A control device based on off-grid synchronous switching of multiple energy storage converters

Abstract

The present invention relates to a control device based on off-grid synchronous switching of multiple energy storage converters, and its technical characteristics are: the main control board includes an FPGA controller and a phase angle output unit, an enable output unit, and a control signal input circuit, the FPGA controller is connected to the control signal input circuit to obtain a grid phase angle signal, a grid amplitude signal, and an off-grid enable signal, the FPGA controller is connected to the phase angle output unit and outputs multiple off-grid phase angle synchronization signals, the FPGA controller is connected to the enable output unit and outputs multiple off-grid enable signals, and the multiple off-grid phase angle synchronization signals and the multiple off-grid enable signals are connected to the input ends of multiple energy storage converters to realize the off-grid synchronous switching control function of multiple energy storage converters. The present invention is reasonably designed, improves the stability of the grid when the energy storage converter switches from grid-connected operation to off-grid operation, and can provide load power supply seamlessly and quickly, without causing power outages to affect the normal operation of the load, and has the characteristics of high real-time performance and reliable performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage converters, and in particular to a control device based on off-grid synchronous switching of multiple energy storage converters. Background Art

[0002] At present, energy storage converters (Power Conversion System - PCS) are widely used in power grid operation. PCS can control the charging and discharging process of batteries, perform AC / DC conversion, and directly supply power to AC loads without power grid. PCS consists of DC / AC bidirectional converter, control unit, etc. PCS controller receives background control instructions through communication, controls the converter to charge or discharge the battery according to the sign and size of the power instruction, and realizes the regulation of active power and reactive power of the power grid.

[0003] The existing off-grid synchronous switching methods and devices for energy storage converters can usually only realize the simultaneous off-grid operation of one or two or several energy storage converters, but cannot realize the simultaneous off-grid operation of dozens or even hundreds of energy storage converters. It is even more difficult to realize the stable establishment of large-scale MW-level and tens of MW-level off-grid power grids and the uninterrupted power supply function of loads. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to propose a control device based on off-grid synchronous switching of multiple energy storage converters, which can enable all energy storage converters to enter off-grid operation state at the same time, ensure the stability of the power grid, and prevent power outages on the load.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] A control device based on off-grid synchronous switching of multiple energy storage converters comprises a main control board and a power supply circuit for powering the main control board, wherein the main control board comprises an FPGA controller and a phase angle output unit, an enable output unit and a control signal input circuit, wherein the FPGA controller is connected to the control signal input circuit to obtain a grid phase angle signal, a grid amplitude signal and an off-grid enable signal, wherein the FPGA controller is connected to the phase angle output unit and outputs multiple off-grid phase angle synchronization signals, wherein the FPGA controller is connected to the enable output unit and outputs multiple off-grid enable signals, wherein the multiple off-grid phase angle synchronization signals and the multiple off-grid enable signals are connected to the input ends of multiple energy storage converters to realize the off-grid synchronous switching control function of the multiple energy storage converters.

[0007] The phase angle output unit includes a comparator A1, a counter A2, a comparator A3, a comparator A4, a monostable register A5, a switching logic module A6 and a comparator A7; the two input ports of the comparator A1 are respectively connected to the parameter K1 and the output port of the counter A2, and the output port of the comparator A1 is connected to the reset port of the counter A2; the preset number port of the counter A2 is connected to the grid phase angle signal, the set number enable port of the counter A2 is connected to the off-grid enable signal, the clock port of the counter A2 is connected to the 40MHz clock, and the output port of the A2 counter is respectively connected to an input port of the comparator A1 and an input port of the comparator A3. , the other input end of the comparator A3 is connected to the parameter K2; the two input ports of the comparator A4 are respectively connected to the grid phase angle signal and the parameter K3, and the output end of the comparator A4 is connected to the input end of the monostable register A5; the two input ends of the switching logic module A6 are respectively connected to the grid amplitude signal and the off-grid enable signal, the output end of the switching logic module A6, the output end of the monostable register A5 and the output end of the comparator A3 are respectively connected to the input end of the comparator A7, and the output end of the comparator A7 outputs the off-grid phase angle synchronization signal; the parameter K1 is the grid period, the pulse width of the high level of the parameter K2, and the parameter K3 is the minimum detection value when the grid phase angle is zero.

