Anti-countercurrent control method and system for grid-connected energy storage converter

Abstract

The invention discloses an anti-countercurrent control method for a grid-connected energy storage converter. The anti-countercurrent control method comprises the steps that a current real-time sampling device is arranged at a total load outlet; acquiring a power measurement result and load current sampling data in real time; calculating to obtain a filtering power value, a power given value and a current given value based on the obtained data; calculating to obtain a three-phase modulation wave signal based on the load current sampling data and the current given value; and calculating to obtain a gate pole control signal of the grid-connected energy storage converter, and controlling a power electronic switch in the grid-connected energy storage converter to realize anti-countercurrent control of the grid-connected energy storage converter. The invention also provides a system for realizing the anti-countercurrent control method of the grid-connected energy storage converter. By acquiring the current information of the load in real time and combining a power control scheme and a current control scheme, the anti-countercurrent control of the grid-connected energy storage converter is realized, the reliability is higher, and the accuracy is better.

Description

Technical Field

[0001] The present invention belongs to the field of electrical automation, and in particular relates to a backflow prevention control method and system for a grid-connected energy storage converter. Background Art

[0002] With the development of economy and technology and the improvement of people's living standards, electricity has become an indispensable secondary energy source in people's production and life, bringing endless convenience to people's production and life. Therefore, ensuring the stable and reliable supply of electricity has become one of the most important tasks of the power system.

[0003] The grid-connected energy storage inverter is an important component of the power system. It is connected to the load in the microgrid and connected to the large power grid through a transformer. When the system is running stably, the energy storage inverter and the large power grid jointly output power to supply power to the load; when the load power is switched on and off, resulting in a sudden decrease in power and the power reduction value is greater than the power supply of the power grid, the energy storage inverter will continue to maintain the original power output before receiving the power adjustment command from the monitoring system, which will cause the power output of the energy storage to be greater than the power consumption of the load, causing the energy storage inverter to reverse power to the power grid. The above process is analyzed in detail as follows:

[0004] like Figure 1 The figure shows the principle diagram of the anti-reverse flow technology of the existing grid-connected energy storage converter: a power detection device is installed between the point of common coupling (PCC) and the low-voltage side of the transformer. The power detection device transmits the real-time detected power size and direction to the energy management system (EMS) through communication. The EMS adjusts the power output size or shuts down the energy storage converter according to the power size and direction. When the load increases, the power output of the energy storage converter is increased; when the load decreases, the power output of the energy storage converter is reduced; this control process can prevent the power output of the entire system from being sent back to the grid.

[0005] However, this control method has a slow adjustment response speed: due to sudden changes in power, it needs to be detected and then communicated to the EMS. After calculation, the EMS sends the power adjustment command to the energy storage inverter through the communication system, and the energy storage inverter responds to the power adjustment command; the entire processing time will reach seconds, and although the period before the response is very short, the energy storage inverter will still output according to the original power size, resulting in reverse power to the grid; and this control method has an adjustment lag: the power detection device will only respond when it detects that reverse power has occurred (reverse power first and then processing); this is a passive processing method, and a small amount of reverse power will still be generated during the processing process.

[0006] In addition, the existing power closed-loop control strategies of grid-connected energy storage converters are as follows: Figure 2 As shown: The control process is as follows: First, the voltage and current sampling value u of the PCS AC end is S and i S , Park transformation is performed, and the controller can convert the AC quantity in the ABC three-phase coordinate system into the orthogonal component u in the dq two-phase rotating coordinate system Sd 、u Sq 、i Sd and i Sq ; Then, the current and voltage sampling values ​​under the d-axis and q-axis coordinate decomposition are substituted into the power calculation module to obtain the instantaneous power Pout and Qout output by the current PCS, and the filtered power values ​​Pfil and Qfil are obtained. The difference between the active given value Pref received from the EMS and Pfil is proportionally integrated and limited, and the output is the command value Idref of the inner current loop. Similarly, the reactive given values ​​Qref and Qfil received from the EMS are similarly processed to obtain the command value Iqref of the inner current loop. After several control cycles (i.e., power electronic switching cycles), the active and reactive feedback values ​​can be made into the difference-free control results of Pref and Qref, and the output of the energy storage converter can follow the new given value issued by the EMS after a sudden load change.

