104results about How to "Reduce turn-on loss" patented technology

The invention discloses an flyback converting circuit of source electrode drive comprising a starting circuit, an absorbing circuit, a transformer, a first switch MOS tube, a frequency generator, an output circuit, also comprising a second switch MOS tube in which the grid electrode is connected with the frequency generator, the source electrode is connected with the ground, the drain electrode is connected with the source electrode of the first switch MOS tube; a feedback circuit which is connected between the grid electrode and the source electrode of the first switch MOS tube; an assistant power circuit which is connected between the grid electrode of the first switch MOS tube and the ground. Because the first switch MOS tube uses the source electrode drive mode to realize soft starting and closing, the on-off process is transitied slowly, which can control the appearance of outburst short time sharp peak on current when opening the first switch MOS tube, thereby reducing the opening consume and improving the product efficiency, and the electric quantity in transformer leakage inductance at the moment of closing the first switch MOS tube is used, thereby improving the product frequency.

An active clamping positive-negative excitation converter of zero voltage switch is prepared as using active clamping circuit as converter primary edge circuit, parallel-connecting switch tube to converter primary edge winding then to two ends of input voltage, parallel-connecting clamp tube to clamp capacity then to said winding, using full-bridge rectification circuit as converter secondary edge circuit, series-connecting resonant inductance in secondary edge circuit to let current of secondary edge winding flow through inductance for making current variation of secondary edge winding be current variation of inductance excitation.

The invention discloses a super-wide output voltage range charger based on LLC topology and a control method. The super-wide output voltage range charger comprises an LLC resonant converter and a control circuit. The LLC resonant converter comprises a switch network composed of an MOSFET full-bridge conversion circuit, the input end of the switch network is connected with the input end of a power source, the output end of the switch network is connected with the input end of a resonant network, the output end of the resonant network is connected with a leakage inductor of a transformer, and a secondary side coil of the transformer is connected with a rectifying and filtering network; the control circuit comprises a control unit, the control unit controls MOS tubes of the MOSFET full-bridge conversion circuit to be connected or disconnected according to received signals at the input end and the output end of the LLC resonant converter, and therefore the LLC resonant converter can achieve no-voltage connection of a primary side switch tube and no-current disconnection of a secondary side rectifying diode within a full voltage range. The super-wide output voltage range charger is wide in output voltage, free of limitation of the input voltage range of a charged object and capable of charging various new energy electric vehicles.

The invention discloses a modulation method of a three-phase isolation type bidirectional direct-current converter under double PWM (pulse width modulation). The modulation method includes steps of 1) determining seven switch modes by adopting a PWM strategy according to the conditions that phase shift angle and duty ratio of corresponding drive signals on two sides of a three-phase transformer change to generate different voltage and current waveforms on two sides of the transformer; 2) calculating soft switching ranges corresponding to the switch modes; 3) calculating minimum current peak flowing through the three-phase transformer within the soft switching range of each switch mode; 4) comparing calculation results to obtain the situation that the current peak flowing through the three-phase transformer is minimum on the premise of soft switching within the integral power range; 5) giving output power and voltage transmission ratio and determining the switch modes and corresponding the duty ratio and the phase shift angle by judging the range where the output power and the voltage transmission ratio belong to. On the basis of soft switching, the current peak is minimum, switch loss of switching devices is reduced and efficiency of the converter is improved.

The invention discloses a segmented resistance type IGBT driving circuit, which is characterized in that a segmented resistor driving circuit comprises a plurality of segmented resistors which are connected in series, both ends of each segmented resistors are connected with a bypass MOS transistor in parallel; each bypass MOS transistor and a driving push-pull circuit are connected with a driving controller; and an IGBT gate clamping circuit comprises an IGBT gate voltage-stabilized clamping circuit and an IGBT gate power supply clamping circuit. The invention further discloses a control method of the segmented resistance type IGBT driving circuit, which is characterized in that a pulse rising edge and a falling edge are driven at the gate, and the size of the gate driving resistance is changed through switching of the bypass MOS transistors. The segmented resistance type IGBT driving circuit and the control method thereof can achieve the purposes of reducing the switching loss of an IGBT device and improving the application frequency of the device while ensuring suppression for surge and gate oscillation.

