DC Reverse Step Current Source and its Control Method Based on Real-Time Process Control

Abstract

A DC inverting step current source and its control method based on real-time process control are described. The target value of the inverting step current output by the current source, set by the control target setting module, is converted into an analog voltage by the control signal output module. The control signal adjustment module performs impedance matching on the filtered analog voltage according to the current source's accuracy specifications and outputs an inverting step current to the current sensing resistor based on the analog voltage. The matching impedance of the analog voltage is adjusted so that the voltage across the current sensing resistor equals the analog voltage, and the adjusted inverting step current is output to the current sensing resistor. The digital real-time feedback module converts the feedback voltage across the sampling resistor into the actual value of the inverting step current. The control target setting module compares the deviation between the target value and the actual value of the inverting step current and adjusts the target value according to the built-in adjustment strategy to fulfill the testing requirements of the flexible DC current transformer for the inverting step current.

Description

Technical Field

[0001] This invention belongs to the field of flexible DC transmission technology, specifically, it relates to a DC reversal step current source based on real-time process control and its control method. Background Technology

[0002] When flexible DC uses a multi-stage series configuration, a voltage-equalizing capacitor is connected in parallel between each series-connected IGBT to eliminate overvoltage issues caused by the response time between each stage. The voltage-equalizing capacitor is equivalent to a power supply circuit during a fault. Under line fault conditions, the current direction on the rectifier side remains unchanged. On the inverter side, due to the rapid shut-off of the flexible DC valve group during a short circuit to disconnect the connection between the flexible DC system and the load side, the inverter side becomes a reverse current output provided by the voltage-equalizing capacitor for the short-circuit current, forming a reverse step phenomenon in the flexible DC system. Flexible DC current transformers have repeatedly failed to correctly transmit the step current during reverse step, leading to misjudgments in the control and protection systems. However, the step response tests of flexible DC current transformers are all conducted with a forward current step starting from 0, and rarely involve reverse step tests.

[0003] In existing technologies, switching power supplies use digitally controlled IGBT high-frequency PWM converter modules to turn on and off to output current. Transient step sources modulate three-phase AC power into high-frequency current and then synthesize it into a square wave current source through steep wave technology and compensation current method. Switching power supplies have a single function, and because they use digital control, the waveform is greatly affected by the modulation frequency, resulting in large output current waveform ripple. The top of the output waveform is not easy to stabilize. Switching power amplifiers can only output square wave current and cannot output continuous DC current, nor can they output non-zero starting step current, let alone reverse step current, which cannot meet the reverse step test requirements of flexible DC current transformers. Linear power supplies are independent of the output waveform. They amplify small voltage signals into energy current signals through a high-power power supply. Linear power supplies are arbitrary current waveform generators. In addition to transient step waveforms, high-frequency current waveforms, field fault waveforms, multiple step waveforms, square wave control, overshoot size, and square wave duration can all be configured through software. The power supply has high stability and low ripple content. As long as the output waveform does not exceed the power of the power supply and the frequency range of the power transistor, the waveform will not be distorted. However, when the load is a purely resistive circuit, the power supply is an ideal step source. When the inductance is too large, it will exhibit an oscillating and stabilizing process, and the overshoot and rise time are relative. The circuit inductance is a random parameter, while the power transistor distributed parameter in a linear power supply is a fixed parameter that cannot be reduced. Therefore, the rise time is difficult to reduce under inductive loads. Furthermore, when the reverse step occurs, a power load demand must appear at both ends of the positive and negative power supply. Oscillations will occur at the zero crossing point, making it impossible for the waveform to smoothly cross zero during the reverse step. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a DC reversing step current source and its control method based on real-time process control. The step current source can apply a reversing step current to fulfill the testing requirements of flexible DC current transformers for reversing step current.

[0005] The present invention adopts the following technical solution.

[0006] This invention proposes a DC inverting step current source based on real-time process control. The output terminal of the current source is connected to one end of the load line inductor, and the other end of the load line inductor is connected to zero potential. The current source includes: a control target setting module, a control signal output module, a control signal adjustment module, a current sensing resistor, a sampling resistor, and a digital real-time feedback module; The output of the control target setting module is connected to the input of the control signal output module, and the feedback of the control target setting module is connected to the output of the digital real-time feedback module. The output of the control signal output module is connected to the input of the control signal adjustment module, and the output of the control signal adjustment module is connected to one end of a current sensing resistor. One end of the current sensing resistor is connected to the positive feedback of the control signal adjustment module, and the other end of the current sensing resistor is connected to the negative feedback of the control signal adjustment module and one end of a sampling resistor. The other end of the sampling resistor is connected to one end of the load line inductance. The feedback voltage across the sampling resistor is input to the control target setting module via the digital real-time feedback module. The control target setting module sets the digital signal of the target value of the reverse step current output by the current source. The control signal output module converts the target value of the reverse step current into an analog voltage. The control signal adjustment module performs impedance matching on the filtered analog voltage according to the accuracy index of the current source, and outputs the reverse step current to the current sensing resistor based on the analog voltage. Taking the voltage of the current sensing resistor equal to the analog voltage as the control target, the matching impedance of the analog voltage is adjusted to output the adjusted reverse step current to the current sensing resistor. The digital real-time feedback module converts the feedback voltage across the sampling resistor under the adjusted reverse step current into a digital signal of the actual value of the reverse step current. The control target setting module compares the deviation between the digital signal of the target value of the reverse step current and the digital signal of the actual value of the reverse step current, and adjusts the digital signal of the target value of the reverse step current according to the built-in adjustment strategy.

