Dynamic configuration method of multi-machine parameters in emergency power supply system of multi-vehicle-pile unit area

Abstract

The present invention relates to the technical field of electric vehicle charging equipment, and in particular to a method for dynamically configuring multi-machine parameters of a multi-vehicle pile unit area emergency power supply system, the method comprising the following steps: reusing a bidirectional charging pile as an area emergency power supply; adopting a multi-vehicle multi-pile networking control strategy to supply power to the area load when the power grid is out of power; introducing an instantaneous power adjustment coefficient module into the multi-vehicle multi-pile networking control strategy, and the main control system calculates the instantaneous power output capacity of the vehicle pile unit based on the real-time status information of the vehicle battery obtained by the vehicle pile unit through the vehicle pile communication system, and then calculates and dynamically adjusts the instantaneous power adjustment coefficient of the channel where the vehicle pile unit is located. In the new scenario of reusing a bidirectional charging pile as an emergency power supply and networking of multiple vehicle pile units, the present invention provides a strategy for dynamically adjusting the instantaneous power adjustment coefficient of the channel where each vehicle pile unit is located, thereby reasonably and dynamically allocating the impact load power between each vehicle pile unit to avoid the power exceeding the limit of individual vehicle pile units.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle charging equipment, and in particular to a method for dynamically configuring parameters of multiple machines in an emergency power supply system of a multi-vehicle pile unit area. Background Art

[0002] With the popularity of electric vehicles, the technical concept of vehicle-to-grid bidirectional power interaction (V2G) has emerged. Its core content is to use the battery units of new energy electric vehicles as large-scale distributed energy storage units of the power grid, and participate in the operation of the power system to achieve bidirectional interaction of energy between the power grid and the vehicle, with the aim of improving the power load curve of the power system and reducing the actual operating pressure of the power grid. Specifically, V2G can balance the load of the power system, charge electric vehicles during the valley power period at night based on time-of-use electricity prices, and feed back energy to the power grid according to demand during the peak power period during the day, thus achieving peak shifting and valley filling.

[0003] On the one hand, although the V2G bidirectional charging and discharging between electric vehicles and the power grid has completed successful demonstration operation in a series of national projects, it has encountered serious economic bottlenecks in its promotion and application. Specifically, it is intolerable for users of high-power fast charging piles to hang the car on the charging pile for a long time to charge and discharge during peak-filling periods. They all need to have a charging waiting time close to the experience of fast refueling of traditional cars. Moreover, compared with the expensive battery cost, the depreciation cost of the battery's charge and discharge cycle life caused by V2G cannot be recovered through the peak-valley price difference. These two major economic bottlenecks have severely restricted the real promotion of V2G. Therefore, vehicle-grid interaction requires other practical forms and corresponding technologies besides V2G.

[0004] On the other hand, in the existing emergency power supply scheme for urban substations, diesel generators or mobile power emergency vehicles are most commonly used. After a power outage occurs, the corresponding power staff usually disconnects the connection switch between the power supply substation and the mains in the distribution cabinet, and then starts the diesel generator or notifies the mobile power emergency vehicle to continue to supply power to the load of the power supply substation as a backup power supply. The time required for diesel generators or mobile power emergency vehicles to restore power is generally relatively long, and the area occupied by diesel generators is relatively large. In addition to the generator set, it is also necessary to consider the control, power distribution, fuel tank and other auxiliary equipment rooms, which have high requirements for plane and space. In addition, the oil storage room itself is a fire hazard, so it also needs to be fireproofed. Therefore, compared with V2G, reusing bidirectional charging piles as emergency power supplies to replace diesel generators has greater development prospects.

[0005] However, in this new scenario of reusing bidirectional charging piles as emergency power supplies, there are still some technical problems. That is, the multiple bidirectional charging piles in the power station and their corresponding power conversion systems have formed an emergency power supply engineering problem of combining multiple bidirectional charging piles and vehicle pile units with small granularity to form a network. One of the biggest technical challenges is the parameter matching problem between the networking control of bidirectional charging piles and vehicle pile units of each granularity. If the parameters are not well matched, it will cause uneven instantaneous power distribution between multiple bidirectional charging piles and vehicle piles when the emergency power supply load changes suddenly, causing the power of individual bidirectional charging piles and vehicle piles to exceed the limit. Therefore, a method for dynamic configuration of parameters between multiple bidirectional charging piles and vehicle piles is needed. Summary of the invention

[0006] In view of the defects in the prior art, the present invention provides a method for dynamically configuring multi-machine parameters of a multi-vehicle pile unit area emergency power supply system.

