A droop control method with adaptive rate of change for AC / DC hybrid microgrid

Abstract

This invention discloses an adaptive rate-of-change droop control method for AC / DC hybrid microgrids, relating to the control of interconnected converters in AC / DC hybrid microgrids. The method first normalizes the AC frequency, DC voltage, and their corresponding rates of change. Then, it constructs equations using the normalized values ​​of the actual output power of the interconnected converter, the AC frequency, the DC voltage, and their corresponding rates of change to obtain the reference power of the interconnected converter. This establishes an adaptive rule for the rate-of-change droop coefficient, and designs the rate-of-change droop coefficients for each stage based on the system's parameter characteristics. This invention can regulate the rate of change at both ends of the subgrid, balancing the normalized values ​​of the AC frequency and DC voltage rates of change, while simultaneously improving the dynamic and steady-state performance of the AC / DC subgrid.

Description

Technical Field

[0001] This invention relates to the field of converter control technology in hybrid microgrids, specifically an adaptive rate-of-change droop control method for AC / DC hybrid microgrids, which is suitable for improving the dynamic and steady-state performance of AC / DC subgrids. Background Technology

[0002] With the continuous development of new energy technologies, AC / DC hybrid microgrids have gained widespread attention due to their advantages such as independent autonomy, integration of various types of distributed generators, diverse load types, and efficient and compatible access of energy storage systems. Interconnecting converters, as bridges connecting AC / DC subgrids, handle power exchange between the two subgrids and play a crucial role in stabilizing AC / DC bus voltage and frequency, as well as improving system power quality.

[0003] Interconnected converters typically employ a dual droop control strategy, utilizing the droop characteristics of the AC / DC subgrids to achieve a normalized value equal to the AC bus frequency and DC bus voltage, thus distributing load power across the AC / DC subgrids according to their respective capacities. Droop control primarily addresses the steady-state control of DC voltage and AC frequency, lacking dynamic control over voltage and frequency. Furthermore, hybrid microgrids composed of power electronic inverters have low inertia, and droop control for micro-sources cannot provide inertia support for the AC and DC subgrids, resulting in severe instability issues with the DC subgrid bus voltage and AC subgrid bus voltage and frequency. Current research focuses on the low inertia of microgrids, particularly the instability of bus voltage and frequency in islanded grids under conditions of insufficient distributed power output and load fluctuations, addressing the problem by controlling interconnected converters to improve dynamic performance. With the widespread application of virtual synchronous motor technology, AC / DC subgrids possess a certain inertia, enabling them to support the dynamic demands of independent subgrid operation. However, when the AC and DC subgrids are interconnected, the dynamic characteristics of the subgrids will also be coupled through ILC, which will lead to a deterioration in the dynamic performance of the AC-DC hybrid microgrid. In particular, when the inertia of the two subgrids is mismatched, oscillations or even instability of DC voltage and AC frequency will occur, as well as problems such as oscillation exceeding limits, frequency change rate exceeding the limit, and voltage change rate exceeding the limit in the power transmitted by the interconnected converter. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by proposing a droop control method for adaptive rate of change in AC / DC hybrid microgrids. This method aims to achieve transient and steady-state power distribution between the two subgrids, balance the normalized values ​​of AC frequency and DC voltage, and their corresponding normalized rates of change. This improves the transient and steady-state characteristics of the AC / DC hybrid microgrid and effectively avoids power transmission oscillations and excessive voltage and frequency rate of change.

[0005] The present invention adopts the following technical solution to solve the technical problem:

[0006] The droop control method for adaptive rate of change of an AC / DC hybrid microgrid, as described in this invention, is characterized by the following steps:

[0007] 1) Establish normalized equations for AC frequency and DC voltage, and their corresponding rates of change;

[0008] 2) Normalize the sampled AC frequency and DC voltage to obtain the normalized values ​​of AC frequency, DC voltage, AC frequency change rate, and DC voltage change rate.