[0008] The switching logic module A6 includes a comparator A9, a falling edge delay device A10, a NOT gate A11, an AND gate A12, a rising edge delay device A13, a NOT gate A14, a comparator A15, an AND gate A16, an OR gate A17 and an RS register A18; the two input ends of the comparator A9 are respectively connected to the grid amplitude signal and the parameter K4; the input end of the falling edge delay device A10 is connected to the off-grid enable signal, the output end of the falling edge delay device A10 is connected to the input end of the NOT gate A11, the output end of the NOT gate A11 and the output end of the comparator A9 are respectively connected to the two input ends of the AND gate A12, and the output end of the AND gate A12 is connected to the S input end of the RS register A18; the input end of the rising edge delay device A13 is connected to the off-grid enable signal, the The output end of the rising edge delay device A13 is connected to an input end of the OR gate A17; the input end of the NOT gate A14 is connected to the off-grid enable signal, and the output end of the NOT gate A14 is connected to an input end of the AND gate A16; the two input ends of the comparator A15 are respectively connected to the grid amplitude signal and the parameter K5, and the output end of the comparator A15 is connected to the other input end of the AND gate A16; the output end of the AND gate A16 and the output end of the rising edge delay device A13 are respectively connected to the two input ends of the OR gate A17, the output end of the OR gate A17 is connected to the R input end of the RS register A18, and the output end of the RS register A18 outputs a switching signal; the parameter K4 is the minimum AC voltage for normal operation of the energy storage converter, and the parameter K5 is the coefficient for judging that there is no electricity in the grid.

[0009] The enable output unit includes an average value calculation circuit, a logic operation circuit, a DP protocol analysis circuit, a signal processing circuit and an OR gate; the input end of the average value calculation circuit is connected to the control signal input circuit and calculates the average value of the collected external three-phase voltage signal, and the calculation result is output to the logic operation circuit; the DP protocol analysis circuit is connected to the control signal input circuit and analyzes the external DP data; the signal processing circuit is connected to the control signal input circuit and receives the high-voltage cabinet switch disconnection signal; the output end of the logic operation circuit, the output end of the protocol analysis circuit and the output of the signal processing circuit are respectively connected to the input end of the OR gate, and the OR gate outputs an off-grid enable signal.

[0010] The control signal input circuit includes a DP port circuit, a voltage sampling circuit and an AD conversion circuit, an I / O port circuit, and an optical fiber input port. The DP port circuit is connected to a DP device and transmits the received DP data to an enable output unit. The voltage sampling circuit is connected to an external grid voltage and transmits an external voltage signal to the enable output unit through an AD conversion circuit. The I / O port circuit is connected to a high-voltage cabinet and transmits a switch disconnection signal to the enable output unit. The optical fiber input port is connected to a grid phase angle signal and an off-grid enable signal.

[0011] The power supply circuit includes two switching power supplies, two switches and two indicator lights. The two switching power supplies are respectively connected to an external power supply through a switch. The output ends of the two switching power supplies are connected to a main control board to supply power thereto. The two indicator lights are respectively connected to the output ends of the two switching power supplies to indicate the status of the switching power supplies.

[0012] The external power supply is 220V AC or 220V DC, and the switching power supply is 15V DC.

[0013] The phase angle output unit includes 12 off-grid phase angle synchronization signal output ports, and the enable output unit includes 12 off-grid enable signal output ports.

[0014] One off-grid phase angle synchronization signal output by the phase angle output unit and one off-grid enable signal output by the enable output unit are connected to another control mainboard input terminal to realize the cascade function of multiple control devices.

