178 results about "Active clamp" patented technology

The invention relates to the technical field of roller machining, in particular to a roller after-abrasion repairing device which comprises a machine tool, a rotating motor, a driving clamp and a driven clamp. A protective half cylinder; an upper protective cylinder and a lower protective cylinder; and the automatic switching and repairing device is arranged on the side, close to the protective half cylinder, of the machine tool. By means of the automatic switching repairing device, the multiple maintenance machine bases distributed in a circular array mode are arranged for automatic switching, so that the effect of conducting multiple maintenance on the roller is achieved, multiple maintenance work can be completed without carrying the roller through multiple machine tools, the working efficiency in the roller maintenance period is further improved, and the maintenance cost is reduced. The protective cylinder, the lower protective cylinder and the protective half cylinder are combined to form a complete cylinder shape, so that the effect of sealing and protecting a roller clamped between the driving clamp and the driven clamp is achieved, and the problem that chippings or water spots splash in the repairing work period such as polishing or cleaning of the roller is solved.

The active clamping circuit comprises a first energy storage element, a first branch circuit and a second branch circuit, the first branch and the second branch are connected in parallel and then connected in series with the first energy storage element; the first branch comprises a second energy storage element, and the second branch comprises an auxiliary switch tube; when the clamping circuit is in a forward charging state, the first energy storage element and the first branch are conducted to form a clamping loop; the first energy storage element and the second energy storage element absorb leakage inductance energy of the primary winding through the clamping loop; and when the clamping circuit is in a reverse excitation energy charging state for the transformer, the first energy storage element and the second branch are conducted to form a reverse excitation loop. As the voltage at the two ends is the sum of the voltage of the first energy storage element and the voltage of the second energy storage element during forward charging of the clamping circuit and is only the voltage of the first energy storage element during discharging, and the excitation voltage is smaller than the reflection voltage of the secondary winding during reverse excitation of the transformer, a secondary rectifier tube cannot be switched on, energy forward shock to the secondary side is eliminated, and the voltage of the secondary side is reduced. Therefore, the loss is reduced.

An insulated power supply apparatus includes, a transformer; a switching element connected in series with a primary side winding of the transformer; an active clamp circuit connected between terminals of the primary side winding of the transformer; and a power supply control semiconductor device. The switching element includes a field effect transistor and a current-voltage conversion element is connected between a source terminal of the switching element and a grounding point. The power supply control semiconductor device includes the following, a first external terminal in which voltage according to a drain side of the switching element is input, a second external terminal in which voltage converted by the current-voltage conversion element is input, an on / off control circuit that performs turn-on and turn-off of the switching element, and a ZVS determining circuit that determines whether zero voltage switching control is performed.

An active clamp flyback converter with safe operation is discussed. The active clamp flyback converter has a main power switch and an auxiliary switch integrated at a same IC chip. The active clamp flyback converter enables a first charge path from the power supply voltage to a floating capacitor when the main power switch is turned on. The first charge path is disabled and a second charge path from a second pin of the IC chip to the floating capacitor is enabled when a voltage at the second pin is higher than a reference voltage.

The invention discloses a multi-tube parallel power device phase shift type current sharing and crosstalk suppression drive circuit which is composed of a crosstalk suppression unit, a current balancing unit, a control response unit and a function switching unit. Wherein the crosstalk suppression unit generates a control signal for suppressing the crosstalk voltage of the parallel power device and shields the interference of the current balancing unit; the current balancing unit generates a control signal for balancing the dynamic current of the parallel power device and shields the interference of the crosstalk suppression unit; the control response unit is used for realizing crosstalk active clamping or current active equalization; and the mode switching unit realizes automatic switching of a crosstalk suppression function or a current equalization function according to configuration. Parallel device grid driving signal feedback is introduced, crosstalk voltage active clamping and dynamic current active balancing are achieved through a logic circuit, and the parallel expansibility is high; an exclusive-OR gate is adopted to accurately identify synchronous or asynchronous information of driving signals of the parallel devices, and various different gate sequential modes in parallel application of the hybrid devices can be compatible.

