Dual-mode self-adaptive network construction type electric vehicle charging pile control method and dual-mode self-adaptive network construction type electric vehicle charging pile control system

Abstract

The invention relates to a charging pile control technology, and provides a dual-mode self-adaptive network construction type electric vehicle charging pile control method. The method comprises the following steps: firstly, constructing a converter frequency control loop, determining whether a charging pile is in an idle mode or a V2G mode according to a change rate of a direct current side capacitor voltage, and calculating a virtual inertia coefficient J in dual modes; then, establishing a small signal model, and calculating the value of a virtual damping coefficient D in the dual mode according to the obtained virtual inertia coefficient value in the dual mode and the relationship between the virtual damping coefficient and the damping ratio; and finally, substituting a calculation numerical result into the constructed converter frequency control loop to calculate the output frequency of the converter in the dual mode. According to the invention, the supporting capability of the energy stored by the direct-current side capacitor on the power grid frequency when the charging pile is idle is fully utilized, the utilization rate of the charging pile is improved, and the grid-side frequency is stabilized.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicle charging pile control methods, and in particular to an inertia and damping design method of an electric vehicle charging pile in idle and V2G modes based on a grid-connected converter. Background Art

[0002] In response to the low inertia and weak damping problems of the power system caused by the grid connection of large-scale power electronic equipment, the development of the capacity and number of large-scale electric vehicle charging piles may cause pressure on the power grid during peak charging periods, resulting in grid frequency fluctuations and affecting the stable operation of the power system.

[0003] The control of grid-connected electric vehicle charging piles adds inertia and damping links to the control, so that the grid-connected converter has inertia and damping characteristics similar to those of a synchronous generator, effectively suppressing the fluctuation of frequency and active power, and usually adding a DC voltage synchronization link to ensure the stability of the DC side voltage. Most of the existing charging pile control technologies focus on the design and improvement of the control scheme in the electric vehicle access mode, such as the Chinese patent application with publication number CN111327041A, a DC distribution network control method regulated by a virtual inertia control strategy for electric vehicles, which discloses a DC distribution network control method regulated by a virtual inertia control strategy for electric vehicles, including establishing a mathematical model of the generator to simulate its inertia; constructing a virtual inertia control strategy for the electric vehicle charging and discharging interface converter, providing inertia for the power grid to effectively smooth the bus voltage drop caused by power fluctuations and improve the stability of the power grid. However, its control method does not take into account that when the charging pile is idle, that is, in the mode where there is no vehicle charging and discharging, the energy stored in the DC side capacitor of the charging pile is insufficiently utilized, which greatly reduces the equipment utilization rate and increases the investment cost. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to improve the utilization rate of charging piles.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] The present invention provides a dual-mode adaptive grid-type electric vehicle charging pile control method, comprising the following steps:

[0007] S1. Sample the DC side capacitor voltage and build a converter frequency control loop based on the DC voltage synchronization link, converter output power, and inertia damping link.

[0008] S2. Determine whether the charging pile is in idle mode or V2G mode according to the rate of change of the DC side capacitor voltage, and calculate the virtual inertia coefficient J in dual mode.

[0009] S3. Establish a small signal model according to the frequency control loop established in step S1, and calculate the value of the virtual damping coefficient D in the dual mode based on the relationship between the virtual inertia coefficient value, the virtual damping coefficient and the damping ratio in the dual mode obtained in step S2.

[0010] S4. According to the current operating mode of the charging pile, the virtual inertia coefficient J and the virtual damping coefficient D obtained in step S2 and step S3 are adaptively substituted into the converter frequency control loop constructed in step S1 to calculate the output frequency of the converter in the current mode.

[0011] Furthermore, the step S1 of constructing the converter frequency control loop is specifically as follows:

[0012]

[0013] In formula (1): U dc and U dc_ref are the DC capacitor voltage sampling value and reference value, K u_p and K u_i are the proportional coefficient and integral coefficient of the voltage synchronization loop PI controller, s is the Laplace operator, J is the virtual inertia coefficient, D is the virtual damping coefficient, ω n is the inverter rated frequency, P e The converter outputs electromagnetic power, and the output direction from the DC side to the AC side is positive.

