47results about How to "Reduce the rate of voltage change" patented technology

The present invention discloses a voltage sharing protection control circuit of series IGBT, and the structural feature is the setup of the voltage change rate control circuit and the terminal voltage clamp control circuit, wherein the voltage change rate control circuit is composed by a one-way conducting diode D2, a charge-discharge capacitance C1 and a resistance R2; during switch off time of the IGBT, the conducting diode D2 and the capacitance C1 in charged state constitute IGBT external capacitance parallel to CG end of the IGBT; during conducting time of the IGBT, the capacitance C1 takes resistance R2 as discharge path; the terminal voltage clamp circuit is composed by a triode T1 and T2, the clamp state is that DC passes through triode T2, diode D3 and charge grid capacitance of the IGBT. The present invention constitutes control circuit with simple analog elements, realizes IGBT switch voltage waveform similar to standard curve, and realizes different voltage change rate in different stages of the switch process.

A light unit cascade multi-level power converter comprises: an outputting transformer, a light unit, a central control system and a pump electrical source. The light unit comprises an unit power circuit, an unit electric source and an unit control system. The unit power circuit is connected to a group of sub-winding group of the multi-output transformer by three ends to output by two ends y1 and y2, and is connected to other light unit phase with the same phase. The unit power circuit has five structures, each structure has a plurality of structure style due to using different power devices. An electrical waveform at the light unit outputting side closes to sine. A pump power supply provides power for the central control system, the unit control system of the light unit and a driving power of the power device. The pump power supply outputs a high-frequency square wave alternating current which crosses each light unit and the control system through a high-voltage insulation cable, each light unit and the control system obtain a multi-way isolated low voltage direct current power supply by coupling magnetic loops insulative each other.

The invention discloses an indirect matrix transformation type multi-phase multi-level permanent magnet motor system. The indirect matrix transformation type multi-phase multi-level permanent magnet motor system includes a double-stator multi-phase composite permanent magnet synchronous motor, wherein two independent five-phase three-level inverters supplies power for stator winding ports of the motor respectively; an independent controllable rectifier supplies power for each five-phase three-level inverter; the two controllable rectifiers can share one set of LC filter at the power grid side; the LC filter includes a three-phase grid-connected inductor and a three-phase filter capacitor which is connected with the three-phase grid-connected inductor in parallel; and the first five-phase three-level inverter and the second five-phase three-level inverter are respectively connected with the two stator winding ports of the double-stator multi-phase composite permanent magnet synchronous motor. The invention also discloses a control method of the indirect matrix transformation type multi-phase multi-level permanent magnet motor system. The indirect matrix transformation type multi-phase multi-level permanent magnet motor system and the control method thereof can significantly improve reliability, power density, torque smoothness and operation efficiency of the motor driving system, and can lay the foundation of solving the technical difficulty that a high capacity motor traction driving system requires compact designs, reliable operation and energy-efficient aspects.

The invention discloses a converter for converting high-voltage direct current into alternating current in a high voltage direct current-light (HVDC-Light) system. The converter is characterized by comprising a direct current / direct current (DC / DC) input stage and a direct current / alternating current (DC / AC) inverting stage; the DC / DC input stage consists of a resonant soft switching converter; the secondary stage of a high-frequency transformer in the converter is provided with independent N*3 windings, the output voltage of each winding is subjected to rectification and capacitive energy storage, and N*3 mutually-isolated and equivalent independent direct current power supplies are formed; and the DC / AC inverting stage comprises N*3 power units, each power unit consists of a single-phase full-bridge inverter, the direct current input end of each power unit is connected to an independent direct current power supply, the alternating current output ends of N power units are sequentially connected in series to form an alternating current output phase of the converter, and three phases are connected into a three-phase alternating current output in a star-shaped (also called as Y-shaped) mode.

The invention discloses a driving circuit of a silicon-carbide semiconductor field-effect transistor. The driving circuit comprises a PWM control circuit, a driving signal amplifying circuit, an opening circuit, a turning-off circuit, a gate current-increasing circuit and a voltage change rate control circuit. With the gate current-increasing circuit, the driving current is increased during the opening process of the SiC MOSFET and the rising of the gate-source voltage of the SiC MOSFET is accelerated, so that the opening speed of the SiC MOSFET is increased. With the voltage change rate control circuit, the Miller capacitance between the SiC MOSFET drain and gate is enhanced and the SiC MOSFET drain-source voltage change rate is reduced, so that the current spike during opening of the SiCMOSFET is reduced. After the SiC MOSFET drain-source voltage does not change, a voltage control switch is turned off to avoid the SiC MOSFET false conduction caused by the crosstalk, so that the safeoperation of the SiC MOSFET is ensured.

Disclosed are a source driving circuit and a control method thereof. The source drive circuit includes: a control transistor, connected between the second terminal of the main switch tube and the ground; a power supply capacitor, the two ends of the power supply capacitor receive a substantially constant bias voltage; and a feed diode, the feed diode The cathode is connected to the control terminal of the main switch tube, and the anode is connected to the second terminal of the main switch tube, wherein the control transistor is periodically turned on and off, so that the main switch tube follows the control transistor and correspondingly conducts On and off, the conduction period of the main switch tube includes the first stage from the off state to the full conduction state and the second stage in the full conduction state, in the first stage, the The control transistor provides an approximately constant startup current. The source drive circuit prolongs the conduction time of the main switch tube, thereby advantageously suppressing EMI. At the same time, it also avoids the delay of the disconnection process of the main switch tube, thereby reducing the additional power consumption.

The present invention relates to a negative voltage protection circuit. On the one hand, the leakage voltage control module disconnects the conductive path between the drain power supply and the drain of the power amplifier tube according to the first voltage, the second voltage and the drain switch signal, so that through the first The first voltage, the second voltage and the drain switch signal can realize the timely disconnection of the drain voltage; on the other hand, when the received second voltage becomes 0V, the voltage buffer module reduces the voltage change of the output sixth voltage rate, and finally the drain of the power amplifier tube is powered off and the time required for the drain voltage drop to 0 is much shorter than the time required for the sixth voltage drop of the power amplifier tube grid to be 0, that is, the drain of the power amplifier tube is powered off to the drain During the period when the voltage becomes 0, the sixth voltage only changes by a small amount, and the grid voltage is always under the safe negative voltage protection, so as to realize the protection of the power amplifier tube.