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

The invention discloses a source electrode drive circuit and a controlling method thereof. The source electrode drive circuit comprises controlling transistors, a power supply capacitor and a current feed diode, wherein the controlling transistor are connected between the second end of a main switch pipe and the ground; the two ends of the power supply capacitor receive approximately constant bias voltage; the cathode of the current feed diode is connected to the control end of the main switch pipe; the anode of the current feed diode is connected with the second end of the main switch pipe; the controlling transistors are conducted and switched out periodically to enable the main switch pipe to be conducted and switched out correspondingly along the controlling transistors; the conducting time quantum of the main switch pipe comprises a first stage from starting in switching out state to completely conducting, and a second stage of being in completely conducting state; in the first stage, the controlling transistors provide approximately constant starting current. The source electrode drive circuit prolongs the conducting time of the main switch pipe, so as to restrain EMI greatly; meanwhile, time delay in switching out process of the main switch pipe is avoided, so as to reduce additional power consumption.

The invention relates to the technical filed of the multi-power-level high-voltage transducer, in particular to a five power-level transducer and the control method thereof. The five power-level of the invention is formed by connecting a high-voltage rectifier circuit, a high-voltage capacitor filter circuit, a voltage balancing circuit, and an inverting circuit in turn. The invention is characterized in that the inverting circuit adopts one or two apparatus/apparatuses in the IGBT and the IGCT to form an inverter, adopts a diode clamping five-power-level structure and three inverters with uniform bridge arms. The invention can provide higher resolution and can obtain better harmonic characteristic for the low-voltage area of a signal, better output characteristic and high-voltage high-power output for the high-voltage area of the signal; in addition, the invention has the advantages of easy control, and being safe and reliable.

The invention discloses a low-interference food processing machine, comprising a control circuit. The control circuit comprises a load for food processing, a load circuit for driving the load to work and a control chip. The load circuit comprises a switch which is a thyristor. The control chip controls the thyristor in a wave leaking way. The control chip controls the thyristor with a trigger pulse. A rising edge of the trigger pulse is at a zero-crossing point of power supply voltage. The trigger pulse maintains at the point of a minimum rate of change of the power supply voltage. The control chip can remove the trigger pulse at the minimum rate of change of the power supply voltage by adjusting the maintaining time of the thyristor trigger pulse, the interference brought by the thyristor trigger can thus be reduced, and the problem of magnetic interference of the resistive load is solved.

The invention discloses a double welding torch direct-current arc welding and power generation machine, which comprises a machine base, a rotating shaft, an electric brush device, a sliding ring as well as a main generator and a vice generator which have same number of poles, wherein the main generator has a first excitation regulation circuit with closed-loop automatic adjustment; and the vice generator has a second excitation regulation circuit with open-loop regulation. When the welding current of single torch is smaller than 50 percent of Ihm, double torches can be used simultaneously, thus improving the usage rate of welding machines and saving energy sources. When the current of the electric welding machines is greater than 50 percent of Ihm, output terminals of the two electric welding machines can be parallelly used.

The invention discloses a switch assembly. The switch assembly comprises a unit chain which is connected in series with an inductor. The unit chain comprises a plurality of half-bridge active clamping units which are successively connected in series. Each half-bridge active clamping unit has a conducting state and a clamping state. When all half-bridge active clamping units are in the conducting state, the switch assembly is closed. When all half-bridge active clamping units are in the clamping state, the switch assembly is open. By clamping or turning on the half-bridge active clamping units one by one, the voltage across both ends of the switch assembly rise or fall step-by-step, which reduces the device requirement of the switch assembly. The invention discloses a modular multi-level DC/DC converter. The switch assembly replaces a single-power device in a conventional DC/DC converter to acquire the modular multi-level DC/DC converter. The device requirement in the modular multi-level DC/DC converter is reduced. The invention discloses a modulation method and a clamping capacitor voltage balancing method.

The invention relates to the technical field of a multiple level high voltage transducer, in particular to a seven level high voltage transducer which is formed by mixing couplet components and a controlling method. The seven level high voltage transducer of the invention comprises a high voltage rectification circuit, a high voltage capacitance filtering circuit, an equalizer circuit and an inversing circuit which are connected in turn, which is characterized in that the inversing circuit is formed into an inverter through adopting one or two components of IGB and IGCT, adopting the inverter with the structure of diode clamping seven level structure, and three bridge arms of the inverter are same. The transducer of the invention can provide a higher differentiate ratio to a low voltage area of signals, obtain a better harmonious wave characteristic, and the transducer can obtain a better output characteristic to the high voltage area, also obtain a high voltage large power output, and simultaneously the transducer has simple control, safety and reliability.

