Energy storage power supply vehicle grid-connected and off-grid control method and device and energy storage power supply vehicle

Abstract

The invention discloses a grid-connected and off-grid control method and device for an energy storage power supply vehicle and the energy storage power supply vehicle. The following delays of the energy storage power supply vehicle in the grid-connected and off-grid switching process are synchronously estimated by triggering an independent pulse signal: grid voltage sampling delay: cooperative calculation based on the analog-to-digital conversion time difference and the signal transmission time difference of a parallel operation side and a grid connection side; instruction transmission delay: performing dynamic accumulation calculation on the processing time of a processor between the controllers and the signal transmission time; closing action time delay: calculating by combining the processing time of the grid-connected controller and the inherent action time of the circuit breaker; calculating a phase difference in real time based on the total delay, and dynamically adjusting the phase angle of the grid-connected voltage output by the energy storage power supply vehicle by superposing a preset phase difference; through a double-loop PI control strategy of a power electronic converter, a grid-connected inverter is adjusted to output a phase angle after dynamic adjustment so as to realize low-impact flexible grid connection of the energy storage power supply vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage power supply vehicles, and in particular to a method and device for controlling grid connection and disconnection of an energy storage power supply vehicle, and an energy storage power supply vehicle. Background Art

[0002] With the continuous expansion of investment in power construction and the continuous improvement of power supply requirements, the market demand for mobile energy storage power supply vehicles is growing. Energy storage power supply vehicles can be used for upgrading and transformation of power systems, large-scale shared energy storage power stations on the grid side, dispatching peak-shaving power stations, providing power supply guarantees during emergency rescue and disaster relief, and supplying power to important loads. They are widely used in all links of the power system power supply side, grid side, and user side.

[0003] However, connecting energy storage power supply vehicles to the grid will also have an impact on their stable operation, which is also one of the factors restricting the expansion of the energy storage power supply vehicle market. It is necessary to improve the on-grid and off-grid control technology of energy storage power supply vehicles.

[0004] Regarding the grid-connection and off-grid control methods for energy storage power supply vehicles, current grid-connection control methods often use synchronous grid-connection status detection to collect various grid-connection parameters of the power supply vehicle in real time. After analyzing these parameters, a real-time judgment of the synchronous grid-connection status is made, which serves as the data basis for grid-connection control. However, since the power supply vehicle supplies power to the grid system continuously and uninterruptedly, the real-time data detection and analysis method can only analyze and judge the grid-connection status collected at the current moment. It cannot solve the delay issues that occur during the data collection process, command transmission, and closing process. As a result, the phase angle difference of the voltage of the energy storage power supply vehicle is always present when it is connected to the grid, and current surges occur during the grid connection process, affecting the normal operation of the grid side. Summary of the Invention

[0005] In response to the defects and shortcomings of the existing technology, the present invention provides a method and device for controlling the on-grid and off-grid connection of an energy storage power supply vehicle, as well as an energy storage power supply vehicle. By triggering a separate pulse signal, the grid voltage sampling delay, the instruction transmission delay between controllers and the closing action delay on the parallel side and the grid side are synchronously estimated. The phase difference is dynamically calculated based on the total delay and the preset phase difference is superimposed to adapt to different grid scenarios. The voltage amplitude and phase angle output by the grid-connected inverter are adjusted in real time in combination with the dual-loop PI control strategy to achieve low-impact flexible grid connection of the energy storage power supply vehicle. At the same time, through the collaborative judgment mechanism of the preset voltage difference threshold, frequency difference threshold and dynamic off-grid threshold, the senseless transition of the on-grid and off-grid switching process and the stable operation of the grid are ensured, solving the problems of phase angle deviation, current impact and insufficient scenario adaptation caused by the superposition of multi-link delays.

[0006] The present invention specifically adopts the following technical solutions:

[0007] A method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle:

[0008] By triggering a separate pulse signal, the following delays in the energy storage power supply vehicle's on-grid and off-grid switching process are estimated synchronously:

[0009] Grid voltage sampling delay: This is calculated based on the analog-to-digital conversion time difference and signal transmission time difference between the parallel generator side and the grid side;

[0010] Instruction transmission delay: calculated by dynamically accumulating the processor processing time and signal transmission time between controllers;

[0011] Closing action delay: calculated by combining the grid controller processing time and the circuit breaker inherent action time;

[0012] The phase difference is calculated in real time based on the total delay, and the phase angle of the grid-connected voltage output by the energy storage power supply vehicle is dynamically adjusted by superimposing the preset phase difference;

[0013] Through the dual-loop PI control strategy of the power electronic converter, the dynamically adjusted phase angle of the grid-connected inverter output is adjusted to achieve low-impact flexible grid connection of the energy storage power supply vehicle.