[0007] Preferably, the control signal conditioning module includes multiple parallel conditioning loops; each conditioning loop includes: a balance conversion unit, a signal processing unit, a precision control unit, a positive and negative power amplification unit, an analog real-time feedback unit, and a compensation capacitor; One end of each adjustment loop is connected to the output terminal of the control signal output module, and the other end of each adjustment loop is connected to one end of the current sensing resistor. In each adjustment loop, the output terminal of the control signal output module is connected to the input terminal of the balance conversion unit, the output terminal of the balance conversion unit is connected to the input terminal of the signal processing unit, the output terminal of the signal processing unit is connected to the input terminal of the precision control unit, the output terminal of the precision control unit is connected to the input terminal of the positive and negative power amplification units, the output terminal of the positive and negative power amplification units is connected to one end of the current sensing resistor, one end of the current sensing resistor is also connected to the positive input terminal of the analog real-time feedback unit, the other end of the current sensing resistor is also connected to the negative input terminal of the analog real-time feedback unit, the output terminal of the analog real-time feedback unit is simultaneously connected to one end of the compensation capacitor and one end of the compensation resistor, the other end of the compensation resistor is connected to the feedback terminal of the precision control unit, and the other end of the compensation capacitor is connected to the equipotential.

[0008] Preferably, the control target setting module is used to set the digital signal of the target value of the reverse step current output by the current source, including: the initial value and the final value of the target value of the reverse step current; the control signal output module is used to convert the initial value and the final value of the target value of the reverse step current into the corresponding analog voltage. The control target setting module includes: an LCD screen and a chip; the chip includes FPGA and ARM; the control signal output module includes: a DA chip; The LCD screen is used for human-computer interaction to set the initial and final values ​​of the target value of the inverted step current; the ARM is used to convert the set initial and final values ​​into corresponding discrete digital signals and pass them to the FPGA; the FPGA transmits the discrete digital signals to the DA chip based on the SPI protocol; the DA chip converts the discrete digital signals into analog voltage signals.

[0009] Preferably, the balanced conversion unit includes: a differential converter; the two output terminals of the DA chip are respectively connected to the positive input terminal and the negative input terminal of the differential converter, and the differential converter is used to convert the differential signal of the analog voltage output by the DA chip into an analog voltage signal referenced to ground; The signal processing unit includes: an RC filter circuit; the signal processing unit is used to filter the analog voltage signal output by the balanced conversion unit; The RC filter circuit includes a first filter resistor, a second filter resistor, and a first capacitor. One end of the first filter resistor is connected to the output terminal of the differential converter. The other end of the first filter resistor is connected to one end of the second filter resistor and one end of the first capacitor. The other end of the first capacitor is grounded. The other end of the second filter resistor is connected to the input terminal of the precision control unit.

[0010] Preferably, the precision control unit is used to perform impedance matching on the filtered analog voltage according to the accuracy index of the current source; the precision control unit includes: a multi-stage operational amplifier; The second filter resistor is connected to the positive input of the first operational amplifier. The negative input of the first operational amplifier is connected to one end of the first resistor and one end of the second resistor. The other end of the first resistor is grounded. The other end of the second resistor is connected to the output of the first operational amplifier and the negative input of the second operational amplifier. The other end of the first resistor is connected to the positive input of the second operational amplifier. The negative power inputs of the second, third, and fourth operational amplifiers are all connected to the same potential. The output of the second operational amplifier is connected to the positive input of the third operational amplifier. The positive power input of the third operational amplifier is connected to one end of the third resistor. The other end of the third resistor is connected to one end of the compensation capacitor. The other end of the compensation capacitor is connected to the same potential. The output of the third operational amplifier is connected to the input of the positive and negative power amplifier units. One end of the compensation capacitor is connected to the output of the analog real-time feedback unit.

[0011] Preferably, the positive and negative power amplification unit includes a positive power amplification subunit and a negative power amplification subunit; when the precision control unit outputs a positive voltage, the positive power amplification subunit operates and the negative power amplification subunit does not operate; when the precision control unit outputs a negative voltage, the negative power amplification subunit operates and the positive power amplification subunit does not operate. The positive power amplifier subunit includes: a first DC power supply, a first amplification resistor, a third amplification resistor, and a first power device. The negative terminal of the first DC power supply is connected to the output terminal of the accuracy control unit. The positive terminal of the first DC power supply is connected to both one end of the first amplification resistor and the base of the first power device. The other end of the first amplification resistor and the collector of the first power device are connected to a high-level signal. The emitter of the first power device is connected to one end of the third amplification resistor, and the other end of the third amplification resistor is connected to a current-sensing resistor. One end; The negative power amplifier subunit includes: a second DC power supply, a second amplification resistor, a fourth amplification resistor, and a second power device. The positive terminal of the second DC power supply is connected to the output terminal of the accuracy control unit, the negative terminal of the second DC power supply is connected to one end of the second amplification resistor and the base of the second power device, the other end of the second amplification resistor and the collector of the second power device are connected to a low level, the emitter of the second power device is connected to one end of the fourth amplification resistor, and the other end of the fourth amplification resistor is connected to one end of the current sensing resistor.

[0012] Preferably, the digital real-time feedback module includes an AD chip; the feedback voltage across the sampling resistor under the adjusted inverted step current is input to the AD chip in a differential manner, the AD chip converts the voltage signal into a digital signal of the actual value of the inverted step current, and transmits the digital signal of the actual value of the inverted step current to the FPGA according to the SPI protocol.

[0013] This invention also proposes a control method for a DC inverting step current source based on real-time process control, comprising: Step 1: Set the digital signal of the target value of the inverted step current output by the current source through the target setting module; the control signal output module converts the target value of the inverted step current into an analog voltage. Step 2: The control signal adjustment module performs impedance matching on the filtered analog voltage according to the accuracy index of the current source, and outputs a reverse step current to the current sensing resistor based on the analog voltage. With the voltage of the current sensing resistor equal to the analog voltage as the control target, the matching impedance of the analog voltage is adjusted to output the adjusted reverse step current to the current sensing resistor. Step 3: The digital real-time feedback module converts the feedback voltage across the sampling resistor under the adjusted reverse step current into a digital signal of the actual value of the reverse step current. Step 4: The control target setting module compares the deviation between the digital signal of the target value of the reverse step current and the digital signal of the actual value of the reverse step current, and adjusts the digital signal of the target value of the reverse step current according to the built-in adjustment strategy.

