Energy storage converter and high-voltage ride-through control method

Abstract

The invention discloses an energy storage converter and a control method of high voltage ride through, the energy storage converter comprises a direct current side switch, a DCDC power module, a DC / AC power module, an output filtering module and a controller, a first end of the direct current side switch is connected with an energy storage direct current side positive electrode, a second end of the direct current side switch is connected with an input side positive electrode of the DC / AC power module, and the output filtering module is connected with the controller. The negative electrode of the input side of the DCDC power module is connected with the negative electrode of the energy storage direct current side, the positive electrode of the output side of the DCDC power module is connected with the positive electrode of the input side of the DC / AC power module, the negative electrode of the output side of the DCDC power module is connected with the negative electrode of the input side of the DC / AC power module, and three-phase lines output by the DC / AC power module are connected with the input end of the output filtering module. The output end of the output filtering module is connected with a power grid side, the controller is used for controlling the direct current side switch, the DCDC power module, the DC / AC power module and the output filtering module, and the DCDC power module comprises an H-bridge circuit composed of four IGBT modules, a super capacitor module connected in series with the H-bridge circuit and an inductor.

Description

Technical Field

[0001] The present invention relates to the field of energy storage power systems, and in particular to an energy storage converter and a high voltage ride-through control method. Background Art

[0002] In the current energy storage power system, according to national standards, energy storage converters need to have high voltage ride-through capability when the grid suddenly rises. That is, when the grid voltage rises, the energy storage converter needs to provide reactive power support, and after the grid is restored, it needs to quickly restore power. In some specific application scenarios, the grid may require the energy storage system to continue to provide active power during high voltage ride-through to maintain stable power supply.

[0003] In the existing high-voltage ride-through technology, the energy storage converter can only provide reactive power support but cannot provide the necessary active power support during high-voltage ride-through, and is not suitable for certain specific application scenarios.

[0004] In view of this, how to provide an energy storage converter that can provide certain active power support during high-voltage ride-through and a control method for high-voltage ride-through is a technical problem that needs to be solved in the technical field. Summary of the invention

[0005] The main advantage of the present invention is that it provides an energy storage inverter. When the energy storage inverter encounters a high-voltage ride-through condition and the voltage on the energy storage DC side is low, the energy storage inverter can provide certain active power support while providing high-voltage support without reducing the power efficiency of the operation process, which is beneficial to improving the grid adaptability of the energy storage inverter.

[0006] Another advantage of the present invention is that it provides a control method for high-voltage crossing based on the energy storage converter, which can quickly connect the energy storage DC side to the energy storage converter after the energy storage converter completes high-voltage crossing, thereby reducing the recovery time of active power after fault crossing and ensuring that the energy storage converter provides active support during the entire switching process.

[0007] Accordingly, according to an embodiment of the present invention, an energy storage converter having at least one of the aforementioned advantages includes: A DC side switch, a DCDC power module, a DC / AC power module, an output filter module and a controller, wherein the first end of the DC side switch is suitable for connecting to the energy storage DC side positive electrode of the energy storage DC side, the second end of the DC side switch is connected to the DC / AC power module input side positive electrode of the DC / AC power module, the DCDC power module input side negative electrode of the DCDC power module is suitable for connecting to the energy storage DC side negative electrode of the energy storage DC side, the DCDC power module output side positive electrode of the DCDC power module is connected to the DC / AC power module input side positive electrode of the DC / AC power module, and the D The negative electrode on the output side of the DCDC power module of the CDC power module is connected to the negative electrode on the input side of the DC / AC power module of the DC / AC power module, the three-phase line of the output of the DC / AC power module is connected to the input end of the output filter module, the output end of the output filter module is suitable for being connected to the grid side, the controller is configured to control the DC side switch, the DCDC power module, the DC / AC power module and the output filter module, the DCDC power module includes an H-bridge circuit composed of four IGBT modules G1, G2, G3, and G4, and a supercapacitor module and an inductor connected in series to the H-bridge circuit.

