A virtual synchronous machine optimization control method based on frequency and phase feedforward compensation

Abstract

The application discloses a virtual synchronous machine optimization control method based on frequency and phase feedforward compensation, which improves the natural oscillation angular frequency and damping ratio of a virtual synchronous machine grid-connected system, and further optimizes the dynamic response performance of the virtual synchronous machine grid-connected active power, effectively solves the dynamic oscillation and power overshoot problems of the traditional virtual synchronous machine grid-connected active power under active power instruction, grid frequency and other disturbances, has the advantages of more control degrees of freedom, more flexible control parameter selection, and faster grid-connected active power response speed, and can be applied to the field of virtual synchronous machine grid-connected control in power electronics technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of virtual synchronous machine control, in particular to a virtual synchronous machine optimization control method based on frequency and phase feedforward compensation, which is suitable for the control field of virtual synchronous machine grid connection in power electronics technology and microgrid containing such virtual synchronous machine into distribution network. BACKGROUND

[0002] The virtual synchronous machine (VSG) can provide certain voltage and virtual inertia support when it is connected to the grid, but the dynamic oscillation and power overshoot of the grid-connected active power of the VSG exist under the disturbance of active power instruction and grid frequency. In addition, although directly increasing the primary frequency coefficient of the VSG can improve the suppression ability of the dynamic oscillation and power overshoot of the grid-connected active power of the VSG, due to the mutual coupling between the primary frequency coefficient and the system damping, the grid-connected active power of the VSG has a steady-state deviation under the condition that the grid frequency deviates from the rated frequency, so simply adjusting the primary frequency coefficient of the VSG will not be able to guarantee that the grid-connected active power of the VSG has good dynamic response performance and steady-state performance at the same time.

[0003] Therefore, people have made various researches, such as the article titled "VSG Control Strategy Based on Lead-Lag Element with Feedforward Damping", High Voltage Technology, Vol. 50, No. 01, 2024, pp. 138-147; the article proposes to add an angle frequency lead-lag feedforward compensation link to the feedback channel of the grid-connected active power closed-loop equivalent control structure of the traditional virtual synchronous machine (TVSG), to improve the transient damping of the TVSG grid-connected active power closed-loop control system and suppress the dynamic oscillation and power overshoot of the grid-connected active power of the TVSG, but the lead-lag feedforward compensation link increases the order of the control system, and the high-frequency harmonic signals introduced by the differential operation also affect the operation stability of the TVSG grid-connected system.

[0004] An article titled “Optimization Strategy of Energy Storage VSG Grid-Connected Active Power Response Based on Frequency Feedforward Compensation” in Solar Energy, Vol. 45, No. 02, 2024, pp. 236-243; this article uses a grid rated angular frequency feedforward compensation link based on the traditional virtual synchronous generator (TVSG) control algorithm, enhancing the transient damping of the TVSG grid-connected system and suppressing its grid-connected active power dynamic oscillation and power overshoot. It does not require the introduction of a differential operation link and does not increase the order of the control system, but has the shortcomings of high dependence of control parameter design on system parameters, slow active power dynamic response speed, and poor applicability to grid frequency disturbances.

[0005] An article titled “A reference-feedforward-based damping method for virtual synchronous generator control” by YU Y, CHAUDHARY S K, TINAJERO G D A, et al. in IEEE Transactions on Power Electronics, 2022, 37(7), 7566-7571; this article introduces a damping control method based on active power reference feedforward into the control structure of the traditional virtual synchronous generator (TVSG), which has the advantages of keeping the system control parameters unchanged, not requiring differential operation, and eliminating dynamic oscillation of grid-connected active power under active power reference disturbance, but has the problems of slow grid-connected active power dynamic response speed, dependence of control parameter design on system parameter accuracy, and not considering the response performance optimization of grid-connected active power under grid frequency disturbance.

