Modeling and control method of Vienna rectifier under inductance imbalance

Abstract

The invention discloses a modeling and control method for a Vienna rectifier under inductance imbalance, and belongs to the technical field of electric energy conversion. Compared with a traditional double-closed-loop control method, the influence of unbalanced inductance is considered when mathematical modeling is carried out on the Vienna rectifier, three-phase unbalanced inductance information is introduced into the control method, and the problem of alternating current side current distortion caused by three-phase inductance imbalance is restrained; the control effect under the three-phase inductance balance state is consistent with the conventional double-closed-loop control effect, the good alternating current side current quality can still be maintained when the inductance of a certain phase changes greatly, the rectifier has good stability, controller parameters of a current loop do not need to be finely set, and the cost is reduced. And more complex working conditions in production can be coped with.

Description

Technical Field

[0001] The invention relates to the technical field of electric energy conversion, and in particular to a modeling method of a Vienna rectifier under unbalanced inductance. Background Art

[0002] With the rapid development of the times and the continuous advancement of science and technology, new energy equipment is also constantly being updated. As an important power conversion circuit, the rectifier circuit exists in all aspects of life. Compared with new energy equipment, it is an indispensable part. However, the nonlinear rectification method will generate a large amount of harmonics and reactive power injected into the power grid, resulting in a decrease in the power quality of the power system. Installing reactive compensation and filtering equipment on the grid side to uniformly improve the power quality is a solution; another method is to add a power factor correction circuit to the power electronic equipment to solve the problem on the application side. The Vienna rectifier is an excellent three-level rectifier topology that can not only provide a stable DC voltage output for the subsequent stage or load, but also realize the power factor correction function of the input current tracking the grid voltage. It has been widely used in medium and high power fields with unidirectional energy flow, such as wind power generation systems, electric vehicle charging systems, aviation power supplies, etc.

[0003] However, due to the limitations of the Vienna rectifier's own topology, the presence of the AC-side filter inductor will cause a certain phase difference between the input voltage and the input current, which is also the main reason for its current distortion. Device aging and improper selection of inductor core materials will affect the performance of the inductor, resulting in a large gap between the actual inductance value and the inductance value in the system model, causing the grid-side current distortion of the rectifier to increase, resulting in the overall performance of the rectifier to deteriorate. In some cases where multiple rectifiers are connected in parallel, the imbalance of the three-phase filter inductance may cause circulating current between the rectifiers, reducing the efficiency of the system.

[0004] At present, the control method for Vienna rectifier mainly adopts a dual closed-loop control strategy of voltage outer loop control and current inner loop control. However, this control strategy cannot effectively guarantee the current quality on the AC side when the inductance value of a certain phase of the rectifier changes significantly. It is very necessary to adopt an improved control method to suppress the current distortion caused by inductance change and maintain the input performance of Vienna rectifier. To this end, a modeling and control method of Vienna rectifier under inductance imbalance is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is: how to realize the operation control of the Vienna rectifier under the condition of unbalanced inductance, introduce the information of the three-phase unbalanced inductance into the control method, solve the problem of aggravated current distortion on the AC side caused by inductance change under the condition of unbalanced three-phase inductance, make the rectifier have better stability, and provide a modeling method of the Vienna rectifier under unbalanced inductance.

[0006] The present invention solves the above technical problems through the following technical solutions, and the present invention comprises the following steps:

[0007] S1: Establish the mathematical model of the three-phase static abc coordinate system of the Vienna rectifier AC side;

[0008] S2: Using Clarke transformation, the mathematical model of the three-phase static abc coordinate system of the AC side of the Vienna rectifier is transformed into a mathematical model of the two-phase static αβ coordinate system;

[0009] S3: Using Park transformation, the mathematical model in the two-phase stationary αβ coordinate system is converted into a mathematical model in the two-phase rotating dq coordinate system and simplified to obtain a simplified mathematical model in the two-phase rotating dq coordinate system.

