A Fai 2 converter includes an isolated Fai 2 inverter coupled to a resonant rectifier with either clamped diodes or clamped self-driven synchronous rectifiers. The Fai 2 inverter converts an input DC signal to a high-frequency AC signal. The resonant rectifier with either clamped diodes or clamped self-driven synchronous rectifiers rectifies the high-frequency AC signal to a DC signal while clamping the voltage across the clamped diodes or clamped self-driven synchronous rectifiers to the output voltage. Clamping the voltage in this manner minimizes the voltage stress and enables the use of low voltage stress components (diodes or synchronous rectifiers) with low conduction voltage drop.

A power harvesting system employs a saturable core transformer having two primary windings and at least one secondary winding. One of the primary windings is a high impedance winding, and the other primary winding is a low impedance winding. The two primary windings are connected with the load (motor). The secondary winding provides power to the circuit components of a replacement electronic thermostat. Relay contacts connects A/C power to either the high impedance primary winding or to the low impedance primary winding. When the relay is de-energized, A/C power is applied to the high impedance winding so that a relatively small amount of current flows through both the high impedance winding and the load. This current is low enough that it does not energize the load but is sufficient to generate the required voltage to transfer power to the secondary winding. This power can be used to power an electronic thermostat. When the relay is energized, A/C power is applied directly to the low impedance primary winding, energizing the load. At the beginning of each A/C cycle, the current through the low impedance winding builds up rapidly until the core saturates. The result is that a short pulse is generated in the secondary on both the positive and negative A/C cycle. This pulse has an amplitude determined by the turns ratio of the low impedance winding to the secondary winding and is used to power the electronic thermostat. After the core saturates, the impedance of the low impedance winding is only the resistance of the wire of the winding which is relatively small and results in negligible impact on the load.

A multi-pulse transformer with multiple taps provides a constant magnitude voltage output to a variable speed chiller's compressor motor over a range of input voltages. The 3-phase transformer includes primary windings and a plurality of secondary windings. The secondary windings are electromagnetically coupled with the associated primary winding. The primary windings include taps for receiving multiple input AC voltages and the secondary windings have a single output terminal for supplying a predetermined output voltage which, after rectification produces a DC multi-pulse waveform for powering a DC link of a variable speed drive. Alternatively the 3-phase transformer includes multiple taps on the secondary windings. Each of the primary windings has a terminal for receiving an input AC voltage. The taps of the secondary windings provide an output voltage that is converted to a multi-pulse waveform for powering a DC link of a variable speed drive.

An augmented power converter may include a motor drive circuit. The motor drive circuit may include a motor drive transformer to convert a two-phase DC voltage to a three-phase output voltage for operating an electrical device. The motor drive circuit may also include a power control component for each phase of the two-phase voltage.

Some embodiments include a high voltage direct current (HVDC) power generator system for information technology (IT) racks. The HVDC power generator system can include a three-phase alternating current (AC) transformer having a primary winding and a plurality of secondary windings. A plurality of three-phase bridge rectifier circuits can be electrically coupled respectively to the plurality of secondary windings. The HVDC power generator system can include output terminals for powering its load. A first string of bridge rectifier circuits can be in series with each other and a first inductor. A second string of bridge rectifier circuits can be in series with each other and a second inductor. The first and second strings can be electrically coupled in parallel to the output terminals.

A 12-phase static electrical transformer rectifier including a transformer and first and second three-phase rectifier circuits for coupling to a load, the transformer including a primary circuit having three primary coils arranged in a star configuration and a secondary circuit including three first secondary coils and three second secondary coils that are distinct from the first secondary coils. The secondary circuit of the transformer includes a loop of six secondary coils formed by electrically connecting together the three first secondary coils and the three second secondary coils of the secondary circuit.

A multi-pulse transformer with multiple taps provides a constant magnitude voltage output to a variable speed chiller's compressor motor over a range of input voltages. The 3-phase transformer includes primary windings and a plurality of secondary windings. The secondary windings are electromagnetically coupled with the associated primary winding. The primary windings include taps for receiving multiple input AC voltages and the secondary windings have a single output terminal for supplying a predetermined output voltage which, after rectification produces a DC multi-pulse waveform for powering a DC link of a variable speed drive. Alternatively the 3-phase transformer includes multiple taps on the secondary windings. Each of the primary windings has a terminal for receiving an input AC voltage. The taps of the secondary windings provide an output voltage that is converted to a multi-pulse waveform for powering a DC link of a variable speed drive.

A power harvesting system employs a saturable core transformer having first and second primary windings and a secondary winding. The first primary winding is a high impedance winding with a large number of turns and the second primary winding is a low impedance winding with a small number of turns. The first and second primary windings are connected to a load. A relay is operable in a first state to connect A/C power to the first primary winding and in a second state to connect A/C power to the second primary winding. When A/C power is connected to the first primary winding, a small current flows in the first primary winding which is insufficient to activate the load but sufficient to transfer power to the secondary winding. When A/C power is connected to the second primary winding, a larger current flows in the second primary winding sufficient to activate the load and to transfer power to the secondary winding.

Multiphase lighting fixtures having one or more light emitting diode (LED) light sources are provided. In one example implementation, a light fixture includes one or more light sources, such as LED light sources and a power conversion circuit. The power conversion circuit includes a phase shifting transformer for implementing a phase shift between output phases of secondary windings thereof, a multi-phase rectifier having a first rectifier and a second rectifier connected in parallel for converting a multiphase input power to a rectified output or a six-pulse configuration, a zero sequence blocking transformer for reducing harmonic distortion, an interphase transformer for further reducing harmonic distortion, and a current regulator for providing a constant DC current output to the one or more light sources. In some example implementations, the DC rectified output has a voltage ripple of less than about 7%, or less than about 3%.

An autotransformer for converting three-phase AC power to nine-phase AC power. The autotransformer includes three coils each having serial connected windings and non-serial connected windings. The combination of the serial and non-serial windings are interconnected to form a polygon for a total of six windings per phase, in an arrangement which reduces the power rating of an autotransformer suitable for 18-pulse AC to DC power converters. There are a plurality of direct outputs that are equal in magnitude and are out of phase with respect to the voltages at the input. The input is offset from the nine outputs to create the required phase magnitudes for DC power converters.