[0009] 3) Construct an active power reference equation using the actual output power of the interconnected converter, the sampled AC frequency and DC voltage, and the normalized value of their respective rates of change.

[0010] 4) Establish an adaptive rule for the rate of change droop coefficient of the active power reference equation;

[0011] 5) Based on the state matrix of the AC / DC hybrid microgrid, design the rate of change droop coefficient in the adaptive rule to make the AC / DC hybrid microgrid have the optimal damping ratio;

[0012] 6) Based on the power transmission limit constraints of the interconnected converter, design the maximum value of the rate of change droop coefficient in the adaptive rule.

[0013] The characteristic of the adaptive rate-of-change droop control method for AC / DC hybrid microgrids described in this invention is that, in step 1, the AC frequency and DC voltage, as well as their corresponding rate-of-change normalization equations, are established using equations (1) and (2), respectively:

[0014]

[0015]

[0016] In equations (1) and (2), ω max ω min These are the AC bus frequencies ω ac The maximum and minimum values ​​of u; max u min These are the DC bus voltages u dc The maximum and minimum values ​​of ω N u N These are the AC bus frequencies ω ac and DC bus voltage u dc The rated value, ω ac.pu u dc.pu ω ac u dc The normalized value; (dω) ac / dt) p.u 、(dudc / dt) p.u These are the rate of change of frequency dω ac / dt, voltage change rate du dc The normalization value of / dt; (dω) ac / dt) limit 、(du dc / dt) limit These are the rate of change of frequency dω ac / dt, voltage change rate du dc Maximum limit value for / dt.

[0017] In step 2, the sampled AC frequency and DC voltage are normalized using equations (3) and (4) respectively:

[0018]

[0019]

[0020] In equations (3) and (4), ω acs u dcs The AC frequency and DC voltage obtained from sampling are ω, respectively. acs.pu u dcs.pu ω acs u dcs The normalized value; dω acs / dt、du dcs / dt represents the rate of change of AC frequency and the rate of change of DC voltage obtained from sampling, respectively (dω) acs / dt) p.u 、(du dcs / dt) p.u dω acs / dt、du dcs The normalized value of / dt.

[0021] Step 3 involves using equation (5) to construct the active power reference equation:

[0022]

[0023] In equation (5), P represents the active reference power of the interconnected converter ILC. ILC k represents the actual active power output of the interconnected converter ILC. s K d These are the steady-state droop coefficient and the rate-of-change droop coefficient of the interconnected converter ILC, respectively; k ac k dc These are the equivalent droop coefficients for the AC and DC subnets, respectively.

[0024] The adaptive rule in step 4 is as follows:

[0025] When the normalized value of the rate of change and When the rate of change droop coefficient K of the interconnected converter is less than the operating margin ε, d Take steady-state value K * This enables the AC / DC hybrid microgrid to have the optimal damping ratio;

[0026] When the load disturbance on the AC / DC bus causes the rate of change to normalize... or At the instant when the motion margin ε is greater than the droop coefficient K of the rate of change d Take the maximum value K max K d Quickly adjust to the steady-state value K that gives the AC / DC hybrid microgrid the optimal damping ratio. * And the adaptive rate of change droop coefficient K is obtained using equation (6). d :

[0027]

[0028] In equation (6), ε is the action margin, and K * To ensure that the AC / DC hybrid microgrid has the optimal steady-state damping ratio, K max K is the droop coefficient of the rate of change. d The maximum value that can be obtained; t s K is the droop coefficient of the rate of change. d By K max Change to K * The trigger duration, when the normalized value of the rate of change or When t is greater than the action margin ε, s Start timing when the rate of change reaches its normal value. and When t is less than the action margin ε, s Set to 0; m is for adjusting K d The coefficient of the rate of change, making K d From K max Adjust to K * +10%*(K) max -K * The time is equal to the set transition duration Δt, and

[0029] Ensuring steady-state value K in step 5 * The value of K is chosen to achieve the optimal damping ratio for the AC / DC hybrid microgrid, i.e., K0 * The value of λ makes the eigenvalue λ in the system state matrix A, which determines the system damping ratio, satisfy equation (7):

[0030]

[0031] In equation (8), ξ is the damping ratio of the system, and λ is the eigenvalue of the state matrix A that determines the damping ratio of the system.