[0007] However, with this control method, although the PCS responds quickly and accurately to sudden changes in load power after receiving the command, the output power of the PCS remains unchanged during the EMS sampling, calculation, and communication processes. At this time, the power generated by the grid-connected PCS in the microgrid will be greater than the total power consumption in the microgrid, and part of the PCS output power will be fed back to the grid side through the grid-connected transformer, thereby generating a small amount of reverse power. Summary of the invention

[0008] One of the purposes of the present invention is to provide a reverse flow prevention control method for a grid-connected energy storage converter with high reliability and good accuracy.

[0009] A second object of the present invention is to provide a system for implementing the anti-backflow control method of the grid-connected energy storage converter.

[0010] The anti-backflow control method of the grid-connected energy storage converter provided by the present invention comprises the following steps:

[0011] S1. Set up a real-time current sampling device at the total load outlet;

[0012] S2 real-time acquisition of power detection device power measurement results, and the current real-time sampling device load current sampling data;

[0013] S3. In the power outer loop control process, the filtered power value is calculated based on the power measurement result, the power set value is calculated based on the load current sampling data, and then the current set value is calculated based on the filtered power value and the power set value;

[0014] S4. In the current inner loop control process, based on the load current sampling data and the current given value, a three-phase modulation wave signal is calculated;

[0015] S5. According to the three-phase modulation wave signal obtained in step S4, the gate control signal of the grid-connected energy storage converter is calculated, and the power electronic switch in the grid-connected energy storage converter is controlled to realize the anti-reverse flow control of the grid-connected energy storage converter.

[0016] The step S3 of calculating the filter power value based on the power measurement result specifically includes the following steps:

[0017] Based on the power measurement results, the PCS AC terminal voltage sampling value u S And the current sampling value i S , perform Park transformation, convert the AC quantity in the ABC three-phase coordinate system into the orthogonal component in the dq two-phase rotating coordinate system, and obtain the voltage d-axis component u Sd , voltage q-axis component u Sq , current d-axis component i Sd and the current q-axis component i Sq ;

[0018] The calculated active instantaneous power Pout is Pout = u Sd i Sd +u Sq i Sq , the reactive instantaneous power Qout is calculated to be Qout = u Sd i Sq -u Sq i Sd ;

[0019] Pout and Qout are filtered through the inertia link to obtain the active filter power value Pfil and the reactive filter power value Qfil; where the inertia link is expressed as T is the time constant of the inertia link.

[0020] The step S3 of calculating the power given value based on the load current sampling data specifically includes the following steps:

[0021] Based on the load current sampling data, the load active current i ZP and load reactive current i ZQ Perform coordinate transformation to obtain the load d-axis current i Zd and load q-axis current i Zq ;

[0022] The calculated load active power Pload is Pload=u Sd i Zd +u Sq i Zq , the load reactive power Qload is calculated as Qload = u Sd i Zq -u Sq i Zd ;

[0023] The load active power change value ΔPload is calculated to be ΔPload=Pload'-Pload, and the load reactive power change value ΔQload is calculated to be ΔQload=Qload'-Qload; wherein Pload' is the load active power of the previous control cycle, and Qload' is the load reactive power of the previous control cycle;

[0024] The calculated active power given value Pref' is Pref'=Pref-ΔPload, and the calculated reactive power given value Pref' is Qref'=Qref-ΔQload; wherein Pref is the active power given value of the system, and Qref is the reactive power given value of the system.

[0025] The step S3 of calculating the current given value according to the filtered power value and the power given value specifically includes the following steps:

[0026] The calculated active power change value ΔP is ΔP=Pref'-Pfil, and the calculated reactive power change value ΔQ is ΔQ=Qref'-Qfil;

[0027] The active power change value ΔP is processed by the proportional integral link and then by the limiting link to obtain the current d-axis given value Idref;

[0028] The reactive power change value ΔQ is processed by the proportional integral link and then by the limiting link to obtain the current q-axis given value Iqref.

