An advanced controller to improve the power quality of microgrid connected converter

Abstract

This paper presents a new controller of a microgrid connected converter to reduce harmonic components to ensure high quality of electrical power, although the microgrid connected inverter with an LCL filter has the ability of attenuating the higher order harmonics. The major advantage of the proposed controller is that it can attenuate both the higher and lower order harmonics with a small size line filter which minimize both the physical size and cost of the system. Fast Fourier transform (FFT) and total harmonic distortion (THD) of the output voltage waveform is measured and compared to the preset tolerance level. The controller uses new type of modulation by using feed-forward control instead of feedback control to obtain quick response. Comparison of different output waveforms of converter using different modulation like space vector modulation (SVM), advanced pulse width modulation (PWM) and the proposed modulation are presented. The proposed controller using feed-forward scheme can effectively suppress the distortion arises from the grid voltage harmonics as well as regulate for different load conditions and power generation. MATLAB/Simulink is used for simulation of the entire system.