidirectional circuit operates in the discharge mode, both the first pull-down switch and the second pull-down switch are in the off state, so that the pull-down circuit stops working.

[0014] Optionally, when the bidirectional circuit operates in the charging mode, at least one of the first pull-down switch and the second pull-down switch is in the on state, so that the receiving end of the pull-down circuit receives the control pilot CP signal; both the first semiconductor switch and the second semiconductor switch are in the off state, so that the transmitting circuit stops working.

[0015] Optionally, the pull-down circuit further includes a first resistor and a second resistor. The first end of the first resistor is connected to the first end of the second resistor. The second end of the first resistor is connected to the first end of the first pull-down switch. The second end of the first pull-down switch is connected to a negative power supply. The second end of the second resistor is connected to the first end of the second pull-down switch. The second end of the second pull-down switch is connected to the negative power supply.

[0016] Optionally, the bidirectional circuit further includes a third diode. The anode of the third diode is connected to the receiving end of the pull-down circuit. The cathode of the third diode is connected to the first end of the first resistor and the first end of the second resistor.

[0017] Optionally, both the first pull-down switch and the second pull-down switch are mechanical switches or semiconductor switches.

[0018] In a second aspect of the embodiments of the present application, a vehicle-mounted charger is provided, including the bidirectional circuit according to any one of the first aspects of the embodiments of the present application.

[0019] In a third aspect of the embodiments of the present application, an electric vehicle is provided, including the vehicle-mounted charger according to any one of the second aspects of the embodiments of the present application. The vehicle-mounted charger can charge the power battery.

[0020] The bidirectional circuit of the embodiments of the present application includes a sending circuit and a pull-down circuit; the sending circuit includes a first semiconductor switch and a second semiconductor switch; the sending end of the sending circuit is connected to the receiving end of the pull-down circuit; when the bidirectional circuit operates in the discharging mode, the first semiconductor switch and the second semiconductor switch are in an alternating conduction state, so that the sending end of the sending circuit sends a CP signal. In the embodiments of the present application, when the bidirectional circuit operates in the discharging mode, the first semiconductor switch and the second semiconductor switch are in an alternating conduction state, so that the sending end of the sending circuit sends a CP signal, and the bidirectional circuit can operate in the discharging mode. Compared with using a relay to switch, using semiconductor switches can also achieve operation in the discharging mode, thereby reducing the cost and volume of the bidirectional circuit. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 is a schematic structural diagram of a bidirectional circuit provided by an embodiment of the present application;

[0023] Figure 2It is a schematic structural diagram of another bi-directional circuit provided by an embodiment of the present application;

[0024] Figure 3 It is a schematic structural diagram of another bi-directional circuit provided by an embodiment of the present application;

[0025] Figure 4 It is a schematic structural diagram of another bi-directional circuit provided by an embodiment of the present application;

[0026] Figure 5 It is a schematic structural diagram of an on-vehicle charger provided by an embodiment of the present application;

[0027] Figure 6 It is a schematic structural diagram of an electric vehicle provided by an embodiment of the present application;

[0028] Figure 7 Schematic structural diagram of a charging system provided by an embodiment of the present application, which uses a relay to implement the switching between a charging mode and a discharging mode. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present application.

[0030] Terms such as "first" and "second" in the specification and claims of the present application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, a system, a product or a device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, products or devices.

[0031] Referring to "embodiment" in the present application means that a specific feature, structure or characteristic described in combination with the embodiment can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described in the present application can be combined with other embodiments.

[0032] Please refer to Figure 1 , Figure 1 It is a schematic structural diagram of a bi-directional circuit provided by an embodiment of the present application. As Figure 1As shown, the bidirectional circuit may include a transmission circuit and a pull-down circuit; the transmission circuit includes a first semiconductor switch Q1 and a second semiconductor switch Q2; the transmission end of the transmission circuit is connected to the receiving end of the pull-down circuit;

[0033] When the bidirectional circuit operates in the discharge mode, the first semiconductor switch Q1 and the second semiconductor switch Q2 are in an alternating conduction state, so that the transmission end of the transmission circuit transmits a CP signal.