[0014] Preferably, after setting the initial and final values ​​of the target value of the reversing step current via the LCD screen, the discrete digital signal generated by the ARM... , =0 represents the step jump moment; Establish an RLC oscillation circuit for the current source and load line, and determine the transfer function of the RLC oscillation circuit; Based on the transfer function of the RLC oscillator circuit, calculate the rise time, step overshoot, and stabilization time of the actual value of the reverse step current. When the rise time is greater than the specified value, When ≥0, set a negative infinity feedback voltage signal. ,exist Set feedback voltage signal when <0 The value is 0; the inverted step current signal output by the control signal conditioning module is... = + ; When the step overshoot exceeds a specified value, the feedback compensation signal for the discrete digital signal generated by the ARM is determined based on the relationship between the sum of the actual value and the differential value of the reversing step current and the magnitude of the negative analog voltage. ,in, The feedback time of the current source; The inverted step current signal output by the current source is + .

[0015] Preferably, the discrete digital signal is as follows: = , <0 = , ≥0 In the formula, It is a discrete digital signal. , These are the analog voltages corresponding to the initial and final values ​​of the target value of the reversing step current, respectively. This is a positive analog voltage. It is a negative analog voltage. =0 represents the step jump moment.

[0016] Preferably, the feedback voltage signal satisfies the following relationship: =0, <0 = , ≥0.

[0017] Preferably, the actual value of the reversing step current The single-point differential value is ,in, For the first Each sample value, For the first -1 sample value; feedback compensation signal As shown in the following formula: =A, +3 <

[0018] =0, +3 ≥

[0019] In the formula, Let A be the feedback time of the current source. × , This is to allow time for things to stabilize.

[0020] The present invention is also a terminal, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to perform operations according to the instructions to execute the steps of the method.

[0021] The present invention is also a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method.

[0022] The beneficial effects of this invention are as follows: Compared with the prior art, the proposed DC inverting step current source adopts an integrated design, arranging the control system and actuator in the same chassis, facilitating on-site portability and operation. Each adjustment loop uses power transistor closed-loop feedback for real-time physical adjustment, ensuring the output accuracy of the single transistor current and the smooth zero-crossing of the inverting step. Multiple adjustment loops with consistent response times are connected in parallel to achieve a large current step response output. The inverting step can double the step response output capability. A push-pull operating mode is adopted, ensuring that the positive and negative power transistors do not operate simultaneously; when not operating, they only provide a small static leakage current, improving the overall system efficiency. The current source has a built-in sampling resistor connected in series with the current output loop, and uses an AD chip with differential input for digital-to-analog conversion, realizing digital overall closed-loop feedback regulation and control. Infinite output is used at the initial step, fully releasing the response capability of the power amplifier transistor and significantly improving the rise time of the step response. Feedback regulation with lead differential control effectively suppresses overshoot current in the overall loop. A feedback control signal with attenuation effectively prevents system oscillation due to unreasonable lead. Attached Figure Description

[0023] Figure 1 This is a circuit diagram of a DC inverting step current source based on real-time process control proposed in this invention; the reference numerals in the figure are explained as follows: 10-Control target setting module, 11-Control signal output module, 12-Balance conversion unit, 13-Signal processing unit, 14-Precision control unit, 15-Positive and negative power amplification unit, 16-Analog real-time feedback unit, 17-Digital real-time feedback module, 20-Control signal adjustment module; Figure 2 This is one of the partial circuit diagrams of the current source in the embodiments of the present invention, including a control target setting module, a control signal output module, a balance conversion unit, and a digital real-time feedback module; Figure 3 This is a second partial circuit diagram of the current source in an embodiment of the present invention, including a signal processing unit and a precision control unit; Figure 4 This is the third partial circuit diagram of the current source in the embodiment of the present invention, including positive and negative power amplification units and analog real-time feedback units; Figure 5 This is a control principle diagram of the digital signal that adjusts the target value of the reverse step current according to the built-in adjustment strategy proposed in this invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0025] This invention proposes a DC inverting step current source based on real-time process control, wherein the output terminal of the current source is connected to the load line inductance. One end, load line inductance The other end is connected to zero potential, such as Figure 1 As shown, the current source includes: a control target setting module 10, a control signal output module 11, a control signal adjustment module 20, and a current sensing resistor. Sampling resistor and digital real-time feedback module 17; Specifically, the output of the control target setting module is connected to the input of the control signal output module, and the feedback of the control target setting module is connected to the output of the digital real-time feedback module; the output of the control signal output module is connected to the input of the control signal adjustment module, the output of the control signal adjustment module is connected to one end of the current sensing resistor, one end of the current sensing resistor is connected to the positive feedback of the control signal adjustment module, the other end of the current sensing resistor is connected to the negative feedback of the control signal adjustment module and one end of the sampling resistor, and the other end of the sampling resistor is connected to one end of the load line inductance; the feedback voltage across the sampling resistor... The data is input to the control target setting module via the digital real-time feedback module; The control target setting module sets the digital signal of the target value of the reverse step current output by the current source. The control signal output module converts the initial and final values ​​of the target value of the reverse step current into an analog voltage. The control signal adjustment module performs impedance matching on the filtered analog voltage according to the accuracy index of the current source, and outputs the reverse step current to the current sensing resistor based on the analog voltage. Taking the voltage of the current sensing resistor equal to the analog voltage as the control target, the matching impedance of the analog voltage is adjusted to output the adjusted reverse step current to the current sensing resistor. The digital real-time feedback module converts the feedback voltage across the sampling resistor under the adjusted reverse step current into a digital signal of the actual value of the reverse step current. The control target setting module compares the deviation between the digital signal of the target value of the reverse step current and the digital signal of the actual value of the reverse step current, and adjusts the digital signal of the target value of the reverse step current according to the built-in adjustment strategy.

