86 results about "Holding current" patented technology

The invention discloses a flexible interconnection and mode smooth switching method for a distributed power generation system, and relates to the technical field of distributed power generation, and the method comprises the steps: building a droop control relation through continuously collecting DC voltage and current for a source side rectifier of each power generation unit; in a normal mode, the output current of the back-to-back rectifier and the voltage of an intermediate capacitor are collected, the same phase of the current and the load current is kept by using phase locking control, and voltage regulation is realized by combining a dq coordinate model; when a fault of a source side rectifier is detected, an alternating current reference value is generated based on intermediate capacitor voltage deviation and is input into a single current loop controller for voltage stabilization, and meanwhile, a phase advance, adaptive gain and integral saturation resistance mechanism is introduced, so that quick response and stable operation are ensured; in the mode switching process, normal control quantity and fault control quantity are subjected to weighted fusion, and dynamic consistency is achieved through pole matching and reference pre-alignment; the intermediate capacitor voltage fluctuation is significantly reduced, the recovery time is shortened, and the system stability and reliability are improved.

The invention provides an electrostatic powder coating airflow stability real-time compensation method, and relates to the technical field of powder coating control, the method is realized based on an electrostatic powder coating airflow stability real-time compensation device, the device comprises a master control MCU, a pneumatic control valve, a stepping motor driver for driving the pneumatic control valve, and a current sampling circuit coupled to the stepping motor driver, the current collector is used for collecting winding current of the stepping motor in real time. The method comprises the following steps that after a pneumatic control valve is opened to a target opening degree and enters a holding state, a static holding current value of the pneumatic control valve is obtained; comparing the static holding current value with a preset reference holding current value, wherein the preset reference holding current value corresponds to the holding current required by the target opening degree under the smooth state of the airflow channel; according to the offset of the static holding current value relative to the reference holding current value, whether the airflow channel has a blocking trend or not is judged; if not, the current target opening degree of the pneumatic control valve is maintained, the airflow state change can be more directly sensed, and real-time active compensation is carried out.

The invention relates to a new energy grid-connected control technology, in particular to a grid-following type and grid-constructing type dual-mode switching control method and system for a voltage source converter, and the method comprises the steps: building an electrical topology and mathematical model of a grid-connected system, including modeling a main circuit under a synchronous dq coordinate system with a PCC voltage phase angle as a reference, obtaining active P and reactive Q expressions injected into the power grid; under the control of the following network type GFL, a PLL unit, a power outer ring and a current inner ring are adopted to realize synchronization and active / reactive injection control; under the control of the network construction type GFM, a power synchronous ring, an excitation ring, a voltage ring and a current ring are adopted to form network construction control; in the switching process, the current inner ring structure is kept consistent with the reference, when the GFM is switched to the GFL, the output of the power synchronous ring integrator serves as the initial value of the PLL unit integrator, and when the GFL is switched to the GFM, the output of the PLL unit integrator serves as the initial value of the power synchronous ring integrator.

The invention relates to the technical field of mechanical arm control, in particular to a mechanical arm speed control method based on load torque feedforward. The method comprises the following steps: acquiring an angular velocity and a three-phase current of a motor, and performing coordinate transformation to obtain a direct-axis current and a quadrature-axis current; generating a voltage control signal by using a current loop controller; generating a quadrature-axis current reference signal by using a speed ring controller; constructing a load torque observer based on the angular velocity and the quadrature-axis current to estimate the load torque in real time; an acceleration start flag and a deceleration start flag of the motor are detected, the estimated load torque is added to an input of the current loop controller as a feed-forward amount within a first predetermined time after the acceleration start flag is detected, and the feed-forward amount is removed from the input of the current loop controller within a second predetermined time after the deceleration start flag is detected. The constant parameters of the current loop and the speed loop controller are kept when the load and the rotational inertia change, and the stable suppression of the speed fluctuation is realized.