[0034] In the embodiments of the present application, the semiconductor switch may include any one of a field effect transistor (FET), a bipolar junction transistor (BJT), and an insulated gate bipolar transistor (IGBT). The field effect transistor may include a metal-oxide-semiconductor field effect transistor (MOSFET), and the MOSFET may also be simply referred to as a MOS transistor. The MOS transistor may include an N-channel MOS transistor (abbreviated as NMOS) or a P-channel MOS transistor (abbreviated as PMOS).

[0035] Figure 1 In the example, the first semiconductor switch Q1 is a PMOS, and the second semiconductor switch Q2 is an NMOS. Optionally, both the first semiconductor switch Q1 and the second semiconductor switch Q2 may be PMOS or NMOS.

[0036] Compared with a relay, the semiconductor switch has the advantages of small volume, low price, and fast response speed.

[0037] The bidirectional circuit in the embodiments of the present application can operate in the discharge mode.

[0038] When the bidirectional circuit operates in the discharge mode, the pull-down circuit stops working, and the first semiconductor switch Q1 and the second semiconductor switch Q2 are in an alternating conduction state, so that the transmission end of the transmission circuit transmits a control pilot (CP) signal. When the bidirectional circuit operates in the discharge mode, the bidirectional circuit can send a CP signal to the outside through the transmission end of the transmission circuit. Exemplarily, when the bidirectional circuit operates in the discharge mode, the bidirectional circuit can send a CP signal to the receiver of the CP signal (for example, the on-vehicle charger of other vehicles) through the transmission end of the transmission circuit, so that the bidirectional circuit charges other vehicles. At this time, the bidirectional circuit is the sender of the CP signal.

[0039] The CP signal is a pulse signal with a frequency of one thousand hertz (1K Hz), a duty cycle of 5% - 95%, and an amplitude of ±12V. When the charging pile charges the power battery of the electric vehicle through the on-vehicle charger, the charging pile is responsible for outputting the CP signal, and the on-vehicle charger is responsible for changing the amplitude of the CP signal in the way of series resistance. The charging pile then conducts alternating current transmission by detecting the change of the CP amplitude, so as to achieve the interaction function. The CP signal can be a pulse width modulation (PWM) signal.

[0040] In the embodiment of the present application, when the bidirectional circuit works in the discharge mode, the first semiconductor switch Q1 and the second semiconductor switch Q2 are in an alternating conduction state, so that the sending end of the sending circuit sends the CP signal, and the bidirectional circuit can work in the discharge mode. Compared with using a relay to switch, using semiconductor switches can also achieve working in the discharge mode, thereby reducing the cost and volume of the bidirectional circuit.

[0041] Optionally, as Figure 1 shown, the sending circuit further includes a first diode D1 and a second diode D2. The first end of the first semiconductor switch Q1 is connected to the positive power supply, the second end of the first semiconductor switch Q1 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the anode of the second diode D2 and the sending end of the sending circuit, the cathode of the second diode D2 is connected to the first end of the second semiconductor switch Q2, and the second end of the second semiconductor switch Q2 is connected to the negative power supply.

[0042] The voltage provided by the positive power supply and the voltage provided by the negative power supply have the same amplitude and opposite polarities. As Figure 1 shown, the positive power supply can be a +12V DC power supply, which can provide the amplitude of the positive pulse of the CP signal. The negative power supply can be a -12V DC power supply, which can provide the amplitude of the negative pulse of the CP signal.

[0043] When the sending circuit sends the CP signal, the first semiconductor switch Q1 and the second semiconductor switch Q2 can conduct alternately, so as to realize the output of the CP signal. Exemplarily, when the first semiconductor switch Q1 conducts and the second semiconductor switch Q2 turns off, the CP signal sent by the sending circuit is a positive pulse (+12V), and when the first semiconductor switch Q1 turns off and the second semiconductor switch Q2 conducts, the CP signal sent by the sending circuit is a negative pulse (-12V).

[0044] Optionally, the body diode of the first semiconductor switch Q1 and the first diode D1 form a first bidirectional cut-off circuit, and the body diode of the second semiconductor switch Q2 and the second diode D2 form a second bidirectional cut-off circuit.

