218 results about "Turn off time" patented technology

The present invention provides a DCDC converter using a dual-mode adaptive off-time timer, comprising: a PWM comparator, an on-time timer, a current detection module, an off-time timer logic control circuit, a drive control circuit, a dual-mode adaptive off-time timer, an inductor LOUT, an NMOS transistor MH, an NMOS transistor ML, a resistor RFB2, a resistor RFB1, and a capacitor COUT. The present invention is implemented by means of the PWM comparator, the on-time timer, the current detection module, the off-time timer logic control circuit, the drive control circuit, and the dual-mode adaptive off-time timer. The off-time of the internal dual-mode adaptive off-time timer has the function of adaptively adjusting an input signal and an output feedback signal, and a minimum off-time timer and an overcurrent off-time timer are simultaneously implemented by using one off-time timer.

The present invention provides a control circuit of an isolated power supply and an isolated power supply. A secondary side controller in the control circuit can turn on and off a synchronous rectifier based on a voltage from a secondary side winding, enabling adaptive turn-on and turn-off control of the synchronous rectifier. Specifically, when the voltage from the secondary side winding reaches a second predetermined voltage, an instruction for turning off the synchronous rectifier is provided. The second predetermined voltage is adjusted based on a comparison between a time interval for the previous switching period and a predetermined reference interval. In this way, a delay from a turn-off time of the synchronous rectifier to a turn-on time of a primary transistor switch is substantially maintained at the predetermined reference interval. This prevents cross-conduction of the primary and secondary side circuits, ensuring safe operation of the isolated power supply.

The invention provides an IGBT (Insulated Gate Bipolar Translator) turn-off time measuring method, system, equipment and medium, and belongs to the field of power semiconductor device testing technology and state monitoring, and the method comprises the following steps: firstly, selecting 20% Vdc and 80% Vdc as turn-off initial measuring points, secondly, carrying out first error correction by adopting a linear estimation method, and finally, carrying out second error correction by adopting a linear estimation method; performing linear fitting on the voltage difference Vce data through a least square method to obtain initial turn-off time; and finally, aiming at systematic deviation caused by inherent concavity and convexity characteristics of the voltage curve, performing secondary error correction by adopting a convex hull algorithm, acquiring a lower envelope line of the ic-tOFF relation curve through an Andriw algorithm, and identifying and eliminating the problem of Overestimation of the turn-off time based on a convex hull accurate point set. According to the invention, accurate measurement of the turn-off time of the IGBT under the condition of low sampling rate is realized, the hardware cost is significantly reduced, and a reliable technical basis is provided for IGBT state monitoring and life prediction.

The invention discloses a power modulation method and system for an all-solid-state power supply, and belongs to the technical field of pulse power. The method comprises the following steps: converting a target waveform into a multi-level discrete waveform, and segmenting the multi-level discrete waveform into a plurality of continuous sub-waveforms according to polarity; for each sub-waveform, identifying all level switching moments, obtaining a time-level number corresponding relation, and generating a corresponding switching action time sequence matrix; the row index of the switching action time sequence matrix corresponds to the level number, the odd-numbered columns store the turn-on time parameters of the switching devices under the corresponding level number, and the even-numbered columns store the turn-off time parameters of the corresponding switching devices; and converting the switching action time sequence matrix into period counting based on an FPGA main clock, and generating a corresponding driving pulse signal by the FPGA according to time sequence data so as to control a switching device in the all-solid-state power supply and carry out power modulation. High-real-time and high-precision control on the switch of the solid-state power supply is realized, and the effect of arbitrary waveform power modulation is realized.

A rectifier includes digital timers to control FET switching rather than direct measurement of current and / or voltage. The digital timers control turn-off time to compensate for a delay produced by comparators in the rectifier. The digital timers are adjusted over multiple cycles to arrive at a turn-off time that produces zero current turn-off. The digital timers may be periodically or continuously readjusted based on a preceding set of cycles. Adaptive turn-off via digital timers is useful for discontinuous conduction mode suppression.

