V2G inverter control method and device

Abstract

The invention discloses a V2G inverter control method and device, and relates to the field of electric automobiles, a V2G inverter is composed of a direct current charging gun, a control unit, a protocol and interaction unit, a power inversion unit, a drive control unit, a built-in battery and an auxiliary power supply, the electric automobile high-voltage battery inverts the mains supply to take electricity, and control loop parameters are adjusted in time according to load properties, so that the electric automobile charging efficiency is improved. And output waveform distortion is reduced, waveform quality is improved, and heating and harmonic pollution are reduced.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicles, and in particular to a V2G inverter control method and device. Background Art

[0002] At present, new energy electric vehicles are gradually entering thousands of households. Compared with traditional fuel vehicles, electric vehicles can realize more application scenarios and are more convenient for people's lives. For example, they can discharge AC or DC to the outside through some equipment to achieve self-use of electricity, emergency power generation, etc., and can be connected to the grid or off-grid.

[0003] At present, the distortion degree of the output voltage waveform of the V2G inverter under different loads is different. Generally, the waveform quality is better under pure resistive load, the power factor is close to 1, and the output voltage waveform is closer to the standard sine wave. The waveform distortion is more serious under nonlinear load, and the harmonic content is higher, causing the equipment to generate more heat, such as rectifier load (also the load type of most household equipment), nonlinear arc equipment, and equipment with ferromagnetic characteristics.

[0004] Even though there are inverter control methods for nonlinear loads, such as multiple quasi-resonant controllers, the V2G working environment is diverse, and the uncertainty caused by temperature rise and component parameter drift makes the original controller no longer have the optimal control effect. This requires the controller to have stronger robustness and a wider range of application. Summary of the invention

[0005] In order to overcome the shortcomings of the above technologies, the present invention provides a V2G inverter control method and device that improves waveform quality and reduces heat generation and harmonic pollution. The technical solution adopted by the present invention to overcome the technical problems is: A V2G inverter control method, the V2G inverter is composed of a DC charging gun, a control unit, a protocol and interaction unit, a power inverter unit, a drive control unit, a built-in battery, and an auxiliary power supply. The control method is: The control unit collects the drive fault signal and outputs the SPWM control signal to the drive control unit; The drive control unit amplifies the SPWM control signal and outputs it to the power inverter unit; The power inverter unit converts the DC power of the vehicle's power battery into AC power to supply the load; The control unit collects the input voltage, output voltage and current signals of the power inverter unit for closed-loop calculation; The protocol and interaction unit displays the current status, fault information, input data, and output data; When the start switch is closed, the built-in battery supplies power to the protocol and interaction unit, the control unit, and the drive control unit. The protocol and interaction unit communicates with the vehicle BMS to close the PDU, allowing the power battery to output to the power inverter unit.

[0006] Furthermore, the power inverter unit converts the DC power of the vehicle's power battery into 220V AC power.

[0007] Furthermore, the protocol and interaction unit communicates with the cloud platform via a 4G module.

[0008] Furthermore, the control unit stores dual closed-loop control parameters for loads with different characteristics.

[0009] Furthermore, the dual closed-loop control parameters are divided into parameters for linear load, parameters when the power factor is greater than or equal to 0.8 and the load impedance is capacitive, parameters when the power factor is greater than or equal to 0.8 and the load impedance is inductive, parameters when the power factor is less than or equal to 0.8 and the load impedance is capacitive, parameters when the power factor is less than or equal to 0.8 and the load impedance is inductive, parameters when the temperature rise is less than or equal to 40°C, and parameters when the temperature rise is greater than or equal to 40°C.

[0010] Furthermore, when powered on, the control unit loads dual closed-loop control parameters and runs dual closed-loop control, outputting corresponding bipolar or unipolar double-frequency SPWM signals to the drive control unit, and the drive control unit controls the power inverter unit to output 50Hz, 220V single-phase AC mains.

[0011] Furthermore, the input voltage, input current, output voltage, output current, overvoltage fault signal, overcurrent fault information, and overtemperature fault signal of the power inverter unit are collected. When the power inverter unit detects the output current, the DFT algorithm is run to calculate the harmonic content THD of the voltage waveform of N cycles, and the phase difference is calculated based on the collected input voltage, input current, output voltage, and output current, and the power factor is calculated based on the phase difference.

