Control method and control device for realizing virtual permanent magnet synchronous generator

Abstract

The invention discloses a control method and a control device for realizing a virtual permanent magnet synchronous generator, and relates to the technical field of power supplies. The power level topology of the virtual permanent magnet synchronous generator is a three-phase inverter, the d-axis component of a reference resultant vector of a grid-side three-phase bridge arm is zero, the q-axis component is npXdc psi f, np is the number of virtual pole pairs, Xdc is the physical quantity of a direct current side, and psi f is a virtual flux linkage. And the output quantity is adjusted by controlling the number np of the virtual pole pairs and the virtual flux linkage psi f. According to the method, the control strategy of the network-forming inverter is simplified, a phase-locked loop is not needed, control resources are saved, the application range is wide, and implementation is easy.

Description

Technical Field

[0001] The present invention relates to the technical field of power supplies, and in particular to a control method and a control device for realizing a virtual permanent magnet synchronous generator. Background Art

[0002] With the continuous depletion of fossil energy, new energy technologies such as photovoltaics and wind power are developing rapidly. More and more new energy devices are being integrated into the grid through power electronic devices. Traditional power electronic devices, due to their lack of inertia, cannot directly participate in regulating grid frequency and bus voltage. This reduces the grid's inertia and significantly impacts the stability of the entire grid system. To address this issue, grid-connected inverter technology has emerged. Its core is to simulate the active power / frequency and reactive power / voltage droop characteristics of synchronous motors. This allows them to effectively stabilize grid frequency and bus voltage, just like the synchronous motors in traditional thermal power plants, ensuring safe and stable operation of electrical equipment.

[0003] Early grid-type inverter technology solutions, such as the virtual synchronous generator proposed by Qing-Chang Zhong et al. in 2011, utilized the flux, voltage, and torque equations of the synchronous motor. However, the control model was relatively complex and occupied a large amount of software resources. Subsequent research has attempted to simplify the method. For example, in 2016, Mahdi Ashabani et al. proposed a virtual motor control method without a phase-locked loop to eliminate the phase-locked loop, in 2020, Catalin Arghir et al. proposed using DC capacitors to simulate inertia, and in 2023, Yun Yu et al. introduced fractional-order derivatives to suppress oscillations. However, these methods still require solving motor equations or involve complex operations (such as square and fractional differentials), making it difficult to improve system response speed and real-time performance. Patent No. US2024 / 0079978A1, published in 2024, proposed a control method for a virtual synchronous generator. However, this method uses a power reference value as a method for generating the virtual electrical angle, which increases control complexity, fails to fully utilize the advantages of the three-phase voltage source inverter hardware topology, and increases control costs.

[0004] It can be seen that the current existing virtual synchronous generator solutions all rely on motor equations or complex mathematical transformations, resulting in three major problems: large software resource usage, slow dynamic response speed and high hardware cost. Summary of the Invention

[0005] One of the objectives of the present invention is to provide a control method for realizing a virtual permanent magnet synchronous generator in response to the problems in the above background technology.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solution: a control method for realizing a virtual permanent magnet synchronous generator, wherein the generator is based on a three-phase inverter topology and includes a DC side circuit, a three-phase bridge circuit, and a grid-side filter circuit; the method comprises the following steps:

[0007] (1) controlling the d-axis components of the reference synthetic vectors of the three bridge arms of the three-phase bridge circuit so that their absolute values ​​do not exceed a preset first error threshold;

[0008] (2) controlling the q-axis components of the reference synthetic vectors of the three bridge arms of the three-phase bridge circuit so that they are proportional to the physical quantity on the DC side and the deviation from the proportional value does not exceed a preset second error threshold, wherein the proportional value is determined by the product of the number of virtual pole pairs and the virtual flux linkage;

[0009] (3) Controlling the three bridge arms of the three-phase bridge circuit to reference the synthetic vectors to satisfy a preset relationship, and generating a synchronous rotation angle based on the time integral of the physical quantity on the DC side, wherein the integral coefficient is the number of virtual pole pairs.