The invention discloses an anti-saturation equivalent virtual impedance grid-forming type SVG fault current-limiting control method, which comprises the following steps of: inverting a direct current into an alternating current through an inverter, and filtering high-frequency harmonics through a filter to obtain a sine wave alternating current meeting a grid-connected requirement. A three-phase alternating current signal is collected in real time, coordinate transformation is carried out through a Park transformation module, and a modulation signal is obtained. The modulation signal is compared with a triangular carrier signal, a driving signal is generated, the on-off time of a power switching device of the inverter is controlled, the amplitude and phase of output voltage and current are adjusted, accurate control over the output power of the grid-connected inverter is achieved, and the power grid access requirement is met. According to the method, the limitation of traditional fixed parameters is broken through, and the robustness of the system to a complex fault scene is improved. In addition, manual intervention or a complex mode switching program is not needed, automatic smooth transition between different working conditions can be achieved, and powerful technical guarantee is provided for stable operation of a power grid.

The invention provides a control method for dead time of a power unit. The power unit comprises a power semiconductor device module and a driving module. The control method comprises the steps of obtaining a current value of the power unit; determining the turn-off time of the power semiconductor device module according to the current value and a preset relation table, wherein the preset relation table comprises a corresponding relation between the determined current value and the turn-off time based on the type of the power semiconductor device module; determining the dead time of the power semiconductor device module according to the turn-off time; and determining a driving pulse of the driving module according to the dead time, so that the driving pulse controls the power semiconductor device module to realize the dead time. According to the technical scheme of the invention, the dead time of the power semiconductor device module is automatically updated according to the current value of the power unit, and the probability of current short circuit caused by simultaneous conduction of two power switches in a bridge arm in the power semiconductor device module is reduced. And thus, the stability of equipment or a system comprising the power unit is improved.

The invention discloses a load transient detection circuit of a COT Buck, a corresponding COT Buck and a switching power supply. The load transient detection circuit comprises an input end, three resistors connected in series, two comparators and a switched capacitor sampling hold circuit, wherein the input end is grounded after passing through the three resistors in sequence. A node between the input end and the first resistor and a node between the second resistor and the third resistor are connected to the input ends of the first comparator and the second comparator through a switched capacitor sampling hold circuit structure. Valley voltage information and peak voltage information of inductive current are obtained through the switched capacitor sampling hold circuit, whether a load is transiently changed or not is judged by comparing inductive current ripples with a valley value and a peak value, and it is guaranteed that the switching power supply has appropriate transient detection trigger threshold voltage under any load. According to an output signal of the load transient detection circuit, the COT Buck can increase the turn-on or turn-off time so as to enhance the transient response speed.

The invention relates to the technical field of output control, in particular to a COT-based constant voltage control method, device and equipment and a storage medium, and the method achieves the precise control of the total duration of a target period through the dynamic adjustment of the turn-off time on the basis of the fixed turn-on time, can quickly respond to the sudden change of a load, and improves the stability of the load. The overshoot or undershoot phenomenon of the output voltage is reduced; specifically, voltage information is sampled in real time within the period conduction time, and the turn-off time of the next period is immediately adjusted after the period is ended, so that error accumulation caused by delayed adjustment in a traditional control mode is avoided, the dynamic response capability to battery voltage fluctuation is enhanced, and the output precision is improved; besides, a strategy of synchronous opening and unified adjustment of turn-off time is adopted, so that the consistency of the turn-off time of multi-path output in a starting stage and a subsequent period is ensured, load change disturbance caused by asynchronous turn-off is avoided, and voltage rise deviation of a later turn-off channel is reduced.

The application discloses an energy-saving control method of a CSR high-frequency PWM rectifier circuit. According to the value change of each line voltage of three-phase alternating current in a rectifier circuit and the characteristic that the rectifier circuit works at a high frequency, the two pulse wave edges of two phases of the three-phase alternating current are overlapped. The overlapping time of the overlapping of the two pulse wave edges is equal to the sum of the turn-on time and the turn-off time of a switching tube, so that the front edge or the rear edge of a pulse of a switching signal is in a soft switching state or in a cut-off low voltage state, thereby reducing the switching process loss of the switching tube. The application provides the energy-saving control method of the CSR high-frequency PWM rectifier circuit, which can reduce switching loss, reduce cost, save energy, prolong service life and is safe and reliable.

