Mobile power resource parallel operation and grid connection control method and system

Abstract

The invention discloses a multi-type mobile power resource parallel operation and grid connection control method and system based on a virtual synchronous generator, and the method employs a virtual synchronous generator control technology to control a mobile energy storage vehicle. By adjusting corresponding coefficients in the controller, free distribution of the output power in a parallel operation off-grid power supply scene of the mobile energy storage vehicle and the diesel power generation vehicle is realized, a foundation is laid for further researching an optimal strategy of power distribution, loss and cost are reduced, and the economical efficiency of a novel power system is improved. And two groups of amplitude, frequency and phase controllers are innovatively adopted, and the two groups of controllers are combined and complemented by utilizing a parallel operation and grid connection switching control strategy, so that the pre-synchronization grid connection operation is performed on the premise of ensuring the safety and stability of a parallel operation system, and the method is matched with the parallel operation and grid connection power supply process of the mobile energy storage vehicle and the diesel power generation vehicle; and the instability risk of the parallel operation power supply system caused by the influence of the grid-connected operation is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of transportation electrification, and in particular to a method for controlling the parallel operation and grid connection of multiple types of mobile power resources based on virtual synchronous generators. Background Art

[0002] With the continuous development of social economy and the transformation of energy structure, various types of mobile power resources such as diesel generators, mobile energy storage vehicles and electric vehicles have become an important support for improving the control capacity of distribution networks. Various types of mobile power resources are flexible and dispatchable, which can provide temporary energy replenishment and emergency support for distribution networks, and can effectively cope with energy and load fluctuations. However, the current coordinated control capabilities of various types of mobile power resources temporarily connected to the distribution network are insufficient, and cannot adapt to the application requirements of various scenarios such as temporary capacity expansion, emergency power supply and load power protection of the distribution network. Therefore, it is of vital importance to study the joint operation and intelligent control strategies of the parallel and grid-connected access of various types of mobile power resources.

[0003] At present, the charging and discharging control strategies used by mobile energy storage vehicles are mainly divided into two categories: the PQ control strategy for grid-connected operation and the V / f control strategy for island operation. The PQ control strategy for grid-connected operation can stably output the specified active power and reactive power under the condition that the grid provides voltage and frequency support, but the PQ control strategy cannot provide voltage and frequency support for the overall system. The V / f control strategy for island operation can provide voltage and frequency support from the mobile energy storage vehicle to maintain system stability in the absence of voltage and frequency support from the grid, but due to the locking of the system frequency and voltage, the active and reactive power of the parallel diesel generator vehicle is constant. When the load increases, all the increased active power and reactive power are borne by the mobile energy storage vehicle alone, which is not conducive to the safe and stable operation of the microgrid. Therefore, the existing control methods for paralleling and connecting multiple types of mobile power resources to the grid still have defects. Summary of the invention

[0004] The invention patent aims to solve the shortcomings of the existing mobile energy storage vehicle and diesel generator vehicle parallel and grid-connected control methods, especially the power distribution problem when the load increases and the difficulty in switching between on-grid and off-grid power supply modes. A multi-type mobile power resource parallel and grid-connected control method and system based on a virtual synchronous generator is proposed.

[0005] The present invention adopts the following technical means to achieve: a control method for paralleling and connecting multiple types of mobile power resources based on virtual synchronous generators, the control method is used to parallel and connect the power resources between the running mobile energy storage vehicle and the diesel generator vehicle, and includes the following steps:

[0006] Start the mobile energy storage vehicle and read the control moment of inertia J, damping coefficient D, and active power reference value P of the synchronous generator on the mobile energy storage vehicle.ref and reactive power reference value Q ref , a virtual synchronous generator model is constructed through the moment of inertia, damping coefficient, active power reference value, and reactive power reference value;

[0007] Read the amplitude, frequency and phase information of the voltage of the diesel generator car, and control the amplitude, frequency and phase of the output voltage of the mobile energy storage car through the virtual synchronous generator, so that they are consistent with the amplitude, frequency and phase of the output voltage of the diesel generator car, respectively, close the diesel generator car and the mobile energy storage car to complete the parallel operation, and form a parallel system with the diesel generator car and the mobile energy storage car;

[0008] After the parallel system is stable, the voltage frequency and amplitude of the parallel system are synchronized with the voltage frequency and amplitude of the power grid through the virtual synchronous generator model, so that the voltage amplitude and frequency of the grid connection point are consistent with the voltage amplitude and frequency of the grid, and the parallel system and the grid are closed to complete the grid connection.

[0009] Furthermore, the virtual synchronous generator model includes a rotor mechanical characteristic equation equivalent control module and a stator electrical characteristic equation equivalent control module, and the rotor mechanical characteristic equation equivalent control module and the stator electrical characteristic equation equivalent control module jointly generate a signal to control the output voltage of the mobile energy storage vehicle;

[0010] The input of the rotor mechanical characteristic equation equivalent control module is the mechanical power P of the virtual synchronous generator. m and the electromagnetic power P of the virtual synchronous generator e , and taking the moment of inertia J and the damping coefficient D as parameters, the output of the rotor mechanical characteristic equation equivalent control module is the electrical angular velocity ω, which satisfies:

[0011]

[0012] Among them, P m is the mechanical power of the virtual synchronous generator, P e is the electromagnetic power of the virtual synchronous generator, ω is the electrical angular velocity of the virtual synchronous generator, ω n is the rated electrical angular velocity, the active power reference value P of the virtual synchronous generator ref As mechanical power P m , the active power at the grid-connected node is taken as the electromagnetic power P e ;

[0013] The stator electrical characteristic equation equivalent control module satisfies:

[0014]

[0015] in, is the excitation electromotive force of the virtual synchronous generator, the phase angle θ obtained by integrating the electrical angular velocity ω and the excitation electromotive force amplitude E of the virtual synchronous generator 0 Combined to obtain, is the armature terminal voltage of the virtual synchronous generator, is the armature current of the virtual synchronous generator, R a is the armature resistance, X s is the synchronous reactance.

[0016] In the present invention, the amplitude, frequency and phase of the output voltage of the mobile energy storage vehicle are controlled by a virtual synchronous generator, and the specific steps are as follows:

[0017] The electrical angular velocity ω is obtained by the equivalent control module of the rotor mechanical characteristic equation. The electrical angular velocity ω is passed through the integrator to obtain the phase angle θ. The reactive power at the grid-connected node is read and the difference between the set reactive power reference value is obtained to obtain the excitation electromotive force amplitude E. 0 , with E 0 is the amplitude, θ is the phase angle to get the A phase excitation electromotive force, the A phase excitation electromotive force is delayed by 120° and 240° respectively to get the B phase and C phase excitation electromotive force, the excitation electromotive force is synthesized from the three phases A, B and C;

[0018] According to the stator electrical characteristic equation equivalent control module, the armature resistance R of the synchronous generator is a and synchronous reactance X s The sum of the armature current of the virtual synchronous generator Multiply them together to get the stator voltage drop;

[0019] The armature terminal voltage of the virtual synchronous generator is obtained by subtracting the excitation electromotive force from the stator voltage drop. The voltage command is obtained through voltage and current dual closed-loop control, and a PWM signal is generated to control the amplitude, frequency and phase of the output voltage of the mobile energy storage vehicle.

[0020] The present invention controls the output voltage amplitude of the mobile energy storage vehicle by changing its voltage reference value Un. When the output voltage amplitude of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the voltage reference value of the mobile energy storage vehicle is reduced, and vice versa, the voltage reference value is increased until the output voltage amplitude of the mobile energy storage vehicle is equal to the voltage amplitude of the diesel generator vehicle.

