46results about How to "Reduce the rate of change of current" patented technology

The invention discloses a high-power insulated gate bipolar translator (IGBT) drive protection circuit applied to wind power generation, which comprises a power circuit (1), a driving circuit (2) and an overcurrent protection circuit (3), wherein the power circuit (1) is connected with the driving circuit (2) and the overcurrent protection circuit (3) and outputs positive and negative bias voltage to connect and disconnect the IGBT (4); the driving circuit (2) outputs a driving signal to the grid of the IGBT (4) and controls the connection and disconnection of the IGBT (4); and the overcurrent protection circuit (3) is connected with a collector and an emitter of the IGBT (4), judges whether the IGBT (4) is overcurrent by detecting voltage between the collector and the emitter, controls adriving point of the driving circuit under the overcurrent condition, controls the disconnection of the IGBT (4), and transmits a fault signal through a pulse transformer in the power circuit (1).

The invention provides an insulated gate bipolar transistor (IGBT) protection circuit and a motor control system, belonging to the filed of the motor control. The IGBT protection circuit comprises a sampling circuit, a feeding back circuit, a driving circuit and a slow turn-off circuit. The IGBT protection circuit adopts the slow turn-off circuit, thus the turn-off time of the IGBT is prolonged, the current change rate is reduced and the IGBT is protected against damage when the IGBT carries out the over-current protection.

The invention relates to a zero-voltage switching quasi-resonance high-gain DC boost converter. An LC resonance circuit is added at the rear ends of main switches S1 and S2 and the front end of an output load of an improved boost DC converter under a hard switching condition, thus, a soft switching condition is formed, the switching environment of circuits in which devices are positioned is improved, and voltage and current change rates during the switching process are slowed via resonance; voltages at both ends of each of the main switches S1 and S2 are reduced to zero before the main switches S1 and S2 are switched on, so that the switching loss and switching noise are reduced; circuit efficiency under the soft switching condition is high when comparing input / output power under the hard switching condition in the prior art and under the soft switching condition provided by the invention; the circuit topological structure is simple; and the zero-voltage switching quasi-resonance high-gain DC boost converter can satisfy requirements of being simple and efficient, light in weight and low in noise when compared with the improved boost DC converter under the hard switching condition in the prior art.

The invention provides an on-chip switch step-by-step control circuit and method and an on-chip signal pin drive circuit. The on-chip switch step-by-step control circuit at least comprises a switch tube module, a control end drive module and a delay chain; the switch tube module at least comprises n stages of switch tubes connected in parallel, the control end drive module at least comprises n stages of drivers, the output end of each driver is connected with the control end of the corresponding switch tube to be used for driving the corresponding switch tube, and the delay chain at least comprises n-1 stages of delay modules in series, wherein the input end of the first stage of delay module and the input end of the first stage of driver are jointly connected into a control logic input signal, and the output end of the (n-1)th stage of delay module is connected with the input end of the nth driver. By means of the on-chip switch step-by-step control circuit, the current change rate can be effectively reduced; in addition, on the premise that the current change rate is equally reduced, the shortest closing or opening process is achieved, and the switching speed can be maximized.

The invention relates to a switch-free switching auto-passing neutral section device for the electric railway, which is characterized in that high voltage large resistance electric resistance Rs are connected in series among a power supply arm U and a power supply arm D of any output phase alpha and beta of a three-phase-two-phase transformer T of a traction substation and a contact network neutral section M1 at the exit of the traction substation; the high voltage large resistance electric resistance Rs are also connected in series between ends of the power supply arm U and D of the traction substation and the contact network neutral section M2.The auto-passing neutral section device dispenses with a high voltage switch or a breaker, avoids transient overvoltage due to frequent switching, realizes safe and reliable auto-passing neutral section of an electric locomotive and saves operation costs and maintenance fees.

