Research On Islanding Detection Methods Of Single-phase Grid Connected Photovoltaic Inverter

With the development of industry, energy and environment problem can not be avoided. Green energy technologies have become the focus of research in each country, photovoltaic power generation as an important way to use solar energy has become hot research direction of green energy technologies. Islanding detection as a necessity of PV inverters also becomes important research direction. This paper focuses on research of islanding detection basing on a non-isolated single-phase inverter.This paper describes the significance and background of islanding detection. After reviewing the existing testing standards, assessment methods and detecting methods, this paper selects detecting methods which base on the frequency shift, phase shift and power disturbance as the focal point. The Non-detection Zone(DNZ) of detecting methods is analyzed in Qf0×Cnorm coordinate system, and verify results by simulation. In addition, determine a non-transformer and two-level topology by analyzing the work principle and the topology structure of photovoltaic power system. Use the H-bridge topology as the inverter part, and use voltage and current closed-loop SPWM control mode. Through modeling and simulation to verify the control algorithm can be realized.This paper completes the design of main power circuit, driver circuit, sampling circuit, power supply circuit, and finishes the key program according to the analyzing of overall system and simulation. Conducted experiments on the prototype, Analysis efficiency of the prototype under each power condition, and record the harmonic distortion of the output current. Finally this paper finishes the experiment on the prototype, according to the test standards.