Abstract: A power supply for converting a variable DC input potential (12) to a regulated DC output potential in accordance with the invention includes a plurality of DC to DC converters (300), each converter operating in response to a DC input potential having an operating range, having an input for receiving a DC input potential which is variable in magnitude, and an output for producing the DC output potential, the outputs of the converters being coupled together; a variable voltage divider (18) having an input coupled to the variable input potential, a plurality of connected stages (100) coupled to the input potential, at least one control signal applied to the variable voltage divider for controlling a number of stages across which the variable input potential is dropped; a switching circuit (200), coupled between the variable voltage divider and the plurality of DC to DC converters, responsive to at least one switching control signal, for coupling an output potential developed by at least one of the stages to at

Abstract: A DC to DC series-parallel resonant converter (10) having a plurality of switches (Q1-Q4) which are switched alternatively between on and off states to cause electrical current to flow alternatively in first and second directions through a series-resonant circuit (60) Including a variable frequency ramp generator (28) having a reset input (R) for casuing an output ramp signal produced at an output to drop to zero in response to each reset signal; a comparator (30) having an input coupled to the output of the ramp signal generator, a second input for controlling the output DC voltage of the series-parallel resonant circuit and an output which changes level each time the ramp signal reaches the magnitude of the second input; a bistable circuit (32) having first and second outputs (Q, Q) for respectively outputting first and second signals, the output signals changing in response to a change in the output signal of the comparator coupled to the input; a pulse generator (26), coupled to the series-parallel resona

Abstract: A system for converting variable frequency multiple phase current into multiple phase current of constant frequency with a neutral having a multiple phase inverter with a neutral (N) is disclosed. A first input (34) is connected to the multiple phase inverter for receiving pulses of a positive polarity. A second input (36) is connected to the multiple phase inverter for receiving pulses of a negative polarity. A variable frequency multiple phase source (12, 14 and 16) of alternating current applies current to a multiple phase transformer (80, 142 and 180). Current from the transformer is applied to a full-wave rectifier (96) which has a first group of diodes (112) which applies the positive pulses to the input (34). A second group of diodes (116) applies the negative pulses to the input (36). The ripple frequency f.sub.

Abstract: An inverter for producing a one or three phase output with neutral is disclosed. An LC resonant circuit is selectively switched by an inverter to produce one or three phases having a fundamental frequency equal to the frequency of each switching circuit within the phases of the inverter. The outputs are filtered to remove higher harmonics to pass the filtered output to the load. Energy is fed back into the resonant circuit by short circuiting the switching circuits at the time that the ouput voltage across a switching circuit is zero to minimize switching losses.

Abstract: Prior DC-DC converters of the resonant type often require the use of parallel-connected power switches to provide adequate current levels and further require large input and output filters. However, parallel operation of switching devices encounters the problem of current sharing and large filters are disadvantageous from a size and weight standpoint. Such problems are overcome by the DC-DC converter of the present invention which includes a plurality of subconverters having outputs which are combined to produce the output power. Each subconverter includes an inverter and a rectifier for developing a full wave rectified output having a ripple component therein. The subconverters are operated so that a phase displacement of 2.pi./N electrical degrees exists in the output current from one subconverter relative to the output current from other subconverters.

Abstract: A controller for a resonant DC/DC converter having at least one power switch which is controlled to develop intermediate AC power in a resonant circuit includes means for developing a signal representing the current in the resonant circuit, an integrator having an input coupled to the developing means for integrating the signal developed thereby and a multiplier having a first input coupled to an output of the integrator and further having a second input and an output at which is developed a multiplied signal. A comparator is coupled to the output of the multiplier for comparing the multiplied signal at such output against a reference signal and a frequency-to-voltage converter is coupled between the output of the comparator and a second input of the multiplier for developing a feedback signal which is multiplied by the multiplier with the output of the integrator to derive the multiplied signal.

Abstract: A proportional base drive circuit which overcomes the problems of the prior art relative to relatively long turn-off time of power switches in an inverter and the absence of protection circuitry therefor includes a current transformer having a primary winding coupled to a main current electrode of a pair of power switches and first and second secondary windings each of which develops regenerative currents proportional to load current. First and second auxiliary switches are coupled between the secondary windings and the control electrodes of the power switches. Means are included for operating the auxiliary switches in synchronism with the power switches so that the power switches operate in rapid fashion. Means are also included for disabling the power switches when an overcurrent condition is sensed.

Abstract: A voltage regulator circuit for a three phase AC generator includes an integrator circuit which integrates the voltage across each negative half cycle of generator output and compares it to a reference voltage to adjust the phase angle of an SCR circuit which provides the power to the exciter field of the generator. A bypass circuit is provided for bypassing the regulating circuit at low generator speeds, the bypass circuit including a FET which directly connects the anode and gate of the SCR in the exciter field power supply to directly apply the generator output voltage to the exciter field at low generator speeds and output voltage. A pair of transistors are latched as the output voltage reaches a preselected minimum value to de-energize the FET and enable the regulator circuit to take over control.