Abstract: A phase adaptable AC/DC converter having three input terminals capable of connection to either a single phase or dual phase electrical power service. A feedback circuit in a control portion of the converter sums a first voltage and a second voltage which are proportional to first and second output voltages, respectively, to control a first bidirectional switch in a voltage boost circuit. The feedback circuit also sums the first and second voltage with a difference between the first and second output voltages to control a second bidirectional switch in the voltage boost circuit.

Abstract: An apparatus is disclosed which is capable of conditioning any of a variety of utility service AC power inputs having distortion and noise into a clean AC power signal at the output by using symmetrical topology. The present invention is capable of maintaining a constant voltage amplitude at the output while the input utility voltage amplitude varies, and attenuates any distortions present at the input. The present invention first comprises a boost converter comprised of four semiconductor switches in parallel with a diode bridge to convert the incoming AC signal into a DC signal which is stored on two storage capacitors. Secondly, using a buck inverter, the stored DC signal is reconverted into a clean AC signal applied to the output. Input and output filters are used to help clean the signal, and chokes are used to help separate damaging signals produced by the converter and inverter from the storage capacitors.

Abstract: A multiphase common mode transient suppressor is disclosed which uses a plug choke placed at the utility power service input to the circuit of the present invention. The plug choke contains, for example, three coils corresponding to three power carrying input conductors. Each coil is wound in the same direction, and has the same number of turns. Preferably, a magnetic core is provided around which the coils are wound. At the output of the plug choke are placed three capacitors, in parallel between a grounding conductor and three output conductors. The choke in combination with the capacitors creates a resonant circuit.A control circuit is provided which is connected to the plug choke via a catcher coil. The catcher coil "catches" the flux induced by the transient and dissipates its energy through a resistor, thus dampening the resonant circuit. Current through the resistor is controlled by a semiconductor switch.

Abstract: A half-bridge inverter circuit is provided for converting a DC voltage source to an AC voltage waveform, and supplying the AC voltage waveform to a load. The half-bridge inverter includes an inverter comprising a first capacitor for supplying a positive output voltage and a second capacitor for supplying a negative output voltage during respective intervals of the output waveform. An equalizer, responsive to a control circuit, equalizes the voltage output from the first capacitor and the second capacitor in order to overcome non-symmetry of these voltages resulting from a non-symmetrical load.

Abstract: An uninterruptible power supply is disclosed which is cheaper and more adaptable to various utility service inputs than presently available power supplies. A storage capacitor is placed between a boost AC/DC converter at the input and a DC/AC inverter at the output. A storage battery for maintaining constant voltage should the utility service power be interrupted is placed at the input, before the boost converter. Thus, a small battery is required because the boost converter is capable of boosting the battery's voltage to the voltage contained on the storage capacitor. A bidirectional semiconductor switch is provided in the boost converter to allow current to flow in both directions between its switch terminals when a AC input is applied. Appropriate control circuitry is provided which monitors the voltage at specific points throughout the circuit and controls operation of the bidirectional switch.