54results about How to "Suppress voltage spikes" patented technology

The invention relates to direct current (DC) step-up power conversion technology and discloses a current-type multi-resonance DC converter. The current-type multi-resonance DC converter comprises a square-wave current source generator, a multi-resonance network and a rectification filtering output unit which are sequentially connected in series, and is characterized in that: the multi-resonance network comprises a transformer, a parallel resonant inductor, a parallel resonant capacitor and a serial resonant inductor, wherein the serial resonant inductor is connected with a primary side of the transformer; the rectification filtering output unit comprises a diode rectifying circuit and a filtering capacitor which is connected with an output end of the diode rectifying circuit in parallel.

The invention relates to a flyback converter leakage inductance energy absorption feedback circuit of a photovoltaic grid-connected inverter, which comprises an absorption circuit and a feedback circuit; the input voltage of the photovoltaic grid-connected inverter is sequentially and electrically connected with the feedback circuit and the absorption circuit; the output end of the absorption circuit is connected with the primary winding of a high-frequency isolation transformer of the photovoltaic grid-connected inverter by a main power switch; the secondary winding of the high-frequency isolation transformer of the photovoltaic grid-connected inverter is connected with a inverting grid-connected circuit; the absorption circuit absorbs the leakage inductance energy of the high-frequency isolation transformer in the main circuit of the photovoltaic grid-connected inverter and the leakage inductance energy is fed back to the input end of the photovoltaic grid-connected inverter by the feedback circuit; simultaneously, the voltage of a clamping capacitance is regulated so that the voltage of the clamping capacitance follows the input voltage of the photovoltaic grid-connected inverter and the sum of the network voltage and the reflected voltage of the inverting grid-connected inverter so as to guarantee that the main inductance energy of the photovoltaic grid-connected inverter is not absorbed, simultaneously, restrains the voltage peak of the switch pipe of the main power and improves the efficiency of the flyback converter.

The invention discloses a drive circuit of a silicon carbide semiconductor field effect transistor. The drive circuit comprises a PWM control circuit, a drive signal amplification circuit, a turn-offcircuit, a gate shunt circuit and a current change rate control circuit, wherein the gate shunt circuit is switched on when the turn-off circuit works to perform shunt of the gate current of a SiC MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) and accelerate the switch-off of the SiC MOSFET; the SiC MOSFET is switched off when the drain-source voltage of the SiC MOSFET is increased toa preset value; the current change rate control circuit is switched off when the drain-source voltage of the SiC MOSFET is increased to the preset value to reduce the leakage current change rate. Thegate shunt circuit is arranged to perform shunt of the gate output current in the SiC MOSFET switch-off process and speed up the decreasing speed of the gate-source voltage so as to improve the switch-off speed of the SiC MOSFET; and besides, in the switch-off process of the SiC MOSFET, the switch-off of the current change rate control circuit reduces the leakage current change rate so as to reduce the voltage peak when the SiC MOSFET is switched off, the two circuits cooperatively act to achieve the voltage reduction speed and the low-voltage peak of the high gate-source voltage and ensure the safety operation of the SiC MOSFET.

This invention relates a reinforcement full bridge phase-shift soft-switch method and a converter used in power source or power system, including a full bridge phase-shift circuit made up from switchtubes and a primary side end inductor L1 serial-connected to the transformer. It is characterized by the said full bridge phase-shift circuit connecting to the voltage resonant network which enables delayed switch tubes to have the complete zero voltage when turned-on, and to suppress the peak voltage of output commutation diode. The voltage resonant network comprises connecting points parallel-connected to the transformer primaryside, inductory L1 connecting point, capacitor C1 at both ends of input voltage, diode D1 and capacitor C2 and diode D2 to form voltage resonance via inductor L1 serial-connected to the transformer primary side.