[0007] In order to achieve the above-mentioned purpose, the present invention provides a multi-machine parameter dynamic configuration method for a multi-vehicle-pile unit substation emergency power supply system, the method comprising the following steps: constructing a topology and control architecture for reusing a bidirectional charging pile as an emergency power supply for the substation; when the power grid is out of power, based on the topology and control architecture, the bidirectional charging pile vehicle-pile unit adopts a multi-vehicle and multi-pile networking control strategy to construct a microgrid, and the load switch is closed to supply power to the substation load; the main control system in the charging station calculates the instantaneous power output capacity of the bidirectional charging pile vehicle-pile unit according to the real-time status information of the vehicle battery obtained by the bidirectional charging pile vehicle-pile unit through the vehicle-pile communication system; an instantaneous power regulation coefficient module is introduced into the multi-vehicle and multi-pile networking control strategy, and then the initial value of the instantaneous power regulation coefficient of the channel where the bidirectional charging pile vehicle-pile unit is located is set according to the stability constraint condition; based on the instantaneous power output capacity, combined with the control law between the impact load power and the instantaneous power regulation coefficient of each of the bidirectional charging pile vehicle-pile units, the instantaneous power regulation coefficient of the channel where the bidirectional charging pile vehicle-pile unit is located is dynamically adjusted. In a new scenario where a bidirectional charging pile is reused as an emergency power supply and multiple bidirectional charging pile vehicle-pile units are networked, the present invention provides a strategy for dynamically adjusting the instantaneous power adjustment coefficient of the channel where each bidirectional charging pile vehicle-pile unit is located, so as to reasonably and dynamically distribute the impact load power among the bidirectional charging pile vehicle-pile units and avoid the power exceeding the limit of individual bidirectional charging pile vehicle-pile units.

[0008] Optionally, the construction of a topology and control architecture for reusing the bidirectional charging pile vehicle pile unit as an emergency power supply for the station area includes the following steps:

[0009] Constructing a cascade power conversion system for a bidirectional charging pile, and constructing a power supply circuit for connecting the cascade power conversion system, the power grid and the load in the station area;

[0010] The power supply circuit is used to interconnect the cascade power conversion system, the power grid and the substation load to form the topology and control architecture.

[0011] Optionally, the cascade power conversion system includes a grid-side inverter and a pile-side converter of each of the bidirectional charging pile vehicle pile units, and the power supply circuit includes a three-wire AC bus, an isolation transformer, a load switch, a transfer switch, a four-wire AC bus, a grid-side switch and a load bus;

[0012] The grid-side inverter and the pile-side converter are cascaded via a common DC bus;

[0013] The three-phase AC sides of the plurality of grid-side inverters are connected in parallel and connected to one side of the triangle of the isolation transformer;

[0014] The grid-side switch and the load switch are both three-phase four-wire, the two ends of the grid-side switch are respectively connected to the grid and the load bus, and the two ends of the load switch are respectively connected to the load bus and the three-phase four-wire of the star side of the isolation transformer;

[0015] The switching switch is a three-phase three-wire switch, and two ends of the switching switch are respectively connected to one side of the triangle of the isolation transformer and the load bus.

[0016] Optionally, when the power grid is out of power, based on the topology and control architecture, a plurality of the bidirectional charging pile vehicle pile units adopt a multi-vehicle multi-pile network control strategy to construct a microgrid, and the load switch is closed to supply power to the load in the substation, including the following steps:

[0017] When the power grid is out of power, sampling the current input to the isolation transformer and the output filter capacitor voltage of the grid-side inverter;

[0018] Based on the sampling results, the instantaneous active power and instantaneous reactive power are calculated using the instantaneous power calculation module;

[0019] The instantaneous active power and the instantaneous reactive power are input into a network control module, and the network control module outputs a voltage amplitude and an angle signal to a voltage generation module;

[0020] Use the voltage generation module to generate a dq axis voltage control instruction, and input the difference between the dq axis voltage control instruction and the dq coordinate system transformation result of the output filter capacitor voltage into the voltage and current inner loop;

[0021] The voltage and current inner loop generates an output voltage dq coordinate axis instruction of the grid-side inverter, and then converts it into an output voltage instruction of a three-phase coordinate system through coordinate system transformation;

[0022] The output voltage instruction is input into a PWM modulation module to generate a high-frequency switching signal for the grid-side inverter.

[0023] Optionally, the input of the instantaneous power adjustment coefficient module is the d-axis component and q-axis component of the current of the isolation transformer in the synchronous rotating coordinate system, and the output of the voltage generation module is subtracted from the output of the instantaneous power adjustment coefficient module to obtain a modified dq-axis voltage control instruction, and the modified dq-axis voltage control instruction is subtracted from the dq coordinate system transformation result of the output filter capacitor voltage and input into the voltage and current inner loop.

[0024] Optionally, the modified dq axis voltage control command satisfies the following relationship:

[0025]

[0026] in, and are respectively the d-axis component and the q-axis component in the modified dq-axis voltage control instruction corresponding to the i-th bidirectional charging pile vehicle pile unit; u c_drefi and u c_qrefi are respectively the d-axis component and the q-axis component in the dq-axis voltage control instruction generated by the voltage generation module corresponding to the i-th bidirectional charging pile vehicle pile unit; i 2di and i 2qi are respectively the d-axis component and the q-axis component of the current input to the isolation transformer corresponding to the i-th bidirectional charging pile vehicle pile unit in the synchronous rotating coordinate system; X vi is the instantaneous power adjustment coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit; i=1, 2, 3, ..., N and N is the total number of the bidirectional charging pile vehicle pile units.