[0045] In the charging mode, the body diode of the first semiconductor switch Q1 and the first diode D1 form a first bidirectional cut-off circuit, and the body diode of the second semiconductor switch Q2 and the second diode D2 form a second bidirectional cut-off circuit. The CP signal received by the receiving end of the pull-down circuit will not be affected by the transmitting circuit, thus ensuring the reliability of the received CP signal.

[0046] Please refer to Figure 2 , Figure 2 which is a schematic structural diagram of another bidirectional circuit provided by an embodiment of the present application. As Figure 2 shown, the pull-down circuit includes a first pull-down switch S1 and a second pull-down switch S2. When the bidirectional circuit operates in the discharge mode, both the first pull-down switch S1 and the second pull-down switch S2 are in the off state, so that the pull-down circuit stops working.

[0047] In the embodiment of the present application, when the bidirectional circuit operates in the discharge mode, both the first pull-down switch S1 and the second pull-down switch S2 are in the off state, and the pull-down circuit cannot perform the pull-down function, and the pull-down circuit stops working. Thus, it is ensured that the CP signal sent by the bidirectional circuit to the outside through the sending end of the sending circuit will not pass through the pull-down circuit. The bidirectional circuit can send a CP signal to the receiving party of the CP signal (for example, the on-vehicle charger of other vehicles) through the sending end of the sending circuit, so that the bidirectional circuit charges other vehicles.

[0048] Optionally, when the bidirectional circuit operates in the charging mode, at least one of the first pull-down switch S1 and the second pull-down switch S2 is in the on state, so that the receiving end of the pull-down circuit receives the control pilot (CP) signal; both the first semiconductor switch Q1 and the second semiconductor switch Q2 are in the off state, so that the sending circuit stops working.

[0049] The bidirectional circuit of the embodiment of the present application can operate in the charging mode or the discharge mode.

[0050] When the bidirectional circuit operates in the charging mode, both the first semiconductor switch Q1 and the second semiconductor switch Q2 are in the off state, and the sending circuit stops working. At least one of the first pull-down switch S1 and the second pull-down switch S2 is in the on state, so that the receiving end of the pull-down circuit can receive the control pilot (CP) signal. When the bidirectional circuit operates in the charging mode, the bidirectional circuit can receive the CP signal sent by the sending party of the CP signal (for example, an external charging pile or the on-vehicle charger of other vehicles) through the receiving end of the pull-down circuit. At this time, the bidirectional circuit is the receiving party of the CP signal.

[0051] When the bidirectional circuit operates in the discharging mode, the first pull-down switch S1 and the second pull-down switch S2 are both in the off state, the pull-down circuit stops working, and the first semiconductor switch Q1 and the second semiconductor switch Q2 are in an alternating conduction state, so that the transmitting end of the transmitting circuit transmits the CP signal. When the bidirectional circuit operates in the discharging mode, the bidirectional circuit can transmit the CP signal to the outside through the transmitting end of the transmitting circuit. Exemplarily, when the bidirectional circuit operates in the discharging mode, the bidirectional circuit can transmit the CP signal to the receiver of the CP signal (for example, the on-vehicle charger of other vehicles) through the transmitting end of the transmitting circuit, so that the bidirectional circuit charges other vehicles. At this time, the bidirectional circuit is the transmitter of the CP signal.

[0052] In the embodiment of the present application, by switching the states of the first semiconductor switch Q1, the second semiconductor switch Q2, the first pull-down switch S1, and the second pull-down switch S2, the bidirectional circuit can operate in the charging mode or the discharging mode. Compared with using a relay for switching, using semiconductor switches can also achieve the switching between the charging mode and the discharging mode, thereby reducing the cost and volume of the bidirectional circuit.

[0053] Optionally, as Figure 2 shown, the pull-down circuit further includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the first end of the second resistor R2. The second end of the first resistor R1 is connected to the first end of the first pull-down switch S1. The second end of the first pull-down switch S1 is connected to the negative power supply. The second end of the second resistor R2 is connected to the first end of the second pull-down switch S2. The second end of the second pull-down switch S2 is connected to the negative power supply.