[0014] Furthermore, the grid voltage sampling delay is calculated by collaboratively comparing the analog-to-digital conversion and signal transmission time difference between the parallel generator side and the grid-connected side, specifically:

[0015] The signal transmission time on the parallel side is based on the number of serial communication data packets N, the number of bits M and the controller clock cycle T clk Calculate and satisfy T trans1 =N·M·T clk ;

[0016] The signal transmission time on the grid side is calculated based on the corresponding controller parameters;

[0017] The total sampling delay is calculated based on the following formula:

[0018] T delay1 =T conv1 +T trans1 -(T conv2 +T trans5 )

[0019] Among them, T delay1 is the grid voltage sampling delay, T conv1 T is the analog-to-digital conversion time of the AD chip sampling on the parallel controller side, trans1 T is the time it takes for the sampling chip signal to be transmitted to the parallel controller. conv2 T is the analog-to-digital conversion time of the sampling AD chip on the grid-connected controller side, trans5 It is the time taken for the sampling chip signal to be transmitted to the grid controller.

[0020] Furthermore, the calculation of the instruction transmission delay is achieved by synchronously measuring the processing and transmission time between controllers using a trigger pulse signal: Tdelay2 =T mcu +T trans , specifically including:

[0021] Total processor processing time T mcu The dynamic accumulation calculation is performed through the time stamp difference of the trigger pulse signal of the parallel controller, parallel coordination controller, and grid coordination controller. The formula is:

[0022] T mcu* =T end -T start

[0023] T mcu =T mcu1 +T mcu2 +T mcu3

[0024] Among them, T mcu* is the single processor delay, T end The end data processing time of a single processor, T start The start time of data processing for a single processor, T mcu is the total processor delay during the transmission process, T mcu1 T is the parallel controller processor delay during transmission. mcu2 T is the delay of the parallel coordination controller processor during the transmission process. mcu3 To coordinate the controller processor delay for the grid connection during transmission;

[0025] Total signal transmission time T trans Calculated by accumulating the data packet transmission time between controllers:

[0026] T trans* =N * ·M * ·T clk *

[0027] T trans =T trans2 +T trans3 +T trans4

[0028] Among them, T trans* is the signal transmission time between each controller, N * M is the count value of serial communication data packets by each controller, * is the number of bits contained in the corresponding data packet in each controller, T clk * is the clock period of each controller, T trans is the total signal data packet transmission delay, T trans2T is the signal transmission time between the parallel controller and the parallel coordination controller. trans3 T is the signal transmission time between the parallel coordination controller and the grid coordination controller, trans4 It is the signal transmission time between the parallel coordination controller and the grid-connected controller.

[0029] Furthermore, the calculation of the closing action delay is achieved by dynamically measuring the processing time of the grid-connected controller and combining it with the inherent action time of the circuit breaker. The formula is:

[0030] T delay2 =T mcu +T trans

[0031] Where: T delay2 is the instruction transmission delay, T mcu is the total processor delay during the transmission process, T trans is the total signal packet transmission delay.

[0032] Furthermore, the grid connection phase angle is dynamically adjusted based on the total delay, specifically including:

[0033] According to the grid voltage frequency f and the total delay ΔT, the phase difference is calculated using the formula Δθ=2πfΔT;

[0034] The grid-connected phase difference θ is preset by superimposing the real-time grid voltage phase angle φ re , dynamically adjust the phase angle φ' of the output grid-connected voltage, the formula is:

[0035] φ'=φ+Δθ+θ re

[0036] Among them, the grid voltage phase angle φ is obtained by measuring the grid connection point voltage phase in real time through the phase-locked loop technology, θ re It is the preset value adapted to the power grid scenario.

[0037] Furthermore, the control of the power electronic converter includes:

[0038] Adjust the output voltage level of the energy storage power supply vehicle through the DC converter;

[0039] Generate inverter control signals based on PWM technology;

[0040] A dual-loop PI control strategy of voltage loop and current loop is used to adjust the grid voltage amplitude and phase.