[0027] Optionally, in the multi-vehicle multi-pile network control strategy, the core control law between the active power setting, load power and output active power corresponding to each of the bidirectional charging pile vehicle-pile units is as follows:

[0028]

[0029] Among them, when i=j, When i≠j, K si and K sj is a symbol for E i is the output voltage amplitude of the i-th bidirectional charging pile vehicle pile unit; X vi is the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit; V is the grid side voltage; D piis the active power adjustment coefficient of the i-th bidirectional charging pile vehicle pile unit; E j is the output voltage amplitude of the j-th bidirectional charging pile vehicle pile unit, D pj is the active power adjustment coefficient of the j-th bidirectional charging pile vehicle pile unit, J 0j is the frequency time constant of the j-th bidirectional charging pile vehicle pile unit; T ij represents the control law of the power reference instruction of the j-th bidirectional charging pile vehicle pile unit on the power output of the i-th bidirectional charging pile vehicle pile unit; T iL is the control law of the load power on the power output of the i-th bidirectional charging pile vehicle pile unit; ΔP i is the instantaneous power output capacity of the i-th bidirectional charging pile vehicle pile unit; ΔP refi is the output power rating of the i-th bidirectional charging pile vehicle pile unit; ΔP load is the load power change of all the bidirectional charging pile vehicle pile units; i=1,2,3,...,N; j=1,2,3,...,N; N is the total number of the bidirectional charging pile vehicle pile units.

[0030] Optionally, the control law between the impact load power and the instantaneous power adjustment coefficient of each bidirectional charging pile vehicle pile unit is as follows:

[0031]

[0032] Among them, ΔP i (0) is the impact load power of the unit of the i-th pile, T ii represents the control law of the power reference instruction of the i-th bidirectional charging pile vehicle pile unit on the power output of the i-th bidirectional charging pile vehicle pile unit, T ij represents the control law of the power reference command of the j-th bidirectional charging pile vehicle pile unit on the power output of the i-th bidirectional charging pile vehicle pile unit, ΔP refi is the output power rating of the i-th bidirectional charging pile vehicle pile unit, ΔP load is the load power variation of all the bidirectional charging pile vehicle pile units, s is the Laplace operator, K si is a symbol for E i is the output voltage amplitude of the i-th bidirectional charging pile vehicle pile unit, X vi is the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle-pile unit, V is the grid-side voltage, i=1,2,3,...,N, j=1,2,3,...,N, N is the total number of the bidirectional charging pile vehicle-pile units.

[0033] Optionally, the stability constraint condition of the initial value of the instantaneous power regulation coefficient satisfies the following relationship:

[0034]

[0035] Among them, R i is the equivalent total output resistance of the i-th bidirectional charging pile vehicle pile unit, J 0i is the frequency time constant of the i-th bidirectional charging pile vehicle pile unit, D i is the damping coefficient of the i-th bidirectional charging pile vehicle pile unit, ω0 is the rated angular frequency of the bidirectional charging pile vehicle pile unit, U0 is the output phase voltage of the multi-vehicle multi-pile structure, U g is the voltage amplitude at the PCC in the multi-vehicle multi-pile structure, X Vi is the initial value of the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit, i=1,2,3,...,N, and N is the total number of the bidirectional charging pile vehicle pile units.

[0036] Optionally, the core control law between the dynamic adjustment amount of the instantaneous power regulation coefficient and the initial value of the instantaneous power regulation coefficient is as follows:

[0037]

[0038] Where ΔX vi is the dynamic adjustment amount of the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit, is the maximum instantaneous power of the i-th bidirectional charging pile vehicle-pile unit, U0 is the output phase voltage of the multi-vehicle multi-pile structure, and U g is the voltage amplitude at the PCC in the multi-vehicle multi-pile structure, is a symbol for E i is the output voltage amplitude of the i-th bidirectional charging pile vehicle pile unit, V is the grid side voltage, X Vi is the initial value of the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit, i=1,2,3,...,N, and N is the total number of the bidirectional charging pile vehicle pile units.

[0039] In summary, the present invention constructs a topology and control architecture that reuses bidirectional charging piles as emergency power supplies for substations, transforms bidirectional charging piles into multifunctional multiplexing equipment that provides emergency power supply, and mobilizes electric vehicles to connect to bidirectional charging piles for emergency power supply in substations when power outages occur in substations, thereby improving the disaster prevention and supply guarantee capabilities of urban power supply substations. At the same time, in the new scenario of transforming bidirectional charging piles into multifunctional multiplexing equipment that provides emergency power supply, the present invention dynamically adjusts the instantaneous power adjustment coefficient of the channel where each bidirectional charging pile vehicle pile unit is located by introducing an instantaneous power adjustment coefficient module, thereby reasonably and dynamically allocating the impact load power between each bidirectional charging pile vehicle pile unit, avoiding the power limit of individual bidirectional charging pile vehicle pile units, and ensuring the stability and safety of the bidirectional charging pile vehicle pile unit in providing emergency power supply to the substation load when the power grid is out of power. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 It is a flow chart of a method for dynamically configuring parameters of multiple machines in a multi-vehicle pile unit area emergency power supply system according to an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of the topology and control architecture of an embodiment of the present invention;

[0043] Figure 3 Schematic diagram of a multi-vehicle multi-pile network construction control strategy according to an embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of introducing an instantaneous power adjustment coefficient module into the multi-vehicle multi-pile network control strategy according to an embodiment of the present invention.

[0045] Among them: 1-power grid, 2-bidirectional charging pile vehicle-pile unit, 3-pile-side converter, 4-grid-side inverter, 5-three-wire AC bus, 6-isolation transformer, 7-load switch, 8-load bus, 9-switching switch, 10-station load, 11-four-wire AC bus, 12-grid-side switch, 13-multi-vehicle and multi-pile structure, 14-multi-mechanism network control structure. DETAILED DESCRIPTION

[0046] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details do not need to be adopted to implement the present invention. In other examples, in order to avoid confusing the present invention, known circuits, software or methods are not specifically described.

