A multi-level converter includes a first blocking device, a second blocking device, a first switching element and a second switching element connected in series between an output terminal of the multi-level converter and ground, a first soft switching apparatus comprising a first auxiliary switch and a first transformer, wherein the first auxiliary switch and the first transformer are configured the first switching element is of zero voltage switching, and the first auxiliary switch is of zero current switching, and a second soft switching apparatus comprising a second auxiliary switch and a second transformer, wherein the second auxiliary switch and the second transformer are configured the second switching element is of zero voltage switching, and the second auxiliary switch is of zero current switching.

The present disclosure provides a control method for an AC-DC conversion circuit. The method includes: calculating working information of an AC-DC conversion circuit according to at least one circuit parameter information of an input voltage, an input current, an output voltage, and an output current of the AC-DC conversion circuit; comparing the working information of the AC-DC conversion circuit with a preset working range to obtain an actual switching frequency or an actual switching period of the AC-DC conversion circuit. The AC-DC conversion circuit can meet requirements of Total Harmonic Distortion (THD), Power Factor (PF), efficiency and Electromagnetic Interference (EMI) and the like by adjusting the working information of the AC-DC conversion circuit through the preset working range.

Disclosed are a switch driving device, in which individual zero voltage switching control of a first switch element and a second switch element forming a bidirectional switch is performed, and a switching power supply including a primary winding to which an alternating-current input voltage is applied, a secondary winding electromagnetically coupled to the primary winding, the bidirectional switch connected in series with the primary winding, a resonance capacitor connected in parallel with at least one of the bidirectional switch and the primary winding, a full-wave rectifier circuit that performs full-wave rectification of an induced voltage occurring in the secondary winding, a smoothing capacitor that smooths output of the full-wave rectifier circuit, and the switch driving device that drives the bidirectional switch. The alternating-current input voltage is directly converted into a direct-current output voltage by extracting a flyback voltage or a forward voltage and the flyback voltage from the secondary winding.

A power converter includes an input coupled to an inductor, a first switch coupled to a first comparator, and a second switch coupled to a second comparator. The power converter also includes a pulse comparison counter coupled to the first comparator and the second comparator and a synchronous rectifier (SR) calculator coupled to the pulse comparison counter. The synchronous rectifier calculator is operable to modify a conduction time of the first switch during a first AC half-cycle and modify a conduction time of the second switch during a second AC half-cycle.

An apparatus for controlling a power converter includes a controller configured to detect an error in an output voltage of the power converter at a zero-crossing of a cyclically varying input signal and a compensator coupled to the controller and the power converter and configured to regulate the output voltage of the power converter in response to the error.

The subject matter of the invention is a resonant DC-DC voltage converter, notably for an electric or hybrid vehicle, said converter including n interleaved main resonant circuits, n being a natural integer greater than or equal to two, and in which: the main resonant circuits are connected together at least one neutral point different from a ground of the converter, said neutral point being connected to a ground of the converter by an impedance configured to store energy and to enable zero voltage switching of the switches of the resonant DC-DC converter.

The present embodiments relate generally to power controllers, and more particularly to synthetic current hysteretic control of a buck-boost DC-DC controller. In one or more embodiments, a controller includes PFM-PWM and Buck-Boost transitions with minimal circuitry and power consumption. In these and other embodiments, a window comparator structure is provided that is capable of generating control signals for use in buck, boost and buck-boost modes of operation.

A load control device for controlling power delivered from an alternating-current power source to an electrical load may comprise a controllably conductive device, a control circuit, and an overcurrent protection circuit that is configured to be disabled when the controllably conductive device is non-conductive. The control circuit may be configured to control the controllably conductive device to be non-conductive at the beginning of each half-cycle of the AC power source and to render the controllably conductive device conductive at a firing time during each half-cycle (e.g., using a forward phase-control dimming technique). The overcurrent protection circuit may be configured to render the controllably conductive device non-conductive in the event of an overcurrent condition in the controllably conductive device. The overcurrent protection circuit may be disabled when the controllably conductive device is non-conductive and enabled after the firing time when the controllably conductive device is rendered conductive during each half-cycle.

An alternating current power tool includes a brushless motor, a power module, a voltage conversion module, a drive circuit, and a controller. The power module is configured to receive an alternating current to supply power to the stator winding. The voltage conversion module is configured to receive the alternating current received by the power module and operatively output a direct current bus voltage. The drive circuit is electrically connected to the voltage conversion module and configured to drive the brushless motor. The controller is configured to start timing when the alternating current received by the power module crosses through a point of zero. In a preset time interval [T1, T2] of each half cycle, a first control signal is outputted to the drive circuit to power on the stator winding.

A zero-crossing detection circuit includes a zero-crossing detection unit arranged to compare a first monitoring target signal and a second monitoring target signal respectively input through diodes from a first node and a second node between which an AC signal is applied, so as to generate a first comparison signal, and a logic unit arranged to estimate a zero cross of the AC signal from the first comparison signal so as to generate a zero-crossing detection signal. The zero-crossing detection circuit preferably includes a monitoring unit arranged to adjust the first monitoring target signal and the second monitoring target signal to be suitable for input to the zero-crossing detection unit. The logic unit preferably counts a period of the first comparison signal and estimates a zero cross of the AC signal using a count value thereof.