[0006] The article entitled "Phase feedforward damping control method for virtual synchronous generators", LI MX, YU P, HU WH, et al., "IEEE Transactions on Power Electronics", 2022, 37(8), 9790-9806 ("Phase feedforward damping control method for virtual synchronous generators", "IEEE Journal of Power Electronics", Vol. 37, No. 8, 2022, pp. 9790-9806); This article introduces a transient damping control method based on phase feedforward into the control structure of the traditional virtual synchronous generator (TVSG), which has the advantages of eliminating the dynamic oscillation of the grid-connected active power, simple control parameter design and avoidance of differential operations. However, there are problems such as the decrease slope of the open-loop gain of the control system in the high frequency band is reduced, the dynamic response performance of the grid-connected active power still needs to be further optimized, and the control freedom still needs to be further improved.

[0007] From the above, it can be seen that the existing technology can provide certain solutions and technical support for suppressing the dynamic oscillation and power overshoot problems of the grid-connected active power of the virtual synchronous machine under the disturbance of the active reference instruction and the grid frequency. However, there are still disadvantages such as harmonic interference caused by differential operation, increased control system order, difficulty in control parameter design, slow dynamic response speed of the grid-connected active power, and the need to further improve the control freedom. Summary of the Invention

[0008] In order to overcome the limitations of the various technical solutions given in the background technology, the present invention provides a virtual synchronous machine optimization control method based on frequency and phase feedforward compensation for the dynamic oscillation and power overshoot problems of the traditional virtual synchronous machine's grid-connected active power under disturbances such as active power instructions and grid frequency. This control method can effectively solve the dynamic oscillation and power overshoot problems of the virtual synchronous machine's grid-connected active power under disturbances such as active power instructions and grid frequency without changing the steady-state error of the grid-connected active power and the control system order, and can also improve its grid-connected active power response speed. It has the advantages of keeping the system control order unchanged, avoiding differential operations, simple parameter design and more control freedom.

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

[0010] A virtual synchronous machine optimization control method based on frequency and phase feedforward compensation includes the following steps:

[0011] Step 1, power calculation part, first collect the grid-connected current i of the virtual synchronous machine a , i b , i c and output voltage u a , u b , u c , through single synchronous rotating coordinate transformation to obtain the dq component I d , I q of the grid-connected current and the dq component U d , U q of the output voltage based on the phase angle θ of the virtual synchronous machine output, and then through the power calculation equation to obtain the grid-connected active power P e and the grid-connected reactive power Q e of the virtual synchronous machine;

[0012] Step 2, primary voltage regulation part, according to the grid-connected reactive power Q e of the virtual synchronous machine obtained in step 1 and the reactive reference instruction Q ref of the virtual synchronous machine, the primary voltage regulation coefficient k q , and the voltage reference instruction E0 of the virtual synchronous machine, through the primary voltage regulation equation to obtain the dq axis output voltage reference instruction E d , E q of the virtual synchronous machine;

[0013] Step 3, rotor motion equation part, according to the grid-connected active power P e of the virtual synchronous machine obtained in step 1 and the virtual inertia coefficient J, the primary frequency modulation coefficient k p , the active reference instruction P ref , the angular frequency feedforward compensation coefficient b, and the rated angular frequency ω0 of the power grid, through the rotor motion equation to obtain the angular frequency deviation Δω;

[0014] Step 4, frequency feedforward compensation part, subtract the grid-connected active power P e of the virtual synchronous machine obtained in step 1 from the active reference instruction P ref to obtain the grid-connected active power deviation ΔP e , and then through the frequency feedforward compensation link containing the virtual inertia coefficient J, the primary frequency modulation coefficient k p , the rated angular frequency ω0 of the power grid, and the angular frequency feedforward compensation coefficient b to obtain the output angular frequency compensation amount Δω b of the virtual synchronous machine b , add the output angular frequency compensation amount Δω b to the angular frequency deviation Δω obtained in step 3 and the rated angular frequency ω0 of the power grid to obtain the output angular frequency ω of the virtual synchronous machine;

[0015] Step 5, phase feedforward compensation part, according to the grid-connected active power deviation ΔP eAfter the phase feedforward compensation link containing the virtual inertia coefficient J, the first-order frequency modulation coefficient k p , the rated angular frequency of the power grid ω0and the phase feedforward compensation coefficient a, the output phase angle compensation amount Δθ of the virtual synchronous machine is obtained a ;

[0016] Step 6, the output phase angle generation part, the output angular frequency ω of the virtual synchronous machine obtained in step 4 is added to the output phase angle compensation amount Δθ of the virtual synchronous machine obtained in step 5 after an integral operation link a The output phase angle θ of the virtual synchronous machine is obtained.

