Resistance-capacitance circuit constant current precision control method

Abstract

The invention discloses a resistance-capacitance circuit constant current precision control method, and relates to the technical field of resistance-capacitance circuits, and the method specifically comprises the steps: S1, constructing a resistance-capacitance circuit topology, and building a small signal model based on the resistance-capacitance circuit topology; s2, double-closed-loop control of an outer current loop and an inner voltage loop is adopted, a reference voltage signal is generated in the outer current loop through a PI controller, and current tracking is achieved in the inner voltage loop based on a nonlinear algorithm; and S3, introducing a dynamic compensation mechanism, and adaptively inhibiting a precision error through feed-forward compensation and parameters. According to the invention, double closed-loop control of outer loop current and inner loop voltage is adopted, and dynamic compensation is carried out on current errors through feed-forward compensation and parameter self-adaption. And the constant current precision control of the multi-branch resistance-capacitance circuit is realized by precisely calculating the duty ratio and performing closed-loop correction.

Description

Technical Field

[0001] The present invention relates to the technical field of resistor-capacitor circuits, and in particular to a constant current precision control method for resistor-capacitor circuits. Background Art

[0002] The RC circuit is a common circuit structure. In recent years, China's electronics industry has continued to develop steadily. Many devices that rely on RC circuits for power supply have also continuously increased their requirements for current, showing a trend of high stability and high precision. For example, in some lighting systems, precise constant current control can ensure stable luminous brightness and color consistency. In precision instruments such as sensors and measuring instruments, RC circuits can also be used as constant current sources to provide them with stable operating current. Realizing constant current precision control of RC circuits plays a key role in ensuring equipment performance, extending service life, and improving power efficiency. Therefore, the constant current precision control method of RC circuits is a promising research direction.

[0003] At present, the Chinese invention patent application with application number CN201310659937.5 discloses a control method for improving the constant current accuracy of the RC step-down circuit, which includes: detecting the actual output current value of the RC step-down circuit; determining whether the actual output current value of the RC step-down circuit is equal to the preset rated output current value of the RC step-down circuit; when the actual output current value of the RC step-down circuit is equal to the preset rated output current value of the RC step-down circuit, returning to continue to detect the actual output current value of the RC step-down circuit; when the actual output current value of the RC step-down circuit is not equal to the preset rated output current value of the RC step-down circuit, adjusting the actual output current value of the RC step-down circuit, and then returning to continue to detect the actual output current value of the RC step-down circuit. However, the application only establishes a current and voltage model based on a simple Ohm's law when analyzing the circuit, and its adaptability is limited. After setting the parameters, the ability to adjust the control parameters in real time according to the actual working conditions to adapt to different current and voltage requirements is insufficient. In addition, the dynamic characteristics analysis of the circuit under different working conditions is not considered, and the constant current performance changes of the circuit under load changes, power supply fluctuations, etc. are not adequately dealt with. When controlling the current, there is no closed-loop feedback control, and it is impossible to make real-time adjustments according to the actual current changes. There is a delay in the control analysis of the resistor-capacitor circuit, and there is a lack of predictive analysis of the current and flexible dynamic compensation. Summary of the invention

[0004] The technical problem solved by the present invention is: the traditional method adopts single-loop control when performing constant current precision control on the resistor-capacitor circuit, and does not form a closed-loop feedback control, which is not conducive to real-time adjustment according to the change of the actual current. After setting the parameters, the ability to adjust the control parameters in real time according to the actual working conditions to adapt to different current and voltage requirements is insufficient. In addition, the dynamic characteristics analysis of the circuit under different working conditions is not considered, and the constant current performance changes of the circuit under load changes, power supply fluctuations, etc. are not adequately dealt with. When controlling the current, it does not have a feedforward compensation function, and cannot compensate for known interference factors in advance. It can only be adjusted through feedback after the interference occurs, which will cause hysteresis in the adjustment and affect the constant current precision. There is a delay when controlling and analyzing the resistor-capacitor circuit, and there is a lack of predictive analysis of the current and flexible dynamic compensation.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: Step S1, constructing a resistor-capacitor circuit topology, and establishing a small signal model based on the resistor-capacitor circuit topology; Step S2, adopting a double closed-loop control of an outer current loop and an inner voltage loop, wherein a reference voltage signal is generated by a PI controller in the outer current loop, and current tracking is implemented based on a nonlinear algorithm in the inner voltage loop; Step S3, introduce a dynamic compensation mechanism to suppress precision errors through feedforward compensation and parameter adaptation.