[0012] Furthermore, when each parameter in the dual closed-loop control parameter is switched, the overshoot is less than 5% and the adjustment time is less than 5ms.

[0013] On the other hand, the present invention also relates to a V2G inverter control device, comprising: a control unit, a protocol and interaction unit, a power inverter unit, a drive control unit, a built-in battery, and an auxiliary power supply, wherein the built-in battery is respectively connected to the protocol and interaction unit, the auxiliary power supply output side, the drive control unit and the control unit through a switch; the control unit is connected to the drive control unit, the power inverter unit, the protocol and interaction unit; the input side of the power inverter unit is connected to the DC bus of the charging gun, and the output side is connected to the load interface and the auxiliary power supply; the protocol and interaction unit is connected to the charging gun signal line.

[0014] The beneficial effects of the present invention are: realizing the inverter of the electric vehicle high-voltage battery to obtain electricity from the mains, timely adjusting the control loop parameters according to the load properties, reducing the output waveform distortion, improving the waveform quality and reducing heat generation and harmonic pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a structural diagram of the V2G inverter of the present invention; Figure 2 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0016] The following is combined with Figure 1 , Attachment Figure 2 The present invention is further described.

[0017] Example 1 A V2G inverter control method, the V2G inverter is composed of a DC charging gun, a control unit, a protocol and interaction unit, a power inverter unit, a drive control unit, a built-in battery, and an auxiliary power supply. The control method is: The control unit collects the drive fault signal and outputs the SPWM control signal to the drive control unit; The drive control unit amplifies the SPWM control signal and outputs it to the power inverter unit; The power inverter unit converts the DC power of the vehicle's power battery into AC power to supply the load; The control unit collects the input voltage, output voltage and current signals of the power inverter unit for closed-loop calculation; The protocol and interaction unit displays the current status, fault information, input data, and output data; When the start switch is closed, the built-in battery supplies power to the protocol and interaction unit, the control unit, and the drive control unit. The protocol and interaction unit communicates with the vehicle BMS to close the PDU, allowing the power battery to output to the power inverter unit.

[0018] In this embodiment, the power inverter unit inverts the DC power of the vehicle power battery into 220V AC power.

[0019] In this embodiment, the protocol and interaction unit communicates with the cloud platform through a 4G module, supporting operations such as viewing mini-program information and remote control on the mobile phone.

[0020] In this embodiment, the control unit stores dual closed-loop control parameters for loads with different characteristics that are pre-set offline. The dual closed-loop control parameters are divided into parameters for linear loads, parameters when the power factor is greater than or equal to 0.8 and the load impedance is capacitive, parameters when the power factor is greater than or equal to 0.8 and the load impedance is inductive, parameters when the power factor is less than or equal to 0.8 and the load impedance is capacitive, parameters when the power factor is less than or equal to 0.8 and the load impedance is inductive, parameters when the temperature rise is less than or equal to 40°C, and parameters when the temperature rise is greater than or equal to 40°C, so as to consider the influence of temperature rise on parameter drift.

[0021] In this embodiment, when powered on, the control unit loads the dual closed-loop control parameters and runs the dual closed-loop control, outputting the corresponding bipolar or unipolar double-frequency SPWM signal to the drive control unit, and the drive control unit controls the power inverter unit to output 50Hz, 220V single-phase AC mains.

[0022] In this embodiment, the input voltage, input current, output voltage, output current, overvoltage fault signal, overcurrent fault information, and overtemperature fault signal of the power inverter unit are collected. When the power inverter unit detects the output current, the DFT algorithm is run to calculate the harmonic content THD of the voltage waveform of N cycles, and the phase difference is calculated based on the collected input voltage, input current, output voltage, and output current. The power factor is calculated based on the phase difference to determine the nonlinear load and load impedance characteristics. Combined with the temperature rise, harmonic content, power factor, and impedance characteristics, appropriate controller parameters are selected to improve the output waveform quality.