[0029] The step S4 of calculating the three-phase modulation wave signal based on the load current sampling data and the current given value specifically includes the following steps:

[0030] The d-axis component of the current i Sd The current d-axis filter component Idfil is obtained by filtering through the inertia link; the current q-axis component i Sq Through the inertia link filtering, the current q-axis filter component Iqfil is obtained;

[0031] The calculated current d-axis change ΔId is ΔId=Idref-Idfil, and the calculated current q-axis change ΔIq is ΔIq=Iqref-Iqfil;

[0032] The current d-axis change ΔId is processed through a proportional integral link to obtain the d-axis first control quantity Idc1; the current d-axis filter component Idfil is processed through a proportional link with a proportional coefficient of ωL to obtain the q-axis second control quantity Iqc2;

[0033] The current q-axis change ΔIq is processed through a proportional integral link to obtain the q-axis first control quantity Iqc1; the current q-axis filter component Iqfil is processed through a proportional link with a proportional coefficient of ωL to obtain the d-axis second control quantity Idc2;

[0034] Calculate the voltage d-axis control quantity u d for u d =u Sd +Idc1-Idc2, calculate the voltage q-axis control value u q for u q =u Sq +Iqc1+Iqc2;

[0035] will u d and u q The voltage d-axis reference value U is obtained by performing the limiting process through the limiting link. dref and voltage q-axis reference quantity U qref ; Then U dref and U qref Through 2r / 3s transformation, we can get the A phase voltage reference U Aref , B phase voltage reference quantity U Bref and C phase voltage reference quantity U Cref ;

[0036] Will U Aref , U Bref and U Cref , as a three-phase modulated wave signal.

[0037] Step S5, according to the three-phase modulation wave signal obtained in step S4, calculates the gate control signal of the grid-connected energy storage converter to control the power electronic switch in the grid-connected energy storage converter, specifically includes the following steps:

[0038] According to the three-phase modulation wave signal obtained in step S4, a PWM scheme is adopted to generate a gate control signal of the grid-connected energy storage converter, and the three-phase inverter-independent power electronic switch in the grid-connected energy storage converter is controlled.

[0039] The present invention also provides a system for implementing the anti-backflow control method of the grid-connected energy storage converter, comprising a device setting module, a data sampling module, a given value calculation module, a modulation calculation module and an anti-backflow control module; the device setting module, the data sampling module, the given value calculation module, the modulation calculation module and the anti-backflow control module are connected in series in sequence; the device setting module is used to set a current real-time sampling device at the total load outlet, and upload the data information to the data sampling module; the data sampling module is used to obtain the power measurement result of the power detection device and the load current sampling data of the current real-time sampling device in real time according to the received data information, and upload the data information to the given value calculation module; the given value calculation module is used to obtain the power measurement result of the power detection device and the load current sampling data of the current real-time sampling device according to the received data information, and upload the data information to the given value calculation module; the given value calculation module is used to obtain the power measurement result of the power detection device and the load current sampling data of the current real-time sampling device according to the received data information at the power outlet During the inner loop control process, the filtered power value is calculated based on the power measurement result, the power given value is calculated based on the load current sampling data, and then the current given value is calculated based on the filtered power value and the power given value, and the data information is uploaded to the modulation calculation module; the modulation calculation module is used to calculate the three-phase modulation wave signal based on the load current sampling data and the current given value according to the received data information during the current inner loop control process, and upload the data information to the anti-reverse flow control module; the anti-reverse flow control module is used to calculate the gate control signal of the grid-connected energy storage inverter according to the received data information and the obtained three-phase modulation wave signal, control the power electronic switch in the grid-connected energy storage inverter, and realize the anti-reverse flow control of the grid-connected energy storage inverter.