[0014] The specific calculation expression for calculating the virtual inertia coefficient J in the dual mode described in step S2 is:

[0015]

[0016] In formula (2), J0 is the basic virtual inertia coefficient, k1 is the adjustment coefficient, SOC is the observed value of the battery charge coefficient of the connected vehicle, and SOC min is the minimum battery charge factor limited by the vehicle battery, U dc The DC capacitor voltage sampling value, m is the DC side capacitor voltage change rate threshold, which is used to determine the charging pile status; among them, if the change rate is less than or equal to m, the charging pile is in V2G mode.

[0017] The step S2 comprises the following steps:

[0018] S21, in the idle mode of the charging pile, calculate the value of the basic virtual inertia coefficient J0;

[0019] S22. In the V2G mode of the charging pile, calculate the value of the adjustment coefficient k1.

[0020] Furthermore, the step S21 is specifically as follows:

[0021] In the idle mode of the charging pile, the inertia power is provided by the DC side capacitor. According to the energy stored in the capacitor and the inertia required by the system under a certain frequency drop, the calculation expression of the basic virtual inertia coefficient J0 is:

[0022]

[0023] In formula (3): C dc is the DC side capacitance, ΔU dc is the peak-to-peak value of the DC side voltage, and Δω is the grid side frequency drop value.

[0024] The step S22 is specifically as follows:

[0025] In the V2G mode of the charging pile, the inertial power is provided by the battery of the electric vehicle. According to the maximum power that the electric vehicle can output, the maximum allowable power deviation and the basic inertia coefficient J0 described in step S21, the calculation expression of the adjustment coefficient k1 is obtained as follows:

[0026]

[0027] In formula (4): P max is the maximum power that an electric vehicle can output, Δω max is the maximum allowed frequency deviation value.

[0028] The specific calculation expression for calculating the value of the virtual damping coefficient D in the dual mode in step S3 is:

[0029]

[0030] In formula (5), ζ is the damping ratio and K is the synchronization coefficient.

[0031] The present invention also provides a dual-mode adaptive network-type electric vehicle charging pile control system, the system comprising:

[0032] The converter frequency control module is used to sample the DC side capacitor voltage and build a converter frequency control loop based on the DC voltage synchronization link, converter output power, and inertia damping link.

[0033] The virtual inertia coefficient calculation module is used to determine whether the charging pile is in idle mode or V2G mode according to the change rate of the DC side capacitor voltage, and calculate the virtual inertia coefficient J in the dual mode.

[0034] The virtual damping coefficient calculation module is used to establish a small signal model according to the frequency control loop established by the converter frequency control module, and calculate the value of the virtual damping coefficient D in the dual mode based on the relationship between the virtual inertia coefficient value, the virtual damping coefficient and the damping ratio in the dual mode obtained by the virtual inertia coefficient calculation module.

[0035] The data feedback module is used to input the virtual inertia coefficient J and the virtual damping coefficient D obtained by the virtual inertia coefficient calculation module and the virtual damping coefficient calculation module into the converter frequency control loop constructed by the converter frequency control module to calculate the output frequency of the converter in the current mode.

[0036] Furthermore, the specific expression of the virtual inertia coefficient in the virtual inertia coefficient calculation module is:

[0037]

[0038] In formula (2), J0 is the basic virtual inertia coefficient, k1 is the adjustment coefficient, SOC is the observed value of the battery charge coefficient of the connected vehicle, and SOC min is the minimum battery charge factor limited by the vehicle battery, U dc DC capacitor voltage sampling value, m is the DC side capacitor voltage change rate threshold, which is used to determine the status of the charging pile.

[0039] The specific expression of the virtual damping coefficient in the virtual damping coefficient calculation module is:

[0040]

[0041] In formula (5), ζ is the damping ratio and K is the synchronization coefficient.

[0042] The advantages of the present invention are:

[0043] (1) The present invention takes into account the design of the virtual inertia coefficient and the virtual damping coefficient in both the idle mode and the V2G mode of the charging pile, which can not only improve the overall utilization rate of the charging pile equipment, but also suppress the frequency and active power fluctuations of the grid connection point.

