CN102570560B - Charging-discharging system for V2G bilateral power conversion electric automobile and control method thereof - Google Patents

Abstract

The invention discloses a V2G bidirectional power conversion electric vehicle charging and discharging system and a control method thereof in the technical field of smart grids. The present invention adopts a single-phase or three-phase voltage-type PWM converter (VSC) as the first-stage power conversion circuit to realize energy conversion between the AC power grid and the first DC bus bar; adopts a symmetrical half-bridge LLC resonant bidirectional DC-DC The (DC/DC) converter is used as the second-level power conversion circuit to realize the energy conversion between the DC bus and the power battery pack. The beneficial effects of the present invention are: the current of the converter grid side of the primary power conversion circuit is close to a sine wave, and the harmonic content is small; the secondary power conversion circuit improves the conversion efficiency, dynamic performance and power density, and reduces the charging and discharging device of the electric vehicle The size and weight of the system can effectively improve the safety, reliability and economy of the system.

Description

V2G bidirectional power conversion electric vehicle charging and discharging system and its control method

technical field

The invention belongs to the technical field of smart grids, and in particular relates to a V2G bidirectional power conversion electric vehicle charging and discharging system and a control method thereof.

Background technique

With the smart level of the power grid and the sharp increase in the number of electric vehicles, a large number of electric vehicle batteries may become distributed energy storage units in the smart grid in the future. Statistics show that an electric vehicle is in the idle state 95% of the time, The electric vehicle battery can be charged by the grid during the non-peak load period of the grid, and the electric vehicle battery can provide electric energy to the grid during the peak load period of the grid to obtain the price difference. Between car owners and system dispatchers, this technology that realizes intelligent charging and discharging management through real-time electricity prices and smart meters is V2G (Vehicle to Grid) technology. The application of V2G technology can effectively adjust the peak-to-valley difference of the power grid, reduce the traditional peak-shaving backup power generation capacity, and improve the utilization efficiency of the power grid. Cars are converted according to the power of the main circuit of the electric vehicle charger. The total capacity of the electric vehicle charger is nearly 10 times that of the total installed capacity of wind power in China. If one-fifth of them, that is, 20 million vehicles are electric vehicles, their on-board batteries will It is enough to store the electric energy generated by all wind power plants in China. The huge energy storage efficiency of electric vehicles is equivalent to increasing the effective reserve capacity of the system, which will effectively stabilize the fluctuation of the output power of renewable energy generation and promote the acceptance of fluctuating renewable energy generation power by the grid. , to provide a new way to enhance the regulation ability of the power grid; and hundreds of electric vehicles can also form a micro-grid to operate, and can also be used as an emergency power supply in an emergency to provide effective support for the safe operation of the micro-grid.

The traditional charger uses silicon controlled rectifier bridge rectifier circuit to form the charging main circuit to realize the battery charging function, but the disadvantage is that the power conversion adopts the power frequency phase control method, which leads to serious distortion of the AC current waveform and large harmonic components; low power factor, And it is uncontrollable; moreover, the power frequency transformer is used to transform the voltage and electrically isolate it, resulting in large losses, resulting in low energy conversion efficiency of the whole machine, and a large amount of non-ferrous metal consumption, resulting in high cost.

Compared with the traditional thyristor rectifier phase control technology, PWM high-frequency inverter technology is a new power electronic conversion technology. Theoretical analysis and practical experience show that the volume and quality of electromagnetic devices (transformers, inductors and capacitors, etc.) are inversely proportional to the square root of the power supply frequency. The volume and quality of the device will drop to 5-10% of the power frequency design value. Therefore, high frequency enables power supply equipment to have the advantages of high efficiency, low noise, small size, good dynamic performance, and low cost, which is an inevitable development direction.

According to different working principles, DC/DC power conversion can be divided into topological forms such as forward, flyback, push-pull and bridge. The symmetrical flyback converter is very suitable for low power applications because of its simplest structure, low cost, and good transient response; the push-pull converter has a simple structure, but the switch tube needs to withstand twice the input voltage In addition, the peak value of the pulse voltage caused by the leakage inductance of the high-frequency transformer is added, so it is only suitable for the occasions where the working voltage of the converter is relatively low; the bridge DC/DC converter can achieve the required large transformation ratio, and can meet The application requirements of different power levels are suitable for medium and high power applications.

At present, PWM high-frequency full-bridge inverter technology has become the mainstream technology of electric vehicle chargers. Its main circuit is mainly composed of four parts: 1) Lightning protection and input filter circuit: its function is mainly to eliminate electromagnetic noise and clutter of the input power supply. The signal is suppressed to prevent interference with the power supply, and at the same time prevent the high-frequency clutter generated by the power supply itself from interfering with the power grid; 2) Primary rectification and filtering circuit: convert the AC voltage source into a DC pulsating voltage source, and become smoother after filtering The primary DC voltage source is used for the transformation of the next stage; 3) Inverter circuit: converts the rectified and filtered direct current into high-frequency alternating current, which is the core part of the high-frequency switching power supply. The higher the frequency, the larger the size and weight of the inverter transformer. The smaller the ratio to the output power; 4) Secondary rectification and filtering circuit: rectify and filter the high-frequency AC power again, and output stable and reliable DC voltage (or current) through voltage (or current) closed-loop control; through the battery management system communication management to meet the charging mode requirements of the vehicle battery under different working conditions.

However, further analysis of the circuit topology of electric vehicle chargers shows that ordinary electric vehicle chargers do not yet have the ability to feed power back to the grid.

Contents of the invention

The present invention discloses a V2G bidirectional power conversion electric vehicle charging and discharging system and a control method thereof aiming at the above defects. The main circuit of the present invention adopts a single-phase or three-phase voltage-type PWM converter (VSC) as the first-stage power conversion circuit to realize the energy conversion between the AC power grid and the first DC bus, referred to as "AC-DC (AC/DC) for short. DC) converter”; a symmetrical half-bridge LLC resonant bidirectional DC-DC (DC/DC) converter is used as the second-stage power conversion circuit to realize the energy conversion between the DC bus and the power battery pack, referred to as “bidirectional DC /DC Converter".

V2G bidirectional power conversion electric vehicle charging and discharging system includes single-phase V2G bidirectional power conversion electric vehicle charging and discharging system and three-phase V2G bidirectional power conversion electric vehicle charging and discharging system;

The structure of single-phase V2G bidirectional power conversion electric vehicle charging and discharging system is as follows: single-phase AC power supply, single-phase voltage-type PWM converter, first DC bus, symmetrical half-bridge LLC resonant bidirectional DC-DC converter and second DC busbar cascading;

The live wire of the single-phase AC power supply is connected to the connection of the upper and lower arms of one phase bridge arm through a linear inductor, the neutral line is directly connected to the connection of the upper and lower arms of the other phase bridge arm, and the C11 DC filter capacitor is connected in parallel to the positive pole of the first DC bus and the first 1 Between the negative poles of the DC bus, the C12 DC filter capacitor and the power battery pack are connected in parallel between the positive bus of the second DC bus and the negative bus of the second DC bus;

The structure of the three-phase V2G bidirectional power conversion electric vehicle charging and discharging system is as follows: three-phase AC power phase A, three-phase AC power phase B and three-phase AC power phase C are all connected to the corresponding phase bridge arm of the three-phase voltage-type PWM converter The midpoint of the three-phase voltage-type PWM converter, the first DC bus, the symmetrical half-bridge LLC resonant bidirectional DC-DC converter and the second DC bus are cascaded;

The live wire of phase A (Ua) of the three-phase AC power supply is connected to the connection of the upper and lower arms of the first bridge arm through the La linear inductor, and the live wire of phase B (Ub) of the three-phase AC power supply is connected to the upper and lower arms of the second bridge arm through the linear inductor of Lb. , the live wire of phase C (Uc) of the three-phase AC power supply is connected to the connection of the upper and lower arms of the third bridge arm through the Lc linear inductor; the C11 DC filter capacitor is connected in parallel between the positive pole of the first DC bus and the negative pole of the first DC bus , the C12 DC filter capacitor and the power battery pack are connected in parallel between the positive bus bar of the second DC bus bar and the negative bus bar of the second DC bus bar.