[0026] In the DC reverse step current source proposed in this invention, the target value of the reverse step current can be dynamically adjusted according to the actual output deviation, forming a closed-loop structure of analog and digital dual loops: target → output → feedback → target adjustment → re-output. Furthermore, the real-time process control requirements are built into the adjustment strategy, realizing a deep integration of electrical parameter adjustment and process control. To achieve more refined adjustment, an outer loop control for current accuracy, a middle loop control for voltage matching, and an inner loop control for the adjustment strategy are introduced, significantly improving the output accuracy of the current source, shortening the rise time of the step response current, and avoiding the occurrence of overshoot current during the step response control process.

[0027] The control signal conditioning module includes multiple parallel conditioning loops; each conditioning loop includes: a balance conversion unit 12, a signal processing unit 13, a precision control unit 14, a positive and negative power amplification unit 15, an analog real-time feedback unit 16, and a compensation capacitor. ; One end of each adjustment loop is connected to the output terminal of the control signal output module, and the other end of each adjustment loop is connected to one end of the current sensing resistor. In each adjustment loop, the output terminal of the control signal output module is connected to the input terminal of the balance conversion unit, the output terminal of the balance conversion unit is connected to the input terminal of the signal processing unit, the output terminal of the signal processing unit is connected to the input terminal of the precision control unit, the output terminal of the precision control unit is connected to the input terminal of the positive and negative power amplification units, the output terminal of the positive and negative power amplification units is connected to one end of the current sensing resistor, one end of the current sensing resistor is also connected to the positive input terminal of the analog real-time feedback unit, the other end of the current sensing resistor is also connected to the negative input terminal of the analog real-time feedback unit, the output terminal of the analog real-time feedback unit is simultaneously connected to one end of the compensation capacitor and one end of the compensation resistor, the other end of the compensation resistor is connected to the feedback terminal of the precision control unit, and the other end of the compensation capacitor is connected to the equipotential.

[0028] In this embodiment, each adjusted analog voltage is 2V, and when the current sensing resistor is 0.1Ω, each drive current is 20A; for 40 sets of parallel adjustment loops, the total drive current is 800A, and the feedback voltage is obtained after passing through a sampling resistor with a resistance of 0.002Ω. The voltage is 1.6V. If a control voltage of 2V corresponds to 800A, then a single transistor with a 100mΩ current sensing resistor outputs 20A, and 40 groups connected in parallel ultimately output 800A. Because the response times of the 40 parallel power transistors differ, meaning the real-time feedback response time cannot be guaranteed, the step response rise time becomes longer. Therefore, a sampling resistor is configured in the 800A output circuit based on the original feedback loop. For example, when the sampling resistor is 2mΩ, the feedback voltage is 1.6V. This establishes a feedback control system with the 40 power transistors as the total current signal, implemented in software.

[0029] Specifically, the control target setting module is used to set the digital signal of the target value of the reverse step current output by the current source, including: the initial value and the final value of the target value of the reverse step current; In the embodiments, such as Figure 2 As shown, the control target setting module includes, but is not limited to: a touch LCD screen and a ZYNQ chip. The touch LCD screen and the chip are connected via an external bus. The chip includes, but is not limited to: an FPGA and an ARM core. The FPGA and the ARM core are connected via an internal bus. The touch LCD screen is used for human-machine interaction, setting the initial and final values ​​of the inverting step current target value. The ARM core is used to convert the set control target value into corresponding discrete digital values ​​and pass them to the FPGA chip in the ZYNQ chip for further processing. The FPGA transmits the discrete digital values ​​to the control signal output module based on the SPI protocol. Using the ZYNQ chip is a non-limiting but preferred choice, as it is an FPGA+ARM dual-processor architecture, using a high-temperature stable crystal oscillator (OCXO) as the clock for the entire system, with a frequency accuracy level of up to 5ppm.

[0030] Specifically, the control signal output module is used to convert the initial and final values ​​of the target value of the inverted step current into the corresponding analog voltage; In the embodiments, such as Figure 2 As shown, the control signal output module includes, but is not limited to: a DA chip; the FPGA is responsible for sending the initial and final values ​​of the target value of the inverted step current, which is represented as a discrete digital signal, to the DA chip according to the SPI protocol; the DA chip is responsible for converting the digital discrete signal into an analog small voltage signal; the DA chip is a 16-bit DA chip with a signal output range of ±10V, and the sampling output frequency of 1MHz is selected according to the frequency and accuracy curve of the chip.

[0031] Specifically, the balance conversion unit is used to convert the differential signal of the analog voltage output by the control signal output module into an analog voltage signal referenced to ground; In the embodiments, such as Figure 2 As shown, the balanced conversion unit includes, but is not limited to: a differential converter; the two output terminals of the DA chip are respectively connected to the positive and negative input terminals of the differential converter, and the differential converter is used to convert the differential signal of the analog voltage output by the DA chip into a differential signal. It is converted into an analog voltage signal for reference to ground.

