A resonant power converter. An embodiment with a fullbridge converter is disclosed, controlled with feedback or feedforward technique. Switching schemes are either based on a sort of look up table or on measurement of current or voltage. Dead time may be adjusted. Timing may be such, that in the respective diagonal pairs of the converter, one switch is switched on for a different time (different pulse width) than the other. Use in a relative high power environment for about 20 KW in e.g. an X-Ray or Computer Tompgrapy System.

An AC/DC conversion apparatus includes first, second, and third AC/DC conversion modules operated by a controller in two modes of operation. In the first mode, the input AC signal is 3-phase and each of the three modules are enabled to handle a respective one of the input phases. In the second mode, the input AC signal is single phase and the first and second modules are enabled to deliver output power based on the single-phase AC input, while the controller actuates an H-bridge switches in the third module to which active filter circuitry is connected, to reduce an AC component in the output signal. The active filter circuitry can be selectively connected to the H-bridge switches when single-phase operation is desired, which circuitry may be disposed in a filter housing having male electrical terminals that cooperate with corresponding female terminals associated with the third module.

A DC-AC converter is disclosed. The DC-AC converter generates an output AC signal, and has an input DC-AC converter which generates a first AC signal, a transformer device which receives the first AC signal and generates a second AC signal, and a first bidirectional switch which selectively connects a first transformer output terminal and a first output terminal. The DC-AC converter also has a first capacitor which powers the first bidirectional switch, a first charging circuit which charges the first capacitor, and a second bidirectional which selectively conduct connects a second transformer output terminal and a second output terminal. The DC-AC converter also has a second capacitor which powers the second bidirectional switch, and a second charging circuit which charges the second capacitor. Each of the bidirectional switches includes series connected transistors between first and second input/output terminals, and a transistor driver which drives the transistors.

An isolated power conversion apparatus has an isolation transformer, a series circuit including a load and an inductor connected in series with each other, the series circuit being disposed on a secondary side of the isolation transformer, and one or a plurality of switching means disposed between the series circuit and the secondary side of the isolation transformer, the switching means being bidirectional. This apparatus sends out power from a DC power supply of a primary side of the isolation transformer toward the load as DC power or AC power of an arbitrary polarity, or regenerates and supplies the DC power or AC power from the load to the DC power supply.

A two-stage converter, a method for starting the two-stage converter, an LLC converter, and an application system are provided. A controller of the LLC converter of the two-stage converter first controls a main circuit of the LLC converter to perform hiccup charging on a direct current bus of a later-stage converter at a preset interval, so that the direct current bus voltage of the later-stage converter gradually increases, until an auxiliary power supply of the later-stage converter starts to operate, to supply power to the controller of the later-stage converter. After the controller of the later-stage converter reports the detected direct current bus voltage, the controller of the LLC converter determines whether the output voltage of the LLC converter increases to a hiccup starting voltage. If so, the controller of the LLC converter controls the main circuit to operate in a hiccup voltage stabilization phase.

The present invention relates to a power conditioning unit for delivering power from a dc power source to an ac output, particularly ac voltages greater than 50 volts, either for connecting directly to a grid utility supply, or for powering mains devices independent from the mains utility supply. We describe a power conditioning unit for delivering power from a dc power source to an ac mains output, the power conditioning unit comprising an input for receiving power from said dc power source, an output for delivering ac power, an energy storage capacitor, a dc-to-dc converter having an input connection coupled to said input and an output connection coupled to the energy storage capacitor, and a dc-to-ac converter having an input connection coupled to said energy storage capacitor and an output connection coupled to said output, wherein said energy storage capacitor has a capacitance of less than twenty microfarads.

The apparatus of present invention converts AC or DC power sources to AC or DC power loads, in a single stage, bidirectionally, employing variable, high frequency resonant circuits and power switches, to continuously vary the gain of the conversion circuit. Inrush current control, idle converter turn off, line voltage brown out protection, soft start, high pre-charge voltage generation, soft shut down, and dimming operation are inherent characteristics of the apparatus of the instant invention. A remotely configurable and operable controller may optionally be used to control the mode of conversion, the amplitude and frequency of the output voltages. The resonant circuits can be paralleled to derive multiple outputs. Multiple converter stages can be cascaded to meet the various power needs of an application such as multiple outputs and different amplitudes. Components can be eliminated for specific conversion applications. The circuits can be implemented in semiconductor packages.

An inverter device includes a converter circuit and an output circuit. The converter circuit generates a DC intermediate voltage based on a DC input voltage from a power source. The converter circuit includes: a first inductor and a first switch that are coupled in series across the power source; a second switch and a second inductor that are coupled in series across the power source; and a diode and a capacitor that are coupled in series between a common node of the first inductor and the first switch and a common node of the second switch and the second inductor. The output circuit generates an AC output voltage based on the DC intermediate voltage across the capacitor.

A three-phase power supply system includes three phase branches forming a delta connection. Each of the phase branches includes at least one power conversion cell of at least two stages. The at least one power conversion cell of each of the phase branches is connected in parallel to the at least one power conversion cell of the respective other two phase branches. When one of the phase branches stops operating, the other two phase branches keep operating, and three phase current of the three-phase power supply system can be balanced by regulating active powers and reactive powers of the other two phase branches. Through the invention, when one of the phase branches stops operating, the other two phase branches may keep operating, and three phase current of the three-phase power supply system are balanced.

A conversion device comprises: an inductor electrically connected to the AC power grid; a first-stage converter configured to output a bus voltage according to the AC power grid, wherein the first-stage converter comprises an N-level alternating current-direct current (AC-DC) converter, and the N-level AC-DC converter comprises a plurality of switch bridge arms, wherein both an upper bridge arm and a lower bridge arm of each of the plurality of switch bridge arms of the N-level AC-DC converter include a plurality of semiconductor devices connected in series, and a rated withstand voltage Vsemi of each of the semiconductor devices is greater than or equal to (Vbus*δ)/((N−1)*Nseries*λ); and a second-stage converter configured to convert the bus voltage into an output voltage to supply energy to the load.