A voice coil motor (VCM) in a hard disk drive is operated in a discontinuous mode with an alternation of on and off times. A drive current to the VCM is facilitated and countered with a variable voltage across the during the on-times and off-times. The intensity of the drive current is controlled as a function of a Back ElectroMotive Force (BEMF) of the VCM. A method includes sampling during the alternation of on-times and off-times first and second values of the voltage across the VCM. The first value is sampled at a first time in response to the end of the off-time. The second value is sampled at a second time in response to the drive current of the VCM zeroing following the supply of drive current to the VCM being countered during the off-time. The BEMF is calculated as a function of first and second values.

An apparatus includes a buck converter portion of a buck-boost converter configured to operate under a constant on-time control scheme, wherein an on-time of a high-side switch of the buck converter portion is determined by a buck on-time timer, and a boost converter portion of the buck-boost converter configured to operate under a constant off-time control scheme, wherein an off-time of a low-side switch of the boost converter portion is determined by a boost off-time timer.

The invention relates to the technical field of output control, in particular to a constant power control method, device and equipment based on COT and a storage medium, according to the method, fixed turn-on time is combined with dynamic turn-off time adjustment, the conciseness of COT control is reserved, accurate control over output power is achieved, and the control efficiency is improved. The influence of interference factors such as battery voltage drop and load abrupt change on constant power output can be effectively counteracted; specifically, a multi-path output synchronous opening design is adopted, and unified turn-off time adjustment logic is combined, namely, the turn-off time of a (k + 1) th period is calculated according to the total duration of a target period, so that an asynchronous turn-off condition caused by parameter differences of all channels is avoided, and the voltage rise deviation generated by load changes of a later turn-off channel is reduced; real-time output voltage and load resistance are respectively sampled in one period, battery voltage fluctuation and load change are monitored in real time, and error accumulation caused by the fact that a measured value in the current period is extended to the next period to be adjusted is avoided.

Controller and method for a constant-current switch-mode power converter. For example, a controller for a constant-current switch-mode power converter includes: a constant-current controller configured to receive an input voltage and generate a modulation signal based at least in part on the input voltage; and a driver configured to receive the modulation signal, generate a drive signal based at least in part on the modulation signal, and output the drive signal to a transistor coupled to an inductive coil and a resistor; wherein: the drive signal corresponds to at least one switching cycle; the switching cycle includes an on-time during which the drive signal is at a first logic level and an off-time during which the drive signal is at a second logic level; and the off-time includes a demagnetization period during which the inductive coil undergoes a demagnetization process.

The present invention relates to the technical field of SiC power devices, and more specifically, to a multi-layer circuit protection structure for SiC power devices. The structure comprises at least two SiC power devices, each of which is connected in parallel; and a drive circuit, wherein each gate of each SiC power device is connected to a turn-on path and a turn-off path. By improving the drive circuit, the present invention achieves a structure in which the drive circuit differentially adjusts the gate resistance of each device to offset the switching time difference caused by Vgs-th differences, thereby reducing or compensating for the turn-on and turn-off time differences caused by Vgs-th differences, and solving the problem of thermal runaway caused by large Vgs-th differences.

The application relates to a critical conduction mode control method of a totem-pole PFC converter, which utilizes energy equivalence to determine the resonance process of inductor current at switching commutation, carries out totem-pole Boost inductor current value estimation, and on this basis, utilizes a current zero-crossing point prediction algorithm to calculate the turn-on and turn-off time to generate corresponding active tube-synchronous rectifier tube commutation dead time T d,f , synchronous rectification conduction time T SR , rectifier tube-active tube commutation dead time T d,r ; the PWM drive signals of high-speed switching tubes Q1 and Q2 are generated by T on , T d,f , T SR , T d,r ; the power frequency drive signals of low-speed switching tubes Q3 and Q4 are generated by comparing the input alternating voltage v ac with a hysteresis comparison loop and 0. The method can effectively get rid of the dependence on a current zero-crossing detection circuit and a current sensor, reduces the cost and improves the system stability.