[0010] Preferably, in step (1), the synthetic vector X ref The d-axis component X dref Satisfies the following relationship: |X dref |≤δ d ; In step (2), the synthetic vector X ref The q-axis component X qref Satisfies the following relationship: |X qref -n p X dc ψ f |≤δ q ; In step (3), the preset relationship is:

[0011]

[0012] Among them, n p is the number of virtual pole pairs, n p ∈R;ψ f is the virtual magnetic flux, ψ f ∈R;δ,δ d and δ q is the upper limit of the error, which is a positive number; θ is the virtual electrical angle, and θ=∫n p X dc dt;C T is the coordinate transformation coefficient; X dc is the physical quantity on the DC side; X a ,X b and X c is the instantaneous value of the AC output of the three-phase bridge circuit; X aref ,X bref and X crefIt is the reference value of the AC output of the three bridge arms of the three-phase bridge circuit.

[0013] Among them, δ d and δ q Satisfies the following relationship: d =0 and / or δ q =0.

[0014] Preferably, the DC side physical quantity X dc is the actual capacitor voltage v dc Or the actual inductor current i dc ; Or, the DC side physical quantity X dc is the virtual capacitor voltage v dc Or virtual inductor current i dc .

[0015] More preferably, the DC side physical quantity X dc is the virtual capacitor voltage v dc , its voltage equation satisfies the following relationship:

[0016]

[0017] Among them, C v is the virtual capacitor, I s is the actual input current on the DC side, i q It is the q-axis component of the synthetic vector i of the three-phase measured current on the AC side of the three-phase bridge circuit.

[0018] More preferably, the DC side physical quantity X dc is the virtual inductor current i dc , its current equation satisfies the following relationship:

[0019]

[0020] Among them, L v is the virtual inductor, V in is the actual input voltage on the DC side, v q is the q-axis component of the three-phase measured voltage synthesis vector v on the AC side of the three-phase inverter.

[0021] As a second aspect of the present invention, when the three-phase inverter is a three-phase voltage source inverter, the three-phase voltage source inverter includes a DC side circuit (I), a three-phase bridge circuit (II) and a grid-side filter circuit (III), and the control method includes the following steps:

[0022] (1) Control the three-phase bridge circuit three-arm reference voltage synthesis vector V ref The d-axis component V dref Satisfies the following relationship: |V dref |≤δ d ;

[0023] (2) Control the three-phase bridge circuit three-arm reference voltage synthesis vector V ref The q-axis component V qref Satisfies the following relationship: |V qref -n p v dc ψ f |≤δ q ;

[0024] (3) Control the three-phase bridge circuit three-arm reference voltage synthesis vector V ref Satisfies the following relationship:

[0025]

[0026] Among them, v dc is the DC side capacitor voltage; v a ,v b and v c is the instantaneous value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit; v aref ,v bref and v cref is the reference value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit; θ is the virtual electrical angle, and θ=∫n p v dc dt; coordinate transformation coefficient C T The value is 2 / 3 or 1;

[0027] When the three-phase inverter is a three-phase voltage source inverter, the instantaneous value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit is v a , v b and v c The angular frequency is ω v =n p v dc , and the frequency f v =n p v dc / 2π; the instantaneous value of the midpoint voltage v a , v b and v c Satisfies the following relationship:

[0028]

[0029] Among them, the switching functions of the three bridge arms of the three-phase bridge circuit are S 1i , i∈{a,b,c}, when S 1i When it is 1, the upper bridge arm is turned on and the lower bridge arm is turned off; when S 1i When the value is 0, the upper arm is turned off and the lower arm is turned on.

[0030] Preferably, by adjusting the virtual pole pair number n of the virtual permanent magnet synchronous generator p and virtual magnetic flux ψ f The output is controlled by adjusting the

[0031] As a third aspect of the present invention, when the three-phase inverter is a three-phase current source inverter, the three-phase current source inverter includes a DC side inductor circuit (I), a three-phase bridge circuit (II) and a grid-side filter circuit (III), and the control method includes the following steps:

[0032] (1) Control the output current reference vector i of the three bridge arms of the three-phase bridge circuit ref The d-axis component i dref Satisfies the following relationship: |i dref |≤δ d ;

[0033] (2) Control the output current reference vector i of the three bridge arms of the three-phase bridge circuit ref The q-axis component i qref Satisfies the following relationship: |i qref -n p i dc ψ f |≤δ q ;