[0047] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or subcombination. In addition, it should be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale.

[0048] It should be noted in advance that, in an optional embodiment, except for independent explanations, the same symbols or letters appearing in all formulas have the same meanings and values.

[0049] In an alternative embodiment, see Figure 1 The present invention provides a method for dynamically configuring parameters of multiple machines in a multi-vehicle pile unit area emergency power supply system, the method comprising the following steps:

[0050] S1. Construct a topology and control architecture that reuses the bidirectional charging pile vehicle-pile unit as an emergency power supply for the station area.

[0051] Among them, S1 specifically includes the following steps:

[0052] S11, constructing a cascade power conversion system for a bidirectional charging pile, and at the same time constructing a power supply circuit for connecting the cascade power conversion system, the power grid and the load in the substation.

[0053] Specifically, in this embodiment, see Figure 2 The bidirectional charging pile vehicle pile unit 2 includes a grid-side inverter 4 and a pile-side converter 3. The cascade power conversion system includes multiple bidirectional charging pile vehicle pile units 2, and the three-phase AC sides of multiple grid-side inverters 4 are connected in parallel. The power supply circuit includes a three-wire AC bus 5, an isolation transformer 6, a load switch 7, the switching switch 9, a four-wire AC bus 11, a grid-side switch 12 and a load bus 8.

[0054] Furthermore, the pile-side converter 3 is a DC / DC converter, and the grid-side inverter 4 is an AC / DC converter, both of which are components of the bidirectional charging pile. The cascade power conversion system of this embodiment is a prior art and will not be described in detail here.

[0055] In other optional embodiments, the bidirectional charging pile vehicle pile unit 2 may also include an electric car connected to the bidirectional charging pile.

[0056] S12. Use the power supply circuit to interconnect the cascade power conversion system, the power grid and the substation load to form the topology and control architecture.

[0057] Specifically, in this embodiment, see Figure 2 , the grid-side inverter 4 and the pile-side converter 3 are cascaded through a common DC bus, the pile-side converter 3 is connected to the bidirectional charging pile vehicle pile unit 2 by a cable, and the three-phase AC sides of multiple grid-side inverters 4 are connected in parallel and connected to the delta side of the isolation transformer 6. The grid-side switch 12 and the load switch 7 are both three-phase four-wire, and the two ends of the grid-side switch 12 are respectively connected to the power grid 1 and the load bus 8, and the two ends of the load switch 7 are respectively connected to the load bus 8 and the three-phase four-wire on the star side of the isolation transformer 6. The switching switch 9 is three-phase three-wire, and the two ends of the switching switch 9 are respectively connected to the delta side of the isolation transformer 6 and the load bus 8. Multiple load feeders are used to connect the load bus 8 and the substation load 10.

[0058] The topology and control architecture of reusing bidirectional charging piles as emergency power supply for substations can also be called the substation emergency power supply system of bidirectional charging piles. By constructing the topology and control architecture of reusing bidirectional charging piles as emergency power supply for substations, the bidirectional charging piles are transformed into multifunctional multiplexing equipment for providing emergency power supply, breaking the application bottleneck of bidirectional charging pile vehicle-grid interaction V2G limited to shifting peaks and filling valleys, and can mobilize any electric vehicle and bidirectional charging pile to connect for substation emergency power supply when the power grid 1 is out of power, so that the emergency diesel generator set does not need to be installed to greatly improve the disaster prevention capacity of the urban power supply substation, and at the same time, it can also relieve the pressure of emergency power supply vehicles.

[0059] S2. When the power grid is out of power, based on the topology and control architecture, the bidirectional charging pile vehicle-pile unit adopts a multi-vehicle multi-pile network control strategy to build a microgrid, and the load switch is closed to supply power to the load in the substation.

[0060] Among them, see Figure 2 and Figure 3 , step S2 specifically includes the following steps:

[0061] S21. When the power grid is out of power, sampling the current input to the isolation transformer and the output filter capacitor voltage of the grid-side inverter.

[0062] More specifically, when the power grid 1 is out of power, the emergency power supply mode is switched to close the load switch 7, disconnect the grid-side switch 12 and the switching switch 9, and then the electric vehicle battery pack is used to provide off-grid emergency power supply to the load in the substation. At this time, in the multi-vehicle multi-pile structure 13, the current i2 of the input isolation transformer 6 and the output filter capacitor voltage u of the grid-side inverter 4 are c Sampling is performed and the sampling results are input into the multi-mechanism network control structure 14.

[0063] S22. Based on the sampling result, the instantaneous active power and the instantaneous reactive power are calculated using the instantaneous power calculation module.

[0064] Specifically, in this embodiment, the sampling result of step S21 is transformed by abc / dq to obtain the d-axis component i of i2 in the dq coordinate system. 2d and the q-axis component i 2q and u c In the dq coordinate system, the d-axis component u c_d and the q-axis component u c_q , then i 2d 、i 2q 、u c_d and u c_q The input instantaneous power calculation module performs instantaneous power calculation to obtain instantaneous active power P and instantaneous reactive power Q.

[0065] Furthermore, the instantaneous power calculation module for calculating the instantaneous power is a prior art and will not be described in detail here.