A power supply includes a noise suppression circuit, an active power factor correction circuit, an active clamp flyback conversion circuit, a voltage-stabilizing feedback compensation circuit, and a control circuit. The active power factor correction circuit and the active clamp flyback conversion circuit convert an AC voltage into an output voltage for driving a load. The voltage-stabilizing feedback compensation circuit performs voltage-stabilizing feedback compensation to the output voltage. The active clamp flyback conversion circuit switches its operational mode based on the instantaneous output loading of the power supply. The control circuit controls the operation of the voltage-stabilizing feedback compensation circuit based on the operational mode of the active clamp flyback conversion circuit, thereby adjusting the equivalent capacitance of the voltage-stabilizing feedback compensation circuit for providing a corresponding voltage-stabilizing feedback compensation range associated with the instantaneous output loading of the power supply.

The invention provides a zero-voltage starting control module, a driving circuit and an active clamping converter, and the module comprises a timing unit which carries out the timing of a first time length; the time length acquisition unit is used for acquiring the time length from the turn-off of the clamping tube to the complete release of the secondary inductive current of the transformer to obtain a second time length; the comparison unit is used for comparing the first duration with the second duration; and the dead time adjusting unit is used for adjusting the conduction time and the first duration of the clamping tube in the next period based on the comparison result of the current period so as to realize self-adaptive zero-voltage starting control. The circuit is realized by adopting a digital circuit, accurate control can be realized, the control range is relatively wide, zero-voltage conduction control is dynamically realized, the system efficiency is improved, the use of a capacitor in an analog circuit is reduced, and the area cost of a chip is reduced.

The present disclosure provides an active clamp flyback converter and a control method, and relates to the technical field of converter. The control method includes: in response to that an input voltage of the active clamp flyback converter is less than a preset voltage threshold, or the input voltage of the active clamp flyback converter is less than a product of an output voltage of the active clamp flyback converter and a turns ratio of the transformer, in a same switching cycle, controlling the clamp switch to turn on when the transformer is in a demagnetization stage; and controlling the clamp switch to turn off when a resonant current of the clamp capacitor and a leakage inductance of the transformer reaches a preset current threshold.

The invention discloses an active clamping control method and device and a switching power supply, and the method comprises the steps: determining whether a buck-boost cascade circuit is in a no-load state or a light-load state, and enabling the working mode of the buck-boost cascade circuit to be set as a discontinuous mode, the active clamping control mode of the buck-boost cascade circuit is set as a leading edge non-complementary mode; or, the working mode of the buck-boost cascade circuit is set to be a forced continuous mode, and the active clamping control mode of the buck-boost cascade circuit is set to be a trailing edge non-complementary mode; and determining that the buck-boost cascade circuit is in a heavy load state, setting the working mode of the buck-boost cascade circuit as a continuous mode, and setting the active clamping control mode as a trailing edge non-complementary mode. Corresponding sequential logic can be matched according to different working modes, the clamping effect of peak voltage at the two ends of a switching tube is optimized, ZVS can be achieved in a continuous mode, and the efficiency of the switching power supply is improved.

The invention relates to automatic reverse current regulation in an active clamped flyback converter. According to one embodiment, a method is presented that includes sensing a reverse current through a main switch of an active clamped flyback (ACF) converter. The ACF converter includes a flyback transformer and an auxiliary switch. The method further includes determining whether a sensed voltage corresponding to the reverse current exceeds a threshold; reducing a duration of the reverse current by an incremental time interval, the duration of the reverse current including a first incremental time interval, the duration of the reverse current corresponding to a duration in which the auxiliary switch is activated; increasing the duration by a second incremental time interval greater than the first incremental time interval, the increasing in response to the reverse current not exceeding the threshold; and activating the auxiliary switch for the duration to achieve zero voltage switching (ZVS).