[0017] Step 7, according to the output phase angle θ of the virtual synchronous machine obtained in step 6, and the virtual synchronous machine dq-axis output voltage reference instruction E d , E q , the three-phase bridge arm voltage modulation signal E a , E b , E c is obtained by single synchronous rotating coordinate inverse transformation a , E b , E c After the SVPWM modulation link, the drive signal of the virtual synchronous machine inverter bridge switching tube is generated.

[0018] Preferably, the grid-connected active power P e The calculation formula used is:

[0019] P c =1.5(U d I d +U q I q ),

[0020] The calculation formula used for the grid-connected reactive power Q e is:

[0021] Q c =1.5(U q I d -U d I q )。

[0022] Preferably, the calculation formula used for the output voltage reference instruction E d in step 2 is:

[0023] E d =E0+(Q ref -Q c )k q , the calculation formula used for the output voltage reference instruction E q is:

[0024] E q = 0.

[0025] Preferably, the calculation formula of the angular frequency deviation Δω in step 3 is:

[0026]

[0027] In the formula, s is the Laplace operator.

[0028] Preferably, the calculation formula of the grid-connected active power deviation ΔP e in step 4 is:

[0029] ΔP c = P ref - P c ,

[0030] The calculation formula of the output angular frequency compensation amount Δω b in step 5 is:

[0031]

[0032] The calculation formula of the virtual synchronous machine output angular frequency ω is:

[0033] ω = Δω b + Δω + ω0,

[0034] In the formula, s is the Laplace operator.

[0035] Preferably, the calculation formula of the output phase angle compensation amount Δθ a in step 6 is:

[0036]

[0037] In the formula, s is the Laplace operator.

[0038] Preferably, the calculation formula of the virtual synchronous machine output phase angle θ is:

[0039]

[0040] In the formula, s is the Laplace operator.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] The present invention discloses a virtual synchronous machine optimization control method based on frequency and phase feedforward compensation. This control method improves the natural oscillation angular frequency and damping ratio of the virtual synchronous machine grid-connected system by simultaneously introducing angular frequency feedforward and phase feedforward compensation links without changing the steady-state error of the grid-connected active power and the control system order. This method further optimizes the dynamic response performance of the virtual synchronous machine grid-connected active power, effectively solving the dynamic oscillation and power overshoot problems of the traditional virtual synchronous machine grid-connected active power under disturbances such as active power instructions and grid frequency. This method has the advantages of more control degrees of freedom, more flexible control parameter selection, and faster response speed to the grid-connected active power. This method is applicable to the virtual synchronous machine grid-connected in power electronics technology and the integration of microgrids containing such virtual synchronous machines into distribution network control. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 4 is a diagram of a virtual synchronous machine control structure according to an embodiment of the present invention.

[0044] Figure 2 It is a calculation diagram of the output angular frequency compensation amount and the output phase angle compensation amount.

[0045] Figure 3 This is a diagram of a closed-loop equivalent control structure of a virtual synchronous machine grid-connected active power according to an embodiment of the present invention.

[0046] Figure 4 2 is a schematic diagram of coordinate transformation and modulation according to an embodiment of the present invention.

[0047] Figure 5 This is a comparison diagram of simulation waveforms before and after the virtual synchronous machine adopts the present invention.