[0023] In this embodiment, the overshoot of each parameter in the dual closed-loop control parameters is less than 5% and the adjustment time is less than 5ms when switching. This is to realize that after the device is powered on in advance to identify the nature of the load, it can quickly switch the controller parameters when the output voltage passes through zero point based on the above-collected parameters to prevent impact and power outage during switching; it can quickly switch and select when the program is running, without the need for adaptive algorithm to adjust parameters, to prevent unexpected control effects. This control method is simple to execute and can quickly and effectively adapt to different load conditions.

[0024] Example 2 A V2G inverter control device comprises: a control unit, a protocol and interaction unit, a power inverter unit, a drive control unit, a built-in battery, and an auxiliary power supply, wherein the built-in battery is respectively connected to the protocol and interaction unit, the auxiliary power supply output side, the drive control unit, and the control unit via a switch; the control unit is connected to the drive control unit, the power inverter unit, and the protocol and interaction unit; the input side of the power inverter unit is connected to the DC bus of a charging gun, and the output side is connected to a load interface and the auxiliary power supply; the protocol and interaction unit is connected to a signal line of the charging gun.

[0025] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A V2G inverter control method, Features: The V2G inverter consists of a DC charging gun, a control unit, a protocol and interaction unit, a power inverter unit, a drive control unit, a built-in battery, and an auxiliary power supply. The control method is: The control unit collects the drive fault signal and outputs the SPWM control signal to the drive control unit; The drive control unit amplifies the SPWM control signal and outputs it to the power inverter unit; The power inverter unit converts the DC power of the vehicle's power battery into AC power to supply the load; The control unit collects the input voltage, output voltage and current signals of the power inverter unit for closed-loop calculation; The protocol and interaction unit displays the current status, fault information, input data, and output data; When the start switch is closed, the built-in battery supplies power to the protocol and interaction unit, the control unit, and the drive control unit. The protocol and interaction unit communicates with the vehicle BMS to close the PDU, allowing the power battery to output to the power inverter unit.

2. The V2G inverter control method according to claim 1, Features: The power inverter unit converts the DC power of the vehicle's power battery into 220V AC power.

3. The V2G inverter control method according to claim 1, Features: The protocol and interaction unit communicates with the cloud platform through the 4G module.

4. The V2G inverter control method according to claim 1, Features: The control unit stores dual closed-loop control parameters for loads with different characteristics.

5. The V2G inverter control method according to claim 4, Features: The dual closed-loop control parameters are divided into parameters for linear load, parameters when the power factor is greater than or equal to 0.8 and the load impedance is capacitive, parameters when the power factor is greater than or equal to 0.8 and the load impedance is inductive, parameters when the power factor is less than or equal to 0.8 and the load impedance is capacitive, parameters when the power factor is less than or equal to 0.8 and the load impedance is inductive, parameters when the temperature rise is less than or equal to 40°C, and parameters when the temperature rise is greater than or equal to 40°C.

6. The V2G inverter control method according to claim 4, Features: When powered on, the control unit loads the dual closed-loop control parameters and runs the dual closed-loop control, outputting the corresponding bipolar or unipolar double-frequency SPWM signal to the drive control unit, and the drive control unit controls the power inverter unit to output 50Hz, 220V single-phase AC mains.

7. The V2G inverter control method according to claim 6, Features: The input voltage, input current, output voltage, output current, overvoltage fault signal, overcurrent fault information, and overtemperature fault signal of the power inverter unit are collected. When the power inverter unit detects the output current, the DFT algorithm is run to calculate the harmonic content THD of the voltage waveform of N cycles. The phase difference is calculated based on the collected input voltage, input current, output voltage, and output current, and the power factor is calculated based on the phase difference.

8. The V2G inverter control method according to claim 4, Features: When switching the parameters in the dual closed-loop control parameters, the overshoot is less than 5% and the adjustment time is less than 5ms.

9. A V2G inverter control device, It is characterized in that include: Control unit, protocol and interaction unit, power inverter unit, drive control unit, built-in battery, auxiliary power supply, the built-in battery is connected to the protocol and interaction unit, the auxiliary power supply output side, the drive control unit and the control unit through a switch; the control unit is connected to the drive control unit, the power inverter unit, the protocol and interaction unit; the input side of the power inverter unit is connected to the DC bus of the charging gun, and the output side is connected to the load interface and the auxiliary power supply; the protocol and interaction unit is connected to the charging gun signal line.

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