The invention provides a silicon carbide MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) integrated with an SCR (Selective Catalytic Reduction) and a manufacturing method thereof, and relates to the technical field of power semiconductor devices, the device is integrated with a PNPN four-layer structure consisting of a P + region, an N-type epitaxial layer, a P-type body region and an N + source region between a grid electrode and a source electrode, and the P + region is in metal ohmic contact with the source electrode. Through collaborative design of the distance and the doping concentration of the P + region and the N + source region, the forward and reverse trigger voltage thresholds of the PNPN structure can be accurately matched with the asymmetric driving window of the electric control main drive. The structure is arranged on the outer edge of a cellular area or a terminal area, and is electrically isolated from an active area, a field plate is arranged to suppress false triggering, ohmic contact is optimized to accelerate turn-off, and it is ensured that holding current is higher than parasitic latch triggering current, so that rapid and reliable discharge and self-protection of bidirectional surge between a gate and a source are achieved on the premise that the performance of a main device is not affected, and the reliability of the device is improved. And the gate oxide reliability is obviously improved.

The application provides an electrostatic discharge protection device and a chip. The device comprises a substrate, a P-type region and an N-type region in the substrate, a first N-type doped region, a second N-type doped region, a first P-type doped region and a second P-type doped region in the P-type region, the second P-type doped region being between the first N-type doped region and the second N-type doped region, and the first N-type doped region being between the first P-type doped region and the second P-type doped region, a third N-type doped region and a third P-type doped region in the N-type region, and a gate above a region between the first N-type doped region and the second P-type doped region. The gate is connected with the second P-type doped region, the second N-type doped region is connected with the first P-type doped region as a negative electrode of the electrostatic discharge protection device, and the first N-type doped region, the third N-type doped region and the third P-type doped region are connected as a positive electrode of the electrostatic discharge protection device. The application can reduce the triggering voltage of the device and improve the holding current.

The utility model discloses a wide voltage module for an accessory of an alternating current contactor, which comprises the accessory provided with a circuit board. The alternating current and direct current module is used for converting the input alternating current voltage or direct current voltage into correspondingly output direct current voltage; and the input end of the coil driving module is electrically connected with the output end of the alternating current and direct current module. A voltage sampling module outputs a high-level voltage signal or a low-level voltage signal according to an input voltage value, a control module makes a voltage signal for driving an alternating current contactor to be closed or released according to the high-level signal and the low-level signal, and after closing, the control module adjusts the duty ratio, so that a coil driving module only outputs a holding current of 10 mA to 13 mA; according to the scheme, the input AC / DC voltage range is 24V-480V, the size and the cost of the voltage conversion device are reduced, the adaptability of the power supply is improved, and the energy consumption is effectively reduced.

Amplifier (10) with high gain and high tracking speed, comprising: a pair of input transistors (MNP 12, MNN 14) to which input voltages (IN+ and IN-) are applied; a pair of loads switched as diodes (MPP 16, MPN 18) connected to the input transistors (MNP 12, MNN 14); at least a pair of current sources (MPIP 20, MPIN 22) connected to the loads switched as diodes (MPP 16, MPN 18);and a bias control (28) designed to switch off the at least one pair of current sources (MPIP 20, MPIN 22) to enable a high tracking speed for the amplifier (10), wherein the bias control (28) switches off the current sources (MPIP 20, MPIN 22) during a coarse tracking mode of the amplifier (10) when the amplifier (10) is tracking, and to switch on the at least one pair of current sources (MPIP 20, MPIN 22) to enable a high gain for the amplifier (10), and wherein the bias control (28) switches on at least one pair of current sources (MPIP 20, MPIN 22) at the end of the tracking and leaves the current sources (MPIP 20, MPIN 22) switched on when the amplifier (10) is not tracking.

The invention provides a power supply control structure with hot plug and current sharing functions and a control method, the power supply control structure comprises a switching power supply unit, a hot plug power supply module, a central controller and a plurality of electrical parameter acquisition modules, the switching power supply unit comprises a main power supply module and one or more slave power supply modules; the main power supply module and the slave power supply module are used for feeding electric power to a load in an independent or parallel control manner through the corresponding hot plug power supply module, the working mode of the power supply module is adjusted according to the magnitude of the input voltage, and a plug signal of the corresponding hot plug power supply module is started according to the magnitude of the output voltage of the main power supply module. And setting the power supply module to work in a main-standby mode or a current sharing mode according to the output power. According to the invention, rapid response and stability maintenance can be realized when the output voltage changes, and the current stability can be maintained when the load suddenly changes or the input fluctuates, so that the dynamic performance and the protection capability are improved.