[0044] (2) When designing the virtual inertia coefficient and the virtual damping coefficient, the present invention takes into account the capacity of the DC capacitor in the idle mode of the charging pile and the influence of the SOC of the electric vehicle when the V2G mode is running, which not only improves the DC voltage stability in the idle mode of the charging pile, but also reduces the risk of the vehicle battery SOC exceeding the limit in the V2G mode of the electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the topology of an electric vehicle charging pile structure according to an embodiment of the present invention;

[0046] Figure 2 It is a schematic diagram of a dual-mode adaptive network-type electric vehicle charging pile control method according to an embodiment of the present invention;

[0047] Figure 3 The waveform diagram of the PCC point frequency and the grid-side frequency in the idle mode of the charging pile according to the embodiment of the present invention;

[0048] Figure 4This is a DC side capacitor voltage waveform diagram in the idle mode of the charging pile according to the embodiment of the present invention;

[0049] Figure 5 The waveform diagram of the converter output active power in the idle mode of the charging pile according to the embodiment of the present invention;

[0050] Figure 6 This is a waveform diagram of the PCC point frequency and the grid-side frequency in the V2G mode of an electric vehicle according to an embodiment of the present invention;

[0051] Figure 7 This is a waveform diagram of the DC side capacitor voltage in the V2G mode of an electric vehicle according to an embodiment of the present invention;

[0052] Figure 8 This is a waveform diagram of active power output by the converter in V2G mode of an electric vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Example 1

[0055] The present invention provides a dual-mode adaptive grid-type electric vehicle charging pile control method. In this embodiment, the electric vehicle charging pile topology is as follows: Figure 1 As shown, it includes electric vehicles, DC side capacitors, DC / AC converters and power grids. The DC side includes electric vehicles and DC side capacitors, electric vehicles are replaced by lithium batteries, and the power grid is equivalent to an infinite power source.

[0056] The control method used by the charging pile is as follows: Figure 2 As shown, it includes a power outer loop and a voltage and current double loop. The designed mode parameter adaptively determines the operation mode by detecting the DC side voltage change rate, and changes the virtual inertia coefficient and virtual damping coefficient according to different operation modes. Specifically, the control method includes the following steps:

[0057] S1. Sample the DC side capacitor voltage and build a converter frequency control loop based on the DC voltage synchronization link, converter output power, and inertia damping link.

[0058] The converter frequency control loop is constructed as follows:

[0059]

[0060] In formula (1): U dc and U dc_ref are the DC capacitor voltage sampling value and reference value, K u_p and K u_i are the proportional coefficient and integral coefficient of the voltage synchronization loop PI controller, s is the Laplace operator, J is the virtual inertia coefficient, D is the virtual damping coefficient, ω n is the inverter rated frequency, P e The converter outputs electromagnetic power, and the output direction from the DC side to the AC side is positive.

[0061] It can be seen from the above formula that when the virtual inertia index J and the virtual damping coefficient D are determined, the output frequency of the charging pile AC-DC converter can be obtained to realize the virtual inertia control strategy of the charging pile.

[0062] S2. Determine whether the charging pile is in idle mode or V2G mode according to the rate of change of the DC side capacitor voltage, and calculate the virtual inertia coefficient J in dual mode.

[0063] The specific calculation expression for calculating the virtual inertia coefficient J in the dual mode described in step S2 is:

[0064]

[0065] In formula (2), J0 is the basic virtual inertia coefficient, k1 is the adjustment coefficient, SOC is the observed value of the battery charge coefficient of the connected vehicle, and SOC min is the minimum battery charge factor limited by the vehicle battery, U dc The DC capacitor voltage sampling value, m is the DC side capacitor voltage change rate threshold, which is used to determine the charging pile status; among them, if the change rate is less than or equal to m, the charging pile is in V2G mode.

[0066] Furthermore,

[0067] (1) When the charging pile is in idle mode, calculate the value of the basic virtual inertia coefficient J0. At this time, the inertia power is provided by the DC side capacitor. According to the energy stored in the capacitor and the inertia required by the system under a certain frequency drop, the calculation expression of the basic virtual inertia coefficient J0 is:

[0068]

[0069] In formula (3): C dc is the DC side capacitance, ΔU dc is the peak-to-peak value of the DC side voltage, and Δω is the grid side frequency drop value.

[0070] (2) When the charging pile is in V2G mode, the value of the adjustment coefficient k1 is calculated. At this time, the inertial power is provided by the battery of the electric vehicle. According to the maximum power that the electric vehicle can output, the maximum allowable power deviation and the basic inertia coefficient J0 described in step S21, the calculation expression of the adjustment coefficient k1 is obtained as follows:

[0071]

[0072] In formula (4): P max is the maximum power that an electric vehicle can output, Δω max is the maximum allowed frequency deviation value.