The present invention relates to direct current transmission technology, and specifically to a method for determining the voltage and current during the turn-off process of a thyristor converter valve of an anode saturated reactor. The method comprises: simplifying the external circuit of the thyristor converter valve during the turn-off transient process; establishing a thyristor equivalent circuit during the turn-off transient process; establishing an equivalent model of the stored charge inside the thyristor during the turn-off process, taking into account the tolerance of the thyristor and setting different stored charges to obtain a thyristor equivalent model during the turn-off transient process; establishing an SR nonlinear model of the anode saturated reactor; obtaining the voltage and current magnitude of the thyristor converter valve at any moment during the turn-off process, as well as the voltage and current waveforms of the thyristor converter valve during the entire turn-off process. This method accurately analyzes the impact of the anode saturated reactor on the turn-off process; takes into account the different turn-off times caused by different stored charges due to the tolerance of the thyristor and the resulting impact, and can obtain the voltage across the thyristor and the current flowing through the thyristor at any point in the entire turn-off process.

This invention discloses a load transient detection circuit for a COT Buck converter, along with a corresponding COT Buck and a switching power supply. The load transient detection circuit includes an input terminal, three resistors connected in series, two comparators, and a switched-capacitor sample-and-hold circuit. The input terminal is grounded after passing through the three resistors. The nodes between the input terminal and the first resistor, and between the second and third resistors, are connected to the input terminals of the first and second comparators via the switched-capacitor sample-and-hold circuit. The valley and peak voltage information of the inductor current is obtained through the switched-capacitor sample-and-hold circuit. By comparing the inductor current ripple with the valley and peak values, a transient change in the load is determined, ensuring that the switching power supply has a suitable transient detection trigger threshold voltage under any load. The COT Buck of this invention increases the on or off time based on the output signal of the load transient detection circuit to enhance the transient response speed.

The utility model belongs to the field of static change-over switches, and provides a static change-over switch, which comprises a machine body provided with an external power supply connecting end, a load connecting end and a standby power supply connecting end, and the standby power supply connecting end is electrically connected with the load connecting end; and the mainboard and relay integration is arranged in the machine body and is electrically connected with the mainboard, the external power supply connecting end, the load connecting end and the standby power supply connecting end. Compared with the prior art, the static change-over switch has the advantages that the relay is integrally arranged in the machine body and matched with the main board, the relay is adopted as a turn-off element of the static change-over switch, the turn-off time can be shortened to about 10ms, the defect that a thyristor does not conform to safety regulations is overcome, and the defects that a contactor is low in turn-off speed and high in cost are overcome. According to the technical scheme, the static change-over switch is economical and low in manufacturing cost, the stability and reliability of the whole system are guaranteed, and rapid switching of the static change-over switch between the grid-connected mode and the off-grid mode can be achieved.

The application discloses a power modulation method and system of a full solid-state power supply, and belongs to the technical field of pulse power. The method comprises the following steps: converting a target waveform into a multi-level discrete waveform, and dividing the multi-level discrete waveform into a plurality of continuous sub-waveforms according to polarity; for each sub-waveform, identifying all level switching moments to obtain a time-level number corresponding relationship, and generating a corresponding switch action time sequence matrix; the row index of the switch action time sequence matrix corresponds to the level number, and the odd columns store the turn-on time parameters of the corresponding switch devices under the corresponding level number, and the even columns store the turn-off time parameters of the corresponding switch devices; the switch action time sequence matrix is converted into period counting based on the main clock of the FPGA, and the FPGA generates corresponding driving pulse signals according to the time sequence data, so as to control the switch devices in the full solid-state power supply and perform power modulation. The switch of the solid-state power supply is controlled with high real-time performance and high precision, and the effect of arbitrary waveform power modulation is realized.