[0008] Accordingly, the present invention further provides a high voltage ride through control method, which is based on the energy storage converter and comprises the following steps: Step S1: Obtain the voltage V detected by the first voltage and current sensing module bat and current I bat ; Get the voltage V detected by the second voltage and current sensing module cap and current I cap ; Get the voltage V detected by the third voltage and current sensing module net and current I net ; Get the voltage V on the DC side of the energy storage bat0 ; Step S2: Obtain the target active power P that the energy storage converter needs to provide out_ref and target reactive power Q out_ref ; According to the voltage V net and current I net Calculate the actual active power P actually output by the energy storage converter out and actual reactive power Q out ; Step S3: Target active power P out_ref The actual active power P out The difference is used as the input of the first active PI control, and the output of the first active PI control is the voltage V d ; With the target reactive power Q out-ref The actual reactive power Q outThe difference is used as the input of the first reactive PI control, and the output of the first reactive PI control is the voltage V q ; Step S4: According to the voltage V net and current I net , the d-axis voltage V is obtained through dq transformation d1 , q-axis voltage V q1 ; Step S5: With voltage V d With voltage V d1 The difference is used as the input of the second active PI control, and the output of the second active PI control is the voltage V d2 ; With voltage V q With voltage V q1 The difference is used as the input of the second reactive PI control, and the output of the second reactive PI control is the voltage V q2 ; According to the voltage V d2 and voltage V q2 , calculate and generate PWM signals for the IGBT modules of the DC / AC power modules; Step S6: Determine the voltage V net With the first voltage threshold V set net_ref If V net >V net_ref , then execute step S61, if V net ≤V net_ref , then execute step S62; Step S62: Determine the state of the DC side switch. The state mark K of the DC side switch DC_flag The initial value is 0, indicating that the DC side switch is closed, K DC_flag Equal to 1 means that the DC side switch is disconnected, where K DC_flag =1, controls the DCDC power module to enter the boost mode, and sets the target output voltage of the DCDC power module to the voltage V bat0 , with voltage V bat0 With voltage V bat The difference is used as the input of the PI control of the DCDC power module, and the duty cycle of the IGBT modules G1 and G4 of the DCDC power module is controlled according to the output of the PI control of the DCDC power module until the voltage V bat0 With voltage V bat The absolute value of the difference is less than the set second voltage threshold V th When the DC side switch is closed, the state mark K of the DC side switch is changed DC_flag Set to 0, then jump back to step S1; if K DC_flag =0, controls the DCDC power module to enter the buck mode, and sets the target output voltage of the DCDC power module to the voltage V bat -Vth , with voltage V bat -V th With voltage V cap The difference is used as the input of the PI control of the DCDC power module, and the duty ratios of the IGBT modules G2 and G3 of the DCDC power module are controlled according to the output of the PI control of the DCDC power module, and then the process returns to step S1; Step S61 further comprises the steps of: Step S611, calculate the third voltage threshold V bat2 ,in, ; Calculate the active power P on the DC side of the energy storage bat ,in, ; Step S612: Determine the third voltage threshold V bat2 With voltage V bat0 The size of the energy storage DC side active power P bat Add the set active power threshold P th The sum of the target active power P out_ref If V bat2 >V bat0 And P bat +P th <P out_ref , then execute step S613, otherwise, jump back to step S1; Step S613: Determine the state of the DC side switch. If K DC_flag =1, then execute step S614, if K DC_flag =0, first disconnect the DC side switch, and mark the state of the DC side switch K DC_flag Set to 1 and start timing, then execute step S614; Step S614: Control the DCDC power module to enter the boost mode, and set the target output voltage of the DCDC power module to V bat2 , with V bat2 With voltage V bat The difference is used as the input of the PI control of the DCDC power module, and the duty ratio of the IGBT modules G1 and G4 of the DCDC power module is controlled according to the output of the PI control of the DCDC power module; Step S615: Determine K DC_flag The time equal to 1 is equal to the set maximum duration of high pressure crossing T max The size of K DC_flag The time equal to 1 is greater than T max , disconnect the AC side switch, otherwise, jump back to step S1.