[0034] (3) Control the output current reference synthesis vector i of the three bridge arms of the three-phase bridge circuit ref Satisfies the following relationship:

[0035]

[0036] Among them, i dc is the DC side inductor current; i a ,i b and i c is the instantaneous value of the output current at the midpoint of the three bridge arms of the three-phase bridge circuit; i aref ,i bref and i cref is the reference value of the output current at the midpoint of the three bridge arms of the three-phase bridge circuit; θ is the virtual electrical angle, and θ=∫n p i dc dt; coordinate transformation coefficient C T The value is 2 / 3 or 1;

[0037] When the three-phase inverter is a three-phase current source inverter, the instantaneous value of the output current at the midpoint of the three bridge arms of the three-phase bridge circuit is i ia ,i ib and i ic The angular frequency is ω i =n p idc , and the frequency f i =n p i dc / 2π; the instantaneous value of the midpoint output current i ia ,i ib and i ic Satisfies the following relationship:

[0038]

[0039] Among them, the switching functions S of the three bridge arms of the three-phase bridge circuit are 2i =S ip -S in , i∈{a,b,c}, S ip Represents the switching function of the upper arm switch tube, S ip =1 means the upper arm switch is turned on, S ip =0 means the upper arm switch is turned off; S in Represents the switching function of the lower bridge arm switch tube, S in =1 means the lower bridge arm switch is turned on, S in =0 means the lower arm switch is turned off.

[0040] Preferably, by adjusting the virtual pole pair number n of the virtual permanent magnet synchronous generator p and virtual magnetic flux ψ f The output is controlled by adjusting the

[0041] In addition, the present invention also provides a control device for realizing a virtual permanent magnet synchronous generator, which includes:

[0042] Signal acquisition unit, used to obtain DC side physical quantity X dc And the instantaneous value X of the AC output of the three-phase bridge circuit a , X b , X c ;

[0043] A vector control unit is used to control the d-axis component of the AC output synthetic vector to meet

[0044] |X dref |≤δ d ; and the q-axis component of the AC output synthesis vector satisfies |X qref -n p X dc ψ f |≤δ q ;

[0045] Angle generation unit, used to generate virtual electrical angle based on integral operation: θ = ∫n p X dc dt;

[0046] The modulation signal output unit is used to output a modulation signal according to the virtual electrical angle θ and the synthetic vector reference value X ref , generate three-phase bridge arm modulation signal and drive the switch tube action of the three-phase bridge circuit;

[0047] The control device operates based on the above-mentioned control method.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The control method of the present invention controls the d-axis components of the reference synthetic vectors of the three bridge arms of the three-phase bridge circuit to meet a preset relationship, and controls the q-axis components of the reference synthetic vectors of the three bridge arms of the three-phase bridge circuit to meet a preset relationship, so that the control scheme is simple, easy to implement, and occupies less control resources.

[0050] (2) The control method of the present invention converts the d-axis component and the q-axis component of the reference synthetic vector of the three bridge arms of the three-phase bridge circuit into a three-phase coordinate system through angle transformation, wherein the physical quantity on the DC side is obtained through a voltage measurement module or a current measurement module, and the angle θ can be obtained without a phase-locked loop, which is simple to calculate. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A typical topology of a three-phase voltage source type virtual permanent magnet synchronous generator applicable to the control method of embodiment 2 of the present invention;

[0052] Figure 2 The control method of embodiment 2 of the present invention is applied to Figure 1 The grid voltage waveform of the circuit;

[0053] Figure 3 The control method of embodiment 2 of the present invention is applied to Figure 1 The grid current waveform of the circuit;

[0054] Figure 4 This is a topological diagram of a three-phase voltage source virtual permanent magnet synchronous generator with a Γ-type filter according to the present invention;

[0055] Figure 5 This is a topological diagram of a three-phase voltage source virtual permanent magnet synchronous generator with a T-type filter according to the present invention;

[0056] Figure 6 Schematic diagram of a three-phase voltage source virtual permanent magnet synchronous generator with a PI controller according to the present invention;

[0057] Figure 7 The frequency and active power waveforms of the three-phase voltage source virtual permanent magnet synchronous generator with a PI controller of the present invention are shown in FIG.