[0054] Among them, the first resistor R1 and the second resistor R2 are pull-down resistors. When the bidirectional circuit operates in the charging mode, at least one of the first pull-down switch S1 and the second pull-down switch S2 is in the on state. At this time, it can be judged whether the amplitude of the CP signal meets the range specified by the national standard, so as to complete the state interaction between the transmitter of the CP signal and the receiver of the CP signal. Exemplarily, by successively closing the first pull-down switch S1 and the second pull-down switch S2, the amplitude of the CP signal can be judged, so as to determine the working state.

[0055] Among them, when the bidirectional circuit operates in the charging mode, the first semiconductor switch Q1 and the second semiconductor switch Q2 are both in the off state (i.e., the turned-off state), and Q1 is also in the off state at the same time. The body diode of the first semiconductor switch Q1 and the first diode D1 form a first bidirectional cut-off circuit, which is in the bidirectional cut-off state and can block the positive power supply (for example, a +12V power supply) from the CP signal. At the same time, the body diode of the second semiconductor switch Q2 and the second diode D2 form a second bidirectional cut-off circuit, which can block the negative power supply (for example, a -12V power supply) from the CP signal, so as to achieve the purpose of not affecting the amplitude of the CP signal.

[0056] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of another bidirectional circuit provided by an embodiment of the present application. As Figure 3 shown, on the basis of Figure 2 , the sending circuit of Figure 3 further includes a third resistor R3 and a fourth resistor R4. The first end of the first semiconductor switch Q1 is connected to the positive power supply, the second end of the first semiconductor switch Q1 is connected to the first end of the third resistor R3, the second end of the third resistor R3 is connected to the positive electrode of the first diode D1, the negative electrode of the first diode D1 is connected to the positive electrode of the second diode D2 and the sending end of the sending circuit, the negative electrode of the second diode D2 is connected to the first end of the fourth resistor R4, the second end of the fourth resistor R4 is connected to the first end of the second semiconductor switch Q2, and the second end of the second semiconductor switch Q2 is connected to the negative power supply.

[0057] Among them, the third resistor R3 and the fourth resistor R4 are current-limiting resistors. The third resistor R3 can limit the current flowing through the first semiconductor switch Q1, and can avoid the current flowing through the first semiconductor switch Q1 from being too large when the first semiconductor switch Q1 is turned on, thereby playing a role in protecting the first semiconductor switch Q1. The fourth resistor R4 can limit the current flowing through the second semiconductor switch Q2, and can avoid the current flowing through the second semiconductor switch Q2 from being too large when the second semiconductor switch Q2 is turned on, thereby playing a role in protecting the second semiconductor switch Q2.

[0058] Optionally, as Figure 3 shown, the bidirectional circuit further includes a third diode D3. The positive electrode of the third diode D3 is connected to the receiving end of the pull-down circuit, and the negative electrode of the third diode D3 is connected to the first end of the first resistor R1 and the first end of the second resistor R2.

[0059] When the bidirectional circuit operates in the charging mode, the third diode D3 can limit the amplitude of the CP signal, ensuring that the amplitude of the received CP signal is within the normal range, and accurately determining whether the amplitude of the CP signal meets the range specified by the national standard, thereby completing the state interaction between the sender and the receiver of the CP signal.

[0060] Please refer to Figure 4 , Figure 4 which is a schematic structural diagram of another bidirectional circuit provided by an embodiment of the present application. As Figure 4 shown, on the basis of Figure 3 , the sending circuit of Figure 4 further includes a voltage dividing circuit and a third semiconductor switch Q3. The first end of the voltage dividing circuit is connected to the positive power supply, the second end of the voltage dividing circuit is connected to the first end of the third semiconductor switch Q3, the second end of the third semiconductor switch Q3 is connected to the negative power supply, and the voltage dividing port of the voltage dividing circuit is connected to the control end of the first semiconductor switch Q1.

[0061] When the bidirectional circuit operates in the charging mode, at least one of the first pull - down switch S1 and the second pull - down switch S2 is in the on state, so that the receiving end of the pull - down circuit receives the control - guiding CP signal; the first semiconductor switch Q1, the second semiconductor switch Q2, and the third semiconductor switch Q3 are all in the off state, so that the sending circuit stops working;

[0062] When the bidirectional circuit operates in the discharging mode, the first semiconductor switch Q1 and the second semiconductor switch Q2 are in an alternating on state, so that the sending end of the sending circuit sends the CP signal; the first pull - down switch S1 and the second pull - down switch S2 are both in the off state, so that the pull - down circuit stops working.