The structure of the single-phase voltage-type PWM converter is as follows: the upper arm and the lower arm are formed by using power switch tubes with anti-parallel diodes, and the upper and lower arms are connected in series to form a bridge arm; two bridge arms are connected in parallel to form a single-phase full bridge, A C11 DC filter capacitor is connected in parallel on the DC side;

The structure of the three-phase voltage-type PWM converter is as follows: the upper arm and the lower arm are formed by using power switch tubes with anti-parallel diodes, and the upper and lower arms are connected in series to form a bridge arm; three bridge arms are connected in parallel to form a three-phase bridge circuit , The DC side is connected in parallel with a C12 DC filter capacitor.

The power transmission of the symmetrical half-bridge LLC resonant bidirectional DC-DC converter is divided into forward power transmission and reverse power transmission; the symmetrical half-bridge LLC resonant bidirectional DC/DC converter consists of a switch network, a resonant network and The rectifier-load network is cascaded, with the T high-frequency transformer as the center, and the circuit on the left side is symmetrical to the circuit on the right side.

The symmetrical half-bridge LLC resonant bidirectional DC-DC converter realizes electrical isolation between the AC power supply system and the power battery pack through a T high-frequency transformer.

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the connection relationship of the switch network is as follows: the V5 switch tube of the anti-parallel VD5 fast recovery diode and the V6 switch tube of the anti-parallel VD6 fast recovery diode Connect in series, and then connect in parallel with C11 DC filter capacitor;

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the connection relationship of the resonant network is as follows: VD13 diode is connected in series with VD14 diode, VD9 diode is connected in series with VD10 diode, C1 split resonant capacitor is connected in series with C2 split The resonant capacitor, the above three are connected in parallel between the positive pole (S1+) of the first DC bus and the negative pole (S1-) of the first DC bus, one end of the L1 resonant inductor is connected to VD9 diode, VD10 diode, C1 split resonant capacitor and The common node of the C2 split resonant capacitor, the other end of which is connected to the common node of VD13 diode, VD14 diode and one end of the primary winding of the T high-frequency transformer; the other end of the primary winding of the T high-frequency transformer is connected to the public of the V5 switch tube and the V6 switch tube node;

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the connection relationship of the rectifier-load network is as follows: VD7 diode, VD8 diode, VD15 diode and VD16 diode form a single-phase full-bridge rectifier circuit, Then connect it in parallel with C12 DC filter capacitor.

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the VD13 diode and VD14 diode are connected in series to provide overvoltage protection for the L1 resonant inductor; the VD15 diode and VD16 diode are one of the single-phase full-bridge rectifiers. rectifier arm, and bypass L2 resonant inductor;

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs reverse power transmission, the VD15 diode and VD16 diode are connected in series to provide overvoltage protection for the L2 resonant inductor; the VD13 diode and VD14 diode are a single-phase full-bridge rectifier. arm, and bypass the L1 resonant inductor.

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the VD9 diode and the VD10 diode are connected in series to provide overvoltage protection for the C1 split resonant capacitor and the C2 split resonant capacitor; the VD11 diode and the VD12 diode Suppresses the LC resonance in the single-phase full-bridge rectifier circuit;

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs reverse power transmission, the VD11 diode and the VD12 diode are connected in series to provide overvoltage protection for the C3 split resonant capacitor and the C4 split resonant capacitor; the VD9 diode and the VD10 diode suppress LC resonance in a single-phase full-bridge rectifier circuit.

The C1 split resonant capacitor and the C2 split resonant capacitor are connected in series to form a split resonant capacitor topological structure, the root mean square current of the C1 split resonant capacitor and the C2 split resonant capacitor is half of a single resonant capacitor, and its capacitance is half of a single resonant capacitor;

The C3 split resonant capacitor and the C4 split resonant capacitor are connected in series to form a split resonant capacitor topological structure, the root mean square current of the C3 split resonant capacitor and the C4 split resonant capacitor is half of a single resonant capacitor, and its capacitance is half of a single resonant capacitor.

The control method of the V2G bidirectional power conversion electric vehicle charging and discharging system includes the control method of the single-phase V2G bidirectional power conversion electric vehicle charging and discharging system and the control method of the three-phase V2G bidirectional power conversion electric vehicle charging and discharging system;

A control method for a single-phase V2G bidirectional power conversion electric vehicle charging and discharging system includes the following steps:

1) Take the voltage signal from the live wire of the single-phase AC power supply, the voltage signal is synchronously tracked by the phase-locked loop, and the phase angle signal θ of the actual voltage signal is obtained, and the phase angle signal θ is sent to the space vector phase calculation module for calculation, and the value of sinθ is obtained and the values of cosθ, send the values of sinθ and cosθ to the αβ/dq converter and the dq/αβ converter respectively;

和i_q经第一加法器运算后形成误差信号，该误差信号经第一PI调节器得到q轴电压给定信号

将

输入到dq/αβ变换器中；2) Take the current signal from the live wire of the single-phase AC power supply, pass through the _iα - _iβ signal generating circuit and the αβ/dq converter to obtain the direct-axis signal component i _d and the quadrature-axis signal component i _q in the dq synchronous rotating coordinate system, and the q-axis Current given signal

and i _q form an error signal after being operated by the first adder, and the error signal is obtained by the first PI regulator to obtain the q-axis voltage given signal

Will

Input into the dq/αβ converter;

i_d和

通过第二加法器运算后形成误差信号，该误差信号经第二PI调节器比例、积分运算后得到d轴电压给定信号

dq/αβ变换器将同步旋转坐标系下的d轴电压给定信号

和q轴电压给定信号变换为αβ两相静止坐标系下

信号和

信号；3) The first DC voltage and current acquisition module acquires the first DC bus voltage u _dc1 , the first DC voltage and current acquisition module plays the role of electrical isolation and coefficient transformation, u _dc1 and the first DC bus voltage given value The error signal is formed by the third adder, and the error signal is input to the voltage regulator, and the d-axis current given signal is obtained after the proportional and integral operation of the voltage regulator

i _d and

The error signal is formed after the operation of the second adder, and the d-axis voltage given signal is obtained after the error signal is proportional and integrated by the second PI regulator

The dq/αβ converter will synchronously rotate the d-axis voltage given signal in the coordinate system

and q-axis voltage given signal Transformed into αβ two-phase stationary coordinate system

signal and

Signal;

信号和

信号变换为abc三相静止坐标系下

信号、信号和信号，再经PWM信号生成模块得到四路PWM调制信号；4) The αβ/abc converter further transforms the αβ two-phase stationary coordinate system into

signal and

The signal is transformed into the abc three-phase static coordinate system

Signal, signal and signal, and then get four PWM modulation signals through the PWM signal generation module;

通过第四加法器运算后得误差信号，该误差信号经第三PI调节器进行比例、积分调节后，得到第2直流母线的负极母线上的电流给定值

第2直流母线的负极母线上电流I_dc2和经第五加法器运算得误差信号，该误差信号经第四PI调节器进行比例、积分调节后，得到第2直流母线上的控制信号，将该控制信号输入至功率变换方向控制器的反向变换端；5) The first DC voltage and current acquisition module obtains the working current signal I _dc1 on the negative bus of the first DC bus, I _dc1 and the current given value on the negative bus of the first DC bus

The error signal is obtained after being calculated by the fourth adder. After the error signal is adjusted proportionally and integrally by the third PI regulator, the current given value on the negative bus of the second DC bus is obtained.

