Carrier Based PWM for Reduced Capacitor Voltage Ripple in Three-Phase Three-Switch Buck-Type Rectifier System

This paper investigates an economic and highly efficient power converter topology and its modulation scheme for 60kW buck-type rectifier system. The target system consists of three-phase three-switch buck-type rectifier topology. A new Carrier Based PWM scheme along with its simple implementation using logic gates is introduced. This PWM scheme replaces the diode rectifier equivalent switching state with an active switching state producing the effectively same current flowing path as a reference command of converter input current. As a result, the distortion of input current during the polarity reversal of capacitor line voltage can be mitigated. In this paper, the characteristics of the PWM methods are analyzed and compared based on two criteria such as the capacitor voltages and grid currents distortion. The proposed modulation technique is also confirmed through simulation and HILS verification.