Double fractional order virtual synchronous machine control method based on lead-lag correction

Abstract

The invention discloses a double fractional order virtual synchronous machine control method based on lead-lag correction, and the method comprises the steps: replacing a rotor motion equation in the double fractional order virtual synchronous machine control method with a rotor motion equation based on lead-lag correction, and adjusting the lead and lag correction parameters which are additionally introduced. The dynamic response performance of the grid-connected active power and output frequency of the double-fractional-order virtual synchronous machine under the disturbance of an active instruction, a power grid frequency and the like is improved, and the problems of dynamic oscillation and overshoot existing in the grid-connected active power and output frequency of the double-fractional-order virtual synchronous machine can be effectively solved. The method has the advantages of multiple control degrees of freedom, flexible parameter selection and capability of improving the grid-connected active dynamic response speed and reducing the output frequency adjustment time, and can be applied to the field of grid-connected control of the double fractional order virtual synchronous machine in the power electronic technology.

Description

Technical Field

[0001] The present invention relates to the field of virtual synchronous machine control technology, and in particular to a double fractional-order virtual synchronous machine control method based on lead-lag correction. The present invention is applicable to the field of double fractional-order virtual synchronous machine grid-connected control in power electronics technology and the field of microgrid incorporation of such double fractional-order virtual synchronous machine into distribution network control. Background Art

[0002] By simulating the rotor motion equations and primary voltage regulation equations of real synchronous generators, the virtual synchronous generator (VSG) can improve the grid's inertia and voltage support capabilities. However, the VSG's grid-connected active power and output frequency are prone to dynamic oscillations under disturbances such as active power commands and grid frequency. Furthermore, the fractional-order virtual synchronous generator (FOVSG) introduces a fractional-order virtual inertia control link into the VSG's rotor motion equations. By optimizing and adjusting these additional fractional-order parameters, it can effectively suppress the dynamic oscillations of the VSG's grid-connected active power and output frequency. However, the control effect in suppressing or eliminating grid-connected active power overshoot and output frequency overshoot still needs further optimization.

[0003] To this end, people have conducted various studies, such as the article entitled "Virtual Synchronous Generator Control Technology of Fractional-Order Virtual Inertia of Grid-Connected Inverter", "Control and Decision" Volume 36, Issue 02, 2021, Pages 463-468; This article proposes a fractional-order virtual synchronous machine (Fractional Order Virtual Synchronous Generator, FOVSG) control technology based on single-order fractional-order virtual inertia, which can effectively suppress the dynamic oscillation of VSG grid-connected active power and output frequency under step disturbances such as active power instructions and grid frequency, but it has the disadvantages of only adding one control degree of freedom, insufficient flexibility in parameter selection, and limited effect in suppressing VSG grid-connected active power overshoot and output frequency overshoot.

[0004] An article entitled "Active power response strategy of energy storage VSG grid-connected based on active power fractional-order differential correction" is published in "Electric Power Automation Equipment" Volume 44, Issue 02, 2024, Pages 204-210. This article proposes an improved strategy for the active power response of FOVSG grid-connected based on active power fractional-order differential correction, which can ensure that the grid-connected active power and output frequency of energy storage VSG do not exhibit dynamic oscillation when responding to active power instructions and grid frequency disturbances. However, it also has the disadvantages of limited control freedom, insufficient flexibility in parameter selection, and the ability to eliminate overshoot of active power and output frequency overshoot of energy storage VSG grid-connected, which still needs to be further strengthened.

[0005] The article entitled "Frequency stability enhancement of an islanded microgrid: Afractional-order virtual synchronous generator", LONG B, LI XY, RODRIGUEZ J, et al., "International Journal of Electrical Power and Energy Systems", 2023, 147, 108896 ("A method to enhance the frequency stability control of an islanded microgrid: fractional-order virtual synchronous generator", "International Journal of Electrical Power and Energy Systems", Vol. 147, No. 108896, 2023); This article proposes a FOVSG control strategy based on model predictive control, which can ensure that the output active power and output frequency of the VSG in the independent microgrid do not exhibit dynamic oscillation under system load disturbances. However, it has the disadvantages of only adding one degree of control freedom and insufficient flexibility in parameter selection, and does not consider the applicability of the FOVSG control strategy in the grid-connected scenario.