The invention discloses a voltage injection type SiC MOSFET active driving circuit. The voltage injection type SiC MOSFET active driving circuit includes a driving push-pull circuit, a driving resistor, a sampling circuit, a pulse generation circuit and a driving voltage compensation circuit, wherein the sampling circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor and a second capacitor, the pulse generation circuit comprises a first comparator, a second comparator and a first logic AND gate, and the driving voltage compensation circuitcomprises a fifth resistor, a sixth resistor, a first switch tube, a second switch tube and a first diode. According to the active driving circuit provided by the embodiment of the invention, the sampling circuit detects the driving pulse, so that the pulse generation circuit generates a compensation signal in the drain current drop stage in the SiC MOSFET turn-off process; Through the driving voltage compensation circuit, the gate voltage is compensated to raise the gate voltage and inhibit the change rate of the current so as to inhibit the voltage peak and oscillation at the two ends of the SiC MOSFET.

The invention discloses a power motor auxiliary gear shifting control system and method. A PI control unit is introduced in the gear shifting control system, and PI control over the rotation speed of a motor is carried out to solve the problem that the voltage surge caused by rapid speed adjustment of the motor in the gear shifting process is not taken into consideration in the prior art; due to the limitation of the whole gear shifting synchronization time, the power motor coupled with an input shaft of a gearbox needs to finish speed adjustment of about hundreds of turns within hundreds of milliseconds; and under the condition that the voltage of a battery end is high, the large voltage surge is caused by the instantaneous energy feedback of the battery end, overvoltage damage to an inverter is even caused, consequently gear shifting synchronization fails, tooth collision of the gearbox is caused, the gear shifting quality is affected and the service life of the gearbox and a battery is shortened. Therefore, the restraint on the voltage in the gear shifting speed adjusting process is an effective measure for guaranteeing reliable gear shifting and prolonging the service life of the gearbox and the battery.

The invention belongs to the technical field of high-frequency inverters, and particularly relates to a method for designing a low-stray inductance loop of a high-frequency inverter. A main busbar ofa converter loop is of a laminated structure and comprises two layers cooper bars including positive copper bars and negative copper bars, and the width, the length and the thickness of the positive copper bars and the negative copper bars are the same. The size specification of the main busbar under the expected inductance value is determined according to the width and length of the copper bars in the main busbar and the influence of the distance between the two layers of copper bars on the stray inductance of the main busbar. An absorption capacitor module is arranged on the main busbar andis used for inhibiting voltage spike caused by busbar inductance and reducing loop equivalent inductance. The absorption capacitor module comprises a plurality of small capacitors arranged in parallel, and the capacitance values of the small capacitors in the absorption capacitor module are determined through an equivalent circuit of the double-pulse test circuit. Based on the joint simulation ofQ3D and simplorer, the number of small capacitors in an absorption capacitor module is changed or the size specification of a main busbar is changed, so that a power loop conforming to the expected value of the final inductance is obtained.

The disclosed soft-switch power converter circuit comprises: a power switch, an output rectifying diode connecting with former switch, and a buffer circuit between last two parts, wherein the rectifying diode comprises: a first/second buffer diode serial connecting between the switch and output end, a buffer inductor between the output diode and output end to inhibit the reverse recovery current, a first buffer capacitor set between former two connecting nodes, and a second buffer capacitor paralleled between two ends of the first buffer diode to inhibit the voltage peak during switching. This invention simplifies the entire structure.

The invention provides a novel lossless clamping network of a primary side feedback flyback converter and a design method. The novel lossless clamping network comprises capacitors C11 and C12, an inductor L, diodes D11 and D12, and a voltage stabilizing diode Dz, and is composed of three branches, namely a branch formed by connecting the capacitors C11 and C12 in parallel, a branch of the diode D11 and a branch formed by connecting the diode D12 and the inductor L in series. According to the invention, double capacitors with different capacities are connected in parallel, the large capacitor C12 effectively suppresses voltage overshoot and achieves the clamping function, and the small capacitor C11 improves the response speed; according to different properties of branches, the clamping network is composed of three branches: a capacitor C11 and a capacitor C12 are connected in parallel, so that the response speed is improved, and the voltage peak in the switching-off process of a switching tube is suppressed; the branch of the diode D11 is conducted in the switching-off process of the switching tube, so that a channel is provided for transferring leakage inductance energy to the clamping network; and the diode D12 and the inductor L are connected in series to form a branch, and the capacitor is fed back to store energy in an LC resonance mode in the switching-on process of the switching tube, so that partial drain current of the switching tube is formed.

