Direct-current-to-alternating-current discharging device

Abstract

The utility model discloses a direct current-to-alternating current discharging device, which is adapted to a direct current charging port of an electric automobile and comprises a monitoring unit and a power supply unit, the monitoring unit comprises a control guide circuit, a main controller, a power controller and a fault monitoring circuit which are sequentially connected in series; the control guide circuit is connected to a signal end of the direct current charging port and is used for data interaction between the main controller and the electric vehicle; the power supply unit comprises an insulation detection circuit, a pre-charging circuit and an inverter circuit which are sequentially connected in series; the insulation detection circuit is connected to the power supply end of the direct current charging port, and the insulation detection circuit and the pre-charging circuit are connected with the main controller and used for insulation detection and current impact protection; the control end and the output end of the inverter circuit are respectively connected with the power controller, and the inverter circuit is used for controlling and monitoring alternating current output; the system has the characteristics of high integration degree, high safety and high reliability.

Description

Technical Field

[0001] The utility model relates to the technical field of electric vehicles, in particular to a direct current to alternating current discharge device. Background Art

[0002] In terms of energy utilization of electric vehicles, in addition to traditional on-board energy consumption, the emerging V2L (Vehicle-to-Load) technology is gradually becoming a hot spot for research and application. V2L technology allows electric vehicles to provide power to external devices through their on-board batteries, realizing energy conversion and application from "vehicle end to load". In the existing technology, if new energy vehicles do not have a built-in discharge function, they are usually equipped with a portable discharge device. The design of this discharge device must meet specific technical requirements to ensure effective communication with the vehicle battery management system (BMS) and safe energy conversion.

[0003] At present, the mainstream discharge device adopts the vehicle AC port, which realizes external discharge by connecting a discharge socket through the discharge function of the bidirectional OBC (On-Board Charger) in the vehicle. Figure 1 This solution has the following disadvantages:

[0004] Lack of versatility: Currently, many new energy vehicles are only equipped with DC ports, and the existing discharge devices rely on the vehicle's AC port and the discharge function of the two-way OBC, which limits the scope of application of the discharge device and is not applicable to models equipped with only DC ports. Risks are concentrated on the OBC in the car: The discharge socket strip is only used as a power supply, and all risks (such as short circuit of external electrical appliances, etc.) must be borne by the OBC in the car. This not only tests the fault detection capability of the OBC, but also once a fault occurs, it may cause damage to the OBC in the car, resulting in high repair costs. Lack of independent risk control: The discharge socket strip itself does not have power output control and fault monitoring functions, which increases the burden on the OBC in the car and also reduces the safety of the discharge process. Utility Model Content

[0005] The purpose of the utility model is to overcome the deficiencies in the prior art, provide a direct current to alternating current discharge device, and solve the drawbacks of the prior art discharge device mentioned in the background technology.

[0006] In order to achieve the above purpose, the utility model is implemented by adopting the following technical solutions:

[0007] The utility model provides a discharge device for converting direct current to alternating current. The discharge device is adapted to a direct current charging port of an electric vehicle and comprises a monitoring unit and a power supply unit; the monitoring unit comprises a control guidance circuit, a main controller, a power controller and a fault monitoring circuit which are sequentially connected in series; the control guidance circuit is connected to a signal end of the direct current charging port and is used for the main controller to perform data interaction with the electric vehicle; the power supply unit comprises an insulation detection circuit, a pre-charging circuit and an inverter circuit which are sequentially connected in series; the insulation detection circuit is connected to the power supply end of the direct current charging port, and the insulation detection circuit and the pre-charging circuit are connected to the main controller for insulation detection and current impact protection; the control end and the output end of the inverter circuit are respectively connected to the power controller for alternating current output control and monitoring.

[0008] Optionally, the control guidance circuit includes a CC1 acquisition circuit and a CAN communication circuit; the CC1 acquisition circuit is connected between the CC1 port of the DC charging port and the serial port of the main controller, and is used to collect CC1 signals and determine whether the power supply unit and the DC charging port are connected normally according to the CC1 signals;

[0009] The CAN communication circuit is connected between the S+ / S- port of the DC charging port and the serial port of the main controller, and is used for data interaction between the main controller and the BMS of the electric vehicle in the discharge handshake stage, the discharge parameter configuration stage and the discharge request stage.

[0010] Optionally, the main controller adopts an MCU chip, and the power controller adopts a DSP chip.