[0058] Figure 8A typical topology structure of a three-phase current source type virtual permanent magnet synchronous generator applicable to the control method of embodiment 2 of the present invention;

[0059] Figure 9 This is a topological diagram of a three-phase current source type virtual permanent magnet synchronous generator with a Γ-type filter according to the present invention;

[0060] Figure 10 This is a topological diagram of the three-phase current source type virtual permanent magnet synchronous generator with a π-type filter of the present invention.

[0061] Figure 11 A typical topology of a three-phase voltage source type virtual permanent magnet synchronous generator applicable to the control method of embodiment 3 of the present invention;

[0062] Figure 12 The control method of embodiment 3 of the present invention is applied to Figure 11 The grid voltage waveform of the circuit;

[0063] Figure 13 This is a typical topology structure of a three-phase current source type virtual permanent magnet synchronous generator to which the control method of embodiment 4 of the present invention is applicable. DETAILED DESCRIPTION

[0064] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and drawings. The contents mentioned in the embodiments are not intended to limit the present invention.

[0065] It should be noted in advance that the drawings in this disclosure are schematic diagrams only and are not necessarily drawn to scale. Identical reference numerals in the drawings denote identical or similar parts, and therefore repeated descriptions thereof will be omitted. Some of the blocks shown in the drawings represent functional entities and do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented using software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontrollers.

[0066] Example 1

[0067] This embodiment provides a control method for implementing a virtual permanent magnet synchronous generator, which is used to control all switching tubes of the virtual permanent magnet synchronous generator. Its topology is a three-phase inverter, and the three-phase inverter includes a DC side circuit, a three-phase bridge circuit, and a grid-side filter circuit. The control method specifically includes the following steps:

[0068] Control the three bridge arms of the three-phase bridge circuit with reference to the synthetic vector X ref The d-axis component X dref Satisfies the following relationship:

[0069] |Xdref |≤δ d ;

[0070] And control the three bridge arms of the three-phase bridge circuit reference synthetic vector X ref The q-axis component X qref Satisfies the following relationship:

[0071] |X qref -n p X dc ψ f |≤δ q ;

[0072] And control the three bridge arms of the three-phase bridge circuit reference synthetic vector X ref Satisfies the following relationship:

[0073]

[0074] Among them, n p is the number of virtual pole pairs, n p ∈R;ψ f is the virtual magnetic flux, ψ f ∈R;δ,δ d and δ q is the upper limit of the error, which is a positive number; θ is the virtual electrical angle, and θ=∫n p X dc dt;C T is the coordinate transformation coefficient; X dc is the DC side detection quantity; X a ,X b and X c is the instantaneous value of the AC output of the three-phase bridge circuit; X aref ,X bref and X cref It is the reference value of the AC output of the three bridge arms of the three-phase bridge circuit.

[0075] Among them, δ d and δ q Satisfies the following relationship,

[0076] δ d =0 and / or δ q =0.

[0077] Preferably, X dref and X qref Satisfies the following relationship,

[0078] X dref =0 and / or X qref =n p X dc ψ f .

[0079] Furthermore, the DC side physical quantity X dc is the actual capacitor voltage v dc Or the actual inductor current i dc .

[0080] Or, the DC side physical quantity X dc is the virtual capacitor voltage v dc Or virtual inductor current i dc .

[0081] By calculating the virtual pole pair number n of the virtual permanent magnet synchronous generator p and virtual magnetic flux ψ f The output is controlled by adjusting the

[0082] The provided control method for the virtual synchronous generator can work in both the generator state and the motor state.

[0083] Example 2

[0084] The control method provided in this embodiment is used to control all the switch tubes of the three-phase voltage source type virtual permanent magnet synchronous generator. Figure 1 This is a typical topology of a three-phase voltage source virtual permanent magnet synchronous generator to which the control method of this embodiment is applicable.

[0085] like Figure 1 As shown, the topology of the three-phase voltage source virtual permanent magnet synchronous generator is a three-phase voltage source inverter, which includes a DC side capacitor circuit (I), a three-phase bridge circuit (II) and a grid-side filter circuit (III), wherein:

[0086] The DC link capacitance circuit (I) includes an equivalent parallel conductance G and a DC link capacitance C;

[0087] The three-phase bridge circuit (II) includes a switch tube S1, a switch tube S2, a switch tube S3, a switch tube S4, a switch tube S5 and a switch tube S6;

[0088] The grid-side filter circuit (III) includes a filter inductor L and an equivalent series impedance R.