The invention discloses a multi-resonant network unit isolated high-gain DC converter comprising an input power supply Vg, a first switching tube S1, an active clamping circuit, a multi-winding transformer T, an output capacitor Co, an output diode Do and a load R. The multi-winding transformer T comprises a primary winding Tp and multiple secondary windings Tk, wherein k is a positive integer. The active clamping circuit comprises a first capacitor Cr, a second switching tube S2 and a resonant inductor Lr. The multi-resonant network unit isolated high-gain DC converter also comprises quasi voltage multiplying structures. The quasi voltage multiplying structures comprise quasi voltage multiplying capacitors Ck and quasi voltage multiplying diodes Dk. The switching logic of the first switching tube S1 and the second switching tube S2 is complementary connection. The multi-resonant network unit isolated high-gain DC converter has the advantages that the structure is simple, the number ofthe switching tubes is less, the voltage stress of the diodes can be reduced, zero current disconnection of the diodes can be realized and the turn ratio of the transformer can be reduced; zero voltage connection of the primary switching tube can be realized and the voltage stress can be reduced; and soft switching of the power tubes can be realized and the switching loss and the EMI interferencecan be reduced.

The invention discloses a push-pull converter. The push-pull converter comprises a transformer and two switch tubes. The first ends of the two switch tubes are connected to the two ends of a primary side winding of the transformer respectively, and the second ends of the two switch tubes share a common ground. The push-pull converter further comprises a columnar high-frequency inductor and a high-frequency thin-film capacitor, wherein the first end of the columnar high-frequency inductor is connected with the positive end of an input power, and the negative end of the input power is grounded; the second end of the columnar high-frequency inductor is connected with a center tap of the primary side winding of the transformer; and the high-frequency thin-film capacitor is connected between the second end of the columnar high-frequency inductor and the ground. With the application of the technical scheme of the invention, voltage spike generated at the starting instant of the switch tubes can be suppressed; besides, the push-pull converter is simple and effective, and high in applicability.

The invention relates to the field of power conversion of power electronics, in particular to a high-efficiency DC/DC converter which comprises a power conversion circuit, a controller and a buffer circuit. The buffer circuit is arranged between an input end and the power conversion circuit, the controller is connected with the power conversion circuit, the power conversion circuit comprises a switching tube and an LC oscillation circuit, and the buffer circuit is used for slowing down the rising speed of the voltages at the two ends of a source electrode and a drain electrode of the switchingtube. According to the invention, the voltage spike when the switching tube is turned off can be suppressed, thereby avoiding a breakdown phenomenon.

The invention discloses three-phase single-phase high-frequency link matrix PET topology and modulation, which belong to the technical field of power electronic power converter topology and modulation. The topology is formed by connecting a three-phase alternating current power supply, an input L filter, a pre-stage matrix converter, a high-frequency transformer, a backward-stage matrix converter,an output LfCf filter and a load. Magnetic coupling and power transmission are performed by adopting a high-frequency transformer, conversion of output voltage and frequency is realized by using a voltage type circuit topology, and a decoupling modulation strategy of combining discrete SVPWM of a pre-stage circuit and discrete SPWM of a post-stage circuit of the transformer in a double-frequencyphase locking mode is adopted, so that a bidirectional switch of the matrix converter reasonably works. Safe current conversion of the matrix converter is realized by adopting a discrete control modeas a whole, and voltage spikes generated by existence of leakage inductance of the transformer are effectively suppressed.

The embodiment of the invention discloses a driving circuit of a synchronous rectification device. The driving circuit comprises a controllable charging circuit and a slope detection circuit. The slope detection circuit is used for sensing whether the potential difference of a detection end of the driving circuit relative to a reference ground end of the driving circuit rises suddenly or not, andproviding a slope detection signal in response to the rising abrupt change edge of the potential difference so as to make the controllable charging circuit form a current path from the detection end to a power supply end and provide a charging current for the power supply end when the rising abrupt change edge of the potential difference occurs. According to the embodiment of the invention, the driving circuit can make the controllable charging circuit convert overshoot voltage spike energy generated in the rising abrupt change of the potential difference into the power supply potential of thewhole driving circuit when the potential difference of the detection end relative to the reference ground end rises and changes suddenly each time, so that the voltage spike be suppressed, the voltage spike energy is reasonably absorbed, converted and utilized, and the overall efficiency of the system is improved.