[0006] The article entitled “Fractional-order virtual synchronous generator”, YUY, GUAN YJ, KANG WF, et al., “IEEE Transactions on Power Electronics”, 2023, 38(6), 6874--6879 (“Fractional-order virtual synchronous machine”, IEEE Journal of Power Electronics, Vol. 38, No. 6, 2023, pp. 6874-6879); This article introduces a double fractional-order virtual inertia control method into the FOVSG grid-connected control structure, which can effectively suppress the dynamic oscillation of the VSG grid-connected active power and output frequency under step disturbances such as active power instructions and grid frequency, and increase the control freedom of the system and the flexibility of its parameter selection. However, there is a problem that the ability to suppress the overshoot of the VSG grid-connected active power and output frequency overshoot needs to be further improved.

[0007] From the above, it can be seen that although the existing technology can effectively suppress the dynamic oscillations of VSG grid-connected active power and output frequency in response to different disturbances such as active power instructions and grid frequency, it has the disadvantages of limited increase in control freedom, insufficient flexibility in parameter selection, and the control effect of suppressing VSG grid-connected active power overshoot and output frequency overshoot still needs to be further improved. Summary of the Invention

[0008] In order to overcome the limitations of the existing technical solutions given in the background technology, the present invention provides a double fractional-order virtual synchronous machine control method based on lead-lag correction to address the technical bottlenecks of insufficient dynamic oscillation suppression and large overshoot of the grid-connected active power and output frequency of the double fractional-order virtual synchronous machine. The control method can further suppress the dynamic oscillation and overshoot of the grid-connected active power and output frequency of the double fractional-order virtual synchronous machine, and has the advantages of multiple control degrees of freedom, flexible parameter selection, improved dynamic response speed of grid-connected active power and reduced output frequency adjustment time.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A double fractional-order virtual synchronous machine control method based on lead-lag correction includes the following steps:

[0011] Step 1, power calculation part, first collect the output current i of the double fractional-order virtual synchronous machine a ,i b ,i c and output voltage u a ,u b ,u c The dq components of the output current I based on the output phase angle θ of the double fractional-order virtual synchronous machine are obtained through single synchronous rotating coordinate transformation. d , I q and the dq components of the output voltage U d , U q Then, the grid-connected active power P of the double fractional-order virtual synchronous machine is obtained through the power calculation link. e and grid-connected reactive power Q e

[0012] Step 2, the primary voltage regulation part, according to the double fractional-order virtual synchronous machine grid-connected reactive power Q obtained in step 1 e and the reactive power command Q of the double fractional-order virtual synchronous machine ref , primary voltage regulation coefficient k q , and the voltage command E0, the dq axis output voltage command E of the double fractional-order virtual synchronous machine is obtained through a voltage regulation control equation. d , E q ;

[0013] Step 3: Based on the rotor motion equation with lead-lag correction, the grid-connected active power P of the double fractional-order virtual synchronous machine obtained in step 1 is calculated. e and the active power instruction P of the double fractional-order virtual synchronous machine ref , virtual inertia coefficient M, double fractional-order coefficients λ and γ, double virtual damping coefficients D1 and D2, and rated angular frequency ω0, the angular frequency deviation Δω of the double fractional-order virtual synchronous machine is obtained through the rotor motion equation based on lead-lag correction;

[0014] Step 4, output phase angle generation part, adds the double fractional-order virtual synchronous machine angular frequency deviation Δω obtained in step 3 to the rated angular frequency ω0 to obtain the output angular frequency ω of the double fractional-order virtual synchronous machine, and obtains the output phase angle θ of the double fractional-order virtual synchronous machine by performing an integral operation on the output angular frequency ω;

[0015] Step 5: First, according to the double fractional-order virtual synchronous machine output phase angle θ obtained in step 4 and the double fractional-order virtual synchronous machine dq axis output voltage command E obtained in step 2, d , E q , the three-phase voltage modulation signal E of the double fractional-order virtual synchronous machine is obtained by single synchronous rotating coordinate inverse transformation a , E b , E c , and then the three-phase voltage modulation signal E a , E b , E c The driving signal of the double fractional-order virtual synchronous machine switch tube is generated through the SVPWM modulation link.

