International Business Machines Corporation

Hobart Atsushi Higuchi

Lawrence Paul Trubell

Sammy K Yee

This closed loop potential regulated ac-dc power supply comprises a power transformer having two secondary windings and a compensating transformer having two compensating windings connected individually in series circuit with the principal power supply secondary windings. The other secondary windings on the power transformer supply exciting windings for compensating variations in output potential by control of the compensating transformer control circuitry which has an input circuit connected across the load and an output for varying the ac supply to the exciting windings inversely of variations in load potential. A differential amplifying circuit is used for determining the load potential error and driving a transistor effectively to insert a dc component in inverse feedback relationship into the exciting windings of the compensating transformer. As the output potential error increases, the control current is decreased, and conversely. The change in control current flow is enhanced in that the transistor responds immediately to the change in the output potential and additionally by the operation of the differential amplifying circuit.

AC to DC Converter with enhanced buck/boost regulation

The switching circuitry topology is arranged so that the transistors operate in a 1E mode, that is, the voltage across the switching transistors is no greater than the input voltage (E) and at the same time the noise voltage normally generated in regulating circuit arrangements employing transistor switching is greatly reduced. A filter inductor in the primary switching circuit protects the switching transistors from sudden current changes during overload and enables operation of the transistors below the 2E mode. Power is regulated by pulse width control of the switching transistors. One pair of switching transistors is arranged to control the direction of current through the transformer primary winding. Another pair of transistors is arranged for controlling the current in accordance with the width of applied switching pulses. The switch topology also is arranged so that no current ever attempts to flow in the reverse direction through a previously conducting primary circuit diode, hence the rectifying elements are never snapped off, and the less desirable reverse recovery effects are eliminated. Primary-to-secondary circuit isolation is afforded with interchangeable transformer coupling and optocoupling components which also improve immunity to noise.

Regulating electric power circuit arrangement

Standard configuration a.c. power transformer core sections are combined with standard configuration solenoid winding sections to provide a saturable core transformer which is arranged to be driven into saturation by applied alternating and direct current energy with the control of variations in flux changes up to saturation exercised by the direct current flow. A center tapped primary winding is arranged on an I-shaped stack of transformer iron laminations for full-wave excitation. A C-shaped stack of laminations is arranged adjacent to the I-shaped stack and separated by an air gap whereby the primary winding also serves as an input filter choke. The core structure is completed by an E-shaped stack of laminations arranged adjacent to the I-shaped stack and separated by another air gap. Two solenoid windings are arranged on the outer legs of the E-shaped stack and connected to a capacitor for resonating the overall ferroresonant transformer circuit arrangement. Secondary windings are also arranged on the outer legs and connected to a rectifying circuit for supplying direct potential to a load. A control winding is arranged on the central leg of the E-shaped stack of laminations. With this arrangement, the control winding is unaffected by variations in the a.c. voltage as they affect the flux changes in the transformer or in the frequency of the a.c. Regulation of the power supply is executed by direct current flow in the control winding. An adjustable resistor connecting the control winding across the output of the rectifier circuit is often all that is required to complete the circuit. In some applications, an amplifying circuit is used to provide a desired gain in the control winding circuitry.

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San Jose, CA, United States of America

Hobart Atsushi Higuchi