The invention discloses an active discharge system of a motor controller. The active discharge system comprises a control module, a plurality of driving modules, an upper bridge driving power supply module and a lower bridge driving power supply module, wherein the driving modules are connected with the control module and semiconductor switches in corresponding bridge arms; the upper bridge driving power supply module is connected with the driving modules corresponding to all upper bridge arms; the lower bridge driving power supply module is connected with the control module and the driving modules corresponding to all lower bridge arms; and when the control module needs to perform active discharge, the driving modules corresponding to the upper bridge arms are triggered to drive the semiconductor switches in the upper bridge arms to enter straight-through states, the lower bridge driving power supply module is triggered to lower output voltages output to the driving modules corresponding to the lower bridge arms at the same time in order that the semiconductor switches in the lower bridge arms enter a linear region, and the driving modules corresponding to the lower bridge arms are triggered to drive the semiconductor switches in corresponding lower bridge arms to enter short-term on-off states. Through adoption of the active discharge system, cost is lowered, and voltage and current change rates of the semiconductor switches of the lower bridge arms in an active discharge process can be reduced.

The invention discloses a low-noise and high-ground-up-noise-resistant output driving circuit and method. The circuit is divided into a pre-driving module, a PMOS driving module and an NMOS driving module, the PMOS driving module and the pre-driving module are connected to a PMOS input node, and the NMOS driving module and the pre-driving module are connected to an NMOS input node, so that outputdriving resistance of the output driving circuit is dynamically adjusted so as to reduce the ground-up noise when a dynamic signal is input at the PMOS input node or the NMOS input node; and the output driving resistance is improved to enhance the high ground-up noise resistant effect when a static signal is input at the PMOS input node or the NMOS input node. Compared with the prior art, the output driving resistance of the output driving circuit is dynamically adjusted, so as to reduce the ground-up noise; meanwhile, the output resistance is improved when in static driving, so as to improvethe high ground-up noise effect resistance.

The invention provides a semiconductor device and a power converter using it. The prior arts have the problems that: conventional freewheeling diode with PN junction having a short service life is used in power converter, the forward voltage and the conduction loss are all large; in addition, the reverse recovery current and switch loss are large in reverse recovery process; thereby the loss of the power converter is large. In the invention, when the current flows forward, it is caused to flow to the pn diode with low forward voltage; and in reverse recovery process, the reverse recovery current is caused to flow to the Schottky diode with small reverse recovery current. In addition, the device of the invention has a pn diode / Schottky diode switching unit. By reducing the forward voltage of the freewheeling diode and reducing the reverse recovery loss, the invention can provide a semiconductor device with less loss and a power converter using it.

The invention discloses a hysteresis current control method of a single-phase parallel type active power filter. The switch on / off of the APF is commonly decided by three variables: APF output current, current error and power grid voltage; through the reduction of current change rage dic / dit, the reduction of current error theta and the reduction of APF output current distortion degree, the switches at a left bridge arm and a right bridge arm of the single-phase APF alternatively work in the positive / negative half cycle of the power grid voltage, and the switch loss of the APF power device is less. The method is equally suitable for the current tracking control of the APF in three-phase four-wire system, and is good in feasibility and practical value.

The invention provides a piezoelectric crystal fuel injector driving circuit. On the basis of MC33816, IRS2101 is used for improving the maximum driving voltage capacity of the MC33816, and meanwhile, the functions of hardware current closed loop / fault protection and the like of the MC33816 are used for achieving driving of a piezoelectric crystal fuel injector; an inductor L is connected in series in a charge-discharge loop of a piezoelectric crystal; due to the energy storage effect of the inductor, energy can be transferred to a capacitor through the inductor in the charge-discharge process, so that the current change rate is reduced; and when the current change rate is reduced, the current control precision is correspondingly improved, the MOS control frequency is reduced, and the circuit reliability is improved.

The invention discloses a SiC MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) self-adaptive driving circuit and a self-adaptive driving method. An embedded system inputs PWM, the PWM1 and the PWM2 are output; the PWM1 and the PWM2 are respectively and correspondingly connected with the base electrodes of the NPN tube and the PNP tube through an isolation amplifying circuit; collector electrodes of the NPN transistor and the PNP transistor are correspondingly connected with a positive electrode end and a negative electrode end of a power supply respectively, emitting electrodes of the NPN transistor and the PNP transistor are connected with gate electrodes of the SiC MOSFETs, and source electrodes of the SiC MOSFETs are grounded. Respectively obtaining a current change rate and avoltage change rate of a drain electrode of the SiC MOSFET through the isolation sampling circuit and the differentiating circuit; wherein the embedded system is used for controlling the voltage of the drain electrode of the SiC MOSFET according to the level of PWM and the current change rate and the voltage change rate of the drain electrode of the SiC MOSFET; and the pulse widths of the PWM1 and the PWM2 are adjusted in real time, so that the peak current or surge voltage generated in the switching process of the SiC MOSFET is effectively adjusted and controlled, and the self-adaptive quickon-off operation of the SiC MOSFET is realized.