[0016] Preferably, the grid-connected active power P in step 1 e The calculation equation used is:

[0017] P e =1.5(U d I d +U q I q ),

[0018] Grid-connected reactive power Q e The calculation equation used is:

[0019] Q e =1.5(U q I d -U d I q ).

[0020] Preferably, the output voltage instruction E in step 2 d The calculation equation used is:

[0021] E d =(Q ref -Q e )k q +E0,

[0022] Output voltage command E q The calculation equation used is:

[0023] E q =0.

[0024] Preferably, the calculation equation for the angular frequency deviation Δω in step 3 is:

[0025]

[0026] Where T1 is the leading correction parameter, T2 is the lagging correction parameter, and s is the Laplace operator.

[0027] Preferably, the calculation equation used for the output angular frequency ω in step 4 is:

[0028] ω=Δω+ω0,

[0029] The calculation equation for the output phase angle θ is:

[0030]

[0031] Where s is the Laplace operator.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention discloses a double fractional-order virtual synchronous machine control method based on lead-lag correction. The method replaces the rotor motion equation in the double fractional-order virtual synchronous machine control method with a rotor motion equation based on lead-lag correction. By adjusting the lead and lag correction parameters additionally introduced, the dynamic response performance of the grid-connected active power and output frequency of the double fractional-order virtual synchronous machine under disturbances such as active power instructions and grid frequency is improved. The method can effectively solve the dynamic oscillation and overshoot problems of the grid-connected active power and output frequency of the double fractional-order virtual synchronous machine. The method has the advantages of multiple control degrees of freedom, flexible parameter selection, and the ability to improve the dynamic response speed of the grid-connected active power and reduce the output frequency adjustment time. The method can be applicable to the field of grid-connected control of double fractional-order virtual synchronous machines in power electronics technology and the field of control of microgrids incorporating such double fractional-order virtual synchronous machines into distribution networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 4 is a control structure diagram of a double fractional-order virtual synchronous machine according to an embodiment of the present invention.

[0035] Figure 2 It is a schematic diagram of the calculation of the rotor motion equation based on lead-lag correction.

[0036] Figure 3 This is a diagram of the grid-connected active closed-loop equivalent control structure of a double fractional-order virtual synchronous machine according to an embodiment of the present invention.

[0037] Figure 4 2 is a schematic diagram of coordinate transformation and modulation according to an embodiment of the present invention.

[0038] Figure 5This is a comparative Bode diagram of a double fractional-order virtual synchronous machine before and after the invention is adopted.

[0039] Figure 6 This is a comparison diagram of simulation waveforms before and after the virtual synchronous machine adopts the present invention.

[0040] Figure 7 This is a comparison diagram of experimental waveforms of a virtual synchronous machine before and after the present invention is adopted. DETAILED DESCRIPTION

[0041] The following specific implementation will be further described in conjunction with the above drawings, specifically as follows:

[0042] See also Figure 1 The present invention proposes a double fractional-order virtual synchronous machine control method based on lead-lag correction, which includes the following steps:

[0043] Step 1, power calculation part, first collect the output current i of the double fractional-order virtual synchronous machine a ,i b ,i c and output voltage u a ,u b ,u c The dq components of the output current I based on the output phase angle θ of the double fractional-order virtual synchronous machine are obtained through single synchronous rotating coordinate transformation. d , I q and the dq components of the output voltage U d , U q Then, the grid-connected active power P of the double fractional-order virtual synchronous machine is obtained through the power calculation link. e and grid-connected reactive power Q e ;

[0044] That is, the grid-connected active power P e The calculation equation used is:

[0045] P e =1.5(U d I d +U q I q ),

[0046] Grid-connected reactive power Q e The calculation formula used is:

[0047] Qe=1.5(U q I d -U d I q ).