[0041] Furthermore, the triggering conditions for flexible grid connection are: when it is detected that the voltage difference across the circuit breaker is less than the preset voltage difference threshold and the frequency difference is less than the preset frequency difference threshold, the closing signal is triggered; the off-grid switching conditions are: when the grid side recovers stability and the difference between the output voltage of the energy storage power supply vehicle and the grid voltage is less than the dynamically set threshold, the opening signal is triggered.

[0042] And, a grid-connected and off-grid control device for an energy storage power supply vehicle, comprising:

[0043] The delay estimation module is used to synchronously estimate the grid voltage sampling delay, command transmission delay and closing action delay by triggering a separate pulse signal;

[0044] The phase compensation module is used to calculate the phase difference in real time based on the total delay, and dynamically adjust the phase angle of the grid-connected voltage output by the energy storage power supply vehicle by superimposing the preset phase difference;

[0045] The power electronic converter control module is used to adjust the dynamically adjusted phase angle of the grid-connected inverter output through a dual-loop PI control strategy to achieve flexible grid connection.

[0046] Furthermore, the delay estimation module includes:

[0047] A sampling delay calculation unit is configured to collaboratively compare the analog-to-digital conversion and signal transmission time difference between the parallel side and the grid side;

[0048] an instruction transmission delay calculation unit configured to dynamically accumulate processor processing time and signal transmission time between controllers;

[0049] The closing action delay calculation unit is configured to combine the processing time of the grid-connected controller and the inherent action time of the circuit breaker.

[0050] The phase compensation module includes:

[0051] Phase-locked loop unit, used for real-time measurement of grid voltage phase angle φ;

[0052] a phase difference calculation unit configured to calculate the phase difference according to the grid voltage frequency f and the total delay ΔT using a formula Δθ=2πfΔT;

[0053] A dynamic superposition unit is configured to preset a grid-connected phase difference θ by superimposing a real-time grid voltage phase angle φ re , dynamically adjust the phase angle φ' of the output grid-connected voltage, the formula is:

[0054] φ'=φ+Δθ+θ re

[0055] Among them, θ re It is the preset value adapted to the power grid scenario.

[0056] An energy storage power supply vehicle includes the above-mentioned on-grid and off-grid control device, and:

[0057] An energy storage unit, used to store electrical energy and output it to the inverter through a DC converter;

[0058] a grid-connected inverter configured to output a dynamically adjusted voltage and phase angle according to a regulation signal from the control device;

[0059] The circuit breaker is used to perform closing or opening operations when flexible grid connection or disconnection conditions are met.

[0060] And, an electronic device includes a memory, a processor, and a computer program stored in the memory and runnable on the processor, characterized in that the processor implements the steps of the above method when executing the program.

[0061] A non-transitory computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0062] Compared with the prior art, the present invention and its preferred embodiments have at least the following beneficial effects:

[0063] Through the coordinated measurement of multi-link delays and the dynamic phase angle compensation mechanism, the grid connection angle error and current impact are significantly reduced, solving the phase angle mismatch problem caused by the superposition of sampling, transmission, and action delays in traditional solutions.

[0064] An adaptive regulation strategy based on dynamic thresholds and preset phase differences takes into account the flexible grid connection requirements of different grid scenarios, improving system robustness and scenario adaptability.

[0065] The coordinated design of dual-loop PI control and power electronic converter enhances the real-time adjustment accuracy of inverter output parameters and ensures seamless transition during on-grid and off-grid switching.

[0066] It covers the complete design of methods, devices and energy storage power supply vehicles. Through the coordination of modular control devices and vehicle hardware (including energy storage units, grid-connected inverters and circuit breakers), it realizes the integrated integration of delay compensation, phase adjustment and flexible switching functions, thereby improving system deployment efficiency and operational reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0068] Figure 1 This is an overall framework diagram of the grid-connected delay generated by the energy storage power supply vehicle according to an embodiment of the present invention.

[0069] Figure 2This is a flow chart of an embodiment of the present invention for measuring three types of delays: grid voltage sampling delay, command transmission delay, and closing action delay.

[0070] Figure 3 This is a flow chart of an embodiment of the present invention for recalculating the grid-connected phase angle based on the measured grid voltage sampling delay, command transmission delay, and closing action delay.