[0040] The anti-reverse flow control method and system for the grid-connected energy storage inverter provided by the present invention not only realizes the anti-reverse flow control of the grid-connected energy storage inverter by acquiring the current information of the load in real time and combining the power control and current control schemes, but also has higher reliability and better accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the anti-reverse flow technology principle of the existing grid-connected energy storage converter.

[0042] Figure 2 Schematic diagram of the power closed-loop control strategy of the existing grid-connected energy storage converter.

[0043] Figure 3 The figure is a schematic diagram of the method flow of the present invention.

[0044] Figure 4 Schematic diagram of the device of the method of the present invention.

[0045] Figure 5 It is a control flow diagram of the power outer loop control in the method of the present invention.

[0046] Figure 6 It is a control flow diagram of the current inner loop control in the method of the present invention.

[0047] Figure 7 Schematic diagram of the functional modules of the system of the present invention. DETAILED DESCRIPTION

[0048] like Figure 3 The method flow diagram of the method of the present invention is shown as follows: the anti-reverse flow control method of the grid-connected energy storage converter disclosed in the present invention comprises the following steps:

[0049] S1. Set up a real-time current sampling device at the total load outlet, such as Figure 4 As shown;

[0050] S2 real-time acquisition of power detection device power measurement results, and the current real-time sampling device load current sampling data;

[0051] S3. In the power outer loop control process, the filtered power value is calculated based on the power measurement result, the power set value is calculated based on the load current sampling data, and then the current set value is calculated based on the filtered power value and the power set value;

[0052] In specific implementation, the overall control process is as follows Figure 5 As shown, the specific steps include:

[0053] The filter power value is calculated based on the power measurement result, which specifically includes the following steps:

[0054] Based on the power measurement results, the PCS AC terminal voltage sampling value u S And the current sampling value i S , perform Park transformation, convert the AC quantity in the ABC three-phase coordinate system into the orthogonal component in the dq two-phase rotating coordinate system, and obtain the voltage d-axis component u Sd , voltage q-axis component u Sq , current d-axis component i Sd and the current q-axis component i Sq ;

[0055] The calculated active instantaneous power Pout is Pout = u Sd i Sd +u Sq i Sq , the reactive instantaneous power Qout is calculated to be Qout = u Sd i Sq -u Sq i Sd ;

[0056] Pout and Qout are filtered through the inertia link to obtain the active filter power value Pfil and the reactive filter power value Qfil; where the inertia link is expressed as T is the time constant of the inertia link;

[0057] The power given value is calculated based on the load current sampling data, which specifically includes the following steps:

[0058] Based on the load current sampling data, the load active current i ZP and load reactive current i ZQ Perform coordinate transformation to obtain the load d-axis current i Zd and load q-axis current i Zq ;

[0059] The calculated load active power Pload is Pload=u Sd i Zd +u Sq i Zq , the load reactive power Qload is calculated as Qload = u Sd i Zq -u Sq i Zd ;

[0060] The load active power change value ΔPload is calculated to be ΔPload=Pload'-Pload, and the load reactive power change value ΔQload is calculated to be ΔQload=Qload'-Qload; wherein Pload' is the load active power of the previous control cycle, and Qload' is the load reactive power of the previous control cycle;

[0061] The calculated active power given value Pref' is Pref'=Pref-ΔPload, and the calculated reactive power given value Pref' is Qref'=Qref-ΔQload; wherein Pref is the active power given value of the system, and Qref is the reactive power given value of the system;

[0062] The current given value is calculated based on the filtered power value and the power given value, which specifically includes the following steps:

[0063] The calculated active power change value ΔP is ΔP=Pref'-Pfil, and the calculated reactive power change value ΔQ is ΔQ=Qref'-Qfil;

[0064] The active power change value ΔP is processed by the proportional integral link and then by the limiting link to obtain the current d-axis given value Idref;

[0065] After the reactive power change value ΔQ is processed by the proportional integral link, it is limited by the limit link to obtain the current q-axis given value Iqref;