[0089] It should be noted that Figure 1 It is just a typical topological structure diagram of the three-phase voltage source type virtual permanent magnet synchronous generator applicable to the control method of this embodiment, wherein the grid-side filter circuit (III) can also be designed as a Γ type or T type structure; the three-phase voltage source type topological structure can also be a three-level structure or a multi-level structure; the DC side capacitor voltage v dcThe voltage between the positive and negative terminals on the DC side can be the voltage of a single capacitor or the sum of the voltages of multiple capacitors connected in series. The specific topology employed in the control method of this embodiment is not limited and can be selected by those skilled in the art as needed. The present invention further provides some other topologies for virtual permanent magnet synchronous generators.

[0090] The specific control method of the three-phase voltage source virtual permanent magnet synchronous generator of this embodiment includes:

[0091] Control the three-phase bridge circuit three-arm reference voltage synthesis vector V ref The d-axis component V dref Satisfies the following relationship:

[0092] |V dref |≤δ d ;

[0093] And control the three bridge arm reference voltage synthesis vector V of the three-phase bridge circuit ref The q-axis component V qref Satisfies the following relationship:

[0094] |V qref -n p v dc ψ f |≤δ q ;

[0095] And control the three bridge arm reference voltage synthesis vector V of the three-phase bridge circuit ref Satisfies the following relationship:

[0096]

[0097] Among them, v dc is the DC side capacitor voltage; v a ,v b and v c is the instantaneous value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit; v aref ,v bref and v cref is the reference value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit; θ is the virtual electrical angle, and θ=∫n p v dc dt; coordinate transformation coefficient C T The value is 2 / 3 or 1.

[0098] Furthermore, the instantaneous values ​​of the voltages at the midpoints of the three bridge arms of the three-phase bridge circuit are v a , v b and v c The angular frequency is ω v =n pv dc , and the frequency f v =n p v dc / 2π.

[0099] Furthermore, the instantaneous value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit is v a , v b and v c Satisfies the following relationship:

[0100]

[0101] Among them, the switching functions of the three bridge arms of the three-phase bridge circuit are S 1i , i∈{a,b,c}, when S 1i When it is 1, the upper bridge arm is turned on and the lower bridge arm is turned off; when S 1i When the value is 0, the upper arm is turned off and the lower arm is turned on.

[0102] Figure 1 The PWM modulator in the circuit uses SPWM modulation mode to calculate the voltage reference value v aref 、v bref and v cref As the modulation wave, the triangle wave is used as the carrier wave. When the instantaneous value of the modulation wave v aref When the modulating wave instantaneous value v is greater than the carrier, the switch tube S1 is turned on and the switch tube S2 is turned off. Otherwise, the switch tube S1 is turned off and the switch tube S2 is turned on. bref When the modulating wave instantaneous value v is greater than the carrier, the switch tube S3 is turned on and the switch tube S4 is turned off. Otherwise, the switch tube S3 is turned off and the switch tube S4 is turned on. cref When the voltage is greater than the carrier, the switch tube S5 is turned on and the switch tube S6 is turned off; otherwise, the switch tube S5 is turned off and the switch tube S6 is turned on.

[0103] Figure 2 The control method of this embodiment is shown as being applied to Figure 1 The grid voltage waveform u of the circuit a 、u b and u c , it can be seen that the three-phase grid voltage waveform is symmetrical and sinusoidal. Figure 3 The control method of this embodiment is shown as being applied to Figure 1 The grid current waveform i of the circuit ga 、i gb and i gc , it can be seen that the three-phase grid current waveform is symmetrical and sinusoidal.

[0104] Furthermore, by calculating the virtual pole pair number n of the virtual permanent magnet synchronous generator p and virtual magnetic flux ψ fThe output is controlled by adjusting the output. This control method is simple, easy to implement, and has low control cost. The virtual permanent magnet synchronous generator itself can obtain the angle θ without a phase-locked loop, and the calculation is simple.

