Research on Two-Stage Three-Phase Photovoltaic Grid-Connected System

2012 ◽  
Vol 535-537 ◽  
pp. 1247-1251
Author(s):  
Xiao Jie Zhou ◽  
Yi Ruan

Nowadays the penetration of PV-generated power energy into the utility grid is increasing exponentially. This paper focuses on two-stage three-phase grid-connected PV systems, which includes modeling of three-phase grid-connected PV systems, grid-connected control strategy of inverter. The inverter based on the grid-voltage oriented vector control used SVPWM-based synchronous current vector PI controllers to control the grid-current of the common point in three-phase grid-connected system. Theoretic analysis and experimental results on a 2.5KW prototype verify the presented algorithm.

2017 ◽  
Vol 32 (11) ◽  
pp. 8559-8569 ◽  
Author(s):  
Ariya Sangwongwanich ◽  
Yongheng Yang ◽  
Frede Blaabjerg

Vestnik MEI ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 51-59
Author(s):  
Vladimir M. Tereshkin ◽  
◽  
Irshat L. Aitov ◽  
Dmitriy A. Grishin ◽  
Vyacheslav V. Tereshkin ◽  
...  

The aim of the study is to determine the parameters characterizing the ripple of a motor's three- and five-phase windings common point potentials (for the star winding connection diagram) with respect to the converter zero point. One of the reserves for decreasing electromagnetically induced vibration of an electric motor with a rotating field is to increase the number of working winding phases. The study subject is a five-phase motor winding connected to a bridge converter, namely, its ability to reduce electromagnetically induced vibration in comparison with that in using a three-phase winding. The common point potential ripple parameters are studied, and an approach is proposed to estimating the amplitude modulation of the space-time voltage vector of three- and five-phase windings under the influence of the common point potential ripple with respect to the converter zero point. Theoretical studies were carried out using the Fourier series expansion method and vector analysis methods. To confirm the theoretical results, experimental studies of the prototypes of three-phase and five-phase synchronous motors with inductors made on the basis of permanent magnets were carried out. The main results have shown the following. With increasing the number of phases of the rotating field motor working winding connected to a bridge converter, the common point potential ripple amplitude with respect to the converter zero point decreases, and the ripple frequency increases. The product of ripple amplitude by frequency remains unchanged. It is assumed that the common point potential ripple of the motor multiphase winding with respect to the converter zero terminal results in the amplitude modulation of the space-time voltage vector. With increasing the number of winding phases, the modulation amplitude decreases, and the modulation frequency increases. A five-phase motor has a lower level of the working winding common point potential ripple with respect to the converter zero point in comparison with a three-phase motor. Thus, it can be assumed that there will be a lower level of electromagnetically induced vibration in using a simple converter operation algorithm. The obtained results can be used in designing electric traction systems with vector control on the basis of multiphase motors. With increasing the number of phases, the common point potential ripple amplitude in a multiphase winding with respect to the converter zero point decreases, and the ripple frequency increases. Thus, the common point potential ripple amplitude in a five-phase winding is 5/3 times less than that in a three-phase winding, and the ripple frequency increases by 5/3 times, respectively. With increasing the number of working winding phases, the amplitude modulation of the resulting space-time voltage vector decreases. This circumstance has a positive effect on decreasing the electromagnetically induced vibration.


2015 ◽  
Vol 18 (3) ◽  
pp. 192-198
Author(s):  
Huy Minh Nguyen ◽  
Phuong Minh Le ◽  
Phuong Thanh Ho

This paper presents the control model of three phase grid- connected photovoltaic inverter based on the analysis of operating principle of two-stage conventional gridconnected inverter. The mathematical model of inverter under dq frame is set up and the overall control strategy of two-stage photovoltaic grid-connected inverter is proposed in this paper. To overcome the distortion general caused by switching effect on sensors, a Kalman filter is introduced. The control strategy was simulated on Matlab – Simulink to verify the steady and dynamic of model, improving the quality of electrical power to consumers.


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