38results about How to "Suppress reverse recovery issues" patented technology

The invention discloses a soft-switch three-phase PWM (Pulse Width Modulation) rectifier with an auxiliary free-wheel channel. The soft-switch three-phase PWM rectifier comprises a three-phase bridge arm consisting of 6 total-control main switches respectively provided with antiparallel diodes and parallel capacitors, input filtering inductors connected between the middle points of each phase of bridge arm and an AC power grid, and an output capacitor connected to the output terminal of the three-phase bridge arm, wherein the total-control switches with both the antiparallel diodes and the parallel capacitors are connected or not connected to two ends of the three-phase bridge arm; an auxiliary switch with both antiparallel diodes and parallel capacitors is connected between a DC bus and the output capacitor of the three-phase bridge arm; and resonance branch circuits consisting of both resonance inductors and clamping capacitors are connected to two ends of the auxiliary switch in a bridging manner. The soft-switch three-phase PWM rectifier has a simple structure, and can inhibit reverse restoration of diodes and reduce electromagnetic interference. All switch devices of the rectifier achieve zero-voltage switch-on, have small loss and high circuit efficiency, facilitate improving the operating frequency and further improve the power density. The rectifier provided by the invention realizes output capacity and voltage control and achieves the power factor correction function of input current.

The invention discloses a zero voltage switch modulation method of a three-phase four-wire system zero voltage switch inverter. The zero voltage switch modulation method of a three-phase four-wire system zero voltage switch inverter includes the steps: comparing a three phase main switch modulated wave of a three-phase four-wire system zero voltage switch inverter with a sawtooth carrier wave; generating a main switch signal through an inverter and a rising edge time-delay module; comparing an auxiliary switch modulated wave of the three-phase four-wire system zero voltage switch inverter with the sawtooth carrier wave; generating a leg straight-through signal and an auxiliary switch signal through the rising edge time-delay module, the inverter and a falling edge time-delay module; and applying the effect of the straight-through signal to a full control main switch during the commutation process of the full control main switch of the three-phase four-wire system zero voltage switch inverter to supply a freewheeling loop for magnetizing of a resonant inductor so as to store enough resonant energy. The zero voltage switch modulation method of a three-phase four-wire system zero voltage switch inverter is simple in structure, and can realize full range soft switching in the power frequency period. Besides, all the switching devices can realize zero voltage switching so that the zero voltage switch modulation method of a three-phase four-wire system zero voltage switch inverter has low switching loss and high circuit efficiency, and can restrict reverse recovery of a diode and reduce electromagnetic interference.

The invention discloses a one-phase inverter modulation method including: subjecting modulating waves to full-wave rectification, comparing the rectified modulating waves with sawtooth carrier waves, generating bridge arm shoot-through signals and auxiliary switching signals by means of rising edge delay and rising edge detection, acting the shoot-through signals on a master switch during current conversion of the master switch, and supplying a follow current circuit to magnetizing of a resonant inductor so as to supply sufficient resonant energy. The one-phase inverter modulation method is simple in structure and capable of realizing full-range soft switching within a power frequency period, all switching devices realize zero voltage switching, switching loss is low, circuit efficiency is high, reverse recovery of diodes can be inhibited, and electromagnetic interference is reduced.

The converter includes six pieces of three phase bridge arm including full controlled main switch with diode connected in inverted parallel, input inductance connected between power source and middle point of each phase bridge arm, and output capacitance connected to output end of three phase bridge arm. Characters are that capacitance is connected to six main switches respectively. Resonant inductance is connected to DC bus of three-phase bridge arm and output capacitance. Cascaded circuit of auxiliary switch and clamping capacitance is cross-connected on two ends of resonant inductance. Two ends of the auxiliary switch are connected to diode in inverted parallel as well as connected to capacitance. Features of the converter are simple structure, restraining backward recovery of diode connected in inverted parallel, realization of soft switch and high efficiency of circuit.

The invention discloses a low-additional-voltage zero-voltage switch energy storage bridge type inverter and a modulation method. The low-additional-voltage zero-voltage switch energy storage bridge type inverter comprises a direct-current side storage battery, a direct-current capacitor, an alternating-current filter inductor and a single-phase bridge arm, wherein the single phase bridge arm is formed by four full-control master switches with anti-parallel diodes, a series branch of an auxiliary switch with an anti-parallel diode and a clamping capacitor is connected between the direct-current side storage battery and a direct-current bus of the single-phase bridge arm, two ends of the branch are connected with resonance inductors, and two ends of the master switches and the auxiliary switch are in parallel connection with the capacitor. The low-additional-voltage zero-voltage switch energy storage bridge type inverter can independently run with load or runs in a grid-connection mode and is simple in structure, power can flow bidirectionally to charge and discharge the storage battery, the master switch uses a sine wave pulse width modulation method, and modulation signals of the master switches are synchronous with the auxiliary switch. In one switching period, the auxiliary switch only works once to enable all master switches to achieve zero-voltage switching. Reverse recovery current of the anti-parallel diodes of the master switches can be restrained so as to be small in switching loss, high in circuit efficiency and favorable for improving efficiency to improve power density.