[0015] The advantages and positive effects of the present invention are:

[0016] 1. The present invention enables the energy storage inverter to establish the same off-grid voltage by generating an off-grid synchronous phase angle signal and an off-grid enable signal, ensuring that the grid phase and frequency of all energy storage inverters are exactly the same, and all energy storage inverters can enter the off-grid operation state at the same time, ensuring the stability of the grid and the load will not be powered off. At the same time, there will be no grid oscillation caused by each energy storage inverter performing its own frequency regulation, and there will be no grid collapse due to excessive load on a single machine due to the inability to switch off the grid at the same time. The present invention improves the stability of the grid when the energy storage inverter switches from grid-connected operation to off-grid operation, and can provide load power supply seamlessly and quickly, without causing power outages and affecting the normal operation of the load.

[0017] 2. The controller of the present invention adopts FPGA as the core control component, which has high real-time performance and reliable performance. All output signal delays are consistent, and the error is at the nanosecond level, ensuring the consistency of the signals received by the energy storage converter.

[0018] 3. The present invention can be cascaded and control hundreds of energy storage converters, thereby realizing the off-grid synchronous switching function of more energy storage converters. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a connection diagram of the control device of the present invention;

[0020] Figure 2 It is a circuit schematic diagram of the main control board of the present invention;

[0021] Figure 3 is a circuit block diagram of a phase angle output unit of the present invention;

[0022] Figure 4 is a block diagram of a switching logic function module of the present invention;

[0023] Figure 5 It is a waveform diagram of the phase angle synchronization signal generated by the present invention;

[0024] Figure 6 is a circuit block diagram of an enable output unit of the present invention;

[0025] Figure 7 It is a schematic diagram of the extended connection of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to the accompanying drawings.

[0027] A control device based on off-grid synchronous switching of multiple energy storage converters, such as Figure 1As shown, it includes a main control board and a power supply circuit for powering it, the power supply circuit includes two switching power supplies, two switches and two indicator lights, the two switching power supplies are respectively connected to an external power supply through a switch, the external power supply can use 220V AC or 220V DC, the two switching power supplies both have 15V power output and the output ends are connected to the main control board, and the two indicator lights are respectively connected to the output ends of the two switching power supplies to indicate the status of the switching power supplies.

[0028] The main control board uses FPGA as the core to realize the off-grid synchronous switching control function of multiple energy storage converters. Figure 2 As shown, the main control board includes an FPGA controller and a phase angle output unit, an enable output unit, a DP port circuit, a voltage sampling circuit, an I / O port circuit and an optical fiber input port connected thereto. The DP port circuit, the voltage sampling circuit, the I / O port circuit and the optical fiber input port constitute a control signal input circuit connected to the FPGA controller. The phase angle output unit includes 12 optical fiber output ports, and the enable output unit includes 12 optical fiber output ports. The FPGA controller is connected to the phase angle output unit to realize a 12-way phase angle signal output function, and the FPGA controller is connected to the enable output unit to realize a 12-way enable signal output function. Each phase angle output port and the enable output port are connected to the corresponding input port of one energy storage inverter, thereby realizing the off-grid synchronous switching function of multiple energy storage inverters.

[0029] The phase angle output unit generates an off-grid phase angle synchronization signal under the control of the FPGA controller. Figure 3 As shown, the phase angle output unit includes a comparator A1, a counter A2, a comparator A3, a comparator A4, a monostable register A5, a switching logic module A6 and a comparator A7. The two input ports of the comparator A1 are respectively connected to the parameter K1 and the output port of the counter A2, and the output port of the comparator A1 is connected to the reset port of the counter A2; the preset number port of the counter A2 is connected to the grid phase angle signal, the set number enable port of the counter A2 is connected to the off-grid enable signal, the clock port of the counter A2 is connected to the 40MHz clock, the output port of the A2 counter is respectively connected to an input port of the comparator A1 and an input port of the comparator A3, and the other input end of the comparator A3 is connected to the parameter K2; the two input ports of the comparator A4 are respectively connected to the grid phase angle signal and the parameter K3, and the output end of the comparator A4 is connected to the input end of the monostable register A5; the two input ends of the switching logic module A6 are respectively connected to the grid amplitude signal and the off-grid enable signal, the output end of the switching logic module A6, the output end of the monostable register A5 and the output end of the comparator A3 are respectively connected to the input end of the comparator A7, and the output end of the comparator A7 outputs the off-grid phase angle synchronization signal.

