Bidirectional On-Board Control Circuit with Charging and Discharging Functions and its Control Method

Abstract

This invention discloses a bidirectional on-board computer (OBC) control circuit and its control method with charging and discharging functions. It includes a switch module connecting the external electrical grid and the internal electrical grid, and a bidirectional OBC with charging mode, inverter mode, and AC / AC mode. In the charging mode, the external electrical grid charges the bidirectional OBC through the switch module. In the inverter mode, the bidirectional OBC discharges to the external electrical grid and / or the internal electrical grid through the switch module. In the AC / AC mode, the external electrical grid connects to the internal electrical grid through the switch module. This invention features soft start and soft start protection. When the OBC is in the internal discharge mode, the relay connected to the external L-line is disconnected, completely disconnecting the vehicle charging port from the circuit. This ensures that no electric shock will occur when a person comes into contact with the charging port, improving safety. The number of relays and the rated capacity are reduced, effectively reducing size and cost.

Description

Technical Field

[0001] This invention relates to vehicle power supply circuits, and more particularly to a bidirectional vehicle OBC control circuit with charging and discharging functions and its control method. Background Technology

[0002] With the increasing demand for bidirectional OBCs with in-vehicle discharge capabilities, current applications of bidirectional OBCs achieve charging or discharging functions by controlling the opening and closing of relays and using Hall effect sensors to detect the circuit current. When the bidirectional OBC is in charging mode, AC power is supplied to the OBC through the charging port to charge the battery; when the OBC is in inverter mode, the vehicle battery outputs voltage to the vehicle's charging port or in-vehicle interface through a discharge device to power related loads. Existing technology uses relays to control OBC charging or discharging, but this suffers from the drawback of requiring a large number of relays with high rated capacity.

[0003] Therefore, how to design a bidirectional vehicle OBC control circuit with charging and discharging functions, which has a small number of relays and a relatively small rated capacity, is a technical problem that the industry urgently needs to solve. Summary of the Invention

[0004] To address the aforementioned deficiencies in the existing technology, this invention proposes a bidirectional on-board OBC control circuit with charging and discharging functions and its control method.

[0005] The technical solution adopted in this invention is to design a bidirectional on-board computer (OBC) control circuit with charging and discharging functions. It includes a switch module connecting the external electrical grid and the internal electrical grid, and a bidirectional on-board computer (OBC) with charging mode, inverter mode, and AC / AC mode. In the charging mode, the external electrical grid charges the bidirectional OBC through the switch module; in the inverter mode, the bidirectional OBC discharges to the external electrical grid and / or the internal electrical grid through the switch module; and in the AC / AC mode, the external electrical grid connects to the internal electrical grid through the switch module.

[0006] In one design, the switch module includes a current-limiting resistor R, a first switch K1, a second switch K2, and a third switch K3. The resistor R and the third switch K3 are connected in series and then in parallel with the first switch K1, and then the whole assembly is connected between the external electrical grid live wire L1 and the first terminal O1 of the bidirectional vehicle OBC. The second switch K2 is connected between the internal electrical grid live wire L2 and the first terminal O1 of the bidirectional vehicle OBC. The external electrical grid neutral wire N1 and the internal electrical grid neutral wire N2 are connected in parallel and then connected to the second terminal O2 of the bidirectional vehicle OBC.

[0007] The first switch K1, the second switch K2, and the third switch K3 are all single-pole single-throw relays.

[0008] The rated capacity of the second switch K2 is 20% to 80% of the rated capacity of the first switch K1, and the rated capacity of the third switch K3 is 20% to 80% of the rated capacity of the first switch K1.

[0009] In another design, the switch module includes a current-limiting resistor R, a fourth switch K4, and a fifth switch K5. The fourth switch K4 is connected between the external electrical grid live wire L1 and the first terminal O1 of the bidirectional vehicle OBC. The fifth switch K5 includes a normally closed contact, a normally open contact, and a stationary contact. The normally closed contact is connected in series with the current-limiting resistor R and then connected to the external electrical grid live wire L1. The normally open contact is connected to the internal electrical grid live wire L2. The stationary contact is connected to the first terminal O1 of the bidirectional vehicle OBC. The external electrical grid neutral wire N1 and the internal electrical grid neutral wire N2 are connected in parallel and then connected to the second terminal O2 of the bidirectional vehicle OBC.

