A New Three-Phase Rectifier for Regenerative Braking Application

This paper proposes a new regenerative rectifier for motor loads. The controller is implemented with simple analog components. Yet, it has the power of controlling a three-phase Voltage Source Inverter to operate either as a Power Factor Correction rectifier or as a Grid Connected Inverter according to motor´s operational status. In both cases, the currents are sinusoidal. A 5 KW simulation model and a 350 W experimental prototype were built to verify the concept. It is proven both in simulation and experiment that the proposed regenerative rectifier is capable of performing front-end power processing for a motor regardless of its operational status. The control is realized through the injection of three phase reference voltage signals, whose amplitude is adjusted according to motor´s power level and operational status. At the motor´s normal operational status, the amplitude of injected reference voltage signals are adjusted to be low and the measured phase currents are sinusoidal and in phase with the phase voltages. During braking, the amplitude of injected voltage signals are tuned high so that the energy from the motor is recycled back to the grid with sinusoidal and 180deg out of phase waveforms that marks the significance of regenerative braking (inverter) technology. DC bus voltage remains constant in both situations. Due to its high performance as well as prominent simplicity and reliability, the proposed regenerative rectifier provides an excellent solution for motor drives.