[0010] Furthermore, in step S1, the expression of the mathematical model of the three-phase stationary abc coordinate system of the AC side of the Vienna rectifier is established as follows:

[0011]

[0012] Among them, L a , L b , L c is the inductance of each phase on the AC side of Vienna rectifier; e a 、e b 、e c is the input voltage of each phase of Vienna rectifier in the three-phase stationary abc coordinate system; i a 、i b 、i c is the input current of each phase of Vienna rectifier in the three-phase stationary abc coordinate system; is the differential of each phase input current with respect to time; U aN , U bN , U cN is the voltage of the diode clamping point at each phase input end of the Vienna rectifier relative to the neutral point on the AC side in the three-phase stationary abc coordinate system; R is the load resistance on the DC side.

[0013] Furthermore, in step S2, the expression of the mathematical model in the two-phase stationary αβ coordinate system is converted as follows:

[0014]

[0015] in:

[0016]

[0017] Among them, e α 、e β is the input voltage of the α-axis and β-axis of the Vienna rectifier in the two-phase stationary αβ coordinate system; i α 、i β is the input current of the α-axis and β-axis of the Vienna rectifier in the two-phase stationary αβ coordinate system; is the differential of the input current of the α-axis and β-axis with respect to time; U α , U β are the α-axis and β-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point on the AC side in the two-phase stationary αβ coordinate system.

[0018] Furthermore, in step S3, the expression of the mathematical model in the two-phase rotating dq coordinate system is:

[0019]

[0020] in:

[0021]

[0022] Among them, e d 、e q is the input voltage of the Vienna rectifier on the d-axis and q-axis in the two-phase rotating dq coordinate system; i d 、i q is the input current of the Vienna rectifier on the d-axis and q-axis in the two-phase rotating dq coordinate system; is the differential of the d-axis and q-axis input current with respect to time; U d , U q are the d-axis and q-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point of the AC side in the two-phase rotating dq coordinate system; ω is the angular frequency of the industrial frequency AC power, and θ is the angle between the d-axis and the α-axis.

[0023] Furthermore, in step S3, the expression of the mathematical model in the simplified two-phase rotating dq coordinate system is:

[0024]

[0025] in:

[0026]

[0027] The present invention also provides a control method for a Vienna rectifier under unbalanced inductance, and the Vienna rectifier is controlled based on the above-mentioned modeling method, comprising the following steps:

[0028] S4: Voltage outer loop control

[0029] The output voltage signal U of the Vienna rectifier under inductance imbalance is obtained by sampling dc , the output voltage reference value The sampled output voltage signal U dc Compare and make difference to get the output voltage signal U dc The error between the voltage and the reference value is sent to the voltage outer loop proportional-integral regulator, and the voltage outer loop control of the Vienna rectifier under inductance imbalance is established. The output value of the voltage outer loop is sent to the current inner loop as the current reference value of the d-axis of the current inner loop.

[0030] S5: Current inner loop control

[0031] According to the simplified mathematical model of two-phase rotating dq coordinate system, we can get U d , U q The calculation expression of U d , U q The calculation expression of is designed to obtain the current inner loop control model; the input voltage of each phase of Vienna rectifier is sampled e a 、e b 、e c , each phase input current i a 、i b 、i c , perform coordinate transformation to obtain the d-axis and q-axis input voltages e of the Vienna rectifier under inductance imbalance d 、e q And the d-axis and q-axis input current i d 、i q ; Set the current reference value of the current inner loop d axis Current reference value of q axis and d-axis input current i d , q-axis input current i d By comparing and making the difference, the d-axis and q-axis current errors are obtained respectively, and the current errors are respectively sent to the current inner loop proportional-integral regulator, and the output U of the current inner loop is obtained according to the current inner loop control model. d (s), U q (s), forming the current inner loop control of the Vienna rectifier under inductance imbalance; the output U d (s), U q(s) is sent to the switch tube modulation strategy, which adopts a carrier-based pulse width modulation strategy to realize the control of the Vienna rectifier under inductance imbalance.