[0010] The fourth switch K4 is a single-pole single-throw relay, and the fifth switch K5 is a single-pole double-throw relay.

[0011] The rated capacity of the fifth switch K5 is 20% to 80% of the rated capacity of the fourth switch K4.

[0012] This invention also designs a control method for a bidirectional on-board computer (OBC) control circuit with charging and discharging functions. The circuit adopts the aforementioned bidirectional on-board computer (OBC) control circuit with charging and discharging functions. The method includes: charging mode, inverter mode, and AC / AC mode. According to the selected mode, the control switch module performs corresponding actions to construct a power transmission channel. In the charging mode, the external power grid charges the bidirectional on-board computer (OBC) through the switch module. In the inverter mode, the bidirectional on-board computer (OBC) discharges to the external power grid and / or the in-vehicle power grid through the switch module. In the AC / AC mode, the external power grid is connected to the in-vehicle power grid through the switch module.

[0013] When the switching module includes a current-limiting resistor R, a first switch K1, a second switch K2, and a third switch K3; in the charging mode, the first switch K1 is closed and the second switch K2 is open; in the inverter mode, the first switch K1 is closed when discharging to the external power grid, the second switch K2 is closed when discharging to the internal power grid, and the first switch K1 and the second switch K2 are closed when discharging to both the external and internal power grids simultaneously; in the AC / AC mode, the first switch K1 and the second switch K2 are closed.

[0014] When the switching module includes a current-limiting resistor R, a fourth switch K4, and a fifth switch K5; in the charging mode, the fourth switch K4 is closed; in the inverter mode, when discharging to the external power grid, the fourth switch K4 is closed, and when discharging to the internal power grid, the normally open contact and the stationary contact of the fifth switch K5 are closed; when discharging to both the external and internal power grids simultaneously, the fourth switch K4 is closed, and the normally open contact and the stationary contact of the fifth switch K5 are closed; in the AC / AC mode, the fourth switch K4 is closed, and the normally open contact and the stationary contact of the fifth switch K5 are closed.

[0015] The beneficial effects of the technical solution provided by this invention are:

[0016] 1. When the OBC is in charging mode, a soft start is required. The AC power enters the OBC through the resistor, which buffers the OBC device and effectively prevents the OBC circuit from being damaged by the impact when the AC power is connected.

[0017] 2. When the OBC is in the in-vehicle discharge mode, the relay connected to the L line outside the vehicle is in the open state, so the vehicle charging port is completely disconnected from the circuit, which can ensure that no electric shock will occur when a person comes into contact with the charging port, thus improving safety.

[0018] 3. The number of relays is reduced and the rated capacity is reduced, effectively reducing the size and cost. Attached Figure Description

[0019] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0020] Figure 1 This is the circuit diagram of the first embodiment;

[0021] Figure 2 This is a schematic diagram of the soft start of the first embodiment;

[0022] Figure 3 This is a schematic diagram of the charging process in the first embodiment;

[0023] Figure 4 This is a schematic diagram of the first embodiment, which involves both charging and discharging inside the vehicle.

[0024] Figure 5 This is a schematic diagram of the first embodiment involving external discharge only;

[0025] Figure 6 This is a schematic diagram of the first embodiment involving in-vehicle discharge;

[0026] Figure 7 This is a schematic diagram of simultaneous discharge in the first embodiment;

[0027] Figure 8 This is the circuit diagram of the second embodiment;

[0028] Figure 9 This is a schematic diagram of the charging process in the second embodiment;

[0029] Figure 10 This is a schematic diagram of in-vehicle discharge in the second embodiment;

[0030] Figure 11 This is a schematic diagram of the second embodiment, which involves both charging and discharging inside the vehicle. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0032] This invention discloses a bidirectional on-board computer (OBC) control circuit with charging and discharging functions, comprising a switch module connecting the external power grid and the internal power grid, and a bidirectional on-board computer (OBC) having a charging mode, an inverter mode, and an AC / AC mode. In the charging mode, the external power grid charges the bidirectional on-board computer (OBC) through the switch module; in the inverter mode, the bidirectional on-board computer (OBC) discharges to the external power grid and / or the internal power grid through the switch module; and in the AC / AC mode, the external power grid is connected to the internal power grid through the switch module.