The current I _dc2 on the negative bus of the second DC bus and The error signal is calculated by the fifth adder, the error signal is adjusted proportionally and integrally by the fourth PI regulator, and the control signal on the second DC bus is obtained, and the control signal is input to the reverse direction of the power conversion direction controller transformation end;

通过第七加法器求得误差信号，将该误差信号输入至模式变换器的恒压模式端子，第2直流母线上的电流I_dc2和第2直流母线上的电流给定值

通过第八加法器求得误差信号，将该误差信号输入至模式变换器的恒流模式端子，模式变换器进行模式选择，经第五PI调节器进行比例、积分调节后，得到第1直流母线上的电流给定值

和第1直流母线上的工作电流I_dc1通过第六加法器求得误差信号，将该误差信号输入到功率变换方向控制器的正向变换端；6) The second DC bus voltage sensor is connected between the positive bus and the negative bus of the second DC bus to detect the voltage between the positive bus and the negative bus of the second DC bus; the second DC bus current sensor is connected to the second DC bus 2 DC bus negative bus, used to detect the current of the second DC bus, the above current and voltage are electrically isolated and coefficient transformed by the second DC voltage and current acquisition module, and the detection voltage U _dc2 of the second DC bus and the second Detection current I _dc2 on the DC bus, U _dc2 and the second DC bus voltage given signal

The error signal is obtained by the seventh adder, and the error signal is input to the constant voltage mode terminal of the mode converter, the current I _dc2 on the second DC bus and the current given value on the second DC bus

The error signal is obtained by the eighth adder, and the error signal is input to the constant current mode terminal of the mode converter, the mode converter performs mode selection, and after proportional and integral adjustment by the fifth PI regulator, the first DC bus is obtained Current given value on

and the operating current I _dc1 on the first DC bus to obtain an error signal through the sixth adder, and input the error signal to the forward conversion terminal of the power conversion direction controller;

7) The power conversion direction controller determines the forward and reverse conversion of power, and then converts the voltage to frequency through the voltage-frequency converter, and then forms the complementary signal of the upper and lower bridge arms with a 180° duty cycle through the driving signal generation module, and finally generates g1 driving signal, g2 driving signal, g3 driving signal and g4 driving signal;

The control method of the three-phase V2G bidirectional power conversion electric vehicle charging and discharging system includes the following steps:

1) Take the three-phase voltage signal and three-phase current signal from the live wire of phase A (Ua) of the three-phase AC power supply, the live wire of phase B (Ub) of the three-phase AC power supply and the live wire of phase C (Uc) of the three-phase AC power supply, and pass through 3/2 The converter realizes the transformation from the three-phase stationary coordinate system to the two-phase stationary coordinate system, and obtains u _α signal, u _β signal, i _α signal and i _β signal, and the u _α signal and u _β signal are calculated by the phase angle calculation module to obtain θ The sine function value sinθ, the cosine function value cosθ, send sinθ and cosθ to the dq/αβ converter;

和i_q经第一加法器运算后形成误差信号，该误差信号经第一PI调节器得到q轴电压给定信号

将输入到dq/αβ变换器中；2) The i _α signal and i _β signal are passed through the αβ/dq converter to obtain the direct axis signal component i _d and the quadrature axis signal component i _q in the dq synchronous rotating coordinate system, and the q axis current given signal

and i _q form an error signal after being operated by the first adder, and the error signal is obtained by the first PI regulator to obtain the q-axis voltage given signal

Will Input into the dq/αβ converter;

通过第三加法器形成误差信号，将误差信号输入至电压调节器中，经电压调节器比例、积分运算后得到d轴电流给定信号

i_d和

通过第二加法器运算后形成误差信号，该误差信号经第二PI调节器比例、积分运算后得到d轴电压给定信号

dq/αβ变换器将同步旋转坐标系下的d轴电压给定信号

和q轴电压给定信号变换为αβ两相静止坐标系下

信号和信号；3) The first DC voltage and current acquisition module acquires the first DC bus voltage u _dc1 , the first DC voltage and current acquisition module plays the role of electrical isolation and coefficient transformation, u _dc1 and the first DC bus voltage given value

The error signal is formed by the third adder, and the error signal is input to the voltage regulator, and the d-axis current given signal is obtained after the proportional and integral operation of the voltage regulator

i _d and

The error signal is formed after the operation of the second adder, and the d-axis voltage given signal is obtained after the error signal is proportional and integrated by the second PI regulator

The dq/αβ converter will synchronously rotate the d-axis voltage given signal in the coordinate system

and q-axis voltage given signal Transformed into αβ two-phase stationary coordinate system

signal and Signal;

信号和

信号变换为abc三相静止坐标系下

信号、

信号和

信号，再经PWM信号生成模块得到六路PWM调制信号；4) The αβ/abc converter further transforms the αβ two-phase stationary coordinate system into

signal and

The signal is transformed into the abc three-phase static coordinate system

Signal,

signal and

signal, and then get six channels of PWM modulation signals through the PWM signal generating module;

通过第四加法器运算后得误差信号，该误差信号经第三PI调节器进行比例、积分调节后，得到第2直流母线的负极母线上的电流给定值

第2直流母线的负极母线上电流I_dc2和

经第五加法器运算得误差信号，该误差信号经第四PI调节器进行比例、积分调节后，得到第2直流母线上的控制信号，将该控制信号输入至功率变换方向控制器的反向变换端；5) The first DC voltage and current acquisition module obtains the working current signal I _dc1 on the negative bus of the first DC bus, I _dc1 and the current given value on the negative bus of the first DC bus

The error signal is obtained after being calculated by the fourth adder. After the error signal is adjusted proportionally and integrally by the third PI regulator, the current given value on the negative bus of the second DC bus is obtained.