The invention discloses a state observation based IGBT turn-off voltage peak inhibition system and control method. The method comprises the following steps that a controller reads a bus voltage valueVdc and an output current value Ic of an IGBT module within a switching period; the read bus voltage value Vdc and the output current value Ic of an IGBT module within the switching period are analyzed, and a turn-off control instruction is output to a drive board; a multi-level turn-off circuit adds one level of voltage to a gate electrode signal of the IGBT module in the turn-off process, and the drive board adjusts the duration of a voltage Vm of the multi-level turn-off circuit according to the received turn-off control instruction; and the turn-off voltage peak of the IGBT module inhibited via the process in which the multi-level turn-off circuit changes the gate electrode of the IGBT module. According to the IGBT state after observation, the multi-level turn-off circuit is adjusted,the inhibition effect of the IGBT turn-off voltage peak is improved, and the total turn-off delay time and total turn-off loss of the IGBT are reduced effectively.

The invention provides a switch parallel connection dynamic current sharing circuit based on negative coupling mutual inductors. the circuit comprises n branches connected in parallel and (n-1) negative coupling mutual inductors, and n is greater than or equal to 2; And the (n-1) negative coupling mutual inductors are connected to the n branches connected in parallel, one negative coupling mutual inductor is connected in series between every two adjacent branches, and one direct current switch is connected in series to each branch. According to the switch parallel dynamic current sharing circuit based on the negative coupling mutual inductors provided by the invention, the safety of the direct-current switch in parallel branches is improved.

The invention discloses an offshore wind power flexible direct current grid-connected system alternating current fault ride-through method based on energy regulation and control and belongs to the technical field of power transmission and distribution of power systems. According to the method, after an AC system at a receiving end fails, a DC voltage reference value is raised to a preset value of DC voltage, the capacitance energy reference value of a shore converter station is controlled to follow the actual value of the shore converter station; when the capacitance energy of the shore converter station reaches an early warning value, the capacitance energy reference value of an offshore converter station is raised to a preset maximum value, and then, the capacitance energy reference value of the offshore converter station is kept constant; and when the capacitance energy of the shore converter station reaches a preset maximum value, the AC power of the shore converter station is detected, calculation is performed to obtain the surplus power of a DC side, and the energy consumption power reference value of a DC energy consumption device is controlled to follow the surplus power. Therefore, waste caused by the surplus power and heat dissipation can be reduced, the operation economy is improved, and the operation characteristics of the energy consumption device are improved.

The present invention discloses a brushless DC motor method belonging to the electric power transmission technology field. According to the present invention, a preceding stage four-output level power converter and a next-stage two-level three-phase full bridge inverter are in cascade connection to be used as a power supply topology of the brushless DC motor, and an instantaneous current is used as a control variable. By switching the output levels of the preceding stage four-output level power converter continuously to control the instantaneous current to always track a reference value, and the commutation of the brushless DC motor is carried out by the on-off state of the next-stage two-level three-phase full bridge inverter. According to the method, a current harmonic wave generated by the PWM control can be reduced under a lower switching frequency, the dynamic response speed is improved, and the commutation torque ripple can be restrained effectively.

The invention discloses a charging and discharging MOS protection circuit. The charging and discharging MOS protection circuit comprises a battery and a protection circuit. The protection circuit comprises a current sampling resistor RS, a discharge control mosQD and a charge control mosQC. The protection circuit also comprises a discharge mos protection voltage-regulator tube ZD, a discharge mosprotection capacitor CD, a charge mos protection voltage-regulator tube ZC, and a charge mos protection capacitor CC, wherein the current sampling resistor RS is used for measuring current by a CPU; and the discharge mos protection voltage-regulator tube ZD and the charge mos protection voltage-regulator tube ZC provide voltage-limiting protection. According to the invention, the discharge mos protection capacitor CD and the charge mos protection capacitor CC have peak absorption capability; the capacitors are matched with the discharge mos protection voltage-regulator tube ZD and the charge mos protection voltage-regulator tube ZC to protect a mos, the faster the cut-off is, the higher the back voltage is, and after the mos is cut off, the change rate of the current is reduced by chargingand discharging the capacitors, so that the back voltage is reduced.