[0009] The above and other advantages of the present invention will be fully reflected in conjunction with the following description and the accompanying drawings.

[0010] The above and other advantages and features of the present invention are fully reflected in the following detailed description of the present invention and the accompanying drawings.

[0011] The content of the invention is not to be regarded as identifying the essential technical features of the invention, nor is it to be regarded as limiting the protection scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of an energy storage converter according to an embodiment of the present invention.

[0013] Figure 2 is a schematic diagram of a high voltage ride through control method of an energy storage converter according to an embodiment of the present invention.

[0014] Figure 3 is a schematic diagram of step S61 of the high voltage ride through control method according to an embodiment of the present invention.

[0015] In the figure: 1. Energy storage converter; 11. DC side switch; 111. First end; 112. Second end; 12. DCDC power module; 121. Negative pole on input side of DCDC power module; 122. Positive pole on output side of DCDC power module; 123. Negative pole on output side of DCDC power module; 124. Super capacitor module; 13. DC / AC power module; 131. Positive pole on input side of DC / AC power module; 132. Negative pole on input side of DC / AC power module; 133. Three-phase line; 14. Output filter module; 141. Input end; 142. Output end; 143. AC side switch; 15. Controller; CV1. First voltage and current sensor module; CV2. Second voltage and current sensor module; CV3. Third voltage and current sensor module; G1-G10. IGBT module; L dc , inductance; C d1 -C d2 , capacitor; R f , filter resistance; L f , filter inductor; C f , filter capacitor; 2. energy storage DC side; 21. energy storage DC side positive pole; 22. energy storage DC side negative pole; 3. grid side. DETAILED DESCRIPTION

[0016] The following description is provided to enable those skilled in the art to implement the present invention. Other obvious replacements, modifications and variations may occur to those skilled in the art. Therefore, the scope of protection of the present invention should not be limited to the exemplary embodiments described herein.

[0017] Those skilled in the art should understand that, unless otherwise specified herein, the terms "one" and "an" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple.

[0018] Those skilled in the art should understand that, unless otherwise specified herein, the directions or positions referred to by the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the directions or positions shown in the drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the devices or elements involved must have a specific direction or position. Therefore, the above terms should not be understood as limiting the present invention.

[0019] Referring to the accompanying drawings of the present invention Figure 1 , an energy storage converter 1 according to an embodiment of the present invention is illustrated. The energy storage converter 1 includes a DC side switch 11, a DCDC power module 12, a DC / AC power module 13, an output filter module 14 and a controller 15. The first end 111 of the DC side switch 11 is connected to the energy storage DC side positive electrode 21 of the energy storage DC side 2, and the second end 112 of the DC side switch 11 is connected to the DC / AC power module input side positive electrode 131 of the DC / AC power module 13. The DCDC power module input side negative electrode 121 of the DCDC power module 12 is connected to the energy storage DC side negative electrode 22 of the energy storage DC side 2, the DCDC power module output side positive electrode 122 of the DCDC power module 12 is connected to the DC / AC power module input side positive electrode 131 of the DC / AC power module 13, and the DCDC power module output side negative electrode 123 of the DCDC power module 12 is connected to the DC / AC power module input side negative electrode 132 of the DC / AC power module 13. The three-phase line 133 of the output of the DC / AC power module 13 is connected to the input end 141 of the output filter module 14, and the output end 142 of the output filter module 14 is connected to the grid side 3. The controller 15 is configured to control the DC side switch 11, the DCDC power module 12, the DC / AC power module 13 and the output filter module 14.