[0048] Step 2, the primary voltage regulation part, according to the double fractional-order virtual synchronous machine grid-connected reactive power Q obtained in step 1 eand the reactive power command Q of the double fractional-order virtual synchronous machine ref , primary voltage regulation coefficient k q , and the voltage command E0, the dq axis output voltage command E of the double fractional-order virtual synchronous machine is obtained through a voltage regulation control equation. d , E q ;

[0049] That is, the output voltage command E d The calculation equation used is:

[0050] E d =(Q ref -Q e )k q +E0,

[0051] Output voltage command E q The calculation equation used is:

[0052] E q =0.

[0053] Step 3, based on the lead-lag correction part of the rotor motion equation, such as Figure 2 As shown, according to the double fractional-order virtual synchronous machine grid-connected active power P obtained in step 1 e and the active power instruction P of the double fractional-order virtual synchronous machine ref , virtual inertia coefficient M, double fractional-order coefficients λ and γ, double virtual damping coefficients D1 and D2, and rated angular frequency ω0, the angular frequency deviation Δω of the double fractional-order virtual synchronous machine is obtained through the rotor motion equation based on lead-lag correction;

[0054] That is, the calculation equation for the angular frequency deviation Δω is:

[0055]

[0056] Where T1 is the leading correction parameter, T2 is the lagging correction parameter, and s is the Laplace operator.

[0057] Step 4, output phase angle generation part, adds the double fractional-order virtual synchronous machine angular frequency deviation Δω obtained in step 3 to the rated angular frequency ω0 to obtain the output angular frequency ω of the double fractional-order virtual synchronous machine, and obtains the output phase angle θ of the double fractional-order virtual synchronous machine by performing an integral operation on the output angular frequency ω;

[0058] That is, the calculation equation used for the output angular frequency ω is:

[0059] ω=Δω+ω0,

[0060] The calculation equation for the output phase angle θ is:

[0061]

[0062] Where s is the Laplace operator.

[0063] according to Figure 1 The grid-connected control structure given above can be combined with the above calculation equations to obtain the following Figure 3 The double fractional-order virtual synchronous machine grid-connected active closed-loop equivalent control structure diagram is shown. Figure 3 Where δ is the power factor angle of the double fractional-order virtual synchronous machine; K is the synchronous voltage coefficient of the double fractional-order virtual synchronous machine;

[0064] That is, the calculation equation used for the power factor angle δ is:

[0065]

[0066] The calculation equation for the synchronous voltage coefficient K is:

[0067]

[0068] Where U g is the grid voltage amplitude, ω g is the grid angular frequency, E is the output voltage amplitude of the double fractional-order virtual synchronous machine, X is the equivalent inductive reactance of the grid line, and s is the Laplace operator.

[0069] Step 5, such as Figure 4 As shown, first, according to the double fractional-order virtual synchronous machine output phase angle θ obtained in step 4 and the double fractional-order virtual synchronous machine dq axis output voltage command E obtained in step 2 d , E q , the three-phase voltage modulation signal E of the double fractional-order virtual synchronous machine is obtained by single synchronous rotating coordinate inverse transformation a , E b , E c , and then the three-phase voltage modulation signal E a , E b , E c The driving signal of the double fractional-order virtual synchronous machine switch tube is generated through the SVPWM modulation link.

[0070] Example

[0071] In order to verify the control effect of the double fractional-order virtual synchronous machine control method based on lead-lag correction proposed in the present invention, the double fractional-order virtual synchronous machine (hereinafter referred to as LS-FOVSG) control method based on lead-lag correction proposed in the present invention and the existing virtual synchronous machine (hereinafter referred to as VSG) control method (the VSG control method is mentioned in the background technology and is entitled “Energy Storage VSG Grid-connected Active Power Response Strategy Based on Active Fractional-order Differential Correction”, “Electric Power Automation Equipment” Vol. 44, No. 2, 2024, pp. 204-210) and the existing double fractional-order virtual synchronous machine (hereinafter referred to as FOVSG) control method {the FOVSG control method is mentioned in the background technology and is entitled “Fractional-order virtual synchronous generator”, “IEEE Transactions on Power The simulation and experimental comparison are given in the article "Fractional-order virtual synchronous machine", IEEE Journal of Power Electronics, Vol. 38, No. 6, 2023, pp. 6874-6879. The main comparison is in the response to the active power instruction P ref and grid frequency f g Grid-connected active power P under step disturbance condition e And the dynamic response performance of the output frequency f. The details are as follows:

[0072] First, relevant parameters are set. In this embodiment, the relevant parameters of the double fractional-order virtual synchronous machine control method based on lead-lag correction of the present invention are set as follows:

[0073] The rated capacity of the virtual synchronous machine is 100kVA, and the active power instruction P ref The rated angular frequency ω0 is 314.16 rad / s, and the virtual inertia coefficient M = 6ω0 = 1884.96 kg·m 2 , virtual damping coefficient D=50.66ω0=15915.35J / rad, primary voltage regulation coefficient k q 1.4×10 -4 V / var, grid voltage amplitude U g The output voltage amplitude E of the virtual synchronous machine is 311V, and the equivalent inductive reactance X of the power grid line is 0.2Ω, then the synchronous voltage coefficient K=1.5U gE / X is 725407.5. It is worth noting that if the double fractional-order coefficients λ=0, γ=1 and the double virtual damping coefficients D1=0, D2=D in FOVSG are set, then FOVSG will be equivalent to VSG, which shows that VSG is only a special case of FOVSG; if the lead correction parameter T1=0 and the lag correction parameter T2=0 in LS-FOVSG are set, then LS-FOVSG will be equivalent to FOVSG, which shows that FOVSG is only a special case of LS-FOVSG. At the same time, combined with Figure 3 After a series of formula derivation, the active power instruction P of the VSG grid-connected system can be obtained. ref To grid-connected active power P e The closed-loop transfer function is The corresponding damping ratio of the VSG grid-connected active closed-loop control system That is, the VSG grid-connected active closed-loop control system is an underdamped system, so the VSG grid-connected active power P e With the output frequency f in the active power instruction P ref and grid frequency f g Under the condition of step disturbance, dynamic oscillation will inevitably occur. Figure 3 After a series of formula derivation, the active power instruction P of the FOVSG grid-connected system can be obtained. ref To grid-connected active power P e The closed-loop transfer function is The double fractional-order coefficients in G1(s) are set to λ = 0.57, γ = 0.43, and the double virtual damping coefficients are set to D1 = 25.6ω0 = 8042.48 J / rad, D2 = D = 50.66ω0 = 15915.35 J / rad, to ensure that the FOVSG and VSG have the same grid-connected active power steady-state response performance, and can also effectively suppress the grid-connected active power P of FOVSG. e With the output frequency f in the active power instruction P ref and grid frequency f g Dynamic oscillations under step disturbances.

[0074] In this embodiment, the values of the leading correction parameter T1 and the lagging correction parameter T2 are optimized to further optimize the grid-connected active power P of the LS-FOVSG. e With the output frequency f in the active power instruction P ref and grid frequency f g Dynamic response performance under step disturbance. Similarly, according to Figure 3 After a series of formula derivation, the active power instruction P of the LS-FOVSG grid-connected system can be obtained. ref To grid-connected active power P e The closed-loop transfer function is Therefore, the closed-loop transfer functions G(s), G1(s) and G2(s) can be directly used to compare and analyze the grid-connected active power dynamic response performance of VSG, FOVSG and LS-FOVSG. In order to further simplify the theoretical analysis process, the double fractional-order coefficients in LS-FOVSG are set to λ = 0.57 and γ = 0.43, the double virtual damping coefficients are set to D1 = 25.6ω0 = 8042.48 J / rad and D2 = D = 50.66ω0 = 15915.35 J / rad, and the lead and lag correction parameters are set to T1 = 0.9 and T2 = 0.1. Substituting the above parameters into the closed-loop transfer functions G2(s), G1(s) and G(s) respectively, the active power command step disturbance ΔP of the grid-connected active power closed-loop control system of LS-FOVSG, FOVSG and VSG can be obtained. ref To the grid-connected active power response ΔP e (ΔP e / ΔP ref ) for a comparative Bode plot of Figure 5 (a). Similarly, the grid frequency step disturbance Δω of the grid-connected active closed-loop control systems of LS-FOVSG, FOVSG, and VSG can be obtained respectively: g To the grid-connected active power response ΔP e (ΔP e / Δω g ), active reference command step disturbance ΔP ref To the output angular frequency response Δω(Δω / ΔP ref ) and the grid frequency step disturbance Δω g To the output angular frequency response Δω(Δω / Δω g ) are compared with the Bode diagram, see Figure 5 (b) Figure 5 (c) with Figure 5 (d).