The invention relates to a single-phase high-frequency link matrix inverter and a modulation method. A positive electrode of a direct current power supply DC of the inverter is connected with drain electrodes of a first MOSFET tube and a third MOSFET tube and a negative electrode of a first diode respectively; the negative electrode of the direct-current power supply DC is connected with the source electrodes of the second MOSFET, the fourth MOSFET and the positive electrode of the second diode; the first end of a primary coil of a transformer circuit is connected with the source electrode of the first MOSFET and the drain electrode of the second MOSFET; the second end of the primary coil of the transformer circuit is respectively connected with the anode of the first diode and the cathode of the second diode; the third end of the primary coil of the transformer circuit is respectively connected with the source electrode of the third MOSFET and the drain electrode of the fourth MOSFET; and the secondary coil of the transformer circuit, the post-stage matrix converter, the output filter and the load form a closed circuit in sequence. According to the invention, the pre-stage ZVZCS form soft switching is realized, and the capacitance oscillation on a post-stage switching tube is reduced.

Disclosed are an energy recovery circuit for isolating a voltage converter and a method thereof. The energy recovery circuit includes: an auxiliary switch tube and a recovery control circuit. The auxiliary switch tube is coupled in series with the clamping capacitor to form a first circuit branch. The first circuit branch is coupled in parallel with a primary winding, or coupled in parallel with the primary switch tube. The recovery control circuit provides the control signal of the auxiliary switch tube. The auxiliary switch tube is turned on during the charging process of the clamp capacitor, and the auxiliary switch tube is turned off when the subsequent discharge process of the clamp capacitor ends. The charging process of the clamp capacitor is monitored according to the auxiliary switch voltage signal and the auxiliary switch current signal.

The invention discloses an isolation matrix converter and a control method. The converter comprises a bidirectional switch module, a transformer, a resonant inductor, a resonant capacitor and a bridge arm capacitor. The bidirectional switch modules and the bridge arm capacitors are connected in series to form bridge arms of the converter, and each bridge arm of the converter comprises at least one bidirectional switch module; a primary winding of the transformer is connected in series with the resonant inductor and the resonant capacitor and then connected with two ends of a bridge arm of the converter; the bidirectional switch module comprises a clamping capacitor and a bidirectional switch unit. The bidirectional switch unit forms two bridge arms of the module, and the two ends of the clamping capacitor are connected with the two ends of the two bridge arms of the module; the clamping capacitor and the two upper bridge arms or the two lower bridge arms of the two bridge arms form a clamping absorption circuit; the bidirectional switch unit comprises at least two controllable switch tubes; the clamping capacitor suppresses a voltage peak generated when a switching tube in the bidirectional switch module acts. Therefore, the switch tube is protected, the safety of the whole converter is protected, and the reliability of the whole converter is improved.

The invention belongs to the technical field of voltage reduction circuit design, and particularly relates to a voltage reduction circuit. The voltage reduction circuit comprises an MOS transistor with the drain electrode connected with the positive electrode of an input power supply, a filter inductor with one end serving as the first end thereof and connected with the source electrode of the MOStransistor and the other end serving as the second end thereof and the output positive electrode of the voltage reduction circuit, a filter capacitor with one end serving as the first end thereof andconnected with the second end of the filter inductor and the other end serving as the second end thereof and the output negative electrode of the voltage reduction circuit, a first diode with the negative electrode connected with the source electrode of the MOS transistor, a second diode with the negative electrode connected with the positive electrode of the first diode and the positive electrode connected with the negative electrode of the input power supply, and a first capacitor with one end connected with the drain electrode of the MOS transistor and the other end connected with the positive electrode of the first diode.