[0032] Specifically, the signal processing unit is used to filter the analog voltage signal to reduce the impact of common-mode noise on the power amplifiers in the positive and negative power amplification units under strong interference environment of the power system. In the embodiments, such as Figure 3 As shown, the signal processing unit includes, but is not limited to: an RC filter circuit; the RC filter circuit includes a first filter resistor. 2nd filter resistor and the first capacitor One end of the first filter resistor is connected to the output of the differential converter, and the other end of the first filter resistor is connected to one end of the second filter resistor and one end of the first capacitor. The other end of the first capacitor is grounded, and the other end of the second filter resistor is connected to the input of the precision control unit. Specifically, the precision control unit is used to perform impedance matching on the filtered analog voltage according to the accuracy specifications of the current source; In the embodiments, such as Figure 3 As shown, the precision control unit includes, but is not limited to: multi-stage operational amplifiers, each stage of which has ultra-low zero drift and ultra-low temperature drift characteristics; the other end of the second filter resistor is connected to the first-stage operational amplifier. The positive input terminal, the first stage operational amplifier The negative input terminal is connected to the first resistor. one end and the second resistor One end, the first resistor The other end is grounded, the second resistor The other end is connected to the first stage operational amplifier. The output terminal and the second stage operational amplifier The negative input terminal, the first resistor The other end is connected to the second-stage operational amplifier. The positive input terminal, the second stage operational amplifier The negative input terminal of the power supply, the third operational amplifier The negative input terminal and the third operational amplifier The negative input terminals of the power supply are all connected to the same potential. The second-stage operational amplifier... The output terminal is connected to the third operational amplifier. The positive input terminal, the third operational amplifier The positive input terminal of the power supply is connected to the third resistor. One end, the third resistor The other end is connected to a compensation capacitor. One end, compensation capacitor The other end is connected to the same potential, the third stage operational amplifier. The output terminal is connected to the input terminal of the positive and negative power amplifier units, and the compensation capacitor... One end is connected to the output of the analog real-time feedback unit. Utilizing the operating characteristics of a multi-stage operational amplifier, impedance matching of the filtered analog voltage can be performed according to the current source accuracy specifications, thereby ensuring that the subsequent output inverting step current meets the current source accuracy specifications.

[0033] Specifically, the positive and negative power amplification unit includes a positive power amplification subunit and a negative power amplification subunit; when the precision control unit outputs a positive voltage, the positive power amplification subunit operates and the negative power amplification subunit does not operate; when the precision control unit outputs a negative voltage, the negative power amplification subunit operates and the positive power amplification subunit does not operate; the positive and negative power amplification units output a reverse step current to the current sensing resistor; In the embodiments, such as Figure 4 As shown, the positive power amplifier subunit includes: a first DC power supply. First amplifying resistor 3rd Amplifying Resistor and the first power device In this configuration, the negative terminal of the first DC power supply is connected to the output terminal of the precision control unit, the positive terminal of the first DC power supply is connected to both one end of the first amplifying resistor and the base of the first power device, and the other end of the first amplifying resistor and the collector of the first power device are connected to a high-level signal. The emitter of the first power device is connected to one end of the third amplifying resistor, and the other end of the third amplifying resistor is connected to the current sensing resistor. One end; in the embodiment, the first power device is an NPN-level MOS power device; The negative power amplifier subunit includes: a second DC power supply. 2nd Amplifying Resistor 4th amplifying resistor and the second power device In this configuration, the positive terminal of the second DC power supply is connected to the output terminal of the precision control unit, the negative terminal of the second DC power supply is connected to both one end of the second amplifying resistor and the base of the second power device, and the other end of the second amplifying resistor and the collector of the second power device are connected to a low-level signal. The emitter of the second power device is connected to one end of the fourth amplifying resistor, and the other end of the fourth amplifying resistor is connected to the current sensing resistor. One end; in the embodiment, the second power device is a PNP-level MOS power device; like Figure 4 As shown, the simulated real-time feedback unit includes a feedback resistor. and the 4th operational amplifier Among them, current sensing resistor One end is connected to the fourth stage operational amplifier. Positive input terminal, current sensing resistor The other end is connected to the fourth operational amplifier. The negative input terminal, the fourth operational amplifier The output terminal is connected to a feedback resistor. One end, feedback resistor The other end is connected to a compensation capacitor. One end; The delay parameters of the first and second power devices are the same. Since the positive and negative power amplifier modules are actually parallel structures of multiple power devices, NPN and PNP MOS power devices with the same delay parameters are selected as much as possible to ensure the consistency of the step response characteristics. However, in reality, the parameters of each power transistor are not completely identical. During the step response, the inconsistent response time can cause a very large overshoot in one of the power transistors, resulting in damage to a single transistor in the first or second power device. Therefore, a compensation capacitor is configured in the analog real-time feedback unit. Current suppression and capacitor compensation. One end is connected to an additional pin of the operational amplifier on the output side of the precision control module via a compensation resistor; the compensation capacitor filters the clamping voltage to prevent damage to the power transistor due to excessive overshoot during the feedback process.

[0034] In practice, the precision control unit uses the input voltage of the operational amplifier to clamp the voltage across the current-sensing resistor, thereby ensuring that the conduction current on the current-sensing resistor is the target control current. This achieves a control strategy that adjusts the matching impedance of the analog voltage by making the voltage across the current-sensing resistor equal to the analog voltage. High-precision, low-temperature drift, non-inductive current-sensing resistors are used. In this embodiment, having the number of current-sensing resistors equal to the number of parallel regulating loops is a non-limiting but preferred choice, with one current-sensing resistor corresponding to each regulating loop.

[0035] This invention employs a single-power transistor closed-loop feedback real-time physical adjustment to ensure the output accuracy of the single-transistor current and the smooth zero-crossing of the inverting step. It utilizes parallel output of multiple transistors with consistent response times to achieve a high-current step response output. The inverting step can double the step response output capability. Employing a push-pull operating mode, the positive and negative power transistors do not operate simultaneously; when not operating, they only provide a small static leakage current, improving the overall system efficiency. Utilizing the operating characteristics of the push-pull power transistors, the step response capability during inverting step is determined by the response time of the positive and negative power transistors. The feedback clamping of the transistor across the current sensing resistor ensures the output accuracy of the single transistor. With the same signal driving both positive and negative power transistors, only one transistor can be in the conducting state, thus ensuring a smooth zero-crossing. Parallel connection of multiple transistors ensures the consistency of the high current, and the switching of two transistors in microseconds doubles the step response output capability.

[0036] Specifically, the sampling resistor is used to convert a large current signal into a small voltage signal; in this embodiment, the sampling resistor is a high-power linear non-inductive resistor, and the voltage across the sampling resistor is a small voltage signal. .

