Research on Combined Control Strategy of Three-Phase Photovoltaic Grid-Connected Inverter Based on Fuzzy PI Controller

2011 ◽  
Vol 347-353 ◽  
pp. 591-600
Author(s):  
Nguyen Viet Ngu ◽  
Hong Hua Wang ◽  
Le Thi Minh Tam

The control objective of three-phase photovoltaic (PV) grid-connected inverter is to generate high quality and stable AC sinusoidal output power with the same phase angle, frequency and amplitude compatible with the grid-connected voltage. To overcome the shortcoming of the normal current PWM control method and traditional PI algorithm, this paper researches a combined control strategy of three phase PV grid-connected inverter based on fuzzy PI controller. The combined control strategy switches different PWM current control method among the hysteretic PWM, SVPWM, hysteretic current SVPWM according to the error between command current and feedback current,and the d-axis command current is output of fuzzy PI controller of DC bus voltage. The simulation model of the combined control strategy for three phase PV grid-connected inverter based on normal PI controller is built with Matlab, simulation results verified the combination control strategy based on fuzzy PI controller has excellent performances.

2012 ◽  
Vol 241-244 ◽  
pp. 636-640
Author(s):  
Wu Wu Tang ◽  
Liang Liang Chen ◽  
Hong Xu Yin ◽  
Hao Dong

This paper developed a mathematical model of three-phase PV grid-connected inverter, and studied the grid-connected current control method based on PI control in synchronous rotating reference frame. Simulation and experimental results from the prototype of 30kW three-phase PV grid-connected inverter proved the correctness and the feasibility of the control strategy, and this grid-connected inverter can operate at the unity power factor state with a nice dynamic performance, and the output current has high sinusoidal and low harmonic content as well as good symmetry.


2013 ◽  
Vol 773 ◽  
pp. 139-142
Author(s):  
Jia Guo ◽  
Zhi Gang Li ◽  
Ya Ping Cheng ◽  
Chun Yan Cui

Grid-connected inverter topologies and control methods are analyzed and compared on the basis of two non-isolated PV grid-connected inverter circuit topology as 3kVA grid connected PV systems. In this paper, the current control method, the DC bus voltage outer grid current inner loop of the dual closed-loop PI control method. Sampled signal through the system circuit for processing, resulting in a SPWM drive signal to control the conduction of the power devices off the grid current control.


2013 ◽  
Vol 732-733 ◽  
pp. 1261-1264
Author(s):  
Zhi Lei Yao ◽  
Lan Xiao ◽  
Jing Xu

An improved control strategy for three-phase grid-connected inverters with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d-and q-axes grid currents is interacted in the traditional control method, and the waveform quality of the grid current is poor. As the reference output voltage cannot directly reflect the change of the reference grid current with the traditional control strategy, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d-and q-axes grid currents in the decoupled components of the grid current controller are substituted by the d-and q-axes reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results show that the grid-connected inverter with the improved control strategy has high waveform quality of the grid current and fast dynamic response.


2014 ◽  
Vol 986-987 ◽  
pp. 1098-1102 ◽  
Author(s):  
Chang Liang Liu ◽  
Hui Chao Zhang

This paper introduces a kind of grid-connected micro-inverter system. Photovoltaic micro-inverter system is a highly nonlinear and time-varying system. Compared to traditional linear control strategy, Fuzzy Controller has better robustness and stability in the changing or non-linear application. Matlab simulation model for current tracking PV Grid-connected Micro-inverter was completed based on the Fuzzy self-tuning PI controller and the control strategy was tested on the micro-inverter prototype. The resu1ts show that this control strategy can effectively reduce the tracking error of the net current, and improve the system’s dynamic response.


2013 ◽  
Vol 415 ◽  
pp. 81-88
Author(s):  
Yang Xue ◽  
Yuan Li ◽  
Jia Dong Zhang ◽  
Jing Lin ◽  
Jun Tao Yang

The space vector pulse width modulation (SVPWM), as a new kind of vector control technique, has the advantages of high voltage utilization, less distorted output, simple control method, etc. In this paper, the control technique is applied to three-phase photovoltaic (PV) grid-connected inverter system. It uses double loop control method combined with PI control technique. The simulation model of PV grid-connected inverter system is established in Matlab/Simulink. The simulation results show that the application of SVPWM technique effectively improves the dynamic performance of PV grid inverter system and the THD of grid-connected current is low.


2021 ◽  
Vol 11 (7) ◽  
pp. 3170
Author(s):  
Yahui Li ◽  
Jing Zhang ◽  
Zhenghang Hao ◽  
Peng Tian

Aiming at the problem of power coupling and complicated decoupling in the d-q coordinate system of a three-phase grid-connected inverter, a current closed-loop control strategy based on an improved QPIR (quasi-proportional integral resonant) controller in the α-β two-phase static coordinate system is proposed. Firstly, the mathematical model of an LCL three-phase grid-connected inverter is established, and its instantaneous power calculation equation is deduced. Secondly, the frequency method is applied to compare and analyze the proportional resonant, quasi-proportional resonant, and improved current controller, and the appropriate improved controller parameters are obtained according to the traditional proportional integral controller parameter design method and the weight coefficient. Finally, the improved controller is compared with the traditional controller in the simulation model of the LCL three-phase grid-connected inverter based on active damping. The results show that the proposed improved current control strategy has good dynamic response characteristics, can realize the non-static error control of grid-connected current, and realizes the decoupling control of active power and reactive power when the load jumps. At the same time, the results also prove the superiority of the proposed control strategy and verify its effectiveness.


2012 ◽  
Vol 614-615 ◽  
pp. 1578-1582
Author(s):  
Chun Qing Qi ◽  
Yi Ruan ◽  
Feng Wen Cao

This paper proposes a control strategy,based on the grid voltage oriented vector control (VOC), which makes three-phase inverter control the active and reactive power of grid-connected inverter under the premise of the direct current control. This paper analyzes the principle of three phase photovoltaic grid connected inverter and describes the control structure of the inverter. The control strategy can overcome the deficiencies of the indirect current control scheme. This paper designs the current closed-loop control system, which not only improve the system dynamic response speed and output current waveform quality, while also reduce its sensitivity to parameter changes to improve the robustness of the system. The simulation results show the validity of control strategy proposed.


2013 ◽  
Vol 380-384 ◽  
pp. 290-293
Author(s):  
Wei Wang ◽  
Xin Chun Shi

Based on the mathematical model analysis of the three-phase voltage source PWM rectifier under abc reference frame and dq reference frame in this paper, a kind of three-phase voltage source PWM rectifier feed-forward decoupling control strategy is proposed. Dynamic response of DC bus voltage for PWM rectifier is very important, because higher response means little DC bus capacitor. An adaptive PI controller for the DC bus voltage was designed in this paper in order to improve the dynamic response. The experimental results indicate that this control method has good steady-state performance and fast dynamic response. For the reason of its simple, this control method has certain practical value.


2014 ◽  
Vol 577 ◽  
pp. 321-324
Author(s):  
Ze Long Shao ◽  
Ming Quan Shi ◽  
Zhen Feng Han ◽  
Xiao Dong Wang ◽  
Qi Min Li

This paper presents a new control method for three-phase voltage source rectifier to achieve a good system output response. The design process of fuzzy immune PI controller was described in detail. Moreover, a simulation model was built by the matlab toolbox to prove that rectifiers based on immune fuzzy PI controller have better performance in respond speed, stability and robustness ability, compared with rectifiers based on conventional PI controller.


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