[0048] Figure 6 This is a comparison diagram of experimental waveforms of a virtual synchronous machine before and after the present invention is adopted. DETAILED DESCRIPTION

[0049] The following specific implementation will be further described in conjunction with the above drawings, specifically as follows:

[0050] See also Figure 1 The present invention proposes a virtual synchronous machine optimization control method based on frequency and phase feedforward compensation, comprising the following steps:

[0051] Step 1, power calculation part, first collect the grid-connected current i of the virtual synchronous machine a ,i b ,i c and output voltage u a ,u b ,u c The dq component of the grid-connected current I based on the virtual synchronous machine output phase angle θ is obtained through single synchronous rotating coordinate transformation. d , Iq and the dq components of the output voltage U d , U q , the active power P e and the reactive power Q e of the virtual synchronous machine are obtained through the power calculation equation

[0052] wherein the active power P e is calculated by the formula:

[0053] P c = 1.5 (U d I d + U q I q ),

[0054] and the reactive power Q e is calculated by the formula:

[0055] Q c = 1.5 (U q I d - U d I q ).

[0056] Step 2, the primary voltage regulating part, according to the virtual synchronous machine active power P e and the virtual synchronous machine reactive power reference Q ref , the primary voltage regulating coefficient k p , the virtual synchronous machine voltage reference E0, the dq axis output voltage reference E d of the virtual synchronous machine is obtained through the primary voltage regulating equation q

[0057] wherein the output voltage reference E d is calculated by the formula:

[0058] E d = E0 + (Q ref - Q c ) k q ,

[0059] and the output voltage reference E q is calculated by the formula:

[0060] E q = 0.

[0061] Step 3, the rotor motion equation part, according to the virtual synchronous machine active power P e and the virtual inertia coefficient J, the primary frequency regulating coefficient k p , the active power reference P ref ​, the angular frequency feedforward compensation coefficient b, and the grid rated angular frequency ω0, the angular frequency deviation Δω is obtained through the rotor motion equation;

[0062] The calculation formula of the angular frequency deviation Δω is:

[0063]

[0064] In the formula, s is the Laplace operator.

[0065] Step 4, the frequency feedforward compensation part, as shown in Figure 2 (a), the active reference instruction P ref Subtract the virtual synchronous machine grid-connected active power P e Get the grid-connected active power deviation ΔP e After that, through the frequency feedforward compensation link containing the virtual inertia coefficient J, the primary frequency modulation coefficient k p , the grid rated angular frequency ω0 and the angular frequency feedforward compensation coefficient b, the output angular frequency compensation amount Δω of the virtual synchronous machine is obtained b , the output angular frequency compensation amount Δω b Add the angular frequency deviation Δω obtained in step 3 and the grid rated angular frequency ω0 to obtain the output angular frequency ω of the virtual synchronous machine.

[0066] The calculation formula of the grid-connected active power deviation ΔPe is:

[0067] ΔP c = P ref -P c ,

[0068] The calculation formula of the output angular frequency compensation amount Δω b is:

[0069]

[0070] The calculation formula of the virtual synchronous machine output angular frequency ω is:

[0071] ω = Δω b + Δω + ω0,

[0072] In the formula, s is the Laplace operator.

[0073] Step 5, the phase feedforward compensation part, as shown in Figure 2 (b), the virtual synchronous machine grid-connected active power deviation ΔP c obtained in step 4 is passed through the phase feedforward compensation link containing the virtual inertia coefficient J, the primary frequency modulation coefficient k p , the grid rated angular frequency ω0 and the phase feedforward compensation coefficient a, to obtain the output phase angle compensation amount Δθ of the virtual synchronous machine a;

[0074] wherein the output phase angle compensation amount Δθ a The calculation formula used is:

[0075]

[0076] wherein s is the Laplace operator.

[0077] Step 6, the output phase angle generating part, adds the output phase angle compensation amount Δθ a obtained in step 5 to the virtual synchronous machine output angular frequency ω obtained in step 4 after an integral operation link

[0078] The calculation formula used for the virtual synchronous machine output phase angle θ is:

[0079]

[0080] wherein s is the Laplace operator.