[0020] In particular, the DCDC power module 12 includes an H-bridge circuit composed of four IGBT modules G1, G2, G3, and G4, a super capacitor module 124 connected in series to the H-bridge circuit, and an inductor L dcThe control ends of the four IGBT modules G1, G2, G3, and G4 are respectively connected to the controller 15 for communication, so as to control the actions of the four IGBT modules G1, G2, G3, and G4 through the controller 15, thereby realizing the control of the boost mode and the buck mode of the DCDC power module 12. When the DCDC power module 12 is in the boost mode, the IGBT modules G1 and G4 are in action, the IGBT modules G2 and G3 are stopped, and the electric energy is boosted from the supercapacitor module 124 to the DC / AC power module 13; when the DCDC power module 12 is in the buck mode, the IGBT modules G1 and G4 are stopped, the IGBT modules G2 and G3 are in action, and the electric energy is stepped down from the DC / AC power module 13 to the supercapacitor module 124. Based on the DCDC power module 12 configured with the supercapacitor module 124 of the present invention, when the energy storage converter 1 encounters a high-voltage ride-through condition and the voltage of the energy storage DC side 2 is low, the energy storage converter 1 can provide a certain amount of active power support while providing high-voltage support, without reducing the power efficiency of the operation process, which is beneficial to improving the grid adaptability of the energy storage converter 1.

[0021] Furthermore, the DC / AC power module 13 includes six IGBT modules G5, G6, G7, G8, G9, G10 and two capacitors C d1 , C d2 The control ends of the six IGBT modules G5, G6, G7, G8, G9, and G10 are respectively connected to the controller 15 for communication, so that the controller 15 controls the actions of the six IGBT modules G5, G6, G7, G8, G9, and G10.

[0022] Furthermore, the output filter module 14 includes three filter resistors R f , three filter inductors L f , three filter capacitors C f and three AC side switches 143. The three AC side switches 143 are arranged close to the output end 142 of the output filter module 14, and the corresponding filter resistors R f , the filter inductor L f and the AC side switch 143 are connected in series in the corresponding branches in sequence, and the three filter capacitors C f One end of each of the two filters is connected together, and the other end is connected to the corresponding branch, and the connection point between the other end and the corresponding branch is located at the corresponding filter inductor L f and between the AC side switch 143 .

[0023] Furthermore, the energy storage converter 1 also includes a first voltage and current sensing module CV1, a second voltage and current sensing module CV2 and a third voltage and current sensing module CV3. The detection point of the first voltage and current sensing module CV1 is located at the second end 112 of the DC side switch 11, and is used to detect the DC voltage and current on the input side of the energy storage converter 1. When the DC side switch 11 is closed, the first voltage and current sensing module CV1 is also equivalent to detecting the voltage of the energy storage DC side 2 and the current flowing between the energy storage DC side 2 and the energy storage converter 1. The detection point of the second voltage and current sensing module CV2 is located between the positive electrode of the super capacitor module 124 and the inductor L dc , for detecting the DC voltage and current of the supercapacitor module 124. The detection point of the third voltage and current sensing module CV3 is located between the output end 142 of the output filter module 14 and the grid side 3, and is used to detect the AC voltage and current on the output side of the energy storage converter 1. The first voltage and current sensing module CV1, the second voltage and current sensing module CV2 and the third voltage and current sensing module CV3 are respectively connected to the controller 15 for communication, so as to obtain the corresponding voltage value and current value through the controller 15. The controller 15 is also connected to the energy storage DC side 2 for communication, so as to obtain the voltage of the energy storage DC side 2. The controller 15 is also connected to the energy management controller of the system for communication, so as to obtain the target active power and target reactive power that the energy storage converter 1 needs to provide.

