Analysis And Research On Single-phase Grid-Connected Photovoltaic System

Solar energy is a new energy which is effective, non-polluting for sustainable development. It has been received extensive attention around world. Photovoltaic power generation is an important aspect of solar energy utilization, and the photovoltaic grid-connected is inevitable direction of the large scale photovoltaic power generation. The grid-connected inverter is the core components of grid-connected PV generation system.(GCPS).This paper takes much effort in the control algorithm research, simulation, and hardware and software design of the single-phase photovoltaic grid-connected inverter.This paper analyzed the topology of GCPS. Through the compare of used current tracking strategies, this paper makes in-depth study on deadbeat PWM control method. To solve the effect of the delay, a deadbeat control algorithm is presented. Appropriate method was used to predict state parameter.This method improved the quality of grid-connected current. This algorithm is simulated and compared with SPWM control. The result of simulation indicates this deadbeat control algorithm is superior to traditional SPWM control.This paper takes much effort in the MPPT (Maximum power point tracking) method of single-stage GCPS which is more efficient. Through compare and analyzed of used MPPT method, A MPPT method based on gradient is proposed. And this paper improved gradient method on stability. This paper from another point of view, according to the structure and control characteristics of the single-stage photovoltaic power system, use fuzzy self-adaptive PID control to regulate voltage of PV array. Simulations results show that, this structure can make the voltage loop have a high quality dynamic and static response. And this structure which is robust, further enhance the responsiveness and tracking precision of the MPPT.This paper researches the GCPS which with reactive power and active filter. Comprehend and absorb the instantaneous reactive power theory. Select right harmonic and reactive power current detection algorithm. Combine the MPPT and current compensation control, so that the GCPS also can compensation the reactive power and harmonic in the grid. This paper use the MATLAB to verify the control theory, and research the affects which made by the compensation control to the MPPT control.At last, this paper researches the hardware and software design of GCPS. This paper carries out the details in the hardware topology, the control board design, the main power items calculation. And also discuss the DPLL and PWM generation method .Finally, the full work of the paper was summarized and research content on this subject in the future was made predicted.