[0105] Furthermore, the number of virtual pole pairs n p As the control quantity, PI controller is used to adjust n p To compensate for the angular frequency ω v The change of n p v dc As feedback quantity, such as Figure 6 The figure shows a schematic diagram of a virtual permanent magnet synchronous generator with a PI controller according to the present invention, wherein Z load is a three-phase symmetrical load. The PI controller transfer function is

[0106]

[0107] Among them, K p is the proportionality coefficient, K i is the integral coefficient. The PI controller can be used to control the angular frequency and grid frequency. The grid frequency and active power change as follows Figure 7 As shown, where f v is the grid frequency, P is the active power output by the virtual synchronous generator, and it can be seen that the load Z load When the active power changes, the active power is automatically adjusted, and the grid frequency f v Basically unchanged, stable at the given frequency value f ref .

[0108] Preferably, the filter in the three-phase voltage type virtual permanent magnet synchronous generator can be of Γ type, such as Figure 4 As shown, it can also be T-shaped, such as Figure 5 shown.

[0109] Preferably, the virtual permanent magnet synchronous generator can also be a three-phase current source type, and its typical structure is as follows: Figure 8 As shown, the filter circuit can also be Γ type and Π type, respectively. Figure 9 and Figure 10 shown.

[0110] Example 3

[0111] The control method provided in this embodiment is used to control all the switch tubes of the three-phase voltage source type virtual permanent magnet synchronous generator, and calculate the virtual electrical angle θ using the virtual capacitor. Figure 11 This is a typical structure of a three-phase voltage source type virtual permanent magnet synchronous generator to which the control method of this embodiment is applicable. dc is the virtual capacitor voltage v dc , its voltage equation satisfies the following relationship:

[0112]

[0113] Among them, C v is the virtual capacitor, I s is the actual input current on the DC side, i q The composite vector of the three-phase measured current on the AC side of the three-phase bridge circuit The q-axis component of .

[0114] Figure 12 The control method of this embodiment is shown as being applied to Figure 11 The grid voltage waveform u of the circuit a 、u b and u c , grid current waveform i ga 、i gb and i gc ,It can be seen that the grid voltage and current waveforms are symmetrical and sinusoidal.

[0115] Furthermore, the grid-side angular frequency ω can be adjusted based on the number of virtual pole pairs. v , the virtual flux is used to adjust the grid-side output voltage.

[0116] Example 4

[0117] The control method provided in this embodiment is used to control all the switch tubes of the three-phase current source type virtual permanent magnet synchronous generator, and calculate the virtual electrical angle θ using the virtual inductance. Figure 13 This is a typical structure of a three-phase current source type virtual permanent magnet synchronous generator to which the control method of this embodiment is applicable. dc is the virtual inductor current i dc , its current equation satisfies the following relationship:

[0118]

[0119] Here, L v is the virtual inductor, V in is the actual input voltage on the DC side, v q The composite vector of the three-phase voltage measured on the AC side of the three-phase inverter The q-axis component of f ref is the frequency reference value, V ref is the grid side voltage reference value, u rms It is the effective value of the line voltage or phase voltage of the AC side grid voltage.

[0120] Preferably, the PWM modulator in the virtual permanent magnet synchronous generator can be a modulation method such as SPWM or SVPWM given in Section I to Section III of the paper "Simple Analytical and Graphical Methods for Carrier-Based PWM-VSI Drives" published by Ahmet M. Hava et al. in 1999.

[0121] The control method for realizing a virtual permanent magnet synchronous generator provided in the above embodiments mainly comprises the following technical principles: ref The d-axis component X dref Satisfies the relationship: |X dref |≤δ d ; and control the three bridge arms of the three-phase bridge circuit reference synthetic vector X ref The q-axis component X qref Satisfies the relationship: |X qref -n p X dc ψ f |≤δ q , where X dref =0,X qref =n p X dc ψ f This makes the method simple to control, easy to implement, and occupies less control resources.

[0122] In addition, the three bridge arms of the three-phase bridge circuit refer to the synthetic vector X ref The d-axis component and q-axis component of the θ are transformed into the three-phase coordinate system through the angle θ, where θ = ∫n p X dc dt,X dc The angle θ can be obtained through a voltage measurement module or a current measurement module without a phase-locked loop, and the calculation is simple.