[0021] The control of the output voltage frequency of the mobile energy storage vehicle by the virtual synchronous generator model of the present invention is achieved by changing its active power reference value, that is, the pf drop characteristic curve. When the output voltage frequency of the mobile energy storage vehicle is higher than the voltage frequency of the diesel generator vehicle, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the voltage frequency of the diesel generator vehicle, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output voltage frequency of the mobile energy storage vehicle is equal to the output voltage frequency of the diesel generator vehicle.

[0022] The virtual synchronous generator model of the present invention changes the output voltage phase of the mobile energy storage vehicle by changing its initial output voltage phase. When the output voltage phase of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the initial output voltage phase of the mobile energy storage vehicle is reduced, and vice versa, the initial output voltage phase is increased until the output voltage phase of the mobile energy storage vehicle is the same as that of the diesel generator vehicle.

[0023] When the following conditions are met, the parallel system is considered stable:

[0024]

[0025] Among them U 0 is the output voltage amplitude of the mobile energy storage vehicle, U gen is the output voltage amplitude of the diesel generator car, ΔU max The maximum voltage difference allowed to maintain system stability, ω 0 is the output frequency of the mobile energy storage vehicle, ω gen is the output frequency of the diesel generator, Δω max The maximum frequency difference allowed to maintain system stability is: Output voltage phase of mobile energy storage vehicle, is the output voltage phase of the diesel generator car, The maximum phase difference allowed to keep the system stable.

[0026] Before the parallel system is connected to the grid, the following steps are also required:

[0027] The voltage amplitude between the parallel system and the power grid is adjusted by adjusting the voltage reference value Un of the mobile energy storage vehicle in the parallel system. Specifically, when the output voltage amplitude of the parallel system is higher than the voltage amplitude of the power grid, the voltage reference value of the mobile energy storage vehicle is reduced; when the output voltage amplitude of the parallel system is lower than the voltage amplitude of the power grid, its voltage reference value is increased until the output voltage amplitude of the parallel system is equal to the voltage amplitude of the power grid.

[0028] Before the parallel system is connected to the grid, the following steps are also required:

[0029] The frequency between the parallel system and the power grid is adjusted by adjusting the active power reference value of the mobile energy storage vehicle in the parallel system, that is, the pf drop characteristic curve. Specifically, when the output voltage frequency of the mobile energy storage vehicle is higher than the grid voltage frequency, the controller output is a negative value, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the grid voltage frequency, the controller output is a positive value, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output frequency of the parallel system is equal to the grid frequency.

[0030] The present invention also includes a method for adjusting the phase between the parallel system and the power grid when the frequencies of the parallel system and the power grid are equal and the phases of the parallel system and the power grid are not equal. The method is achieved by adjusting the active power reference value of the mobile energy storage vehicle in the parallel system, that is, the pf drop characteristic curve, to control the frequency difference between the parallel system and the power grid. Specifically, when the phase of the parallel system is lower than the phase of the power grid, the Pf drop characteristic curve is shifted upward so that the frequency of the parallel system is greater than the frequency of the power grid, and the phase of the parallel system increases relative to the phase of the power grid; when the phase of the parallel system is greater than the phase of the power grid, the Pf drop characteristic curve is shifted downward so that the frequency of the parallel system is less than the frequency of the power grid, and the phase of the parallel system decreases relative to the phase of the power grid until the phase of the parallel system is equal to the phase of the power grid.

[0031] The present invention also relates to a mobile power resource parallel machine and grid control system, comprising:

[0032] Model building module, used to start the mobile energy storage vehicle and read the control moment of inertia J, damping coefficient D, and active power reference value P of the synchronous generator on the mobile energy storage vehicle ref and reactive power reference value Q ref , a virtual synchronous generator model is constructed through the moment of inertia, damping coefficient, active power reference value, and reactive power reference value;

[0033] The parallel module is used to read the amplitude, frequency and phase information of the diesel generator vehicle voltage, and control the amplitude, frequency and phase of the mobile energy storage vehicle output voltage through the virtual synchronous generator to make them consistent with the amplitude, frequency and phase of the diesel generator vehicle output voltage, and close the diesel generator vehicle and the mobile energy storage vehicle to complete the parallel operation, forming a parallel system with the diesel generator vehicle and the mobile energy storage vehicle.

[0034] The grid-connected module is used to synchronize the voltage frequency and amplitude of the parallel system with the voltage frequency and amplitude of the power grid through a virtual synchronous generator model after the parallel system is stable, so that the voltage amplitude and frequency of the grid-connected point are consistent with the voltage amplitude and frequency of the power grid, and the parallel system and the power grid are closed to complete the grid connection.

[0035] The model building module includes:

[0036] The rotor mechanical characteristic equation equivalent control module is used to simulate the mechanical characteristics of the synchronous generator rotor. Its input is the mechanical power P of the virtual synchronous generator. m and the electromagnetic power P of the virtual synchronous generator e , and take the moment of inertia J and damping coefficient D as parameters, and output the electrical angular velocity ω, which satisfies:

[0037]

[0038] Among them, P m is the mechanical power of the virtual synchronous generator, P e is the electromagnetic power of the virtual synchronous generator, ω is the electrical angular velocity of the virtual synchronous generator, ω n is the rated electrical angular velocity, the active power reference value p of the virtual synchronous generator ref As mechanical power P m , the active power at the grid-connected node is taken as the electromagnetic power P e ;

[0039] Stator electrical characteristic equation equivalent control module is used to simulate the stator electrical characteristics of the synchronous generator. Its input is the armature terminal voltage of the virtual synchronous generator. and the armature current of the virtual synchronous generator And the armature resistance R a and synchronous reactance X s As a parameter, the output is the armature terminal voltage of the virtual synchronous generator It satisfies:

[0040]

[0041] in, is the excitation electromotive force of the virtual synchronous generator, the phase angle θ obtained by integrating the electrical angular velocity ω and the excitation electromotive force amplitude E of the virtual synchronous generator 0 Combined to obtain, is the armature terminal voltage of the virtual synchronous generator, is the armature current of the virtual synchronous generator, R a is the armature resistance, X s is the synchronous reactance.

[0042] The specific steps of the parallel module controlling the amplitude, frequency and phase of the output voltage of the mobile energy storage vehicle are as follows:

[0043] The electrical angular velocity ω is obtained by the equivalent control module of the rotor mechanical characteristic equation. The electrical angular velocity ω is passed through the integrator to obtain the phase angle θ. The reactive power at the grid-connected node is read and the difference between the set reactive power reference value is obtained to obtain the excitation electromotive force amplitude E. 0 , with E0 is the amplitude, θ is the phase angle to get the A phase excitation electromotive force, the A phase excitation electromotive force is delayed by 120° and 240° respectively to get the B phase and C phase excitation electromotive force, the excitation electromotive force is synthesized from the three phases A, B and C;

[0044] According to the stator electrical characteristic equation equivalent control module, the armature resistance R of the synchronous generator is a and synchronous reactance X s The sum of the armature current of the virtual synchronous generator Multiply them together to get the stator voltage drop;

[0045] The armature terminal voltage of the virtual synchronous generator is obtained by subtracting the excitation electromotive force from the stator voltage drop. The voltage command is obtained through voltage and current dual closed-loop control, and a PWM signal is generated to control the amplitude, frequency and phase of the output voltage of the mobile energy storage vehicle.

