Northrop Grumman Systems Corporation

Jeffrey C Perkins

John M Rein

Robert M Zawislak

Kenneth John King

A current mode controller for a series resonant power converter having a primary current, a conduction time and a pulse width modulator controller is disclosed. The current mode controller having a current ramp generator in electrical communication with the primary current and being operative to generate a current ramp having a voltage proportional to the primary current. A voltage ramp generator is in electrical communication with the power converter and operative to generate a voltage ramp. The current mode controller further includes a multiplier in electrical communication with the current ramp generator and the voltage ramp generator. The multiplier being operative to generate a time-dependent current ramp having an amplitude proportional to the conduction period of the power converter. A limited voltage ramp generator operative to generate a limited voltage ramp is in electrical communication with the voltage ramp generator. In this respect, the current mode controller further includes an adder in electrical communication with the limited voltage ramp generator and the multiplier and operative to generate a controlling ramp proportional to the limited voltage ramp and the time-dependent current ramp. As such, the adder is in electrical communication with the pulse width modulator controller such that the controlling ramp controls the conduction period of the power converter.

Time compensated current ramp for resonant power converters

A high efficiency power converter for generating a high voltage from a low voltage supply. The power converter includes a resonant circuit in electrical communication with the low voltage supply via a switch. The power converter further includes a control circuit in electrical communication with the switch and a resonant inductor of the resonant circuit. The control circuit is operative to open and close the switch in response to the current flowing through the resonant inductor. A transformer is connected parallel to the resonant inductor and is operative to generate the high output voltage from the voltage of the resonant inductor. In the preferred embodiment, the switch is closed at the point in time when the current in the resonant inductor passes zero. At this time, switching conditions within the switch are ideal such that any losses experienced by the switch are conduction losses thereby resulting in improved efficiency of the power converter.

High efficiency, low voltage to high voltage power converter

A single-stage modular modulator for pulsed illumination sources uses a full-range converter which converts unregulated DC to a 40-50 kHz carrier modulated at a frequency of a few hundred to a few thousand hertz. The modulated carrier is applied to the illumination source through a step-down transformer followed by a low-pass filter circuit which removes the carrier. The converter is controlled by a modulation control which uses an instantaneous load current signal feedback to follow a modulation commend signal, and a current mode signal representing the primary current of the transformer to compensate for converter output variations caused by input voltage variations.

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Roselle, IL, United States of America

Jeffrey C Perkins