[0032] Furthermore, in step S5, U d , U q The calculation expression is as follows:

[0033]

[0034] Furthermore, in step S5, according to U d , U q The calculation expression of the current inner loop control model is designed as follows:

[0035]

[0036] Among them, s is the Laplace operator; U d (s), U q (s) is the Laplace transform of the d-axis and q-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point of the AC side in the two-phase rotating dq coordinate system; e d (s), e q (s) is the pull-type transformation of the d-axis and q-axis input voltages of the Vienna rectifier in the two-phase rotating dq coordinate system; K p , K i are the proportional control coefficient and integral control coefficient of the current loop; is the current loop d-axis current reference value and q-axis current reference value; i d (s), i q (s) is the Laplace transform of the d-axis and q-axis input currents of the Vienna rectifier in the two-phase rotating dq coordinate system.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] Compared with the traditional dual closed-loop control method, the influence of unbalanced inductance is considered when mathematically modeling the Vienna rectifier, and the three-phase unbalanced inductance information is introduced into the control method to suppress the AC side current distortion problem caused by the unbalanced three-phase inductance. The control effect of the present invention under the three-phase inductance balanced state is consistent with the conventional dual closed-loop control effect. When the inductance of a certain phase changes greatly, it can still maintain a good AC side current quality, so that the rectifier has better stability, does not need to perform detailed adjustment of the controller parameters of the current loop, and can cope with more complex working conditions in production. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 1 is a topological diagram of a Vienna rectifier under unbalanced inductance in the first embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the control method in Embodiment 1 of the present invention;

[0041] Figure 3 This is a simulation waveform diagram of the rectifier input current using a conventional voltage-current dual closed-loop control method under inductance imbalance in the second embodiment of the present invention;

[0042] Figure 4 This is a diagram showing the FFT analysis result of the rectifier A-phase input current using a conventional voltage-current dual closed-loop control method under inductance imbalance in the second embodiment of the present invention;

[0043] Figure 5 This is a diagram showing the FFT analysis result of the rectifier B phase input current using a conventional voltage and current dual closed-loop control method under inductance imbalance in the second embodiment of the present invention;

[0044] Figure 6 This is a diagram showing the FFT analysis results of the rectifier C-phase input current using a conventional voltage-current dual closed-loop control method under inductance imbalance in the second embodiment of the present invention;

[0045] Figure 7 This is a simulated waveform diagram of the input current of the rectifier using the control method proposed by the present invention under the condition of inductance imbalance in the second embodiment of the present invention;

[0046] Figure 8 This is a diagram showing the FFT analysis result of the A-phase input current of the rectifier using the control method proposed by the present invention under the condition of inductance imbalance in the second embodiment of the present invention;

[0047] Fig. 9 This is a diagram showing the FFT analysis result of the B-phase input current of the rectifier using the control method proposed by the present invention under inductance imbalance in the second embodiment of the present invention;

[0048] Fig.10 This is a diagram showing the FFT analysis results of the C-phase input current of the rectifier using the control method proposed by the present invention under inductance imbalance in the second embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0050] Embodiment 1

[0051] like Figure 1 As shown in FIG. 1 , it is a topological diagram of the Vienna rectifier under the unbalanced inductance condition used in this embodiment, where e a 、e b 、ec is the input voltage of each phase, L a , L b , L c is the inductance of each phase on the AC side, D 1 ~D 6 is a diode, S 1 ~S 6 For the switch tube, C 1 , C 2 is the output capacitor, and R is the DC side load resistance.

[0052] like Figure 2 As shown, this embodiment provides a modeling and control method for a Vienna rectifier under unbalanced inductance, which specifically includes the following steps:

[0053] Step 1: Establish the mathematical model of the three-phase static abc coordinate system of the Vienna rectifier AC side, and its expression is:

[0054]

[0055] Among them, L a , L b , L c is the inductance of each phase on the AC side of Vienna rectifier; e a 、e b 、e c is the input voltage of each phase of Vienna rectifier in the three-phase stationary abc coordinate system; i a 、i b 、i c is the input current of each phase of Vienna rectifier in the three-phase stationary abc coordinate system; is the differential of each phase input current with respect to time; U aN , U bN , U cN is the voltage of the diode clamping point at each phase input end of the Vienna rectifier relative to the neutral point on the AC side in the three-phase stationary abc coordinate system; R is the load resistance on the DC side.