[0081] In combination with Figure 1 the power transmission model and according to the above control, the grid-connected active power closed-loop equivalent control structure diagram of the virtual synchronous machine can be obtained as shown in Figure 3 . Figure 3 wherein δ is the power factor angle of the virtual synchronous machine; and K is the synchronous voltage coefficient of the virtual synchronous machine;

[0082] The calculation formula used for the power factor angle δ of the virtual synchronous machine is:

[0083]

[0084] The calculation formula used for the synchronous voltage coefficient K of the virtual synchronous machine is:

[0085]

[0086] wherein ω g is the grid angular frequency, U g is the grid voltage amplitude, E is the output voltage amplitude of the virtual synchronous machine, X is the equivalent inductance of the line, and s is the Laplace operator.

[0087] Step 7, as shown in Figure 4 , first, the virtual synchronous machine output phase angle θ obtained in step 6 and the virtual synchronous machine dq-axis output voltage reference instruction E d , E q obtained in step 2 are subjected to single synchronous rotation coordinate inverse transformation to obtain three-phase bridge arm voltage modulation signals E a , E b , E c , and then the three-phase bridge arm voltage modulation signals Ea , E b , E c The driving signal of the virtual synchronous machine inverter bridge switch tube is generated through the SVPWM modulation link.

[0088] Example

[0089] In order to verify the control effect of the virtual synchronous machine optimization control method based on frequency and phase feedforward compensation proposed in the present invention, the virtual synchronous machine (hereinafter referred to as FPFCVSG) control method with an additional angular frequency feedforward compensation link and a phase feedforward compensation link proposed in the present invention and the existing traditional virtual synchronous machine (hereinafter referred to as TVSG) control method (the TVSG control method is mentioned in the background technology and is given in the article entitled "Optimization Strategy of Active Response of Energy Storage VSG Grid-connected Based on Frequency Feedforward Compensation", "Acta Energiae Solaris Sinica", Vol. 45, No. 02, pp. 236-243) are simulated and experimentally compared under two conditions of whether the proposed frequency and phase feedforward compensation are introduced. The main comparison is in response to the active power reference instruction P ref and grid frequency f g Grid-connected active power P under step disturbance conditions e And the response performance of the output frequency f. The details are as follows:

[0090] First, set the relevant parameters. In this embodiment, the relevant parameters in the FPFCVSG optimization control method of the present invention are set as follows:

[0091] The rated capacity of the virtual synchronous machine is 100kVA, and the active power reference instruction P ref The power grid is 20kW, the rated angular frequency ω0 is 314.16rad / s, and the virtual inertia coefficient J is 6kg·m 2 , the primary frequency modulation coefficient k p is 15915.5J / rad, the grid voltage amplitude U g is 311V, primary voltage regulation coefficient k q 1.4×10 -4 V / var, the virtual synchronous machine output voltage amplitude E is 311V, the line equivalent inductive reactance X is 0.1Ω, then the synchronous voltage coefficient K=1.5UgE / X is 1450815. Figure 3 And after the formula derivation process, TVSG(k p =15915.5J / rad) Damping ratio of the grid-connected active power closed-loop control system is 0.15 less than 1, that is, the system is underdamped, and its natural oscillation angular frequency It has a smaller value of 27.74rad / s, so TVSG(k p =15915.5J / rad) of the grid-connected active power Pe In the active reference instruction P ref and grid frequency f g Under disturbance, there will inevitably be problems such as dynamic oscillation, power overshoot and slow dynamic response speed; TVSG (k p =145377.4J / rad) Damping ratio of the grid-connected active power closed-loop control system is 1.39 greater than 1, that is, the system is an overdamped system, and its natural oscillation angular frequency It has a smaller value of 27.74rad / s, so TVSG(k p =145377.4J / rad) of the grid-connected active power P e In the active power reference command P ref and grid frequency f g Under step disturbance conditions, there will be no state oscillation and power overshoot problems, but there will still be the problem of slow dynamic response speed.