[0032] In step 6, based on the power transmission limit constraint of the interconnected converter, the rate of change droop coefficient K in the adaptive rule is designed using equation (9). d The maximum value K that can be obtained max :

[0033]

[0034] In equation (8), P ILC,max This represents the maximum power that the interconnected converter ILC can handle.

[0035] The present invention provides an electronic device, including a memory and a processor, wherein the memory is used to store a program that supports the processor in executing any of the aforementioned AC / DC hybrid microgrid adaptive rate-of-change droop control methods, and the processor is configured to execute the program stored in the memory.

[0036] The present invention discloses a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, performs the steps of the droop control method for the adaptive rate of change of the AC / DC hybrid microgrid.

[0037] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0038] 1. Based on steady-state power allocation, this invention introduces normalized constraints on the rate of change of AC frequency and the rate of change of DC voltage, effectively avoiding problems such as power transmission oscillation and the rate of change of DC bus voltage and AC bus frequency exceeding the limits.

[0039] 2. This invention adaptively controls the rate of change droop coefficient and rationally selects the rate of change droop coefficient at each stage, which can ensure both the dynamic characteristics of the system and the transient power distribution of the AC / DC subgrid. Attached Figure Description

[0040] Figure 1 Topology and control diagram of interconnected converter;

[0041] Figure 2 Diagram of the adaptive rate-of-change droop control structure of the invented AC / DC hybrid microgrid;

[0042] Figure 3 This is a topology diagram of an isolated HMG system on the Simulink platform.

[0043] Figure 4The diagram shows the DC bus voltage, AC bus frequency, and ILC power transfer under steady-state power distribution control only for the ILC.

[0044] Figure 5 Per-unit values ​​of DC bus voltage and AC bus frequency under steady-state power distribution control only for ILC;

[0045] Figure 6 Per-unit graph showing the DC voltage rate of change and AC frequency rate of change under adaptive rate of change droop control for AC / DC hybrid microgrids;

[0046] Figure 7 A diagram showing the per-unit values ​​of DC voltage and AC frequency, and the power transferred by the ILC under adaptive rate-of-change droop control for an AC / DC hybrid microgrid.

[0047] Figure 8 This is a per-unit diagram of the DC voltage rate of change and AC frequency rate of change under adaptive rate of change droop control for an AC / DC hybrid microgrid. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be further described in detail below with reference to the accompanying drawings:

[0049] Figure 1 The control structure of the ILC shown includes active power loop, reactive power loop and current inner loop control. Considering that there is only active power interaction between AC and DC subgrids, the reactive power reference power of the interconnected converter is taken as 0. Figure 2 Adaptive rate-of-change droop control generation of AC / DC hybrid microgrids Figure 1 The active reference power in the data.

[0050] In this embodiment, an adaptive rate-of-change droop control method for an AC / DC hybrid microgrid is proposed. This method constructs comprehensive transient and steady-state characteristic equations and combines them with an adaptive rate-of-change droop coefficient to achieve transient and steady-state power allocation between the two subgrids. The method includes the following steps:

[0051] Step 1) Establish normalized equations for AC frequency and DC voltage, and their corresponding rates of change;

[0052] In practice, the AC frequency and DC voltage, along with their corresponding normalized rate of change equations, are established using equations (1) and (2), respectively:

[0053]

[0054]