The current I _dc2 on the negative bus of the second DC bus and

The error signal is calculated by the fifth adder, the error signal is adjusted proportionally and integrally by the fourth PI regulator, and the control signal on the second DC bus is obtained, and the control signal is input to the reverse direction of the power conversion direction controller transformation end;

通过第七加法器求得误差信号，将该误差信号输入至模式变换器的恒压模式端子，第2直流母线上的电流I_dc2和第2直流母线上的电流给定值

通过第八加法器求得误差信号，将该误差信号输入至模式变换器的恒流模式端子，模式变换器进行模式选择，经第五PI调节器进行比例、积分调节后，得到第1直流母线上的电流给定值

和第1直流母线上的工作电流I_dc1通过第六加法器求得误差信号，将该误差信号输入到功率变换方向控制器的正向变换端；6) The second DC bus voltage sensor is connected between the positive bus and the negative bus of the second DC bus to detect the voltage between the positive bus and the negative bus of the second DC bus; the second DC bus current sensor is connected to the second DC bus 2 DC bus negative bus, used to detect the current of the second DC bus, the above current and voltage are electrically isolated and coefficient transformed by the second DC voltage and current acquisition module, and the detection voltage U _dc2 of the second DC bus and the second Detection current I _dc2 on the DC bus, U _dc2 and the second DC bus voltage given signal

The error signal is obtained by the seventh adder, and the error signal is input to the constant voltage mode terminal of the mode converter, the current I _dc2 on the second DC bus and the current given value on the second DC bus

The error signal is obtained by the eighth adder, and the error signal is input to the constant current mode terminal of the mode converter, the mode converter performs mode selection, and after proportional and integral adjustment by the fifth PI regulator, the first DC bus is obtained Current given value on

and the operating current I _dc1 on the first DC bus to obtain an error signal through the sixth adder, and input the error signal to the forward conversion terminal of the power conversion direction controller;

7) The power conversion direction controller determines the forward and reverse conversion of power, and then converts the voltage to frequency through the voltage-frequency converter, and then forms the complementary signal of the upper and lower bridge arms with a 180° duty cycle through the driving signal generation module, and finally generates g1 driving signal, g2 driving signal, g3 driving signal and g4 driving signal.

The beneficial effect of the present invention is that: on the basis of maintaining the DC bus voltage constant and automatically realizing the bidirectional energy regulation between the AC power grid and the DC bus, the primary power conversion circuit also realizes unit power factor (UPF) and sine wave AC current, Low harmonics (converter grid side current is close to sine wave, and the harmonic content is small); the secondary power conversion circuit adopts a symmetrical half-bridge LLC resonant bidirectional DC converter to improve conversion efficiency, dynamic performance and power density, and reduce the power consumption of electric vehicles. The volume and weight of the charging and discharging device, and the high-frequency inverter transformer completely isolates the electrical connection between the AC system and the power battery pack, effectively improving the safety, reliability and economy of the system.

Description of drawings

Figure 1 is a block diagram of V2G bidirectional power conversion electric vehicle charging and discharging system;

Figure 2 is the topology of the single-phase charging and discharging main circuit;

Figure 3 is the topology of the three-phase charging and discharging main circuit;

4 is a block diagram of a topology control method for a single-phase charging and discharging main circuit;

5 is a block diagram of a topology control method for a three-phase charging and discharging main circuit;

Figure 6 is the basic circuit of the forward transmission of the symmetrical half-bridge LLC resonant bidirectional DC converter.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in FIG. 1 , the present invention discloses a V2G bidirectional power conversion electric vehicle charging and discharging system and a control method thereof. The main circuit adopts single-phase or three-phase voltage type PWM converter (VSC) as the first-level power conversion circuit to realize the connection between the AC power grid and the first DC bus (by the positive bus S1+ of the first DC bus and the negative bus of the first DC bus). The energy conversion between S1-composition) is referred to as "AC/DC converter" for short; the symmetrical half-bridge LLC resonant bidirectional DC-DC converter is used as the secondary power conversion circuit to realize the connection between the DC bus and the EV power battery pack. The energy conversion is referred to as "DC/DC converter" for short; the AC/DC converter and DC/DC converter are connected in parallel through the first DC bus. The V2G bidirectional power conversion electric vehicle charging and discharging system realizes the acquisition of AC side voltage and current, the SVPWM double closed-loop control of the AC/DC converter, the bidirectional closed-loop control and bidirectional conversion control of the DC/DC converter, and the voltage of the EV power battery pack , current and other battery charging and discharging information collection.

As shown in Figure 2, the structure of the single-phase V2G bidirectional power conversion electric vehicle charging and discharging system is as follows: single-phase AC power supply U, single-phase voltage-type PWM converter, the first DC bus (from the positive bus S1+ of the first DC bus and the negative bus S1- of the first DC bus, the symmetrical half-bridge LLC resonant bidirectional DC-DC converter and the second DC bus (composed of the positive bus S2+ of the second DC bus and the negative bus S2- of the second DC bus composition) cascade;

The live wire U of the single-phase AC power supply is connected to the connection of the upper and lower arms of one phase bridge arm through the linear inductor L, the neutral line is directly connected to the connection of the upper and lower arms of the other phase bridge arm, and the C11 DC filter capacitor is connected in parallel to the positive pole of the first DC bus Between S1+ and the negative pole S1- of the first DC bus, the C12 DC filter capacitor and the power battery pack are connected in parallel between the positive bus S2+ of the second DC bus and the negative bus S2- of the second DC bus;

The structure of the single-phase voltage-type PWM converter is as follows: V1 power switch tube and VD1 anti-parallel diode constitute the first upper arm, V2 power switch tube and VD2 anti-parallel diode constitute the first lower arm, V3 power switch tube and VD3 anti-parallel diode The second upper arm is formed, the V4 power switch tube and the VD4 anti-parallel diode form the second lower arm; the first upper arm and the first lower arm are connected in series to form the first bridge arm, and the second upper arm and the second lower arm are connected in series to form the second bridge arm. The two bridge arms are connected in parallel to form a single-phase full bridge; the DC side is connected in parallel with a C11 DC filter capacitor, the live wire of the single-phase AC power supply U is connected to the connection of the upper and lower arms of the first bridge arm through a linear inductor L, and the neutral line is directly connected to the connection of the second bridge arm The junction of the upper and lower arms.

As shown in Figure 3, the structure of the three-phase V2G bidirectional power conversion electric vehicle charging and discharging system is as follows: the three-phase AC power A phase Ua, the three-phase AC power B phase Ub and the three-phase AC power C phase Uc are all connected to the three-phase voltage Type PWM converter corresponds to the midpoint of the phase bridge arm, three-phase voltage type PWM converter, the first DC bus (composed of the positive bus S1+ of the first DC bus and the negative bus S1- of the first DC bus), symmetrical The half-bridge LLC resonant bidirectional DC-DC converter is cascaded with the second DC bus (composed of the positive bus S2+ of the second DC bus and the negative bus S2- of the second DC bus);

Three-phase AC power supply A phase Ua live wire is connected to the connection of the upper and lower arms of the first bridge arm through the La linear inductor, and the B-phase Ub live wire of the three-phase AC power supply is connected to the connection of the upper and lower arms of the second bridge arm through the Lb linear inductor. Three-phase The C-phase Uc live wire of the AC power supply is connected to the connection of the upper and lower arms of the third bridge arm through the Lc linear inductor; the C11 DC filter capacitor is connected in parallel between the positive pole S1+ of the first DC bus and the negative pole S1- of the first DC bus, and the C12 DC Both the filter capacitor and the power battery pack are connected in parallel between the positive bus S2+ of the second DC bus and the negative bus S2- of the second DC bus.