[0066] S23, inputting the instantaneous active power and the instantaneous reactive power into a network control module, and the network control module outputs voltage amplitude and angle signals to a voltage generation module.

[0067] Specifically, in this embodiment, the angle signal θ output by the network control module and the instantaneous active power P satisfy the following relationship:

[0068]

[0069] Among them, θ i is the phase angle of the voltage vector of the i-th bidirectional charging pile vehicle pile unit 2, s is the Laplace operator, P outi is the instantaneous active power corresponding to the i-th bidirectional charging pile vehicle pile unit 2, J 0i is the frequency time constant of the i-th bidirectional charging pile vehicle pile unit 2, ω0 is the rated angular frequency of the bidirectional charging pile vehicle pile unit 2, D i is the damping coefficient of the i-th bidirectional charging pile vehicle pile unit 2, i=1,2,3,...,N, and N is the total number of the bidirectional charging pile vehicle pile units 2.

[0070] The voltage amplitude U output by the network control module and the instantaneous reactive power Q satisfy the following relationship:

[0071]

[0072] Among them, U i is the voltage amplitude output by the network control module corresponding to the i-th bidirectional charging pile vehicle pile unit 2, K i is the voltage regulation coefficient of the i-th bidirectional charging pile vehicle pile unit 2, D qi is the reactive power regulation coefficient of the i-th bidirectional charging pile vehicle pile unit 2, Q outi is the instantaneous reactive power corresponding to the i-th bidirectional charging pile vehicle pile unit 2.

[0073] At this time, the output active power change of the bidirectional charging pile vehicle pile unit 2 and the rated active power change should satisfy the following relationship:

[0074]

[0075] Among them, ΔP outi is the output active power change of the i-th bidirectional charging pile vehicle pile unit 2, ΔP seti is the rated active power change of the i-th bidirectional charging pile vehicle pile unit 2, ΔP load is the load power variation in the entire multi-vehicle multi-pile structure 13, G iP and G iω They represent the active power command P of the i-th bidirectional charging pile vehicle pile unit 2 respectively. ref The transfer function of the frequency disturbance to its output power is expressed as follows:

[0076]

[0077] Among them, U0 is the output phase voltage of the multi-vehicle multi-pile structure 13, U g is the voltage amplitude at the PCC in the multi-vehicle multi-pile structure 13, X gi is the grid-side equivalent impedance of the i-th bidirectional charging pile vehicle pile unit 2.

[0078] S24, using the voltage generation module to generate a dq axis voltage control instruction, and subtracting the dq axis voltage control instruction from the dq coordinate system transformation result of the output filter capacitor voltage and inputting the result into the voltage and current inner loop.

[0079] Specifically, in this embodiment, the dq axis voltage control instructions generated by the voltage generation module include the d axis voltage control instruction u c_dref and q-axis voltage control command u c_qref The dq coordinate system transformation result of the output filter capacitor voltage includes u c_d and uc_q .

[0080] Furthermore, c_dref and u c_d Do poorly, u c_qref and u c_q Make a difference and input the result into the voltage and current inner loop.

[0081] S25, the voltage-current inner loop generates an output voltage dq coordinate axis instruction of the grid-side inverter, and then converts it into an output voltage instruction of a three-phase coordinate system through coordinate system transformation.

[0082] Specifically, in this embodiment, the output voltage dq coordinate axis instruction generated by the voltage and current inner loop is converted into an output voltage instruction of a three-phase coordinate system after dq / abc transformation.

[0083] Further, in Figure 3 In, L f and C f are the filter inductance and filter capacitance of the output filter of the grid-side inverter 4, u c That is C f Voltage across L g and R g are line inductance and resistance respectively, i1 represents the output current of the grid-side converter 4, Q ref is the reactive power command, C dc It is the DC capacitor between the two-stage cascade of the grid-side inverter 4 and the pile-side converter 3.

[0084] S26, inputting the output voltage instruction into a PWM modulation module to generate a high-frequency switching signal for the grid-side inverter.

[0085] Specifically, in this embodiment, the output voltage command obtained in S25 is input into the PWM modulation module to generate a high-frequency switching signal of the grid-side inverter 4 .

[0086] Furthermore, when the power grid 1 is out of power, the bidirectional charging pile vehicle-pile unit 2 adopts a multi-vehicle and multi-pile network control strategy to build a microgrid and mobilize any electric vehicles to connect to the bidirectional charging piles for emergency power supply to the substation, thereby eliminating the need to install emergency diesel generator sets to greatly improve the disaster prevention capabilities of the urban power supply substation, while also alleviating the pressure on emergency power supply vehicles.

[0087] In other optional embodiments, when the power grid 1 operates normally, see Figure 2 , the load switch 7 is opened, the grid-side switch 12 and the switching switch 9 are closed, the three-phase AC side of the grid-side inverter 4 is directly connected to the three-phase line of the load bus 8, and the power grid 1 directly supplies power to the substation load 10.

[0088] S3. The main control system in the charging station calculates the instantaneous power output capacity of the bidirectional charging pile vehicle pile unit according to the real-time status information of the vehicle battery obtained by the bidirectional charging pile vehicle pile unit through the vehicle pile communication system.