[0046] The parallel module controls the output voltage amplitude of the mobile energy storage vehicle by changing its voltage reference value Un. When the output voltage amplitude of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the voltage reference value of the mobile energy storage vehicle is reduced, otherwise the voltage reference value is increased until the output voltage amplitude of the mobile energy storage vehicle is equal to the voltage amplitude of the diesel generator vehicle.

[0047] The parallel module controls the output voltage frequency of the mobile energy storage vehicle by changing its active power reference value, i.e., the pf drop characteristic curve. When the output voltage frequency of the mobile energy storage vehicle is higher than the voltage frequency of the diesel generator vehicle, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the voltage frequency of the diesel generator vehicle, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output voltage frequency of the mobile energy storage vehicle is equal to the output voltage frequency of the diesel generator vehicle.

[0048] The parallel module changes the output voltage phase of the mobile energy storage vehicle by changing its initial output voltage phase. When the output voltage phase of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the initial output voltage phase of the mobile energy storage vehicle is reduced, otherwise the initial output voltage phase is increased until the output voltage phase of the mobile energy storage vehicle is the same as that of the diesel generator vehicle.

[0049] The parallel module determines that the parallel system is stable when the following conditions are met:

[0050]

[0051] Among them U 0 is the output voltage amplitude of the mobile energy storage vehicle, U gen is the output voltage amplitude of the diesel generator car, ΔU maxThe maximum voltage difference allowed to maintain system stability, ω 0 is the output frequency of the mobile energy storage vehicle, ω gen is the output frequency of the diesel generator, Δω max The maximum frequency difference allowed to maintain system stability is: Output voltage phase of mobile energy storage vehicle, is the output voltage phase of the diesel generator car, The maximum phase difference allowed to keep the system stable.

[0052] The grid-connected control module adjusts the voltage amplitude between the parallel system and the power grid by adjusting the voltage reference value Un of the mobile energy storage vehicle in the parallel system. Specifically, when the output voltage amplitude of the parallel system is higher than the voltage amplitude of the power grid, the voltage reference value of the mobile energy storage vehicle is reduced; when the output voltage amplitude of the parallel system is lower than the voltage amplitude of the power grid, its voltage reference value is increased until the output voltage amplitude of the parallel system is equal to the voltage amplitude of the power grid.

[0053] The grid-connected control module adjusts the frequency between the parallel system and the power grid by adjusting the active power reference value of the mobile energy storage vehicle in the parallel system, that is, the pf drop characteristic curve. Specifically, when the output voltage frequency of the mobile energy storage vehicle is higher than the grid voltage frequency, the controller output is a negative value, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the grid voltage frequency, the controller output is a positive value, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output frequency of the parallel system is equal to the grid frequency.

[0054] The grid-connected control module adjusts the phase between the parallel system and the grid by adjusting the active power reference value of the mobile energy storage vehicle in the parallel system, that is, the pf drop characteristic curve to control the frequency difference between the parallel system and the grid. Specifically, when the phase of the parallel system is lower than the phase of the grid, the Pf drop characteristic curve is shifted upward so that the frequency of the parallel system is greater than the grid frequency, and the phase of the parallel system increases relative to the grid phase; when the phase of the parallel system is greater than the grid phase, the Pf drop characteristic curve is shifted downward so that the frequency of the parallel system is less than the grid frequency, and the phase of the parallel system decreases relative to the grid phase until the phase of the parallel system is equal to the grid phase.

[0055] The present invention also relates to a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements any of the aforementioned methods for controlling parallel operation and grid connection of multiple types of mobile power resources based on a virtual synchronous generator.

[0056] The present invention also relates to a computer-readable storage medium having a computer program stored thereon, wherein the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute any of the aforementioned methods for controlling parallel operation and grid connection of multiple types of mobile power resources based on a virtual synchronous generator.

[0057] The present invention is based on virtual synchronous generator control technology, and realizes the unification of multi-scenario control strategies for power supply of a single mobile energy storage vehicle, parallel power supply with a diesel generator vehicle, and parallel power supply to the grid. It avoids the switching of control strategies when switching between scenarios, eliminates the risk of instability caused by switching of control strategies, reduces the risk of users' multiple power ons and offs in a short period of time, and improves the overall stability of the parallel power and grid-connected system.

[0058] The present invention adopts virtual synchronous generator control technology to control the mobile energy storage vehicle. Through the virtual synchronous generator control technology, the free distribution of output power in the off-grid power supply scenario of the mobile energy storage vehicle and the diesel generator vehicle is realized, which lays the foundation for further research on the optimal strategy of power distribution, is conducive to reducing losses and costs, and improving the economy of the new power system.

[0059] The present invention innovatively adopts two sets of amplitude, frequency and phase controllers, and utilizes the parallel-grid switching control strategy to combine and complement the two sets of controllers, thereby ensuring pre-synchronization and grid-connected operation under the premise of safe and stable parallel system, which is suitable for the parallel-grid power supply process of mobile energy storage vehicles and diesel generator vehicles, and avoids the risk of instability of the parallel power supply system caused by the influence of grid-connected operation.

[0060] The present invention adopts a modular concept and can independently optimize and change each link of the control strategy without affecting other parts of the overall model, so that it can not only adapt to various types of mobile power resources, but also adjust the control strategy parameters according to the characteristics of other grid-connected power sources such as fixed energy storage, photovoltaic and wind power new energy, to meet the possible parallel connection and grid-connection requirements of the above-mentioned grid-connected power sources, and has good scalability.

[0061] Compared with other methods, the control complexity of the present invention is lower, the degree of automation is higher, the operating burden of the staff of the mobile energy storage vehicle is reduced, and good economic benefits are achieved.

[0062] The implementation of this invention will help promote the exploration of the potential of various types of mobile power resources and help the safe and stable operation of new power systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a schematic diagram of the control model of the virtual synchronous generator of the present invention;

[0064] Figure 2 It is a schematic diagram of a parallel virtual synchronous generator model;

[0065] Figure 3 Schematic diagram of switching strategy for amplitude and frequency regulator;

[0066] Figure 4 This is a schematic diagram of the parallel voltage, frequency and phase difference in the simulation environment;

[0067] Figure 5 Schematic diagram of grid-connected voltage frequency and phase difference under simulation environment. DETAILED DESCRIPTION

[0068] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0069] The technical solution applied for in this patent is a control method for parallel connection and grid connection of mobile energy storage vehicles and diesel generator vehicles based on VSG. Comprehensively considering the voltage amplitude, frequency and phase conditions of parallel connection and grid connection, the powerful automatic adjustment ability of VSG control and its unified control ability of grid connection and off-grid connection are utilized, and amplitude regulator, frequency regulator and phase regulator are added to enhance the regulation ability of energy storage vehicles for voltage amplitude, frequency and phase, so as to realize parallel power supply of energy storage vehicles and diesel generator vehicles and rapid and stable grid connection of diesel-storage parallel connection system.

[0070] A. Virtual Synchronous Generator (VSG) Control Technology

[0071] The virtual synchronous generator simulates the damping and inertia characteristics, active frequency regulation and reactive voltage regulation characteristics of the synchronous generator in the control strategy, generates signals to control the inverter of the energy storage system, and makes the output characteristics of the energy storage system similar to those of the synchronous generator.

[0072] (1) Equivalent mathematical model of synchronous generator

[0073] The equivalent mathematical model of the synchronous generator consists of two parts: the rotor mechanical characteristic equation and the stator electrical characteristic equation.