[0075] according to Figure 5 It can be found that there are resonance peaks before the cutoff frequency in both the grid-connected active closed-loop control system of VSG and the grid-connected active closed-loop control system of FOVSG. This phenomenon indicates that the grid-connected active power P e With the output angular frequency ω in the active power instruction P ref and grid angular frequency ω g There are problems of dynamic oscillation and overshoot under step disturbance conditions; secondly, the LS-FOVSG grid-connected active closed-loop control system proposed in the present invention does not have an obvious resonance peak before the cut-off frequency, which shows that the grid-connected active power of LS-FOVSG P e With the output angular frequency ω in the active power instruction P ref and grid angular frequency ω gThere is no dynamic oscillation problem under step disturbance conditions; III. Δω / ΔP of LS-FOVSG grid-connected active closed-loop control system ref , Δω / Δω g Compared with FOVSG, it has a smaller resonance peak, better amplitude and phase response in the medium and high frequency bands, and a wider control bandwidth. This phenomenon shows that the grid-connected active closed-loop control system corresponding to LS-FOVSG has a better control bandwidth in terms of active power instruction P. ref and grid angular frequency ω g It has faster dynamic response performance and better output frequency response performance under step disturbance conditions. It is worth noting that LS-FOVSG also has more adjustable parameters and more flexible parameter selection. For example, by selecting reasonable fractional order coefficients λ and γ, leading correction parameter T1 and lagging correction parameter T2, the grid-connected active power P of LS-FOVSG can be flexibly optimized. e The dynamic response performance of the output angular frequency ω is not listed one by one due to space limitations.

[0076] Based on the above parameter settings, simulation and experimental comparison tests were carried out, as follows:

[0077] The simulation and experimental test conditions are as follows: at the initial moment, the virtual synchronous machine stably outputs 20kW of grid-connected active power, and at 4.0s, the active power instruction P ref From 20kW to 60kW, the grid frequency f g Step down from 50Hz to 49.95Hz.

[0078] According to the above working conditions, we can obtain Figure 6 and Figure 7 The comparison diagram between simulation and experimental test is shown in the figure, where Figure 6 and Figure 7 LS-FOVSG in the figure represents a double fractional-order virtual synchronous machine control method based on lead-lag correction proposed in the present invention, FOVSG represents an existing double fractional-order virtual synchronous machine control method, that is, the curve pointed to by FOVSG is a test waveform diagram before the present invention is adopted, specifically, it is a dynamic response test waveform diagram of the existing double fractional-order virtual synchronous machine control method, VSG represents an existing virtual synchronous machine control method, that is, the curve pointed to by VSG is a test waveform diagram before the present invention is adopted, specifically, it is a dynamic response test waveform diagram of the existing virtual synchronous machine control method, and the curve pointed to by LS-FOVSG is a test waveform diagram after the present invention is adopted, specifically, it is a dynamic response test waveform diagram of the double fractional-order virtual synchronous machine control method based on lead-lag correction proposed in the present invention.

[0079] according to Figure 6 (a) It can be seen that the grid-connected active power P corresponding to the LS-FOVSG proposed in this invention ise There is no dynamic oscillation with the output frequency f, and the grid-connected active power P corresponding to the VSG is available. e There are large dynamic oscillations and power overshoots. The grid-connected active power P corresponding to the existing FOVSG e There are also dynamic oscillations and power overshoots, and the dynamic response speed is the slowest; Second, the grid-connected active power P corresponding to the LS-FOVSG proposed in this invention e The power overshoot is 1.5%, which is much smaller than the 20.8% corresponding to the existing FOVSG, and has the fastest dynamic response speed. It can be seen that the grid-connected active power P of the LS-FOVSG proposed in this invention is much higher than that of the existing VSG and FOVSG. e With the output frequency f in the active power instruction P ref The dynamic oscillation is smaller during the step from 20kW to 60kW. Compared with the existing FOVSG, LS-FOVSG has a smaller dynamic oscillation in the active power instruction P ref In the process of stepping from 20kW to 60kW, there is a smaller grid-connected active power overshoot and a faster dynamic response speed.