[0055] In equations (1) and (2), ω max ω minThese are the AC bus frequencies ω ac The maximum and minimum values ​​of u; max u min These are the DC bus voltages u dc The maximum and minimum values ​​of ω N u N These are the AC bus frequencies ω ac and DC bus voltage u dc The rated value, ω ac.pu u dc.pu ω ac u dc The normalized value; (dω) ac / dt) p.u 、(du dc / dt) p.u These are the rate of change of frequency dω ac / dt, voltage change rate du dc The normalization value of / dt; (dω) ac / dt) limit 、(du dc / dt) limit These are the rate of change of frequency dω ac / dt, voltage change rate du dc Maximum limit value for / dt. ω max ω min u max u min 、(dω ac / dt) limit 、(du dc / dt) limit These are fixed parameters, taken from the power grid operation control specifications.

[0056] Step 2) Normalize the sampled AC frequency and DC voltage to obtain the normalized values ​​of AC frequency, DC voltage, AC frequency change rate, and DC voltage change rate.

[0057] In step 2, the sampled AC frequency and DC voltage are normalized using equations (3) and (4) respectively:

[0058]

[0059]

[0060] In equations (3) and (4), ω acs u dcs The AC frequency and DC voltage obtained from sampling are ω, respectively. acs.pu u dcs.pu ω acs udcs The normalized value; dω acs / dt、du dcs / dt represents the rate of change of AC frequency and the rate of change of DC voltage obtained from sampling, respectively (dω) acs / dt) p.u 、(du dcs / dt) p.u dω acs / dt、du dcs The normalized value of / dt.

[0061] Step 3) Construct an active power reference equation using the actual output power of the interconnected converter, the sampled AC frequency and DC voltage, and the normalized value of their respective rates of change.

[0062] Step 3 involves using equation (5) to construct the active power reference equation:

[0063]

[0064] In equation (5), P represents the active reference power of the interconnected converter ILC. ILC k represents the actual active power output of the interconnected converter ILC. s K d These are the steady-state droop coefficient and the rate-of-change droop coefficient of the interconnected converter ILC, respectively; k ac k dc These are the equivalent droop coefficients for the AC and DC subnets, respectively.

[0065] Step 4) Establish the adaptive rule for the rate of change droop coefficient of the active power reference equation;

[0066] When operating independently of AC and DC, its busbar can be adjusted according to (dω) during the loading process at t0. ac / dt) p.u 、(du dc / dt) p.u The trend of change can be divided into two stages.

[0067] Stage I (t0-t) 0+ ): With load disturbance, |(du dc / dt) p.u |、|(dω ac / dt) p.u |Increase, t 0+ The maximum value is reached at time t. Since the maximum value of RoCoX occurs at time t... 0+ Therefore, the objective of stage I is to ensure that the proposed adaptive rate-of-change droop control scheme can effectively balance |(du)|. dc / dt) p.u | and |(dω)ac / dt) p.u The size of |. At this time, ω ac.pu u dc.pu The deviation is close to 0, and in equation (5) ω is used to balance ac.pu u dc.pu The steady-state power is relatively small, mainly due to |(du) dc / dt) p.u |、|(dω ac / dt) p.u | Bias is dominant, so the largest K can be used. d , make |(du dc / dt) p.u |、|(dω ac / dt) p.u The value is closest.

[0068] Phase II (t) 0+ -t1): t 0+ After a certain time, |(du dc / dt) p.u | and |(dω) ac / dt) p.u The value of | gradually decreases to 0, ω ac.pu u dc.pu The deviation gradually increases. At this stage, due to the maximum K... d This will reduce the stability of HMG, therefore a suitable K needs to be selected. d This is to avoid voltage and frequency oscillations, ensure that the HMG system has a good damping ratio, and avoid increasing the settling time.