[0006] As a preferred solution of the constant current precision control method of a resistor-capacitor circuit described in the present invention, wherein: the transfer function of the small signal model is calculated based on the resistor-capacitor circuit topology and the Laplace transform algorithm, and the small signal model is established based on the transfer function. The expression of the transfer function of the small signal model is: ; in, represents the transfer function of the small signal model, is the Laplace operator, is the Laplace transform of the output current, is the duty cycle disturbance, is the input voltage, is the load resistance, is the capacitance, is the inductor, is the capacitor's equivalent series resistance.

[0007] Among them, using small signal models to describe resistance and capacitance is beneficial to reflecting the frequency domain properties and dynamic characteristics of the circuit.

[0008] As a preferred solution of the constant current precision control method of a resistor-capacitor circuit described in the present invention, the outer current loop uses the output current signal as feedback quantity, and With reference current The current error signal is obtained by performing difference calculation, and the current error signal is proportionally integrated through the PI controller. The current error signal is responded to through the proportional term, and the steady-state error corresponding to the current error signal is eliminated through the integral term, and the inner loop reference voltage value is output. , the transfer function expression of the PI controller is: ; ; Where, e is the current error signal, is the output current signal, is the reference current, is the transfer function of the PI controller, is the proportionality coefficient, is the integral coefficient, and s is the Laplace operator.

[0009] Among them, the double closed-loop construction consisting of an outer current loop and an inner voltage loop takes into account the fact that although the RC circuit itself has a simple structure, it can be used as part of a complex circuit. The establishment of an outer current loop and an inner voltage loop control is conducive to the precise control and regulation of current and voltage. By first using the inner voltage loop to stabilize the voltage and then using the outer current loop to control the output current in a coordinated manner, it is conducive to stable tracking of the reference current, without being disturbed by factors such as load changes, and improving the accuracy of constant current control, thereby improving the adaptability of the method.

[0010] As a preferred solution of the constant current precision control method of a resistor-capacitor circuit described in the present invention, the inner loop voltage loop is based on the capacitor voltage is the feedback quantity, based on the capacitor voltage , the inner loop reference voltage value of the outer loop output The nonlinear current tracking algorithm is designed based on the Lyapunov stability theory. The current error signal is used as the error function. The real-time duty cycle is calculated and adjusted through the nonlinear current tracking algorithm. The expression of the real-time duty cycle is: ; Where t represents time, is the real-time duty cycle, is the reference current change rate, k is the convergence coefficient, is the capacitor voltage, e is the current error signal, is the output current signal, is the power supply voltage.

[0011] Among them, the PI controller has a simple structure and is easy to implement, but the error is large when it is directly used to control the current. After the inner loop reference voltage value is obtained by integral calculation of the PI controller, the nonlinear current tracking algorithm designed in combination with the Lyapunov stability theory is used to calculate the real-time duty cycle, which is conducive to improving the control accuracy and enhancing the applicability of complex circuits. Factors such as the reference current change rate, current error, and capacitor voltage are fully considered to improve the dynamic response performance of the system. It can quickly and accurately adjust the duty cycle according to the circuit state, and can respond quickly to load mutations, input voltage fluctuations, etc., to achieve stable current tracking and precision control.

[0012] As a preferred solution of the constant current precision control method of a resistor-capacitor circuit described in the present invention, wherein: for a multi-way parallel resistor-capacitor circuit structure, the branch current precision error is suppressed through feedforward compensation and parameter adaptation, and the precision error includes input voltage fluctuation, load change and temperature drift.

[0013] As a preferred solution of the constant current precision control method of a resistor-capacitor circuit described in the present invention, the real-time input voltage is monitored to establish the input voltage Duty cycle correction The duty cycle correction is calculated based on the linear mapping relationship. The duty cycle correction is added to the nominal duty cycle through feedforward compensation to complete the correction. The linear mapping relationship between the input voltage and the duty cycle correction is expressed as: ; in, is the input voltage change, is the nominal duty cycle.

