Showing papers by "V. Fernao Pires published in 2001"

Single-phase unity power-factor double buck rectifier: topology, operation and control

Abstract: This paper presents a new single-phase high power factor double buck rectifier. Unlike the buck rectifier, in which the output voltage is always smaller than the maximum input voltage, the proposed converter can operate with higher output voltages. The converter topology and operation are presented. A sliding mode control of the input current, capable of fast and robust current control, is also proposed. Using this control method, the converter presents high power factor and draws nearly sinusoidal input currents. A proportional integral (PI) controller is used to regulate the output voltage of the converter. This external voltage controller modulates the amplitude of the input current reference. Experimental results from a laboratory prototype are presented and discussed.

Three-phase single-stage step-up/down current rectifiers with sliding mode PWM current controller and low sensitivity voltage regulator

Abstract: This paper presents an active sliding mode PWM current controller for three-phase single-stage step-up/down current rectifiers operating in continuous current mode. This current controller imposes the input line currents to track the desired suitable sinusoidal signal in phase with the input source voltages, ensuring a near unity power factor operation of the rectifier. With this control strategy, the input currents are actively shaped, being possible to maintain a near sinusoidal current even with high ripple DC inductor current. A low sensitivity output voltage regulator modulating the sinusoidal reference amplitude of the current controller is also proposed. Experimental results are presented, and the performance compared with the behaviour of the conventional proportional integral output voltage control.