[0066] In the specific implementation process, when the system is in grid-connected steady-state operation, the Pload and Qload obtained by sampling calculation in a certain control cycle are equal to the Pload' and Qload' of the previous cycle respectively; therefore, at this time Figure 5 The ΔPload and ΔQload in the control system are both 0, and the compensation of active and reactive set values ​​is 0. The control system block diagram can be simplified as follows: Figure 2 ;

[0067] When the load in the microgrid is suddenly switched on and off, the sampled value of the load current increases, and the current value under the dq axis after coordinate transformation will also increase. The change of the load power compensation value will enter the outer loop control system as part of the given value of the PCS output power in each control cycle. At this time, the PCS output power given value is converted to Pref'=Pref-ΔPload and Qref'=Qref-ΔQload;

[0068] exist Figure 5 In the example, the Unit Delay link is a unit delay link, and its function is to obtain the Pload' and Qload' of the previous control cycle;

[0069] S4. In the current inner loop control process, based on the load current sampling data and the current given value, the three-phase modulation wave signal is calculated; the overall control process is as follows Figure 6 As shown, the specific steps include:

[0070] The d-axis component of the current i Sd The current d-axis filter component Idfil is obtained by filtering through the inertia link; the current q-axis component i Sq Through the inertia link filtering, the current q-axis filter component Iqfil is obtained;

[0071] The calculated current d-axis change ΔId is ΔId=Idref-Idfil, and the calculated current q-axis change ΔIq is ΔIq=Iqref-Iqfil;

[0072] The current d-axis change ΔId is processed through a proportional integral link to obtain the d-axis first control quantity Idc1; the current d-axis filter component Idfil is processed through a proportional link with a proportional coefficient of ωL to obtain the q-axis second control quantity Iqc2;

[0073] The current q-axis change ΔIq is processed through a proportional integral link to obtain the q-axis first control quantity Iqc1; the current q-axis filter component Iqfil is processed through a proportional link with a proportional coefficient of ωL to obtain the d-axis second control quantity Idc2;

[0074] Calculate the voltage d-axis control quantity u dfor u d =u Sd +Idc1-Idc2, calculate the voltage q-axis control value u q for u q =u Sq +Iqc1+Iqc2;

[0075] will u d and u q The voltage d-axis reference value U is obtained by performing the limiting process through the limiting link. dref and voltage q-axis reference quantity U qref ; Then U dref and U qref Through 2r / 3s transformation, we can get the A phase voltage reference U Aref , B phase voltage reference quantity U Bref and C phase voltage reference quantity U Cref ;

[0076] Will U Aref , U Bref and U Cref , as a three-phase modulated wave signal;

[0077] At this time, the active and reactive power output by the converter is equal to the value of Pref and Qref previously issued by the EMS system plus the ΔPload and ΔQload compensation caused by the load mutation; this value will quickly update the control command value, so that the power difference caused by the load power mutation can be effectively compensated by the PCS output;

[0078] S5. According to the three-phase modulation wave signal obtained in step S4, the gate control signal of the grid-connected energy storage converter is calculated, and the power electronic switch in the grid-connected energy storage converter is controlled to realize the anti-reverse flow control of the grid-connected energy storage converter; specifically comprising the following steps:

[0079] According to the three-phase modulation wave signal obtained in step S4, a PWM scheme is adopted to generate a gate control signal of the grid-connected energy storage converter, and the three-phase inverter-independent power electronic switch in the grid-connected energy storage converter is controlled.

[0080] The solution of the present invention directly samples the instantaneous change of power at the load AC end and performs feedback closed-loop control, and the dynamic response characteristics of power are greatly improved; the solution of the present invention can suppress the reverse transmission of power grid in real time to achieve "zero reverse flow".

