Abstract: An inverter for producing AC power from a DC source is disclosed. The inverter uses a transformer and switches to convert current from a battery or other DC source into AC power that can be used to power household appliances or other devices. The primary windings of the transformer are directly connected to a heat sink to which the switches are mounted with electrical connection between the transformer and switches being via the heat sink. The connection point on the heat sink for the primary windings of the transformer is spatially removed from the locations of the switches to facilitate heat dissipation at both locations. The primary windings of the transformer are formed from a tape or ribbon-like conductor having a cross-sectional area that allows the construction of a relatively compact transformer while also providing primary conductors of relatively large cross section.

Abstract: A switched multi-tapped transformer-based power conversion circuit is disclosed. A polarity alternator comprising dual switch devices controlled by a microprocessor selectively periodically impresses across a transformer's center-tapped primary winding a voltage from a battery to produce a modified square waveform. Each of the taps of the transformer's secondary winding synchronously selectively switched by the microprocessor to a common wired-OR junction where the discrete voltage levels combine to produce a stepped approximation of a stored sine waveform. The switching circuits for each of the taps comprises dual back-to-back series-connected FET switches with diodes shunting each FET's source and drain.

Abstract: A high-frequency switching power conversion circuit is disclosed. The circuit is capable of operating either as an inverter or as a rectifier, by the use of an array of high-power, bidirectional switches. AC waveforms are produced by ROM-based pulse width modulation, the clocking of which may be phase-locked to an active AC load. Analog voltage sense circuitry detects high or low output voltage and alters the base address in ROM to a lower or higher duty cycle waveform, respectively, providing digital regulation of the output. Overcurrent protection circuitry, responsive to an inductive load, alters the pulse width modulation pattern to produce a dynamically clamped output dependent upon high-power, variable frequency loads. No-load detection circuitry drastically reduces the duty cycle on the switching elements, thus conserving energy when not needed.

Abstract: An inverter circuit is provided for use with a DC power supply and includes a transformer having a center-tapped primary coil and a secondary coil as well as a switch and a switch controller operating to maintain a constant RMS output voltage. Improvements in the inverter circuit include a switch formed of individual discrete and Darlington transistors connected in parallel so that the discrete transistors predominantly carry the load during low load operation and the Darlington transistor during high load operation.