[0037] Specifically, the digital real-time feedback module includes an AD chip; the feedback voltage across the sampling resistor under the adjusted inverted step current is input to the AD chip in a differential manner, and the AD chip converts the voltage signal into a digital signal of the actual value of the inverted step current. In this embodiment, the AD chip is responsible for converting small voltage signals into real-time digital signals and sending the real-time digital signals to the FPGA according to the SPI protocol. The A / D acquisition chip uses the AD7690 18-bit chip from Analog Devices, which is a differential ADC with a specification of 1.5 LSBINL and 400 k SPS. Its differential input characteristics have stronger anti-interference performance. The sampling input frequency is 1MHz.

[0038] The current source proposed in this invention has a built-in sampling resistor connected in series with the current output circuit, and uses an AD chip with differential input for digital-to-analog conversion, realizing digital overall closed-loop feedback regulation and control. This invention employs feedback regulation with lead differential control to effectively suppress overshoot current in the overall circuit; and uses a feedback control signal with attenuation to effectively prevent system oscillation due to unreasonable lead.

[0039] This invention proposes a DC inverting step current source based on real-time process control, which is a high-current inverting step DC source with both analog and digital feedback. The current source consists of control target setting, control signal output, balance conversion and signal processing, accuracy assurance, positive and negative power amplification and current sensing resistors, load, analog real-time feedback, compensation capacitors, and digital real-time feedback. It adopts an integrated design, with all the above modules installed in a single chassis. To address heat dissipation, the power supply module is independent and equipped with a dedicated heat dissipation module to improve the long-term reliability of the current source. The control system and the actuator (power amplification module) are arranged in the same chassis for easy on-site portability and operation.

[0040] This invention also proposes a control method for a DC inverting step current source based on real-time process control, comprising: Step 1: Set the digital signal of the target value of the reverse step current output by the current source through the target setting module; the control signal output module converts the initial and final values ​​of the target value of the reverse step current into analog voltage.

[0041] In this embodiment, after setting the initial and final values ​​of the target reverse step current via the LCD screen, the ARM generates a step response function and discretizes it to obtain a discrete digital signal, which is then sent to the FPGA for preprocessing. The discrete digital signal is shown in the following equation: = , <0 = , ≥0 In the formula, It is a discrete digital signal. , These are the analog voltages corresponding to the initial and final values ​​of the target value of the reversing step current, respectively. This is a positive analog voltage. It is a negative analog voltage. =0 represents the step jump moment; The reversal phase is achieved by setting initial and final values ​​for the target value.

[0042] Step 2: The control signal adjustment module performs impedance matching on the filtered analog voltage according to the accuracy index of the current source, and outputs a reverse step current to the current sensing resistor based on the analog voltage. With the voltage of the current sensing resistor equal to the analog voltage as the control target, the matching impedance of the analog voltage is adjusted to output the adjusted reverse step current to the current sensing resistor.

[0043] Step 3: The digital real-time feedback module converts the feedback voltage across the sampling resistor under the adjusted reverse step current into a digital signal of the actual value of the reverse step current.

[0044] Step 4: The control target setting module compares the deviation between the digital signal of the target value of the reverse step current and the digital signal of the actual value of the reverse step current, and adjusts the digital signal of the target value of the reverse step current according to the built-in adjustment strategy.

[0045] The control target setting module compares the deviation between the digital signal of the target value of the reverse step current and the digital signal of the actual value of the reverse step current. When the deviation is less than 1% of the target value of the reverse step current, the digital signal of the target value of the reverse step current is adjusted according to the built-in adjustment strategy. Specifically, step 4 includes: Step 4.1: Establish the RLC oscillation circuit of the current source and load line, and determine the transfer function of the RLC oscillation circuit; The initial value of the reverse step current is set to infinite output, which fully releases the response capability of the power amplifier tube and significantly improves the rise time of the step response. The current source operates in short-circuit mode, so the optimal output mode is zero-inductance mode. During field testing, the test wires serve as the load. Due to the uncontrollable length of the wires and the wiring method, the inductance parameters of the line are uncertain.

[0046] Since current cannot change abruptly, the actual load is a conductor several meters long, primarily exhibiting inductive characteristics. The equivalent inductance of the load circuit, along with the current sensing resistor, sampling resistor, matching impedance of the precision control unit, compensation capacitor, and distributed capacitance within the power transistor, collectively constitutes the RLC oscillation circuit. This application... Therefore, it is necessary to analyze the RLC oscillator circuit to determine the resonant angular frequency. = Attenuation factor = and time constant = = In the formula, , These are the equivalent inductance and equivalent resistance of the RLC oscillator circuit, respectively.

[0047] when > When the circuit is in an overdamped state, the transfer function of the RLC oscillator circuit is... for: =1- , ≥0 When 0 < < When the circuit is in an underdamped state, the transfer function of the RLC oscillator circuit is... for: =1- , ≥0 =

[0048] In the formula, The damping coefficient is... This is the natural oscillation frequency.

[0049] The transfer function of the RLC oscillator circuit transforms the physical circuit into a mathematical object, making the transfer function a core tool for the design and analysis of the built-in regulation strategy in the control target setting module.

[0050] Step 4.2: Based on the transfer function of the RLC oscillator circuit, calculate the rise time, step overshoot, and stabilization time of the actual value of the reverse step current. Specifically, the rise time is the time it takes for the initial step value to reach the final step value; the step overshoot is the ratio of the difference between the current peak value and the final step value to the final step value; and the stabilization time is the time it takes for the difference between the real-time current value and the final step value to be less than 1.5% over a continuous period of time. These three indicators are the main technical specifications of the DC reversing step current source.

[0051] Step 4.3, when the rise time is greater than the corresponding specified value, in When the value is ≥0, a negative infinite feedback voltage signal is set to accelerate the rise of the step response, satisfying the following relationship: =0, <0 = , ≥0 The inverted step current signal output by the control signal conditioning module is shown in the following formula: = +

[0052] Step 4.4: When the step overshoot exceeds the corresponding specified value, determine the discrete digital signal based on the relationship between the sum of the actual value and the differential value of the reversing step current and the magnitude of the negative analog voltage. Feedback compensation signal ; Feedback will inevitably produce a large overshoot. The entire system's AD sampling rate is 1MHz, and the DA output sampling rate is also 1MHz. At this time, the control feedback time of the entire system is... 3 If overshoot suppression is performed based on the feedback signal, the overshoot is already very large, so an advance is required. This invention proposes to differentiate the step response signal and then use PD regulation to provide an advance control strategy for the step signal.