[0092] In this embodiment, the FPFCVSG grid-connected active power closed-loop control system is set as an over-damping system to ensure that the grid-connected active power P of the virtual synchronous machine is e In the active power reference command P ref and grid frequency f g Under step disturbance conditions, the effect of no dynamic oscillation and no power overshoot is achieved. At the same time, combined with Figure 3 And through the formula derivation process, the damping ratio of the FPFCVSG grid-connected active power closed-loop control system is obtained and its natural oscillation angular frequency Here a is set to 0.12 and b is set to 1, then ξ2=1.39=ξ1>ξ, ω n2 =39.23rad / s>ω n =ω n1 , so the grid-connected active power P of FPFCVSG e In the active power reference command P ref and grid frequency f g Under step disturbance conditions, there will be no dynamic oscillation and power overshoot, and it will have a faster dynamic response speed than TVSG.

[0093] Based on the above parameter settings, simulation and experimental comparison tests were carried out, as follows:

[0094] 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 the grid frequency is f g Keep 50Hz unchanged, active reference instruction P at 4.0s refFrom 20kW step to 60kW; initial moment virtual synchronous machine stable output 20kW grid-connected active power, grid frequency f g Keep 50Hz unchanged, at 4.0s grid frequency f g From 50Hz step to 49.95Hz.

[0095] According to the above working conditions, respectively get as Figure 5 And Figure 6 The simulation and experimental test comparison chart is shown, wherein, Figure 5 And Figure 6 The FPFCVSG in and TVSG represent a kind of virtual synchronous machine optimization control method based on frequency and phase feedforward compensation provided in the application, and the existing traditional virtual synchronous machine control method, that is, TVSG (k p The curve pointed to by TVSG (k p The curve pointed to by TVSG (k p The curve pointed to by TVSG (k p The curve pointed to by FPFCVSG is the test waveform after using the application, specifically the test waveform of the virtual synchronous machine optimization control method based on frequency and phase feedforward compensation provided in the application.

[0096] According to Figure 5 (a) can be seen, first, the grid-connected active power corresponding to the FPFCVSG of the application has no dynamic oscillation and power overshoot and the fastest dynamic response speed, the grid-connected active power corresponding to the existing TVSG (k p =15915.5J / rad) has a large dynamic oscillation and power overshoot; second, the grid-connected active power regulation time of the FPFCVSG provided in the application is 0.08s, which is much smaller than 1.38s corresponding to the existing TVSG (k p =15915.5J / rad) and 0.51s corresponding to TVSG (k p =145377.4J / rad); third, the overshoot amplitude of the virtual synchronous machine output frequency f corresponding to the FPFCVSG provided in the application is 0.05Hz, which is lower than 0.11Hz corresponding to the existing TVSG (k p =15915.5J / rad). It can be seen that the grid-connected active power of the FPFCVSG provided in the application is compared with the existing TVSG, and the grid-connected active power reference instruction P refThe step from 20kW to 60kW has smaller power overshoot and faster response speed.

[0097] According to Figure 5 (b) It can be seen that the grid-connected active power corresponding to the FPFCVSG proposed in the present invention has neither dynamic oscillation nor power overshoot. p =15915.5J / rad) the grid active power corresponding to the large dynamic oscillation and power overshoot, and TVSG (k p =145377.4J / rad) The corresponding grid-connected active power has no dynamic oscillation and no power overshoot, but k p The increase of P e There is an error of 40.66kW; Second, the grid-connected active power adjustment time corresponding to the FPFCVSG proposed in the present invention is 0.08s, which is much shorter than the existing TVSG (k p =1591 5.5J / rad) corresponds to 1.41s and TVSG(k p =145377.4J / rad) corresponding to 0.55s; It can be seen that the grid-connected active power of the FPFCVSG proposed in the present invention is greater than that of the existing TVSG at the grid frequency f g The process of stepping from 50Hz to 49.95Hz has smaller power overshoot and faster response speed, and does not change the steady-state error of grid-connected active power.

