Voltage conversion module for electric automobile

Abstract

The utility model belongs to the technical field of electric automobile charging, and discloses a voltage conversion module for an electric automobile, which comprises a charging input end used for being connected with a charging interface of a charging pile; the voltage conversion circuit comprises an isolation boost module, a switch circuit, a control unit and a BUCK step-down circuit, the isolation boost module and the switch circuit are respectively connected with the charging input end, the control unit is connected with the isolation boost module, the switch circuit is connected with the BUCK step-down circuit, and the isolation boost module is connected with the control unit. The BUCK step-down circuit is connected with the control unit; and the battery output end is connected with the BUCK step-down circuit, and the battery output end is used for being connected with a charging interface of an energy storage unit of the electric automobile.

Description

Technical Field

[0001] This utility model relates to the field of electric vehicle charging technology, and in particular to a voltage conversion module for electric vehicles. Background Technology

[0002] Currently, the main charging modes for electric vehicles on the market include: AC slow charging, or slow charging for short, where AC power from the power grid is converted into DC power by the on-board charger through the vehicle's AC slow charging port to charge the vehicle's power battery. The charging power is relatively low and the charging time is relatively long. DC fast charging, or fast charging for short, uses a non-on-board charger, i.e., a DC fast charging pile, to convert AC power from the power grid into DC power, and then directly charges the vehicle's power battery with high power through the vehicle's DC fast charging interface. The charging speed is fast.

[0003] Currently, for some electric vehicles with low battery pack voltage, existing DC fast charging stations often require a long time to complete the charging process. Therefore, it is necessary to design a voltage conversion module for electric vehicles to overcome the shortcomings of existing technologies. Utility Model Content

[0004] The purpose of this utility model is to overcome the shortcomings of the prior art and provide a voltage conversion module for electric vehicles, comprising:

[0005] A charging input terminal, which is used to connect to the charging interface of a charging pile;

[0006] A voltage conversion circuit, comprising an isolation boost module, a switching circuit, a control unit, and a BUCK buck circuit, wherein the isolation boost module and the switching circuit are respectively connected to the charging input terminal, the control unit is connected to the isolation boost module, the switching circuit is connected to the BUCK buck circuit, and the BUCK buck circuit is connected to the control unit;

[0007] The battery output terminal is connected to the BUCK step-down circuit and is used to connect to the charging interface of the energy storage unit of the electric vehicle.

[0008] Optionally, the BUCK step-down circuit includes a first switching transistor, a second switching transistor, a third switching transistor, a first diode, a second diode, and a third diode. The first switching transistor, the second switching transistor, and the third switching transistor are connected in parallel. The first switching transistor is connected to the first diode, the second switching transistor is connected to the second diode, and the third switching transistor is connected to the third diode.

[0009] Optionally, the first switch, the second switch, and the third switch are IGBT switches, the cathode of the diode is connected to the positive input terminal of the voltage conversion module, the anode of the diode is connected to the collector of the IGBT switch, and the emitter of the IGBT switch is connected to the negative input terminal.

[0010] Optionally, the BUCK step-down circuit further includes a first inductor, one end of which is connected to the collectors of the first switching transistor, the second switching transistor, and the third switching transistor, as well as the anodes of the first diode, the second diode, and the third diode, respectively, and the other end of which is connected to the negative terminal of the output terminal.

[0011] Optionally, the BUCK step-down circuit includes a filter circuit, which includes a first RC filter circuit, a second RC filter circuit, and a third RC filter circuit. The first RC filter circuit is connected in parallel with the first switch and the first diode, the second RC filter circuit is connected in parallel with the second switch and the second diode, and the third RC filter circuit is connected in parallel with the third switch and the third diode.

[0012] Optionally, the switching circuit includes a first relay and a second relay. One end of the first relay is connected to the positive terminal of the charging input terminal, and the other end of the first relay is connected to the BUCK step-down circuit. One end of the second relay is connected to the negative terminal of the charging input terminal, and the other end of the second relay is connected to the BUCK step-down circuit.