[0071] Figure 4 This is a diagram of a flexible grid-connected control method for an energy storage power supply vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0072] Hereinafter, specific embodiments of the present application will be described in detail with reference to the accompanying drawings. Based on these detailed descriptions, those skilled in the art will be able to clearly understand the present application and implement the present application. Without violating the principles of the present application, the features of different embodiments may be combined to obtain new implementations, or certain features of certain embodiments may be substituted to obtain other preferred implementations.

[0073] To make the features and advantages of the present invention more clearly understood, the following embodiments are specifically described in detail with reference to the accompanying drawings.

[0074] In response to the shortcomings of the existing technology, the purpose of the present invention is to provide a grid-connected and off-grid control solution for energy storage power supply vehicles, which is used to solve the problem of grid-connected angle error of energy storage power supply vehicles caused by grid voltage sampling delay, command transmission delay and closing action delay, thereby reducing grid-connected current impact, realizing flexible grid connection of the equipment, and reducing the impact of the energy storage power supply vehicle on the grid during the on-grid and off-grid switching process.

[0075] To this end, embodiments of the present invention provide a method and device for controlling the on-grid and off-grid operation of an energy storage power supply vehicle, as well as an energy storage power supply vehicle. These methods address the phase angle deviation and current shock problems caused by grid voltage sampling delay, command transmission delay, and closing action delay during the on-grid and off-grid switching process of the energy storage power supply vehicle. The methods use a triggering separate pulse signal to estimate the grid voltage sampling delay, command transmission delay, and closing action delay. The phase angle used to connect the energy storage power supply vehicle to the mains grid is recalculated based on the obtained delay time. More accurate grid-connected closing signal control is achieved by utilizing a power electronic converter device.

[0076] like Figure 1 The figure shows the overall framework of the energy storage power supply vehicle delay, which is divided into three parts: grid voltage sampling delay, command transmission delay and closing action delay.

[0077] The above-mentioned on-grid and off-grid control method can significantly reduce the grid-connected angle error of the energy storage power supply vehicle, while reducing the grid-connected current impact, realizing flexible grid connection of the energy storage power supply vehicle, and reducing the impact of the energy storage power supply vehicle on the power grid during the on-grid and off-grid switching process.

[0078] like Figure 2 As shown in FIG, there are three specific flow charts for measuring grid voltage sampling delay, command transmission delay and closing action delay. Figure 2 (a) shows the sampling delay measurement, which uses the triggering of a separate pulse signal to estimate the sampling delay of the grid voltage; Figure 2 (b) shows the instruction delay measurement, which uses a trigger pulse signal to estimate the instruction transmission delay time; Figure 2 (c) shows the closing action delay measurement, which uses a trigger pulse signal to estimate the closing action delay time.

[0079] like Figure 3 As shown, the present invention addresses the current shock and phase angle deviation problems generated by the energy storage power supply vehicle during the grid connection and disconnection process. It uses a triggering separate pulse signal to estimate the grid voltage sampling delay, command transmission delay, and closing action delay. The phase angle used to connect to the mains grid is recalculated based on the obtained delay time. The delay phase difference is calculated based on the above three delay times. Taking into account the grid connection phase difference requirements, the grid connection phase angle is finally calculated.

[0080] As a preferred solution of this embodiment, the grid voltage sampling delay is estimated by triggering a separate pulse signal. Specifically, on the parallel controller side, a high sampling rate sampling device is used to capture the instantaneous change of the grid voltage, convert the analog quantity into a digital quantity, and send it to the parallel controller. This process will generate a sampling delay, including the analog-to-digital conversion time of the sampling AD chip and the time it takes for the sampling chip signal to be transmitted to the parallel controller. The analog-to-digital conversion time of the sampling AD chip is determined by the parallel side AD chip itself, and the conversion time is T conv1 After completing the analog-to-digital conversion of the grid voltage information, the sampling chip sends a signal of the grid information to the parallel controller on the energy storage power supply vehicle. At this time, a trigger pulse signal is used to estimate the signal transmission delay. Specifically, the parallel controller counts the serial communication data packets until the counting is completed. The sending and receiving time T of the data packet transmitted by the sampling chip signal to the parallel controller is calculated based on the count value. trans1 , the calculation formula is as follows:

[0081] T trans1 =N·M·T clk

[0082] Among them, T trans1is the time it takes for the sampling chip signal to be transmitted to the parallel controller, N is the count value of the serial communication data packet by the parallel controller, M is the number of bits contained in each data packet, and T clk is the clock period of the grid-connected controller.