[0073] S3. Establish a small signal model according to the frequency control loop established in step S1, and calculate the value of the virtual damping coefficient D in the dual mode based on the relationship between the virtual inertia coefficient value, the virtual damping coefficient and the damping ratio in the dual mode obtained in step S2.

[0074] The specific calculation expression for calculating the value of the virtual damping coefficient D in the dual mode in step S3 is:

[0075]

[0076] In formula (5), ζ is the damping ratio and K is the synchronization coefficient.

[0077] In order to verify the effectiveness of the dual-mode adaptive grid-connected electric vehicle charging pile control method provided by the present invention, a simulation model of the charging pile is built in Matlab / simulink, and the given parameters of the simulation model are shown in Table 1 below.

[0078] Table 1 Charging pile simulation model parameters

[0079]

[0080] Furthermore, in both simulation modes, the grid-side frequency step is set to -0.5 Hz at 0.3 s.

[0081] The following simulation results are obtained using the above method:

[0082] (1) When the grid-side frequency steps, the capacitor voltage change rate dU dc / dt>m, such as Figure 4 As shown, it is determined that the charging pile is in idle mode, and there is only a DC side capacitor on the DC side. The DC side capacitor will instantly provide inertia to support the PCC point frequency, such as Figure 3 As shown; when the PCC point frequency is equal to the grid side frequency, the DC side capacitor begins to slowly absorb power to the grid side to maintain the stability of the DC voltage, as shown Figure 5 As shown. The basic virtual inertia coefficient J0 is obtained by formula (6):

[0083]

[0084] The basic virtual damping coefficient D is obtained from formula (7):

[0085]

[0086] The value of adjustment coefficient k1 is obtained by formula (8):

[0087]

[0088] (2) When the grid-side frequency steps, the capacitor voltage change rate dU dc / dt≤m, such as Figure 7 As shown, it is determined that the charging pile is in V2G mode, the DC side is connected to the electric vehicle, the DC voltage remains constant, and the battery of the electric vehicle instantly provides inertia to support the PCC point frequency, such as Figure 6 As shown; when the PCC point frequency is equal to the grid side frequency, the virtual inertia coefficient and virtual damping coefficient will change adaptively according to the electric vehicle battery SOC, and the electric vehicle battery provides inertia power support to the grid side, such as Figure 8 Assume that the SOC of the electric vehicle battery is 0.3 at this time, and the virtual inertia coefficient J is obtained by formula (9):

[0089]

[0090] The virtual damping coefficient D at this time is obtained by formula (10):

[0091]

[0092] S4. According to the current operating mode of the charging pile, the virtual inertia coefficient J and the virtual damping coefficient D obtained in step S2 and step S3 are adaptively substituted into the converter frequency control loop constructed in step S1 to calculate the output frequency of the converter in the current mode.

[0093] Example 2

[0094] It should be further explained that, based on the same inventive concept, this embodiment also provides a dual-mode adaptive network-type electric vehicle charging pile control system, which executes the method of the above embodiment 1 during operation. The system includes:

[0095] The converter frequency control module is used to sample the DC side capacitor voltage and build a converter frequency control loop according to the DC voltage synchronization link, converter output power, and inertia damping link;

[0096] A virtual inertia coefficient calculation module is used to determine whether the charging pile is in idle mode or V2G mode according to the change rate of the DC side capacitor voltage, and calculate the virtual inertia coefficient J in the dual mode;

[0097] A virtual damping coefficient calculation module is used to establish a small signal model according to the frequency control loop established by the converter frequency control module, and calculate the value of the virtual damping coefficient D in the dual mode based on the relationship between the virtual inertia coefficient value, the virtual damping coefficient and the damping ratio in the dual mode obtained by the virtual inertia coefficient calculation module;

[0098] The data feedback module is used to input the virtual inertia coefficient J and the virtual damping coefficient D obtained by the virtual inertia coefficient calculation module and the virtual damping coefficient calculation module into the converter frequency control loop constructed by the converter frequency control module to calculate the output frequency of the converter in the current mode.