The structure of the three-phase voltage-type PWM converter is as follows: V17 power switch tube and VD17 anti-parallel diode form the first upper arm, V18 rate switch tube and VD18 anti-parallel diode form the first lower arm, V19 power switch tube and VD19 anti-parallel diode Constitute the second upper arm, V20 power switch tube and VD20 anti-parallel diode form the second lower arm, V21 power switch tube and VD21 anti-parallel diode form the third upper arm, V22 power switch tube and VD22 anti-parallel diode form the third lower arm, the first One upper arm and the first lower arm are connected in series to form the first bridge arm, the second upper arm and the second lower arm are connected in series to form the second bridge arm, the third upper arm and the third lower arm are connected in series to form the third bridge arm, and the three bridge arms are connected in parallel. Three-phase bridge circuit; C11 DC filter capacitor connected in parallel on the DC side, the live wire of the first three-phase AC power supply Ua is connected to the connection of the upper and lower arms of the first bridge arm through the linear inductor La, and the live wire of the second three-phase AC power supply Ub is connected through the linear inductor Lb It is connected to the joint of the upper and lower arms of the second bridge arm, and the live wire of the third three-phase AC power supply Uc is connected to the joint of the upper and lower arms of the third bridge arm through the Lc linear inductance, and the neutral point is N.

The power transmission of the symmetrical half-bridge LLC resonant bidirectional DC-DC converter is divided into forward power transmission and reverse power transmission. It is assumed that the forward power transmission of the converter is from port 1-1′ to port 2- The transmission in the direction of 2', the reverse power transmission of the converter is the transmission of power from port 2-2' to port 1-1'. The symmetrical half-bridge LLC resonant bidirectional DC/DC converter is composed of a switch network, a resonant network and a rectifier-load network in series. The T high-frequency transformer is the center, and the left circuit and the right circuit have a symmetrical structure. The T high-frequency transformer The transformation ratio is 1:1.

The symmetrical half-bridge LLC resonant bidirectional DC-DC converter realizes the electrical isolation of the AC power supply system (referring to single-phase AC power supply or three-phase AC power supply) and the power battery pack through a T high-frequency transformer.

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the connection relationship of the switch network is as follows: the V5 switch tube of the anti-parallel VD5 fast recovery diode is connected in series with the V6 switch tube of the anti-parallel VD6 fast recovery diode, Then connect it in parallel with C11 DC filter capacitor;

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the connection relationship of the resonant network is as follows: VD13 diode is connected in series with VD14 diode, VD9 diode is connected in series with VD10 diode, C1 split resonant capacitor is connected in series with C2 split resonant capacitor , the above three are connected in parallel between the positive pole (S1+) of the first DC bus and the negative pole (S1-) of the first DC bus, and one end of the L1 resonant inductor is connected to the VD9 diode, VD10 diode, C1 split resonant capacitor and C2 split The common node of the body resonant capacitor, the other end of which is connected to the common node of VD13 diode, VD14 diode and one end of the primary winding of the T high frequency transformer; the other end of the primary winding of the T high frequency transformer is connected to the common node of the V5 switch tube and the V6 switch tube;

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the connection relationship of the rectifier-load network is as follows: VD7 diode, VD8 diode, VD15 diode and VD16 diode form a single-phase full-bridge rectifier circuit, and then connect with C12 DC filter capacitor is connected in parallel.

When the switching network and resonant network on one side of the high-frequency transformer work, the switching network and resonant network on the other side automatically evolve into a rectifier-load network, and the networks on both sides together form a complete LLC resonant converter to achieve power in this direction. Transformation; due to the complete symmetry of the structure, the reverse is also established. When the reverse transformation is performed, the topology structure will be automatically reconfigured to form a reverse LLC resonant converter to achieve reverse power conversion.

At the same time, when the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, the VD13 diode and VD14 diode are connected in series to provide overvoltage protection for the L1 resonant inductor; the VD15 diode and VD16 diode are a rectifier of the single-phase full-bridge rectifier arm, and bypass the L2 resonant inductor; when the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs reverse power transmission, the VD15 diode and VD16 diode are connected in series to provide overvoltage protection for the L2 resonant inductor; the VD13 diode and VD14 diode are single One leg of a full-bridge rectifier and bypass the L1 resonant inductor.

In general, on one side of the T high-frequency transformer, diodes can be used as simple and cheap overvoltage protection of the resonant inductor in the resonant network; while on the other side, symmetrically positioned diodes automatically convert to A rectifier arm, and separate the unused resonant inductance on the same side from the main circuit to avoid a large internal impedance drop in the output side circuit, so that the relevant diodes have clamp protection, rectification and automatic separation of the output circuit Composite functions such as internal impedance.

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs forward power transmission, VD9 diode and VD10 diode are connected in series to provide overvoltage protection for C1 split resonant capacitor and C2 split resonant capacitor; VD11 diode and VD12 diode suppress single LC resonance in phase full bridge rectifier circuit;

When the symmetrical half-bridge LLC resonant bidirectional DC-DC converter performs reverse power transmission, VD11 diode and VD12 diode are connected in series to provide overvoltage protection for C3 split resonant capacitor and C4 split resonant capacitor; VD9 diode and VD10 diode suppress single-phase LC resonance in full bridge rectifier loop.

The C1 split resonant capacitor and the C2 split resonant capacitor are connected in series to form a split resonant capacitor topology structure. The root mean square current of the C1 split resonant capacitor and the C2 split resonant capacitor is half of a single resonant capacitor, and its capacitance is a single resonant capacitor. half of the capacitance;

The C3 split resonant capacitor and the C4 split resonant capacitor are connected in series to form a split resonant capacitor topology. The root mean square current of the C3 split resonant capacitor and the C4 split resonant capacitor is half of a single resonant capacitor, and its capacitance is a single resonant capacitor. half of the capacitance.

Figure 6 shows the basic circuit of the symmetrical half-bridge LLC resonant bidirectional DC/DC converter for forward power transmission. At this time, the T high-frequency transformer is equivalent to the L _m primary excitation inductance and the ideal high-frequency transformer It consists of a switch network, a resonant network, and a rectifier-load network in series.

The connection relationship of the switch network is as follows: the V5 switch tube of the anti-parallel VD5 fast recovery diode is connected in series with the V6 switch tube of the anti-parallel VD6 fast recovery diode, and then connected in parallel with the C11 DC filter capacitor.

The connection relationship of the resonant network is as follows: the C1 split resonant capacitor is connected in series with the C2 split resonant capacitor, one end of the L1 resonant inductor is connected to the common node of the C1 split resonant capacitor and the C2 split resonant capacitor, and the other end is connected to the Lm primary excitation inductance; The excitation inductance on the primary side of Lm is connected to the common node of the V5 switch tube and the V6 switch tube, and the excitation inductance on the primary side of Lm is connected in parallel with the ideal transformer. The resonant network is mainly equivalent to a voltage divider, and its impedance varies with the operating frequency.

On the secondary side of the T high-frequency transformer, the connection relationship between the rectifier and the load network is as follows: VD7 diode and VD8 one-pole tube are connected in series to form a rectifier arm, and one end of the high-frequency transformer secondary winding is connected between them; VD15 diode and VD16 diode Another rectifier arm is formed in series, and the other end of the secondary winding of the high-frequency transformer is connected between the two; the two rectifier arms are connected with a common cathode and a common anode, and then connected in parallel with a C12 current filter capacitor.