[0056] Step 2: Use Clarke transformation to transform the mathematical model of the three-phase static abc coordinate system of the Vienna rectifier AC side into the mathematical model of the two-phase static αβ coordinate system. The expression is:

[0057]

[0058] in:

[0059]

[0060] Among them, e α 、e βis the input voltage of the α-axis and β-axis of the Vienna rectifier in the two-phase stationary αβ coordinate system; i α 、i β is the input current of the α-axis and β-axis of the Vienna rectifier in the two-phase stationary αβ coordinate system; is the differential of the input current of the α-axis and β-axis with respect to time; U α , U β are the α-axis and β-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point on the AC side in the two-phase stationary αβ coordinate system.

[0061] Step 3: Use Park transformation to transform the mathematical model in the two-phase stationary αβ coordinate system into the mathematical model in the two-phase rotating dq coordinate system. The expression is:

[0062]

[0063] in:

[0064]

[0065] Among them, e d 、e q is the input voltage of the Vienna rectifier on the d-axis and q-axis in the two-phase rotating dq coordinate system; i d 、i q is the input current of the Vienna rectifier on the d-axis and q-axis in the two-phase rotating dq coordinate system; is the differential of the d-axis and q-axis input current with respect to time; U d , U q are the d-axis and q-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point of the AC side in the two-phase rotating dq coordinate system; ω is the angular frequency of the industrial frequency AC power, and θ is the angle between the d-axis and the α-axis.

[0066] Step 4: Simplify the mathematical model in the two-phase rotating dq coordinate system to obtain a simplified mathematical model in the two-phase rotating dq coordinate system, and its expression is:

[0067]

[0068] in:

[0069]

[0070] When L a , L b , L c When the inductance values ​​are equal, it is the traditional Vienna rectifier mathematical model.

[0071] Step 5: According to the simplified mathematical model of the two-phase rotating dq coordinate system, we can obtain Ud , U q The calculation expression is:

[0072]

[0073] Step 6: According to U d , U q The calculation expression of is designed to obtain the current inner loop control model, and its expression is:

[0074]

[0075] Among them, s is the Laplace operator; U d (s), U q (s) is the Laplace transform of the d-axis and q-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point of the AC side in the two-phase rotating dq coordinate system; e d (s), e q (s) is the pull-type transformation of the d-axis and q-axis input voltages of the Vienna rectifier in the two-phase rotating dq coordinate system; is the current reference value of the d-axis and q-axis current of the current loop; i d (s), i q (s) is the Laplace transform of the d-axis and q-axis input current of the Vienna rectifier in the two-phase rotating dq coordinate system; K p , K i are the proportional control coefficient and integral control coefficient of the current loop.

[0076] Step 7: Sample and obtain the output voltage signal U of the Vienna rectifier under inductance imbalance dc , each phase input voltage e a 、e b 、e c , each phase input current i a 、i b 、i c .

[0077] Step 8: Set the output voltage reference value The sampled output voltage signal U dc Compare and make difference to get the output voltage signal U dc The error between the voltage and the reference value is sent to the voltage outer loop proportional-integral regulator to form the voltage outer loop control of the Vienna rectifier under inductance imbalance. The output value of the voltage outer loop is sent to the current inner loop as the current reference value of the d-axis of the current inner loop.

[0078] Step 9: Input voltage e for each phase a 、e b 、e cAnd each phase input current i a 、i b 、i c Perform coordinate transformation to obtain the d-axis and q-axis input voltages e of the Vienna rectifier under inductance imbalance d 、e q And the d-axis and q-axis input current i d 、i q , the current reference value of the current inner loop d axis Current reference value of q axis and d-axis input current i d , q-axis input current i d By comparing and making the difference, we can get the d-axis and q-axis current errors respectively, and send the current errors to the current inner loop proportional-integral regulator respectively. According to the current inner loop control model, we can get the output U of the current inner loop. d (s), U q (s), forming the current inner loop control of the Vienna rectifier under inductance imbalance.

[0079] Step 10: The output U of the inner current loop d (s), U q (s) The modulation strategy sent to the switch tube adopts a carrier-based pulse width modulation strategy to achieve control of the Vienna rectifier under inductance imbalance.