The invention relates to an LCC-MMC extra-high-voltage direct-current transmission line fault restarting method and an extra-high-voltage direct-current transmission system, and belongs to the technical field of extra-high-voltage direct-current transmission. When a line fault is detected, the LCC converter station controls the fault current to a direct current reference value; the MMC converter station controls the sub-module voltage to a rated value, the outer loop control output is switched to the sub-module voltage controller output, the direct current bias part of the direct current voltage reference value is switched to the direct current controller output, and the direct current reference value is the direct current reference value; after the deionization time is over, the DC bias part of the MMC converter station rises to a reference value, and the constant current control is quitted at the same time; when the current converter port voltage is detected to be greater than the starting value, the sub-module voltage control is quitted, and the outer loop control output is switched to the direct current voltage controller output; and the LCC converter keeps a current control mode, and when the DC voltage is detected to be greater than a completion value, the LCC converter station switches the current reference value to a real-time current reference value, and the line fault restart is completed.

A load control device for controlling the amount of power delivered from an AC power source to an electrical load is operable to conduct enough current through a thyristor of a connected dimmer switch to exceed rated latching and holding currents of the thyristor. The load control device comprises a controllable-load circuit operable to conduct a controllable-load current through the thyristor of the dimmer switch. The load control device disables the controllable-load circuit when the phase-control voltage received from the dimmer switch is a reverse phase-control waveform. When the phase-control voltage received from the dimmer switch is a forward phase-control waveform, the load control device is operable to decrease the magnitude of the controllable-load current so as to conduct only enough current as is required in order to exceed rated latching and holding currents of the thyristor.

The invention discloses a power regulation and control method and device of an energy storage battery and electronic equipment, and relates to the field of battery management. The method comprises the following steps: monitoring a first state parameter of a battery in real time, and constructing a multi-dimensional state space reflecting electrochemical activity attenuation and thermal runaway risk of the battery according to the first state parameter; wherein the state parameters comprise a thermal diffusion gradient, a polarization voltage abrupt change rate and a gas release rate; dynamically judging whether a power reduction mode is triggered or not according to the multi-dimensional state space; and when the power reduction mode is triggered, carrying out stepped power reduction operation on the battery until the output / input current of the battery is reduced to the load holding current. The technical problem that in the prior art, a single index is adopted for power management and control in battery management, charging and discharging may be stopped too early, and consequently part of actually available capacity cannot be utilized or battery life management is not facilitated is solved.

Valve control (3) for controlling a solenoid valve (2), comprising a control circuit (38) having an input interface (30) for receiving a switching signal and an output interface (31) for coupling a solenoid valve (2), and configured for processing the switching signal and for providing a coil current dependent on the switching signal to the output interface (31), wherein the control circuit (38) is configured to regulate the coil current to a pull-in current during a first time period and to regulate the coil current to a holding current that is less than 70 percent of the pull-in current during a subsequent second time period, wherein the control circuit is configured to increase the holding current by at least 20 percent for a limited time during the second time period if a predetermined coil current threshold is exceeded.wherein the control circuit (38) comprises a microcontroller which is configured to control the coil current during the first time interval and during the second time interval, characterized in that the control circuit (38) is configured such that the percentage increase of the holding current provided for when a predetermined coil current threshold is exceeded is determined by parameterizing the control circuit in order to enable the at least one solenoid valve (2) controlled by the valve control (3) to be adapted to different operating conditions.

The invention relates to a circuit for controlling a current through a relay coil, comprising an electronic switch for controlling the current through the relay coil and a comparator for controlling a control voltage applied to a control terminal of the electronic switch, a first voltage being applied to a first input terminal of the comparator, and a second voltage being applied to a second input terminal of the comparator. A second voltage is applied to the second input of the comparator, said second voltage being derived from the current through the relay coil, and the circuit is designed to reduce the current through the relay coil to a holding current after a switching process caused by a switching current through the relay coil.

To provide a seat belt retractor capable of suppressing power consumption in an electromagnetic lock type configuration.SOLUTION: The seat belt retractor 3 includes the electromagnetic vehicle sensor 40 having the electromagnet 50 and the actuator 60 and configured to switch between the locked state in which the locking mechanism 30 is operated and the unlocked state in which the locking mechanism 30 is not operated by operating the actuator 60 in response to energization of the electromagnet 50, the microswitch 90 as an example of the detection unit configured to detect the operation transition of the actuator 60, and the control unit 100 configured to control the current flowing through the electromagnet 50. A control part 100 switches a current flowing to the electromagnet 50 to a holding current C1 smaller than an operation current C1 when the operation transition of the actuators 60 is detected by the microswitch 90 after the operation current C2 for operating the actuators 60 is made to flow to the electromagnet 50.SELECTED DRAWING: Figure 9