[0089] Specifically, in this embodiment, the real-time status information of the on-board battery includes the maximum output voltage, maximum output current, rated capacity, battery pack SOC, maximum discharge current, and battery pack temperature of the on-board battery pack of the electric vehicle. The vehicle-pile communication system and the calculation of the instantaneous power output capacity of the bidirectional charging pile vehicle-pile unit based on the real-time status information of the on-board battery are both existing technologies.

[0090] S4. Introduce an instantaneous power adjustment coefficient module into the multi-vehicle and multi-pile network control strategy, and then set the initial value of the instantaneous power adjustment coefficient of the channel where the bidirectional charging pile vehicle-pile unit is located according to the stability constraint condition.

[0091] Specifically, in this embodiment, see Figure 4 When the power grid 1 is out of power, the input of the instantaneous power adjustment coefficient module is the d-axis component i of the current i2 of the isolation transformer 6 in the synchronous rotating coordinate system. 2d and the q-axis component i 2q , the output of the voltage generation module minus the output of the instantaneous power adjustment coefficient module is used to obtain the modified dq axis voltage control command, and the modified dq axis voltage control command is input into the voltage and current inner loop after the difference between the dq coordinate system transformation result of the output filter capacitor voltage. The control equation of the instantaneous power adjustment coefficient module is shown as follows:

[0092]

[0093] in, and are respectively the d-axis component and the q-axis component in the modified dq-axis voltage control command corresponding to the i-th bidirectional charging pile vehicle pile unit 2; u c_drefi and u c_qrefi are respectively the d-axis component and the q-axis component in the dq-axis voltage control instruction generated by the voltage generation module corresponding to the i-th bidirectional charging pile vehicle pile unit 2; i 2di and i 2qi are respectively the d-axis component and the q-axis component of the current of the input isolation transformer 6 corresponding to the i-th bidirectional charging pile vehicle pile unit 2 in the synchronous rotating coordinate system; X vi is the instantaneous power adjustment coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit 2.

[0094] Further, after determining the control equation of the instantaneous power regulation coefficient module, in the steady state case where the bidirectional charging pile vehicle pile unit 2 provides emergency power supply for the station area load 10, it is necessary to set the initial value of the instantaneous power regulation coefficient to ensure the stable operation of the channel where each bidirectional charging pile vehicle pile unit 2 is located. Specifically, the initial value of the instantaneous power regulation coefficient can be set according to the stability constraint condition. The stability constraint condition of the initial value of the instantaneous power regulation coefficient is as follows:

[0095]

[0096] Among them, R i is the equivalent total output resistance of the i-th bidirectional charging pile vehicle pile unit 2, U0 is the output phase voltage of the multi-vehicle multi-pile structure 13, U g is the voltage amplitude at the PCC in the multi-vehicle multi-pile structure 13. Vi Specifically, it is the initial value of the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit 2.

[0097] S5. Based on the instantaneous power output capacity and in combination with the control law between the impact load power of each of the bidirectional charging pile vehicle pile units and the instantaneous power adjustment coefficient, dynamically adjust the instantaneous power adjustment coefficient of the channel where the bidirectional charging pile vehicle pile unit is located.

[0098] Specifically, in this embodiment, when a multi-vehicle multi-pile network control strategy is adopted to construct a microgrid to supply power to the load 10 in the substation area, the core control law between the active power setting, load power and output active power corresponding to each bidirectional charging pile vehicle pile unit 2 is as follows:

[0099]

[0100] Among them, T ij represents the control law of the power reference command of the j-th bidirectional charging pile vehicle pile unit 2 on the power output of the i-th bidirectional charging pile vehicle pile unit 2, T iL is the control law of the load power on the power output of the i-th bidirectional charging pile vehicle pile unit 2, ΔP i is the instantaneous power output capacity of the i-th bidirectional charging pile vehicle pile unit 2, ΔP refi is the output power rating of the i-th bidirectional charging pile vehicle pile unit 2, j = 1, 2, 3, ..., N. The instantaneous power output capacity of the bidirectional charging pile vehicle pile unit 2 is the instantaneous output power of the bidirectional charging pile vehicle pile unit 2. T iL Satisfies the following relationship:

[0101]

[0102] Among them, K si is a symbol for Ei is the output voltage amplitude of the i-th bidirectional charging pile vehicle pile unit 2, X vi is the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit 2, V is the grid side voltage, D pi is the active power regulation coefficient of the i-th bidirectional charging pile vehicle pile unit 2.

[0103] When i=j, T ij =T ii , at this time T ij Satisfies the following relationship:

[0104]

[0105] Among them, K sj is a symbol for E j is the output voltage amplitude of the jth bidirectional charging pile vehicle pile unit 2, D pj is the active power regulation coefficient of the j-th bidirectional charging pile vehicle pile unit 2, J 0j is the frequency time constant of the j-th bidirectional charging pile vehicle pile unit 2.

[0106] When i≠j, T ij Satisfies the following relationship:

[0107]

[0108] T iL , T ii and T ij By introducing the core control law between the active power setting, load power and output active power corresponding to each bidirectional charging pile vehicle pile unit 2, it can be further derived that during emergency power supply, the control law of the distribution of the impact load power of each bidirectional charging pile vehicle pile unit 2 and the instantaneous power adjustment coefficient of each bidirectional charging pile vehicle pile unit is as shown in the following formula:

[0109]

[0110] According to this relationship, it can be obtained that during emergency power supply, the distribution of the impact load power borne by each bidirectional charging pile vehicle pile unit 2 is inversely proportional to the instantaneous power adjustment coefficient of each bidirectional charging pile vehicle pile unit, that is, ΔP1(0)× v1 =ΔP2(0)X v2 =... =ΔP N (0)X vN .