[0011] Optionally, the fault monitoring circuit includes a leakage monitoring module, a short circuit monitoring module and a temperature monitoring module arranged on the output side of the inverter circuit, and is used for leakage, short circuit and temperature monitoring.

[0012] Optionally, the insulation detection circuit includes a resistor string, a voltage-dividing resistor and a first voltage acquisition circuit, the resistor string and the voltage-dividing resistor are connected in series between the positive and negative poles of the power supply end of the DC charging port, the input end of the first voltage acquisition circuit is connected to the common end of the resistor string and the voltage-dividing resistor, and the output end of the first voltage acquisition circuit is connected to the serial port of the main controller.

[0013] Optionally, the pre-charging circuit includes a pre-charging resistor, a path switching circuit, a second voltage acquisition circuit and a third voltage acquisition circuit; the power supply line between the insulation detection circuit and the inverter circuit is recorded as the first branch; the pre-charging resistor is connected in parallel to the pre-charging section power supply line and is recorded as the second branch; the path switching circuit is connected in series to the first branch and the second branch, and is used to switch the first branch or the second branch on; the input ends of the second voltage acquisition circuit and the third voltage acquisition circuit are respectively connected to the two ends of the pre-charging resistor, and the output ends of the second voltage acquisition circuit and the third voltage acquisition circuit are respectively connected to the serial port of the main controller.

[0014] Optionally, the inverter circuit includes a MOS tube drive circuit and a full-bridge inverter circuit, the input end of the MOS tube drive circuit is connected to the PWM output end of the power controller, the output end of the MOS tube drive circuit is connected to the control end of the full-bridge inverter circuit, and the input end of the full-bridge inverter circuit is connected to the output end of the pre-charging circuit.

[0015] Optionally, the monitoring unit further includes a remote transmission module connected to the main controller, and the remote transmission module is used for remote data communication.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] The utility model provides a DC-to-AC discharge device, which adopts an integrated solution, is independent of the vehicle-mounted OBC, and by virtue of the strong and stable load capacity of the DC port, all risks are avoided outside the vehicle as much as possible. The power output control, fault monitoring and response are completed by the discharge device itself, and at the same time, the user can understand the discharge process information more clearly through the remote transmission module. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural block diagram of an existing discharge device provided by the background technology of the utility model;

[0019] Figure 2 It is a structural block diagram of a DC to AC discharge device provided in an embodiment of the utility model;

[0020] Figure 3 It is a circuit schematic diagram of a CAN communication circuit provided by an embodiment of the utility model;

[0021] Figure 4 It is a circuit schematic diagram of the CC1 acquisition circuit provided by the embodiment of the utility model;

[0022] Figure 5 It is a circuit principle diagram of the insulation detection circuit provided by the embodiment of the utility model;

[0023] Figure 6 It is a circuit schematic diagram of a pre-charging circuit provided by an embodiment of the utility model;

[0024] Figure 7 It is a circuit principle diagram of a MOS tube driving circuit provided by an embodiment of the utility model;

[0025] Figure 8 It is a circuit principle diagram of a full-bridge inverter circuit provided by an embodiment of the utility model;

[0026] Fig. 9 It is a circuit schematic diagram of the leakage monitoring module provided by the embodiment of the utility model;

[0027] Fig.10 It is a circuit schematic diagram of the temperature monitoring module provided by the embodiment of the utility model;

[0028] Fig.11 It is a circuit schematic diagram of a short circuit monitoring module provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0029] The utility model is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and cannot be used to limit the protection scope of the utility model.

[0030] Embodiment 1:

[0031] like Figure 2 As shown, the embodiment of the utility model provides a DC to AC discharge device, which is adapted to the DC charging port of an electric vehicle, and includes a monitoring unit and a power supply unit; the monitoring unit includes a control guide circuit, a main controller, a power controller, and a fault monitoring circuit connected in series in sequence; the control guide circuit is connected to the signal end of the DC charging port, and is used for data exchange between the main controller and the electric vehicle; the power supply unit includes an insulation detection circuit, a pre-charge circuit, and an inverter circuit connected in series in sequence; the insulation detection circuit is connected to the power supply end of the DC charging port, and the insulation detection circuit and the pre-charge circuit are connected to the main controller for insulation detection and current impact protection; the control end and the output end of the inverter circuit are respectively connected to the power controller for AC output control and monitoring. The monitoring unit also includes a remote transmission module connected to the main controller, and the remote transmission module is used for remote data communication.

[0032] Specifically in this embodiment, the main controller uses an MCU chip, and the power controller uses a DSP chip. In other optional embodiments, the processor type can be adjusted as needed.