[0013] Optionally, it also includes a voltage measurement circuit and a current measurement circuit, with the two voltage measurement circuits connected in parallel across the two ends of the BUCK step-down circuit, and the current measurement circuit located at the output end of the BUCK step-down circuit.

[0014] Optionally, the charging input terminal further includes a low-voltage auxiliary power signal terminal and a charging connection confirmation CC2 terminal, both of which are connected to the control unit.

[0015] Optionally, it also includes an output contactor, one end of which is connected to the output terminal of the BUCK step-down circuit, and the other end of which is connected to the battery output terminal, to control the DC circuit switch for charging the battery by the charging pile.

[0016] Optionally, it also includes a heat dissipation circuit, which is a DC cooling fan connected to the control unit.

[0017] The beneficial effects of this utility model are as follows:

[0018] The voltage conversion module provided by this utility model controls the voltage and current at the output terminal of the BUCK step-down circuit for charging. It dynamically adjusts the voltage and current at the output terminal of the BUCK step-down circuit according to the BMS requirements of the electric vehicle, thereby achieving battery charging. The voltage conversion module controls and adjusts the step-down voltage and current magnitude of the BUCK step-down circuit based on the charging voltage and current requested by the vehicle's BMS, and then outputs the power to the electric vehicle battery, achieving fast charging. This allows electric vehicles whose battery output voltage is below 200V and cannot use fast charging to also be fast charged, greatly improving the user experience and expanding the user base of DC fast charging stations. Attached Figure Description

[0019] Figure 1 This is a circuit diagram of the voltage conversion module for electric vehicles provided in Embodiment 1 of this utility model;

[0020] Figure 2 This is a schematic diagram of the BUCK step-down circuit provided in Embodiment 1 of this utility model. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0022] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0025] like Figure 1 and Figure 2 As shown, this utility model provides a voltage conversion module for electric vehicles, including: a charging input terminal for connecting to the charging interface of a charging pile; a voltage conversion circuit, the voltage conversion circuit including an isolation boost module, a switching circuit, a control unit, and a BUCK buck circuit, the isolation boost module and the switching circuit being connected to the charging input terminal respectively, the control unit being connected to the isolation boost module, the switching circuit being connected to the BUCK buck circuit, and the BUCK buck circuit being connected to the control unit; and a battery output terminal connected to the BUCK buck circuit, the battery output terminal being connected to the charging interface of the energy storage unit of the electric vehicle.

[0026] In this embodiment of the present invention, the BUCK step-down circuit includes a first switch Q1, a second switch Q2, a third switch Q3, a first diode D1, a second diode D2, and a third diode D3. The first switch Q1, the second switch Q2, and the third switch Q3 are connected in parallel. The first switch Q1 is connected to the first diode D1, the second switch Q2 is connected to the second diode D2, and the third switch Q3 is connected to the third diode D3. By connecting the first switch Q1, the second switch Q2, and the third switch Q3 in parallel, a high current output is achieved. Furthermore, each switch is connected in series with a diode. When the switch is off, the current in the inductor continues to flow through the fast recovery diode, preventing sudden current surges from impacting the circuit and thus protecting it.

[0027] Specifically, the first switch Q1, the second switch Q2, and the third switch Q3 are IGBT switches. The cathode of the diode is connected to the positive terminal of the input of the voltage conversion module, the anode of the diode is connected to the collector of the IGBT switch, and the emitter of the IGBT switch is connected to the negative terminal of the input.

[0028] Furthermore, the BUCK step-down circuit also includes a first inductor L1, one end of which is connected to the collectors of the first switch Q1, the second switch Q2, and the third switch Q3, as well as the anodes of the first diode D1, the second diode D2, and the third diode D3, respectively, and the other end of the first inductor L1 is connected to the negative terminal of the output terminal.