[0063] Among them, when the third semiconductor switch Q3 is in the on state, the first semiconductor switch Q1 is on. When the third semiconductor switch Q3 is in the off state, the first semiconductor switch Q1 is off.

[0064] In the embodiments of the present application, an example is given where the first semiconductor switch Q1 is a PMOS, and the second semiconductor switch Q2 and the third semiconductor switch Q3 are both NMOS. By using three semiconductor switches (the first semiconductor switch Q1, the second semiconductor switch Q2, and the third semiconductor switch Q3), compared with using two semiconductor switches (the first semiconductor switch Q1 and the second semiconductor switch Q2), the voltage divided and applied to the control terminal of the first semiconductor switch Q1 can be controlled by adjusting the resistance value of the voltage division circuit, so as to accurately control the conduction or cutoff of the first semiconductor switch Q1. A control source can be used to output VIL and VIH to control the second semiconductor switch Q2 and the third semiconductor switch Q3 respectively. When the first semiconductor switch Q1 and the second semiconductor switch Q2 are not of the same type of semiconductor switch (one is a PMOS and the other is an NMOS), a control source can also accurately control the transmission circuit to output the CP signal, thereby reducing the control cost and expanding the application scenarios of the transmission circuit.

[0065] Optionally, the voltage division circuit includes a fifth resistor R5 and a sixth resistor R6. The first end of the fifth resistor R5 is connected to the positive power supply, the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6 and the control terminal of the first semiconductor switch Q1, and the second end of the sixth resistor R6 is connected to the first end of the third semiconductor switch Q3.

[0066] Optionally, the first semiconductor switch Q1, the second semiconductor switch Q2, and the third semiconductor switch Q3 are all field effect transistors. Exemplarily, the first semiconductor switch Q1 is a PMOS, and the second semiconductor switch Q2 and the third semiconductor switch Q3 are both NMOS.

[0067] Optionally, the first pull-down switch S1 and the second pull-down switch S2 are both mechanical switches or semiconductor switches. The mechanical switch may include a relay. The semiconductor switch may include any one of a field effect transistor, a bipolar junction transistor, and an insulated gate transistor. Exemplarily, the first pull-down switch S1 and the second pull-down switch S2 are both NMOS.

[0068] Please refer to Figure 5 , Figure 5 which is a schematic structural diagram of an on-vehicle charger provided by the embodiments of the present application. As Figure 5 shown, the on-vehicle charger includes a bidirectional circuit.

[0069] Please refer to Figure 6 , Figure 6 which is a schematic structural diagram of an electric vehicle provided by the embodiments of the present application. As Figure 6 shown, the electric vehicle includes an on-vehicle charger, and the on-vehicle charger can charge the power battery.

[0070] Figure 6 Taking electric vehicle 1 and electric vehicle 2 as examples for illustration. The on-vehicle charger 1 in electric vehicle 1 is in the charging mode, and the on-vehicle charger 2 in electric vehicle 2 is in the discharging mode. The bidirectional circuit in the on-vehicle charger 1 includes a transmitting circuit 1 and a pull-down circuit 1, and the bidirectional circuit 2 in the on-vehicle charger 2 includes a transmitting circuit 2 and a pull-down circuit 2. Among them, the transmitting end of the transmitting circuit 1 is connected to the receiving end of the pull-down circuit 1, the transmitting end of the transmitting circuit 2, and the receiving end of the pull-down circuit 2.

[0071] Taking Figure 6 as an example, the working principle of the bidirectional circuit is described. Figure 6 It is a vehicle-to-vehicle (VTOV) charging scenario. The control end of the second semiconductor switch Q2 is connected to the second signal VIL, and the control end of the third semiconductor switch Q3 is connected to the first signal VIH.