[0069] Therefore, the adaptive rule for step 4 is established as follows: when the normalized value of the rate of change... and When the rate of change droop coefficient K of the interconnected converter is less than the operating margin ε, d Take steady-state value K * This ensures the AC / DC hybrid microgrid has the optimal damping ratio; when load disturbances on the AC / DC bus cause the rate of change to normalize... or At the instant when the motion margin ε is greater than the droop coefficient K of the rate of change d Take the maximum value K max K d Quickly adjust to the steady-state value K that gives the AC / DC hybrid microgrid the optimal damping ratio. * And the adaptive rate of change droop coefficient K is obtained using equation (6). d :

[0070]

[0071] In equation (6), ε is the action margin, and K* To ensure that the AC / DC hybrid microgrid has the optimal steady-state damping ratio, K max K is the droop coefficient of the rate of change. d The maximum value that can be obtained; t s K is the droop coefficient of the rate of change. d By K max Change to K * The trigger duration, when the normalized value of the rate of change When t is greater than the action margin ε, s Start timing when the rate of change reaches its normal value. and When t is less than the action margin ε, s Set to 0; m is for adjusting K d The coefficient of the rate of change, making K d From K max Adjust to K * +10%*(K) max -K * The time is equal to the set transition duration Δt, and

[0072] The small-signal state-space model of the AC / DC hybrid microgrid is established as shown in equation (7.1):

[0073]

[0074] The state variable is X = [Δω] ac ,Δu dc ,Δω ac ,Δu dcs ,ΔP ILC ] T Input variable U = [ΔP] ac_load ,ΔP dc_load ] T ;

[0075]

[0076]

[0077] Where Δ is the small semaphore of the corresponding variable, J ac J dc Let ω represent the equivalent inertia of the AC subnet and the DC subnet, respectively. α ω β ω c These are the cutoff frequencies of the equivalent filters for the AC subgrid, DC subgrid, and interconnected converters, respectively. The dynamic performance of the AC / DC hybrid microgrid can be evaluated using the eigenvalues ​​of the state matrix A.

[0078] Step 5) Based on the state matrix of the AC / DC hybrid microgrid, design the rate of change droop coefficient in the adaptive rule to make the AC / DC hybrid microgrid have the optimal damping ratio;

[0079] Ensuring steady-state value K in step 5 * The value of K is chosen to achieve the optimal damping ratio for the AC / DC hybrid microgrid, i.e., K0 * The value of λ makes the eigenvalue λ in the system state matrix A, which determines the system damping ratio, satisfy equation (7):

[0080]

[0081] In equation (7), ξ is the damping ratio of the system, and λ is the eigenvalue of the state matrix A that determines the damping ratio of the system.

[0082] Step 6) Based on the power transmission limit constraints of the interconnected converter, design the maximum value of the rate of change droop coefficient in the adaptive rule.

[0083] In step 6, based on the power transmission limit constraint of the interconnected converter, the rate of change droop coefficient K in the adaptive rule is designed using equation (8). d The maximum value K that can be obtained max :

[0084]

[0085] In equation (9), P ILC,max This represents the maximum power that the interconnected converter ILC can handle.

[0086] In this embodiment, an electronic device includes a memory and a processor. The memory stores a program that supports the processor in executing the aforementioned droop control method for adaptive rate of change of AC / DC hybrid microgrids. The processor is configured to execute the program stored in the memory.

[0087] In this embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is run by a processor, it executes the steps of the above-described droop control method for the adaptive rate of change of the AC / DC hybrid microgrid.

[0088] To verify the effectiveness of the adaptive rate-of-change droop control of the DC hybrid microgrid proposed in this invention, an islanded HMG system model was built on the Matlab / Simulink platform, and the simulation parameters are shown in Table 1.

[0089] Table 1 Simulation Parameters

[0090]

[0091] Its system topology is as follows Figure 3As shown. The DC subnetwork consists of two DC / DC converters, using virtual capacitor control; the AC subnetwork consists of two DC / AC inverters, using VSG control, and the interconnecting converter ILC uses... Figure 1 The control method shown includes an active loop, a reactive loop, and an inner current loop. The specific control method of the active loop is as follows: Figure 2 As shown, the inner current loop employs decoupling control.