[0123] In general, the present invention simplifies the control strategy of the grid-type inverter, does not require a phase-locked loop, saves control resources, has a wide range of applications, and is easy to implement.

[0124] In order to make it easier for ordinary technicians in this field to understand the improvements of the present invention over the prior art, some drawings and descriptions of the present invention have been simplified, and the above-mentioned embodiments are preferred implementation schemes of the present invention. In addition, the present invention can also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the scope of protection of the present invention.

Claims

1. A control method for realizing a virtual permanent magnet synchronous generator, wherein the generator is based on a three-phase inverter topology and includes a DC side circuit, a three-phase bridge circuit, and a grid-side filter circuit; characterized in that: The following steps are involved: (1) controlling the d-axis components of the reference synthetic vectors of the three bridge arms of the three-phase bridge circuit so that their absolute values ​​do not exceed a preset first error threshold; (2) controlling the q-axis components of the reference synthetic vectors of the three bridge arms of the three-phase bridge circuit so that they are proportional to the physical quantity on the DC side and the deviation from the proportional value does not exceed a preset second error threshold, wherein the proportional value is determined by the product of the number of virtual pole pairs and the virtual flux linkage; (3) Controlling the three bridge arms of the three-phase bridge circuit to reference the synthetic vectors to satisfy a preset relationship, and generating a synchronous rotation angle based on the time integral of the physical quantity on the DC side, wherein the integral coefficient is the number of virtual pole pairs.

2. The control method for realizing a virtual permanent magnet synchronous generator according to claim 1, characterized in that: In step (1), the synthetic vector X ref The d-axis component X dref Satisfies the following relationship: |X dref |≤δ d ; In step (2), the synthetic vector X ref The q-axis component X qref Satisfies the following relationship: |X qref -n p X dc ψ f |≤δ q ; In step (3), the preset relationship is: Among them, n p is the number of virtual pole pairs, n p ∈R;ψ f is the virtual magnetic flux, ψ f ∈R;δ,δ d and δ q is the upper limit of the error, which is a positive number; θ is the virtual electrical angle, and θ=∫n p X dc dt;C T is the coordinate transformation coefficient; X dc is the physical quantity on the DC side; X a ,X b and X c is the instantaneous value of the AC output of the three-phase bridge circuit; X aref ,X bref and X cref It is the reference value of the AC output of the three bridge arms of the three-phase bridge circuit.

3. The control method for realizing a virtual permanent magnet synchronous generator according to claim 2, characterized in that: δ d and δ q Satisfies the following relationship: d =0 and / or δ q =0.

4. The control method for realizing a virtual permanent magnet synchronous generator according to claim 2, characterized in that: The DC side physical quantity X dc is the actual capacitor voltage v dc Or the actual inductor current i dc ; Or, the DC side physical quantity X dc is the virtual capacitor voltage v dc Or virtual inductor current i dc .

5. The control method for realizing a virtual permanent magnet synchronous generator according to claim 4, characterized in that: The DC side physical quantity X dc is the virtual capacitor voltage v dc , its voltage equation satisfies the following relationship: Among them, C v is the virtual capacitor, I s is the actual input current on the DC side, i q It is the q-axis component of the synthetic vector i of the three-phase measured current on the AC side of the three-phase bridge circuit.

6. The control method for realizing a virtual permanent magnet synchronous generator according to claim 4, characterized in that: The DC side physical quantity X dc is the virtual inductor current i dc , its current equation satisfies the following relationship: Among them, L v is the virtual inductor, V in is the actual input voltage on the DC side, v q is the q-axis component of the three-phase measured voltage synthesis vector v on the AC side of the three-phase inverter.