[0030] like Figure 4 As shown, the switching logic module A6 includes a comparator A9, a falling edge delay device A10, a NOT gate A11, an AND gate A12, a rising edge delay device A13, a NOT gate A14, a comparator A15, an AND gate A16, an OR gate A17, and an RS register A18. The two input terminals of the comparator A9 are respectively connected to the grid amplitude signal and the parameter K4; the input terminal of the falling edge delay device A10 is connected to the off-grid enable signal, the output terminal of the falling edge delay device A10 is connected to the NOT gate A11, the output terminal of the NOT gate A11 and the output terminal of the comparator A9 are respectively connected to the two input terminals of the AND gate A12, and the output terminal of the AND gate A12 is connected to the S input terminal of the RS register A18; the input terminal of the rising edge delay device A13 is connected to the off-grid enable signal, and the output terminal of the rising edge delay device A13 is connected to an input terminal of the OR gate A17. connection; the input end of the NOT gate A14 is connected to the off-grid enable signal, and the output end of the NOT gate A14 is connected to an input end of the AND gate A16; the two input ends of the comparator A15 are respectively connected to the grid amplitude signal and the parameter K5, and the output end of the comparator A15 is connected to the other input end of the AND gate A16; the output end of the AND gate A16 and the output end of the rising edge delay device A13 are respectively connected to the two input ends of the OR gate A17, and the output end of the OR gate A17 is connected to the R input end of the RS register A18, and the output end of the RS register A18 outputs the switching signal Q.

[0031] In this embodiment, parameter K1 is set to the period of the corresponding power grid (for a power grid with a frequency of 50 Hz, the period of the power grid is 20 ms, then K1 is set to 800000), parameter K2 is the pulse width corresponding to the high level, parameter K3 is the minimum detection value when the power grid phase angle is zero. Parameter K4 is the minimum AC voltage for the normal operation of the energy storage converter, and parameter K5 is the coefficient for judging that there is no power in the power grid.

[0032] The process of the FPGA controller controlling the phase angle output unit to generate the off-grid phase angle synchronization signal is as follows:

[0033] In comparator A1, when the output value of counter A2 is greater than K1, counter A2 is reset, starts counting from 0, and counts cyclically to generate a phase angle signal with a fixed grid frequency. The rising edge of the off-grid enable signal can set the counter A2, and the grid phase angle is placed in counter A2. Then counter A2 starts counting from the current grid phase angle, and the output phase angle realizes tracking the grid phase angle. When the output value of counter A2 is less than parameter K2, comparator A3 outputs a high level, and comparator A3 outputs a synchronous phase angle signal with a fixed grid frequency; comparator A4 and monostable register A5 generate a phase angle synchronization signal according to the actual grid phase angle. Comparator A4 compares the grid phase angle with parameter K3 to determine the zero crossing position of the actual grid phase angle, and monostable register A5 generates a high level signal of parameter T1 time, which is the synchronization signal of the actual grid phase angle.

[0034] The switching logic module A6 generates the switching logic according to the grid amplitude and the off-grid enable signal, which is used to realize the switching between the actual grid phase angle and the fixed grid phase angle. The off-grid phase angle synchronization signal generated by the switching logic module A6 logic selection includes the following 4 cases:

[0035] ⑴. The energy storage converter operates in the grid-connected state, there is no off-grid enable signal, the phase angle synchronization signal is generated by the actual grid phase angle, the comparator A9 compares the grid amplitude to be greater than the parameter K4, and the off-grid enable signal is 0, the RS register A18 is set to 1, and the output switching signal is 1.

