A method for controlling the constant current accuracy of a resistor-capacitor circuit

Abstract

The present invention discloses a method for controlling the constant current accuracy of a resistor-capacitor circuit, which relates to the technical field of resistor-capacitor circuits. Specifically, it includes: 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. In the outer current loop, a reference voltage signal is generated by a PI controller, and in the inner voltage loop, current tracking is achieved based on a non-linear algorithm; Step S3, introducing a dynamic compensation mechanism to suppress accuracy errors through feed-forward compensation and parameter adaptation. This application adopts a double closed-loop control of an outer current and an inner voltage, and dynamically compensates the current error through feed-forward compensation and parameter adaptation. Through accurate calculation of the duty cycle and closed-loop correction, the constant current accuracy control of a multi-branch resistor-capacitor circuit is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of resistor-capacitor circuits, and particularly to a method for controlling the constant current accuracy of a resistor-capacitor circuit. Background Art

[0002] A resistor-capacitor circuit is a common circuit structure. In recent years, China's electronic industry has developed continuously and steadily, and the requirements for current by many devices relying on resistor-capacitor circuits for power supply have been increasing, 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, a resistor-capacitor circuit can also be used as a constant current source to provide a stable working current. Achieving constant current accuracy control for a resistor-capacitor circuit plays a key role in ensuring device performance, extending service life, and improving power utilization efficiency. Therefore, the method for controlling the constant current accuracy of a resistor-capacitor circuit is a promising research direction.

[0003] Currently, the Chinese patent application with the application number CN201310659937.5 discloses a control method for improving the constant current accuracy of a resistor-capacitor buck circuit. The application includes: detecting the actual output current value of the resistor-capacitor buck circuit; determining whether the actual output current value of the resistor-capacitor buck circuit is equal to the preset rated output current value of the resistor-capacitor buck circuit; when the actual output current value of the resistor-capacitor buck circuit is equal to the preset rated output current value of the resistor-capacitor buck circuit, returning to continue detecting the actual output current value of the resistor-capacitor buck circuit; when the actual output current value of the resistor-capacitor buck circuit is not equal to the preset rated output current value of the resistor-capacitor buck circuit, adjusting the actual output current value of the resistor-capacitor buck circuit, and then returning to continue detecting the actual output current value of the resistor-capacitor buck circuit. However, when analyzing the circuit, this application only establishes a current-voltage model based on the simple Ohm's law, with limited adaptability. After setting the parameters, it lacks the ability to adjust the control parameters in real time according to the actual working conditions to meet different current-voltage requirements. In addition, it does not consider the dynamic characteristic analysis of the circuit under different working conditions, and is insufficient in dealing with the changes in the constant current performance of the circuit under load changes, power fluctuations, etc. When controlling the current, there is no closed-loop feedback control, and it is impossible to make real-time adjustments according to the changes in the actual current. There is a delay in the control analysis of the resistor-capacitor circuit, lacking predictive analysis of the current and flexible dynamic compensation. Summary of the Invention

[0004] The technical problem solved by the present invention is that when the traditional method controls the constant current accuracy of the resistor-capacitor circuit, it uses single-loop control 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, there is insufficient ability to adjust the control parameters in real time according to the actual working conditions to meet different current and voltage requirements. In addition, the dynamic characteristics analysis of the circuit under different working conditions is not considered, and the response to the change of the constant current performance of the circuit under conditions such as load change and power supply fluctuation is insufficient. When controlling the current, it does not have a feed-forward compensation function, and cannot compensate for known interference factors in advance. It can only be adjusted through feedback after the interference occurs, which will lead to a lag in adjustment and affect the constant current accuracy. 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.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] Step S1, construct a resistor-capacitor circuit topology and establish a small-signal model based on the resistor-capacitor circuit topology;

[0007] Step S2, adopt a double closed-loop control of an outer current loop and an inner voltage loop. In the outer current loop, a reference voltage signal is generated through a PI controller, and in the inner voltage loop, current tracking is achieved based on a non-linear algorithm;

[0008] Step S3, introduce a dynamic compensation mechanism to suppress the accuracy error through feed-forward compensation and parameter self-adaptation.