[0083] Similarly, on the grid-connected controller side, a separate pulse signal can be triggered to obtain the analog-to-digital conversion time T of the sampling AD chip. conv2 (determined by the grid-connected AD chip itself), and the time T for the sampling chip signal to be transmitted to the grid-connected controller trans5 The grid voltage sampling delay is calculated based on the delay times obtained on the parallel controller side and the grid-connected controller side. This method can measure the grid voltage sampling delay with the highest accuracy to a single clock cycle within the parallel controller and the grid-connected controller, achieving higher-precision measurement. The calculation formula is as follows:

[0084] T delay1 =T conv1 +T trans1 -(T conv2 +T trans5 )

[0085] Among them, T delay1 is the grid voltage sampling delay, T conv1 T is the analog-to-digital conversion time of the AD chip sampling on the parallel controller side, trans1 T is the time it takes for the sampling chip signal to be transmitted to the parallel controller. conv2 T is the analog-to-digital conversion time of the sampling AD chip on the grid-connected controller side, trans5 It is the time taken for the sampling chip signal to be transmitted to the grid controller.

[0086] As a preferred solution of this embodiment, the command transmission delay is estimated by using a triggering separate pulse signal. First, a triggering separate pulse signal is sent from the parallel controller on the energy storage power supply vehicle to the parallel coordination controller. After the coordination controller receives the signal, it immediately sends the next triggering separate pulse signal to the grid coordination controller, and finally sends it to the grid coordination controller. By this method, the command transmission delay T is measured and calculated. delay2 , including the processor delay of each controller during the transmission process and the delay of the signal data packet during the transmission process. The processor delay during the transmission process is calculated as follows:

[0087] T mcu* =T end -T start

[0088] T mcu =T mcu1 +T mcu2 +T mcu3

[0089] Among them, T mcu* is the single processor delay, T end The end data processing time of a single processor, T start The start time of data processing for a single processor, T mcu is the total processor delay during the transmission process, T mcu1 T is the parallel controller processor delay during transmission. mcu2 T is the delay of the parallel coordination controller processor during the transmission process. mcu3 It is the grid coordination controller processor delay during the transmission process.

[0090] The delay in sending and receiving signal packets during this process can be measured using the chip counters of each controller. By adding the signal packet transmission delays between each controller, the total signal packet transmission delay can be obtained. The specific calculation is as follows:

[0091] T trans* =N * ·M * ·T clk *

[0092] T trans =T trans2 +T trans3 +T trans4

[0093] Among them, T trans* is the signal transmission time between each controller, N * M is the count value of serial communication data packets by each controller, * is the number of bits contained in the corresponding data packet in each controller, T clk * is the clock period of each controller, T trans is the total signal data packet transmission delay, T trans2 T is the signal transmission time between the parallel controller and the parallel coordination controller. trans3 T is the signal transmission time between the parallel coordination controller and the grid coordination controller, trans4 It is the signal transmission time between the parallel coordination controller and the grid-connected controller.

[0094] Finally, the instruction transmission delay T can be calculated delay2 :

[0095] T delay2 =T mcu +T trans

[0096] Where T delay2 is the instruction transmission delay, T mcuis the total processor delay during the transmission process, T trans is the total signal packet transmission delay.

[0097] As a preferred solution of this embodiment, the closing action delay is estimated by using a triggering separate pulse signal. The grid-connected controller of the energy storage power supply vehicle receives and processes the triggering separate pulse signal, and then sends a closing instruction to the closing controller of the power supply vehicle. After receiving the instruction, the closing controller needs to wait for its own fixed time to finally realize the closing of the circuit breaker. The delays included in this process are the processor delay of the grid-connected controller and the fixed action delay of the circuit breaker closing. The calculation method of the processor delay of the grid-connected controller is the same as that of the single processor delay, which will not be repeated here; the fixed action delay of the circuit breaker closing can be obtained according to the technical specification of the contactor. At this time, the closing action delay T can be calculated. delay3 , the calculation formula is as follows:

[0098] T delay3 =T mcu4 +T sw

[0099] Among them, T delay3 T is the closing action delay, mcu4 is the grid-connected controller processor delay, T sw It is the fixed action delay for closing.

[0100] As a preferred solution of this embodiment, the phase angle for connecting to the mains grid is recalculated based on the obtained delay time, specifically including:

[0101] ①Determine the grid voltage phase

[0102] The grid voltage is sampled in the sampling devices on the parallel controller and the grid controller side respectively. The voltage phase corresponding to the grid connection point is measured in real time through the phase-locked loop technology to obtain the grid voltage phase angle φ. This data is the basis for obtaining the grid connection phase angle.