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 provides a modulation method for phase shifts among bridge arms of an isolated modular multi-level DC-DC converter. According to the method, phase shift angles are introduced among various bridge arms of the modular multi-level DC-DC converter to generate a quasi two-level waveform of which the number of edge steps is 4N+1 on an AC side. The quasi two-level waveform with a greater number of steps is generated on the AC side, so that the voltage change ratio of the AC side is further reduced, electromagnetic interference is reduced, and meanwhile, the higher harmonic content of AC voltage and insulation impact on a transformer are relieved.

The invention discloses a three-level DC conversion circuit with controllable neutral point voltage and a control method thereof. The three-level DC conversion circuit of the present invention comprises a DC power supply, a first capacitor, a second capacitor, a first set of DC chopper circuit and a second set of DC chopper circuit; the first set of DC chopper circuit and the second set of DC chopper circuit are connected in parallel by three points of a positive voltage terminal, a negative voltage terminal and an intermediate voltage terminal, and an output positive terminal of the first setof DC chopper circuit and an output negative terminal of the second set of DC chopper circuit are connected in series with a load; and each of the first set of DC chopper circuit and the second set of DC chopper circuit comprises a plurality of switch tubes and a plurality of diodes. The three-level DC conversion circuit of the invention can constitute a plurality of control modes by controllingconduction of the switch tubes, thereby combining a plurality of timing sequence modes, so that four-quadrant voltage control operation of the load condition can be realized, and the purpose of controlling balance of the neutral point voltage of the three-level circuit can be achieved through mode switch.

The invention provides a middle-high voltage charging system control method based on a series digital voltage stabilizer, and belongs to the field of middle-high voltage electric vehicle charging stations. An output voltage of the series digital voltage stabilizer is controlled to be matched with a high-voltage cascade H-bridge module to form multi-level alternating current modulation voltage, theswitching frequency of the high-voltage cascaded H-bridge module is reduced, meanwhile, the size and inductance loss of a grid-side filter inductor are effectively reduced, and in cooperation with voltage stabilization control of a rear-stage DC/DC isolation stage of a digital series digital voltage stabilizer, voltage stabilization and balance of all modules of the system are guaranteed, so thesystem stably operates, and meanwhile system operation efficiency is improved.

The invention discloses a control system and method of a high-voltage inverter based on a DTC algorithm. The method includes the steps that S1, three-phase output voltages and currents output by the high-voltage inverter are obtained, and the stator flux linkage of a motor is calculated; S2, electromagnetic torque is calculated according to the stator flux linkage of the motor and stator currents; S3, closed-loop PID calculation is performed on speed setting and speed feedback of the motor to generate a torque signal; S4, the flux linkage sector, in a stationary coordinate system, of the stator flux linkage is obtained through calculation according to the stator flux linkage of the motor; S5, a switching vector is calculated according to output of a flux linkage hysteresis comparator, output of a torque hysteresis comparator and the flux linkage sector; S6, phase shifting is performed on power units of the high-voltage inverter according to the switching vector based on the DTC algorithm, so that corresponding PWM signals are generated. The electromagnetic torque can be rapidly and accurately controlled, and quick responses to sudden load increasing and decreasing are achieved.

The invention provides a method for forming a lithium ion battery with a mixed electrode. The active material of the mixed electrode includes lithium nickel cobalt manganate and lithium iron phosphate. The lithium nickel cobalt manganate is LiNi0.6Co0.1Mn0.3O2. The lithium iron phosphate is LiMg0.02Fe0.98PO4. The mass ratio of the lithium nickel cobalt manganate to the lithium iron phosphate is 75:25 to 80:20. The method includes performing charge-discharge cycles in a range of 3.55 to 3.65V and performing charge-discharge cycles in a range of 3.70 to 3.90V. The formation method of the presentinvention can fully activate the electrochemical activity of the active material of the mixed electrode, and improve the charge-discharge efficiency and durability of the electrode.

The invention relates to a negative voltage protection circuit. On one hand, a drain voltage control module disconnects a conductive path between a drain power supply and a drain of a power amplifier tube according to a first voltage, a second voltage and a drain switching signal, so that timely disconnection of the drain voltage can be realized through the first voltage, the second voltage and the drain switching signal; and on the other hand, when the received second voltage is changed into 0V, a voltage buffer module reduces the voltage change rate of an output sixth voltage, and finally, the time required for the drain electrode of the power amplifier tube to be powered off and the drain voltage to be reduced to be 0 is far shorter than the time required for the sixth voltage of the grid electrode of the power amplifier tube to be reduced to be 0, namely, when the drain electrode of the power amplifier tube is powered off and the drain 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 that the protection of the power amplifier tube is realized.