[0029] Specifically, the BUCK step-down circuit includes a filter circuit comprising a first RC filter circuit, a second RC filter circuit, and a third RC filter circuit. The first RC filter circuit is connected in parallel with the first switch Q1 and the first diode Q1. The second RC filter circuit is connected in parallel with the second switch Q2 and the second diode D2. The third RC filter circuit is connected in parallel with the third switch Q3 and the third diode D3. The first RC filter circuit includes a first capacitor C1, a first resistor R1, a fourth capacitor C4, and a fourth resistor R4 connected in series. The second RC filter circuit includes a second capacitor C2, a second resistor R2, a fifth capacitor C5, and a fifth resistor R5 connected in series. The third RC filter circuit includes a third capacitor C3, a third resistor R3, a sixth capacitor C6, and a sixth resistor R6 connected in series. The filter circuit stabilizes the voltage during switching by using the capacitors for filtering and simultaneously discharges current through the resistors.

[0030] Specifically, in another embodiment of this utility model, the switching circuit includes a first relay K1 and a second relay K2. One end of the first relay K1 is connected to the positive terminal of the charging input terminal, and the other end of the first relay K1 is connected to the BUCK step-down circuit. One end of the second relay K2 is connected to the negative terminal of the charging input terminal, and the other end of the second relay K2 is connected to the BUCK step-down circuit.

[0031] Specifically, in another embodiment of this utility model, a voltage measurement circuit and a current measurement circuit are also included. The two voltage measurement circuits are respectively connected in parallel at both ends of the BUCK step-down circuit, and the current measurement circuit is set at the output end of the BUCK step-down circuit to measure the voltage on both sides of the BUCK step-down circuit in real time and feed it back to the control unit.

[0032] Specifically, in another embodiment of this utility model, the charging input terminal further includes a low-voltage auxiliary power signal terminal A+ / - and a charging connection confirmation terminal CC2, both of which are connected to the control unit.

[0033] Furthermore, it also includes an output contactor K3, one end of which is connected to the output terminal of the BUCK step-down circuit, and the other end of which is connected to the battery output terminal. This controls the DC circuit switch for the charging pile to charge the battery, and achieves parallel power output by controlling the output contactor.

[0034] The electric vehicle charging process involved in this utility model is as follows: when the electric vehicle is connected to a DC fast charging pile for charging, after the physical connection is completed, the low-voltage auxiliary power is turned on, and the charging handshake stage is entered; the charging parameters and charging requirements of the electric vehicle battery are identified and matched; the electric vehicle is fast-charged through the electric vehicle voltage conversion module; when the electric vehicle has finished charging, the DC fast charging pile stops charging.

[0035] Specifically, the physical connection completion, low-voltage auxiliary power supply power-on, and charging handshake stages are manifested as follows: when the electric vehicle is connected to a DC fast charging pile for charging, the voltage conversion module performs physical connection identification, confirms the resistance value of the CC2 terminal and the voltage of the low-voltage auxiliary power supply signal A+ / - based on the charging connection, and thereby determines whether the physical connection is completed.

[0036] After the physical connection of the DC fast charging pile is identified, the low-voltage auxiliary power supply is powered on and begins to periodically send handshake messages. The voltage conversion module is awakened by the low-voltage auxiliary power supply and communicates with the electric vehicle and the DC fast charging pile respectively, and sends the results to the vehicle CAN bus. The voltage conversion module responds to the CHM handshake signal of the DC fast charging pile and sends a BHM handshake message.

[0037] Specifically, the voltage conversion module needs to be enabled under the following conditions: after the voltage conversion module completes the identification of the electric vehicle battery charging parameters and confirms that it is connected to the DC fast charging pile, if the electric vehicle battery charging parameter voltage is lower than DC200V, the electric vehicle needs to achieve fast charging through the voltage conversion module.

[0038] The voltage conversion module is installed inside the DC fast charging pile. Both the electric vehicle and the DC fast charging pile are connected to the voltage conversion module. Specifically, one end of the BUCK step-down circuit is connected to the fast charging power source inside the DC fast charging pile, and the other end of the BUCK step-down circuit is connected to the battery of the electric vehicle.