The invention relates to a high-power MOSFET driving circuit. PWM input signals pass through a hardware deadzone circuit, a pulse blocking circuit, an optical coupling isolation circuit and a peripheral circuit in sequence to generate the gate drive signals of the Mosfet of an upper bridge arm and the Mosfet of a lower bridge arm, the hardware deadzone circuit generates hardware deadzone time, the pulse blocking circuit is used for blocking pulse signals when a protection state occurs, the hardware deadzone circuit, the optical coupling isolation circuit, the peripheral circuit and a bootstrap circuit are combined to form the high-power MOSFET driving circuit used for driving the high-power Mosfets, and the measure of additionally installing the bootstrap circuit is taken to prevent the Mosfet gate-to-source voltage of the upper bridge arm from floating. The turn-on and turn-off speed of the Mosfets is improved, and therefore the turn-on and turn-off losses of the Mosfets are reduced. A blocking and judging circuit is used for blocking drive of hardware, and therefore the Mosfets are protected, the driving capacity of the driving circuit is improved, the work efficiency of the circuit is improved, and therefore cost is lowered.

The invention provides an X-ray high-voltage generator and a circuit and a method for controlling a series resonant converter. An inverter circuit of the series resonant converter comprises a leading leg and a lagging leg, the leading leg comprises a first switch device and a second switch device, and the lagging leg comprises a third switch device and a fourth switch device. The circuit comprises a driving circuit, and first driving signals, second driving signals, third driving signals and fourth driving signals can be provided to the first switch device, the second switch device, the third switch device and the fourth switch device by the driving circuit. Bipolar modulation can be carried out by the first driving signals and the second driving signals, turn-on moments of the third driving signals and the fourth driving signals are respectively identical to turn-on moments of the second driving signals and the first driving signals, and turn-off moments of the third driving signals and the fourth driving signals are determined according to currents of resonant cavities of the series resonant converter; alternately, bipolar modulation is carried out by the first driving signals and the third driving signals, turn-on moments of the second driving signals and the fourth driving signals are respectively identical to turn-on moments of the third driving signals and the first driving signals, and turn-off moments of the second driving signals and the fourth driving signals are determined according to the currents of the resonant cavities of the series resonant converter.

The invention discloses a full-range ZVS implementation method for a totem-pole PFC converter, and the method comprises the steps of obtaining an input AC voltage, an output DC bus voltage and a Boostinductive current of the totem-pole PFC converter through sampling, inputting the output DC bus voltage and a voltage reference in a PI regulator, obtaining a voltage loop output voltage, and determining a current reference signal; calculating an inductive current negative value, the extra conduction time, a main tube turn-off inductive current, and the first dead time and the second dead time required for realizing a full-range ZVS, controlling a main tube of the totem-pole PFC converter to be turned off according to the main tube turn-off inductive current, and determining the turn-off timeof each switching tube according to the first dead time and the second dead time; and determining the turn-on time of a rectifier tube of the totem-pole PFC converter according to the extra turn-on time, so that the totem-pole PFC converter realizes the full-range ZVS, and the working effect of the corresponding totem-pole PFC converter is improved.

A control method of a PFC circuit comprises that S1) an input voltage signal, an output bus voltage signal, an inductance instant current signal, an input voltage zero-crossing detection signal and aninductance current zero-crossing detection signal are sampled; S2) on the basis of the sampled input voltage signal, output bus voltage signal, inductance instant current signal, input voltage zero-crossing detection signal and inductance current zero-crossing detection signal, first, second and third MOS driving signals are generated; and S3) a first MOS of the PFC circuit is driven on the basisof the first and second MOS driving signals, and a second MOS of the PFC circuit is driven on the basis of the third MOS driving signal. The control method of the PFC circuit is easy to realize and can adapt to different PFC topologies.

The invention discloses a control circuit and a switching converter using the same. According to a technical scheme in embodiments of the invention, after a main power tube is turned off, a follow current switching tube is controlled to be turned on for a first time period; after the first time period is finished, the follow current switching tube is controlled to be turned on for a second time period within a preset time; therefore, the main power tube realizes parasitic parallel capacitor discharge through a discharge current before being turned on so as to realize zero-voltage conduction and effectively reduce conduction loss; and meanwhile, the follow current switching tube is turned on for a second time period at the resonance valley bottom of the drain-source voltage of the follow current switching tube, so the conduction loss of the follow current switching tube is also reduced, and system efficiency is improved.

The invention discloses a flyback active clamping circuit and a control method thereof. The flyback active clamping circuit comprises a flyback switch power supply, a first capacitor and a first switching tube. One terminal of the first capacitor is connected to a high potential terminal of an input power supply. The other terminal of the first capacitor is connected to the first terminal of the first switching tube. The second terminal of the second switching tube is connected to a common terminal of a main power switching tube and an primary side winding. A switching off moment of the firstswitching tube is adjusted according to conduction of the main power switching tube, switching off time of the first switching tube and voltage on two terminals of a magnetized inductor The flyback active clamping circuit and the control method thereof can reduce loss of turn-on of the main power switching tube and can reduce conduction loss.