[0072] When the on-vehicle charger 1 in electric vehicle 1 is in the charging mode, the controller of the on-vehicle charger 1 outputs the first signal VIH as a low level. At this time, the third semiconductor switch Q3 in the transmitting circuit 1 is in the off state, and the first semiconductor switch Q1 in the transmitting circuit 1 is also in the off state. The body diode of the first semiconductor switch Q1 in the transmitting circuit 1 and the first diode D1 in the transmitting circuit 1 form a first bidirectional cut-off circuit to block +12V and the CP signal. At the same time, the controller of the on-vehicle charger 1 outputs the first signal VIL as a low level, then the second semiconductor switch Q2 in the transmitting circuit 1 is in the off state. The body diode of the second semiconductor switch Q2 in the transmitting circuit 1 and the second diode D2 in the transmitting circuit 1 form a second bidirectional cut-off circuit to block -12V and the CP signal, so as to achieve the purpose of not affecting the amplitude of the CP signal.

[0073] When the on-vehicle charger 1 in electric vehicle 1 is in the charging mode, the first pull-down switch S1 and the second pull-down switch S2 in the pull-down circuit 1 need to be closed successively to make the CP amplitude meet the range specified by the national standard and complete the state interaction.

[0074] When the on-board charger 2 in the electric vehicle 2 is in the discharge mode, the first pull-down switch S1 and the second pull-down switch S2 in the pull-down circuit 2 are both disconnected, and the pull-down circuit 2 will not cause the CP amplitude to change; at the same time, the controller of the on-board charger 2 outputs the first signal VIH and the second signal VIL as complementary square wave signals. When the first signal VIH is at a high level and the second signal VIL is at a low level, the third semiconductor switch Q3 in the sending circuit 2 is in an on state, and the second semiconductor switch Q2 in the sending circuit 2 is in an off state. The positive power supply generates a voltage divider on the fifth resistor R5 to drive the first semiconductor switch Q1 in the sending circuit 2 to be in an on state, and the sending circuit 2 outputs a high level of +12V. When the first signal VIH is at a low level and the second signal VIL is at a high level, the third semiconductor switch Q3 is in an off state, and the second semiconductor switch Q2 is in an on state, and the sending circuit 2 outputs a low level of -12V, thereby realizing the charging pile sending CP function through the on-board charger 2 in the electric vehicle 2. Exemplarily, R3=R4=1 kΩ, which is the resistance value defined by the national standard.

[0075] See also Figure 7 , Figure 7 The present application provides a schematic diagram of a charging system that uses a relay to switch between a charging mode and a discharging mode. Figure 7 As shown, the charging system includes: a CP sending circuit of a charging pile, a CP sending circuit of an on-board charger, a relay K1, and a pull-down circuit of an on-board charger. Among them, the relay K1 is a single-pole double-throw relay, the common terminal of the relay K1 is connected to the CP signal sent by the CP sending circuit of the charging pile, and the normally closed contact of the relay K1 is connected to the pull-down circuit of the on-board charger, wherein the sending circuit of the on-board charger is consistent with the principle of the CP sending circuit of the charging pile. When entering the charging mode, the contact of the relay K1 remains in a normally closed state, and the pull-down switches in the pull-down circuit of the on-board charger are controlled by the controller of the on-board charger to be turned on successively, completing the signal interaction, entering the charging process, and realizing the charging function. When entering the discharge mode, the pull-down switches in the pull-down circuit of the on-board charger are all disconnected by the controller of the on-board charger, and the contacts of the relay K1 are switched from normally closed contacts to normally open contacts. At this time, the CP sending circuit of the on-board charger outputs the CP signal to the outside, realizing the charging pile function of the on-board charger.

[0076] Figure 7 Relay K1 is used for switching. Since the relay is large in size and occupies space, it is not conducive to the miniaturization and lightweight design of the product, and the cost of the relay is relatively high.

[0077] Figure 6By switching the states of the first semiconductor switch Q1, the second semiconductor switch Q2, the first pull-down switch S1, and the second pull-down switch S2, the on-vehicle charger can operate in a charging mode or a discharging mode. Compared with Figure 7 using a relay switch, using semiconductor switches can also achieve the switching between the charging mode and the discharging mode, thereby reducing the cost and volume of the on-vehicle charger.

[0078] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0079] In several embodiments provided in the present application, it should be understood that the disclosed bidirectional circuit and on-vehicle charger can be implemented in other ways. For example, the bidirectional circuit embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

Claims

1. A bidirectional circuit, characterized in that: It includes a sending circuit and a pull-down circuit; the sending circuit includes a first semiconductor switch and a second semiconductor switch; the sending end of the sending circuit is connected to the receiving end of the pull-down circuit; When the bidirectional circuit operates in the discharge mode, the first semiconductor switch and the second semiconductor switch are in an alternate conduction state, so that the transmitting end of the transmitting circuit transmits a CP signal.