[0009] As a preferred solution of a method for controlling the constant current accuracy of a resistor-capacitor circuit according to 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:

[0010] ;

[0011] Wherein, 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 perturbation, is the input voltage, is the load resistance, is the capacitor, is the inductor, is the equivalent series resistance of the capacitor.

[0012] Wherein, using the small-signal model to describe the resistor-capacitor is beneficial to reflecting the frequency-domain properties and dynamic characteristics of the circuit.

[0013] As a preferred solution of a constant current precision control method for a resistor-capacitor circuit according to the present invention, wherein: the outer current loop uses the output current signal as the feedback quantity, and for the output current signal and the reference current a difference calculation is performed to obtain a current error signal, and the PI controller performs proportional integral operation on the current error signal. The proportional term responds to the current error signal, and the integral term eliminates the steady-state error corresponding to the current error signal, and outputs the inner loop reference voltage value . The transfer function expression of the PI controller is:

[0014] ;

[0015] ;

[0016] wherein, 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 proportional coefficient of the PI controller, is the integral coefficient, and s is the Laplace operator.

[0017] Among them, a double closed-loop structure composed of an outer current loop and an inner voltage loop is adopted, considering the situation that although the resistor-capacitor circuit has a simple structure by itself, it can be used as a part of a complex circuit. Establishing the control of the outer current loop and the inner voltage loop is beneficial to the precise control and regulation of the current and voltage. By coordinating in the order of first stabilizing the voltage with the inner voltage loop and then controlling the output current with the outer current loop, it is beneficial to stably track the reference current, not affected by factors such as load changes, and improve the accuracy of the constant current control, thereby improving the adaptability of the method.

[0018] As a preferred solution of a constant current precision control method for a resistor-capacitor circuit according to the present invention, wherein: the inner voltage loop uses the capacitor voltage as the feedback quantity, and based on the capacitor voltage , the inner loop reference voltage value output by the outer loop and the Lyapunov stability theory, a nonlinear current tracking algorithm is designed. Taking the current error signal 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:

[0019] ;

[0020] wherein, t represents time, is the real-time duty cycle, is the reference current change rate, k is the convergence coefficient, is the capacitor voltage, and e is the current error signal. is the output current signal, is the power supply voltage.

[0021] Among them, the PI controller has a simple structure and is easy to implement, but the direct use for controlling the current has a large error. After obtaining the inner-loop reference voltage value according to the integral calculation of the PI controller, a non-linear current tracking algorithm designed in combination with the Lyapunov stability theory is used to calculate the real-time duty cycle, which is beneficial to improving the control accuracy and enhancing the applicability to complex circuits. It fully considers factors such as the reference current change rate, current error, and capacitor voltage, and improves the dynamic response performance of the system. It can quickly and accurately adjust the duty cycle according to the circuit state, and can quickly respond when facing situations such as sudden load changes and input voltage fluctuations, realizing stable tracking and precision control of the current.

[0022] As a preferred scheme of a constant current precision control method for a resistor-capacitor circuit according to the present invention, wherein: for a multi-branch parallel resistor-capacitor circuit structure, the precision error of the branch current is suppressed through feedforward compensation and parameter adaptation, and the precision error includes input voltage fluctuation, load change, and temperature drift.

[0023] As a preferred scheme of a constant current precision control method for a resistor-capacitor circuit according to the present invention, wherein: the real-time input voltage is monitored to establish the input voltage and the duty cycle correction amount of the linear mapping relationship, based on the linear mapping relationship, the duty cycle correction amount is calculated, and the duty cycle correction amount is superimposed on the nominal duty cycle through feedforward compensation to complete the correction. The linear mapping relationship expression of the input voltage and the duty cycle correction amount is:

[0024] ;

[0025] Among them, is the input voltage change amount, is the nominal duty cycle.

[0026] Among them, in a multi-branch parallel resistor-capacitor circuit, the input voltage fluctuation 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 beneficial to timely adjusting the duty cycle of each branch according to the input voltage change, thereby compensating for the influence of the input voltage fluctuation on the branch current. Feedforward compensation can effectively improve the anti-interference ability and stability of the multi-branch parallel resistor-capacitor circuit, and enhance the constant current control precision from the perspective of predicting fluctuations and feedback.

