No abstract

This study describes a novel method in improving the input current total harmonic distortion as well as power factor of a three-phase diode rectifier circuit. In this method, three bidirectional switches comprising MOSFET and four diodes are used across the three-phase supply and load. In a three-phase rectifier only two diodes conduct at any given time. As a result, the current in the third phase is zero. But in this method, the bidirectional switch corresponding to the third phase is turned ON. The closing of bidirectional switches provides an alternate path for the input current to flow. Once the input voltage crosses zero-voltage axes, the corresponding switch will be triggered. The fuzzy logic based control method is used to generate the triggering pulse for the bidirectional switches. The conduction angle of bidirectional switch is adjusted to make the output power constant and at the rated value for converter operation above and below its rated power. The performances of DC motor drive as well as Induction motor drive are evaluated with this method. The analysis, simulation and experimental results of three phase rectifier are also presented in this study.