[0074] ①Rotor mechanical characteristic equation

[0075] The rotor mechanical characteristic equation is mainly used to describe the dynamic behavior of the rotor in the synchronous generator model, that is, the relationship between the mechanical torque, electromagnetic torque and the rotor angular velocity.

[0076]

[0077] Where J is the moment of inertia of the synchronous generator, T m is the mechanical torque of the synchronous generator, T e is the electromagnetic torque of the synchronous generator, D is the damping coefficient, Ω is the rotor mechanical angular velocity of the synchronous generator, Ω n is the rated rotor mechanical angular speed.

[0078] In order to simplify the control as much as possible, it is assumed that the pole pair number of the synchronous generator is 1, then the rotor mechanical angular velocity Ω is equal to the synchronous generator electrical angular velocity ω, and the mechanical torque and electromagnetic torque are expressed by electromagnetic power and mechanical power, then formula (1) is simplified to formula (2).

[0079]

[0080] Among them, P m is the mechanical power of the synchronous generator, P e is the electromagnetic power of the synchronous generator, ω is the electrical angular velocity of the synchronous generator, ω n is the rated electrical angular velocity.

[0081] ② Stator electrical characteristic equation

[0082] The stator electrical characteristic equation is mainly used to describe the electrical part of the synchronous generator. It reflects the relationship between the voltage, current and flux in the stator winding. When the electromagnetic characteristics of the synchronous generator and the saturation eddy current loss of the magnetic circuit are ignored, the stator electrical equation can be simplified to the following form.

[0083]

[0084] Among them, e 0 is the three-phase excitation electromotive force of the synchronous generator, is the three-phase armature terminal voltage of the synchronous generator, is the three-phase armature current of the synchronous generator, R a is the armature resistance, L m is the synchronous reactance.

[0085] Writing the above formula in vector form, we can get the final form of the stator electrical characteristic equation:

[0086]

[0087] in, is the excitation electromotive force of the synchronous generator, is the armature terminal voltage of the synchronous generator, is the armature current of the synchronous generator, R a is the armature resistance, X s is the synchronous reactance.

[0088] (2) Virtual synchronous generator model

[0089] The virtual synchronous generator technology is based on the rotor mechanical characteristic equation and stator electrical characteristic equation of the synchronous generator equivalent model, establishes the corresponding transfer function and converts it into the corresponding control structure to achieve control of the energy storage output characteristics.

[0090] First, the equivalent control module of the rotor mechanical characteristic equation is constructed to convert the mechanical power P of the virtual synchronous generator into m The electromagnetic power of the virtual synchronous generator is taken as input, the moment of inertia J and the damping coefficient D are taken as parameters, and the electrical angular velocity ω is taken as output to build a control module.

[0091] After obtaining the electrical angular velocity ω output by the rotor mechanical characteristic equation, the stator electrical characteristic equation equivalent control module is then constructed. The excitation electromotive force of the synchronous generator is obtained by integrating ω: The phase angle θ is then summed up with the excitation electromotive force amplitude E 0 Combined Then and The three-phase armature terminal voltage is obtained by subtracting Complete the stator electrical characteristic equation equivalent control module.

[0092] like Figure 1 As shown, the specific control process is divided into the following 4 steps:

[0093] (1) Set the active power reference value P ref As mechanical power P m , read the active power at the grid-connected node as the electromagnetic power P e , the moment of inertia J and damping coefficient D are set according to the required inertia and damping, and the rotor mechanical characteristic equation equivalent control module can output the electrical angular velocity ω during control operation.

[0094] (2) The electrical angular velocity ω is passed through an integrator to obtain the phase angle θ. The reactive power at the grid-connected node is read and the difference between the reactive power reference value is obtained to obtain the excitation electromotive force amplitude E. 0 , with E 0 The excitation electromotive force of phase A is obtained by lagging the excitation electromotive force of phase A by 120° and 240° respectively to obtain the excitation electromotive force of phase B and phase C. The excitation electromotive force of phases A, B and C is obtained by synthesizing the three phases A, B and C.

[0095] (3) According to the stator electrical characteristic equation, the armature resistance R of the virtual synchronous machine is a and synchronous reactance X s The sum of the stator current of the virtual synchronous machine Multiply them together to get the stator voltage drop.

[0096] (4) Subtract the excitation electromotive force obtained in (2) from the stator voltage drop obtained in (3) to obtain the stator terminal voltage The voltage command is obtained through voltage and current dual closed-loop control, and a PWM signal is generated to control the inverter output voltage.

[0097] B. Virtual synchronous machine parallel control strategy

[0098] Mobile energy storage vehicles are often used in parallel with diesel generators to provide emergency power to the load. In order to ensure the safe and stable parallel operation of the energy storage vehicle and the diesel generator, the voltage amplitude, frequency and phase of the energy storage vehicle and the diesel generator must be consistent. In order to meet the three conditions for parallel synchronization, the virtual synchronous generator control is modified and three control links, namely the voltage amplitude controller, frequency controller and voltage phase controller, are added for control. The control strategy after adding the three control links is as follows: Figure 2 shown.

[0099] 1) Voltage amplitude controller

[0100] The output voltage amplitude of the virtual synchronous generator is determined by the decreasing characteristic curve of the output reactive power Q and the voltage amplitude U. In the parallel pre-synchronization scenario, the load power does not change. In order to ensure that the output reactive power is the same as the load reactive power, the output reactive power of the energy storage vehicle remains unchanged, and the output voltage amplitude cannot be adjusted by adjusting the output reactive power. The slope of the QU decreasing characteristic curve is determined by fixed parameters, which is difficult to change and has a more complex impact. Therefore, the voltage amplitude controller is set to act on the voltage reference value Un, and the difference between the output voltage amplitude of the energy storage vehicle and the output voltage amplitude of the diesel generator is input into the PI controller. When the voltage amplitude of the energy storage vehicle is higher than that of the diesel generator, the voltage reference value is reduced, and the QU decreasing characteristic curve is shifted downward as a whole, and the output voltage amplitude of the energy storage vehicle is reduced while keeping the output reactive power unchanged; when the voltage amplitude of the energy storage vehicle is lower than that of the diesel generator, the voltage reference value is increased, and the QU decreasing characteristic curve is shifted upward as a whole, and the output voltage amplitude of the energy storage vehicle is increased while keeping the output reactive power unchanged, so that it approaches the voltage amplitude of the diesel generator.

[0101] 2) Frequency controller

[0102] The output frequency of the virtual synchronous generator is determined by the decreasing characteristic curve of the output active power P and the frequency f. In the parallel pre-synchronization scenario, the load power does not change. In order to ensure that the output active power is the same as the load active power, the output active power of the energy storage vehicle remains unchanged, and the output frequency cannot be adjusted by adjusting the output active power. Therefore, the frequency generator is set to act on the active power reference value P ref The difference between the frequency of the energy storage vehicle and the frequency of the diesel vehicle is input into the PI controller. When the frequency of the energy storage vehicle is higher than the frequency of the diesel vehicle, the output of the PI controller is negative, and the active power reference value P ref The Pf decrease characteristic curve moves downward, the output active power remains unchanged while the frequency decreases; when the energy storage vehicle frequency is lower than the diesel vehicle frequency, the PI controller output is positive, and the active power reference value P refThe Pf decrease characteristic curve shifts upward, and the output active power remains unchanged while the frequency increases. In summary, the above control strategy can make the frequency output by the energy storage vehicle gradually approach the diesel engine frequency.