[0098] according to Figure 6 (a) It can be concluded that, first, the grid-connected active power corresponding to the FPFCVSG proposed in the present invention has neither dynamic oscillation nor power overshoot and has the fastest dynamic response speed. The existing TVSG (k p =15915.5J / rad) has large dynamic oscillation and power overshoot in the grid-connected active power; Second, the grid-connected active power adjustment time corresponding to the FPFCVSG proposed in the present invention is 0.15s, which is much shorter than the existing TVSG (k p =15915.5J / rad) corresponds to 1.65s and TVSG(k p =145377.4J / rad) corresponds to 0.72s; Third, the overshoot amplitude of the virtual synchronous machine output frequency f corresponding to the FPFCVSG proposed in the present invention is 0.07Hz, which is lower than that of the existing TVSG (k p =15915.5J / rad) corresponds to 0.15Hz. Therefore, from Figure 6 In (a), we can see that the grid-connected active power of the FPFCVSG proposed in this invention is higher than that of the existing TVSG in terms of the active power reference instruction P. ref The step from 20kW to 60kW has smaller power overshoot and faster response speed.

[0099] According to the present application Figure 6 (b) can be seen, first, the corresponding grid-connected active power of the FPFCVSG of the present application has neither dynamic oscillation nor power overshoot, and the corresponding grid-connected active power of the TVSG(k p = 15915.5 J / rad) has great dynamic oscillation and power overshoot, and the corresponding grid-connected active power of the TVSG(k p = 145377.4 J / rad) has neither dynamic oscillation nor power overshoot, but the increase of k p makes the P e has an error of 41.02 kW; second, the regulation time of the corresponding grid-connected active power of the FPFCVSG of the present application is 0.13 s, which is far less than the 1.69 s of the TVSG(k p = 15915.5 J / rad) and the 0.63 s of the TVSG(k p = 145377.4 J / rad); thus, it can be seen that, compared with the TVSG, the corresponding grid-connected active power of the FPFCVSG of the present application has smaller power overshoot and faster response speed in the process from 50 Hz step to 49.95 Hz, and does not change the steady-state error of the grid-connected active power. g

[0100] The results of Figure 6 (a) and Figure 5 (a) are compared, and it is not difficult to see that the experimental test comparison results in the present embodiment Figure 6 (a) can be one-to-one corresponding with the simulation test comparison results in Figure 5 (a), and both sufficiently show that the FPFCVSG of the present application has faster grid-connected active power response speed and smaller active power overshoot under the active power reference instruction P ref step disturbance than the TVSG, and thus, the control effect of the FPFCVSG of the present application is better than that of the TVSG.

[0101] The results of Figure 6 (b) and Figure 5 (b) are compared, and it is not difficult to see that the experimental test comparison results in the present embodiment Figure 6 (b) can be one-to-one corresponding with the simulation test comparison results in Figure 5 (b), and both sufficiently show that the FPFCVSG of the present application has faster grid-connected active power response speed and smaller active power overshoot under the grid frequency f g step disturbance and does not change the steady-state error of the grid-connected active power than the TVSG, and thus, the control effect of the FPFCVSG of the present application is better than that of the TVSG.​

[0102] The above description is for the preferred embodiment of the present application, but the embodiment is not intended to limit the scope of the patent application of the present application. Any equivalent changes or modifications made under the technical spirit of the present application should be covered by the patent scope of the present application.