[0027] As a preferred scheme of a constant current precision control method for a resistor-capacitor circuit according to the present invention, wherein: the equivalent series resistance and temperature coefficient of the capacitor are controlled by an adaptive observer, and the parameter update formula of the adaptive observer is:

[0028] ;

[0029] ;

[0030] Among them, 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, is the proportional coefficient of the PI controller at time t, is the convergence coefficient at time t.

[0031] As a preferred scheme of a constant current precision control method for a resistor-capacitor circuit according to the present invention, wherein: the adaptive observer calculates the real-time estimated value of the capacitance equivalent series resistance based on the capacitance voltage and the output current at time q through the recursive least squares method, and the parameter identification model of the adaptive observer is:

[0032] ;

[0033] Among them, t represents time, q represents the historical time, is the real-time estimated value of the capacitance equivalent series resistance, argmin represents the independent variable value corresponding to the minimum value of the function, is the forgetting factor, is the capacitance voltage at time q, is the output current at time q.

[0034] Among them, the capacitance equivalent series resistance and the temperature coefficient will change with the environment, affecting the circuit performance. The adaptive observer calculates the real-time estimated value of the capacitance equivalent series resistance based on the historical data of the capacitance voltage and the output current through the recursive least squares method, and adjusts the proportional coefficient and the convergence coefficient of the PI controller according to the capacitance equivalent series resistance deviation and the temperature change, so that the controller can adapt to the change of the circuit parameters. By using the adaptive observer to establish a parameter adaptive mechanism, the self-adaptability and robustness of the control current precision are improved.

[0035] As a preferred scheme of a constant current precision control method for a resistor-capacitor circuit according to the present invention, wherein: in a resistor-capacitor circuit with a multi-path parallel structure, the main branch current is set as a reference, and the duty ratio of the j-th branch is calculated based on the duty ratio of the main branch, the load resistance of the main branch, and the load resistance of the j-th branch, and the current disturbance is canceled through a closed-loop correction algorithm.

[0036] As a preferred solution of the constant current precision control method for the resistor-capacitor circuit described in the present invention, wherein: the expressions of the duty cycle of the j-th branch and the closed-loop correction algorithm are:

[0037] ;

[0038] ;

[0039] Wherein, is the duty cycle of the j-th branch, is the duty cycle of the main branch, is the load resistance of the main branch, is the load resistance of the j-th branch, represents the duty cycle of the j-th branch at time t, represents the predicted duty cycle of the j-th branch at time t + 1, is the shunt regulation gain, is the output current of the j-th branch.

[0040] Among them, in this application, the main branch current is set as the reference, the duty cycle of the j-th branch is calculated according to the duty cycle of the main branch, the load resistance of the main branch and the load resistance of the j-th branch, and the closed-loop correction algorithm is used to adapt to different current distribution ratio scenarios. The duty cycle of the j-th branch is adjusted according to the current difference between the main branch and the j-th branch to offset the current disturbance, which is beneficial to ensuring the distribution accuracy of the currents of each branch.

[0041] Advantages of the present invention: By establishing a small-signal model of the resistor-capacitor circuit based on the circuit topology for analysis, it is beneficial for subsequent analysis of the circuit under different conditions, such as the constant current performance changes of the circuit when encountering load changes and power supply changes. The double closed-loop structure composed of an outer current loop and an inner voltage loop is adopted, considering the situation that although the resistor-capacitor circuit has a simple structure itself, it can be used as a part of a complex circuit. Establishing the control of the outer current loop and the inner voltage loop is beneficial for precisely controlling and regulating the current and voltage. By coordinating in the order of first stabilizing the voltage with the inner voltage loop and then controlling the output current with the outer current loop, it is beneficial to improve the accuracy of constant current control. Using a non-linear algorithm to achieve current tracking is beneficial for adapting to the non-linear characteristics in a complex resistor-capacitor circuit system. Introducing a dynamic compensation mechanism can instantaneously adjust the control strategy and parameters according to the real-time current and voltage feedback, which is beneficial for suppressing the constant current output error caused by factors such as temperature changes, component aging, and load mutations in the circuit. By adjusting the feed-forward compensation of the duty cycle, it is beneficial for predicting and compensating interference factors, avoiding the lag of traditional feedback regulation methods, and improving the constant current accuracy and system response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic diagram of the basic flow of a constant current precision control method for a resistor-capacitor circuit provided by an embodiment of the present invention;

[0043] Figure 2 Schematic diagram of a resistor-capacitor circuit provided by an embodiment of the present invention. Specific embodiments

[0044] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given in conjunction with the accompanying drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments.