[0080] Embodiment 2

[0081] In this embodiment, the Vienna rectifier control method under unbalanced inductance in the first embodiment is used to build a simulation study in matlab / simulink to verify the feasibility of the present invention.

[0082] Set the three-phase input line voltage to 380V, the input voltage frequency to 50Hz, the output voltage to 750V, the output power to 15kW, the sampling frequency to 30kHz, and the inductance of each phase on the AC side to L a , L b , L c It is divided into 0.8mH, 1.0mH, 1.4mH, output capacitance C 1 , C 2 Both are 1100μF;

[0083] Vienna rectifier adopts conventional voltage and current double closed loop control under inductance imbalance. Figure 3 , Figure 4 , Figure 5 , Figure 6It can be seen that the total harmonic distortion (THD) of the A-phase input current is 7.60%, the total harmonic distortion (THD) of the B-phase input current is 6.93%, and the total harmonic distortion (THD) of the C-phase input current is 3.47%. The input current has a relatively high harmonic content.

[0084] The control method of the Vienna rectifier under inductance imbalance proposed in the first embodiment is adopted. Figure 7 , Figure 8 , Fig. 9 , Fig.10 It can be seen that when the inductance of the Vienna rectifier is unbalanced and the inductance of a certain phase changes greatly, the input current harmonic content is less, the total harmonic distortion rate (THD) of the A-phase input current is 4.72%, the total harmonic distortion rate (THD) of the B-phase input current is 4.08%, and the total harmonic distortion rate (THD) of the C-phase input current is 2.92%. Compared with the conventional voltage and current dual closed-loop control, the total harmonic distortion rate of the input current is reduced, and the AC side can maintain better current quality.

[0085] From the comparison of simulation results, it can be seen that under the condition of unbalanced inductance, the control method used in the present invention can maintain good quality of AC side current when the inductance drop of a certain phase is large, and the Vienna rectifier has good stability.

[0086] In summary, the modeling and control method of the Vienna rectifier under unbalanced inductance in the above-mentioned embodiment, compared with the traditional dual closed-loop control method, considers the influence of unbalanced inductance when mathematically modeling the Vienna rectifier, introduces the three-phase unbalanced inductance information into the control method, and suppresses the AC side current distortion problem caused by the three-phase inductance imbalance; the control effect of the present invention under the three-phase inductance balanced state is consistent with the conventional dual closed-loop control effect, and can still maintain good AC side current quality when the inductance of a certain phase changes greatly, so that the rectifier has better stability, does not need to perform detailed adjustment of the controller parameters of the current loop, and can cope with more complex working conditions in production.

[0087] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A modeling method for Vienna rectifier under inductance imbalance, characterized in that: The following steps are involved: S1: Establish the mathematical model of the three-phase static abc coordinate system of the Vienna rectifier AC side; S2: Using Clarke transformation, the mathematical model of the three-phase static abc coordinate system of the AC side of the Vienna rectifier is transformed into a mathematical model of the two-phase static αβ coordinate system; S3: Using Park transformation, the mathematical model in the two-phase stationary αβ coordinate system is converted into a mathematical model in the two-phase rotating dq coordinate system and simplified to obtain a simplified mathematical model in the two-phase rotating dq coordinate system.

2. The modeling method of a Vienna rectifier under unbalanced inductance according to claim 1, characterized in that: In step S1, the mathematical model of the three-phase stationary abc coordinate system of the Vienna rectifier AC side is established as follows: Among them, L a , L b , L c is the inductance of each phase on the AC side of Vienna rectifier; e a 、e b 、e c is the input voltage of each phase of Vienna rectifier in the three-phase stationary abc coordinate system; i a 、i b 、i c is the input current of each phase of Vienna rectifier in the three-phase stationary abc coordinate system; is the differential of each phase input current with respect to time; U aN , U bN , U cN is the voltage of the diode clamping point at each phase input end of the Vienna rectifier relative to the neutral point on the AC side in the three-phase stationary abc coordinate system; R is the load resistance on the DC side.