[0014] Among them, in a multi-channel parallel resistor-capacitor circuit, input voltage fluctuations will affect the stability of all branch currents. This application monitors the real-time input voltage, establishes a linear mapping relationship between the input voltage and the duty cycle correction amount, calculates the duty cycle correction amount and superimposes it on the nominal duty cycle, which is conducive to timely adjusting the duty cycle of each branch according to the input voltage change, thereby compensating for the impact of input voltage fluctuations on branch currents. Feedforward compensation can effectively improve the anti-interference ability and stability of multi-channel parallel resistor-capacitor circuits, and enhances the constant current control accuracy from the perspective of predicting fluctuations and feedback.

[0015] As a preferred solution of the constant current precision control method of a resistor-capacitor circuit described in the present invention, wherein: the capacitor equivalent series resistance and temperature coefficient are controlled by an adaptive observer, and the parameter update formula of the adaptive observer is: ; ; in, is the initial proportional coefficient of the PI controller, is the initial convergence coefficient, is the equivalent series resistance compensation coefficient, is the temperature compensation coefficient, is the equivalent series resistance deviation, is the temperature change.

[0016] As a preferred solution of the constant current precision control method of a resistor-capacitor circuit described in the present invention, the adaptive observer calculates the real-time estimated value of the capacitor equivalent series resistance by recursive least squares method based on the capacitor voltage and output current at time k, and the parameter identification model of the adaptive observer is: ; Among them, t represents time, k represents the historical moment, is the real-time estimated value of the capacitor equivalent series resistance, argmin represents the independent variable value corresponding to the minimum value of the function, For the forgetting factor, is the capacitor voltage at time k, is the output current at time k.

[0017] Among them, the capacitor equivalent series resistance and temperature coefficient will change with environmental changes, affecting circuit performance. Based on the recursive least squares method, the adaptive observer uses the historical data of capacitor voltage and output current to calculate the real-time estimated value of the capacitor equivalent series resistance, and adjusts the proportional coefficient and convergence coefficient of the PI controller according to the capacitor equivalent series resistance deviation and temperature change, so that the controller can adapt to changes in circuit parameters. By using the adaptive observer to establish a parameter adaptive mechanism, the adaptability and robustness of the control current accuracy are improved.

[0018] As a preferred scheme of the constant current precision control method of a RC circuit described in the present invention, in which: in a RC circuit with a multi-way parallel structure, the main branch current is set as a reference, the duty cycle of the jth branch is calculated based on the main branch duty cycle, the main branch load resistance and the jth branch load resistance, and the current disturbance is offset by a closed-loop correction algorithm.

[0019] As a preferred solution of the constant current precision control method of a resistor-capacitor circuit described in the present invention, the duty cycle and closed-loop correction algorithm of the j-th branch are expressed as follows: ; ; in, is the duty cycle of the j-th branch, is the main branch duty cycle, is the main branch load resistance, is the load resistance of the j-th branch, represents the duty cycle of the jth branch at time t, represents the predicted duty cycle of the jth branch at time t+1, To adjust the gain for the shunt, is the output current of the jth branch.

[0020] Among them, the present application sets the main branch current as the benchmark, calculates the duty cycle of the jth branch according to the main branch duty cycle, the main branch load resistance and the jth branch load resistance, and adapts to different current distribution ratio scenarios through a closed-loop correction algorithm. The duty cycle of the jth branch is adjusted according to the difference in current between the main branch and the jth branch to offset current disturbances, which is conducive to ensuring the distribution accuracy of the current of each branch.

[0021] The beneficial effects of the present invention are as follows: by establishing a small signal model of a resistor-capacitor circuit based on the circuit topology for analysis, it is beneficial to the subsequent analysis of the circuit under different conditions, such as the change in constant current performance of the circuit when encountering load changes and power supply changes. The double closed-loop construction consisting of an outer current loop and an inner voltage loop takes into account the fact that although the resistor-capacitor circuit itself has a simple structure, it can be used as part of a complex circuit. The establishment of an outer current loop and an inner voltage loop control is beneficial to the precise control and regulation of current and voltage. By first using the inner voltage loop to stabilize the voltage and then using the outer current loop to control the output current in a coordinated manner, it is beneficial to improve the accuracy of constant current control. The use of a nonlinear algorithm to achieve current tracking is beneficial to adapting to the nonlinear characteristics in a complex resistor-capacitor circuit system. The introduction of a dynamic compensation mechanism can instantly adjust the control strategy and parameters based on real-time current and voltage feedback, which is beneficial to suppressing the constant current output error caused by factors such as temperature changes, component aging, and load mutations in the circuit. By adjusting the feedforward compensation of the duty cycle, it is beneficial to predict and compensate for interference factors, avoid the hysteresis of traditional feedback regulation methods, and improve constant current accuracy and system response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A basic flow chart of a method for controlling constant current precision of a resistor-capacitor circuit provided by an embodiment of the present invention; Figure 2 A schematic diagram of a resistor-capacitor circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, but not all of the embodiments.