[0033] See Figure 1 The circuit diagram of the first embodiment is shown. The switch module includes a current-limiting resistor R, a first switch K1, a second switch K2, and a third switch K3. The resistor R and the third switch K3 are connected in series and then in parallel with the first switch K1. They are then connected as a whole between the external electrical grid live wire L1 and the first terminal O1 of the bidirectional vehicle OBC. The second switch K2 is connected between the internal electrical grid live wire L2 and the first terminal O1 of the bidirectional vehicle OBC. The external electrical grid neutral wire N1 and the internal electrical grid neutral wire N2 are connected in parallel and then connected to the second terminal O2 of the bidirectional vehicle OBC.

[0034] In the first embodiment, the first switch K1, the second switch K2, and the third switch K3 are all single-pole single-throw relays.

[0035] In the first embodiment, the rated capacity of the second switch K2 is 20% to 80% of the rated capacity of the first switch K1, and the rated capacity of the third switch K3 is 20% to 80% of the rated capacity of the first switch K1. This design reduces the number of relays and their rated capacity, effectively reducing size and cost, while still meeting the functional requirements of the circuit. Note: The rated capacity of a relay is the rated current that can flow through the relay or switch contacts; it is called contact capacity or contact strength.

[0036] The main circuit of the bidirectional on-board computer (OBC) is equipped with a current sensor. The controller in the bidirectional OBC provides overcurrent protection for the circuit based on the current measured by the current sensor. (See also...) Figure 1 The illustrated embodiment,

[0037] The first Hall sensor HALL1 is installed on the first terminal O1 connection line, and the second Hall sensor HALL2 is installed on the second switch K2 connection line.

[0038] Figure 2 The diagram illustrates the operation of the soft-start switch in the first embodiment. When the OBC circuit starts, a soft start is performed first. The third switch K3 is closed, while the first switch K1 and the second switch K2 are open. AC power enters the OBC after being limited by the current-limiting resistor R, preventing damage to components due to a sudden high voltage input. After the soft start is complete, the first switch K1 is closed, and the current-limiting resistor R is short-circuited. AC power then directly enters the OBC through the first switch K1. At this time, the circuit operates in charging-only mode, and its operating circuit is as follows: Figure 3 As shown.

[0039] When the OBC operates in both charging and in-vehicle discharge modes, its operating circuitry is as follows: Figure 4 As shown, the first switch K1, the second switch K2, and the third switch K3 are all closed. When the first switch K1 is closed, it connects the vehicle charging port to the OBC. When the second switch K2 is closed, it connects the in-vehicle port to the OBC. The 220V AC power is divided into two paths: one path is connected to the OBC to realize the charging function, and the other path is connected to the in-vehicle port to realize the in-vehicle discharge function.

[0040] When the OBC operates in discharge mode, it can be divided into external vehicle discharge only, internal vehicle discharge only, and simultaneous external and internal vehicle discharge. During the discharge process, the OBC discharge mode is controlled by the first switch K1 and the second switch K2, while the third switch K3 is in the open state to prevent the resistor from burning out during discharge. The working circuit for external vehicle discharge only is as follows: Figure 5 As shown, the first switch K1 is closed, and the second and third switches K2 and K3 are open. The OBC outputs 220V voltage to the charging port, and the in-vehicle port is disconnected from the circuit. The circuit for in-vehicle discharge mode is as follows: Figure 6 As shown, when the second switch K2 is closed and the first switch K1 and the third switch K3 are open, the OBC outputs voltage to the vehicle's charging port. The simultaneous opening of the first switch K1 and the third switch K3 ensures that the vehicle's charging port is not energized, improving safety. The simultaneous discharge mode circuit diagram is shown below. Figure 7 As shown, when the first switch K1 and the second switch K2 are closed and the third switch K3 is open, the OBC outputs voltage to the charging port and the in-vehicle port, realizing the function of simultaneous discharge outside and inside the vehicle.

[0041] Table 1 below shows the energized state of the OBC in-vehicle and out-of-vehicle ports when using the first embodiment. 1 indicates that the relay is in the closed state and 0 indicates that the relay is in the open state. When the OBC is in charging mode, the third switch K3 remains closed and remains open when in inverter mode. In AC / AC mode, the OBC does not work, and the energized state of the vehicle ports is de-energized.

[0042]

[0043] Note: In charging mode, the external electrical grid is always energized; in inverter mode, O1 and O2 of the OBC are always energized; in AC / AC mode, the external electrical grid is always energized.