The invention discloses a synchronous motor excitation system electronic field suppression switch and a control method thereof, the synchronous motor excitation system electronic field suppression switch comprises an excitation transformer, the excitation transformer is electrically connected with a rectifier bridge, one end of the rectifier bridge is electrically connected with an electronic field suppression switch, and the electronic field suppression switch is electrically connected with a motor excitation winding. The synchronous motor is arranged at one end of the motor excitation winding, the silicon controlled rectifier bridge and the electronic field suppression switch are both controlled by the control device, an electronic circuit is adopted for control, the on-off time is controlled to be millisecond level, the control precision is high, the reliability is high, a tedious relay control loop and a mechanical operation loop of the field suppression switch are omitted, and the cost is reduced. Due to the fact that the electronic field suppression switch directly achieves work and disconnection of the excitation loop through the electronic circuit, when the excitation loop is disconnected, no contact of a traditional field suppression switch exists, high-voltage direct-current arcs are generated when the loop is disconnected, and accidents that the field suppression switch is damaged due to improper treatment of the high-voltage direct-current arcs are avoided.

The application discloses a dead time control circuit and electronic equipment, and belongs to the technical field of electronics. The dead time control circuit comprises an inductive element, a first field effect tube connected with the inductive element, a second field effect tube connected with the inductive element and the first field effect tube, a detection circuit for detecting a first switching state of the first field effect tube, a second switching state of the second field effect tube and a current flow direction of the inductive element, a logic judgment circuit for outputting an adjustment mode signal of a dead time, a first off time and a second off time according to the first switching state, the second switching state and the current flow direction, an operation circuit for outputting a dead time control signal according to the first off time and the second off time in an adjustment direction indicated by the adjustment mode signal, and a time delay circuit, wherein the dead time control signal is used for adjusting a time delay value of the time delay circuit to adjust the dead time of the first field effect tube and the second field effect tube.

The invention discloses a self-adaptive direct connection prevention double-N-type output driving circuit which comprises a first control circuit, a second control circuit, an output driving stage upper tube, an output driving stage lower tube, a diode D1, a resistor R1 and a resistor R2. The output driving stage upper tube MN1 and the output driving stage lower tube MN2 are NMOS (N-channel metal oxide semiconductor) tubes; the first control circuit is used for controlling the output driving stage upper tube to be conducted when a first time sequence signal CLK is valid; and the second control circuit is used for controlling the output driving stage lower tube to be switched on in a time delay manner when the first time sequence signal CLK is invalid. In the invention, the switch-on time and the switch-off time of the two channels can be respectively controlled by adjusting the resistor R1 and the resistor R2, and an NMOS tube with higher carrier mobility is used as a pull-up tube, so that the current pull-up capability is stronger; and self-adaptive conduction of the output driving stage upper tube and the output driving stage lower tube is formed, so that the high-speed GaN power tube driver can be suitable for a high-speed GaN power tube driver.

The present invention relates to a DC-DC circuit and a control method thereof, which are used in the field of electronics. The circuit includes an oscillator that provides a clock signal CLK to a system, a PWM comparator that compares an output voltage feedback signal VFB with a reference voltage VREF and outputs a level signal Y1, a PFM controller that generates a duty cycle control signal PWM based on the CLK signal and the Y1 signal, a power tube driving circuit that generates a DRV1 signal and a DRV2 signal based on the PWM signal, a power tube that is turned on and off by the DRV1 signal, and a synchronous tube that is turned on and off by the DRV2 signal, and a zero-crossing comparator that generates a level signal Y2 by comparing voltage drops across the synchronous tube to control the turn-off time of the synchronous tube in a discontinuous mode. The circuit is characterized in that the circuit also includes a dynamic bias circuit that controls the bias current output to the PWM comparator and the zero-crossing comparator based on the length of the power tube turn-off time.

The circuits and methods of the present disclosure control the active off-time (high side switch on-time) to ensure the magnetization energy release and resonant capacitor energy release in an asymmetrical half-bridge (AHB) converter finish at the same time and all the stored energy is delivered to the output in each switching cycle. Multiple, parallel, techniques to control the high side switch on-time are illustrated. One is to track the volt-seconds applied during the storage cycle and allow the active release off-time to be limited to the same volt-seconds. A second option is to provide a high side switch on-time that is proportional to the on-time of the low side switch in that switching cycle. A third option is to provide a maximum high side switch on-time that can be programmed to ensure the high side on-time is equal to or smaller than half of the resonant period.