The invention provides an additional-voltage-free zero voltage switch energy-storing semi-bridge type inverter and a modulation method. The inverter comprises a direct current side storage battery, a direct current side voltage division capacitor, an alternating current side filtering inductor and a single-phase bridge arm formed by two full control main switches with antiparallel diodes. An auxiliary switch of the antiparallel diodes is connected between direct current buses of the voltage division capacitor and the single-phase bridge arm. Capacitors are connected at two ends of the main switches and the auxiliary switch, and a resonant branch formed by connecting a resonant inductor and a clamping capacitor is connected at two ends of the auxiliary switch in bridge mode. The inverter runs independently with load or in grid-connection mode. The main switches adopt a sine wave pulse width modulation method, and modulation signals of the auxiliary switch are synchronous with modulation signals of the main switches. In each on-off period, the auxiliary switch can achieve zero voltage opening of the main switches by simply acting once, reverse current restoring of the antiparallel diodes of the main switches is restrained, and the switch voltage stress is equal to the direct current side voltage of the inverter. The inverter is small in switch consumption, high in circuit efficiency and favorable for improving working efficiency and further improves power density.

The invention discloses a zero-voltage switch modulation method of a three-phase four-wire system zero-voltage switch inverter. The modulation method compares the three-phase main switch modulation wave of the three-phase four-wire zero-voltage switching inverter with the sawtooth carrier, and then generates the main switch signal through the inverter and the rising edge delay module, and converts the three-phase four-wire zero-voltage switching The auxiliary switch modulation wave of the voltage switch inverter is compared with the sawtooth carrier, and then the bridge arm through signal and the auxiliary switch signal are generated by the rising edge delay module, the inverter and the falling edge delay module. In the three-phase four-wire zero voltage switch During the commutation period of the fully-controlled main switch of the inverter, the through signal is applied to the fully-controlled main switch to provide a freewheeling circuit for the magnetization of the resonant inductor to store sufficient resonance energy. The invention has a simple structure, can realize full-range soft switching in the power frequency cycle, realizes zero-voltage turn-on of all switching devices, has small switching loss, high circuit efficiency, can suppress reverse recovery of diodes, and reduces electromagnetic interference.

The invention relates to a power factor correction converter based on a magnetic coupling lossless buffer circuit, comprising a rectifier bridge and a boosted circuit, wherein the boosted circuit comprises a boosted inductor with an auxiliary coupling winding and a buffer network; one end of the boosted inductor is connected with a rectifier bridge common cathode, the other end of the boosted inductor is connected with one end of the coupling winding, and the other end of the coupling winding is connected with a first diode anode; a main switch and a buffer inductor are connected among the boosted inductor, a coupling winding contact and a rectifier bridge common anode, and the buffer inductor and a main switch contact are connected with a second diode anode; a buffer capacitor and a third diode are connected among the coupling winding, a first diode contact and the rectifier bridge common anode, and the buffer capacitor and a third diode cathode contact are connected with a fourth diode anode. The invention can suppress the reverse recovery of the diodes, reduce the switching loss and improve the conversion efficiency; the auxiliary coupling winding is used for resetting the electric current of the buffer inductor; and the buffer capacitor is used for absorbing the energy reversely recovered by the diodes and transmitting the energy into an output capacitor, therefore, the lossless buffering is realized.

The invention discloses a method for modulating a three-phase four-wire soft-switching rectifier having an equalizing function. The method comprises the steps of: fixing the switching frequencies of all main switching tubes and auxiliary switching tubes, and enabling the switching frequencies to be same; in each switching period, performing synchronization at the time of conversion from a diode toan complementary switching tube in four groups of bridge arms, turning off the auxiliary switching tube S<aux> before the synchronization time, and resonating the bus voltage at two ends of the fourgroups of bridge arms to zero; after conversion processes from all diodes to a main tube are ended, increasing a bridge arm through process according to the polarity of balanced inductive current, and, when the balanced inductive current outflows the midpoint of the fourth group of bridge arms, not increasing the bridge arm through process; and, when the balanced inductive current flows into the midpoint of the fourth group of bridge arms, increasing the bridge arm through process, and, after resonating the voltage on a resonant capacitor C<raux> to zero, performing zero-voltage switching of the auxiliary switching tube S<aux>. By means of the method in the invention, the reverse recovery current of a main switch anti-parallel diode can be effectively inhibited; the switching loss is low;and the efficiency and the power density are easily increased.

The invention discloses a non-unity power factor output space vector modulation method of a three-phase soft-switching converter. In each space vector sector, through the vector modulation method of the present invention, it can be ensured that in any switching cycle, all the diodes of the converter commutate to the main switching tube on the opposite side synchronously, so that the auxiliary switching tube can Only one action is needed to realize zero-voltage turn-on of all switching tubes. The invention solves the modulation problem of the three-phase soft-switching converter under the output of non-unity power factor, the number of switching actions is small, all the switching tubes are turned on at zero voltage, the circuit conversion efficiency is high, and it is beneficial to expand the three-phase soft-switching converter The scope of application of the device.

The embodiment of the invention discloses a bridge arm used in a motor drive circuit and a control method thereof, which relate to the technical field of electrical equipment and electrical engineering, and can suppress the reverse recovery problem of the MOSFET body diode of the motor bridge arm under the condition of high current, and reduce the power consumption of the motor. Drive circuit loss, improve system efficiency. The invention comprises: bridge arm switch tube, bridge arm optimized switch tube, reverse series switch tube, reverse parallel diode, driver and delay link. Wherein, the reverse series switch tube can be connected in series with the switch tube of the upper bridge arm, or can be connected in series with the switch tube of the lower bridge arm, and can also be optimized to reduce the switching loss of the upper and lower bridge arms simultaneously by using two reverse series switch tubes. The anti-parallel diode is connected in parallel to the bridge arm with the anti-series switch. The invention is suitable for the reverse recovery suppression of the bridge arm of the motor.