[0045] Refer to Figure 1 , an embodiment of the present invention provides a method for controlling the constant current accuracy of a resistor-capacitor circuit, including:

[0046] Step S1, construct a resistor-capacitor circuit topology, and establish a small-signal model based on the resistor-capacitor circuit topology;

[0047] Step S2, adopt a double closed-loop control of an outer current loop and an inner voltage loop. In the outer current loop, a reference voltage signal is generated by a PI controller, and in the inner voltage loop, current tracking is achieved based on a nonlinear algorithm;

[0048] Step S3, introduce a dynamic compensation mechanism to suppress accuracy errors through feedforward compensation and parameter adaptation.

[0049] In this embodiment, 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:

[0050] ;

[0051] Wherein, 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 perturbation, is the input voltage, is the load resistance, is the capacitor, is the inductor, is the equivalent series resistance of the capacitor.

[0052] Among them, using the small-signal model to describe the resistor-capacitor is beneficial to reflecting the frequency-domain properties and dynamic characteristics of the circuit.

[0053] In this embodiment, the outer current loop uses the output current signal as the feedback quantity for the output current signal and the reference current The difference operation is performed to obtain the current error signal. The PI controller performs proportional-integral operation on the current error signal. The proportional term responds to the current error signal, and the integral term eliminates the steady-state error corresponding to the current error signal, and outputs the inner-loop reference voltage value , and the transfer function expression of the PI controller is:

[0054] ;

[0055] ;

[0056] 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 proportional coefficient of the PI controller, is the integral coefficient, and s is the Laplace operator.

[0057] Among them, a double closed-loop structure composed of an outer-loop current loop and an inner-loop voltage loop is adopted, considering the situation that although the resistor-capacitor circuit has a simple structure itself, it can be used as a part of a complex circuit. Establishing the outer-loop current loop and the inner-loop voltage loop control is beneficial to the precise control and adjustment of the current and voltage. By coordinating in the order of first stabilizing the voltage with the inner-loop voltage loop and then controlling the output current with the outer-loop current loop, it is beneficial to stably track the reference current, without being interfered by factors such as load changes, and improve the accuracy of constant current control, thereby improving the adaptability of the method.

[0058] In this embodiment, the inner-loop voltage loop uses the capacitor voltage as the feedback quantity, and designs a nonlinear current tracking algorithm based on the capacitor voltage , the inner-loop reference voltage value output by the outer loop and the Lyapunov stability theory. Taking the current error signal 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:

[0059] ;

[0060] 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.

[0061] Among them, the PI controller has a simple structure and is easy to implement, but the direct use for controlling current has a large error. After obtaining the inner-loop reference voltage value through the integral calculation of the PI controller, a non-linear current tracking algorithm designed in combination with the Lyapunov stability theory is used to calculate the real-time duty cycle, which is beneficial to improving the control accuracy and enhancing the applicability to 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 quickly respond when facing situations such as sudden load changes and input voltage fluctuations, realizing stable tracking and precision control of the current.

[0062] In this embodiment, for the multi-path parallel resistor-capacitor circuit structure, the precision error of the branch current is suppressed through feed-forward compensation and parameter adaptation, and the precision error includes input voltage fluctuation, load change, and temperature drift.

[0063] In this embodiment, the real-time input voltage is monitored to establish the input voltage and the duty cycle correction amount of the linear mapping relationship. Based on the linear mapping relationship, the duty cycle correction amount is calculated, and the duty cycle correction amount is superimposed on the nominal duty cycle through feed-forward compensation to complete the correction. The linear mapping relationship expression of the input voltage and the duty cycle correction amount is:

[0064] ;

[0065] Among them, is the input voltage change amount, is the nominal duty cycle.