[0033] Specifically in this embodiment, the control guidance circuit includes a CC1 acquisition circuit and a CAN communication circuit; the CC1 acquisition circuit is connected between the CC1 port of the DC charging port and the serial port of the main controller, and is used to collect CC1 signals and determine whether the power supply unit and the DC charging port are connected normally according to the CC1 signals; the CAN communication circuit is connected between the S+ / S- port of the DC charging port and the serial port of the main controller, and is used for data interaction between the main controller and the BMS of the electric vehicle in the discharge handshake stage, the discharge parameter configuration stage and the discharge request stage.

[0034] like Figure 3 As shown, the CAN communication circuit adopts the CAN bus receiver U1 of the HGA1040M model, the TXD end of the CAN bus receiver U1 is connected to the main controller via the resistor R4, the RXD end of the CAN bus receiver U1 is grounded via the resistors R2 and R3, the common end of the resistors R2 and R3 is connected to the main controller via the resistor R1, the RS end of the CAN bus receiver U1 is grounded via the resistor R5, the VCC end of the CAN bus receiver U1 is connected to the power supply, and is grounded via the capacitor C1; the CAN bus receiver U The CANH terminal and CANL terminal of 1 are connected to the S+ / S- port of the DC charging port through the resistor R6 and the resistor R7 respectively, and the two ends of the common mode inductor L1 are connected in parallel with the resistor R6 and the resistor R7 respectively; the resistor R8 and the resistor R9, the transient suppression diode D1 and the TVS transient suppression diode D2 are respectively connected in series between the S+ / S- ports, and the common end of the transient suppression diode D1 and the TVS transient suppression diode D2 is respectively connected to the S+ / S- port, the common end of the resistor R8 and the resistor R9, and the ground wire through the capacitors C2, C3, and C4.

[0035] like Figure 4 As shown, the CC1 acquisition circuit adopts an operational amplifier U2 of the LMV321 model, and the output end of the operational amplifier U2 enters the main controller through an RC filter circuit composed of a resistor R14 and a capacitor C6; the negative input end of the operational amplifier U2 is short-circuited with the output end, and the positive input end of the operational amplifier U2 is connected to the power supply through resistors R12, R11, and R10, and the common end of the resistor R10 and the resistor R11 is connected to the CC1 port of the DC charging port to receive the CC1 signal, and the two ends of the resistor R11 are grounded through a diode D3 and a capacitor C7, and the positive input end of the operational amplifier U2 is grounded through a resistor R13 and a capacitor C5.

[0036] Specifically in this embodiment, the insulation detection circuit includes a resistor string, a voltage-dividing resistor and a first voltage acquisition circuit. The resistor string and the voltage-dividing resistor are connected in series between the positive and negative poles of the power supply end of the DC charging port. The input end of the first voltage acquisition circuit is connected to the common end of the resistor string and the voltage-dividing resistor, and the output end of the first voltage acquisition circuit is connected to the serial port of the main controller.

[0037] like Figure 5 As shown, the resistor string includes resistors R21, R22, R23, R24, R25 and R26. The resistor string is composed of multiple resistors: if one resistor is used to withstand high voltage, it will generate a lot of heat. Once it is broken down, the subsequent low-voltage circuit will be damaged. Even if individual resistors in the resistor string are broken, it will not affect the subsequent circuits. Only sampling will cause errors. At the same time, each resistor is shunted, and the heat generation will be greatly reduced. The voltage-dividing resistor is resistor R18, and the first voltage acquisition circuit includes an operational amplifier U3, a resistor R20, a resistor R19, and a capacitor C8. The output end of the operational amplifier U3 enters the main controller through an RC filter circuit composed of resistor R20 and capacitor C8; the negative input end of the operational amplifier U3 is short-circuited with the output end, and the positive input end of the operational amplifier U3 is connected to the DC+ port of the DC charging port through resistor R19, relay K1, and a resistor string. The two ends of the resistor R19 are grounded through resistor R18 and capacitor C9 respectively, and the common ends of the resistor R18 and the resistor R19 are also grounded through diodes D4 and diodes D5 respectively; the control circuit of relay K1 includes resistor R15, diode D6, transistor Q1, resistor R16 and resistor R14, the collector of the transistor Q1 is connected to the power supply through the coil of relay K1 and resistor R15, the diode D6 is connected in parallel to the two ends of the coil of relay K1, the base of the transistor Q1 is connected to the main controller and the ground wire through resistor R16 and resistor R17 respectively, and the emitter of the transistor Q1 is grounded. By controlling the relay K1 to open / close, the insulation resistance value is calculated from different AD sampling values ​​to determine whether the insulation of the device input end is good.