[0092] To verify the effectiveness of the adaptive rate-of-change droop control for the DC hybrid microgrid proposed in this invention, two control methods were simulated for comparison: 1) The ILC uses only the traditional double-droop control method, focusing solely on steady-state power allocation. At 1 second, the AC bus is loaded with 5 kW, and the DC bus with 15 kW. 2) The ILC uses adaptive rate-of-change droop control, which, while allocating steady-state power, also constrains the AC bus frequency and DC bus voltage. At 1 second, the AC bus is loaded with 5 kW, and the DC bus with 15 kW.

[0093] like Figure 4 As shown, the ILC only uses steady-state power distribution control, with the interconnected converter transferring 5kW of power support to the DC side, ensuring that the load power borne by the two sub-networks is equal, both being 10kW. For example... Figure 4 , Figure 5 As shown, under this control mode, the AC bus frequency, DC bus voltage, and ILC transmission power oscillate, affecting the stability of the system.

[0094] Under the adaptive rate-of-change droop control of the DC subgrid submitted in this invention, such as Figure 7 , Figure 8 As shown, the interconnected converter provides 5kW of power support to the DC side, and the two sub-networks at both ends bear the same load power of 10kW, realizing the steady-state power distribution in the traditional double droop control method. Figure 7 , Figure 8 During this process, the AC bus frequency, DC bus voltage, and ILC transmission power did not oscillate, indicating that the system exhibited good dynamic characteristics. Furthermore, as... Figure 6 As shown, |(du dc / dt) p.u | and |(dω) ac / dt) p.u With the same maximum value, the dynamic characteristics of the subnets support each other, and the system has strong stability.

[0095] This invention overcomes the shortcomings of existing interconnected converter control in terms of constraints on system dynamic characteristics. It enables the system to accurately transmit power using the ILC when reaching steady state, with the AC and DC sub-networks supporting the load according to their respective capacities. Furthermore, it optimizes the dynamic processes of AC bus frequency and DC bus voltage during load surges. Simulations have verified the effectiveness of this invention.

Claims

1. A droop control method for adaptive rate of change in an AC / DC hybrid microgrid, characterized in that, Includes the following steps: 1) Establish normalized equations for AC frequency and DC voltage, and their corresponding rates of change; 2) Normalize the sampled AC frequency and DC voltage to obtain the normalized values ​​of AC frequency, DC voltage, AC frequency change rate, and DC voltage change rate. 3) Construct an active power reference equation using the actual output power of the interconnected converter, the sampled AC frequency and DC voltage, and the normalized value of their respective rates of change. 4) Establish an adaptive rule for the rate of change droop coefficient of the active power reference equation; 5) Based on the state matrix of the AC / DC hybrid microgrid, design the rate of change droop coefficient in the adaptive rule to make the AC / DC hybrid microgrid have the optimal damping ratio; 6) Based on the power transmission limit constraints of the interconnected converter, design the maximum value of the rate of change droop coefficient in the adaptive rule.

2. The droop control method for adaptive rate of change of AC / DC hybrid microgrid according to claim 1, characterized in that, In step 1, the AC frequency and DC voltage, as well as their corresponding normalized rate of change equations, are established using equations (1) and (2), respectively: (1) (2) In equations (1) and (2), ω max , ω min These are the AC bus frequencies. ω ac The maximum and minimum values; u max , u min DC bus voltage u dc The maximum and minimum values, ω N , u N These are the AC bus frequencies. ω ac and DC bus voltage u dc The rated value, ω ac.pu , u dc.pu They are respectively ω ac , u dc The normalized value; dω ac / dt ) p.u 、( du dc / dt ) p.u They are the rate of change of frequency, respectively. dω ac / dt Voltage change rate du dc / dt The normalized value; dω ac / dt ) limit 、( du dc / dt ) limit They are the rate of change of frequency, respectively. dω ac / dt Voltage change rate du dc / dt The maximum limit value.