[0111] Therefore, it can be obtained that when the emergency power supply is in progress, the instantaneous power regulation coefficient that the bidirectional charging pile unit needs to dynamically adjust when considering the change in the state of the electric vehicle battery pack is considered, and the core control law between the dynamic adjustment amount of the instantaneous power regulation coefficient and the initial value of the instantaneous power regulation coefficient is shown in the following formula:

[0112]

[0113] Where ΔX vi is the dynamic adjustment amount of the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit, is the maximum instantaneous power of the i-th bidirectional charging pile vehicle pile unit, is a symbol for According to this relationship, the instantaneous power regulation coefficient in the instantaneous power regulation coefficient module can be dynamically adjusted to optimize the instantaneous distribution of inertia support power after the load step during emergency power supply, thereby reasonably and dynamically distributing the impact load power among the bidirectional charging pile vehicle-pile units and avoiding power exceeding the limit of individual bidirectional charging pile vehicle-pile units.

[0114] It should be noted that, in some cases, the actions described in the specification can be performed in a different order and still achieve the desired results. In this embodiment, the order of steps given is only to make the embodiment appear clearer and easier to explain, rather than to limit it.

[0115] In summary, the present invention constructs a topology and control architecture that reuses bidirectional charging piles as emergency power supplies for substations, transforms bidirectional charging piles into multifunctional multiplexing equipment that provides emergency power supply, and mobilizes electric vehicles to connect to bidirectional charging piles for emergency power supply in substations when power outages occur in substations, thereby improving the disaster prevention and supply guarantee capabilities of urban power supply substations. At the same time, in the new scenario of transforming bidirectional charging piles into multifunctional multiplexing equipment that provides emergency power supply, the present invention dynamically adjusts the instantaneous power adjustment coefficient of the channel where each bidirectional charging pile vehicle pile unit is located by introducing an instantaneous power adjustment coefficient module, thereby reasonably and dynamically allocating the impact load power between each bidirectional charging pile vehicle pile unit, avoiding the power limit of individual bidirectional charging pile vehicle pile units, and ensuring the stability and safety of the bidirectional charging pile vehicle pile unit in providing emergency power supply to the substation load when the power grid is out of power.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for dynamically configuring multi-machine parameters of a multi-vehicle pile unit area emergency power supply system, characterized in that: The steps include: Construct a topology and control architecture that reuses the bidirectional charging pile vehicle pile unit as an emergency power supply for the station area; When the power grid is out of power, based on the topology and control architecture, multiple bidirectional charging pile vehicle pile units adopt a multi-vehicle multi-pile network control strategy to build a microgrid, and the load switch is closed to supply power to the load in the substation area; The main control system in the charging station calculates the instantaneous power output capacity of the bidirectional charging pile vehicle pile unit according to the real-time status information of the vehicle battery obtained by the bidirectional charging pile vehicle pile unit through the vehicle pile communication system; Introducing an instantaneous power adjustment coefficient module into the multi-vehicle multi-pile network control strategy, and then setting the initial value of the instantaneous power adjustment coefficient of the channel where the bidirectional charging pile vehicle pile unit is located according to the stability constraint condition; Based on the instantaneous power output capacity, combined with the control law between the impact load power of each of the bidirectional charging pile vehicle pile units and the instantaneous power adjustment coefficient, dynamically adjust the instantaneous power adjustment coefficient of the channel where the bidirectional charging pile vehicle pile unit is located; In the multi-vehicle multi-pile network control strategy, the core control law between the active power setting, load power and output active power corresponding to each of the bidirectional charging pile vehicle pile units is as follows: ， Among them, when i=j, ; When i≠j, ; ; and is a symbol for , ; is the output voltage amplitude of the i-th bidirectional charging pile vehicle pile unit; is the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit; V is the grid-side voltage; is the active power adjustment coefficient of the i-th bidirectional charging pile vehicle pile unit; is the output voltage amplitude of the j-th bidirectional charging pile vehicle pile unit, is the active power adjustment coefficient of the j-th bidirectional charging pile vehicle pile unit, is the frequency time constant of the j-th bidirectional charging pile vehicle pile unit; A control law representing the power output of the i-th bidirectional charging pile vehicle pile unit by the power reference instruction of the j-th bidirectional charging pile vehicle pile unit; is the control law of the load power on the power output of the i-th bidirectional charging pile vehicle pile unit; is the instantaneous power output capacity of the i-th bidirectional charging pile vehicle pile unit; is the output power rating of the i-th bidirectional charging pile vehicle pile unit; is the load power variation of all the bidirectional charging pile vehicle pile units; ; ; N is the total number of the bidirectional charging pile vehicle pile units; The control law between the impact load power and the instantaneous power adjustment coefficient of each bidirectional charging pile vehicle pile unit is as follows: ， in, is the impact load power of the unit of the i-th pile, represents the control law of the power reference instruction of the i-th bidirectional charging pile vehicle pile unit on the power output of the i-th bidirectional charging pile vehicle pile unit, s is the Laplace operator; The core control law between the dynamic adjustment amount of the instantaneous power regulation coefficient and the initial value of the instantaneous power regulation coefficient is as follows: ， in, is the dynamic adjustment amount of the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit, is the maximum instantaneous power of the i-th bidirectional charging pile vehicle pile unit, is the output phase voltage of the multi-vehicle multi-pile structure, is the voltage amplitude at the PCC in the multi-vehicle multi-pile structure, is a symbol for , is the initial value of the instantaneous power regulation coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit.

