A vehicle-based high-voltage charging circuit is provided with an AC voltage terminal, at least two galvanically isolating DC-DC converters designed as step-up converters and a rectifier via which the DC-DC converters are connected to the AC voltage terminal, and a changeover switch. The charging circuit has a first and a second DC voltage terminal selectably connected to the first DC-DC converter via the changeover switch. The charging circuit has a third DC voltage terminal connected to the second DC-DC converter, wherein the charging circuit also has a controller which is set up, in a first mode, to drive the DC-DC converters according to a first target output voltage which is at least 750 V and at most 1000 V, and, in a second mode, to drive the DC-DC converters according to a second target output voltage which is at most 480 V or at most 450 V.

A multi-level inverter topology is disclosed. A power converter circuit converts a DC source at its input to provide an alternating current (AC) at its output. The power converter circuit may have a controller operably attached to multiple series connections of switches. The controller may control one or more of the multiple series connections of switches to convert a DC input to provide multi-level AC voltages with DC offset across two terminals of the power converter circuit. The multi-level AC voltages with DC offset may then be converted by use of a plurality of series connections of switches to provide a single-phase AC voltage at a first output terminal with respect to at least one of a neutral potential, an earth potential, or a terminal of the power converter circuit.

A multi-level inverter topology is disclosed. A power converter circuit converts a DC source at its input to provide an alternating current (AC) at its output. The power converter circuit may have a controller operably attached to multiple series connections of switches. The controller may control one or more of the multiple series connections of switches to convert a DC input to provide multi-level AC voltages with DC offset across two terminals of the power converter circuit. The multi-level AC voltages with DC offset may then be converted by use of a plurality of series connections of switches to provide a single-phase AC voltage at a first output terminal with respect to at least one of a neutral potential, an earth potential, or a terminal of the power converter circuit.

A circuit for use in a switched mode power supply includes a dual-boost power-factor correction converter having an active rectifier stage with first and second rectifier transistors and first and second boost stages each with an inductor and transistor. An active rectifier controller circuit generates control signals for driving the rectifier transistors, respectively, on and off in accordance with an AC input voltage. A PFC controller circuit generates a pulse-width-modulated (PWM) control signal that is based on an output voltage of the boost stages and which is further based on a current sense signal representing the current passing through the active rectifier stage. A logic circuit generates a control signal for the transistor of the first boost stage and a control signal for the transistor of the second boost stage, based on the PWM control signal and at least one of the control signals for the rectifier transistors.

A resonant inductive power transfer circuit has a power converter to supply to a load, and the converter is concurrently controlled to create a controlled reactance that substantially compensates for variability in the coupling with the another resonant inductive power transfer circuit and/or changes in the load supplied by the power converter.

An apparatus for modular AC to AC frequency conversion is disclosed. An input AC source is configured to generate an input AC voltage at a first frequency. At least one primary low frequency (LF) conversion stage is configured to generate a DC voltage, and comprises a first pair of metal-oxide-semiconductor field effect transistors (MOSFETs). At least one primary high frequency (HF) conversion stage is configured to generate the DC voltage, and comprises a first pair of high electron mobility transistors (HEMTs). At least one secondary LF conversion stage is configured to receive the DC voltage and generate an output AC voltage at a second frequency, and comprises a second pair of MOSFETs. At least one secondary HF conversion stage is configured to receive the DC voltage and generate the output AC voltage at the second frequency, and comprises a second pair of HEMTs.

The invention provides a power converter for converting a three-phase alternating current (AC) supply to a direct current (DC) output, the power converter comprising: a first selector configured to select one of the highest, the second highest or the lowest instantaneous phase to phase voltages of the three-phase supply to provide a first power rail; a second selector configured to select a different one of the highest, the second highest or the lowest instantaneous phase to phase voltages of the three-phase supply to provide a second power rail; a first transformer coupled to the first power rail; a second transformer coupled to the second power rail; a combiner configured to combine the outputs of the first and second transformers to provide the DC output; and a duty cycle controller configured to vary duty cycles of the first and/or second transformers to thereby vary the relative contributions of the first and second power rails to the DC output.

The invention provides a power converter for converting a three-phase alternating current (AC) supply to a direct current (DC) output, the power converter comprising: a first selector configured to select one of the highest, the second highest or the lowest instantaneous phase to phase voltages of the three-phase supply to provide a first power rail; a second selector configured to select a different one of the highest, the second highest or the lowest instantaneous phase to phase voltages of the three-phase supply to provide a second power rail; a first transformer coupled to the first power rail; a second transformer coupled to the second power rail; a combiner configured to combine the outputs of the first and second transformers to provide the DC output; and a duty cycle controller configured to vary duty cycles of the first and/or second transformers to thereby vary the relative contributions of the first and second power rails to the DC output.

An image display device of the present invention comprises a display and a power supply unit, and the power supply unit comprises: a first voltage detection unit that detects an input AC voltage by using a first resistance element; a second voltage detection unit that detects an input AC voltage by using a differential circuit having a capacitor element and a second resistance element; a converter that converts the level of the input voltage on the basis of a switching operation of a switching element so as to output a DC voltage; and a control unit that may control the switching element in the converter to be turned on, on the basis of a first signal detected by the first voltage detection unit or a second signal detected by the second voltage detection unit. As such, the present invention operates stably even when an AC voltage of a square wave is applied.

An image display device of the present invention comprises a display and a power supply unit, and the power supply unit comprises: a first voltage detection unit that detects an input AC voltage by using a first resistance element; a second voltage detection unit that detects an input AC voltage by using a differential circuit having a capacitor element and a second resistance element; a converter that converts the level of the input voltage on the basis of a switching operation of a switching element so as to output a DC voltage; and a control unit that may control the switching element in the converter to be turned on, on the basis of a first signal detected by the first voltage detection unit or a second signal detected by the second voltage detection unit. As such, the present invention operates stably even when an AC voltage of a square wave is applied.