Study And Design On PV Array Emulator

In the 21^st century, mankind is facing with the serious challenges of sustainable economic and social development. While issue of energy is increasingly prominent, solar and other renewable energy has gradually become the focus of attention. Today, human study on PV systems is more and more extensive. Because of the influence of the sunlight intensity and surroundings temperature, the cost of PV array experiments is too high and the cycle of study becomes too long. PV array emulator can solve this problem.In this paper, the advantages and disadvantages between analog PV array emulator and digital PV array emulator are compared. Digital PV array emulator is selected in this paper for study. This paper illustrates the practical significance of studying PV array emulator. Then, it describes the I-V output characteristics of PV cell and discusses the mathematical model suitable for engineering calculations.The PV array emulator designed in this paper is constituted by two parts--main circuit and control circuit. Half-bridge DC/DC circuit is selected as the main circuit topology. Its working process is analyzed in detail. Then this paper designs the main circuit and the voltage- current double closed-loop regulator. On this base, by simulating the PV array emulator in PSIM platform, we can conclude that various performance parameters can meet the requirements.The Control circuit board is the core controller of the PV array emulator. It can provide the reference value of output voltage and the PWM signals for controlling power tube. In this paper, microchip's dsPIC30F2023 is selected as the main control chip. This paper analyzes the performance and characteristics of this chip. Then it introduces hardware design of peripheral circuits such as analog signal sampling circuit, communication circuit RS232, human-computer interface circuit etc. Regulator adopts digital PID control.This paper also gives related software design in MPLAB integrated development environment. Besides, it also introduces program flow of each module. It mainly contains main program, PWM generating program, AD sampling program, fault handling program, human-computer interaction program etc.Upon completion of the software and hardware design, the PV array emulator has been achieved. It can provide a good experimental platform for the study of PV systems.