[0053] Actual value of reverse step current The single-point differential value is ,in, For the first Each sample value, For the first -1 sample value; feedback compensation signal As shown in the following formula: =A, +3 <

[0054] =0, +3 ≥

[0055] In the formula, Let A be the feedback time of the current source. × To prevent oscillations in the step response system, the value of A includes a damping coefficient.

[0056] It is worth noting that the specified values ​​for rise time and step overshoot are determined through performance testing of the relevant products.

[0057] Step 4.5, the inverted step current signal output by the current source is: + .

[0058] In the embodiments, the logic of the digital signal that adjusts the target value of the reversing step current according to the built-in adjustment strategy proposed in this invention is as follows: Figure 5 As shown, discrete digital signals The inverted step current signal after feedback regulation of the DA output by the control signal conditioning module , The output signal is amplified by multiple transistors in parallel and then sampled by an AD converter. - Current feedback voltage signal at time , It is a feedback compensation signal with sampling advance.

[0059] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0060] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0061] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0062] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A DC inverting step current source based on real-time process control, wherein the output terminal of the current source is connected to one end of the load line inductance, and the other end of the load line inductance is connected to zero potential; characterized in that, include: The system includes a control target setting module, a control signal output module, a control signal adjustment module, a current sensing resistor, a sampling resistor, and a digital real-time feedback module. The output of the control target setting module is connected to the input of the control signal output module, and the feedback of the control target setting module is connected to the output of the digital real-time feedback module. The output of the control signal output module is connected to the input of the control signal adjustment module, and the output of the control signal adjustment module is connected to one end of a current sensing resistor. One end of the current sensing resistor is connected to the positive feedback of the control signal adjustment module, and the other end of the current sensing resistor is connected to the negative feedback of the control signal adjustment module and one end of a sampling resistor. The other end of the sampling resistor is connected to one end of the load line inductance. The feedback voltage across the sampling resistor is input to the control target setting module via the digital real-time feedback module. The control target setting module sets the digital signal of the target value of the reverse step current output by the current source. The control signal output module converts the target value of the reverse step current into an analog voltage. The control signal adjustment module performs impedance matching on the filtered analog voltage according to the accuracy index of the current source, and outputs the reverse step current to the current sensing resistor based on the analog voltage. Taking the voltage of the current sensing resistor equal to the analog voltage as the control target, the matching impedance of the analog voltage is adjusted to output the adjusted reverse step current to the current sensing resistor. The digital real-time feedback module converts the feedback voltage across the sampling resistor under the adjusted reverse step current into a digital signal of the actual value of the reverse step current. The control target setting module compares the deviation between the digital signal of the target value of the reverse step current and the digital signal of the actual value of the reverse step current, and adjusts the digital signal of the target value of the reverse step current according to the built-in adjustment strategy.

2. The DC reversing step current source based on real-time process control according to claim 1, characterized in that, The control signal conditioning module includes multiple parallel conditioning loops; each conditioning loop includes: a balance conversion unit, a signal processing unit, a precision control unit, a positive and negative power amplification unit, an analog real-time feedback unit, and a compensation capacitor; One end of each adjustment loop is connected to the output terminal of the control signal output module, and the other end of each adjustment loop is connected to one end of the current sensing resistor. In each adjustment loop, the output terminal of the control signal output module is connected to the input terminal of the balance conversion unit, the output terminal of the balance conversion unit is connected to the input terminal of the signal processing unit, the output terminal of the signal processing unit is connected to the input terminal of the precision control unit, the output terminal of the precision control unit is connected to the input terminal of the positive and negative power amplification units, the output terminal of the positive and negative power amplification units is connected to one end of the current sensing resistor, one end of the current sensing resistor is also connected to the positive input terminal of the analog real-time feedback unit, the other end of the current sensing resistor is also connected to the negative input terminal of the analog real-time feedback unit, the output terminal of the analog real-time feedback unit is simultaneously connected to one end of the compensation capacitor and one end of the compensation resistor, the other end of the compensation resistor is connected to the feedback terminal of the precision control unit, and the other end of the compensation capacitor is connected to the equipotential.

3. The DC reversing step current source based on real-time process control according to claim 2, characterized in that, The control target setting module is used to set the digital signal of the target value of the reverse step current output by the current source, including: the initial value and the final value of the target value of the reverse step current; the control signal output module is used to convert the initial value and the final value of the target value of the reverse step current into the corresponding analog voltage. The control target setting module includes: an LCD screen and a chip; the chip includes FPGA and ARM; the control signal output module includes: a DA chip; The LCD screen is used for human-computer interaction to set the initial and final values ​​of the target value of the inverted step current; the ARM is used to convert the set initial and final values ​​into corresponding discrete digital signals and pass them to the FPGA; the FPGA transmits the discrete digital signals to the DA chip based on the SPI protocol; the DA chip converts the discrete digital signals into analog voltage signals.

4. The DC reversing step current source based on real-time process control according to claim 3, characterized in that, The balanced conversion unit includes: a differential converter; the two output terminals of the DA chip are respectively connected to the positive input terminal and the negative input terminal of the differential converter, and the differential converter is used to convert the differential signal of the analog voltage output by the DA chip into an analog voltage signal referenced to ground; The signal processing unit includes: an RC filter circuit; the signal processing unit is used to filter the analog voltage signal output by the balanced conversion unit; The RC filter circuit includes a first filter resistor, a second filter resistor, and a first capacitor. One end of the first filter resistor is connected to the output terminal of the differential converter. The other end of the first filter resistor is connected to one end of the second filter resistor and one end of the first capacitor. The other end of the first capacitor is grounded. The other end of the second filter resistor is connected to the input terminal of the precision control unit.