The invention discloses a push-pull soft switching control circuit. The circuit comprises a push-pull control unit, a power MOS transistor driving unit, a push-pull boost power unit, an LC resonance unit, and an auxiliary power supply unit, the push-pull boost power unit comprises a tenth MOS transistor, an eleventh MOS transistor, a twelfth MOS transistor, a thirteenth MOS transistor, a fourteenth MOS transistor and a push-pull transformer, a drain electrode of the tenth MOS transistor and a drain electrode of the eleventh MOS transistor are both connected with one terminal of a primary coil of the push-pull transformer, a grid electrode of the tenth MOS transistor and a grid electrode of the eleventh MOs transistor are both connected with an output terminal of the power MOS transistor driving unit, a drain electrode of the twelfth MOS transistor and a drain electrode of the fourteenth MOS transistor are both connected with the other terminal of the primary coil of the push-pull transformer, and the LC resonance unit comprises a leakage inductor and a polypropylene capacitor. According to the circuit, the size of the power transformer can be reduced, the turn-on loss of a switching tube can be reduced, the loss of an inverter is reduced, the overall efficiency is improved, and the problem of EMI caused by hardware switching can be solved.

The invention provides a drive circuit for suppressing gate crosstalk and oscillation of a SiC MOSFET and belongs to the technical field of a power electronic switching device drive circuit. The technical scheme is characterized in that the drive circuit for suppressing gate crosstalk and oscillation of a SiC MOSFET comprises a push-pull circuit and a capacitor auxiliary circuit. The push-pull circuit and the capacitor auxiliary circuit are connected to a main circuit to form a complete working circuit. The main circuit is consists of two SiC MOSFET switch tubes connected to the same bridge arm up and down. The beneficial effects are that the drive circuit can effectively reduce the crosstalk voltage generated by the up and down two SiC MOSFET switch tubes on the same bridge arm without slowing down the on and off speed of the two SiC MOSFET switch tubes, and effectively reduce the oscillation of the driving output voltage of the two SiC MOSFET switch tubes in the on-off process.

The invention relates to a thyristor soft switch switching circuit of a static reactive power compensator and a control method. The thyristor soft switch switching circuit comprises a power grid, a thyristor control reactor TCR, a thyristor switching capacitor TSC and a control circuit, wherein the thyristor control reactor TCR and the thyristor switching capacitor TSC are connected in parallel and are then accessed to the power grid, and the control circuit comprises a phase detection module, a reactive detection and control amount calculation module, signal generators 1# and 2# and driving circuits 1-4. According to the thyristor soft switch switching circuit, thyristor TC and TL control on the TSC and the TCR is realized respectively through taking a power grid voltage phase as reference, and a period and a phase for TC and TL conduction triggering are determined according to magnitude of target control amount. The thyristor soft switch switching circuit does not includes an energy consumption resistor, a bridge diode rectification unit is additionally arranged, only one thyristor is employed for the TSC or the TCR, and bidirectional electric energy control can be realized.

The invention discloses an electromagnetic heating control method. The method comprises the following steps of collecting a voltage of a collecting electrode in IGBT to generate a collection voltage; carrying out differential processing on the collection voltage; comparing the collection voltage after the differential processing to a preset voltage to generate an open signal; and according to the open signal, controlling IGBT conduction. In the invention, the voltage of the collecting electrode in the IGBT only needs to be detected so that the IGBT is controlled to be opened at the lowest point of resonance; a mode of comparing two voltages in the correlation technology is replaced and open losses of the IGBT are effectively reduced. The invention also discloses an electromagnetic heating control apparatus and an electromagnetic heating apparatus comprising the electromagnetic heating control apparatus.

The invention relates to a groove type IGBT device capable of reducing Miller capacitance. The carrier concentration in the emitter side of an IGBT can be improved via a floated second conductive typearea, the junction depth of the floated second conductive type area is greater than the depth of a cellular groove, the floated second conductive type area wraps part of the bottom of the cellular groove to reduce the electric field in the corners of the cellular groove, and further withstand voltage of the IGBT device is improved. The floated second conductive type area is internally provided with one or multiple floated area grooves, the depth of each floated area groove is lower than the junction depth of the floated second conductive type area, the width of the floated area groove is notlower than that fo the cellular groove, and polycrystalline silicon in the floated area groove makes ohmic contact with metal of the emitter so as to shield voltage change of the cellular gate polycrystalline silicon and effectively reduce the Miller capacitance Cgc. Further, switching on is rapider, and the ON loss is reduced.