The control method of the V2G bidirectional power conversion electric vehicle charging and discharging system includes the control method of the single-phase V2G bidirectional power conversion electric vehicle charging and discharging system and the control method of the three-phase V2G bidirectional power conversion electric vehicle charging and discharging system; as shown in Figure 4, the single A control method for a phase V2G bidirectional power conversion electric vehicle charging and discharging system includes the following steps:

1) Take the voltage signal from the live wire of the single-phase AC power supply U, and the voltage signal is synchronously tracked by the phase-locked loop (PLL) 1 to obtain the phase angle signal θ of the actual voltage signal, and send the phase angle signal θ to the space vector phase calculation module 2 for calculation Calculate, obtain the numerical value of sinθ and the numerical value of cosθ, send the numerical value of sinθ and the numerical value of cosθ to αβ/dq converter 4 and dq/αβ converter 11 respectively;

和i_q经第一加法器6运算后形成误差信号，该误差信号经第一PI(比例-积分)调节器8得到q轴电压给定信号

将输入到dq/αβ变换器11中；2) Take the current signal from the live wire of the single-phase AC power supply U, pass through the _iα - _iβ signal generation circuit 3 and the αβ/dq converter 4 to obtain the direct axis signal component i _d and the quadrature axis signal component i _q in the dq synchronous rotating coordinate system , q-axis current given signal

and i _q form an error signal after being operated by the first adder 6, and the error signal is obtained by the first PI (proportional-integral) regulator 8 to obtain the q-axis voltage given signal

Will Input into the dq/αβ converter 11;

通过第三加法器14形成误差信号，将误差信号输入至电压调节器13中，经电压调节器13比例、积分运算后得到d轴电流给定信号

i_d和

通过第二加法器7运算后形成误差信号，该误差信号经第二PI调节器9比例、积分运算后得到d轴电压给定信号

dq/αβ变换器11将同步旋转坐标系下的d轴电压给定信号

和q轴电压给定信号

变换为αβ两相静止坐标系下

信号和

信号；3) The first DC voltage and current acquisition module 12 acquires the first DC bus voltage u _dc1 (the voltage at both ends of the C11 DC filter capacitor), the first DC voltage and current acquisition module 12 plays the role of electrical isolation and coefficient conversion, u _dc1 and the second 1 DC bus voltage given value

The error signal is formed by the third adder 14, and the error signal is input to the voltage regulator 13, and the d-axis current given signal is obtained after the proportional and integral operation of the voltage regulator 13

i _d and

The error signal is formed after the operation of the second adder 7, and the d-axis voltage given signal is obtained after the error signal is proportional and integrated by the second PI regulator 9

The dq/αβ converter 11 will give the d-axis voltage signal under the synchronous rotating coordinate system

and q-axis voltage given signal

Transformed into αβ two-phase stationary coordinate system

signal and

Signal;

信号变换为abc三相静止坐标系下

信号、

信号和

信号，再经PWM信号生成模块5得到四路PWM调制信号；4) The αβ/abc converter 10 further transforms the αβ two-phase stationary coordinate system into signal and

The signal is transformed into the abc three-phase static coordinate system

Signal,

signal and

signal, and then through the PWM signal generating module 5 to obtain four PWM modulation signals;

第2直流母线的负极母线S2-上电流I_dc2和经第五加法器17运算得误差信号，该误差信号经第四PI调节器18进行比例、积分调节后(实现了反向变换控制)，得到第2直流母线上的控制信号，将该控制信号输入至功率变换方向控制器21的反向变换端；5) The first DC bus current sensor is connected to the negative bus S1- of the first DC bus, which is located below the intersection of the first DC bus and the DC filter capacitor C11, and plays the role of sensing the DC current signal. The first DC voltage and current The acquisition module 12 obtains the working current signal I _dc1 on the negative bus S1- of the first DC bus, _Idc1 and the current given value on the negative bus S1- of the first DC bus The error signal is obtained after calculation by the fourth adder 15, and after the error signal is adjusted proportionally and integrally by the third PI regulator 16, the current given value on the negative bus S2- of the second DC bus is obtained

The current I _dc2 on the negative bus S2- of the second DC bus and After the fifth adder 17 calculates the error signal, the error signal is adjusted proportionally and integrally by the fourth PI regulator 18 (reverse conversion control is realized), and the control signal on the second DC bus is obtained, and the control signal Input to the inverse conversion terminal of the power conversion direction controller 21;

通过第八加法器26求得误差信号，将该误差信号输入至模式变换器24的恒流模式端子，模式变换器24进行模式选择，经第五PI调节器23进行比例、积分调节后，得到第1直流母线上的电流给定值

和第1直流母线上的工作电流I_dc1通过第六加法器22求得误差信号(实现了正向变换控制)，将该误差信号输入到功率变换方向控制器21的正向变换端；6) The second DC bus voltage sensor is connected between the positive bus S2+ and the negative bus S2- of the second DC bus to detect the voltage between the positive bus S2+ and the negative bus S2- of the second DC bus; the second DC The bus current sensor is connected to the negative bus S2- of the second DC bus, and is used to detect the current of the second DC bus. The detection voltage U _dc2 of the bus and the detection current I _dc2 on the second DC bus, U _dc2 and the given signal of the voltage of the second DC bus The error signal is obtained by the seventh adder 25, and the error signal is input to the constant voltage mode terminal of the mode converter 24, the current I _dc2 on the second DC bus and the current given value on the second DC bus

The error signal is obtained by the eighth adder 26, the error signal is input to the constant current mode terminal of the mode converter 24, the mode converter 24 performs mode selection, and after the fifth PI regulator 23 performs proportional and integral adjustments, the obtained Current given value on the 1st DC bus

and the operating current I _dc1 on the 1st DC bus to obtain the error signal (realized the forward conversion control) by the sixth adder 22, and the error signal is input to the forward conversion terminal of the power conversion direction controller 21;

7) The power conversion direction controller 21 determines the forward and reverse conversion of power, and then the voltage-to-frequency conversion is performed through the voltage-frequency converter 20, and then the driving signal generation module 19 forms complementary signals of the upper and lower bridge arms with a duty ratio of 180° , and finally generate the g1 driving signal, g2 driving signal, g3 driving signal and g4 driving signal, and the g1 driving signal, g2 driving signal, g3 driving signal and g4 driving signal are respectively used to drive the V5 switching tube, V6 switching tube, V8 switching tube and V7 switch tube;

As shown in Figure 5, the control method of the three-phase V2G bidirectional power conversion electric vehicle charging and discharging system includes the following steps:

1) Take the three-phase voltage signal and the three-phase current signal from the A-phase Ua live wire of the three-phase AC power supply, the B-phase Ub live wire of the three-phase AC power supply, and the C-phase Uc live wire of the three-phase AC power supply, and realize the three-phase through the 3/2 converter 31 The transformation from the stationary coordinate system to the two-phase stationary coordinate system can obtain u _α signal, u _β signal, i _α signal and i _β signal, and the u _α signal and u _β signal can be calculated by the phase angle calculation module 32 to obtain the sine function value of θ sinθ, cosine function value cosθ, send sinθ and cosθ to dq/αβ converter 11;

将

输入到dq/αβ变换器11中；2) The i _α signal and i _β signal pass through the αβ/dq converter 4 to obtain the direct axis signal component i _d and the quadrature axis signal component i _q in the dq synchronous rotating coordinate system, and the q axis current given signal and i _q form an error signal after being operated by the first adder 6, and the error signal is obtained by the first PI (proportional-integral) regulator 8 to obtain the q-axis voltage given signal

Will

Input into the dq/αβ converter 11;

通过第三加法器14形成误差信号，将误差信号输入至电压调节器13中，经电压调节器13比例、积分运算后得到d轴电流给定信号

i_d和

通过第二加法器7运算后形成误差信号，该误差信号经第二PI调节器9比例、积分运算后得到d轴电压给定信号

dq/αβ变换器11将同步旋转坐标系下的d轴电压给定信号

和q轴电压给定信号

变换为αβ两相静止坐标系下信号和

信号；3) The first DC voltage and current acquisition module 12 acquires the first DC bus voltage u _dc1 (the voltage at both ends of the C11 DC filter capacitor), the first DC voltage and current acquisition module 12 plays the role of electrical isolation and coefficient conversion, u _dc1 and the second 1 DC bus voltage given value