[0044] See Figure 8 In the second embodiment shown, the switch module includes a current-limiting resistor R, a fourth switch K4, and a fifth switch K5. The fourth switch K4 is connected between the external electrical grid live wire L1 and the first terminal O1 of the bidirectional vehicle OBC. The fifth switch K5 includes a normally closed contact (NC terminal), a normally open contact (NO terminal), and a stationary contact (Common terminal). When the coil of the fifth switch K5 is not energized, the Common terminal is connected to the NC terminal by default to realize the charging or external discharge function. When the coil is energized, the Common terminal is connected to the NO terminal to realize the in-vehicle discharge function. The normally closed contact is connected in series with the current-limiting resistor R and then connected to the external electrical grid live wire L1. The normally open contact is connected to the in-vehicle electrical grid live wire L2. The stationary contact is connected to the first terminal O1 of the bidirectional vehicle OBC. The external electrical grid neutral wire N1 and the in-vehicle electrical grid neutral wire N2 are connected in parallel and then connected to the second terminal O2 of the bidirectional vehicle OBC.

[0045] In the second embodiment, the fourth switch K4 is a single-pole single-throw relay, and the fifth switch K5 is a single-pole double-throw relay.

[0046] In the second embodiment, the rated capacity of the fifth switch K5 is 20% to 80% of the rated capacity of the fourth switch K4. This design can reduce the number of relays, reduce the rated capacity of the relays, effectively reduce the size and cost, and still meet the functional requirements of the circuit.

[0047] In the second embodiment, a first Hall sensor HALL1 is installed on the first terminal O1 connection line, and a second Hall sensor HALL2 is installed on the stationary contact connection line. The Hall sensors detect the magnitude of the current in the circuit and transmit the data to the controller to provide overcurrent protection for the circuit.

[0048] When the OBC is in charging mode, its operating circuit is as follows: Figure 9As shown, the Common terminal of the fifth switch K5 is connected to the NC terminal, which connects the current-limiting resistor R to the OBC circuit. The AC power flows into the OBC through the current-limiting resistor R for soft start. After the soft start is completed, the fourth switch K4 is closed, and the AC power is connected to the OBC through the vehicle charging port to charge the car battery.

[0049] When the OBC is in both charging and in-vehicle discharge mode, its operating circuit is as follows: Figure 11 As shown, when the fourth switch K4 is closed, the Common terminal of the fifth switch K5 is switched to connect with the NO terminal, connecting the OBC and the vehicle port. At this time, the AC power passes through the fourth switch K4 to enter the OBC, and then through the fifth switch K5 to enter the vehicle port, realizing the vehicle discharge function.

[0050] When the OBC is in inverter mode, the discharge function is controlled by closing the Common, NC, and NO terminals of the fifth switch K5. When the OBC only performs external discharge, its operating circuit diagram is the same as... Figure 9 In the same manner, first close the fourth switch K4 to start the OBC's inverter mode. Closing the fourth switch K4 short-circuits the current-limiting resistor R and the fifth switch K5, allowing the OBC to supply battery voltage to the vehicle's charging port, thus enabling external discharge. When the OBC only performs in-vehicle discharge, its operating circuit is as follows: Figure 10 As shown, with the fourth switch K4 open and the Common terminal of the fifth switch K5 connected to the NO terminal, the OBC delivers battery voltage to the vehicle's internal port, enabling in-vehicle discharge. At this time, the vehicle's charging port and the OBC are completely disconnected, improving safety. When the OBC discharges simultaneously from both inside and outside the vehicle, its operating circuit is as follows: Figure 11 As shown, the fourth switch K4 is closed, and the Common terminal of the fifth switch K5 is connected to the NO terminal. The car charging port and the in-vehicle port are simultaneously connected to the OBC. When the OBC is started, the battery voltage is delivered to the car charging port and the in-vehicle port, realizing the function of simultaneous discharge inside and outside the vehicle.

[0051] Table 2 shows the energizing status of the OBC in-vehicle and out-of-vehicle ports when using the second embodiment. 1 or 0 indicates that the fourth switch K4 is in a closed or open state. NC indicates that the Common terminal of the fifth switch K5 is connected to the NC terminal. NO indicates that the Common terminal of the fifth switch K5 is connected to the NO terminal. In charging mode, the fourth switch K4 is open and the Common terminal of the fifth switch K5 is connected to the NC terminal, so the out-of-vehicle port is energized. In inverter mode, the fourth switch K4 is open and the Common terminal of the fifth switch K5 switches from being connected to the NC terminal to being connected to the NO terminal after being energized, thus realizing the in-vehicle discharge function.