[0036] ⑵. The energy storage converter switches from grid-connected to off-grid operation and generates an off-grid enable signal. After the rising edge delay A13 passes the parameter T3 (T3 can be less than the grid cycle 20ms), the output of the OR gate A17 is 1, the RS register A10 is set to 0, the output switching signal becomes 0, and the phase angle synchronization signal becomes a fixed grid phase angle.

[0037] ⑶. The energy storage converter switches from off-grid to grid-connected operation, the off-grid enable signal is cleared, and after the falling edge delay A10 passes the parameter T2 (T2 can be set according to the time of switching from off-grid to grid-connected), the output of AND gate A12 is 1, the RS register A18 is set to 1, and the phase angle synchronization signal is generated by the actual grid phase angle.

[0038] (4) When the energy storage converter operates without a power grid and needs to start off-grid operation, the comparator A15 compares the grid amplitude which is less than the parameter K5, and there is no off-grid enable signal. The AND gate A16 outputs 1, and the RS register A18 is set to 0, 0. The phase angle synchronization signal is changed to a fixed grid phase angle.

[0039] The phase angle synchronization signal selected by the switching logic module is then output to the 12-way optical fiber port of the phase angle output unit through the corresponding pins of the FPGA controller, and reaches the energy storage converter through the optical fiber connected to the energy storage converter. Since the FPGA controller has parallel output capability, the output signal consistency can be guaranteed, and the synchronization time error is at the nanosecond level, which is much smaller than the control cycle of the energy storage converter, and will not cause output voltage frequency differences.

[0040] The off-grid phase angle synchronization signal output by the control device is output to the energy storage converter, and the energy storage converter receives the phase angle synchronization signal and generates its own off-grid phase angle. Figure 5 As shown, each energy storage converter receives a phase angle synchronization signal, and generates a phase angle corresponding to the grid frequency through its controller, where the phase angle is 0 to 16383 and corresponds to 0 to 2π, and the phase angle of the off-grid voltage is calculated. Each energy storage converter generates a corresponding off-grid voltage according to the off-grid phase angle. Since each energy storage converter receives exactly the same phase angle synchronization signal, the generated electrical angle is also exactly the same, and the calculated off-grid voltage phase angle must also be consistent. Therefore, all energy storage converters that receive phase angle synchronization generate the same off-grid voltage, which meets the requirements of large-scale off-grid operation.

[0041] like Figure 6 As shown, the enable output unit includes an average value calculation circuit, a logic operation circuit, a DP protocol analysis circuit, a signal processing circuit and an OR gate. The input end of the average value calculation circuit is connected to the voltage sampling circuit through an AD conversion circuit, and the voltage sampling circuit is connected to the external power grid voltage to collect the three-phase voltages UA, UB, and UC. The output end of the average value calculation circuit is connected to the logic operation circuit; the DP protocol analysis circuit receives external DP data through the DP port circuit and analyzes the DP data; the signal processing circuit receives the high-voltage cabinet switch disconnection signal through the I / O port circuit; the output end of the logic operation circuit, the output end of the protocol analysis circuit and the output of the signal processing circuit are respectively connected to the input end of the OR gate, and the OR gate outputs an off-grid enable signal. There are the following three off-grid enable signals for users to enable the energy storage converter off-grid:

[0042] ⑴. Collect the grid voltage signal, pass through the sampling circuit and AD conversion circuit on the main control board, and then enter the FPGA average calculation circuit, and then the off-grid enable signal is output through the logic operation of the FPGA controller;

[0043] ⑵, receive the off-grid enable signal sent by the host computer through the DP port circuit (Profibus-DP port), and parse the signal through the DP protocol circuit of the FPGA controller;

[0044] ⑶. Use the I / O port circuit to collect the signal of the high-voltage cabinet switch being disconnected, and output the off-grid enable signal after being processed by the signal processing circuit of the FPGA controller.

