A class of power converters is disclosed for supplying direct current at one voltage from a source at another voltage which includes a simple passive circuit arrangement of solid-state switches, inductors, and capacitors by which the output voltage of the converter tends to remain constant in spite of changes in load. The switches are sensitive to the current flowing in the circuit and are employed to permit the charging of capacitance devices in accordance with the load requirements. Because solid-state switches (such as SCR's) may be used with relatively high voltage and because of the inherent efficiency of the invention that permits relatively high-switching frequencies, power supplies built in accordance with the invention, together with their associated cabling, can be substantially lighter in weight for a given output power level and efficiency of operation than systems of the prior art.
A D-C voltage converter for controlling the voltage at an inductive load. The circuit is provided with a pulse transformer having first and second primary windings, a secondary winding, and a demagnetizing winding. The second primary winding receives a D-C voltage from a main D-C voltage supply by means of a controlled thyristor. The thyristor in combination with the first primary winding induce currents in the second primary winding and the secondary winding, which maintain a charge on a battery and which supply the inductive load. Electrical energy from the battery is used to produce a countervoltage for extinguishing a thyristor. In addition, circuitry is provided for extinguishing the conduction of the controlled thyristor.
A voltage converter circuit for providing electrical energy to a capacitive load, the converter circuit having a pulse transformer having primary and secondary circuits. Pulse signals are provided in the primary circuit by thyristor devices. The thyristors are quenched by circuitry contained in the secondary circuit, comprising a storage capacitor which conducts a quenching current through a bank of power transistors to at least a portion of a secondary winding. A magnetizing current from a further secondary winding in the secondary circuit is utilized to charge the capacitor.
A high-voltage power supply device comprising a first DC power source, a first reactor supplied with direct current from this first DC power source, a resistor connected in parallel with the first reactor, a current interrupter initially permitting circulation of the flow of current between it and the first reactor and subsequently interrupting the flow of the circulating current therethrough, at least one auxiliary reactor connected in parallel with the first reactor, a second DC power source supplying direct current to the auxiliary reactor, an auxiliary current interrupter initially permitting circulation of the flow of current between it and the auxiliary reactor and subsequently interrupting the flow of the circulating current therethrough, and a diode and switch means connected between the first reactor and the auxiliary reactor. This switch means is turned off when the direct current is supplied to the first reactor from the first DC power source and turned on when the current is supplied to the first reactor from the auxiliary reactor. The high voltage appearing across the resistor in response to the interruption of the flow of the current circulating through the first reactor and the current interrupter is taken up by the diode and is not applied to the auxiliary reactor and the auxiliary current interrupter, so that the auxiliary reactor and the auxiliary current interrupter can be prevented from being destroyed by the high voltage.
A commutation circuit for thyristors alternately turned ON by pulse width modulation (PWM) for the generation of a fundamental sine wave is characterized by two separate primary windings associated with respective positive and negative thyristors with a common secondary winding at the output, and two commutating networks for the respective poles, each including an auxiliary thyristor for fixed-commutation and the resonant combination of a capacitor and an inductor. The thyristors, the commutating networks, the DC source, and the output transformer have a symmetrical disposition as well as symmetrical commutation steps.
A class of power converters which operate between two voltages of continuously variable magnitudes and continuously reversible polarities. It has bidirectional power flow capabilities and some degree of input to output isolation can be provided for. The converter includes a simple circuit arrangement of passive inductors and capacitors and solid state switches controlled in a specific logic sequence so that the output voltage tends to follow a desired reference voltage in spite of limited changes in an either active or passive load. The inherent high efficiency, the relatively high switching frequencies, the possibility of adapting to changing input output wave forms and the suitability to modular construction techniques make power supplies built in accordance with the invention substantially better suited for emergency interfacing systems of different power sources on board airborne or mobile vehicles.