5. The DC reversing step current source based on real-time process control according to claim 4, characterized in that, The precision control unit is used to impedance match the filtered analog voltage according to the accuracy specifications of the current source; the precision control unit includes: a multi-stage operational amplifier; The second filter resistor is connected to the positive input of the first operational amplifier. The negative input of the first operational amplifier is connected to one end of the first resistor and one end of the second resistor. The other end of the first resistor is grounded. The other end of the second resistor is connected to the output of the first operational amplifier and the negative input of the second operational amplifier. The other end of the first resistor is connected to the positive input of the second operational amplifier. The negative power inputs of the second, third, and fourth operational amplifiers are all connected to the same potential. The output of the second operational amplifier is connected to the positive input of the third operational amplifier. The positive power input of the third operational amplifier is connected to one end of the third resistor. The other end of the third resistor is connected to one end of the compensation capacitor. The other end of the compensation capacitor is connected to the same potential. The output of the third operational amplifier is connected to the input of the positive and negative power amplifier units. One end of the compensation capacitor is connected to the output of the analog real-time feedback unit.

6. The DC inverting step current source based on real-time process control according to claim 5, characterized in that, The positive and negative power amplification unit includes a positive power amplification subunit and a negative power amplification subunit. When the precision control unit outputs a positive voltage, the positive power amplification subunit operates and the negative power amplification subunit does not operate. When the precision control unit outputs a negative voltage, the negative power amplification subunit operates and the positive power amplification subunit does not operate. The positive power amplifier subunit includes: a first DC power supply, a first amplification resistor, a third amplification resistor, and a first power device. The negative terminal of the first DC power supply is connected to the output terminal of the accuracy control unit. The positive terminal of the first DC power supply is connected to both one end of the first amplification resistor and the base of the first power device. The other end of the first amplification resistor and the collector of the first power device are connected to a high-level signal. The emitter of the first power device is connected to one end of the third amplification resistor, and the other end of the third amplification resistor is connected to a current-sensing resistor. One end; The negative power amplifier subunit includes: a second DC power supply, a second amplification resistor, a fourth amplification resistor, and a second power device. The positive terminal of the second DC power supply is connected to the output terminal of the accuracy control unit, the negative terminal of the second DC power supply is connected to one end of the second amplification resistor and the base of the second power device, the other end of the second amplification resistor and the collector of the second power device are connected to a low level, the emitter of the second power device is connected to one end of the fourth amplification resistor, and the other end of the fourth amplification resistor is connected to one end of the current sensing resistor.

7. The DC reversing step current source based on real-time process control according to claim 3, characterized in that, The digital real-time feedback module includes an AD chip; the feedback voltage across the sampling resistor under the adjusted inverted step current is input to the AD chip in a differential manner. The AD chip converts the voltage signal into a digital signal of the actual value of the inverted step current, and transmits the digital signal of the actual value of the inverted step current to the FPGA according to the SPI protocol.

8. A control method for a DC inverting step current source based on real-time process control, applicable to the DC inverting step current source based on real-time process control as described in any one of claims 1 to 7; characterized in that, include: Step 1: Set the digital signal of the target value of the inverted step current output by the current source through the target setting module; the control signal output module converts the target value of the inverted step current into an analog voltage. Step 2: The control signal adjustment module performs impedance matching on the filtered analog voltage according to the accuracy index of the current source, and outputs a reverse step current to the current sensing resistor based on the analog voltage. With the voltage of the current sensing resistor equal to the analog voltage as the control target, the matching impedance of the analog voltage is adjusted to output the adjusted reverse step current to the current sensing resistor. Step 3: The digital real-time feedback module converts the feedback voltage across the sampling resistor under the adjusted reverse step current into a digital signal of the actual value of the reverse step current. Step 4: The control target setting module compares the deviation between the digital signal of the target value of the reverse step current and the digital signal of the actual value of the reverse step current, and adjusts the digital signal of the target value of the reverse step current according to the built-in adjustment strategy.

9. The control method for a DC inverting step current source based on real-time process control according to claim 8, characterized in that, After setting the initial and final values ​​of the inverted step current target value via the LCD screen, the discrete digital signal generated by the ARM is... , =0 represents the step jump moment; Establish an RLC oscillation circuit for the current source and load line, and determine the transfer function of the RLC oscillation circuit; Based on the transfer function of the RLC oscillator circuit, calculate the rise time, step overshoot, and stabilization time of the actual value of the reverse step current. When the rise time is greater than the specified value, When ≥0, set a negative infinity feedback voltage signal. ,exist Set feedback voltage signal when <0 The value is 0; the inverted step current signal output by the control signal conditioning module is... = + ; When the step overshoot exceeds a specified value, the feedback compensation signal for the discrete digital signal generated by the ARM is determined based on the relationship between the sum of the actual value and the differential value of the reversing step current and the magnitude of the negative analog voltage. ,in, The feedback time of the current source; The inverted step current signal output by the current source is + .

10. The control method for a DC inverting step current source based on real-time process control according to claim 9, characterized in that, Discrete digital signals are shown in the following equation: = ， ＜0 = ， ≥0 In the formula, It is a discrete digital signal. , These are the analog voltages corresponding to the initial and final values ​​of the target value of the reversing step current, respectively. This is a positive analog voltage. It is a negative analog voltage. =0 represents the step jump moment.

11. The control method for a DC inverting step current source based on real-time process control according to claim 10, characterized in that, The feedback voltage signal satisfies the following relationship: =0， ＜0 = ， ≥0。 12. The control method for a DC inverting step current source based on real-time process control according to claim 11, characterized in that, Actual value of reverse step current The single-point differential value is ,in, For the first Each sample value, For the first -1 sample value; feedback compensation signal As shown in the following formula: =A， +3 ＜ =0， +3 ≥ In the formula, Let A be the feedback time of the current source. × , This is the time needed for things to stabilize.

13. A terminal, comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 8-12.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 8-12.

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