[0103] ②Calculate the phase difference corresponding to the delay time

[0104] According to the obtained delay time, the total delay time ΔT can be obtained, and then the corresponding phase difference Δθ can be calculated. Assuming the grid voltage frequency is f, the corresponding phase difference can be calculated by the following formula

[0105] ΔT=T delay1 +T delay2 +T delay3

[0106] Δθ=2πfΔT

[0107] ③ Adjust the grid-connected phase angle in the control signal to meet the grid-connected requirements

[0108] Assuming that the grid-connected phase angle of the energy storage power supply vehicle's output grid-connected voltage is φ', then according to the phase difference Δθ calculated in step ②, the phase value of the grid-connected voltage that the energy storage power supply vehicle should output during the grid-connected process can be calculated. At the same time, it should also be considered that the phase difference between the output grid-connected voltage and the grid voltage sometimes needs to meet a specific value. Assume that this phase difference value is θ re , then the phase φ' of the output grid-connected voltage that needs to be adjusted is calculated as follows:

[0109] φ'=φ+Δθ+θ re

[0110] Where φ' is the grid-connected phase angle of the energy storage power supply vehicle, φ is the grid voltage phase angle measured by the data acquisition device, Δθ is the phase difference calculated based on the grid voltage sampling delay, command transmission delay and closing action delay, and θ re It is the phase difference that needs to be satisfied between the output grid-connected voltage and the grid voltage.

[0111] Through the above steps and formulas, it is possible to recalculate the phase angle required for grid connection based on the obtained delay time, thereby significantly reducing the angle error when the energy storage power supply vehicle is connected to the grid.

[0112] like Figure 4 As shown, the present invention provides a method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle. During the startup and grid connection process of the energy storage power supply vehicle, the energy management system of the energy storage power supply vehicle is simultaneously activated and the grid-side voltage, frequency, and phase angle are detected. Based on the obtained grid voltage, phase angle, frequency, and other data information, and taking into account factors such as phase difference caused by delay, the grid-connected phase angle is recalculated. Based on this, an operation control signal for the grid-connected inverter is generated. The detected output grid-connected voltage, frequency, and phase angle of the energy storage power supply vehicle are compared with the sampled data of the grid-side voltage, frequency, and phase angle. When the voltage and frequency across the circuit breaker are close and meet the grid connection requirements, the closing controller issues a closing signal to complete the closing operation. When the grid-side operation returns to a stable state, the voltage, phase angle, frequency, and other data information collected across the circuit breaker is used to determine whether the energy storage power supply vehicle meets the conditions for switching to an off-grid state. The closing controller then sends an opening signal to the circuit breaker, allowing a smooth and seamless switch to a state where only the grid-side load is supplied.

[0113] In this embodiment, more accurate grid-connected closing signal control is achieved by utilizing devices such as power electronic converters. Using the recalculated output grid-connected voltage phase angle, the DC voltage of the energy storage power supply vehicle is first converted to a voltage level corresponding to grid connection through a DC converter. Then, based on the principle of pulse width modulation (PWM) technology, the power electronic converter is used to precisely control the PWM signal. Finally, a dual-loop PI control method of voltage and current loops is used to adjust the amplitude and phase of the grid-connected voltage output by the grid-connected inverter, thereby improving the control accuracy of the grid-connected closing signal.

[0114] In this embodiment, the grid-connected current impact is reduced and flexible grid connection of the device is achieved. During the startup process, the energy storage power supply vehicle's energy management system is pre-started and the grid-side voltage, frequency, and phase angle are detected. Based on the obtained voltage, phase angle, frequency, and other data information, and taking into account the phase difference caused by delay, the grid-connected phase angle is recalculated. Based on this, the grid-connected inverter operation control signal is generated. The detected output grid-connected voltage, frequency, and phase angle of the energy storage power supply vehicle are compared with the sampled data of the grid-side voltage, frequency, and phase angle. When the voltage and frequency across the circuit breaker are close and meet the grid connection requirements, the closing controller issues a closing signal to complete the closing operation, thereby reducing the grid-connected current impact and achieving flexible grid connection of the energy storage power supply vehicle. When the grid-side operation returns to a stable state, the voltage, phase angle, frequency, and other data information collected across the circuit breaker are similarly used to determine whether the energy storage power supply vehicle can be switched to an off-grid state. The closing controller sends a trip signal to the circuit breaker, at which point the vehicle can smoothly and seamlessly switch to a state where only the grid-side load is supplied, and the power system continues to operate stably.