A load driver includes an active clamping circuit coupled between gate and source terminals of a power stage. The active clamping circuit serves to either pass through a gate drive voltage (provided by a gate driver) to the power stage in a PWM mode or to actively clamp the voltage between gate and source terminals of the power stage to enable fast decay recirculation in fast decay mode (when the load driver is configured for active clamping). A semi-active recirculation driver is coupled between ground and the output of the power stage. The semi-active recirculation driver serves to either provide a low impedance recirculation path in the PWM mode or to passively clamp the output voltage to provide for a fast decay recirculation path in fast decay mode (when the load driver is configured for passive clamping).

The invention relates to the technical field of series voltage sharing of power electronic power devices, in particular to a dynamic voltage sharing circuit of a high-voltage integrated gate commutated thyristor (IGCT) series valve group and a control method of the dynamic voltage sharing circuit of the high-voltage IGCT series valve group. The voltage is monitored in real time; the overvoltage energy release unit is used for releasing transient overvoltage energy; all the active clamping circuits are connected in series to form a clamping matrix, corresponding overvoltage energy discharge units are triggered when overvoltage is detected, and transient voltage sharing is optimized by the central controller in combination with an arbitration strategy. By improving the voltage balancing capability between the IGCT device valve group modules, transient overvoltage energy can be quickly sensed and released, the dynamic voltage balancing problem is effectively solved, the system operation stability is improved, meanwhile, the power consumption in the online operation process is remarkably reduced, the size of a heat dissipation system is reduced, and the power density of the converter valve is greatly improved.

The invention relates to the technical field of power electronics, and discloses a dynamic regulation and control method and system for an active clamping three-level converter adapting to working condition changes, and the method comprises the steps: calculating the loss sample data of each power device in different modulation modes through obtaining the historical data of characteristic parameters under different working conditions; calculating the junction temperature of the power device based on the loss in the hybrid modulation mode; with the minimum junction temperature distribution imbalance degree as a target, calculating a hybrid modulation coefficient, and constructing a neural network model; after operation parameters of a power device are collected in real time, the optimal modulation coefficient is obtained based on the model, the modulation mode of the converter is dynamically adjusted, and loss distribution is optimized. According to the method, the loss distribution characteristic and efficiency of the converter under all working conditions can be improved, and the loss balance performance is optimized.

An isolated switching power supply circuit is compact, high-efficiency, and low noise. It includes a transformer T1 which has a primary winding wound with NP turns and a secondary winding wound with NS turns, a drive switch Q1 and an active clamp switch Q2 configuring a primary side half-bridge, a boost capacitor CBULK1 that charges a discharge energy of the transformer, rectifier diodes D1 and D2 connected in series, a tank capacitor CT1, and an output capacitor COUT1. A secondary side winding voltage, when the drive switch Q1 or the active clamp switch Q2 is on, is held in the tank capacitor CT1, and by superimposing the secondary winding voltage, when the drive switch Q1 or the active clamp switch Q2 is off, on the voltage held in the tank capacitor CT1, the configuration is such that output voltage VOUT equals boosted voltage VBULK times (NS divided by NP).

The utility model discloses an active clamping forward switching power supply with dead zone control. The active clamping forward switching power supply comprises a minimum pulse circuit, a dead zone setting circuit, a signal interlocking circuit and an active clamping forward switching circuit, the minimum pulse circuit, the dead zone setting circuit and the signal interlocking circuit are connected in sequence; the active clamping forward switching circuit comprises a transformer T1, the two ends of a primary side winding of the transformer T1 are connected with a clamping absorption circuit in parallel, a primary side negative electrode of the transformer is connected with a main power circuit, and the clamping absorption circuit and the main power circuit are connected with a signal interlocking circuit. The circuit can flexibly set dead time to avoid circuit failure caused by direct connection of a clamping tube and a main power switch tube, input signal burrs can be eliminated, mistaken switching-on caused by the signal burrs can be avoided, one path of PWM can be converted into two paths of PWM output, and the number of external equipment is reduced.