[0045] The OR gate of the enable output unit performs OR logic operation on the three signals. As long as one of the signals becomes a high level, the optical fiber output port of the corresponding enable output unit sends a signal to the energy storage inverter, and all energy storage inverters that receive the off-grid enable signal enter the off-grid operation state at the same time.

[0046] A control device provided by the present invention can realize the off-grid synchronous switching function of 12 energy storage inverters. Since FPGA has parallel output capability, the synchronization time error is at the nanosecond level, which is much smaller than the control cycle of the energy storage inverter and will not cause output voltage frequency differences. The phase angle synchronization signals received by each energy storage inverter are exactly the same, and the generated electrical angles are also exactly the same. The calculated off-grid voltage phase angles are consistent. Therefore, the present invention can be extended and connected to realize the off-grid synchronous switching function of more energy storage inverters. Figure 7 As shown in the figure, one output port of the phase angle signal output unit and one output of the enable output unit of a main control board are connected to the optical fiber input port of the next-level main control board, so that the two control devices have a total of 23 phase angle synchronization signals and 23 off-grid enable signals. More devices can be expanded in this way, reaching hundreds of output ports. Among them, the calculation formula for the number of energy storage converters corresponding to each group of ports is:

[0047] P=12+(n-1)×11

[0048] Wherein, P is the number of output ports and n is the number of control devices.

[0049] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific implementation manner. Any other implementation manners derived by those skilled in the art based on the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A control device based on off-grid synchronous switching of multiple energy storage converters, comprising a main control board and a power supply circuit for powering the main control board, characterized in that: The main control board includes an FPGA controller and a phase angle output unit, an enable output unit, and a control signal input circuit. The FPGA controller is connected to the control signal input circuit to obtain a grid phase angle signal, a grid amplitude signal, and an off-grid enable signal. The FPGA controller is connected to the phase angle output unit and outputs a multi-channel off-grid phase angle synchronization signal. The FPGA controller is connected to the enable output unit and outputs a multi-channel off-grid enable signal. The multi-channel off-grid phase angle synchronization signal and the multi-channel off-grid enable signal are connected to the input end of multiple energy storage converters to realize the off-grid synchronous switching control function of multiple energy storage converters. The phase angle output unit includes a comparator A1, a counter A2, a comparator A3, a comparator A4, a monostable register A5, a switching logic module A6 and a comparator A7; the two input ports of the comparator A1 are respectively connected to the parameter K1 and the output port of the counter A2, and the output port of the comparator A1 is connected to the reset port of the counter A2; the preset number port of the counter A2 is connected to the grid phase angle signal, the set number enable port of the counter A2 is connected to the off-grid enable signal, the clock port of the counter A2 is connected to the 40MHz clock, and the output port of the A2 counter is respectively connected to an input port of the comparator A1 and an input port of the comparator A3. , the other input end of the comparator A3 is connected to the parameter K2; the two input ports of the comparator A4 are respectively connected to the grid phase angle signal and the parameter K3, and the output end of the comparator A4 is connected to the input end of the monostable register A5; the two input ends of the switching logic module A6 are respectively connected to the grid amplitude signal and the off-grid enable signal, the output end of the switching logic module A6, the output end of the monostable register A5 and the output end of the comparator A3 are respectively connected to the input end of the comparator A7, and the output end of the comparator A7 outputs the off-grid phase angle synchronization signal; the parameter K1 is the grid period, the pulse width of the high level of the parameter K2, and the parameter K3 is the minimum detection value when the grid phase angle is zero; The switching logic module A6 includes a comparator A9, a falling edge delay device A10, a NOT gate A11, an AND gate A12, a rising edge delay device A13, a NOT gate A14, a comparator A15, an AND gate A16, an OR gate A17 and an RS register A18; the two input ends of the comparator A9 are respectively connected to the grid amplitude signal and the parameter K4; the input end of the falling edge delay device A10 is connected to the off-grid enable signal, the output end of the falling edge delay device A10 is connected to the input end of the NOT gate A11, the output end of the NOT gate A11 and the output end of the comparator A9 are respectively connected to the two input ends of the AND gate A12, and the output end of the AND gate A12 is connected to the S input end of the RS register A18; the input end of the rising edge delay device A13 is connected to the off-grid enable signal, the The output end of the rising edge delay device A13 is connected to an input end of the OR gate A17; the input end of the NOT gate A14 is connected to the off-grid enable signal, and the output end of the NOT gate A14 is connected to an input end of the AND gate A16; the two input ends of the comparator A15 are respectively connected to the grid amplitude signal and the parameter K5, and the output end of the comparator A15 is connected to the other input end of the AND gate A16; the output end of the AND gate A16 and the output end of the rising edge delay device A13 are respectively connected to the two input ends of the OR gate A17, and the output end of the OR gate A17 is connected to the R input end of the RS register A18, and the output end of the RS register A18 outputs a switching signal; the parameter K4 is the minimum AC voltage for the normal operation of the energy storage converter, and the parameter K5 is a coefficient for judging that there is no electricity in the grid; The enable output unit includes an average value calculation circuit, a logic operation circuit, a DP protocol analysis circuit, a signal processing circuit and an OR gate; the input end of the average value calculation circuit is connected to the control signal input circuit and calculates the average value of the collected external three-phase voltage signal, and the calculation result is output to the logic operation circuit; the DP protocol analysis circuit is connected to the control signal input circuit and analyzes the external DP data; the signal processing circuit is connected to the control signal input circuit and receives the high-voltage cabinet switch disconnection signal; the output end of the logic operation circuit, the output end of the protocol analysis circuit and the output of the signal processing circuit are respectively connected to the input end of the OR gate, and the OR gate outputs an off-grid enable signal; The phase angle output unit generates an off-grid phase angle synchronization signal under the control of the FPGA controller; The switching logic module A6 generates a switching logic according to the grid amplitude and the off-grid enable signal, and is used to realize the switching between the actual grid phase angle and the fixed grid phase angle; The OR gate of the enable output unit performs OR logic operation on the three signals. As long as one of the signals becomes a high level, the optical fiber output port of the corresponding enable output unit sends a signal to the energy storage inverter, and all energy storage inverters that receive the off-grid enable signal enter the off-grid operation state at the same time.