[0039] Specifically, the voltage conversion module operates as follows: when a battery voltage below 200V is fed back to the voltage conversion module for charging, the module, after vehicle and self-identification via the control unit, activates through a CAN communication message from the control unit, thus engaging the BUCK step-down circuit. The control unit simulates a required battery voltage of 300V. The charging pile detects this simulated 300V and sends a request signal to output 310V, 50A DC power as the input source for the BUCK step-down circuit. The voltage conversion module charges the battery by controlling the output voltage and current of the BUCK step-down circuit, dynamically adjusting these parameters according to the electric vehicle's BMS requirements. The voltage conversion module, based on the charging voltage and current requested by the vehicle's BMS, controls the step-down voltage and current of the BUCK step-down circuit to charge the battery.

[0040] Specifically, in another embodiment of this utility model, a heat dissipation circuit is also included. The heat dissipation circuit is a DC cooling fan, which is connected to the control unit. The heat dissipation circuit is used to dissipate heat for the voltage conversion module.

[0041] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A voltage conversion module for an electric vehicle, characterized by comprising: include: A charging input terminal, which is used to connect to the charging interface of a charging pile; A voltage conversion circuit, comprising an isolation boost module, a switching circuit, a control unit, and a BUCK buck circuit, wherein the isolation boost module and the switching circuit are respectively connected to the charging input terminal, the control unit is connected to the isolation boost module, the switching circuit is connected to the BUCK buck circuit, and the BUCK buck circuit is connected to the control unit; The battery output terminal is connected to the BUCK step-down circuit and is used to connect to the charging interface of the energy storage unit of the electric vehicle.

2. The voltage conversion module for an electric vehicle of claim 1, wherein, The BUCK step-down circuit includes a first switch, a second switch, a third switch, a first diode, a second diode, and a third diode. The first switch, the second switch, and the third switch are connected in parallel. The first switch is connected to the first diode, the second switch is connected to the second diode, and the third switch is connected to the third diode.

3. The voltage conversion module for an electric vehicle of claim 2, wherein, The first, second, and third switching transistors are IGBT switching transistors. The cathode of the diode is connected to the positive input terminal of the voltage conversion module, the anode of the diode is connected to the collector of the IGBT switching transistor, and the emitter of the IGBT switching transistor is connected to the negative input terminal.

4. The voltage conversion module for an electric vehicle of claim 3, wherein, The BUCK step-down circuit also includes a first inductor, one end of which is connected to the collectors of the first switching transistor, the second switching transistor, and the third switching transistor, as well as the anodes of the first diode, the second diode, and the third diode, respectively, and the other end of which is connected to the negative terminal of the output terminal.

5. The voltage conversion module for an electric vehicle of claim 3, wherein, The BUCK step-down circuit includes a filter circuit, which includes a first RC filter circuit, a second RC filter circuit, and a third RC filter circuit. The first RC filter circuit is connected in parallel with the first switch and the first diode. The second RC filter circuit is connected in parallel with the second switch and the second diode. The third RC filter circuit is connected in parallel with the third switch and the third diode.

6. The voltage conversion module for an electric vehicle of claim 1, wherein, The switching circuit includes a first relay and a second relay. One end of the first relay is connected to the positive terminal of the charging input terminal, and the other end of the first relay is connected to the BUCK step-down circuit. One end of the second relay is connected to the negative terminal of the charging input terminal, and the other end of the second relay is connected to the BUCK step-down circuit.

7. The voltage conversion module for an electric vehicle of claim 1, wherein, It also includes a voltage measurement circuit and a current measurement circuit. The two voltage measurement circuits are respectively connected in parallel at both ends of the BUCK step-down circuit, and the current measurement circuit is located at the output end of the BUCK step-down circuit.

8. The voltage conversion module for electric vehicles according to claim 1, characterized in that, The charging input terminal also includes a low-voltage auxiliary power signal terminal and a charging connection confirmation CC2 terminal, both of which are connected to the control unit.

9. The voltage conversion module for an electric vehicle of claim 8, wherein, It also includes an output contactor, one end of which is connected to the output terminal of the BUCK step-down circuit, and the other end of which is connected to the battery output terminal, controlling the DC circuit switch for the charging pile to charge the battery.

10. The voltage conversion module for an electric vehicle of claim 1, wherein, It also includes a heat dissipation circuit, which is a DC cooling fan connected to the control unit.

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