[0099] The construction of the converter frequency control loop described in the converter frequency control module is specifically as follows:

[0100]

[0101] In formula (1): U dc and U dc_ref are the DC capacitor voltage sampling value and reference value, K u_p and K u_i are the proportional coefficient and integral coefficient of the voltage synchronization loop PI controller, s is the Laplace operator, J is the virtual inertia coefficient, D is the virtual damping coefficient, ω n is the inverter rated frequency, P e The converter outputs electromagnetic power, and the output direction from the DC side to the AC side is positive.

[0102] The specific expression of the virtual inertia coefficient described in the virtual inertia coefficient calculation module is:

[0103]

[0104] In formula (2), J0 is the basic virtual inertia coefficient, k1 is the adjustment coefficient, SOC is the observed value of the battery charge coefficient of the connected vehicle, and SOC min is the minimum battery charge factor limited by the vehicle battery, U dc The DC capacitor voltage sampling value, m is the DC side capacitor voltage change rate threshold, which is used to determine the charging pile status; among them, if the change rate is less than or equal to m, the charging pile is in V2G mode.

[0105] The virtual inertia coefficient calculation module includes the following units:

[0106] A basic inertia coefficient calculation unit, used to calculate the value of the basic virtual inertia coefficient J0 in the idle mode of the charging pile;

[0107] The adjustment coefficient calculation unit is used to calculate the value of the adjustment coefficient k1 in the charging pile V2G mode.

[0108] The basic inertia coefficient calculation unit is specifically implemented as follows:

[0109] In the idle mode of the charging pile, the inertia power is provided by the DC side capacitor. According to the energy stored in the capacitor and the inertia required by the system under a certain frequency drop, the calculation expression of the basic virtual inertia coefficient J0 is:

[0110]

[0111] In formula (3): C dc is the DC side capacitance, U dc is the DC capacitor voltage sampling value, ΔU dc is the peak-to-peak value of the DC side voltage, Δω is the grid side frequency drop value, ω n is the rated frequency of the inverter.

[0112] The specific implementation method of the adjustment coefficient calculation unit is:

[0113] In the V2G mode of the charging pile, the inertial power is provided by the battery of the electric vehicle. According to the maximum power that the electric vehicle can output, the maximum allowable power deviation and the basic inertia coefficient J0 described in step S21, the calculation expression of the adjustment coefficient k1 is obtained as follows:

[0114]

[0115] In formula (4): P max is the maximum power that an electric vehicle can output, ω n is the inverter rated frequency, Δω max is the maximum allowed frequency deviation value.

[0116] The specific expression of the virtual damping coefficient in the virtual damping coefficient calculation module is:

[0117]

[0118] In formula (5), ζ is the damping ratio and K is the synchronization coefficient.

[0119] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-mode adaptive grid-type electric vehicle charging pile control method, characterized in that: The following steps are involved: S1, sampling the DC side capacitor voltage, and building a converter frequency control loop according to the DC voltage synchronization link, converter output power, and inertia damping link; S2. Determine whether the charging pile is in idle mode or V2G mode according to the rate of change of the DC side capacitor voltage, and calculate the virtual inertia coefficient J in the dual mode; S3, establishing a small signal model according to the frequency control loop established in step S1, and calculating the value of the virtual damping coefficient D in the dual mode according to the relationship between the virtual inertia coefficient value, the virtual damping coefficient and the damping ratio in the dual mode obtained in step S2; S4. According to the current operating mode of the charging pile, the virtual inertia coefficient J and the virtual damping coefficient D obtained in step S2 and step S3 are adaptively substituted into the converter frequency control loop constructed in step S1 to calculate the output frequency of the converter in the current mode.

2. A dual-mode adaptive grid-type electric vehicle charging pile control method according to claim 1, characterized in that: The step S1 of constructing the converter frequency control loop is specifically as follows: In formula (1): U dc and U dc_ref are the DC capacitor voltage sampling value and reference value, K u_p and K u_i are the proportional coefficient and integral coefficient of the voltage synchronization loop PI controller, s is the Laplace operator, J is the virtual inertia coefficient, D is the virtual damping coefficient, ω n is the inverter rated frequency, P e The converter outputs electromagnetic power, and the output direction from the DC side to the AC side is positive.

