Abstract: A device for load line regulation of a sigma convert is provided. The device comprises a sigma converter comprising an inductor inductor capacitor (LLC) circuit and a buck converter. The device also comprises control circuitry for the sigma converter. The control circuitry is configured to receive a plurality of electrical measurements associated with the sigma converter; determine, based on the plurality of electrical measurements, an adjusted electrical characteristic for load line regulation of the sigma converter; and provide, based on the adjusted electrical characteristic, gating signals to the buck converter to perform the load line regulation of the sigma converter.

Abstract: A soft switching resonant converter is disclosed. The converter includes a power switch operable to connect and disconnect a DC link rail node and an output node. A resonant capacitor is coupled with the power switch. An auxiliary leg is coupled with a DC link midpoint node and the output node. An active damper is coupled in series with the resonant capacitor and the output node and is controllable to provide a first resistance of the active damper in a first state and a second resistance of the active damper in a second state, the first resistance having a lower magnitude than the second resistance. A driver controls the damper switch to provide a first resistance during the soft switching operation of the power switch and a second resistance after the soft switching operation of the power switch.

Abstract: According to one aspect of the present disclosure, a single-stage converter includes a rectifying circuit and a buck-boost circuit. The buck-boost circuit includes an inductor with a center tap configured to supply an output of the buck-boost circuit to the rectifying circuit. The buck-boost circuit also includes first and second interleaved arms arranged in parallel with a voltage input of the single-stage converter. The first and second interleaved arms are each coupled to the inductor and include a plurality of switches operable to control the output of the buck-boost circuit.

Abstract: Unique systems, methods, techniques and apparatuses of photovoltaic (PV) string power systems are disclosed. One exemplary embodiment is a PV power system comprising a plurality of PV strings and a floating DC-DC optimizer. The floating DC-DC optimizer comprises a first DC bus rail, a second DC bus rail, a plurality of input legs, each leg being coupled across the first DC bus rail and second DC bus rail, including two input leg semiconductor switches coupled at an input terminal, each input terminal being structured to receive an input current from an end of one PV string of the plurality of PV strings, and an output leg including two output leg semiconductor devices coupled at an output terminal.

Abstract: A soft switching resonant converter is disclosed. The converter includes a power switch operable to connect and disconnect a DC link rail node and an output node. A resonant capacitor is coupled with the power switch. An auxiliary leg is coupled with a DC link midpoint node and the output node. An active damper is coupled in series with the resonant capacitor and the output node and is controllable to provide a first resistance of the active damper in a first state and a second resistance of the active damper in a second state, the first resistance having a lower magnitude than the second resistance. A driver controls the damper switch to provide a first resistance during the soft switching operation of the power switch and a second resistance after the soft switching operation of the power switch.

Abstract: According to one aspect of the present disclosure, a single-stage converter includes a rectifying circuit and a buck-boost circuit. The buck-boost circuit includes an inductor with a center tap configured to supply an output of the buck-boost circuit to the rectifying circuit. The buck-boost circuit also includes first and second interleaved arms arranged in parallel with a voltage input of the single-stage converter. The first and second interleaved arms are each coupled to the inductor and include a plurality of switches operable to control the output of the buck-boost circuit.

Abstract: According to one aspect of the present disclosure, a single-stage converter includes a rectifying circuit and a buck-boost circuit. The buck-boost circuit includes an inductor with a center tap configured to supply an output of the buck-boost circuit to the rectifying circuit. The buck-boost circuit also includes first and second interleaved arms arranged in parallel with a voltage input of the single-stage converter. The first and second interleaved arms are each coupled to the inductor and include a plurality of switches operable to control the output of the buck-boost circuit.

Abstract: Unique systems, methods, techniques and apparatuses of photovoltaic (PV) string power systems are disclosed. One exemplary embodiment is a PV power system comprising a plurality of PV strings and a floating DC-DC optimizer. The floating DC-DC optimizer comprises a first DC bus rail, a second DC bus rail, a plurality of input legs, each leg being coupled across the first DC bus rail and second DC bus rail, including two input leg semiconductor switches coupled at an input terminal, each input terminal being structured to receive an input current from an end of one PV string of the plurality of PV strings, and an output leg including two output leg semiconductor devices coupled at an output terminal.

Abstract: In one embodiment, a current-fed modular multilevel dual active-bridge DC-DC converter suitable for medium voltage direct current (MVDC) grid or high voltage direct current (HVDC) grid integration is described. The DAB modular converter and the current-fed DAB converter are soft-switched modular multilevel dual-active-bridge (DAB) converters having DC fault ride-through capability. In an additional embodiment a voltage-fed isolated modular dual active-bridge DC-DC converter for medium voltage direct current (MVDC) or high voltage direct current (HVDC) grids or systems is described. In specific embodiments, the converters may be coupled to a battery energy storage system (BESS), wherein the BESS comprises split-battery units and the interface of the isolated DC-DC converter connects the split-battery units to the MVDC or HVDC system.