Systems and methods for an alternating current (AC) input selection for a power transformer are disclosed. In particular, a connector is provided that is pre-wired to utilize internal wiring in the power transformer to provide a desired connection. A first option allows two transformers' input winding to be in series while a second option allows the two transformers' input winding to be in parallel. By moving the wiring into the connector, installation is simplified as the wiring has already been done. The installer need only attach the correct plug based on the desired voltage and couple the plug to the transformer. Further, the manipulation of thick wires is also avoided by the installer, further simplifying the installation process.

A modular power conversion system is provided which includes a plurality of building blocks comprised of transformers and power conversion bridges, and a high frequency AC link that transfers power and provides galvanic isolation between the building blocks. The high frequency link includes an insulating tube separating an AC link conductor and the building blocks. The insulating tube is further provided with conductive or semiconductive layers on its inner and outer surfaces for referencing them to the electric potentials of the adjacent conductors and windings, thereby placing the high electric fields substantially directly across the tube and reducing electric fields and partial discharge or corona in the adjoining space or media. The building blocks may be arranged in multiple stacks for DC or AC interface, preferably with neutral or lower voltage connections at the outer edges of the stacks and higher voltage terminals at the centers of the stack.

A modular power conversion system is provided which includes a plurality of building blocks comprised of transformers and power conversion bridges, and a high frequency AC link that transfers power and provides galvanic isolation between the building blocks. The high frequency link includes an insulating tube separating an AC link conductor and the building blocks. The insulating tube is further provided with conductive or semiconductive layers on its inner and outer surfaces for referencing them to the electric potentials of the adjacent conductors and windings, thereby placing the high electric fields substantially directly across the tube and reducing electric fields and partial discharge or corona in the adjoining space or media. The building blocks may be arranged in multiple stacks for DC or AC interface, preferably with neutral or lower voltage connections at the outer edges of the stacks and higher voltage terminals at the centers of the stack.

A method of controlling power applications for a power transformer in a heating ventilation and cooling system (HVAC). The method includes measuring a voltage output of a transformer, the transformer configured to supply control power to a component of the HVAC system, determining a loading of the transformer; prioritizing a loading of the transformer; and applying the prioritization to mitigate loading constraints associated with the transformer.

A method of controlling power applications for a power transformer in a heating ventilation and cooling system (HVAC). The method includes measuring a voltage output of a transformer, the transformer configured to supply control power to a component of the HVAC system, determining a loading of the transformer; prioritizing a loading of the transformer; and applying the prioritization to mitigate loading constraints associated with the transformer.

A system for plasma ignition and maintenance of an atmospheric pressure plasma. The system has a variable frequency alternating current (AC) power source, a transformer, a cable connected to a secondary winding of the transformer, a programmed microprocessor for control of power to the atmospheric pressure plasma. The microprocessor is configured to a) at pre-ignition, power the AC power source at an operational frequency f.sub.op higher than the resonant frequency f.sub.r, b) decrease the operational frequency f.sub.op of the AC power source until there is plasma ignition, and c) after the plasma ignition, further decrease the operational frequency f.sub.op of the AC power source to a frequency lower than the resonant frequency f.sub.r.

A solid-state transformer (SST) comprises a transformer core, a primary winding, a secondary winding, a primary-side switch bank, and a secondary-side switch bank. Each of the switch banks includes six 4-quadrant switches. The twelve 4-quadrant switches are toggled on and off over six clock cycles in a repetitive sequence with a period that is a function of a desired operating frequency of the transformer. The sequence is configured such that at any given time, 2 of 3 input and output phases are connected to the primary and secondary windings. The SST further includes L-C filter circuits that are configured to filter high-frequency components of current and voltage waveforms such that these components are not back-fed to the electrical mains or delivered to a load. The SST includes a primary-side filter circuit and a secondary-side filter circuit that can each include respective L-C filters for three input or output phases.

A transformer configured for use in connection with a variable speed motor drive includes primary windings and secondary windings. The secondary windings are configured as wye-windings and a ground lead and a plurality of phase leads. The transformer includes a ferrite blocking circuit connected to the ground lead.

The present disclosure relates to a voltage regulation circuit (100). The voltage regulation circuit (100) comprises a transformer (130) having a primary winding (132) having a first end (132A) and a second end (132B), and a first secondary winding (134) having a first end (134A) and a second end (134B), wherein the first end (132A) of the primary winding (132) is configured to receive an input voltage and the second end (132B) of the primary winding (132) is configured to produce an output voltage, wherein the first end (134A) of the first secondary winding (134) is connected to a neutral node (180), wherein the primary winding (132) produces a primary voltage based on the input voltage, and wherein a secondary voltage of the first secondary winding (134) is out-of-phase to the primary voltage of the primary winding (132); and a first switch (160) configured to connect the second end (134B) of the first secondary winding (134) with the second end (132B) of the primary winding (132), wherein, when the first switch (160) is connected, the output voltage is the secondary voltage.

Aspects of the invention overcome a monolithic approach to conventional low-frequency LPTs by using a high-frequency solid-state alternating current ac/ac modular power-conversion approach. Embodiments of the invention enable the ability to incorporate new technologies without in all cases redoing a LPT design from scratch. Furthermore, given that LPTs are for the long term, aspects of the invention ensure that they are durable, efficient, and fault tolerant with overloading capability.