The invention discloses a power-on control circuit of an airborne laser photometer. The main technical content is that a first switch and a resistor are connected in series in the main power line of the laser photometer, and two circuits connected in series connect the two circuits. A second switch is connected in parallel to the end; a voltage monitoring circuit is connected in parallel to the energy storage capacitor of the laser photometer; the microprocessor controls the first and second switches to close and merge according to the power-on signal of the laser photometer and the effective signal of the voltage monitoring circuit. Send the charging completion information to the superior control system. The invention can connect the resistance into the main power line when the energy storage capacitor is charged, and separate the resistance from the main power line after the charging is completed, thus greatly reducing the current change rate of the laser photometer at the moment of power-on, effectively reducing the The external electromagnetic radiation of the main power line of the laser photometer improves the electromagnetic compatibility between the sensors of the airborne photoelectric stabilization platform.

The invention discloses a 24V diesel fuel delivery pump which comprises a brush direct current motor and a micro pump, the brush direct current motor comprises a stator assembly, a rotor, a carbon brush assembly and a carbon brush connector, the carbon brush assembly comprises an octagonal carbon brush, and one end of the rotor is provided with a ten-groove carbon commutator; one end face of the octagonal carbon brush is arranged opposite to one end face of the ten-groove carbon commutator, the other end of the rotor is connected with the micro pump, an advanced commutation area and a delayed commutation area are formed when the octagonal carbon brush makes contact with commutator segments of the ten-groove carbon commutator, the commutation period is prolonged on the premise that the rotating speed is not changed, and the current change rate is reduced. And the risk of electric sparks caused by contact between the carbon brush and the commutator is reduced. In addition, the ten-slot carbon commutator is adopted, so that the motor can adapt to severe environments, the problem of electrocorrosion generated when the copper commutator is in contact with the carbon brush is avoided, and the service life of the product is prolonged.

The invention relates to a switch-free switching auto-passing neutral section device for the electric railway, which is characterized in that high voltage large resistance electric resistance Rs are connected in series among a power supply arm U and a power supply arm D of any output phase alpha and beta of a three-phase-two-phase transformer T of a traction substation and a contact network neutral section M1 at the exit of the traction substation; the high voltage large resistance electric resistance Rs are also connected in series between ends of the power supply arm U and D of the traction substation and the contact network neutral section M2.The auto-passing neutral section device dispenses with a high voltage switch or a breaker, avoids transient overvoltage due to frequent switching, realizes safe and reliable auto-passing neutral section of an electric locomotive and saves operation costs and maintenance fees.

The invention provides an insulated gate bipolar transistor (IGBT) protection circuit and a motor control system, belonging to the filed of the motor control. The IGBT protection circuit comprises a sampling circuit, a feeding back circuit, a driving circuit and a slow turn-off circuit. The IGBT protection circuit adopts the slow turn-off circuit, thus the turn-off time of the IGBT is prolonged, the current change rate is reduced and the IGBT is protected against damage when the IGBT carries out the over-current protection.

The invention discloses a main circuit topology of an artificial zero-crossing technology, comprising a main current path and a current transfer circuit connected in parallel, wherein the main currentpath is formed by a mechanical switch S and a primary coil L1 of a saturation transformer T connected in series. The current transfer circuit consists of a pre-charging capacitor C, a control switchFV and a secondary winding L2 of the saturation transformer T which are connected in series. The connection terminal of the capacitor C with the mechanical switch S is a pre-charging negative electrode. The present invention also discloses a current transfer method thereof. The primary coil and the secondary coil of the saturation transformer T have opposite excitation magnetic potential directions during the current transfer process, and can quickly exit the saturation state before the current zero crossing of the mechanical switch S, so that the inductance of the transfer circuit is significantly increased. The current change rate near the current zero point of the mechanical switch S is reduced, and the high current breaking reliability of the mechanical switch S is improved.