Voltage-controlled half-bridge neutral-point diode-clamped rectifier without current sensor

A voltage-controlled neutral-point diode-clamped rectifier is proposed to achieve high power factor, low current distortion and constant dc bus voltage. The voltage stress of each power semiconductor of the adopted rectifier is equal to half dc bus voltage instead of full dc link voltage in the conventional switching mode rectifier. A voltage control scheme without current sensor is employed to track the line current command. The control signals of the power switches are derived from the dc link voltage controller and neutral point voltage compensator. A carrier-based PWM scheme is employed to draw a clean sinusoidal line current, high input power factor, regulated dc link voltage and balance capacitor voltages. Three voltage levels are generated on the ac terminal of the adopted rectifier. To verify the proposed operation scheme, performance characteristics are given by the simulation and experimental results.