2. The bidirectional circuit according to claim 1, characterized in that: The transmitting circuit further includes a first diode and a second diode. The body diode of the first semiconductor switch and the first diode form a first bidirectional cutoff circuit. The body diode of the second semiconductor switch and the second diode form a second bidirectional cutoff circuit.

3. The bidirectional circuit according to claim 2, characterized in that: The first end of the first semiconductor switch is connected to a positive power supply, the second end of the first semiconductor switch is connected to the anode of the first diode, the cathode of the first diode is connected to the anode of the second diode and the transmitting end of the transmitting circuit, the cathode of the second diode is connected to the first end of the second semiconductor switch, and the second end of the second semiconductor switch is connected to a negative power supply.

4. The bidirectional circuit according to claim 2, characterized in that: The transmitting circuit also includes a third resistor and a fourth resistor, the first end of the first semiconductor switch is connected to a positive power supply, the second end of the first semiconductor switch is connected to the first end of the third resistor, the second end of the third resistor is connected to the anode of the first diode, the cathode of the first diode is connected to the anode of the second diode and the transmitting end of the transmitting circuit, the cathode of the second diode is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the second semiconductor switch, and the second end of the second semiconductor switch is connected to the negative power supply.

5. The bidirectional circuit according to claim 4, characterized in that: The transmitting circuit also includes a voltage divider circuit and a third semiconductor switch, wherein a first end of the voltage divider circuit is connected to the positive power supply, a second end of the voltage divider circuit is connected to a first end of the third semiconductor switch, a second end of the third semiconductor switch is connected to the negative power supply, and a voltage divider port of the voltage divider circuit is connected to a control end of the first semiconductor switch.

6. The bidirectional circuit according to claim 5, characterized in that: The voltage divider circuit includes a fifth resistor and a sixth resistor, the first end of the fifth resistor is connected to the positive power supply, the second end of the fifth resistor is connected to the first end of the sixth resistor and the control end of the first semiconductor switch, and the second end of the sixth resistor is connected to the first end of the third semiconductor switch.

7. The bidirectional circuit according to claim 5, characterized in that: The first semiconductor switch, the second semiconductor switch and the third semiconductor switch are all field effect transistors.

8. The bidirectional circuit according to any one of claims 1 to 7, characterized in that: The pull-down circuit includes a first pull-down switch and a second pull-down switch. When the bidirectional circuit operates in a discharge mode, the first pull-down switch and the second pull-down switch are both in an off state, so that the pull-down circuit stops operating.

9. The bidirectional circuit according to claim 8, characterized in that: When the bidirectional circuit operates in a charging mode, at least one of the first pull-down switch and the second pull-down switch is in an on state so that the receiving end of the pull-down circuit receives a control guide CP signal; and the first semiconductor switch and the second semiconductor switch are both in an off state so that the sending circuit stops working.

10. The bidirectional circuit according to claim 9, characterized in that: The pull-down circuit also includes a first resistor and a second resistor, wherein the first end of the first resistor is connected to the first end of the second resistor, the second end of the first resistor is connected to the first end of the first pull-down switch, the second end of the first pull-down switch is connected to a negative power supply, the second end of the second resistor is connected to the first end of the second pull-down switch, and the second end of the second pull-down switch is connected to the negative power supply.

11. The bidirectional circuit according to claim 10, characterized in that: The bidirectional circuit further includes a third diode, an anode of the third diode is connected to the receiving end of the pull-down circuit, and a cathode of the third diode is connected to the first end of the first resistor and the first end of the second resistor.

12. The bidirectional circuit according to any one of claims 9 to 11, characterized in that: The first pull-down switch and the second pull-down switch are both mechanical switches or semiconductor switches.

13. A vehicle-mounted charger, characterized in that: It comprises the bidirectional circuit as claimed in any one of claims 1 to 12.

14. An electric vehicle, characterized in that: It includes the on-board charger as claimed in claim 13.

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