The invention relates to the technical field of railway shunting control technology, and provides a turnout switching state sensing and interlocking control system for flat shunting, a data acquisition module of the turnout switching state sensing and interlocking control system is used for acquiring switch rail displacement voltage signals and switch machine motor current intensity, and calculating a switch rail displacement rate value through a displacement difference value and a time interval at adjacent moments; the conversion pre-judgment module judges a descending trend according to the switch rail displacement rate value and generates a low-frequency holding current instruction and a driving pulse cut-off instruction value; the mechanical verification module collects the displacement reading of the locking rod and the angle of the switch rail to obtain the integrity value of the mechanical structure; the interlocking logic module calls the driving pulse truncation instruction value and the structural integrity value to generate an interlocking state judgment value; and the signal control module outputs a high level to a shunting signal machine lighting circuit according to the interlocking state judgment value to generate a signal open level value. The problems that a mechanical locking structure mostly depends on manual or single-point verification, and linkage of interlocking logic and signal control is weak are solved.

The application provides a static powder coating airflow stability real-time compensation method, relates to the powder coating control technical field, and is realized based on a static powder coating airflow stability real-time compensation device. The device comprises a main control MCU, a gas control valve, a stepping motor driver for driving the gas control valve, a current sampling circuit coupled to the stepping motor driver and used for collecting the winding current of the stepping motor in real time. The method comprises the following steps: after the gas control valve is opened to the target opening degree and enters the holding state, the static holding current value is obtained; the static holding current value is compared with the preset reference holding current value, the preset reference holding current value corresponds to the holding current required by the target opening degree under the unobstructed state of the airflow channel; whether the airflow channel has the blocking trend is judged according to the offset of the static holding current value relative to the reference holding current value; if not, the current target opening degree of the gas control valve is maintained, the airflow state change can be directly sensed, and real-time active compensation can be performed.

The application provides a broken pile detection method and device, electronic equipment and a storage medium, and belongs to the technical field of engineering nondestructive testing. The method comprises the following steps: synchronously acquiring three types of data of holding current, grouting pressure and drill rod vibration at a first acquisition frequency, and calculating the holding current drop amplitude, the grouting pressure drop amplitude and the drill rod vibration frequency growth based on the three types of data. If the above indexes meet the over-limit early warning condition, the current drill rod drilling depth is acquired, and the second acquisition frequency is switched to to supplement the same type of data. The target parameter early warning threshold set is determined based on the soil property data corresponding to the current drilling depth. The three types of data acquired before and after the acquisition and the target parameter early warning threshold set are fused, and the broken pile risk probability is calculated. When the broken pile risk probability reaches the preset broken pile alarm probability threshold, the broken pile alarm information is generated. The application can realize timely identification and accurate early warning of the broken pile risk.

The application discloses a kind of test device and method with the key parameter of electrostatic protection mechanism with back sweep characteristic.The Pwell region, Nc gradually varying capacitance region, Nr resistance region, heavily doped N++, heavily doped N++, Psw region, upper electrode of inversion oxide layer and metal connection constitute the main body of the test device with the key parameter of electrostatic protection mechanism with back sweep characteristic.The application overcomes the defect that minimum back-through voltage and minimum holding current are not easy to measure directly, and can directly measure the minimum back-through voltage and minimum holding current of the electrostatic protection mechanism with back sweep characteristic;It is free from dependence on high-end power semiconductor scanner and TLP test system, and the test equipment used is common basic equipment rather than expensive and complex test equipment;During the test process, voltage and current change are relatively smooth, avoiding the influence of dv / dt, inductance impact, etc., and the measurement result is stable, and the measurement consistency is good.

The invention provides a current-controllable electromagnetic valve drive circuit for EHA and a control method thereof, the current-controllable electromagnetic valve drive circuit comprises an APSOC, a PWM signal conversion module, a drive switch module, a current sampling module, an electromagnetic valve interface module and an inverse peak elimination protection module, high starting current and low work holding current distribution control of an EHA electromagnetic valve is realized, long-time work heating of the electromagnetic valve is reduced, and the service life of the electromagnetic valve is prolonged. The working reliability is improved.

