Z-Source Inverter for Fuel Cell application

Abstract

The thesis presents the analysis of a single phase and three phase Z-source inverter used for fuel cell applications and its control methods for implementation in dc-to-ac power conversion system is presented. This thesis brings together the problems in the use of fuel cell as a power source. The basic problem is with the fuel cell is that it give a fixed DC output. So this can’t be used for various function like in HEV or other applications. So to overcome this problem Z-source is connected to the full cell. The design of Z-network, single phase and three phase full bridge inverter mathematical modelingis done .The simulation work is carried in MATLAB-Simulink.A fixed DC input voltage (V) is applied across the inverter and a controlled AC output voltage (V) is obtained by varying the duty cycle of the inverter. The duty cycle variation is be achieved by using pulse Width modulation (PWM) control methods. In control strategies Sinusoidal carrier-based PWM and Simple Boost Control method is used. These methods are described in detail and simulation work is presented in support of that. The output voltage and current ripples are controlled by varying the modulation index and switching frequency. The effect of shoot through state on the traditional inverter is eliminated in the Z-source inverter. The traditional inverters can be used either as buck or boost converter.This limitation is sorted by the use Z-source inverter.Z-source buck-boost capabilities are verified analytically and simulation results are presented. Different applications are presented for the verification of the modeling and simulated system along with two control strategies.One of the strategies is based on performance and simulation analysis of fuel cell (FC) system. Second application is based on modeling and simulation of Z-source inverter for single phase and three phases to control the speed of Induction Motor.