[0024] Reference Figure 1, is an embodiment of the present invention, and provides a constant current precision control method for a resistor-capacitor circuit, comprising: Step S1, constructing a resistor-capacitor circuit topology, and establishing a small signal model based on the resistor-capacitor circuit topology; Step S2, adopting a double closed-loop control of an outer current loop and an inner voltage loop, wherein a reference voltage signal is generated by a PI controller in the outer current loop, and current tracking is implemented based on a nonlinear algorithm in the inner voltage loop; Step S3, introduce a dynamic compensation mechanism to suppress precision errors through feedforward compensation and parameter adaptation.

[0025] In this embodiment, the transfer function of the small signal model is calculated based on the RC circuit topology and the Laplace transform algorithm, and the small signal model is established based on the transfer function. The expression of the transfer function of the small signal model is: ; in, represents the transfer function of the small signal model, is the Laplace operator, is the Laplace transform of the output current, is the duty cycle disturbance, is the input voltage, is the load resistance, is the capacitance, is the inductor, is the capacitor's equivalent series resistance.

[0026] Among them, using small signal models to describe resistance and capacitance is beneficial to reflecting the frequency domain properties and dynamic characteristics of the circuit.

[0027] In this embodiment, the outer current loop uses the output current signal as feedback. With reference current The current error signal is obtained by performing difference calculation, and the current error signal is proportionally integrated through the PI controller. The current error signal is responded to through the proportional term, and the steady-state error corresponding to the current error signal is eliminated through the integral term, and the inner loop reference voltage value is output. , the transfer function expression of the PI controller is: ; ; Where, e is the current error signal, is the output current signal, is the reference current, is the transfer function of the PI controller, is the proportionality coefficient, is the integral coefficient, and s is the Laplace operator.

[0028] Among them, the double closed-loop construction consisting of an outer current loop and an inner voltage loop takes into account the fact that although the RC circuit itself has a simple structure, it can be used as part of a complex circuit. The establishment of an outer current loop and an inner voltage loop control is conducive to the precise control and regulation of current and voltage. By first using the inner voltage loop to stabilize the voltage and then using the outer current loop to control the output current in a coordinated manner, it is conducive to stable tracking of the reference current, without being disturbed by factors such as load changes, and improving the accuracy of constant current control, thereby improving the adaptability of the method.

[0029] In this embodiment, the inner voltage loop is based on the capacitor voltage is the feedback quantity, based on the capacitor voltage , the inner loop reference voltage value of the outer loop output The nonlinear current tracking algorithm is designed based on the Lyapunov stability theory. The current error signal is used as the error function. The real-time duty cycle is calculated and adjusted through the nonlinear current tracking algorithm. The expression of the real-time duty cycle is: ; Where t represents time, is the real-time duty cycle, is the reference current change rate, k is the convergence coefficient, is the capacitor voltage, e is the current error signal, is the output current signal, is the power supply voltage.

[0030] Among them, the PI controller has a simple structure and is easy to implement, but the error is large when it is directly used to control the current. After the inner loop reference voltage value is obtained by integral calculation of the PI controller, the nonlinear current tracking algorithm designed in combination with the Lyapunov stability theory is used to calculate the real-time duty cycle, which is conducive to improving the control accuracy and enhancing the applicability of complex circuits. Factors such as the reference current change rate, current error, and capacitor voltage are fully considered to improve the dynamic response performance of the system. It can quickly and accurately adjust the duty cycle according to the circuit state, and can respond quickly to load mutations, input voltage fluctuations, etc., to achieve stable current tracking and precision control.