Claims

1. A virtual synchronous machine optimization control method based on frequency and phase feedforward compensation, characterized in that: The steps include: Step 1, power calculation part, first collect the grid-connected current i of the virtual synchronous machine a ,i b ,i c and output voltage u a ,u b ,u c The dq component of the grid-connected current I based on the virtual synchronous machine output phase angle θ is obtained through single synchronous rotating coordinate transformation. d , I q and the dq components of the output voltage U d , U q , and then the grid-connected active power P of the virtual synchronous machine is obtained through the power calculation equation e and grid-connected reactive power Q e ; Step 2, primary voltage regulation part, according to the virtual synchronous machine grid-connected reactive power Q obtained in step 1 e and the reactive power reference instruction Q of the virtual synchronous machine ref , primary voltage regulation coefficient k q , the voltage reference instruction E0 of the virtual synchronous machine, and the dq axis output voltage reference instruction E of the virtual synchronous machine are obtained through a voltage regulation equation. d , E q ; Step 3, rotor motion equation part, according to the virtual synchronous machine grid-connected active power P obtained in step 1 e And virtual inertia coefficient J, primary frequency modulation coefficient k p , Active reference instruction P ref , angular frequency feedforward compensation coefficient b, and the grid rated angular frequency ω0, the angular frequency deviation Δω is obtained through the rotor motion equation; Step 4, frequency feedforward compensation part, the active reference instruction P ref Subtract the virtual synchronous machine grid-connected active power P obtained in step 1 e Get the grid-connected active power deviation ΔP e After that, it contains virtual inertia coefficient J, primary frequency modulation coefficient k p The output angular frequency compensation value Δω of the virtual synchronous machine is obtained by the frequency feedforward compensation link of the grid rated angular frequency ω0 and the angular frequency feedforward compensation coefficient b. b , the output angular frequency compensation Δω b Add the angular frequency deviation Δω obtained in step 3 and the rated angular frequency ω0 of the power grid to obtain the output angular frequency ω of the virtual synchronous machine; Step 5, phase feedforward compensation part, will be based on the virtual synchronous machine grid active power deviation ΔP obtained in step 4 e After including the virtual inertia coefficient J, the primary frequency modulation coefficient k p The output phase angle compensation value Δθ of the virtual synchronous machine is obtained by the phase feedforward compensation link of the grid rated angular frequency ω0 and the phase feedforward compensation coefficient a. a ; Step 6, the output phase angle generation part, adds the virtual synchronous machine output angular frequency ω obtained in step 4 to the virtual synchronous machine output phase angle compensation Δθ obtained in step 5 after the integral operation link a Get the output phase angle θ of the virtual synchronous machine; Step 7: First, according to the virtual synchronous machine output phase angle θ obtained in step 6 and the virtual synchronous machine dq axis output voltage reference instruction E obtained in step 2, d , E q , the three-phase bridge arm voltage modulation signal E is obtained by single synchronous rotating coordinate inverse transformation a , E b , E c , and then the three-phase bridge arm voltage modulation signal E a , E b , E c The driving signal of the virtual synchronous machine inverter bridge switch tube is generated through the SVPWM modulation link.

2. The virtual synchronous machine optimization control method based on frequency and phase feedforward compensation according to claim 1 is characterized in that: The grid-connected active power P in step 1 e The calculation formula used is: P c =1.5(U d AND d +U q AND q ), Grid-connected reactive power Q e The calculation formula used is: Q c =1.5(U q I d -U d I q )。 3. The virtual synchronous machine optimization control method based on frequency and phase feedforward compensation according to claim 1 is characterized in that: The output voltage reference instruction E in step 2 d The calculation formula used is: E d =E0+(Q ref -Q c )k q , Output voltage reference instruction E q The calculation formula used is: E q ＝0。 4. The virtual synchronous machine optimization control method based on frequency and phase feedforward compensation according to claim 1 is characterized in that: The calculation formula for the angular frequency deviation Δω in step 3 is: Where s is the Laplace operator.

5. The virtual synchronous machine optimization control method based on frequency and phase feedforward compensation according to claim 1 is characterized in that: Grid-connected active power deviation ΔP in step 4 e The calculation formula is: ΔP c =P ref -P c , Output angular frequency compensation Δω b The calculation formula used is: The calculation formula for the virtual synchronous machine output angular frequency ω is: oh = I see b +Dω+ω0, Where s is the Laplace operator.

6. The virtual synchronous machine optimization control method based on frequency and phase feedforward compensation according to claim 1 is characterized in that: Output phase angle compensation Δθ in step 5 a The calculation formula used is: Where s is the Laplace operator.

7. The virtual synchronous machine optimization control method based on frequency and phase feedforward compensation according to claim 1 is characterized in that: The calculation formula for the virtual synchronous machine output phase angle θ in step 6 is: Where s is the Laplace operator.

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