[0103] 3) Phase controller

[0104] The phase of the output voltage of the virtual synchronous machine is determined by the integral of the initial phase and frequency. The frequency is regulated by the frequency controller, so the phase controller mainly controls the initial phase of the output voltage of the energy storage vehicle. The phase difference between the energy storage vehicle and the diesel engine is input into the PI controller. When the phase of the energy storage vehicle is higher than that of the diesel engine, the output of the PI controller is negative, and the initial phase of the energy storage vehicle output is reduced; when the phase of the energy storage vehicle is lower than that of the diesel engine, the output of the PI controller is positive, and the initial phase of the energy storage vehicle output increases, making the initial phase of the energy storage vehicle and the diesel engine the same. At the same time, since the frequency is controlled by the frequency controller, the difference is very small, so the phase of the energy storage vehicle and the diesel engine is basically the same.

[0105] By adding three control links, namely voltage amplitude controller, frequency controller and voltage phase controller, on the basis of virtual synchronous generator control, after turning on the pre-synchronization switch for a period of time, the output voltage amplitude, frequency and phase of the energy storage vehicle can be consistent with those of the diesel generator, meeting the pre-synchronization conditions for synchronous parallel operation.

[0106] C. Virtual synchronous machine pre-synchronization and grid connection control strategy

[0107] After the mobile energy storage vehicle completes the parallel power supply with the diesel generator, it often needs to be connected to the grid so that the grid after maintenance can supply power to the load again. In order to ensure the safe and stable grid connection process of the diesel storage parallel system, the voltage amplitude, frequency and phase consistency between the parallel system and the grid must be met. In order to meet the three conditions of grid synchronization, a set of voltage amplitude controllers and frequency controllers are added on the basis of the original parallel virtual synchronous machine control, and a controller switching switch is added, and a secondary frequency regulation controller is added to adjust the phase between the parallel system and the grid.

[0108] 1) Amplitude and frequency regulator switching strategy

[0109] The grid-connected amplitude and frequency regulators act on the reactive-voltage control part of the stator electrical characteristic equation equivalent control model and the active power reference value of the rotor mechanical characteristic equation equivalent control model respectively. The principle is roughly the same as that of the parallel-machine amplitude and frequency regulators, except that the synchronous generator frequency in the parallel-machine frequency regulator is replaced by the grid frequency. In order to avoid affecting the accuracy of control due to the participation of another group of regulators in the regulation during parallel or grid-connected pre-synchronization, it is necessary to add a switching control strategy between the parallel-machine regulator and the grid-connected regulator.

[0110] Switching control strategy such as Figure 3As shown in the figure, when the diesel-storage parallel system meets the following conditions, the stability signal SS output is 1, and the parallel system is stable and can be connected to the grid.

[0111]

[0112] Among them U 0 is the output voltage amplitude of the energy storage vehicle, U gen is the output voltage amplitude of the diesel engine, ΔU max The maximum voltage difference allowed to maintain system stability, ω 0 is the output frequency of the energy storage vehicle, ω gen is the diesel engine output frequency, Δω max The maximum frequency difference allowed, is the output voltage phase of the energy storage vehicle, is the diesel engine output voltage phase, The maximum phase difference allowed to keep the system stable.

[0113] When the SS output is 1, that is, the diesel-storage parallel system is stable, the grid-connected signal switch changes from 0 to 1, and the grid-connected pre-synchronization operation begins. The parallel amplitude and frequency regulators are closed, and the grid-connected amplitude and frequency regulators are opened to start synchronization with the grid side amplitude and frequency.

[0114] 2) Secondary frequency modulation controller

[0115] The parallel system of diesel and energy storage is different from the parallel system when it is connected to the grid. It may have a large phase difference when the parallel system is pre-synchronized. At this time, it is impossible to make the parallel system and the grid phase consistent by adjusting the initial phase. When the grid frequency controller adjusts the frequency to the same as the grid, the phase between the parallel system and the grid side will maintain a steady-state error that cannot be eliminated, and the error is usually large, which seriously affects the safe and stable operation of the grid. Therefore, it is necessary to perform secondary frequency modulation on the frequency of the parallel system to eliminate the phase difference between the parallel system and the grid.

[0116] The secondary frequency controller directly acts on the active power reference value of the rotor mechanical characteristic equation to adjust the frequency. When the parallel system frequency is consistent with the grid frequency, and the phase difference is still greater than the maximum phase error allowed by the grid, the secondary frequency controller starts to work and changes the frequency by adjusting the Pf drop characteristic curve. It should be pointed out that, unlike the parallel frequency regulation, when the parallel system frequency needs to rise, since the load has not changed, the sum of the power output by the energy storage vehicle and the diesel generator remains unchanged, and the control system cannot control the Pf drop characteristic curve of the diesel generator. Therefore, when the parallel system frequency rises, the active power output of the diesel generator must decrease, and the active power output of the energy storage vehicle should increase to keep the system stable at this frequency. Therefore, when the parallel system frequency is lower than the grid frequency, the output of the secondary frequency controller is positive, the Pf drop characteristic curve shifts upward, and the parallel system frequency increases; when the parallel system frequency is higher than the grid frequency, the output of the secondary frequency controller is negative, the Pf drop characteristic curve shifts downward, and the parallel system frequency decreases.

[0117] 3) Virtual synchronous machine parallel connection and grid connection control process

[0118] The specific process of virtual synchronous machine controlling energy storage vehicle to realize pre-synchronization of parallel operation and grid connection is as follows:

[0119] (1) The energy storage vehicle is started, and the virtual synchronous machine control moment of inertia J, damping coefficient D, and active power reference value P are set. ref and reactive power reference value Q ref , the virtual synchronous machine controls the output control signal to control the inverter output voltage.

[0120] (2) The parallel signal jumps from 0 to 1, and the parallel voltage, frequency and phase controllers are connected to the control system.

[0121] (3) After the parallel voltage, frequency and phase controllers are added to the control, the virtual synchronous machine control output control signal changes, the voltage, frequency and phase at the parallel point are consistent with the voltage, frequency and phase of the diesel generator, and the parallel operation is completed by closing the switch.

[0122] (4) After the parallel system is stable, the stability signal jumps from 0 to 1.

[0123] (5) When grid connection is required, the grid connection signal is stepped from 0 to 1, and the grid connection voltage and frequency controllers are connected to the control system.

[0124] (6) After the grid-connected voltage and frequency controllers are added to the control, the virtual synchronous machine control output control signal changes, and the voltage and frequency of the grid-connected point are consistent with the voltage and frequency of the grid.

[0125] (7) The secondary frequency controller is connected to the control system, and the frequency controller is temporarily disconnected from the control system. After the phase of the grid connection point is consistent with the grid phase, the secondary frequency controller is disconnected from the control system and the frequency controller is reconnected to the control system. After the grid connection point frequency is consistent with the grid frequency, the switch is closed to complete the grid connection.

[0126] The present invention conducts simulation experiments based on the data of energy storage vehicles and diesel engines on the Simulink simulation platform of Matlab. A multi-type mobile power resource parallel control method based on virtual synchronous generators verifies the effectiveness of the proposed method.

[0127] The main parameters used in the simulation model of this scheme are as follows: the voltage level is 380V, the DC side output voltage of the energy storage vehicle is 700V, the output voltage of the diesel generator is 380V, the load active power is 200kW, the rated voltage of the infinite grid is 380V, the rated frequency is 50Hz, the initial phase angles of the energy storage vehicle, diesel generator and grid are all 0, parallel connection is started at the beginning of the simulation, and the grid connection signal step is performed after 1s of simulation.