In an aspect, there is provided a method of operating a pulse width modulation (PWM) valve for a fluid application of an agricultural implement. The method includes applying full current for a first period of time to fully open the PWM valve, applying a reduced current for a reduced current value that is from 0 up to a dissipating threshold value that is below full current for a second period of time to rapidly dissipate energy in the PWM valve that is fully open, and applying a holding current for a third period of time to hold the PWM valve fully open for the fluid application.

The present invention relates to a method for controlling a fuel injector (1) of an internal combustion engine with a magnetic actuator (10) for actuating an outwardly opening valve element (4, 6), wherein the magnetic actuator (10) has a magnetic coil (3) and a magnetic armature (2) which is operatively connected to the valve element (4, 6), and the magnetic coil (3) is configured to be supplied with a current in order to open the valve element (4, 6), the method comprising determining a target control end and a target control duration of the magnetic actuator (10) based on a target control start of the magnetic actuator (10) and a target fuel quantity; determining a cylinder pressure expected to act on the valve element (4, 6) at the target control end of the magnetic actuator (10);Determining the expected stroke profile of the valve element (4, 6) during a holding current phase of the solenoid coil (3) as a function of the determined cylinder pressure expected to act on the valve element (4, 6) at the target actuation end. If the expected stroke profile exhibits a maximum stroke of the valve element (4, 6) during the entire holding current phase of the solenoid coil (3), the solenoid actuator (10) is actuated with the determined target actuation duration and the determined target actuation start time. If one or more values ​​of the expected stroke profile during the holding current phase of the solenoid coil (3) are less than the maximum stroke of the valve element (4, 6), the determined target actuation duration and / or the determined target actuation start time are adjusted, and the solenoid actuator (10) is actuated with the adjusted target actuation duration or the adjusted target actuation start time.

The invention provides an electromagnetic valve control method, a braking system, electronic equipment and a vehicle, and relates to the technical field of vehicle control The electromagnetic valve control method comprises the steps that a first preset signal is responded, the holding current of an electromagnetic valve is controlled to be a first preset value so as to open the electromagnetic valve, and the first preset signal represents an instruction for requesting the electromagnetic valve to be powered on; after the holding current of the electromagnetic valve is kept at a first preset value for a first preset duration, the holding current of the electromagnetic valve is controlled to be a second preset value, and the second preset value is smaller than the first preset value; and under the condition that the holding current of the electromagnetic valve is kept at a second preset value and the first preset signal is not received again within a second preset duration, the holding current of the electromagnetic valve is controlled to be a third preset value, and the third preset value is smaller than the second preset value. The problems that in the prior art, an electromagnetic valve used for vehicle braking control is poor in actual application effect, and the driving experience of a user is affected are solved.

The utility model belongs to a ring spinning frame circuit, and particularly relates to a spinning frame power supply protection circuit which comprises a power supply and a band-type brake coil, the band-type brake coil is connected with the power supply, one side of the band-type brake coil is connected with a band-type brake piece, the band-type brake piece brakes a motor of a spinning frame, and a relay contact is connected between the power supply and the band-type brake coil. The relay contact comprises a first contact and a second contact, the first contact is arranged between the positive pole of the power supply and the positive pole of the band-type brake coil, and the second contact is arranged between the negative pole of the band-type brake coil and the negative pole of the power supply; the load side of the relay contact is connected in parallel with a piezoresistor; a filter is arranged between the power supply side of the relay contact and the power supply; the power supply protection circuit is connected with a controller, the controller is arranged on the power supply side of the filter, and a relay coil is arranged between the controller and the power supply protection circuit; according to the utility model, when the relay contact is disconnected, the holding current generated by the band-type brake coil is consumed, so that the power supply is prevented from being damaged.

The invention provides a silicon carbide IGBT integrated with a bidirectional SCR and a manufacturing method thereof, and relates to the technical field of power semiconductor devices. Comprising the steps that a P-type body region, an N + emitter region and a back P + collector region are sequentially formed in an N-type silicon carbide substrate and an N-type epitaxial layer of the N-type silicon carbide substrate, a grid electrode is located above the P-type body region, and an emitter electrode is in ohmic contact with the N + emitter region; a PNPN structure formed by stacking a P + region, an N-type epitaxial layer, a P-type body region and an N + emitter region is integrally integrated between a grid electrode and an emitter electrode to form a bidirectional SCR protection unit, forward and reverse trigger voltage and holding current of the bidirectional SCR protection unit are set through body resistance and doping parameters, the bidirectional SCR protection unit is matched with a grid electrode driving voltage window, and therefore the bidirectional SCR protection unit is formed. And when forward or reverse surge occurs, bidirectional clamping is realized and parasitic latch is suppressed, so that the overvoltage bearing capacity and the working reliability of the gate-emitter end of the silicon carbide IGBT under complex working conditions can be improved.