7. The control method for realizing a virtual permanent magnet synchronous generator according to claim 2, characterized in that: When the three-phase inverter is a three-phase voltage source inverter, all Xs represent voltages, and the three-phase voltage source inverter includes a DC side circuit, a three-phase bridge circuit, and a grid-side filter circuit. The control method includes the following steps: (1) Control the three-phase bridge circuit three-arm reference voltage synthesis vector V ref The d-axis component V dref Satisfies the following relationship: |V dref |≤δ d ; (2) Control the three-phase bridge circuit three-arm reference voltage synthesis vector V ref The q-axis component V qref Satisfies the following relationship: |V qref -n p v dc ψ f |≤δ q ; (3) Control the three-phase bridge circuit three-arm reference voltage synthesis vector V ref Satisfies the following relationship: Among them, v dc is the DC side capacitor voltage; v a ,v b and v c is the instantaneous value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit; v aref ,v bref and v cref is the reference value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit; θ is the virtual electrical angle, and θ=∫n p v dc dt; coordinate transformation coefficient C T The value is 2 / 3 or 1; When the three-phase inverter is a three-phase voltage source inverter, the instantaneous value of the midpoint voltage of the three bridge arms of the three-phase bridge circuit is v a , v b and v c The angular frequency is ω v =n p v dc , and the frequency f v =n p v dc / 2π; the instantaneous value of the midpoint voltage v a , v b and v c Satisfies the following relationship: Among them, the switching functions of the three bridge arms of the three-phase bridge circuit are S 1i , i∈{a,b,c}, when S 1i When it is 1, the upper bridge arm is turned on and the lower bridge arm is turned off; when S 1i When the value is 0, the upper arm is turned off and the lower arm is turned on.

8. The control method for realizing a virtual permanent magnet synchronous generator according to claim 2, characterized in that: When the three-phase inverter is a three-phase current source inverter, all Xs represent currents, and the three-phase current source inverter includes a DC side inductor circuit, a three-phase bridge circuit, and a grid-side filter circuit. The control method includes the following steps: (1) Control the output current reference synthesis vector i of the three bridge arms midpoint of the three-phase bridge circuit ref The d-axis component i dref Satisfies the following relationship: |i dref |≤δ d ; (2) Control the output current reference vector i of the three bridge arms of the three-phase bridge circuit ref The q-axis component i qref Satisfies the following relationship: |i qref -n p i dc ψ f |≤δ q ; (3) Control the output current reference synthesis vector i of the three bridge arms of the three-phase bridge circuit ref Satisfies the following relationship: Among them, i dc is the DC side inductor current; i a ,i b and i c is the instantaneous value of the output current at the midpoint of the three bridge arms of the three-phase bridge circuit; i aref ,i bref and i cref is the reference value of the output current at the midpoint of the three bridge arms of the three-phase bridge circuit; θ is the virtual electrical angle, and θ=∫n p i dc dt; coordinate transformation coefficient C T The value is 2 / 3 or 1; When the three-phase inverter is a three-phase current source inverter, the instantaneous value of the output current at the midpoint of the three bridge arms of the three-phase bridge circuit is i ia ,i ib and i ic The angular frequency is ω i =n p i dc , and the frequency f i =n p i dc / 2π; the instantaneous value of the midpoint output current i ia ,i ib and i ic Satisfies the following relationship: Among them, the switching functions S of the three bridge arms of the three-phase bridge circuit are 2i =S ip -S in , i∈{a,b,c}, S ip Represents the switching function of the upper arm switch tube, S ip =1 means the upper arm switch is turned on, S ip =0 means the upper arm switch is turned off; S in Represents the switching function of the lower bridge arm switch tube, S in =1 means the lower bridge arm switch is turned on, S in =0 means the lower arm switch is turned off.

9. The control method for realizing a virtual permanent magnet synchronous generator according to claim 2, characterized in that: By the virtual pole pair number n of the virtual permanent magnet synchronous generator p and virtual magnetic flux ψ f The output is controlled by adjusting the 10. A control device for realizing a virtual permanent magnet synchronous generator, characterized in that: include: Signal acquisition unit, used to obtain DC side physical quantity X dc And the instantaneous value X of the AC output of the three-phase bridge circuit a , X b , X c ; A vector control unit is used to control the d-axis component of the AC output synthetic vector to satisfy |X dref |≤δ d ; and the q-axis component of the AC output synthesis vector satisfies |X qref -n p X dc ψ f |≤δ q ; Angle generation unit, used to generate virtual electrical angle based on integral operation: θ = ∫n p X dc dt; a modulation signal output unit for outputting a signal according to the virtual electrical angle θ and the synthetic vector reference value X ref , generating a three-phase bridge arm modulation signal and driving the switch tube of the three-phase bridge circuit; the control device operates based on the control method described in any one of claims 1-9.

Images