2. The method for dynamically configuring multi-machine parameters of a multi-vehicle pile unit area emergency power supply system according to claim 1 is characterized in that: The topology and control architecture for reusing the bidirectional charging pile vehicle pile unit as an emergency power supply for the station area includes the following steps: Constructing a cascade power conversion system for a bidirectional charging pile, and constructing a power supply circuit for connecting the cascade power conversion system, the power grid and the load in the station area; The power supply circuit is used to interconnect the cascade power conversion system, the power grid and the substation load to form the topology and control architecture.

3. The method for dynamic configuration of multi-machine parameters of a multi-vehicle pile unit area emergency power supply system according to claim 2 is characterized in that: The cascade power conversion system includes a grid-side inverter and a pile-side converter of each of the bidirectional charging pile vehicle pile units, and the power supply circuit includes a three-wire AC bus, an isolation transformer, a load switch, a switching switch, a four-wire AC bus, a grid-side switch and a load bus; The grid-side inverter and the pile-side converter are cascaded via a common DC bus; The three-phase AC sides of the plurality of grid-side inverters are connected in parallel and connected to one side of the triangle of the isolation transformer; The grid-side switch and the load switch are both three-phase four-wire, the two ends of the grid-side switch are respectively connected to the grid and the load bus, and the two ends of the load switch are respectively connected to the load bus and the three-phase four-wire of the star side of the isolation transformer; The switching switch is a three-phase three-wire switch, and two ends of the switching switch are respectively connected to one side of the triangle of the isolation transformer and the load bus.

4. The method for dynamically configuring multi-machine parameters of a multi-vehicle pile unit area emergency power supply system according to claim 3 is characterized in that: When the power grid is out of power, based on the topology and control architecture, multiple bidirectional charging pile vehicle pile units adopt a multi-vehicle multi-pile network control strategy to build a microgrid, and the load switch is closed to supply power to the load in the substation, including the following steps: When the power grid is out of power, sampling the current input to the isolation transformer and the output filter capacitor voltage of the grid-side inverter; Based on the sampling results, the instantaneous active power and instantaneous reactive power are calculated using the instantaneous power calculation module; The instantaneous active power and the instantaneous reactive power are input into a network control module, and the network control module outputs a voltage amplitude and an angle signal to a voltage generation module; Use the voltage generation module to generate a dq axis voltage control instruction, and input the difference between the dq axis voltage control instruction and the dq coordinate system transformation result of the output filter capacitor voltage into the voltage and current inner loop; The voltage and current inner loop generates an output voltage dq coordinate axis instruction of the grid-side inverter, and then converts it into an output voltage instruction of a three-phase coordinate system through coordinate system transformation; The output voltage instruction is input into a PWM modulation module to generate a high-frequency switching signal for the grid-side inverter.

5. The method for dynamic configuration of multi-machine parameters of a multi-vehicle pile unit area emergency power supply system according to claim 4 is characterized in that: The input of the instantaneous power adjustment coefficient module is the d-axis component and q-axis component of the current of the isolation transformer in the synchronous rotating coordinate system. The output of the voltage generation module is subtracted from the output of the instantaneous power adjustment coefficient module to obtain a modified dq-axis voltage control instruction, and the modified dq-axis voltage control instruction is subtracted from the dq coordinate system transformation result of the output filter capacitor voltage and input into the voltage and current inner loop.

6. The method for dynamically configuring multi-machine parameters of a multi-vehicle pile unit area emergency power supply system according to claim 5 is characterized in that: The modified dq axis voltage control command satisfies the following relationship: ， in, and The d-axis component and the q-axis component in the modified dq-axis voltage control instruction corresponding to the i-th bidirectional charging pile vehicle pile unit are respectively; and The d-axis component and the q-axis component in the dq-axis voltage control instruction generated by the voltage generation module corresponding to the i-th bidirectional charging pile vehicle pile unit are respectively; and The d-axis component and the q-axis component of the current input to the isolation transformer corresponding to the i-th bidirectional charging pile vehicle pile unit in the synchronous rotating coordinate system are respectively; is the instantaneous power adjustment coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit; ; N is the total number of the bidirectional charging pile vehicle pile units.

7. The method for dynamically configuring multi-machine parameters of a multi-vehicle pile unit area emergency power supply system according to claim 1 is characterized in that: The stability constraint condition of the initial value of the instantaneous power regulation coefficient satisfies the following relationship: ， in, is the equivalent total output resistance of the i-th bidirectional charging pile vehicle pile unit, is the frequency time constant of the i-th bidirectional charging pile vehicle pile unit, is the damping coefficient of the i-th bidirectional charging pile vehicle pile unit, is the rated angular frequency of the bidirectional charging pile vehicle pile unit, is the output phase voltage of the multi-vehicle multi-pile structure, is the voltage amplitude at the PCC in the multi-vehicle multi-pile structure, is the initial value of the instantaneous power adjustment coefficient corresponding to the i-th bidirectional charging pile vehicle pile unit, ; N is the total number of the bidirectional charging pile vehicle pile units.

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