[0066] Among them, in the multi-path parallel resistor-capacitor circuit, the input voltage fluctuation will affect the stability of all branch currents. This application monitors the real-time input voltage, establishes the 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 beneficial to timely adjusting the duty cycle of each branch according to the input voltage change, so as to compensate for the influence of the input voltage fluctuation on the branch current. Feed-forward compensation can effectively improve the anti-interference ability and stability of the multi-path parallel resistor-capacitor circuit, and enhance the constant current control accuracy from the perspective of predicting fluctuations and feedback.

[0067] In this embodiment, an adaptive observer is used to control the parameters of the equivalent series resistance and temperature coefficient of the capacitor. The parameter update formula of the adaptive observer is:

[0068] ;

[0069] ;

[0070] Among them, 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, is the proportional coefficient of the PI controller at time t, is the convergence coefficient at time t.

[0071] In this embodiment, the adaptive observer calculates the real-time estimated value of the capacitor equivalent series resistance based on the capacitor voltage and output current at time q through the recursive least squares method. The parameter identification model of the adaptive observer is:

[0072] ;

[0073] where t represents time and q represents the historical time, is the real-time estimated value of the capacitor equivalent series resistance, and argmin represents the independent variable value corresponding to the minimum value of the function, is the forgetting factor, is the capacitor voltage at time q, is the output current at time q.

[0074] Among them, the capacitor equivalent series resistance and the temperature coefficient will change with the environment, affecting the circuit performance. The adaptive observer is based on the recursive least squares method, uses the historical data of the 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 equivalent series resistance deviation and temperature change, so that the controller can adapt to the change of circuit parameters. By using the adaptive observer to establish a parameter adaptive mechanism, the self-adaptability and robustness of the control current accuracy are improved.

[0075] In this embodiment, in the capacitive-resistive circuit with a multi-path parallel structure, the main branch current is set as the reference, and the duty cycle of the j-th branch is calculated based on the duty cycle of the main branch, the load resistance of the main branch, and the load resistance of the j-th branch. The current disturbance is cancelled through the closed-loop correction algorithm.

[0076] In this embodiment, the expressions of the duty cycle of the j-th branch and the closed-loop correction algorithm are:

[0077] ;

[0078] ;

[0079] where is the duty cycle of the j-th branch, is the duty cycle of the main branch, is the load resistance of the main branch, is the load resistance of the j-th branch, represents the duty cycle of the j-th branch at time t, represents the predicted duty cycle of the j-th branch at time t+1, is the shunt regulation gain, is the output current of the j-th branch.

[0080] Among them, in this application, the main branch current is set as the reference. The duty cycle of the j-th branch is calculated based on the duty cycle of the main branch, the load resistance of the main branch, and the load resistance of the j-th branch, and the closed-loop correction algorithm is used to adapt to different current distribution ratio scenarios. The duty cycle of the j-th branch is adjusted according to the current difference between the main branch and the j-th branch to offset the current disturbance, which is beneficial to ensuring the distribution accuracy of the currents of each branch.

[0081] Those skilled in the art should understand that the embodiments of the present invention can provide a method, a system, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code. Among them, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (abbreviated as SRAM), electrically erasable programmable read-only memory (abbreviated as EEPROM), erasable programmable read-only memory (abbreviated as EPROM), programmable read-only memory (abbreviated as PROM), read-only memory (abbreviated as ROM), magnetic memory, flash memory, magnetic disk, or optical disk. These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device, and the instruction device implements the functions specified in one process Figure 1 one process or multiple processes and / or boxes Figure 1 specified in one box or multiple boxes.

[0082] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within 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 achieved based on a nonlinear algorithm in the inner voltage loop; Step S3, introducing a dynamic compensation mechanism to suppress precision errors through feedforward compensation and parameter adaptation; Among them, 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, is the load resistance, L is the inductance; 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, is the proportional coefficient of the PI controller at time t, is the convergence coefficient at time t; 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 q. The parameter identification model of the adaptive observer is: ； Among them, t represents time, q represents 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 q, is the output current at time q.

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 proportional coefficient of the PI controller, 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 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.

5. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 4, 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.

6. 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.

7. A constant current precision control method for a resistance-capacitance circuit as claimed in claim 6, 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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