[0081] like Figure 7The functional module schematic diagram of the system of the present invention is shown as follows: the system disclosed in the present invention for realizing the anti-backflow control method of the grid-connected energy storage converter comprises a device setting module, a data sampling module, a given value calculation module, a modulation calculation module and an anti-backflow control module; the device setting module, the data sampling module, the given value calculation module, the modulation calculation module and the anti-backflow control module are connected in series in sequence; the device setting module is used to set a current real-time sampling device at the total load outlet, and upload the data information to the data sampling module; the data sampling module is used to obtain the power measurement result of the power detection device and the load current sampling data of the current real-time sampling device in real time according to the received data information, and upload the data information to the given value calculation module; the given value calculation module is used to obtain the power measurement result of the power detection device and the load current sampling data of the current real-time sampling device .... According to the information, during the power outer loop control process, the filtered power value is calculated based on the power measurement result, the power set value is calculated based on the load current sampling data, and then the current set value is calculated based on the filtered power value and the power set value, and the data information is uploaded to the modulation calculation module; the modulation calculation module is used to calculate the three-phase modulation wave signal based on the load current sampling data and the current set value according to the received data information during the current inner loop control process, and upload the data information to the anti-reverse current control module; the anti-reverse current control module is used to calculate the gate control signal of the grid-connected energy storage inverter according to the received data information and the obtained three-phase modulation wave signal, control the power electronic switch in the grid-connected energy storage inverter, and realize the anti-reverse current control of the grid-connected energy storage inverter.

Claims

1. A method for preventing reverse flow of a grid-connected energy storage converter, comprising the following steps: S1. Set up a real-time current sampling device at the total load outlet; S2 real-time acquisition of power detection device power measurement results, and the current real-time sampling device load current sampling data; S3. In the power outer loop control process, the filtered power value is calculated based on the power measurement result, the power set value is calculated based on the load current sampling data, and then the current set value is calculated based on the filtered power value and the power set value; S4. In the current inner loop control process, based on the load current sampling data and the current given value, a three-phase modulation wave signal is calculated; S5. According to the three-phase modulation wave signal obtained in step S4, the gate control signal of the grid-connected energy storage converter is calculated, and the power electronic switch in the grid-connected energy storage converter is controlled to realize the anti-reverse flow control of the grid-connected energy storage converter.

2. The anti-backflow control method for a grid-connected energy storage converter according to claim 1, characterized in that The step S3 of calculating the filter power value based on the power measurement result specifically includes the following steps: Based on the power measurement results, the PCS AC terminal voltage sampling value u S And the current sampling value i S , perform Park transformation, convert the AC quantity in the ABC three-phase coordinate system into the orthogonal component in the dq two-phase rotating coordinate system, and obtain the voltage d-axis component u Sd , voltage q-axis component u Sq , current d-axis component i Sd and the current q-axis component i Sq ; The calculated active instantaneous power Pout is Pout = u Sd i Sd +u Sq i Sq , the reactive instantaneous power Qout is calculated to be Qout = u Sd i Sq -u Sq i Sd ; Pout and Qout are filtered through the inertia link to obtain the active filter power value Pfil and the reactive filter power value Qfil; where the inertia link is expressed as T is the time constant of the inertia link.

3. The anti-backflow control method for a grid-connected energy storage converter according to claim 2 is characterized in that The step S3 of calculating the power given value based on the load current sampling data specifically includes the following steps: Based on the load current sampling data, the load active current i ZP and load reactive current i ZQ Perform coordinate transformation to obtain the load d-axis current i Zd and load q-axis current i Zq ; The calculated load active power Pload is Pload=u Sd i Zd +u Sq i Zq , the load reactive power Qload is calculated as Qload = u Sd i Zq -u Sq i Zd ; The load active power change value ΔPload is calculated to be ΔPload=Pload'-Pload, and the load reactive power change value ΔQload is calculated to be ΔQload=Qload'-Qload; wherein Pload' is the load active power of the previous control cycle, and Qload' is the load reactive power of the previous control cycle; The calculated active power given value Pref' is Pref'=Pref-ΔPload, and the calculated reactive power given value Pref' is Qref'=Qref-ΔQload; wherein Pref is the active power given value of the system, and Qref is the reactive power given value of the system.

