{High-precision current source using low-loss, single-switch, three-phase AC/DC converter}

Title{High-precision current source using low-loss, single-switch, three-phase AC/DC converter}
Publication TypeMiscellaneous
Year of Publication1996
AuthorsPomilio JA, Spiazzi G
ISBN Number0885-8993 VO - 11
Keywords300 Hz, 400 W, AC-DC power convertors, auxiliary circuit, constant current sources, constant duty-cycle, Control systems, DC-DC power converters, discontinuous input current mode operation, duty-cycle, electromagnet, Electromagnets, Feeds, high power factor, high-precision current source, inductance, inductive load, isolated Cuk topology, line disturbance sensitivity reduction, low-loss converter, magnetic leakage, output current, over-voltage limiting, power supplies to apparatus, power transistor, Pulse width modulation, pulse-width modulation control, PWM control, PWM power convertors, Reactive power, single-switch converter, Stress, Switches, switching circuits, Switching frequency, three-phase AC/DC converter, Topology, transformer leakage inductance, Transformers, voltage stress, zero voltage turn-off
AbstractA three-phase AC/DC converter based on isolated Cuk topology feeding an inductive load is presented. The main goal is to get a compact, highly stable current source to feed an electromagnet. A high power factor is achieved, at constant duty-cycle and switching frequency, by discontinuous input current mode operation. The converter presents a linear relationship between the duty-cycle and the output current, making it easier to design the control system. Additionally the voltage stress on the power transistor is constant and does not depend on the duty-cycle. An auxiliary circuit allows zero voltage turn-off while limiting the over-voltage on the switch produced by the transformer leakage inductance. Pulse-width modulation (PWM) control is used to reduce sensitivity to line disturbances and to eliminate the 300-Hz ripple on the output current. Experimental measurements taken on a 400-W prototype confirm theoretical forecasts