3. The modeling method of a Vienna rectifier under inductance imbalance according to claim 1 is characterized in that: In step S2, the expression of the mathematical model in the two-phase stationary αβ coordinate system is converted as follows: in: Among them, e α 、e β is the input voltage of the α-axis and β-axis of the Vienna rectifier in the two-phase stationary αβ coordinate system; i α 、i β is the input current of the α-axis and β-axis of the Vienna rectifier in the two-phase stationary αβ coordinate system; is the differential of the input current of the α-axis and β-axis with respect to time; U α , U β are the α-axis and β-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point on the AC side in the two-phase stationary αβ coordinate system.

4. The modeling method of a Vienna rectifier under unbalanced inductance according to claim 1, characterized in that: In step S3, the expression of the mathematical model in the two-phase rotating dq coordinate system is: in: Among them, e d 、e q is the input voltage of the Vienna rectifier on the d-axis and q-axis in the two-phase rotating dq coordinate system; i d 、i q is the input current of the Vienna rectifier on the d-axis and q-axis in the two-phase rotating dq coordinate system; is the differential of the d-axis and q-axis input current with respect to time; U d , U q are the d-axis and q-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point of the AC side in the two-phase rotating dq coordinate system; ω is the angular frequency of the industrial frequency AC power, and θ is the angle between the d-axis and the α-axis.

5. The modeling method of a Vienna rectifier under unbalanced inductance according to claim 1, characterized in that: In step S3, the expression of the mathematical model in the simplified two-phase rotating dq coordinate system is: in:

6. A control method for a Vienna rectifier under inductance imbalance, characterized in that: Controlling the Vienna rectifier based on the modeling method according to any one of claims 1 to 5 comprises the following steps: S4: Voltage outer loop control The output voltage signal U of the Vienna rectifier under inductance imbalance is obtained by sampling dc , the output voltage reference value The sampled output voltage signal U dc Compare and make difference to get the output voltage signal U dc The error between the voltage and the reference value is sent to the voltage outer loop proportional-integral regulator, and the voltage outer loop control of the Vienna rectifier under inductance imbalance is established. The output value of the voltage outer loop is sent to the current inner loop as the current reference value of the d-axis of the current inner loop. S5: Current inner loop control According to the simplified mathematical model of two-phase rotating dq coordinate system, we can get U d , U q The calculation expression of U d , U q The calculation expression of is designed to obtain the current inner loop control model; the input voltage of each phase of Vienna rectifier is sampled e a 、e b 、e c , each phase input current i a 、i b 、i c , perform coordinate transformation to obtain the d-axis and q-axis input voltages e of the Vienna rectifier under inductance imbalance d 、e q And the d-axis and q-axis input current i d 、i q ; Set the current reference value of the current inner loop d axis Current reference value of q axis and d-axis input current i d , q-axis input current i d By comparing and making the difference, the d-axis and q-axis current errors are obtained respectively, and the current errors are respectively sent to the current inner loop proportional-integral regulator, and the output U of the current inner loop is obtained according to the current inner loop control model. d (s), U q (s), forming the current inner loop control of the Vienna rectifier under inductance imbalance; the output U d (s), U q (s) is sent to the switch tube modulation strategy, which adopts a carrier-based pulse width modulation strategy to realize the control of the Vienna rectifier under inductance imbalance.

7. The control method of a Vienna rectifier under inductance imbalance according to claim 6, characterized in that: In step S5, U d , U q The calculation expression is as follows:

8. The control method of a Vienna rectifier under unbalanced inductance according to claim 7, characterized in that: In step S5, according to U d , U q The calculation expression of the current inner loop control model is designed as follows: Among them, s is the Laplace operator; U d (s), U q (s) is the Laplace transform of the d-axis and q-axis voltages of the diode clamping point at the input end of the Vienna rectifier relative to the neutral point of the AC side in the two-phase rotating dq coordinate system; e d (s), e q (s) is the pull-type transformation of the d-axis and q-axis input voltages of the Vienna rectifier in the two-phase rotating dq coordinate system; K p , K i are the proportional control coefficient and integral control coefficient of the current loop; is the current loop d-axis current reference value and q-axis current reference value; i d (s), i q (s) is the Laplace transform of the d-axis and q-axis input currents of the Vienna rectifier in the two-phase rotating dq coordinate system.

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