[0052]

[0053] Note: In charging mode, the external electrical grid is always energized; in inverter mode, O1 and O2 of the OBC are always energized; in AC / AC mode, the external electrical grid is always energized.

[0054] This invention also discloses a control method for a bidirectional on-board computer (OBC) control circuit with charging and discharging functions. The circuit adopts the aforementioned bidirectional on-board computer (OBC) control circuit with charging and discharging functions. The method includes: a charging mode, an inverter mode, and an AC / AC mode. According to the selected mode, the control switch module performs corresponding actions to construct a power transmission channel. In the charging mode, the external power grid charges the bidirectional on-board computer (OBC) through the switch module. In the inverter mode, the bidirectional on-board computer (OBC) discharges to the external power grid and / or the internal power grid through the switch module. In the AC / AC mode, the external power grid is connected to the internal power grid through the switch module.

[0055] In the first embodiment, when the switching module includes a current-limiting resistor R, a first switch K1, a second switch K2, and a third switch K3; in the charging mode, the first switch K1 is closed and the second switch K2 is open (e.g., ...). Figure 3 (as shown); in the inverter mode, when discharging to the external power grid, the first switch K1 is closed (as shown). Figure 5 As shown), when discharging into the vehicle's electrical grid, the second switch K2 closes (as shown). Figure 6 As shown), when discharging simultaneously to both the external electrical grid and the internal electrical grid, the first switch K1 and the second switch K2 are closed (as shown). Figure 7 (as shown); in the AC / AC mode, the first switch K1 and the second switch K2 are closed (as shown). Figure 4 (As shown).

[0056] It should be noted that there will be a gradual start-up phase in the initial stage of charging mode (such as...). Figure 2 As shown, during the slow start phase, the first switch K1 opens first, the third switch K3 closes, and the current-limiting resistor R is connected in series in the charging circuit. OBC starts slowly due to current limiting. After the slow start phase ends, the first switch K1 closes, and the series current-limiting resistor R and the third switch K3 are short-circuited. The third switch K3 can be closed or opened.

[0057] In the second embodiment, when the switching module includes a current-limiting resistor R, a fourth switch K4, and a fifth switch K5; in the charging mode, the fourth switch K4 is closed (e.g., Figure 9 (as shown); In the inverter mode, when discharging to the external power grid, the fourth switch K4 closes, and when discharging to the internal power grid, the normally open contact and the stationary contact of the fifth switch K5 close (as shown). Figure 10 (as shown); when discharging simultaneously to both the external and internal electrical grids, the fourth switch K4 closes, and the normally open and stationary contacts of the fifth switch K5 close (as shown). Figure 11(as shown); In the AC / AC mode, the fourth switch K4 is closed, and the normally open contact and stationary contact of the fifth switch K5 are closed (as shown). Figure 11 (As shown).

[0058] It should be noted that there will be a gradual start-up phase in the initial stage of charging mode (such as...). Figure 8 As shown, during the slow-start phase, the fourth switch K4 opens first, and the normally closed contact and stationary contact of the fifth switch K5 close. The current-limiting resistor R is connected in series in the charging circuit, and the OBC starts slowly due to current limiting. After the slow-start phase ends, the fourth switch K4 closes, and the series current-limiting resistor R and the normally closed contact and stationary contact of the fifth switch K5 are short-circuited. The normally closed contact and stationary contact of the fifth switch K5 can be closed or opened.

[0059] The above embodiments are merely illustrative and not intended to be limiting. Any equivalent modifications or alterations made without departing from the spirit and scope of this application should be included within the scope of the claims of this application.