[0024] According to another aspect of the present invention, Figure 2 and attached Figure 3 As shown, based on the above-mentioned energy storage converter 1 of the present invention, the present invention further provides a control method for high voltage ride through, comprising the following steps: Step S1: Obtain the voltage V detected by the first voltage and current sensing module bat and current I bat ; Get the voltage V detected by the second voltage and current sensing module cap and current I cap ; Get the voltage V detected by the third voltage and current sensing module net and current I net ; Get the voltage V on the DC side of the energy storage bat0 ; Step S2: Obtain the target active power P that the energy storage converter needs to provide out_ref and target reactive power Q out_ref ; According to the voltage V net and current I net Calculate the actual active power P actually output by the energy storage converter out and actual reactive power Q out ; Step S3: Target active power P out_ref The actual active power P out The difference is used as the input of the first active PI control, and the output of the first active PI control is the voltage V d ; With the target reactive power Q out-ref The actual reactive power Q out The difference is used as the input of the first reactive PI control, and the output of the first reactive PI control is the voltage V q ; Step S4: According to the voltage V net and current I net , the d-axis voltage V is obtained through dq transformation d1 , q-axis voltage V q1 ; Step S5: With voltage V d With voltage V d1 The difference is used as the input of the second active PI control, and the output of the second active PI control is the voltage V d2 ; With voltage V q With voltage V q1 The difference is used as the input of the second reactive PI control, and the output of the second reactive PI control is the voltage V q2 ; According to the voltage V d2 and voltage V q2 , calculate and generate PWM signals for the IGBT modules of the DC / AC power modules; Step S6: Determine the voltage V net With the first voltage threshold V set net_ref If V net >V net_ref , then execute step S61, if V net ≤V net_ref , then execute step S62; Step S62: Determine the state of the DC side switch. The state mark K of the DC side switch DC_flag The initial value is 0, indicating that the DC side switch is closed, K DC_flag Equal to 1 means that the DC side switch is disconnected, where K DC_flag =1, controls the DCDC power module to enter the boost mode, and sets the target output voltage of the DCDC power module to the voltage V bat0 , with voltage V bat0 With voltage V bat The difference is used as the input of the PI control of the DCDC power module, and the duty cycle of the IGBT modules G1 and G4 of the DCDC power module is controlled according to the output of the PI control of the DCDC power module until the voltage V bat0 With voltage V batThe absolute value of the difference is less than the set second voltage threshold V th When the DC side switch is closed, the state mark K of the DC side switch is changed DC_flag Set to 0, then jump back to step S1; if K DC_flag =0, controls the DCDC power module to enter the buck mode, and sets the target output voltage of the DCDC power module to the voltage V bat -V th , with voltage V bat -V th With voltage V cap The difference is used as the input of the PI control of the DCDC power module, and the duty ratios of the IGBT modules G2 and G3 of the DCDC power module are controlled according to the output of the PI control of the DCDC power module, and then the process returns to step S1; Step S61 further comprises the steps of: Step S611, calculate the third voltage threshold V bat2 ,in, ; Calculate the active power P on the DC side of the energy storage bat ,in, ; Step S612: Determine the third voltage threshold V bat2 With voltage V bat0 The size of the energy storage DC side active power P bat Add the set active power threshold P th The sum of the target active power P out_ref If V bat2 >V bat0 And P bat +P th <P out_ref , then execute step S613, otherwise, jump back to step S1; Step S613: Determine the state of the DC side switch. If K DC_flag =1, then execute step S614, if K DC_flag =0, first disconnect the DC side switch, and mark the state of the DC side switch K DC_flag Set to 1 and start timing, then execute step S614; Step S614: Control the DCDC power module to enter the boost mode, and set the target output voltage of the DCDC power module to V bat2 , with V bat2 With voltage V bat The difference is used as the input of the PI control of the DCDC power module, and the duty ratio of the IGBT modules G1 and G4 of the DCDC power module is controlled according to the output of the PI control of the DCDC power module; Step S615: Determine KDC_flag The time equal to 1 is equal to the set maximum duration of high pressure crossing T max The size of K DC_flag The time equal to 1 is greater than T max , disconnect the AC side switch, otherwise, jump back to step S1.

[0025] It is worth mentioning that the control method of the high-voltage ride-through can quickly connect the energy storage DC side 2 to the energy storage converter 1 after the energy storage converter 1 completes the high-voltage ride-through. Before and after the DC side switch 11 is closed, the super capacitor module 124 and the DCDC power module 12 provide active support to ensure that the energy storage converter 1 provides active support during the entire switching process, reducing the recovery time of active power after fault ride-through. In addition, the control method of the high-voltage ride-through, in the high-voltage ride-through process, the super capacitor module 124 and the DCDC power module 12 provide active support, which has more beneficial practical significance compared to the traditional ride-through method that cannot provide active support.