3. The droop control method for adaptive rate of change of AC / DC hybrid microgrid according to claim 2, characterized in that, In step 2, the sampled AC frequency and DC voltage are normalized using equations (3) and (4) respectively: (3) (4) In equations (3) and (4), ω acs , u dcs These are the AC frequency and DC voltage obtained from sampling, respectively. ω acs.pu , u dcs.pu They are respectively ω acs , u dcs The normalized value; dω acs / dt , du dcs / dt These are the rates of change of AC frequency and DC voltage obtained from sampling, respectively. dω acs / dt ) p.u 、( du dcs / dt ) p.u They are respectively dω acs / dt , du dcs / dt The normalized value.

4. The droop control method for adaptive rate of change of AC / DC hybrid microgrid according to claim 3, characterized in that, Step 3 involves using equation (5) to construct the active power reference equation: (5) In equation (5), This indicates the active reference power of the interconnected converter ILC. This represents the actual active power output of the interconnected converter (ILC). k s , K d These are the steady-state droop coefficient and the rate of change droop coefficient of the interconnected converter ILC, respectively. k ac , k dc These are the equivalent droop coefficients for the AC and DC subnets, respectively.

5. The droop control method for adaptive rate of change of AC / DC hybrid microgrid according to claim 4, characterized in that, The adaptive rule in step 4 is as follows: When the normalized value of the rate of change and When the rate of change droop factor of the interconnected converter is less than the operating margin ε, K d Take steady-state value This enables the AC / DC hybrid microgrid to have the optimal damping ratio; When the load disturbance on the AC / DC bus causes the rate of change to normalize... or At the instant when the action margin ε is greater than the droop coefficient of the rate of change K d Take the maximum value K max , then K d Quickly adjust to the steady-state value that gives the AC / DC hybrid microgrid the optimal damping ratio. K * And the adaptive rate of change droop coefficient is obtained using equation (6). K d : (6) In equation (6), ε For the action margin, To ensure that the AC / DC hybrid microgrid has the optimal steady-state damping ratio, K max The droop coefficient of the rate of change K d The maximum value that can be obtained; t s The droop coefficient of the rate of change K d Depend on K max Change to The trigger duration, when the normalized value of the rate of change or When the action margin ε is greater than or equal to, t s Start timing when the rate of change reaches its normal value. and When less than the action margin ε, t s Set to 0; m To adjust K d The coefficient of the rate of change makes K d from K max Adjust to +10% ( K max - The time is equal to the set transition duration Δ. t ,and .

6. The droop control method for adaptive rate of change of AC / DC hybrid microgrid according to claim 5, characterized in that, Ensuring steady-state values ​​in step 5 K * The value of allows the AC / DC hybrid microgrid to achieve the optimal damping ratio, i.e. K * The value of makes the system state matrix A The characteristic root that determines the damping ratio of the system λ Satisfying equation (7): (7) In equation (8), ξ The damping ratio of the system, State matrix A The characteristic root that determines the damping ratio of the system is denoted by .

7. The droop control method for adaptive rate of change of AC / DC hybrid microgrid according to claim 5, characterized in that, In step 6, based on the power transmission limit constraint of the interconnected converter, the rate of change droop coefficient in the adaptive rule is designed using equation (9). K d Maximum value that can be obtained : (8) In equation (8), P ILC,max This represents the maximum power that the interconnected converter ILC can handle.

8. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store a program that supports the processor in executing the droop control method for adaptive rate of change of any of the AC-DC hybrid microgrids described in claims 1-7, and the processor is configured to execute the program stored in the memory.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run by the processor, it executes the steps of the droop control method for the adaptive rate of change of the AC / DC hybrid microgrid according to any one of claims 1-7.

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