[0115] The embodiment of the present invention can significantly reduce the grid connection angle error of the energy storage power supply vehicle, while reducing the grid connection current impact, realizing flexible grid connection of the energy storage power supply vehicle, and reducing the impact of the energy storage power supply vehicle on the grid side during the grid connection and disconnection process.

[0116] Based on the same inventive concept, the present invention also provides a computer device, which includes: one or more processors and a memory for storing one or more computer programs; the program includes program instructions, and the processor is used to execute the program instructions stored in the memory. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is used to implement one or more instructions, specifically for loading and executing one or more instructions in a computer storage medium to implement the above method.

[0117] It should be further explained that, based on the same inventive concept, the present invention also provides a computer storage medium having a computer program stored thereon, which executes the above method when executed by a processor. The storage medium can be any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, infrared, or semiconductor system, device or component, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, device or component.

[0118] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0119] The above shows and describes the basic principles, main features and advantages of the present disclosure. Those skilled in the art should understand that the present disclosure is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present disclosure. Various changes and improvements may be made to the present disclosure without departing from the spirit and scope of the present disclosure, and such changes and improvements shall fall within the scope of the present disclosure.

[0120] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive various other forms of a method, device and energy storage power supply vehicle for controlling grid connection and disconnection under the guidance of the present invention. All equivalent changes and modifications made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle, characterized in that: By triggering a separate pulse signal, the following delays in the energy storage power supply vehicle's on-grid and off-grid switching process are estimated synchronously: Grid voltage sampling delay: This is calculated based on the analog-to-digital conversion time difference and signal transmission time difference between the parallel generator side and the grid side; Instruction transmission delay: calculated by dynamically accumulating the processor processing time and signal transmission time between controllers; Closing action delay: calculated by combining the grid controller processing time and the circuit breaker inherent action time; The phase difference is calculated in real time based on the total delay, and the phase angle of the grid-connected voltage output by the energy storage power supply vehicle is dynamically adjusted by superimposing the preset phase difference; Through the dual-loop PI control strategy of the power electronic converter, the dynamically adjusted phase angle of the grid-connected inverter output is adjusted to achieve low-impact flexible grid connection of the energy storage power supply vehicle.

2. The method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle according to claim 1, characterized in that: The grid voltage sampling delay is calculated by collaboratively comparing the analog-to-digital conversion and signal transmission time difference between the parallel generator side and the grid-connected side, specifically: The signal transmission time on the parallel side is based on the number of serial communication data packets N, the number of bits M and the controller clock cycle T clk Calculate and satisfy T trans1 =N·M·T clk ; The signal transmission time on the grid side is calculated based on the corresponding controller parameters; The total sampling delay is calculated based on the following formula: T delay1 =T conv1 +T trans1 -(T conv2 +T trans5 ) Among them, T delay1 is the grid voltage sampling delay, T conv1 T is the analog-to-digital conversion time of the AD chip sampling on the parallel controller side, trans1 T is the time it takes for the sampling chip signal to be transmitted to the parallel controller. conv2 T is the analog-to-digital conversion time of the sampling AD chip on the grid-connected controller side, trans5 It is the time taken for the sampling chip signal to be transmitted to the grid controller.

3. The method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle according to claim 1, wherein: The calculation of the instruction transmission delay is achieved by synchronously measuring the processing and transmission time between controllers through the trigger pulse signal: T delay2 =T mcu +T trans , specifically including: Total processor processing time T mcu The dynamic accumulation calculation is performed through the time stamp difference of the trigger pulse signal of the parallel controller, parallel coordination controller, and grid coordination controller. The formula is: T mcu* =T end -T start T mcu =T mcu1 +T mcu2 +T mcu3 Among them, T mcu* is the single processor delay, T end The end data processing time of a single processor, T start The start time of data processing for a single processor, T mcu is the total processor delay during the transmission process, T mcu1 T is the parallel controller processor delay during transmission. mcu2 T is the delay of the parallel coordination controller processor during the transmission process. mcu3 To coordinate the controller processor delay for the grid connection during transmission; Total signal transmission time T trans Calculated by accumulating the data packet transmission time between controllers: T trans* =N * ·M * ·T clk * T trans =T trans2 +T trans3 +T trans4 Among them, T trans* is the signal transmission time between each controller, N * M is the count value of serial communication data packets by each controller, * is the number of bits contained in the corresponding data packet in each controller, T clk * is the clock period of each controller, T trans is the total signal data packet transmission delay, T trans2 T is the signal transmission time between the parallel controller and the parallel coordination controller. trans3 T is the signal transmission time between the parallel coordination controller and the grid coordination controller, trans4 It is the signal transmission time between the parallel coordination controller and the grid-connected controller.