The error signal is formed by the third adder 14, and the error signal is input to the voltage regulator 13, and the d-axis current given signal is obtained after the proportional and integral operation of the voltage regulator 13

i _d and

The error signal is formed after the operation of the second adder 7, and the d-axis voltage given signal is obtained after the error signal is proportional and integrated by the second PI regulator 9

The dq/αβ converter 11 will give the d-axis voltage signal under the synchronous rotating coordinate system

and q-axis voltage given signal

Transformed into αβ two-phase stationary coordinate system signal and

Signal;

信号和信号变换为abc三相静止坐标系下

信号、

信号和

信号，再经PWM信号生成模块5得到六路PWM调制信号；4) The αβ/abc converter 10 further transforms the αβ two-phase stationary coordinate system into

signal and The signal is transformed into the abc three-phase static coordinate system

Signal,

signal and

signal, and then obtain six channels of PWM modulation signals through the PWM signal generation module 5;

通过第四加法器15运算后得误差信号，该误差信号经第三PI调节器16进行比例、积分调节后，得到第2直流母线的负极母线S2-上的电流给定值

第2直流母线的负极母线S2-上电流I_dc2和

经第五加法器17运算得误差信号，该误差信号经第四PI调节器18进行比例、积分调节后(实现了反向变换控制)，得到第2直流母线上的控制信号，将该控制信号输入至功率变换方向控制器21的反向变换端；5) The first DC bus current sensor is connected to the negative bus S1- of the first DC bus, which is located below the intersection of the first DC bus and the DC filter capacitor C11, and plays the role of sensing the DC current signal. The first DC voltage and current The acquisition module 12 obtains the working current signal I _dc1 on the negative bus S1- of the first DC bus, _Idc1 and the current given value on the negative bus S1- of the first DC bus

The error signal is obtained after calculation by the fourth adder 15, and after the error signal is adjusted proportionally and integrally by the third PI regulator 16, the current given value on the negative bus S2- of the second DC bus is obtained

The current I _dc2 on the negative bus S2- of the second DC bus and

After the fifth adder 17 calculates the error signal, the error signal is adjusted proportionally and integrally by the fourth PI regulator 18 (reverse conversion control is realized), and the control signal on the second DC bus is obtained, and the control signal Input to the inverse conversion terminal of the power conversion direction controller 21;

通过第七加法器25求得误差信号，将该误差信号输入至模式变换器24的恒压模式端子，第2直流母线上的电流I_dc2和第2直流母线上的电流给定值

通过第八加法器26求得误差信号，将该误差信号输入至模式变换器24的恒流模式端子，模式变换器24进行模式选择，经第五PI调节器23进行比例、积分调节后，得到第1直流母线上的电流给定值

和第1直流母线上的工作电流I_dc1通过第六加法器22求得误差信号(实现了正向变换控制)，将该误差信号输入到功率变换方向控制器21的正向变换端；6) The second DC bus voltage sensor is connected between the positive bus S2+ and the negative bus S2- of the second DC bus to detect the voltage between the positive bus S2+ and the negative bus S2- of the second DC bus; the second DC The bus current sensor is connected to the negative bus S2- of the second DC bus, and is used to detect the current of the second DC bus. The detection voltage U _dc2 of the bus and the detection current I _dc2 on the second DC bus, U _dc2 and the given signal of the voltage of the second DC bus

The error signal is obtained by the seventh adder 25, and the error signal is input to the constant voltage mode terminal of the mode converter 24, the current I _dc2 on the second DC bus and the current given value on the second DC bus

The error signal is obtained by the eighth adder 26, the error signal is input to the constant current mode terminal of the mode converter 24, the mode converter 24 performs mode selection, and after the fifth PI regulator 23 performs proportional and integral adjustments, the obtained Current given value on the 1st DC bus

and the operating current I _dc1 on the 1st DC bus to obtain the error signal (realized the forward conversion control) by the sixth adder 22, and the error signal is input to the forward conversion terminal of the power conversion direction controller 21;

7) The power conversion direction controller 21 determines the forward and reverse conversion of power, and then the voltage-to-frequency conversion is performed through the voltage-frequency converter 20, and then the driving signal generation module 19 forms complementary signals of the upper and lower bridge arms with a duty ratio of 180° , and finally generate the g1 driving signal, g2 driving signal, g3 driving signal and g4 driving signal, and the g1 driving signal, g2 driving signal, g3 driving signal and g4 driving signal are respectively used to drive the V5 switching tube, V6 switching tube, V8 switching tube and V7 switch tube.

Claims (1)

1. the control method of a V2G bi-directional power conversion electric automobile charge-discharge system, V2G bi-directional power conversion electric automobile charge-discharge system comprises single-phase V2G bi-directional power conversion electric automobile charge-discharge system and three-phase V2G bi-directional power conversion electric automobile charge-discharge system, wherein single-phase V2G bi-directional power conversion electric automobile charge-discharge system is made up of single-phase electricity die mould pwm converter and symmetrical half-bridge LLC resonant bidirectional DC-DC converter cascade, wherein three-phase V2G bi-directional power conversion electric automobile charge-discharge system is made up of three-phase voltage type pwm converter and symmetrical half-bridge LLC resonant bidirectional DC-DC converter cascade,

It is characterized in that, the control method of V2G bi-directional power conversion electric automobile charge-discharge system comprises the control method of single-phase V2G bi-directional power conversion electric automobile charge-discharge system and the control method of three-phase V2G bi-directional power conversion electric automobile charge-discharge system;

The concrete steps of the control method of described single-phase V2G bi-directional power conversion electric automobile charge-discharge system are:

1) press signal from single phase alternating current power supply (U) live wire power getting, voltage signal is synchronously followed the tracks of through phase-locked loop (1), obtain the phase angle signal θ of actual voltage signal, phase angle signal θ is delivered to space vector phase calculation module (2) to be calculated, obtain the numerical value of sin θ and the numerical value of cos θ, the numerical value of the numerical value of sin θ and cos θ is delivered to respectively to α β/dq converter (4) and dq/ α β converter (11);

2) flow signal through i from single phase alternating current power supply (U) live wire power getting _α-i _βsignal generating circuit (3) and α β/dq converter (4) obtain the d-axis signal component i under dq synchronous rotating frame _dwith quadrature axis signal component i _q, the given signal of q shaft current

and i _qafter first adder (6) computing, form error signal, this error signal obtains the given signal of q shaft voltage through the first pi regulator (8)

will

be input in dq/ α β converter (11);

3) the first DC voltage and current acquisition module (12) gathers the 1st DC bus-bar voltage u _dc1, the first DC voltage and current acquisition module (12) plays the effect of electrical isolation and transformation of coefficient, u _dc1with the 1st DC bus-bar voltage set-point

form error signal by the 3rd adder (14), error signal is inputed in voltage regulator (13), after voltage regulator (13) ratio, integral operation, obtain the given signal of d shaft current i _dwith

by forming error signal after second adder (7) computing, this error signal obtains the given signal of d shaft voltage after the second pi regulator (9) ratio, integral operation

dq/ α β converter (11) is by the given signal of d shaft voltage under synchronous rotating frame with the given signal of q shaft voltage

be transformed under α β two-phase rest frame

signal and

signal;