The invention discloses a three-level current type push-pull bidirectional DC-DC converter, relates to the technical field of power electronics, and is used for realizing bidirectional energy conversion between low voltage and high voltage. The converter comprises a low-voltage side circuit, a high-voltage side circuit, a transmission inductor and a control unit. The low-voltage side circuit is composed of a boost inductor, an active clamping circuit and a push-pull transformer. The high-voltage side circuit adopts a three-level half-bridge structure, and voltage boosting is realized through a voltage-multiplying capacitor; the transmission inductor is used for efficient bidirectional power transmission. And the control unit adopts a PWM + phase shift composite control strategy to accurately adjust the duty ratio, the inter-bridge shift phase ratio and the intra-bridge shift phase ratio, so that the accurate control of the power transmission direction and size is realized. According to the converter, the switching loss is reduced while the conversion efficiency is improved, the system stability is improved, and the converter is suitable for high-efficiency energy transmission application of electric vehicle charging, an energy storage system, a renewable energy source power grid and the like. Through optimization design, the reliability and adaptability of the system can be greatly improved.

An active clamp photoelectric sensing device includes an input terminal, a first output terminal, a current-to-voltage conversion circuit, and an active clamp circuit. The input terminal receives an input current. The first output terminal outputs a first output voltage. The current-to-voltage conversion circuit is coupled between the input terminal and the first output terminal, and is used to discharge and lower potentials of the input terminal and the first output terminal to a first set voltage according to the state of a reset signal, or is used to gradually increase the first output voltage to a second set voltage. The active clamping circuit is coupled to the current-to-voltage conversion circuit, and is used to clamp the upper limit of the first output voltage to the second set voltage.

In a switch system, a voltage clamping element is connected to a semiconductor switch in parallel. An active clamping circuit is connected between a control terminal and a first main terminal of the semiconductor switch. The active clamping circuit includes a first diode, a second diode, and a control switch. A second anode of the second diode is connected to a first anode of the first diode. The control switch is connected between the first anode of the first diode and the control terminal of the semiconductor switch. A second control unit controls the control switch. A breakdown voltage of the first diode is smaller than a clamp voltage of the voltage clamping element.

The present invention relates to the technical field of roller processing, and specifically to a device for repairing worn rollers, comprising a machine tool, a rotating motor, an active clamp, a passive clamp, a protective half-cylinder, an upper protective cylinder, and a lower protective cylinder; and an automatic switching repair device, wherein the automatic switching repair device is disposed on a side of the machine tool near the protective half-cylinder. The present invention utilizes the automatic switching repair device to provide a plurality of repair stands distributed in a circular array for automatic switching, thereby achieving the effect of performing multiple repairs on the rollers. Multiple repair tasks can be completed without the rollers having to be transported across multiple machine tools, further improving work efficiency during roller maintenance. The protective cylinder, the lower protective cylinder, and the protective half-cylinder are combined to form a complete cylindrical shape, thereby achieving the effect of providing a closed protection for the roller clamped between the active clamp and the passive clamp, thereby preventing problems such as debris or water splashing during roller repair work such as grinding or cleaning.

The utility model relates to a switching power supply circuit and electronic equipment. The circuit comprises a power supply input end, a power supply output end, a transformer comprising a primary winding and a secondary winding, a main power switch unit, an active clamping unit, a clamping driving unit, a voltage dividing unit and a built-in MOS control chip. The main power switch unit is connected with the power supply input end, the primary winding and the voltage division unit, and is switched on when receiving voltage division output of the voltage division unit; the voltage dividing unit is connected with the power supply input end and the built-in MOS control chip, and generates divided voltage output when the built-in MOS control chip is switched on; the clamping driving unit is connected with the built-in MOS control chip and generates a first driving level when the clamping driving unit is switched on and generates a second driving level when the clamping driving unit is switched off, and the active clamping unit is connected with the primary winding and the clamping driving unit, is switched off when receiving the first driving level and is switched on when receiving the second driving level. According to the utility model, the loop loading capability and the voltage stress bearing capability can be improved through a simple circuit design.