[0038] Specifically in this embodiment, the pre-charging circuit includes a pre-charging resistor, a path switching circuit, a second voltage acquisition circuit and a third voltage acquisition circuit; the power supply line between the insulation detection circuit and the inverter circuit is recorded as the first branch; the pre-charging resistor is connected in parallel to the pre-charging section power supply line and is recorded as the second branch; the path switching circuit is connected in series to the first branch and the second branch, and is used to switch the first branch or the second branch on; the input ends of the second voltage acquisition circuit and the third voltage acquisition circuit are respectively connected to the two ends of the pre-charging resistor, and the output ends of the second voltage acquisition circuit and the third voltage acquisition circuit are respectively connected to the serial port of the main controller.

[0039] like Figure 6As shown, the pre-charging resistor is a resistor R34 and a resistor R35 connected in series, the path switching circuit includes relay K2, relay K3, and relay K4, and relay K4 is set on the DC+ line. The control circuit of relay K4 includes diode D7, resistor R27, resistor R28, and resistor R29. One end of the coil of relay K4 is connected to the main controller, and the other end is grounded through resistor R27, resistor R28, and resistor R29 respectively. The diode D7 is connected in parallel to the two ends of the coil of relay K4; relay K2 is connected in series with the pre-charging resistor and then connected in parallel with relay K4. The control circuit of the electrical appliance K2 includes a diode D8 and a resistor R30. One end of the coil of the relay K2 is connected to the main controller, and the other end is grounded through the resistor R30. The diode D8 is connected in parallel to both ends of the coil of the relay K2. The relay K3 is set on the DC-line. The control circuit of the relay K3 includes a diode D9, a resistor R31, a resistor R32, and a resistor R33. One end of the coil of the relay K3 is connected to the main controller, and the other end is grounded through the resistor R31, the resistor R32, and the resistor R33. The diode D9 is connected in parallel to both ends of the coil of the relay K3. The pre-charging resistor, that is, the resistors R34 and R35 are cement resistors. When the DC high voltage is input, the circuit first closes the K2 and K3 relays to pre-charge the pre-charging resistor. When the pressure difference before and after the pre-charging resistor is less than 20V, the K4 relay is closed and the K2 relay is opened at the same time. The pre-charging is completed, which effectively avoids the current shock.

[0040] Specifically in this embodiment, the inverter circuit includes a MOS tube drive circuit and a full-bridge inverter circuit. The input end of the MOS tube drive circuit is connected to the PWM output end of the power controller, the output end of the MOS tube drive circuit is connected to the control end of the full-bridge inverter circuit, and the input end of the full-bridge inverter circuit is connected to the output end of the pre-charging circuit.

[0041] like Figure 7 As shown in the figure, the MOS tube drive circuit is composed of U4, U5 high-speed power MOSFET and IGBT drive chip ID7S625, and the full-bridge inverter circuit driven by it is as follows Figure 8 As shown, the SPWM (sinusoidal pulse width modulation) signal generated by the power processor simulates a sine wave by continuously updating the value of the PWM comparison register.

[0042] Specifically in this embodiment, the fault monitoring circuit includes a leakage monitoring module, a short circuit monitoring module and a temperature monitoring module arranged at the output side of the inverter circuit, and is used for leakage, short circuit and temperature monitoring.

[0043] like Fig. 9 As shown, the leakage monitoring module adopts the leakage current transformer SFG-CPL-A4 of Ximagnetic, which is connected to the leakage self-detection pin of the power controller. After sampling and processing by the power controller, the real DC / AC component leakage is obtained.

[0044] like Fig.10 As shown, the temperature monitoring module includes arranging NTC sensors at the MOS tube, inductor, and inner wall of the device of the MOS tube driving circuit to perform temperature sampling.

[0045] like Fig.11 As shown, the short-circuit monitoring module adopts the CC6921 current sampling chip, which is connected to the short-circuit detection reading pin of the power controller. The power controller obtains the short-circuit state after sampling and processing.