[0128] pass Figure 4 and Figure 5 As a result, the control strategy of this scheme can effectively complete the parallel operation and the grid-connected operation after parallel operation, and control the parallel voltage and phase error to be close to 0, and the frequency error to be controlled within 0.5% of the rated frequency; it can control the grid voltage to be close to 0, the frequency error to be within 0.5% of the rated frequency, and adjust the larger phase error to close to 0. This simulation experiment verifies the stability and effectiveness of the parallel and grid-connected control strategy of this scheme.

[0129] A mobile power resource parallel machine and grid control system, comprising:

[0130] Virtual synchronous generator model, used to simulate the damping and inertia characteristics, active frequency regulation and reactive voltage regulation characteristics of synchronous generators, so that the output characteristics of the energy storage system are similar to those of synchronous generators;

[0131] Parallel controller, used to parallel the diesel generator vehicle and the mobile energy storage vehicle;

[0132] A grid-connected controller is used to connect the parallel system to the power grid;

[0133] The controller switch is used to switch between the parallel controller and the grid-connected controller.

[0134] The virtual synchronous generator model comprises:

[0135] The rotor mechanical characteristic equation equivalent control module is used to simulate the mechanical characteristics of the synchronous generator rotor. Its input is the mechanical power P of the virtual synchronous generator. m and the electromagnetic power P of the virtual synchronous generator e, and take the moment of inertia J and damping coefficient D as parameters, and output the electrical angular velocity ω, which satisfies:

[0136]

[0137] Among them, P m is the mechanical power of the virtual synchronous generator, P e is the electromagnetic power of the virtual synchronous generator, ω is the electrical angular velocity of the virtual synchronous generator, ω n is the rated electrical angular velocity, the active power reference value P of the virtual synchronous generator ref As mechanical power P m , the active power at the grid-connected node is taken as the electromagnetic power P e ;

[0138] Stator electrical characteristic equation equivalent control module is used to simulate the stator electrical characteristics of the synchronous generator. Its input is the armature terminal voltage of the virtual synchronous generator. and the armature current of the virtual synchronous generator And the armature resistance R a and synchronous reactance X s As a parameter, the output is the armature terminal voltage of the virtual synchronous generator It satisfies:

[0139]

[0140] in, is the excitation electromotive force of the virtual synchronous generator, the phase angle θ obtained by integrating the electrical angular velocity ω and the excitation electromotive force amplitude E of the virtual synchronous generator 0 Combined to obtain, is the armature terminal voltage of the virtual synchronous generator, is the armature current of the virtual synchronous generator, R a is the armature resistance, X s is the synchronous reactance.

[0141] The parallel controller comprises:

[0142] The parallel voltage amplitude controller is used to control the voltage parameter Un. When the output voltage amplitude of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the voltage reference value of the virtual synchronous generator of the mobile energy storage vehicle is reduced; otherwise, its voltage reference value is increased until the output voltage amplitude of the mobile energy storage vehicle is equal to the voltage amplitude of the diesel generator vehicle;

[0143] The parallel frequency controller is used to control the parallel voltage frequency. When the output voltage frequency of the mobile energy storage vehicle is higher than the voltage frequency of the diesel generator vehicle, the controller output is a negative value, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the voltage frequency of the diesel generator vehicle, the controller output is a positive value, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases;

[0144] The parallel voltage phase controller is used to control the parallel voltage phase. When the output voltage phase of the mobile energy storage vehicle is higher than that of the diesel generator vehicle, the controller output is negative and the initial phase of the energy storage vehicle output is reduced; when the output voltage phase of the mobile energy storage vehicle is lower than that of the diesel generator vehicle, the controller output is positive and the initial phase of the energy storage vehicle output is increased, so that the energy storage vehicle and the diesel generator vehicle have the same phase.

[0145] The grid-connected controller comprises:

[0146] The grid-connected voltage amplitude controller is used to control the voltage parameter Un. When the output voltage amplitude of the mobile energy storage vehicle is higher than the grid voltage amplitude, the voltage reference value of the virtual synchronous generator of the mobile energy storage vehicle is reduced; otherwise, its voltage reference value is increased until the output voltage amplitude of the mobile energy storage vehicle is equal to the voltage amplitude;

[0147] The grid-connected voltage frequency controller is used to control the grid-connected voltage frequency. When the output voltage frequency of the mobile energy storage vehicle is higher than the grid voltage frequency, the controller output is a negative value, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the grid voltage frequency, the controller output is a positive value, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases;

[0148] The grid-connected voltage secondary frequency regulation controller is used to control the grid-connected voltage phase. When the output voltage phase of the mobile energy storage vehicle is lower than the grid phase, the controller output is positive, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output voltage phase of the mobile energy storage vehicle is equal to the grid phase; when the output voltage phase of the mobile energy storage vehicle is higher than the grid phase, the controller output is negative, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases until the output voltage phase of the mobile energy storage vehicle is equal to the grid phase.

[0149] The controller switch switching steps are as follows:

[0150] Read the voltage amplitude, frequency and phase difference between the mobile energy storage vehicle and the diesel generator vehicle;

[0151] Based on the following conditions, it is determined that the parallel system of the mobile energy storage vehicle and the diesel generator vehicle has been stabilized;

[0152]

[0153] After the parallel system of the mobile energy storage vehicle and the diesel generator vehicle is stable, the controller switch is switched from the parallel regulation side to the grid-connected regulation side to complete the switching of the controller.

[0154] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements any one of the aforementioned methods for controlling parallel operation and grid connection of multiple types of mobile power resources based on a virtual synchronous generator.

[0155] A computer-readable storage medium having a computer program stored thereon, wherein the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute any of the aforementioned methods for controlling parallel operation and grid connection of multiple types of mobile power resources based on a virtual synchronous generator.

[0156] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0157] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0158] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0159] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0160] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0161] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A mobile power resource parallel connection and grid connection control method, the control method is used to parallel connection and grid connection of power resources between a mobile energy storage vehicle and a diesel generator vehicle in operation, characterized in that: The following steps are included: Start the mobile energy storage vehicle and read the control moment of inertia J, damping coefficient D, and active power reference value P of the synchronous generator on the mobile energy storage vehicle. ref and reactive power reference value Q ref , a virtual synchronous generator model is constructed through the moment of inertia, damping coefficient, active power reference value, and reactive power reference value; Read the amplitude, frequency and phase information of the voltage of the diesel generator car, and control the amplitude, frequency and phase of the output voltage of the mobile energy storage car through the virtual synchronous generator, so that they are consistent with the amplitude, frequency and phase of the output voltage of the diesel generator car, respectively, close the diesel generator car and the mobile energy storage car to complete the parallel operation, and form a parallel system with the diesel generator car and the mobile energy storage car; After the parallel system is stable, the voltage frequency and amplitude of the parallel system are synchronized with the voltage frequency and amplitude of the power grid through the virtual synchronous generator model, so that the voltage amplitude and frequency of the grid connection point are consistent with the voltage amplitude and frequency of the grid, and the parallel system and the grid are closed to complete the grid connection.

2. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: The virtual synchronous generator model includes a rotor mechanical characteristic equation equivalent control module and a stator electrical characteristic equation equivalent control module, and the rotor mechanical characteristic equation equivalent control module and the stator electrical characteristic equation equivalent control module jointly generate a signal to control the output voltage of the mobile energy storage vehicle; The input of the rotor mechanical characteristic equation equivalent control module is the mechanical power P of the virtual synchronous generator. m and the electromagnetic power P of the virtual synchronous generator e , and taking the moment of inertia, and the damping coefficient D as parameters, the output of the rotor mechanical characteristic equation equivalent control module is the electrical angular velocity ω, which satisfies: Among them, P m is the mechanical power of the virtual synchronous generator, P e is the electromagnetic power of the virtual synchronous generator, ω is the electrical angular velocity of the virtual synchronous generator, ω n is the rated electrical angular velocity, the active power reference value P of the virtual synchronous generator ref As mechanical power P m , the active power at the grid-connected node is taken as the electromagnetic power P e ; The stator electrical characteristic equation equivalent control module satisfies: in, is the excitation electromotive force of the virtual synchronous generator, which is obtained by combining the phase angle θ obtained by integrating the electrical angular velocity ω and the excitation electromotive force amplitude E0 of the virtual synchronous generator. is the armature terminal voltage of the virtual synchronous generator, is the armature current of the virtual synchronous generator, R a is the armature resistance, X s is the synchronous reactance.

3. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: The specific steps of controlling the amplitude, frequency and phase of the output voltage of the mobile energy storage vehicle by using a virtual synchronous generator are as follows: The electrical angular velocity ω is obtained by the rotor mechanical characteristic equation equivalent control module, and the electrical angular velocity ω is passed through an integrator to obtain a phase angle θ. The reactive power at the grid-connected node is read and the reactive power reference value is set to obtain an excitation electromotive force amplitude E0. The excitation electromotive force of phase A is obtained by taking E0 as the amplitude and θ as the phase angle. The excitation electromotive force of phase A is lagged by 120° and 240° respectively to obtain the excitation electromotive force of phase B and phase C. The excitation electromotive force is obtained by synthesizing the three phases A, B and C. According to the stator electrical characteristic equation equivalent control module, the armature resistance R of the synchronous generator is a and synchronous reactance X s The sum of the armature current of the virtual synchronous generator Multiply them together to get the stator voltage drop; The armature terminal voltage of the virtual synchronous generator is obtained by subtracting the excitation electromotive force from the stator voltage drop. The voltage command is obtained through voltage and current dual closed-loop control, and a PWM signal is generated to control the amplitude, frequency and phase of the output voltage of the mobile energy storage vehicle.

4. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: The control of the output voltage amplitude of the mobile energy storage vehicle is achieved by changing its voltage reference value Un. When the output voltage amplitude of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the voltage reference value of the mobile energy storage vehicle is reduced, otherwise the voltage reference value is increased until the output voltage amplitude of the mobile energy storage vehicle is equal to the voltage amplitude of the diesel generator vehicle.

5. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: The virtual synchronous generator model controls the output voltage frequency of the mobile energy storage vehicle by changing its active power reference value, namely the pf drop characteristic curve. When the output voltage frequency of the mobile energy storage vehicle is higher than the voltage frequency of the diesel generator vehicle, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the voltage frequency of the diesel generator vehicle, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output voltage frequency of the mobile energy storage vehicle is equal to the output voltage frequency of the diesel generator vehicle.

6. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: The virtual synchronous generator model changes the output voltage phase of the mobile energy storage vehicle by changing its initial output voltage phase. When the output voltage phase of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the initial output voltage phase of the mobile energy storage vehicle is reduced, otherwise the initial output voltage phase is increased until the output voltage phase of the mobile energy storage vehicle is the same as that of the diesel generator vehicle.

7. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: When the following conditions are met, the parallel system is considered stable: Where U0 is the output voltage amplitude of the mobile energy storage vehicle, U gen is the output voltage amplitude of the diesel generator car, ΔU max To maintain the maximum voltage difference allowed for system stability, ω0 is the output frequency of the mobile energy storage vehicle, ω gen is the output frequency of the diesel generator, Δω max The maximum frequency difference allowed to maintain system stability is: Output voltage phase of mobile energy storage vehicle, is the output voltage phase of the diesel generator car, The maximum phase difference allowed to keep the system stable.

8. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: Before the parallel system is connected to the grid, the following steps are also required: The voltage amplitude between the parallel system and the power grid is adjusted by adjusting the voltage reference value Un of the mobile energy storage vehicle in the parallel system. Specifically, when the output voltage amplitude of the parallel system is higher than the voltage amplitude of the power grid, the voltage reference value of the mobile energy storage vehicle is reduced; when the output voltage amplitude of the parallel system is lower than the voltage amplitude of the power grid, its voltage reference value is increased until the output voltage amplitude of the parallel system is equal to the voltage amplitude of the power grid.

9. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: Before the parallel system is connected to the grid, the following steps are also required: The frequency between the parallel system and the power grid is adjusted by adjusting the active power reference value of the mobile energy storage vehicle in the parallel system, that is, the pf drop characteristic curve. Specifically, when the output voltage frequency of the mobile energy storage vehicle is higher than the grid voltage frequency, the controller output is a negative value, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the grid voltage frequency, the controller output is a positive value, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output frequency of the parallel system is equal to the grid frequency.

10. A mobile power resource parallel connection and grid connection control method according to claim 1, characterized in that: Before the parallel system is connected to the grid, the following steps are also required: When the frequency of the parallel system is equal to that of the grid, and the phase of the parallel system is not equal to that of the grid, the phase between the parallel system and the grid is adjusted. This is achieved by adjusting the active power reference value of the mobile energy storage vehicle in the parallel system, i.e., the pf drop characteristic curve, to control the frequency difference between the parallel system and the grid. Specifically, when the phase of the parallel system is lower than the phase of the grid, the Pf drop characteristic curve is shifted upward so that the frequency of the parallel system is greater than the grid frequency, and the phase of the parallel system increases relative to the phase of the grid; when the phase of the parallel system is greater than the phase of the grid, the Pf drop characteristic curve is shifted downward so that the frequency of the parallel system is less than the grid frequency, and the phase of the parallel system decreases relative to the phase of the grid, until the phase of the parallel system is equal to the phase of the grid.

11. A mobile power resource parallel machine and grid control system, characterized in that: include: Model building module, used to start the mobile energy storage vehicle and read the control moment of inertia J, damping coefficient D, and active power reference value P of the synchronous generator on the mobile energy storage vehicle ref and reactive power reference value Q ref , a virtual synchronous generator model is constructed through the moment of inertia, damping coefficient, active power reference value, and reactive power reference value; The parallel module is used to read the amplitude, frequency and phase information of the diesel generator vehicle voltage, and control the amplitude, frequency and phase of the mobile energy storage vehicle output voltage through the virtual synchronous generator to make them consistent with the amplitude, frequency and phase of the diesel generator vehicle output voltage, and close the diesel generator vehicle and the mobile energy storage vehicle to complete the parallel operation, forming a parallel system with the diesel generator vehicle and the mobile energy storage vehicle. The grid-connected module is used to synchronize the voltage frequency and amplitude of the parallel system with the voltage frequency and amplitude of the power grid through a virtual synchronous generator model after the parallel system is stable, so that the voltage amplitude and frequency of the grid-connected point are consistent with the voltage amplitude and frequency of the power grid, and the parallel system and the power grid are closed to complete the grid connection.