[0031] In this embodiment, for a multi-channel parallel resistor-capacitor circuit structure, the branch current is subjected to precision error suppression through feedforward compensation and parameter adaptation, and the precision error includes input voltage fluctuation, load change and temperature drift.

[0032] In this embodiment, the real-time input voltage is monitored to establish the input voltage Duty cycle correction The duty cycle correction is calculated based on the linear mapping relationship. The duty cycle correction is added to the nominal duty cycle through feedforward compensation to complete the correction. The linear mapping relationship between the input voltage and the duty cycle correction is expressed as: ; in, is the input voltage change, is the nominal duty cycle.

[0033] Among them, in a multi-channel parallel resistor-capacitor circuit, input voltage fluctuations will affect the stability of all branch currents. This application monitors the real-time input voltage, establishes a linear mapping relationship between the input voltage and the duty cycle correction amount, calculates the duty cycle correction amount and superimposes it on the nominal duty cycle, which is conducive to timely adjusting the duty cycle of each branch according to the input voltage change, thereby compensating for the impact of input voltage fluctuations on branch currents. Feedforward compensation can effectively improve the anti-interference ability and stability of multi-channel parallel resistor-capacitor circuits, and enhances the constant current control accuracy from the perspective of predicting fluctuations and feedback.

[0034] In this embodiment, the adaptive observer is used to control the capacitor equivalent series resistance and the temperature coefficient as parameters, and the parameter update formula of the adaptive observer is: ; ; in, is the initial proportional coefficient of the PI controller, is the initial convergence coefficient, is the equivalent series resistance compensation coefficient, is the temperature compensation coefficient, is the equivalent series resistance deviation, is the temperature change.

[0035] In this embodiment, the adaptive observer calculates the real-time estimated value of the capacitor equivalent series resistance by recursive least squares method based on the capacitor voltage and output current at time k. The parameter identification model of the adaptive observer is: ; Among them, t represents time, k represents the historical moment, is the real-time estimated value of the capacitor equivalent series resistance, argmin represents the independent variable value corresponding to the minimum value of the function, For the forgetting factor, is the capacitor voltage at time k, is the output current at time k.

[0036] Among them, the capacitor equivalent series resistance and temperature coefficient will change with environmental changes, affecting circuit performance. Based on the recursive least squares method, the adaptive observer uses the historical data of capacitor voltage and output current to calculate the real-time estimated value of the capacitor equivalent series resistance, and adjusts the proportional coefficient and convergence coefficient of the PI controller according to the capacitor equivalent series resistance deviation and temperature change, so that the controller can adapt to changes in circuit parameters. By using the adaptive observer to establish a parameter adaptive mechanism, the adaptability and robustness of the control current accuracy are improved.

[0037] In this embodiment, in a multi-channel parallel resistor-capacitor circuit, the main branch current is set as a reference, the duty cycle of the jth branch is calculated based on the main branch duty cycle, the main branch load resistance and the jth branch load resistance, and the current disturbance is offset by a closed-loop correction algorithm.

[0038] In this embodiment, the duty cycle of the j-th branch and the closed-loop correction algorithm are expressed as: ; ; in, is the duty cycle of the j-th branch, is the main branch duty cycle, is the main branch load resistance, is the load resistance of the j-th branch, represents the duty cycle of the jth branch at time t, represents the predicted duty cycle of the jth branch at time t+1, To adjust the gain for the shunt, is the output current of the jth branch.

[0039] Among them, the present application sets the main branch current as the benchmark, calculates the duty cycle of the jth branch according to the main branch duty cycle, the main branch load resistance and the jth branch load resistance, and adapts to different current distribution ratio scenarios through a closed-loop correction algorithm. The duty cycle of the jth branch is adjusted according to the difference in current between the main branch and the jth branch to offset current disturbances, which is conducive to ensuring the distribution accuracy of the current of each branch.

[0040] It should be understood by those skilled in the art that embodiments of the present invention may provide methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program codes. Among them, the storage medium may be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, referred to as SRAM), erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, referred to as EPROM), programmable read-only memory (Programmable Red-Only Memory, referred to as PROM), read-only memory (Read-Only Memory, referred to as ROM), magnetic memory, flash memory, magnetic disk or optical disk. These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0041] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A constant current precision control method for a resistance-capacitance circuit, characterized in that: include: Step S1, constructing a resistor-capacitor circuit topology, and establishing a small signal model based on the resistor-capacitor circuit topology; Step S2, adopting a double closed-loop control of an outer current loop and an inner voltage loop, wherein a reference voltage signal is generated by a PI controller in the outer current loop, and current tracking is implemented based on a nonlinear algorithm in the inner voltage loop; Step S3, introduce a dynamic compensation mechanism to suppress precision errors through feedforward compensation and parameter adaptation.

2. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 1, characterized in that: The transfer function of the small signal model is calculated based on the RC circuit topology and the Laplace transform algorithm, and the small signal model is established based on the transfer function. The expression of the transfer function of the small signal model is: ； in, represents the transfer function of the small signal model, is the Laplace operator, is the Laplace transform of the output current, is the duty cycle disturbance, is the input voltage, is the load resistance, is the capacitance, is the inductor, is the capacitor's equivalent series resistance.

3. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 1, characterized in that: The outer current loop uses the output current signal as feedback. With reference current The current error signal is obtained by performing difference calculation, and the current error signal is proportionally integrated through the PI controller. The current error signal is responded to through the proportional term, and the steady-state error corresponding to the current error signal is eliminated through the integral term, and the inner loop reference voltage value is output. , the transfer function expression of the PI controller is: ； ； Where, e is the current error signal, is the output current signal, is the reference current, is the transfer function of the PI controller, is the proportionality coefficient, is the integral coefficient, and s is the Laplace operator.

4. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 3, characterized in that: The inner voltage loop is based on the capacitor voltage is the feedback quantity, based on the capacitor voltage , the inner loop reference voltage value of the outer loop output The nonlinear current tracking algorithm is designed based on the Lyapunov stability theory. The current error signal is used as the error function. The real-time duty cycle is calculated and adjusted through the nonlinear current tracking algorithm. The expression of the real-time duty cycle is: ； Where t represents time, is the real-time duty cycle, is the reference current change rate, k is the convergence coefficient, is the capacitor voltage, e is the current error signal, is the output current signal, is the power supply voltage.

5. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 1, characterized in that: For a multi-channel parallel resistor-capacitor circuit structure, the branch current is suppressed for accuracy error through feedforward compensation and parameter adaptation. The accuracy error includes input voltage fluctuation, load change and temperature drift.

6. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 5, characterized in that: Monitor the real-time input voltage and establish the input voltage Duty cycle correction The duty cycle correction is calculated based on the linear mapping relationship. The duty cycle correction is added to the nominal duty cycle through feedforward compensation to complete the correction. The linear mapping relationship between the input voltage and the duty cycle correction is expressed as: ； in, is the input voltage change, is the nominal duty cycle.

7. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 5, characterized in that: The adaptive observer is used to control the equivalent series resistance and temperature coefficient of the capacitor. The parameter update formula of the adaptive observer is: ； ； in, is the initial proportional coefficient of the PI controller, is the initial convergence coefficient, is the equivalent series resistance compensation coefficient, is the temperature compensation coefficient, is the equivalent series resistance deviation, is the temperature change.

8. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 7, characterized in that: The adaptive observer calculates the real-time estimated value of the capacitor equivalent series resistance by recursive least squares method based on the capacitor voltage and output current at time k. The parameter identification model of the adaptive observer is: ； Among them, t represents time, k represents the historical moment, is the real-time estimated value of the equivalent series resistance of the capacitor, argmin represents the value of the independent variable corresponding to the minimum value of the function, and argmin represents the value of the independent variable corresponding to the minimum value of the function. For the forgetting factor, is the capacitor voltage at time k, is the output current at time k.

9. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 1, characterized in that: In a multi-channel parallel resistor-capacitor circuit, the main branch current is set as a reference, and the duty cycle of the jth branch is calculated based on the main branch duty cycle, the main branch load resistance and the jth branch load resistance, and the current disturbance is offset by a closed-loop correction algorithm.

10. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 9, characterized in that: The duty cycle and closed-loop correction algorithm of the j-th branch are expressed as: ； ； in, is the duty cycle of the j-th branch, is the main branch duty cycle, is the main branch load resistance, is the load resistance of the j-th branch, represents the duty cycle of the jth branch at time t, represents the predicted duty cycle of the jth branch at time t+1, To adjust the gain for the shunt, is the output current of the jth branch.

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