4. The anti-backflow control method for a grid-connected energy storage converter according to claim 3 is characterized in that The step S3 of calculating the current given value according to the filtered power value and the power given value specifically includes the following steps: The calculated active power change value ΔP is ΔP=Pref'-Pfil, and the calculated reactive power change value ΔQ is ΔQ=Qref'-Qfil; The active power change value ΔP is processed by the proportional integral link and then by the limiting link to obtain the current d-axis given value Idref; The reactive power change value ΔQ is processed by the proportional integral link and then by the limiting link to obtain the current q-axis given value Iqref.

5. The anti-backflow control method for a grid-connected energy storage converter according to claim 4 is characterized in that The step S4 of calculating the three-phase modulation wave signal based on the load current sampling data and the current given value specifically includes the following steps: The d-axis component of the current i Sd The current d-axis filter component Idfil is obtained by filtering through the inertia link; the current q-axis component i Sq Through the inertia link filtering, the current q-axis filter component Iqfil is obtained; The calculated current d-axis change ΔId is ΔId=Idref-Idfil, and the calculated current q-axis change ΔIq is ΔIq=Iqref-Iqfil; The current d-axis change ΔId is processed through a proportional integral link to obtain the d-axis first control quantity Idc1; the current d-axis filter component Idfil is processed through a proportional link with a proportional coefficient of ωL to obtain the q-axis second control quantity Iqc2; The current q-axis change ΔIq is processed through a proportional integral link to obtain the q-axis first control quantity Iqc1; the current q-axis filter component Iqfil is processed through a proportional link with a proportional coefficient of ωL to obtain the d-axis second control quantity Idc2; Calculate the voltage d-axis control quantity u d for u d =u Sd +Idc1-Idc2, calculate the voltage q-axis control value u q for u q =u Sq +Iqc1+Iqc2; will u d and u q The voltage d-axis reference value U is obtained by performing the limiting process through the limiting link. dref and voltage q-axis reference quantity U qref ; Then U dref and U qref Through 2r / 3s transformation, we can get the A phase voltage reference U Aref , B phase voltage reference quantity U Bref and C phase voltage reference quantity U Cref ; Will U Aref , U Bref and U Cref , as a three-phase modulated wave signal.

6. The anti-backflow control method for a grid-connected energy storage converter according to claim 5, characterized in that Step S5, according to the three-phase modulation wave signal obtained in step S4, calculates the gate control signal of the grid-connected energy storage converter to control the power electronic switch in the grid-connected energy storage converter, specifically includes the following steps: According to the three-phase modulation wave signal obtained in step S4, a PWM scheme is adopted to generate a gate control signal of the grid-connected energy storage converter, and the three-phase inverter-independent power electronic switch in the grid-connected energy storage converter is controlled.

7. A system for implementing the anti-backflow control method of a grid-connected energy storage converter according to any one of claims 1 to 6, characterized in that It includes a device setting module, a data sampling module, a given value calculation module, a modulation calculation module and an anti-backflow control module; the device setting module, the data sampling module, the given value calculation module, the modulation calculation module and the anti-backflow control module are connected in series in sequence; the device setting module is used to set a current real-time sampling device at the total load outlet, and upload data information to the data sampling module; The data sampling module is used to obtain the power measurement result of the power detection device and the load current sampling data of the current real-time sampling device in real time according to the received data information, and upload the data information to the given value calculation module; The given value calculation module is used to calculate the filtered power value based on the power measurement result, calculate the power given value based on the load current sampling data, and then calculate the current given value based on the filtered power value and the power given value according to the received data information, and upload the data information to the modulation calculation module; The modulation calculation module is used to calculate the three-phase modulation wave signal based on the received data information and the load current sampling data and the current given value during the current inner loop control process, and upload the data information to the anti-backflow control module; The anti-reverse flow control module is used to calculate the gate control signal of the grid-connected energy storage converter according to the received data information and the obtained three-phase modulation wave signal, control the power electronic switch in the grid-connected energy storage converter, and realize the anti-reverse flow control of the grid-connected energy storage converter.

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