Various examples are provided for soft switching solid state transformers and converters, and their operation and application. In one example, a soft switching solid state power transformer includes a high frequency (HF) transformer; first and second auxiliary resonant circuits coupled to the HF transformer; and first and second current-source inverter (CSI) bridges coupled to the corresponding first auxiliary resonant circuits. The first and second CSI bridges include reverse blocking switch assemblies that conduct current in one direction and block voltage in both directions. In another example, a reactive power compensator includes a high frequency (HF) transformer, first, second and third auxiliary resonant circuits coupled to the HF transformer, and first, second and third current-source inverter (CSI) bridges coupled to the corresponding first auxiliary resonant circuits. In another example, a converter includes an auxiliary resonant circuit coupled across an inductor and first and second CSI bridges coupled across the inductor.

Unique systems, methods, techniques and apparatuses of a modular power transformer are disclosed. One exemplary embodiment is a matrix power transformer including a plurality of block assemblies each including a plurality of transformer modules, each transformer module including a primary winding coupled to an input and a secondary winding coupled to an output, the inputs of each transformer module in one block assembly being coupled together and the outputs of each transformer block being coupled together. One of the secondary windings includes a plurality of taps structured to be selectively coupled to the output of the associated transformer module assembly or another secondary winding of the associated module assembly.

A method for wirelessly or conductively (non-wireless) providing AC or DC power in AC or DC load applications and bidirectional applications.

Various examples are provided for soft switching solid state transformers and converters, and their operation and application. In one example, a soft switching solid state power transformer includes a high frequency (HF) transformer; first and second auxiliary resonant circuits coupled to the HF transformer; and first and second current-source inverter (CSI) bridges coupled to the corresponding first auxiliary resonant circuits. The first and second CSI bridges include reverse blocking switch assemblies that conduct current in one direction and block voltage in both directions. In another example, a reactive power compensator includes a high frequency (HF) transformer; first, second and third auxiliary resonant circuits coupled to the HF transformer; and first, second and third current-source inverter (CSI) bridges coupled to the corresponding first auxiliary resonant circuits. In another example, a converter includes an auxiliary resonant circuit coupled across an inductor and first and second CSI bridges coupled across the inductor.

An exemplary embodiment provides a power conversion system comprising a first battery module, a second battery module, first and second transformers, and first, second, and third current source converter bridges. The transformers can have low voltage sides and high voltage sides. The first bridge can be configured to connect the battery modules and the low voltage sides of the transformers. A mid-point of the serial connection of the battery modules can be connected to a mid-point of the series connection of the transformers. The second bridge can connect to the high voltage side of the first transformer and one or more ports configured to transmit electrical power to and/or receive electrical power from an electrical load and/or source. The third bridge can be configured to connect to the high voltage side of the second transformer and the one and one or more ports.

A power converter includes a multiple-winding transformer. The multiple-winding transformer provides an electromagnetic link between an input side and an output side of the power converter. An inductor is arranged on at least one of the input side and the output side of the power converter in parallel with the multiple-winding transformer. At least one first capacitor is arranged on the input side of the power converter in parallel with the multiple-winding transformer and the inductor. At least one second capacitor is arranged on the output side of the power converter in parallel with the multiple-winding transformer. The inductor, the at least one first capacitor, and the at least one second capacitor define a parallel resonance tank. A first plurality of switching devices is arranged on the input side. A second plurality of switching devices is arranged on the output side.

We disclose herein a power coupler for connecting AC or DC electrical circuits having different voltages, current or impedance levels. The power coupler comprise a first switching device; a second switching device coupled with the first switching device; a power transformer comprising a first core winding and a second core winding; a first capacitance coupled between the terminals of the first core winding; a second capacitance coupled between the terminals of the second core winding; and a third capacitance coupled between the first and second cores windings. The power transformer is coupled with the first and second switching devices. The power coupler is configured to reduce switching power loss using an adiabatic technique and by selecting appropriate switching time of the switching devices.

A power converter circuit includes a plurality of first converter cells, a plurality of second converter cells, and a plurality of DC link capacitors. Each of the plurality of first converter cells is coupled to a corresponding one of the plurality of DC link capacitors. Each of the plurality of second converter cells is coupled to a corresponding one of the plurality of DC link capacitors. At least one of the plurality of second converter cells is configured to, during start-up of the power converter, internally dissipate power received from the corresponding DC link capacitor while a cell output power of the at least one of the plurality of second converter cells is substantially zero.

A method of decoupled modulation of a direct AC/AC MMC between a first AC network having a first waveform and a second AC network having a second waveform, the MMC having a double-star topology with a plurality of phase legs, each phase leg having a first branch and a second branch, each of the first and second branches comprising a plurality of series connected bipolar cells. The method includes performing a first modulation based on a reference signal of the first AC network, independently of a reference signal of the second AC network, to generate, for each phase leg, a first integer command signal corresponding to a first combination of cell states in the first and second branches of the phase leg needed for generating the first waveform. The method also comprises performing a second modulation based on the reference signal of the second AC network, independently of the reference signal of the first AC network to generate, for each phase leg, a second integer command signal corresponding to a second combination of cell states in the first and second branches of the phase leg needed for generating the second waveform. The method also includes, based on the first and second integer command signals, mapping to each branch a number of cell states to be used for concurrently generating both the first and second waveforms, generating branch-level command signals to a capacitor voltage balancing algorithm. The method also includes, based on the mapping and the balancing algorithm, sending firing signals to the plurality of cells of each branch.

An energy control circuit is provided. The energy control circuit includes an input circuit; an output circuit; an energy storage circuit coupled between the input circuit and the output circuit; and a controller coupled to the input circuit and output circuit for controlling an amount of energy stored in the energy storage circuit and for controlling a waveform generated by the output circuit using energy stored in the energy storage circuit.