12. A mobile power resource parallel machine and grid control system according to claim 11, characterized in that: The model building module includes: The rotor mechanical characteristic equation equivalent control module is used to simulate the mechanical characteristics of the synchronous generator rotor. Its input is the mechanical power P of the virtual synchronous generator. m and the electromagnetic power P of the virtual synchronous generator e , and take the moment of inertia J and damping coefficient D as parameters, and output the electrical angular velocity ω, which satisfies: Among them, P m is the mechanical power of the virtual synchronous generator, P e is the electromagnetic power of the virtual synchronous generator, ω is the electrical angular velocity of the virtual synchronous generator, ω n is the rated electrical angular velocity, the active power reference value P of the virtual synchronous generator ref As mechanical power P m , the active power at the grid-connected node is taken as the electromagnetic power P e ; Stator electrical characteristic equation equivalent control module is used to simulate the stator electrical characteristics of the synchronous generator. Its input is the armature terminal voltage of the virtual synchronous generator. and the armature current of the virtual synchronous generator And the armature resistance R a and synchronous reactance X s As a parameter, the output is the armature terminal voltage of the virtual synchronous generator It satisfies: in, is the excitation electromotive force of the virtual synchronous generator, which is obtained by combining the phase angle θ obtained by integrating the electrical angular velocity ω and the excitation electromotive force amplitude E0 of the virtual synchronous generator. is the armature terminal voltage of the virtual synchronous generator, is the armature current of the virtual synchronous generator, R a is the armature resistance, X s is the synchronous reactance.

13. A mobile power resource parallel and grid-connected control system according to claim 11, characterized in that: The specific steps of the parallel module controlling the amplitude, frequency and phase of the output voltage of the mobile energy storage vehicle are as follows: The electrical angular velocity ω is obtained by the rotor mechanical characteristic equation equivalent control module, and the electrical angular velocity ω is passed through an integrator to obtain a phase angle θ. The reactive power at the grid-connected node is read and the reactive power reference value is set to obtain an excitation electromotive force amplitude E0. The excitation electromotive force of phase A is obtained by taking E0 as the amplitude and θ as the phase angle. The excitation electromotive force of phase A is lagged by 120° and 240° respectively to obtain the excitation electromotive force of phase B and phase C. The excitation electromotive force is obtained by synthesizing the three phases A, B and C. According to the stator electrical characteristic equation equivalent control module, the armature resistance R of the synchronous generator is a and synchronous reactance X s The sum of the armature current of the virtual synchronous generator Multiply them together to get the stator voltage drop; The armature terminal voltage of the virtual synchronous generator is obtained by subtracting the excitation electromotive force from the stator voltage drop. The voltage command is obtained through voltage and current dual closed-loop control, and a PWM signal is generated to control the amplitude, frequency and phase of the output voltage of the mobile energy storage vehicle.

14. A mobile power resource parallel and grid-connected control system according to claim 11, characterized in that: The parallel module controls the output voltage amplitude of the mobile energy storage vehicle by changing its voltage reference value Un. When the output voltage amplitude of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the voltage reference value of the mobile energy storage vehicle is reduced, otherwise the voltage reference value is increased until the output voltage amplitude of the mobile energy storage vehicle is equal to the voltage amplitude of the diesel generator vehicle.

15. A mobile power resource parallel and grid-connected control system according to claim 11, characterized in that: The parallel module controls the output voltage frequency of the mobile energy storage vehicle by changing its active power reference value, i.e., the pf drop characteristic curve. When the output voltage frequency of the mobile energy storage vehicle is higher than the voltage frequency of the diesel generator vehicle, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the voltage frequency of the diesel generator vehicle, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output voltage frequency of the mobile energy storage vehicle is equal to the output voltage frequency of the diesel generator vehicle.

16. A mobile power resource parallel and grid-connected control system according to claim 11, characterized in that: The parallel module changes the output voltage phase of the mobile energy storage vehicle by changing its initial output voltage phase. When the output voltage phase of the mobile energy storage vehicle is higher than the voltage amplitude of the diesel generator vehicle, the initial output voltage phase of the mobile energy storage vehicle is reduced, otherwise the initial output voltage phase is increased until the output voltage phase of the mobile energy storage vehicle is the same as that of the diesel generator vehicle.

17. A mobile power resource parallel and grid-connected control system according to claim 11, characterized in that: The parallel module determines that the parallel system is stable when the following conditions are met: Where U0 is the output voltage amplitude of the mobile energy storage vehicle, U gen is the output voltage amplitude of the diesel generator car, ΔU max To maintain the maximum voltage difference allowed for system stability, ω0 is the output frequency of the mobile energy storage vehicle, ω gen is the output frequency of the diesel generator, Δω max The maximum frequency difference allowed to maintain system stability is: Output voltage phase of mobile energy storage vehicle, is the output voltage phase of the diesel generator car, The maximum phase difference allowed to keep the system stable.

18. A mobile power resource parallel and grid-connected control system according to claim 11, characterized in that: The grid-connected control module adjusts the voltage amplitude between the parallel system and the power grid by adjusting the voltage reference value Un of the mobile energy storage vehicle in the parallel system. Specifically, when the output voltage amplitude of the parallel system is higher than the voltage amplitude of the power grid, the voltage reference value of the mobile energy storage vehicle is reduced; when the output voltage amplitude of the parallel system is lower than the voltage amplitude of the power grid, its voltage reference value is increased until the output voltage amplitude of the parallel system is equal to the voltage amplitude of the power grid.

19. A mobile power resource parallel machine and grid control system according to claim 11, characterized in that: The grid-connected control module adjusts the frequency between the parallel system and the power grid by adjusting the active power reference value of the mobile energy storage vehicle in the parallel system, that is, the pf drop characteristic curve. Specifically, when the output voltage frequency of the mobile energy storage vehicle is higher than the grid voltage frequency, the controller output is a negative value, the Pf drop characteristic curve shifts downward, and the output voltage frequency of the mobile energy storage vehicle decreases; when the output voltage frequency of the mobile energy storage vehicle is lower than the grid voltage frequency, the controller output is a positive value, the Pf drop characteristic curve shifts upward, and the output voltage frequency of the mobile energy storage vehicle increases until the output frequency of the parallel system is equal to the grid frequency.

20. A mobile power resource parallel and grid-connected control system according to claim 11, characterized in that: The grid-connected control module adjusts the phase between the parallel system and the grid by adjusting the active power reference value of the mobile energy storage vehicle in the parallel system, that is, the pf drop characteristic curve to control the frequency difference between the parallel system and the grid. Specifically, when the phase of the parallel system is lower than the phase of the grid, the Pf drop characteristic curve is shifted upward so that the frequency of the parallel system is greater than the grid frequency, and the phase of the parallel system increases relative to the grid phase; when the phase of the parallel system is greater than the grid phase, the Pf drop characteristic curve is shifted downward so that the frequency of the parallel system is less than the grid frequency, and the phase of the parallel system decreases relative to the grid phase until the phase of the parallel system is equal to the grid phase.

21. A computer device, characterized in that: It includes a memory and a processor, the memory stores a computer program, and is characterized in that the memory stores the computer program, and when the processor executes the computer program, it implements a method for controlling parallel operation and grid connection of multiple types of mobile power resources based on a virtual synchronous generator as described in any one of claims 1 to 10.

22. A computer-readable storage medium having a computer program stored thereon, characterized in that: The storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute a method for controlling parallel operation and grid connection of multiple types of mobile power resources based on a virtual synchronous generator as described in any one of claims 1 to 10.

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