Claims

1. A bidirectional vehicle-mounted OBC control circuit with charging and discharging functions, characterized in that, The switch module connects the external power grid and the internal power grid, and the bidirectional vehicle-mounted OBC has a charging mode, an inversion mode and an AC / AC mode, wherein in the charging mode, the external power grid charges the bidirectional vehicle-mounted OBC through the switch module; in the inversion mode, the bidirectional vehicle-mounted OBC discharges the external power grid and / or the internal power grid through the switch module; in the AC / AC mode, the external power grid connects the internal power grid through the switch module; the switch module includes a current-limiting resistor R, a first switch K1, a second switch K2 and a third switch K3, the resistor R and the third switch K3 are connected in series, then the series connection is connected in parallel with the first switch K1, and then the whole is connected between the live wire L1 of the external power grid and the first end O1 of the bidirectional vehicle-mounted OBC; the second switch K2 is connected between the live wire L2 of the internal power grid and the first end O1 of the bidirectional vehicle-mounted OBC; the zero line N1 of the external power grid and the zero line N2 of the internal power grid are connected in parallel and then connected to the second end O2 of the bidirectional vehicle-mounted OBC, in the AC / AC mode, the first switch K1 and the second switch K2 are closed; or, the switch module includes a current-limiting resistor R, a fourth switch K4 and a fifth switch K5, the fourth switch K4 is connected between the live wire L1 of the external power grid and the first end O1 of the bidirectional vehicle-mounted OBC; the fifth switch K5 includes a movable break contact, a movable make contact and a stationary contact, the movable break contact is connected to the live wire L1 of the external power grid in series with the current-limiting resistor R, the movable make contact is connected to the live wire L2 of the internal power grid, and the stationary contact is connected to the first end O1 of the bidirectional vehicle-mounted OBC; the zero line N1 of the external power grid and the zero line N2 of the internal power grid are connected in parallel and then connected to the second end O2 of the bidirectional vehicle-mounted OBC, in the AC / AC mode, the fourth switch K4 is closed, and the movable make contact and the stationary contact of the fifth switch K5 are closed.

2. The bidirectional OBC control circuit with charge and discharge functions for vehicle according to claim 1, wherein, The first switch K1, the second switch K2 and the third switch K3 are single-pole single-throw relays.

3. The bidirectional OBC control circuit with charge and discharge functions for vehicle according to claim 2, wherein, The rated capacity of the second switch K2 is 20% to 80% of the rated capacity of the first switch K1, and the rated capacity of the third switch K3 is 20% to 80% of the rated capacity of the first switch K1.

4. The bidirectional OBC control circuit with charge and discharge functions for vehicle according to claim 1, wherein, The fourth switch K4 is a single-pole single-throw relay, and the fifth switch K5 is a single-pole double-throw relay.

5. The bidirectional OBC control circuit with charge and discharge functions for vehicle according to claim 4, characterized in that, The rated capacity of the fifth switch K5 is 20% to 80% of the rated capacity of the fourth switch K4.

6. A control method of a bidirectional vehicle-mounted OBC control circuit with charging and discharging functions, characterized by, The circuit adopts the bidirectional vehicle-mounted OBC control circuit with charging and discharging functions according to any one of claims 1 to 5, and the method includes a charging mode, an inversion mode and an AC / AC mode, according to the selected mode, the switch module makes corresponding actions to build a power transmission channel, in the charging mode, the external power grid charges the bidirectional vehicle-mounted OBC through the switch module; in the inversion mode, the bidirectional vehicle-mounted OBC discharges the external power grid and / or the internal power grid through the switch module; in the AC / AC mode, the external power grid connects the internal power grid through the switch module.

7. The control method of the bidirectional OBC control circuit with charge and discharge functions for a vehicle according to claim 6, characterized by, When the switch module includes a current-limiting resistor R, a first switch K1, a second switch K2 and a third switch K3, in the charging mode, the first switch K1 is closed, and the second switch K2 is open; In the inverter mode, the first switch K1 is closed when discharging to the external power grid, the second switch K2 is closed when discharging to the internal power grid, and the first switch K1 and the second switch K2 are closed when discharging to the external power grid and the internal power grid.

8. The control method of the bidirectional vehicle-mounted OBC control circuit with charge and discharge functions according to claim 7, characterized in that, When the switch module comprises a current-limiting resistor R, a fourth switch K4, and a fifth switch K5; In the charging mode, the fourth switch K4 is closed; In the inverter mode, the fourth switch K4 is closed when discharging to the external power grid, the movable contact and the static contact of the fifth switch K5 are closed when discharging to the internal power grid, and the fourth switch K4 is closed and the movable contact and the static contact of the fifth switch K5 are closed when discharging to the external power grid and the internal power grid.

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