[0046] The DC-to-AC discharge device provided in this embodiment determines whether the gun is correctly inserted into the vehicle's DC charging port by detecting whether the CC1 signal at the gun end is connected OK. When the connection is reliable, the insulation detection stage will be carried out, and then the pre-charging circuit will pre-charge the input of the device to reduce the current impact. The main control MCU is connected to the BMS through the S+ / S- signal interface to realize the CAN message interaction in the discharge handshake stage, the discharge parameter configuration stage and the discharge request stage, and realizes the unification of the discharge voltage and current at the vehicle end and the device end, as well as the response of the vehicle being ready. At the same time, the main control MCU transmits the power output signal to the power DSP, which realizes the PWM pulse width modulation and duty cycle adjustment of the MOS tube drive circuit, and at the same time, the voltage and current and other parameters sampled through the fault monitoring process are controlled by the PID closed-loop control algorithm to achieve the stable output of AC 220V, ensuring the constant output power.

[0047] Fault monitoring is responsible for temperature, short circuit and leakage status detection during the discharge process to ensure high safety of the discharge process. At the same time, the main control MCU realizes multiple user access forms through the remote transmission module. Users can read discharge parameters and fault status information through Bluetooth, 4G and other methods. Finally, a stable and reliable DC to AC discharge output is achieved.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A DC to AC discharge device, the discharge device is adapted to the DC charging port of an electric vehicle, characterized in that: It includes a monitoring unit and a power supply unit; the monitoring unit includes a control guidance circuit, a main controller, a power controller and a fault monitoring circuit connected in series in sequence; the control guidance circuit is connected to the signal end of the DC charging port, and is used for the main controller to exchange data with the electric vehicle; the power supply unit includes an insulation detection circuit, a pre-charging circuit and an inverter circuit connected in series in sequence; the insulation detection circuit is connected to the power supply end of the DC charging port, and the insulation detection circuit and the pre-charging circuit are connected to the main controller for insulation detection and current impact protection; the control end and the output end of the inverter circuit are respectively connected to the power controller for AC output control and monitoring; the fault monitoring circuit includes a leakage monitoring module, a short circuit monitoring module and a temperature monitoring module arranged on the output side of the inverter circuit, which are used for leakage, short circuit and temperature monitoring; the monitoring unit also includes a remote transmission module connected to the main controller, and the remote transmission module is used for remote data communication.

2. The DC-to-AC discharge device according to claim 1, characterized in that: The control guidance circuit includes a CC1 acquisition circuit and a CAN communication circuit; the CC1 acquisition circuit is connected between the CC1 port of the DC charging port and the serial port of the main controller, and is used to collect CC1 signals and determine whether the power supply unit and the DC charging port are connected normally according to the CC1 signals; The CAN communication circuit is connected between the S+ / S- port of the DC charging port and the serial port of the main controller, and is used for data interaction between the main controller and the BMS of the electric vehicle in the discharge handshake stage, the discharge parameter configuration stage and the discharge request stage.

3. The DC-to-AC discharge device according to claim 1, characterized in that: The main controller adopts an MCU chip, and the power controller adopts a DSP chip.

4. The DC-to-AC discharge device according to claim 1, characterized in that: The insulation detection circuit includes a resistor string, a voltage-dividing resistor and a first voltage acquisition circuit. The resistor string and the voltage-dividing resistor are connected in series between the positive and negative poles of the power supply end of the DC charging port. The input end of the first voltage acquisition circuit is connected to the common end of the resistor string and the voltage-dividing resistor, and the output end of the first voltage acquisition circuit is connected to the serial port of the main controller.

5. The DC-to-AC discharge device according to claim 1, characterized in that: The pre-charging circuit includes a pre-charging resistor, a path switching circuit, a second voltage acquisition circuit and a third voltage acquisition circuit; the power supply line between the insulation detection circuit and the inverter circuit is recorded as the first branch; the pre-charging resistor is connected in parallel to the pre-charging section power supply line and is recorded as the second branch; the path switching circuit is connected in series to the first branch and the second branch, and is used to switch the first branch or the second branch on; the input ends of the second voltage acquisition circuit and the third voltage acquisition circuit are respectively connected to the two ends of the pre-charging resistor, and the output ends of the second voltage acquisition circuit and the third voltage acquisition circuit are respectively connected to the serial port of the main controller.

6. The DC-to-AC discharge device according to claim 1, characterized in that: The inverter circuit includes a MOS tube drive circuit and a full-bridge inverter circuit, the input end of the MOS tube drive circuit is connected to the PWM output end of the power controller, the output end of the MOS tube drive circuit is connected to the control end of the full-bridge inverter circuit, and the input end of the full-bridge inverter circuit is connected to the output end of the pre-charging circuit.

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