The PMSG based Wind Energy Conversion System with CUK Converter and CHB MLI with a Single DC Input

Abstract

Wind power is intermittent and hence the electrical output from the wind energy conversion system varies. Therefore, it is necessary to make the output voltage of the wind energy system constant so that it can be connected to the grid. This paper presents a permanent magnet synchronous generator (PMSG) based wind energy conversion system with CUK converter in closed loop and a new topology of cascaded H-bridge multilevel inverter. The paper presents the design of the CUK converter to step-up or step-down the DC voltage of the diode rectifier fed from the wind energy conversion system. The design of a voltage controller to maintain the DC-link voltage constant inspite of the changes in the wind generator voltage due to the changes in the wind speed is also presented in this paper. The DC-link is connected to a new topology of cascaded H-Bridge multilevel inverter. The proposed topology eliminates the requirement of separate DC sources, and requires a single DC source, irrespective of the number of levels and the number of phases. The selective harmonic elimination (SHE) technique is used to produce the switching pulses for the multilevel inverter. The entire system is simulated in the MATLAB/Simulink for varying wind speeds. The simulated waveforms of the wind speed, the PMSG voltage, the DC-link voltage and the multilevel inverter voltage are shown for varying wind speeds. The simulation results show that the output voltage of the system is maintained constant even though the wind speed is varying.