Design and Fabrication of Novel Three-Phase Front-End Converter with Unity Power Factor

Abstract

In recent years, an increasing portion of generated electrical energy is converted through rectifier, before it is used at the final load. A three-phase AC to DC converter is an essential part of many power electronic systems such as Un-interruptible Power Supplies (UPS), battery chargers and motor drives. The battery charger needs AC to DC conversion, while UPS and motor drives typically have an AC to DC conversion stage followed by DC to AC conversion.

The rectifier act as non-linear load on the power system which causes low input power factor and injects harmonics into the AC system. The harmonic content and low power factor at the supply side due to rectifier has been of great concern. These drawbacks can cause various undesirable effects, such as harmonic distortion of line voltage, equipment overheating, malfunction, and damage.

In order to mitigate these problems many new techniques have been proposed to improve the input power factor and reduce current harmonics for three-phase diode rectifiers. Various three-phase high power factor converters and also current control schemes for low current distortion and unity power factor are studied. Among the current controlled PWM converters, the hysteresis controller based converters are extensively used due to their simplicity and fast dynamic response.

Simulation and fabrication of hysteresis current controller has been carried out. As a result of the work, unity power factor and Low %THD of input current is achieved by simulation under steady state and transient conditions, as well as for different values of input inductance.