Pages: 30-34

Abstract

ABSTRACT: This paper presents a Z-source inverter for controlling the speed and reducing the torque ripple of a brushless DC motor. This inverter uses a unique impedance network, coupled between a power source and the inverter circuit, to provide both boost and buck-boost inverters properties, which cannot be achieved by conventional voltage source and current source inverters. The PI controller has been used as a closed loop controller, which improves the speed control of the brushless DC motor for any load. The hysteresis controller has been implemented to control the motor output current and provide suitable switching system for Z-source inverter. As a result, the new Z-source inverter by self boosting brings the output voltage higher value as in a six-switches standard three-phase inverter. Therefore, it expands the motor operating speed range and reduces its torque ripple. Analysis and simulation results are presented in result section to demonstrate these new features.