3. A dual-mode adaptive grid-type electric vehicle charging pile control method according to claim 1, characterized in that: The specific calculation expression for calculating the virtual inertia coefficient J in the dual mode described in step S2 is: In formula (2), J0 is the basic virtual inertia coefficient, k1 is the adjustment coefficient, SOC is the observed value of the battery charge coefficient of the connected vehicle, and SOC min is the minimum battery charge factor limited by the vehicle battery, U dc The DC capacitor voltage sampling value, m is the DC side capacitor voltage change rate threshold, which is used to determine the charging pile status; among them, if the change rate is less than or equal to m, the charging pile is in V2G mode.

4. A dual-mode adaptive grid-type electric vehicle charging pile control method according to claim 3, characterized in that: The step S2 comprises the following steps: S21, in the idle mode of the charging pile, calculate the value of the basic virtual inertia coefficient J0; S22. In the V2G mode of the charging pile, calculate the value of the adjustment coefficient k1.

5. A dual-mode adaptive grid-type electric vehicle charging pile control method according to claim 4, characterized in that: The step S21 is specifically as follows: In the idle mode of the charging pile, the inertia power is provided by the DC side capacitor. According to the energy stored in the capacitor and the inertia required by the system under a certain frequency drop, the calculation expression of the basic virtual inertia coefficient J0 is obtained as follows: In formula (3): C dc is the DC side capacitance, U dc is the DC capacitor voltage sampling value, ΔU dc is the peak-to-peak value of the DC side voltage, Δω is the grid side frequency drop value, ω n is the rated frequency of the inverter.

6. A dual-mode adaptive grid-type electric vehicle charging pile control method according to claim 4, characterized in that: The step S22 is specifically as follows: In the V2G mode of the charging pile, the inertial power is provided by the battery of the electric vehicle. According to the maximum power that the electric vehicle can output, the maximum allowable power deviation and the basic inertia coefficient J0 described in step S21, the calculation expression of the adjustment coefficient k1 is obtained as follows: In formula (4): P max is the maximum power that an electric vehicle can output, ω n is the inverter rated frequency, Δω max is the maximum allowed frequency deviation value.

7. A dual-mode adaptive grid-type electric vehicle charging pile control method according to claims 5 and 6, characterized in that: The specific calculation expression for calculating the value of the virtual damping coefficient D in the dual mode in step S3 is: In formula (5), ζ is the damping ratio and K is the synchronization coefficient.

8. A dual-mode adaptive network-type electric vehicle charging pile control system, characterized in that: The system comprises: The converter frequency control module is used to sample the DC side capacitor voltage and build a converter frequency control loop according to the DC voltage synchronization link, converter output power, and inertia damping link; A virtual inertia coefficient calculation module is used to determine whether the charging pile is in idle mode or V2G mode according to the change rate of the DC side capacitor voltage, and calculate the virtual inertia coefficient J in the dual mode; A virtual damping coefficient calculation module is used to establish a small signal model according to the frequency control loop established by the converter frequency control module, and calculate the value of the virtual damping coefficient D in the dual mode based on the relationship between the virtual inertia coefficient value, the virtual damping coefficient and the damping ratio in the dual mode obtained by the virtual inertia coefficient calculation module; The data feedback module is used to input the virtual inertia coefficient J and the virtual damping coefficient D obtained by the virtual inertia coefficient calculation module and the virtual damping coefficient calculation module into the converter frequency control loop constructed by the converter frequency control module to calculate the output frequency of the converter in the current mode.

9. A dual-mode adaptive networked electric vehicle charging pile control system according to claim 8, characterized in that: The specific expression of the virtual inertia coefficient described in the virtual inertia coefficient calculation module is: In formula (2), J0 is the basic virtual inertia coefficient, k1 is the adjustment coefficient, SOC is the observed value of the battery charge coefficient of the connected vehicle, and SOC min is the minimum battery charge factor limited by the vehicle battery, U dc DC capacitor voltage sampling value, m is the DC side capacitor voltage change rate threshold, which is used to determine the status of the charging pile.

10. A dual-mode adaptive grid-type electric vehicle charging pile control system according to claim 9, characterized in that: The specific expression of the virtual damping coefficient in the virtual damping coefficient calculation module is: In formula (5), ζ is the damping ratio, K is the synchronization coefficient, ω n is the rated frequency of the inverter.

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