The invention discloses an IGBT module bonding wire aging state evaluation device and method and a medium, and relates to the field of IGBT module aging state evaluation, and the device comprises a device turn-off condition detection module which is used for detecting the turn-off voltage and turn-off current of an IGBT module to determine the current turn-off condition of the IGBT module; the turn-off time detection module and the current drop time detection module are respectively used for detecting the turn-off time and the current drop time of the IGBT module under the current turn-off condition; and the bonding wire aging state evaluation module is used for evaluating the aging state of the bonding wire of the IGBT module according to the turn-off time and the current falling time of the IGBT module under the current turn-off condition. According to the invention, the aging state of the bonding wire of the IGBT module is evaluated based on the turn-off time and the current drop time, and the evaluation accuracy is improved.

Embodiments of the present disclosure provide a turn-off time control circuit for a DC-DC converter, which includes: an error voltage scaling circuit, a selection circuit, an output voltage simulation circuit, a reference voltage generation circuit, and a clock signal generation circuit. The error voltage scaling circuit scales the error voltage to generate a scaled signal. The selection circuit generates first and second selection signals according to the feedback voltage and the second reference voltage and provides the scaled signal to the first node when the first selection signal is at an effective level. The output voltage simulation circuit generates and provides an analog output voltage to the first node when the second selection signal is at an effective level. The reference voltage generation circuit generates a third reference voltage according to the voltage of the first node and the input voltage. The clock signal generation circuit generates a clock signal according to the third reference voltage, the input voltage, and the voltage of the second pole of the power transistor. The clock signal is used to control the turn-off time of the power transistor. The on-time of the power transistor is controlled by the error voltage.

The objective is to provide a control device for a rotating electric machine that can prevent the generation of gate command signals that attempt to perform synchronous rectification during an abnormal period, even when the diode on-timing or diode off-timing cannot be correctly detected. [Solution] The control device 100 includes a synchronous rectification permission signal generation unit that generates synchronous rectification permission signals Swp and Swn based on the conduction state of the diodes; a switching signal generation unit 54 that generates switching signals Qp and Qn by setting the ON interval of the switching element within the range of the synchronous rectification permission intervals Tp and Tn indicated by the corresponding synchronous rectification permission signals Swp and Swn; an assumed permission interval setting unit that sets assumed permission intervals Tp* and Tn* of the synchronous rectification permission signals Swp and Swn based on the operating state of the rotating electric machine 1; and an abnormality determination unit 56 that determines whether or not there is an abnormality by comparing the synchronous rectification permission intervals Tp and Tn with the assumed permission intervals Tp* and Tn*.

A charging system includes a charging input interface, an inductor, a first switch, a second switch, a first voltage acquisition circuit, and a control circuit. The charging input interface is connected to the inductor, which is connected to the first switch and the second switch. The second switch is configured for electrical connection with an energy storage power supply. The first voltage acquisition circuit is connected to the second switch and configured to detect the first voltage output by the charging system in real time. The control circuit cyclically controls the switch on / off time of the first switch based on the first voltage. During the charging process of the charging system, when the first voltage is less than the first preset voltage value, the control circuit controls the first switch to conduct and starts cyclic control. The state of the first switch is opposite to that of the second switch.

A power switching circuit includes a driving signal part, a first switch element, a second switch element, a first driving circuit and a second driving circuit. The first driving circuit includes a first resistor and a first connection branch, which are connected between a positive driving signal terminal of the driving signal part and a first driving terminal of the first switch element, respectively. The second driving circuit includes a third resistor and a second connection branch, which are connected between the positive driving signal terminal and the second driving terminal of the second switch element, respectively. In a same switching cycle, the turn-on time of the first switch element is earlier than the turn-on time of the second switch element and the turn-off time of the first switch element is earlier than the turn-off time of the second switch element.