A power converter includes a transformer, a main switch, an active clamp switch, and a primary side controller circuit. The primary side controller circuit is configured to indirectly measure a magnetizing current through the transformer during a first switching cycle of the power converter and estimate a zero-crossing point of the magnetizing current for a second switching cycle based on the indirect primary side measurement of the magnetizing current. Based on the estimated zero-crossing point, the primary side controller circuit generates an auto-tuned delay, for the second switching cycle, between disabling the main switch and enabling the active clamp switch before the zero-crossing of the magnetizing current occurs. The active clamp switch is enabled during the second switching cycle in accordance with the auto-tuned delay.

The present invention is applicable to the technical field of inverters, and provides a midpoint active clamped three-level inverter, a control method and a control device. The midpoint active clamped three-level inverter includes: a bridge arm unit, a clamping unit connected to the bridge arm unit, and a bridge arm output end connected to the bridge arm unit; the bridge arm unit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a first diode, a second diode, a third diode and a fourth diode connected in anti-parallel to the first switch tube, the second switch tube, the third switch tube and the fourth switch tube; the clamping unit includes a fifth switch tube, a sixth switch tube, a fifth switch tube and a sixth diode connected in anti-parallel to the sixth switch tube; the fifth diode and the sixth diode are silicon carbide diodes. The present invention can reduce uneven heating of each switch tube and improve the efficiency and stability of electric energy conversion.

The invention relates to a converter circuit and electronic equipment. The converter circuit comprises an active clamping circuit, a control circuit and a voltage stabilizing circuit, active devices in the active clamping circuit are controlled through the active clamping circuit to realize soft switching, that is, a first switching tube and a second switching tube are controlled to realize soft switching, so that the conduction loss of the first switching tube and the second switching tube is reduced, and the switching efficiency is improved. The problem that large loss is caused when the PFC converter works at high frequency due to the fact that an existing passive clamping circuit cannot achieve soft switching is solved.

A controlling method of a power converter includes performing a first switch controlling step and a second switch controlling step. The first switch controlling step is performed to control a primary switch of the power converter by a first controlling signal. The second switch controlling step is performed to control an active clamp switch of the power converter by a second controlling signal. The primary switch is turned on by the first controlling signal at each of a plurality of power converter switching cycles. The active clamp switch is not turned on by the second controlling signal at a part of the power converter switching cycles, and the active clamp switch is turned on by the second controlling signal at another part of the power converter switching cycles.

The present invention discloses a constant voltage control system for a primary side feedback active clamp flyback converter, which includes a sampling module, an auxiliary switch tube conduction time calculation module, a PID control module, and a switch tube control module; the sampling module samples the auxiliary winding feedback voltage at the moment when both the output diode and the auxiliary switch tube are conducting, and outputs the feedback voltage to the PID control module; the PID control module outputs a peak current target value to the auxiliary switch tube conduction time calculation module and the switch tube control module; the auxiliary switch tube conduction time calculation module designs and outputs the conduction time control parameter of the auxiliary switch tube to the switch tube control module through the slopes of different charging stages after the main switch tube is turned off; the input of the switch tube control module is the conduction time control parameter of the auxiliary switch tube and the peak current target value, and it outputs the duty cycle control signals for the main switch tube and the auxiliary switch tube to switch. The present invention solves the sampling problem of constant voltage control in the CCM mode of the active clamp flyback converter.