[0026] Those skilled in the art will appreciate that the above embodiments are merely examples, wherein features of different embodiments may be combined with each other to obtain implementation methods that are easily conceivable based on the contents disclosed in the present invention but are not explicitly indicated in the drawings.

[0027] Those skilled in the art should understand that the above description and the embodiments shown in the drawings are only for illustrative explanation of the present invention, rather than for limitation of the present invention. All equivalent implementations, modifications and improvements within the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An energy storage converter, characterized in that: include: A DC side switch, a DCDC power module, a DC / AC power module, an output filter module and a controller, wherein the first end of the DC side switch is suitable for connecting to the energy storage DC side positive electrode of the energy storage DC side, the second end of the DC side switch is connected to the DC / AC power module input side positive electrode of the DC / AC power module, the DCDC power module input side negative electrode of the DCDC power module is suitable for connecting to the energy storage DC side negative electrode of the energy storage DC side, the DCDC power module output side positive electrode of the DCDC power module is connected to the DC / AC power module input side positive electrode of the DC / AC power module, and the D The negative electrode on the output side of the DCDC power module of the CDC power module is connected to the negative electrode on the input side of the DC / AC power module of the DC / AC power module, the three-phase line of the output of the DC / AC power module is connected to the input end of the output filter module, the output end of the output filter module is suitable for being connected to the grid side, the controller is configured to control the DC side switch, the DCDC power module, the DC / AC power module and the output filter module, the DCDC power module includes an H-bridge circuit composed of four IGBT modules G1, G2, G3, and G4, and a supercapacitor module and an inductor connected in series to the H-bridge circuit.

2. The energy storage converter according to claim 1, characterized in that: It also includes a first voltage and current sensing module, a second voltage and current sensing module and a third voltage and current sensing module, wherein the detection point of the first voltage and current sensing module is located at the second end of the DC side switch, the detection point of the second voltage and current sensing module is located between the positive electrode of the supercapacitor module and the inductor, and the detection point of the third voltage and current sensing module is located between the output end of the output filter module and the grid side.

3. The energy storage converter according to claim 2, characterized in that: When the DCDC power module is in boost mode, IGBT modules G1 and G4 operate, and IGBT modules G2 and G3 stop operating; when the DCDC power module is in buck mode, IGBT modules G1 and G4 stop operating, and IGBT modules G2 and G3 operate.

4. The energy storage converter according to claim 3, characterized in that: The DC / AC power module includes a three-phase bridge circuit consisting of six IGBT modules G5, G6, G7, G8, G9, G10 and two capacitors.

5. The energy storage converter according to claim 4, characterized in that: The output filter module includes three AC side switches, and the three AC side switches are arranged close to the output end of the output filter module.

6. The energy storage converter according to claim 5, characterized in that: The output filter module also includes three filter resistors, three filter inductors and three filter capacitors. The corresponding filter resistors, filter inductors and AC side switches are connected in series in the corresponding branches in sequence. One ends of the three filter capacitors are connected together, and the other ends are respectively connected to the corresponding branches, and the connection between the other ends and the corresponding branches is located between the corresponding filter inductors and the AC side switches.

7. The energy storage converter according to claim 6, characterized in that: The first voltage and current sensing module, the second voltage and current sensing module and the third voltage and current sensing module are respectively connected to the controller for communication.

8. The energy storage converter according to claim 7, characterized in that: The controller is also adapted to be connected to the energy storage DC side for communication, so as to obtain the voltage of the energy storage DC side.

9. The energy storage converter according to claim 8, characterized in that: The controller is also suitable for being connected to the energy management controller of the system for communication, so as to obtain the target active power and target reactive power that the energy storage converter needs to provide.