2. A control device based on off-grid synchronous switching of multiple energy storage converters according to claim 1, characterized in that: The control signal input circuit includes a DP port circuit, a voltage sampling circuit and an AD conversion circuit, an I / O port circuit, and an optical fiber input port. The DP port circuit is connected to a DP device and transmits the received DP data to an enable output unit. The voltage sampling circuit is connected to an external grid voltage and transmits an external voltage signal to the enable output unit through an AD conversion circuit. The I / O port circuit is connected to a high-voltage cabinet and transmits a switch disconnection signal to the enable output unit. The optical fiber input port is connected to a grid phase angle signal and an off-grid enable signal.

3. A control device based on off-grid synchronous switching of multiple energy storage converters according to claim 1, characterized in that: The power supply circuit includes two switching power supplies, two switches and two indicator lights. The two switching power supplies are respectively connected to an external power supply through a switch. The output ends of the two switching power supplies are connected to a main control board to supply power thereto. The two indicator lights are respectively connected to the output ends of the two switching power supplies to indicate the status of the switching power supplies.

4. A control device based on off-grid synchronous switching of multiple energy storage converters according to claim 3, characterized in that: The external power supply is 220V AC or 220V DC, and the switching power supply is 15V DC.

5. A control device based on off-grid synchronous switching of multiple energy storage converters according to claim 1, characterized in that: The phase angle output unit includes 12 off-grid phase angle synchronization signal output ports, and the enable output unit includes 12 off-grid enable signal output ports.

6. A control device based on off-grid synchronous switching of multiple energy storage converters according to claim 1, characterized in that: One off-grid phase angle synchronization signal output by the phase angle output unit and one off-grid enable signal output by the enable output unit are connected to another control mainboard input terminal to realize the cascade function of multiple control devices.

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