This invention discloses a DSP-controlled charge pump step-down constant current circuit and its control method, comprising a charge pump module, a current detection module, a feedback loop module, and a DSP control module. The current detection module includes a charging current detection module, a voltage detection module, and a drive module. The feedback loop module includes a voltage divider, a current sensing resistor, a comparator, and an error amplifier. This invention, through the current detection module, feedback loop module, DSP control module, protection mechanism module, and soft-start function, realizes a DSP-controlled charge pump step-down constant current circuit, enabling it to achieve high-precision constant current output. Through real-time calculation and adjustment by the DSP, high-precision control of the output current and voltage is achieved, maintaining current and voltage stability even under load fluctuations. The adaptive frequency control strategy optimizes energy conversion efficiency, reduces energy consumption, and improves flexibility and scalability.

The present invention relates to an energy-saving control method for maintaining a fixed position of an electronic expansion valve, wherein the method includes: self-learning of the holding current, the holding current is set to be adjustable in multiple gears, and when entering the position holding mode, the driving current starts from the maximum holding current, and drops one gear at a time, drops to the minimum holding current and maintains it, during this process, if a change in the Hall signal is detected, the current pressure value is immediately read, the minimum current is set to the previous gear of the holding current gear where the position movement occurs, and then the holding current is set to the maximum holding current, and the above operation is repeated, and the minimum holding current that can maintain the current pressure is found according to the above steps. The present invention also relates to a corresponding system, device, processor and computer-readable storage medium thereof. The method, system, device, processor and computer-readable storage medium thereof of the present invention are used, which have certain accuracy and energy saving effects.

This application provides a method, apparatus, and medium for determining the holding current of a phase-change memory array. The method includes: obtaining the range of set currents for performing a set operation on the phase-change memory array; obtaining the threshold voltage distribution when multiple set currents within the set current range are applied to the phase-change memory array; obtaining the target voltage under each set current based on the standard deviation of a preset multiple of the threshold voltage distribution corresponding to each set current; calculating the voltage difference between the target voltages corresponding to two adjacent set currents within the set current range in the direction of sequential increase of the set current, obtaining multiple voltage differences; and determining the set current corresponding to the voltage difference that satisfies the voltage change condition among the multiple voltage differences as the holding current of the phase-change memory array, thereby achieving simple, fast, accurate, and efficient determination of the holding current of the phase-change memory array.

The utility model relates to a fire extinguishing system and device with low power consumption of a bus, which utilize the unilateral conductivity of a diode, the diode is not conducted without forward voltage difference during standby, and current can pass through normally after voltage difference conduction is generated during short circuit of the bus, so as to control the closing and opening of an isolation relay and carry out isolation protection on an extension module circuit. Circuit devices are few and can be easily added to an extension module circuit, additional isolation modules are not needed, each module can independently achieve isolation protection, on-site construction is more convenient, and the total cost is lower. Aiming at the characteristics of large action current and small holding current of the relay, the capacitor is used for storing energy to maintain standby high voltage so as to instantly provide large current for the relay to maintain the switch of the relay in an off state, the large resistor is used for providing small current to maintain the switch to be off, and the large resistor can also prevent the energy storage capacitor from attenuating alternating current signals on a bus. The power supply current at the moment of relay action is large, the power consumption current during maintenance is small, and the influence on bus alternating current signals is small.

The application discloses a phase change memory and a control method thereof, and belongs to the technical field of memories. The phase change memory comprises a plurality of local word lines and a plurality of local bit lines; a storage unit array comprising a plurality of array-arranged storage units, each storage unit being coupled between a local word line and a local bit line; a plurality of storage units comprising a target storage unit; a first current mirror structure coupled to the target storage unit through a local bit line; and a second current mirror structure coupled to the target storage unit through a local bit line. The first current mirror structure is configured to apply a first current signal to the target storage unit in a first time period; the first current signal is greater than a holding current of the target storage unit. The second current mirror structure is configured to apply a second current signal to the target storage unit in a second time period; the second current signal is greater than the first current signal. The above scheme can reduce the inrush current during the RESET operation.