The invention provides a control circuit of a BUCK converter. The control circuit of the BUCK converter comprises a voltage comparison circuit and an on-off control circuit. The voltage comparison circuit compares a detection voltage with a preset voltage and outputs a comparison result to the on-off control circuit. The current value of the preset voltage can charge a junction capacitance voltageof a second switching tube Q2 of the BUCK converter to be larger than or equal to the input voltage of the BUCK converter. When the detection voltage is larger than or equal to the preset voltage, the on-off control circuit controls the second switching tube Q2 to be turned off, an inductor L current continues to charge the Q2 junction capacitor, and finally the voltage of the Q2 junction capacitor is equal to the input voltage Vin. When the voltage of the Q2 junction capacitor is equal to the input voltage Vin, the drain-source voltage of the Q1 is zero, the turn-on time of the next period of the Q1 is just reached, and the tube voltage of the Q1 is reduced to zero, so that the turn-on of the zero-point voltage reduces the turn-on loss, and the efficiency of the BUCK converter is improved.

The invention provides a power supply converter. The power supply converter comprises a transformer connected between a power supply input terminal and a power supply output terminal, a first switch is arranged between a primary winding of the transformer and a power supply input negative terminal, the on-off of the first switch is controlled via output signals of a first control circuit, and a branch circuit formed by the series connection of a capacitor and a diode is also connected between the primary winding of the transformer and the power supply input negative terminal. According to the power supply converter, high reverse voltage spike generated at two terminals of a switch tube during the turn-off of the switch tube can be reduced, and the switch loss is reduced.

The invention is suitable for the technical field of inverters, and provides a neutral-point active clamping three-level inverter, a control method and a control device. The neutral-point active clamping three-level inverter comprises a bridge arm unit, a clamping unit connected with the bridge arm unit, and a bridge arm output end connected with the bridge arm unit. The bridge arm unit comprisesa first switching tube, a second switching tube, a third switching tube and a fourth switching tube, and a first diode, a second diode, a third diode and a fourth diode which are in anti-parallel connection with the first switching tube, the second switching tube, the third switching tube and the fourth switching tube. The clamping unit comprises a fifth switching tube, a sixth switching tube, a fifth diode and a sixth diode, wherein the fifth diode and the sixth diode are connected with the fifth switching tube and the sixth switching tube in antiparallel. The fifth diode and the sixth diodeare silicon carbide diodes. Non-uniform heating of each switching tube can be reduced, and the electric energy conversion efficiency and stability are improved.

The invention discloses a driving circuit for driving a power switch device. The driving circuit comprises a first logic operation module, a second logic operation module, a main driving current module and an auxiliary driving current module; the first and second input ends of the first logic operation module are used for accessing a first control signal and a first bit selection signal; the inputend of the main driving current module is connected with the output end of the first logic operation module; the output end is used for connecting a grid electrode of the power switch device; the first and second input ends of the second logic operation module are used for accessing a second control signal and a second bit selection signal; the input end of the auxiliary driving current module isconnected with the output end of the second logic operation module, and the output end is used for connecting the grid electrode of the power switch device; the output current of the main driving current module and the auxiliary driving module commonly constructs the gate driving current of the power switch device, the precise and staged control on the gate driving current can be realized throughthe control on the output current of the main driving current module and the auxiliary driving module, and the device on-off speed is accelerated and the open loss is reduced under the condition of maintaining the current peak unchanged.

The invention provides a flyback conversion circuit, an on-off control circuit adaptive to the flyback conversion circuit and a valley bottom detection circuit and method. The valley bottom detection method comprises the step that when switching voltage resonance of the flyback conversion circuit is lowered to be equal to direct current input voltage of the flyback conversion circuit, a first time period is delayed, valley bottom detection signals are output and mark the current switching voltage resonance to the wave trough, and the duration of the first time period is one fourth of the resonant period of a primary winding and a primary equivalent resonant capacitance. By means of the technical scheme, the valley bottom detection precision of switching voltage can be improved.

The invention provides a triple phase shift control method and control device for a dual-active bridge circuit, and the dual-active bridge circuit comprises three-level plus three-level, three-level plus two-level, and two-level plus three-level. The method comprises the following steps: selecting a circuit structure according to the voltage ranges of an input voltage source and an output voltage source of the dual-active bridge circuit and the withstand voltage range of a switching tube; judging phase shift modes, including a step-down triple phase shift mode and a step-up triple phase shift mode; according to the equivalent voltage of the input voltage source, the equivalent voltage of the output voltage source and the closed-loop control quantity of the dual-active bridge circuit, calculating corresponding triple phase shift angles in different phase shift modes; and performing phase shift control according to the triple phase shift angle. According to the method, a proper dual-active bridge circuit topology is selected according to different voltage levels, the voltage withstand level of a switching tube is reduced, the combination mode is flexible, the cost is saved, triple phase shift control is adopted for the selected topology, the switching-on loss of the switching tube can be reduced, and the working efficiency of the dual-active full-bridge circuit is improved.