A bidirectional active power conditioner includes a DC side, a bidirectional DC/DC power converter, a DC/AC inverter and an AC side. The DC side electrically connects with a DC source while the AC side electrically connects with a load and an AC source. The bidirectional DC/DC power converter is controlled via high-frequency pulse width modulation (PWM) switching so as to generate a predetermined DC voltage or DC current while the DC/AC inverter is controlled to convert the predetermined DC voltage or DC current into a predetermined AC voltage or AC current.

Bidirectional active power conditioner

A power control circuit includes a switching regulator for converting voltage of external electric power into a medium voltage, a series regulator for converting the medium voltage to a prescribed voltage of output power to be supplied and a circuit for operating either the switching regulator or the series regulator under a protective condition if overvoltage or overcurrent is detected. The switching regulator includes a first transistor, a smoothing circuit and a first control circuit for controlling switching operation of the first transistor. The series regulator includes a second transistor and a second control circuit for controlling conductivity of the second transistor to regulate voltage of the output power to be constant, an overvoltage detecting circuit for detecting an overvoltage of the medium voltage, and an overcurrent detecting circuit for detecting an overcurrent supplied to the series regulator.

Power control circuit

A decanter centrifuge includes a control system for receiving input AC power and outputting a variable voltage and frequency for controlling the speed of the backdrive and the main drive motor. The control system includes a first controller for converting AC power into DC power and then converting the DC power to AC power at a variable voltage and frequency to the main drive motor. A second controller is connected to the first conversion unit through a common DC bus. The second controller converts DC power to AC power and supplies AC power at a variable frequency to the backdrive motor. The braking force created by the backdrive motor during operation of the decanter centrifuge creates electricity which is passed through the second controller and through the common DC bus to the first controller. Thus, the generated power from the backdrive motor is converted into power for use by the main drive motor. A regeneration package may also be provided in order to supply the generated power from the backdrive to the AC input line during decelerating the conveyor when the bowl is simultaneously being decelerated and the main drive motor is also generating power.

Variable frequency centrifuge control

In a multi-phase power converter, efficiency is increased and ripple reduced while maintaining transient response and dynamic performance improved by electrically coupling secondary windings of transformers or provided for inductors of respective phases such that current to a load is induced in each phase by current in another phase. Magnetic coupling can also be provided between phases using a multi-aperture core of a configuration which minimizes primary winding length and copper losses. Efficiency at light load is enhanced by controlling current in the series connection of secondary windings in either binary or analog fashion.

Coupled-Inductor Multi-Phase Buck Converters

A multiple output d.c. to d.c. regulating circuit including an input protection circuit for providing protection against input overcurrent, input transient voltages, sustained input overvoltage and input polarity reversal. The protection circuit powers a d.c. to a.c. inverter which generates high frequency square-wave signals. The square-wave signals are fed to a magnetic saturable reactor regulator which has its controlled windings connected by a rectifying filtering network to a pair of main output terminals and connected by transformer rectifier filter circuits to a plurality of auxiliary output terminals. The d.c. output voltage across the main output terminals is sampled and is compared to a reference voltage of an integrated circuit operational amplifier. The output of the integrated circuit operational amplifier is connected to the control winding of the saturable reactor for controlling the controlled windings so that the square-wave signals are pulse width modulated to regulate the d.c. voltages developed across the pair of main output terminals and the plurality of auxiliary output terminals. A soft starting circuit prevents high in-rushing currents from damaging the d.c. to a.c. inverter. An overload protection circuit senses overloads on the input and main output terminals and causes removal of power from the regulating circuit.

d.c. To d.c. voltage regulator having an input protection circuit, a d.c. to d.c. inverter, a saturable reactor regulator, and main and auxiliary rectifying and filtering circuits

A stabilized DC power supply device providing a plurality of different stabilized DC powers with regulated voltage levels. Stabilized DC powers with rated currents of 2A. or less are taken out from transistor series regulator circuits, another stabilized power with rated current of 8-10A. or more is output from a magnetic amplifier regulator circuit and other powers with rated current of 8-10A. or less are obtained from transistor switching regulator circuits. The regulated voltage output from one of the switching regulator circuits is used as an input DC power for the series regulator circuits and is fed to them through an DC-AC inverter circuit and respective rectifier circuits. Input powers to both the switching regulator circuits and the magnetic amplifier regulator circuit are from a DC power source through a single DC-AC inverter circuit. The device is small in size and good in efficiency. Overvoltage and overcurrent prospective circuits are provided to stop the operation of the DC-AC inverter circuit when either overcurrent or overvoltage occurs.

Kouichirou Ohta

Papers

Stabilized DC power supply device