4. The method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle according to claim 1, wherein: The calculation of the closing action delay is achieved by dynamically measuring the processing time of the grid-connected controller and combining it with the inherent action time of the circuit breaker. The formula is: T delay2 =T mcu +T trans Where: T delay2 is the instruction transmission delay, T mcu is the total processor delay during the transmission process, T trans is the total signal packet transmission delay.

5. The method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle according to claim 1, characterized in that: Dynamically adjust the grid-connected phase angle based on the total delay, specifically including: According to the grid voltage frequency f and the total delay ΔT, the phase difference is calculated using the formula Δθ=2πfΔT; The grid-connected phase difference θ is preset by superimposing the real-time grid voltage phase angle φ re , dynamically adjust the phase angle φ' of the output grid-connected voltage, the formula is: φ'=φ+Δθ+θ re Among them, the grid voltage phase angle φ is obtained by measuring the grid connection point voltage phase in real time through the phase-locked loop technology, θ re It is the preset value adapted to the power grid scenario.

6. The method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle according to claim 1, characterized in that: The control of the power electronic converter includes: Adjust the output voltage level of the energy storage power supply vehicle through the DC converter; Generate inverter control signals based on PWM technology; A dual-loop PI control strategy of voltage loop and current loop is used to adjust the grid voltage amplitude and phase.

7. The method for controlling the on-grid and off-grid operation of an energy storage power supply vehicle according to claim 1, characterized in that: The triggering conditions for flexible grid connection are: when it is detected that the voltage difference across the circuit breaker is less than the preset voltage difference threshold and the frequency difference is less than the preset frequency difference threshold, the closing signal is triggered; the off-grid switching conditions are: when the grid side recovers and the difference between the output voltage of the energy storage power supply vehicle and the grid voltage is less than the dynamically set threshold, the opening signal is triggered.

8. A grid-connected and off-grid control device for energy storage power supply vehicles, characterized in that: include: The delay estimation module is used to synchronously estimate the grid voltage sampling delay, command transmission delay and closing action delay by triggering a separate pulse signal; The phase compensation module is used to calculate the phase difference in real time based on the total delay, and dynamically adjust the phase angle of the grid-connected voltage output by the energy storage power supply vehicle by superimposing the preset phase difference; The power electronic converter control module is used to adjust the dynamically adjusted phase angle of the grid-connected inverter output through a dual-loop PI control strategy to achieve flexible grid connection.

9. The energy storage power supply vehicle on-grid and off-grid control device according to claim 8, characterized in that: The delay estimation module includes: A sampling delay calculation unit is configured to collaboratively compare the analog-to-digital conversion and signal transmission time difference between the parallel side and the grid side; an instruction transmission delay calculation unit configured to dynamically accumulate processor processing time and signal transmission time between controllers; The closing action delay calculation unit is configured to combine the processing time of the grid-connected controller and the inherent action time of the circuit breaker. The phase compensation module includes: Phase-locked loop unit, used for real-time measurement of grid voltage phase angle φ; a phase difference calculation unit configured to calculate the phase difference according to the grid voltage frequency f and the total delay ΔT using a formula Δθ=2πfΔT; A dynamic superposition unit is configured to preset a grid-connected phase difference θ by superimposing a real-time grid voltage phase angle φ re , dynamically adjust the phase angle φ' of the output grid-connected voltage, the formula is: φ'=φ+Δθ+θ re Among them, θ re It is the preset value adapted to the power grid scenario.

10. An energy storage power supply vehicle, characterized in that: The invention comprises the on-grid and off-grid control device according to claim 8 or 9, and: An energy storage unit, used to store electrical energy and output it to the inverter through a DC converter; a grid-connected inverter configured to output a dynamically adjusted voltage and phase angle according to a regulation signal from the control device; The circuit breaker is used to perform closing or opening operations when flexible grid connection or disconnection conditions are met.

Images