Unique systems, methods, techniques and apparatuses of a power converter are disclosed. One exemplary embodiment is a resonant power converter comprising a DC bus, a primary leg, an auxiliary leg, and an LC resonant circuit. The auxiliary leg is coupled between DC bus and includes a first auxiliary switch and a second auxiliary switch coupled at an auxiliary midpoint connection. The LC resonant circuit includes an air-core resonant inductor and a resonant capacitor coupled between the auxiliary midpoint connection and a primary midpoint connection of the primary leg. A controller is structured to control the first and second auxiliary switch and the first and second primary switch so as to provide resonant operation of the LC resonant circuit effective to provide a substantially zero voltage condition across the first and second primary switch while toggling the switches.

The present invention relates to a single phase, non-insulated, miniaturized DC/AC power inverter having an output power density higher than 3000 W/dm.sup.3, wherein said power inverter is packaged in a casing made of an external electrically conductive enclosure containing a fan blowing in an axial direction to a side face of the casing and, in a stacked elevation arrangement, successively from a bottom side to a top side, a layer of active filter capacitors, a heatsink, a layer of wideband semiconductors switches connected to a PCB with thermal vias and a layer of active filtering inductors, the fan and the component stacked arrangement being designed so as, in operation, the external temperature of the casing does not overcome 60 C. in any point, for an ambient temperature of maximum 30 C. under a maximum load of 2 kVA.

In a power conversion apparatus, a controller calculates a duty ratio being a ratio of an on-duration of each of bridge-circuit switches configured by first to fourth switches to a switching period, and outputs a gate signal to each of the bridge-circuit switches. The controller adjusts the duty ratio of each of the bridge-circuit switches such that a switch-current difference becomes closer to a value obtained by multiplying an input-current difference by the predetermined target ratio that is a value greater than 0 and less than 1. The switch-current difference is a difference between a first switch current and a second switch current or a difference between a third switch current and a fourth switch current detected by a switch-current sensor at predetermined timings in the switching period. The input-current difference is a difference between input currents detected by an input-current sensor simultaneously with detection timings of switch currents.

In some implementations, a programmable power adapter includes a first set of switches, a resonant circuit, a transformer, and a second set of switches. The power adapter includes control circuitry configured to provide control signals that change the voltage conversion ratios of the first set of switches and the second set of switches. The control circuitry can provide control signals causing the first set of switches to operate in one of multiple operating modes that each correspond to a different voltage conversion ratio, and the control circuitry can provide control signals causing the second set of switches to operate in one of multiple operating modes that each correspond to a different voltage conversion ratio.

The present invention relates to a bi-directional DC-DC converter comprising: a first terminal, a second terminal, a transformer circuit, a first high voltage side coupled to said first terminal, and a second low voltage side coupled to said second terminal; wherein said first high voltage side and said second low voltage side are coupled to each other by means of said transformer circuit, and said first high voltage side comprises a resonant tank circuit coupled between a first bridge circuit of said first high voltage side and a high voltage side of said transformer circuit. Furthermore, the invention also relates to a system comprising at least two such bi-directional DC-DC converters.

The invention relates to a converter (10), especially for use at high voltage ratios, characterized by a cascade of at least two steps, wherein at least the first step is made of a resonant unit (15), which comprises at least one inductive reactance unit, in particular at least one piezoelectric resonator, and at least one capacitor unit, which are connected in series.

In an example, a controller device for a resonant converter includes processing circuitry configured to output a first switching signal and a second switching signal. A switching module is configured to electrically couple a primary side winding of a transformer to a voltage source during an activated state of the first switching signal and to electrically couple the primary side winding to a reference node during an activated state of the second switching signal. The processing circuitry is further configured to determine a first synchronous rectification signal and a second synchronous rectification signal. A synchronous rectification module is configured to generate a first channel for a first secondary side winding of the transformer during an activated state of the first synchronous rectification signal and to generate a second channel for a second secondary side winding of the transformer during an activated state of the second synchronous rectification signal.

In a power conversion apparatus, a controller calculates a duty ratio being a ratio of an on-duration of each of bridge-circuit switches configured by first to fourth switches to a switching period, and outputs a gate signal to each of the bridge-circuit switches. The controller adjusts the duty ratio of each of the bridge-circuit switches such that a switch-current difference becomes closer to a value obtained by multiplying an input-current difference by the predetermined target ratio that is a value greater than 0 and less than 1. The switch-current difference is a difference between a first switch current and a second switch current or a difference between a third switch current and a fourth switch current detected by a switch-current sensor at predetermined timings in the switching period. The input-current difference is a difference between input currents detected by an input-current sensor simultaneously with detection timings of switch currents.

In an example, a controller device for a resonant converter includes processing circuitry configured to output a first switching signal and a second switching signal. A switching module is configured to electrically couple a primary side winding of a transformer to a voltage source during an activated state of the first switching signal and to electrically couple the primary side winding to a reference node during an activated state of the second switching signal. The processing circuitry is further configured to determine a first synchronous rectification signal and a second synchronous rectification signal. A synchronous rectification module is configured to generate a first channel for a first secondary side winding of the transformer during an activated state of the first synchronous rectification signal and to generate a second channel for a second secondary side winding of the transformer during an activated state of the second synchronous rectification signal.

In some implementations, a programmable power adapter includes a first set of switches, a resonant circuit, a transformer, and a second set of switches. The power adapter includes control circuitry configured to provide control signals that change the voltage conversion ratios of the first set of switches and the second set of switches. The control circuitry can provide control signals causing the first set of switches to operate in one of multiple operating modes that each correspond to a different voltage conversion ratio, and the control circuitry can provide control signals causing the second set of switches to operate in one of multiple operating modes that each correspond to a different voltage conversion ratio.