A power supply comprises a transformer having a primary winding, a first switch coupled to the primary winding and to a voltage input, an active clamp circuit coupled in parallel with the primary winding, and a clamp switch control coupled to the active clamp circuit. The power supply further comprises a bootstrap circuit coupled to the clamp switch control and having a bootstrap voltage storage device coupled to the clamp switch control. A charging circuit has a resistor network configured to generate a charge voltage in response to an input voltage supplied by the primary winding. A charge voltage storage device is configured to store at least a portion of the charge voltage during the first portion of the switching cycle and to supply the at least a portion of the charge voltage to the bootstrap voltage storage device during a second portion of the switching cycle.

A controlling method of a power converter includes performing a first switch controlling step and a second switch controlling step. The first switch controlling step is performed to control a primary switch of the power converter by a first controlling signal. The second switch controlling step is performed to control an active clamp switch of the power converter by a second controlling signal. The primary switch is turned on by the first controlling signal at each of a plurality of power converter switching cycles. The active clamp switch is not turned on by the second controlling signal at a part of the power converter switching cycles, and the active clamp switch is turned on by the second controlling signal at another part of the power converter switching cycles.

The invention belongs to the field of power electronics, and discloses an active clamping circuit and method for inhibiting crosstalk of a silicon carbide MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), symmetrical dual active clamping driving sub-circuits are adopted, and each sub-circuit responds to a driving signal through a control tube and dynamically manages the on-off state of a clamping tube. When the first silicon carbide MOSFET is conducted to cause crosstalk, the control tube on the turn-off side is cut off to enable the clamping tube to be conducted, the gate-source voltage of the second silicon carbide MOSFET is clamped to negative voltage, and forward misconduction and negative breakdown are avoided; during the turn-off period of the double tubes, displacement current is discharged by a low-impedance path of the clamping tube; when the second silicon carbide MOSFET is conducted, the control tube is turned on to turn off the clamping tube, and the voltage clamping is relieved. The circuit overcomes the defects that gate pole resistance affects the switching speed, passive clamping lacks dynamic response and external signal delay exists, and the switching speed, the system reliability and the control cost are considered while crosstalk peaks are restrained; not only is the high-frequency switching advantage of the silicon carbide MOSFET maintained, but also the safety of the grid electrode is protected through accurate voltage clamping.

The present invention discloses a circuit and a control method for preventing a semiconductor switch device from being turned on by mistake. The circuit includes: an active clamping circuit, a control circuit, a power amplifier circuit and an interference suppression circuit; the control circuit is coupled to the input end of the power amplifier circuit; the output end of the power amplifier circuit is coupled to the gate of the semiconductor switch device; the first end of the active clamping circuit is connected to the first end of the semiconductor switch device, and the second end is connected to the input end of the power amplifier circuit. The active clamping circuit is configured to act within a preset time period from the moment when the voltage between the first end and the second end of the semiconductor switch device is greater than the preset voltage; the interference suppression circuit includes a controllable switch; the controllable switch is configured to be turned on after the action of the active clamping circuit is completed, so that the potential of the input end of the power amplifier circuit is clamped to a fixed potential. The present invention can effectively prevent the active clamping circuit from causing the switch device to be turned on by mistake due to the increase of the energy injected into the gate of the switch device.

Solid-state circuit breakers (SSCBs) have been witnessing an impressive progress with the aid of wide bandgap (WBG) devices such as silicon carbide (SiC) MOSFETs. Along with obtaining high efficiency as the result of low on-state resistance, response times have been gaining remarkable achievements in microseconds range. Not only that, the reported successes in control and gate drivers design and incorporating fault detection / location techniques in SSCBs are promising. A MOV-resistive capacitive switch (MOV-RCS) snubber for solid state circuit breakers addresses the following: 1) the MOV degradation issue in DCCBs is solved, 2) the maximum allowable DC bus voltage on DCCBs is extended. The solid state circuit breaker and an active clamping snubber includes a first circuit including a fault current bypass based solid state breaker for low voltage direct current systems.