Control Scheme Based on Quasi Z-Source Network for Four Switch Three Phase Brushless DC Motor

This paper proposes a novel four-switch three phase brushless dc motor control scheme based on quasi Z-source network which improves the utility ratio of DC voltage, increases the range of speed and minimizes the output torque ripple. The additionally partial circuits of quasi Z-source network and the bridge arm of four-switch inverter involves the quasi Z-source converter. During the operation of motor, shoot through states are applied. Then the input voltage of inverter extends and the performance of motor can be markedly improved. The dynamic performance of current is influenced and the speed is limited, for the irregular dc-link voltage utilization in the control of four-switch three phase Brushless DC motor. This paper presents a novel topology, which merges quasi Z-source converter and four-switch three phase drive circuit. The drawbacks of four-switch three-phase Brush less DC motor are analyzed; the control methods of each mode in quasi Z-source four-switch three phase topology are illustrated. Simulations for quasi Z-source four-switch three-phase Brushless DC motor were constructed in MATLAB/Simulink circumstance. To reduce the ripple in torque and distortion in current the quasi Z-source four-switch three-phase Brushless DC motor control scheme is proposed.