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

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.

In a power converter, a plurality of semiconductor devices and a plurality of cooling plates are stacked. The plurality of semiconductor devices includes a first-first sealed semiconductor device, a second-first sealed semiconductor device, and a plurality of second sealed semiconductor devices. The first-first sealed semiconductor device has a first high potential side terminal, and a first low potential side terminal. The second-first sealed semiconductor device has a second high potential side terminal, and a second low potential side terminal. When viewed along a stacking direction, the first high potential side terminal is disposed to overlap with the second low potential side terminal.

The invention relates to a method for preventing a surge used for an electronic jacquard machine. The electronic jacquard machine consists of a control system and a plurality of electromagnetic needle-selector drive plates controlled by the control system. Each electromagnetic needle-selector drive plate drives a plurality of electromagnetic needle-selector coils. A time-delay unit is connected with the branch circuit, which is connected with the electromagnetic needle-selector drive plate, in sequence, each branch circuit has a different delay time and the delay time of a plurality of branchcircuits forms a time-delay sequence. When the control system needs the electromagnetic needle-selector coil to be electrified, the electromagnetic needle-selector coils connected with the branch circuits are electrified in sequence under the control of the time-delay unit. When the control system needs the electromagnetic needle-selector coil to be powered-down, the electromagnetic needle-selector coils connected with the branch circuits are powered-down in sequence under the control of the time-delay unit. The method can effectively reduce the surge current and surge voltage due to the factthat the loads are electrified or powered-down at the same time.

The invention provides a DC to DC converting circuit, comprising: a transforming unit with a primary winding and a secondary winding; a bridge rectifier unit coupled to an input voltage, having a first output terminal and a second output terminal coupled to both side of the primary winding respectively; a first switch coupled between the input voltage and the first output terminal; a second switch coupled between the first output terminal and a ground terminal; a third switch coupled between the input voltage and the second output terminal; and a fourth switch coupled between the second output terminal and the ground terminal; an output unit paralleled to the secondary winding; and a clamping unit coupled to the input voltage and paralleled to the bridge rectifier unit, having an auxiliary switch coupled to the input voltage; and a clamping capacitor coupled between the auxiliary switch and the ground terminal; wherein the auxiliary switch is turned on when operation statuses of the first switch and the fourth switch or the second switch and the third switch are changed.

An LDO (low dropout regulator) comprises anovervoltage power device, a voltage detection circuit, a first control circuit and a second control circuit, wherein the voltage detection circuit is suitable for detecting power voltage to produce a detection signal, and the detection signal is output by the voltage detection circuit; the first control circuit is suitable for controlling the detection signal according to a control signal, so that the detection signal is of first logic level in preset time interval after power on and is of second logic level different from the first logic level after the preset time interval; the second control circuit is suitable for controlling the overvoltage power device according to the detection signal, controls the overvoltage power device to be switched off in response to the detection signal being of the first logic level and removes control on the overvoltage power device in response to the detection signal being of the second logic level. Surge voltage output by the LDO can be inhibited effectively with adoption of the scheme.

A control apparatus controls an optimizer that steps up a DC input voltage from a solar photovoltaic power generation panel to a predetermined DC high voltage and converts the stepped-up DC voltage into a grid connection voltage, and includes a microprocessor; a sensor group; and a MOS driver group. The microprocessor includes: a control logic unit; a maximum power point tracking control unit; a PWM control unit; a PFM control unit; an I / O port; a timer control unit; and an initial measurement unit. The sensor group includes a solar photovoltaic panel voltage detection circuit; a solar photovoltaic panel current detection circuit; an optimizer output voltage detection circuit; and an optimizer output current detection unit. Thus, even when the solar photovoltaic power generation panel is at a low power in a low output state, stable operation can be continued, and transistors can be protected from a surge voltage.

The invention discloses a power supply system for an electron gun power supply, comprising an electron gun filament and a filament transformer, the primary coil of the filament transformer is connected to a high-voltage electrode, the secondary coil is connected to the electron gun filament, and the primary coil of the filament transformer is connected to a high-voltage electrode. At least one potentiometer is also connected between the electrodes, and each potentiometer adjusts its resistance value through an insulating rod, and the insulating rod is driven by a stepping motor. The invention solves the problem that the ordinary power supply in the prior art cannot complete the power supply to the electron gun, and adjusts the primary current of the filament transformer by adjusting the two potentiometers of the primary circuit of the filament transformer to change the high-frequency current of the heating filament to adjust the electron current intensity of the accelerator. Objective: The electron beam current is easy to adjust, the electron beam current is stable, and the problem of supplying power to the electron gun at a high potential is well solved.

The invention relates to an acousto-optic integrated independent wireless gas detector system and an integrated control switch for controlling a solenoid valve linked with the gas detector, which mainly includes a first light emitting diode D1, a second light emitting diode D2, The third light-emitting diode D3, the first switch SW1, the second switch SW2, the third switch SW3, the zero-crossing detection circuit ZC, the first rectification and filtering circuit DC1, the second finishing and filtering circuit DC2, the first driving part DM1, the second driving Part DM2, first shield SH1, second shield SH2, first permanent magnet PM1, second permanent magnet PM2, first mesh plate MS1, second mesh plate MS2, third mesh plate MS3, fourth mesh plate Mesh plate MS4, notch, slider, square block, groove, support.

A power converting apparatus, includes: switching elements (S1 to S6) that are connected in parallel to a common bus bar and drive currents of different phases; and a motor controller (14) that controls the respective switching elements (S1 to S6). The motor controller (14) controls the respective switching elements (S1 to S6) in such a manner that a direction of a current fluctuation by an on / off operation of one switching element is opposite to a direction of a current fluctuation by an on / off operation of at least one of other switching elements.