Design And Implementation Of Current-Source PV Grid-Connected Inverter Control System

The paper focuses on the algorithm of control current-source PV grid-connected inverter and designs the control system. The goal this paper will get is changing PV DC power to three-phase that grid synchronization, at the same time controlling the grid-connected current has a same phase with grid voltage. In the beginning of this design, paper uses analog modulation to prove the correction of control system. In control the object, this paper uses direct current control in control way, and the control mode is based on the traditional three-logic SPWM, quotes and analyses a new mode, use carrier folds SPWM control named it in this paper.The first work is using Matlab/simulink simulates three-phase current-source PV grid-connected inverter main circuit and control circuit, including the traditional SPWM mode, the carrier folds SPWM mode, the MPPT and PLL control algorithm. Then compare the two different modes’ performance and grid-connected currents’ harmonic. Matlab/simulink simulation verifies the control algorithm is feasible and low loss. The second work is implementing at control system of current-source PV grid-connected inverter. This paper designs the control system from two sides. Hardware will use dsPIC30F6010A chip which is produced by Microchip in implementation of system algorithm aspect. Because of the system requirements, this paper designs DC voltage and current acquisition circuits, AC current acquisition circuits, zero detection circuit, minimum system and DAC circuit. In order to validate simulation modulation, designs simulation modulation driver circuit and voltage transformation circuit. On the software side, this paper writes C code for analog modulation and logical modulation under MPLAB IDE, and gives the routine flowchart of main program and interrupts service, and then compiles C code and downloads the program after debug in MPLAB IDE. Finally, in laboratory environment using simulation modulation reaches the change PV DC output to asynchronous motor AC input. And through the data collected in the object and the running status of the system verify the control system under the digital modulation is reasonable and practical.