10. A high voltage ride through control method, based on the energy storage converter according to any one of claims 1 to 9, characterized in that: Includes steps: Step S1: Obtain the voltage V detected by the first voltage and current sensing module bat and current I bat ; Get the voltage V detected by the second voltage and current sensing module cap and current I cap ; Get the voltage V detected by the third voltage and current sensing module net and current I net ; Get the voltage V on the DC side of the energy storage bat0 ; Step S2: Obtain the target active power P that the energy storage converter needs to provide out_ref and target reactive power Q out_ref ; According to the voltage V net and current I net Calculate the actual active power P actually output by the energy storage converter out and actual reactive power Q out ; Step S3: Target active power P out_ref The actual active power P out The difference is used as the input of the first active PI control, and the output of the first active PI control is the voltage V d ; With the target reactive power Q out-ref The actual reactive power Q out The difference is used as the input of the first reactive PI control, and the output of the first reactive PI control is the voltage V q ; Step S4: According to the voltage V net and current I net , the d-axis voltage V is obtained through dq transformation d1 , q-axis voltage V q1 ; Step S5: With voltage V d With voltage V d1 The difference is used as the input of the second active PI control, and the output of the second active PI control is the voltage V d2 ; With voltage V q With voltage V q1 The difference is used as the input of the second reactive PI control, and the output of the second reactive PI control is the voltage V q2 ; According to the voltage V d2 and voltage V q2 , calculate and generate PWM signals for the IGBT modules of the DC / AC power modules; Step S6: Determine the voltage V net With the first voltage threshold V set net_ref If V net >V net_ref , then execute step S61, if V net ≤V net_ref , then execute step S62; Step S62: Determine the state of the DC side switch. The state mark K of the DC side switch DC_flag The initial value is 0, indicating that the DC side switch is closed, K DC_flag Equal to 1 means that the DC side switch is disconnected, where K DC_flag =1, controls the DCDC power module to enter the boost mode, and sets the target output voltage of the DCDC power module to the voltage V bat0 , with voltage V bat0 With voltage V bat The difference is used as the input of the PI control of the DCDC power module, and the duty cycle of the IGBT modules G1 and G4 of the DCDC power module is controlled according to the output of the PI control of the DCDC power module until the voltage V bat0 With voltage V bat The absolute value of the difference is less than the set second voltage threshold V th When the DC side switch is closed, the state mark K of the DC side switch is changed DC_flag Set to 0, then jump back to step S1; if K DC_flag =0, controls the DCDC power module to enter the buck mode, and sets the target output voltage of the DCDC power module to the voltage V bat -V th , with voltage V bat -V th With voltage V cap The difference is used as the input of the PI control of the DCDC power module, and the duty ratios of the IGBT modules G2 and G3 of the DCDC power module are controlled according to the output of the PI control of the DCDC power module, and then the process returns to step S1; Step S61 further comprises the steps of: Step S611, calculate the third voltage threshold V bat2 ,in, ; Calculate energy storage Active power P on the DC side bat ,in, ; Step S612: Determine the third voltage threshold V bat2 With voltage V bat0 The size of the energy storage DC side active power P bat Add the set active power threshold P th The sum of the target active power P out_ref If V bat2 >V bat0 And P bat +P th <P out_ref , then execute step S613, otherwise, jump back to step S1; Step S613: Determine the state of the DC side switch. If K DC_flag =1, then execute step S614, if K DC_flag =0, first disconnect the DC side switch, and mark the state of the DC side switch K DC_flag Set to 1 and start timing, then execute step S614; Step S614: Control the DCDC power module to enter the boost mode, and set the target output voltage of the DCDC power module to V bat2 , with V bat2 With voltage V bat The difference is used as the input of the PI control of the DCDC power module, and the duty ratio of the IGBT modules G1 and G4 of the DCDC power module is controlled according to the output of the PI control of the DCDC power module; Step S615: Determine K DC_flag The time equal to 1 is equal to the set maximum duration of high pressure crossing T max The size of K DC_flag The time equal to 1 is greater than T max , disconnect the AC side switch, otherwise, jump back to step S1.

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