[0080] According to Figure 6 (b) It can be seen that, 1. The grid-connected active power P corresponding to the LS-FOVSG proposed in this invention is e There is no dynamic oscillation with the output frequency f, and the grid-connected active power P corresponding to VSG and FOVSG is available. e There are large dynamic oscillations with the output frequency f; 2. The grid-connected active power P corresponding to the LS-FOVSG proposed in this invention e Compared with the existing FOVSG, the LS-FOVSG has a smaller power overshoot and a smaller output frequency overshoot. e With the output frequency f at the grid frequency f g The dynamic oscillation is smaller during the step from 50Hz to 49.95Hz. Compared with the existing FOVSG, LS-FOVSG has a smaller dynamic oscillation at the grid frequency f g In the process of stepping from 50Hz to 49.95Hz, there is a smaller grid-connected active power overshoot and output frequency overshoot.

[0081] according to Figure 7 (a) It can be seen that the grid-connected active power P corresponding to the LS-FOVSG proposed in this invention is e There is no dynamic oscillation with the output frequency f, and the grid-connected active power P corresponding to the VSG is available. e There are large dynamic oscillations and power overshoots. The grid-connected active power P corresponding to the existing FOVSG e There are also dynamic oscillations and power overshoots, and the dynamic response speed is the slowest; Second, the grid-connected active power P corresponding to the LS-FOVSG proposed in this inventione The power overshoot is 1.6%, which is much smaller than the 23.1% corresponding to the existing FOVSG, and has the fastest dynamic response speed. It can be seen that the grid-connected active power P of the LS-FOVSG proposed in this invention is much higher than that of the existing VSG and FOVSG. e With the output frequency f in the active power instruction P ref The dynamic oscillation is smaller during the step from 20kW to 60kW. Compared with the existing FOVSG, LS-FOVSG has a smaller dynamic oscillation in the active power instruction P ref In the process of stepping from 20kW to 60kW, there is a smaller grid-connected active power overshoot and a faster dynamic response speed.

[0082] According to Figure 7 (b) It can be seen that, 1. The grid-connected active power P corresponding to the LS-FOVSG proposed in this invention is e There is no dynamic oscillation with the output frequency f, and the grid-connected active power P corresponding to VSG and FOVSG is available. e There are large dynamic oscillations with the output frequency f; 2. The grid-connected active power P corresponding to the LS-FOVSG proposed in this invention e Compared with the existing FOVSG, the LS-FOVSG has a smaller power overshoot and a smaller output frequency overshoot. e With the output frequency f at the grid frequency f g The dynamic oscillation is smaller during the step from 50Hz to 49.95Hz. Compared with the existing FOVSG, LS-FOVSG has a smaller dynamic oscillation at the grid frequency f g In the process of stepping from 50Hz to 49.95Hz, there is a smaller grid-connected active power overshoot and output frequency overshoot.

[0083] Will Figure 7 (a) and Figure 6 After comparing the results of (a), it is not difficult to see that this embodiment Figure 7 The experimental test results in (a) can be compared with Figure 6 The simulation test comparison results in (a) are kept in one-to-one correspondence, and both fully demonstrate that the LS-FOVSG proposed in the present invention can solve the grid-connected active power P of the existing VSG and FOVSG. e With the output frequency f in the active power instruction P ref Dynamic oscillation problem that is easy to occur under step disturbance; on the other hand, the LS-FOVSG proposed in this invention is better than the existing FOVSG in active power instruction P ref Under step disturbance, the LS-FOVSG has the advantages of smaller grid-connected active power overshoot and faster dynamic response speed. Therefore, compared with the existing VSG and FOVSG, the LS-FOVSG proposed in the present invention has better control effect.

