32results about How to "Protection against surge voltage" patented technology

In an isolated switching power supply apparatus, by performing on/off control of a first switching device and a second switching device, energy is transmitted from the primary side to the secondary side using a second primary winding and a second secondary winding while the first switching device is on, and energy is transmitted by a first primary winding and a first secondary winding while the second switching device is on. The first secondary winding and the second secondary winding are connected in series with one another, and an inductor is inserted in series to the second secondary winding. An output current is made to flow through the inductor irrespective of whether the first switching device is on or the second switching device is on.

Provided is a driving circuit which suppresses a surge voltage at the time of switching a power semiconductor element and reduces switching loss. An element (10) such as an IGBT and another element (20) to be paired are connected, the element (10) is driven by a driver (22), and a gate voltage is controlled by a control circuit (24). When the power semiconductor element is turned off, a comparator (26) detects that a voltage (Vak) of the element (20) is a prescribed voltage, the control circuit (24) switches gate resistance from low resistance to high resistance to suppress the surge voltage, and the switching loss is reduced. When the power semiconductor element is turned on, start up of the voltage (Vak) is detected, and the control circuit (24) switches the gate resistance from high resistance to low resistance after a prescribed time to suppress the surge voltage, and the switching loss is reduced.

The invention discloses an anti-reverse connection system and method applied to battery management unit equalization channels. The anti-reverse connection system comprises a first interface, a second interface and a field-effect tube, wherein the first interface comprises a first anode and a first cathode; the second interface comprises a second anode and a second cathode; the first anode is connected with the second anode; a grid electrode of the field-effect tube is connected with the first anode, a drain electrode of the field-effect tube is connected with the first cathode, and a source electrode of the field-effect tube is connected with the second cathode. The anti-reverse connection system is controlled by adopting the switching characteristic of the field-effect tube, so that an anti-reverse connection circuit is realized; next, the circuit loss of the part is reduced by using voltage control of the field-effect tube and the characteristic of small on resistance; and then, bidirectional flow of current is realized by using the characteristic of bidirectional conduction after the field-effect tube is connected, and the anti-reverse connection system is applicable to bidirectional equalization channels of battery packs. The anti-reverse connection system can be widely applied to various bidirectional current anti-reverse connection circuit systems.

An ac generator for a vehicle includes a rotor for providing a magnetic field, a stator having a stator core in which a plurality of phase-windings is mounted to generate electromotive force when the magnetic field is supplied, a rectifying unit which includes positive electrode side rectifying elements and negative electrode side rectifying elements respectively connected to the plurality of phase-windings. One of the positive electrode side rectifying element and negative electrode side rectifying element that is connected to a portion of the phase-windings is constituted of a single element and the remainders are constituted of parallelly connected two elements.

A switching power supply apparatus includes a first series circuit including a third rectifier device and a fourth rectifier device and that is connected between a positive output terminal and a negative output terminal, and a first capacitor a first end of which is connected to a connection node between the third rectifier device and the fourth rectifier device and a second end of which is connected to an end, not connected to the first series circuit, of a first rectifier device or a second rectifier device. The first series circuit and the first capacitor define a snubber circuit.