4) α β/abc converter (10) is further by under α β two-phase rest frame

signal and signal is transformed under abc three phase static coordinate system

signal,

signal and

signal, then obtain four road PWM modulation signals through pwm signal generation module (5);

5) the first DC voltage and current acquisition module (12) obtains the operating current signal I on the negative pole bus (S1-) of the 1st DC bus _dc1, I _dc1with the given value of current value on the negative pole bus (S1-) of the 1st DC bus

by after the 4th adder (15) computing error signal, this error signal is carried out after ratio, integral adjustment through the 3rd pi regulator (16), obtains the given value of current value on the negative pole bus (S2-) of the 2nd DC bus

the upper electric current I of negative pole bus (S2-) of the 2nd DC bus _dc2with

obtain error signal through slender acanthopanax musical instruments used in a Buddhist or Taoist mass (17) computing, this error signal is carried out after ratio, integral adjustment through the 4th pi regulator (18), obtain the control signal on the 2nd DC bus, this control signal is inputed to the reciprocal transformation end of power conversion direction controller (21);

6) the 2nd DC bus-bar voltage transducer is connected between the positive electrode bus (S2+) and negative pole bus (S2-) of the 2nd DC bus, for detection of the voltage between positive electrode bus (S2+) and the negative pole bus (S2-) of the 2nd DC bus; The 2nd DC bus current transducer is connected on the 2nd DC bus negative pole bus (S2-), for detection of the electric current of the 2nd DC bus, above-mentioned electric current and voltage carry out after electrical isolation and transformation of coefficient through the second DC voltage and current acquisition module (27), obtain the detection voltage U of the 2nd DC bus _dc2with the detection electric current I on the 2nd DC bus _dc2, U _dc2with the given signal of the 2nd DC bus-bar voltage

try to achieve error signal by the 7th adder (25), this error signal is inputed to the constant voltage mode terminal of mode converter (24), the electric current I on the 2nd DC bus _dc2with the given value of current value on the 2nd DC bus try to achieve error signal by the 8th adder (26), this error signal is inputed to the constant current mode terminal of mode converter (24), mode converter (24) carries out model selection, carry out after ratio, integral adjustment through the 5th pi regulator (23), obtain the given value of current value on the 1st DC bus

with the operating current I on the 1st DC bus _dc1try to achieve error signal by the 6th adder (22), this error signal is input to the positive-going transition end of power conversion direction controller (21);

7) power conversion direction controller (21) is determined forward and reverse conversion of power, carry out the conversion of voltage to frequency through Voltage-to-frequency Converter (20) again, by driving signal generation module (19) to form the upper and lower bridge arm complementary signal with 180 ° of duty ratios, finally generate g1 and drive signal, g2 to drive signal, g3 to drive signal and g4 to drive signal;

The concrete steps of the control method of described three-phase V2G bi-directional power conversion electric automobile charge-discharge system are:

1) get three-phase voltage signal and three-phase current signal from three-phase alternating-current supply A phase (Ua) live wire, three-phase alternating-current supply B phase (Ub) live wire and three-phase alternating-current supply C phase (Uc) live wire, realize three phase static coordinate and be tied to the conversion of two-phase rest frame through 3/2 converter (31), obtain u _αsignal, u _βsignal, i _αsignal and i _βsignal, u _αsignal and u _βsine function sin θ, cosine function value cos θ that signal obtains θ after phase calculation module (32) is calculated, deliver to sin θ and cos θ in dq/ α β converter (11);

2) i _αsignal and i _βsignal obtains the d-axis signal component i under dq synchronous rotating frame through α β/dq converter (4) _dwith quadrature axis signal component i _q, the given signal of q shaft current and i _qafter first adder (6) computing, form error signal, this error signal obtains the given signal of q shaft voltage through the first pi regulator (8)

will

be input in dq/ α β converter (11);

3) the first DC voltage and current acquisition module (12) gathers the 1st DC bus-bar voltage u _dc1, the first DC voltage and current acquisition module (12) plays the effect of electrical isolation and transformation of coefficient, u _dc1with the 1st DC bus-bar voltage set-point

form error signal by the 3rd adder (14), error signal is inputed in voltage regulator (13), after voltage regulator (13) ratio, integral operation, obtain the given signal of d shaft current i _dwith

by forming error signal after second adder (7) computing, this error signal obtains the given signal of d shaft voltage after the second pi regulator (9) ratio, integral operation

dq/ α β converter (11) is by the given signal of d shaft voltage under synchronous rotating frame

with the given signal of q shaft voltage

be transformed under α β two-phase rest frame

signal and

signal;

4) α β/abc converter (10) is further by under α β two-phase rest frame

signal and

signal is transformed under abc three phase static coordinate system

signal,

signal and

signal, then obtain six road PWM modulation signals through pwm signal generation module (5);

5) the first DC voltage and current acquisition module (12) obtains the operating current signal I on the negative pole bus (S1-) of the 1st DC bus _dc1, I _dc1with the given value of current value on the negative pole bus (S1-) of the 1st DC bus

by after the 4th adder (15) computing error signal, this error signal is carried out after ratio, integral adjustment through the 3rd pi regulator (16), obtains the given value of current value on the negative pole bus (S2-) of the 2nd DC bus the upper electric current I of negative pole bus (S2-) of the 2nd DC bus _dc2with obtain error signal through slender acanthopanax musical instruments used in a Buddhist or Taoist mass (17) computing, this error signal is carried out after ratio, integral adjustment through the 4th pi regulator (18), obtain the control signal on the 2nd DC bus, this control signal is inputed to the reciprocal transformation end of power conversion direction controller (21);

6) the 2nd DC bus-bar voltage transducer is connected between the positive electrode bus (S2+) and negative pole bus (S2-) of the 2nd DC bus, for detection of the voltage between positive electrode bus (S2+) and the negative pole bus (S2-) of the 2nd DC bus; The 2nd DC bus current transducer is connected on the 2nd DC bus negative pole bus (S2-), for detection of the electric current of the 2nd DC bus, above-mentioned electric current and voltage carry out after electrical isolation and transformation of coefficient through the second DC voltage and current acquisition module (27), obtain the detection voltage U of the 2nd DC bus _dc2with the detection electric current I on the 2nd DC bus _dc2, U _dc2with the given signal of the 2nd DC bus-bar voltage

try to achieve error signal by the 7th adder (25), this error signal is inputed to the constant voltage mode terminal of mode converter (24), the electric current I on the 2nd DC bus _dc2with the given value of current value on the 2nd DC bus

try to achieve error signal by the 8th adder (26), this error signal is inputed to the constant current mode terminal of mode converter (24), mode converter (24) carries out model selection, carry out after ratio, integral adjustment through the 5th pi regulator (23), obtain the given value of current value on the 1st DC bus

with the operating current I on the 1st DC bus _dc1try to achieve error signal by the 6th adder (22), this error signal is input to the positive-going transition end of power conversion direction controller (21);

7) power conversion direction controller (21) is determined forward and reverse conversion of power, carry out the conversion of voltage to frequency through Voltage-to-frequency Converter (20) again, by driving signal generation module (19) to form the upper and lower bridge arm complementary signal with 180 ° of duty ratios, finally generate g1 and drive signal, g2 to drive signal, g3 to drive signal and g4 to drive signal.

Images