[0084] And Figure 7 (b) and Figure 6 After comparing the results of (b), it is not difficult to see that this embodiment Figure 7 The experimental test results in (b) can be compared with Figure 6 The simulation test comparison results in (b) are kept in one-to-one correspondence, and both fully demonstrate that the LS-FOVSG proposed in the present invention can solve the grid-connected active power consumption of existing VSG and FOVSG. e With the output frequency f at the grid frequency f g Dynamic oscillation problem that is easy to occur under step disturbance; on the other hand, the LS-FOVSG proposed in this invention is better than the existing FOVSG in grid frequency f g Under step disturbance, the LS-FOVSG has the advantages of smaller grid-connected active power overshoot and smaller output frequency overshoot. Therefore, compared with the existing VSG and FOVSG, the LS-FOVSG proposed in the present invention has better control effect.

[0085] The above description is a detailed description of the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A double fractional-order virtual synchronous machine control method based on lead-lag correction, characterized in that: The steps include: Step 1, power calculation part, first collect the output current i of the double fractional-order virtual synchronous machine a ,i b ,i c and output voltage u a ,u b ,u c The dq components of the output current I based on the output phase angle θ of the double fractional-order virtual synchronous machine are obtained through single synchronous rotating coordinate transformation. d , I q and the dq components of the output voltage U d , U q Then, the grid-connected active power P of the double fractional-order virtual synchronous machine is obtained through the power calculation link. e and grid-connected reactive power Q e ; Step 2, the primary voltage regulation part, according to the double fractional-order virtual synchronous machine grid-connected reactive power Q obtained in step 1 e and the reactive power command Q of the double fractional-order virtual synchronous machine ref , primary voltage regulation coefficient k q , and the voltage command E0, the dq axis output voltage command E of the double fractional-order virtual synchronous machine is obtained through a voltage regulation control equation. d , E q ; Step 3: Based on the rotor motion equation with lead-lag correction, the grid-connected active power P of the double fractional-order virtual synchronous machine obtained in step 1 is calculated. e and the active power instruction P of the double fractional-order virtual synchronous machine ref , virtual inertia coefficient M, double fractional-order coefficients λ and γ, double virtual damping coefficients D1 and D2, and rated angular frequency ω0, the angular frequency deviation Δω of the double fractional-order virtual synchronous machine is obtained through the rotor motion equation based on lead-lag correction; Step 4, output phase angle generation part, adds the double fractional-order virtual synchronous machine angular frequency deviation Δω obtained in step 3 to the rated angular frequency ω0 to obtain the output angular frequency ω of the double fractional-order virtual synchronous machine, and obtains the output phase angle θ of the double fractional-order virtual synchronous machine by performing an integral operation on the output angular frequency ω; Step 5: First, according to the double fractional-order virtual synchronous machine output phase angle θ obtained in step 4 and the double fractional-order virtual synchronous machine dq axis output voltage command E obtained in step 2, d , E q , the three-phase voltage modulation signal E of the double fractional-order virtual synchronous machine is obtained by single synchronous rotating coordinate inverse transformation a , E b , E c , and then the three-phase voltage modulation signal E a , E b , E c The driving signal of the double fractional-order virtual synchronous machine switch tube is generated through the SVPWM modulation link.

2. The double fractional-order virtual synchronous machine control method based on lead-lag correction according to claim 1, characterized in that: The grid-connected active power P in step 1 e The calculation equation used is: P e =1.5(U d AND d +U q AND q ), Grid-connected reactive power Q e The calculation equation used is: Q e =1.5(U q I d -U d I q )。 3. The double fractional-order virtual synchronous machine control method based on lead-lag correction according to claim 1, characterized in that: The output voltage command E in step 2 d The calculation equation used is: E d =(Q ref -Q e )k q +E0, Output voltage command E q The calculation equation used is: E q ＝0。 4. The double fractional-order virtual synchronous machine control method based on lead-lag correction according to claim 1, characterized in that: The calculation equation for the angular frequency deviation Δω in step 3 is: Where T1 is the leading correction parameter, T2 is the lagging correction parameter, and s is the Laplace operator.

5. The double fractional-order virtual synchronous machine control method based on lead-lag correction according to claim 1, characterized in that: The calculation equation for the output angular frequency ω in step 4 is: ω=Δω+ω0, The calculation equation for the output phase angle θ is: Where s is the Laplace operator.

Images