Closed-loop current control method and system based on adaptive voltage regulation

Abstract

The invention provides a closed-loop current control method and system based on adaptive voltage regulation. The method comprises the following steps: calculating a current error according to an actually measured current and a target current; calculating a theoretical voltage adjustment amount according to the current error; applying an attenuation factor to the theoretical voltage adjustment amount to obtain an actual voltage adjustment amount; updating an output voltage based on the actual voltage adjustment amount; and repeatedly executing the steps until the current error meets a preset convergence condition, and outputting a final voltage. A current error is calculated and an attenuation factor is introduced to carry out dynamic constraint on a theoretical voltage adjustment amount so that a loop iteration adaptive adjustment mechanism is formed. The problems of output oscillation and hardware protection caused by overlarge voltage adjustment amount in a traditional control scheme are avoided, and the stability of the adjustment process is effectively improved while the convergence precision of the system is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic control, and in particular to a closed-loop current control method and system based on adaptive voltage regulation. Background Art

[0002] Constant current sources are essential devices in the field of power electronics. Their core function is to precisely regulate output current through closed-loop control. Currently, common constant current source systems utilize a closed-loop feedback loop consisting of a signal source, power amplifier, current sampling, and controller modules. This system achieves constant current output by sampling output current in real time and dynamically adjusting the output voltage. Specifically, the signal source module receives adjustment commands via a serial port protocol and outputs a reference voltage signal. The power amplifier module converts this signal into a low-voltage, high-current output. The current sampling module monitors the output current in real time, and the controller calculates and issues voltage adjustment commands based on the sampling results, thus forming a complete feedback control chain. However, in practical applications, the voltage-current relationship exhibits nonlinear characteristics due to the dynamic changes in load impedance. Traditional closed-loop control algorithms are prone to persistent oscillations and slow convergence during the regulation process. For example, when the initial voltage is 0.1V, the output current fluctuates repeatedly around the target value of 5A (e.g., 5.2A → 4.8A → 5.15A → 4.9A), requiring approximately 10 seconds to reach a stable state. In addition, the voltage adjustment amount lacks reasonable constraints, which can easily cause the power amplifier power chip to trigger the overcurrent or overvoltage protection mechanism due to instantaneous power mutations, resulting in abnormal output interruption, seriously affecting the reliability and efficiency of the system. Summary of the Invention

[0003] The purpose of the present invention is to solve the problem of repeated oscillation and slow convergence of output current in dynamic load scenarios.

[0004] A first aspect of the present invention provides a closed-loop current control method based on adaptive voltage regulation, comprising:

[0005] Calculate the current error based on the measured current and the target current;

[0006] Calculating a theoretical voltage adjustment amount based on the current error;

[0007] Applying an attenuation factor to the theoretical voltage adjustment to obtain an actual voltage adjustment;

[0008] updating the output voltage based on the actual voltage adjustment amount;

[0009] The above steps are repeated until the current error meets a preset convergence condition and a final voltage is output.

[0010] Furthermore, calculating the theoretical voltage adjustment amount further includes:

[0011] Calculate real-time load impedance based on current output voltage and measured current;

[0012] Dynamically modifying the voltage-current model and the reference PID parameters according to the real-time load impedance;

[0013] The corrected PID parameters are used in combination with the current error to calculate the theoretical voltage adjustment.

[0014] Furthermore, the real-time load impedance

[0015]

[0016] Where V' is the current output voltage and I' is the measured output current.

[0017] Furthermore, the current error

[0018] ΔI=II'

[0019] Where I is the target current value.

[0020] Furthermore, the preset convergence condition is: |ΔI|≤0.5%I and the continuous stabilization time exceeds a preset time.

[0021] Furthermore, the theoretical voltage adjustment amount

[0022]

[0023] Kd is the differential coefficient.

[0024] Furthermore, the actual voltage adjustment amount

[0025]

[0026] Where ΔVmax is the maximum voltage step size and α is the attenuation factor.

[0027] Furthermore, the range of α is 0.5-0.8.

[0028] Furthermore, the output voltage V=V'+ΔV'.

[0029] A second aspect of the present invention provides a closed-loop current control system based on adaptive voltage regulation, comprising:

[0030] Signal source module, providing and adjusting voltage output signal;

[0031] Power amplifier module, converting voltage signals into low-voltage, high-current signals;

[0032] Sampling module, which samples the output current and output voltage in real time;

[0033] The adaptive control module executes the closed-loop current control method as described in any one of the above items.

[0034] Compared to existing technologies, the present invention offers at least the following advantages: By calculating the current error and introducing an attenuation factor to dynamically constrain the theoretical voltage adjustment, an iterative adaptive regulation mechanism is formed. This avoids the output oscillation and hardware protection issues associated with excessive voltage adjustment in traditional control schemes, effectively improving the smoothness of the regulation process while ensuring convergence accuracy. Furthermore, the output current convergence time is shortened, and the instantaneous power of the power amplifier remains within a safe range throughout the regulation process, significantly enhancing the system's control performance and operational reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings such as the provided drawings can be obtained without creative work.

[0036] Figure 1 1 is a flow chart of a closed-loop current control method according to an embodiment of the present invention;

[0037] Figure 2 Schematic diagram of a module of a closed-loop current control system in one embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be described in more detail below with reference to schematic diagrams, which illustrate preferred embodiments of the present invention. It should be understood that those skilled in the art may modify the present invention as described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as being generally known to those skilled in the art and not as limiting the present invention.

[0039] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0040] The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent as described below. It should be noted that the drawings are greatly simplified and not to exact scale, and are provided solely for the purpose of assisting in the description of the embodiments of the present invention.

[0041] Example 1

[0042] Provides a closed-loop current control method based on adaptive voltage regulation, please refer to Figure 1 ,include:

[0043] Calculate the current error based on the measured current and the target current;

[0044] Calculating a theoretical voltage adjustment amount based on the current error;

[0045] Applying an attenuation factor to the theoretical voltage adjustment to obtain an actual voltage adjustment;

[0046] updating the output voltage based on the actual voltage adjustment amount;

[0047] The above steps are repeated until the current error meets a preset convergence condition and a final voltage is output.

[0048] Specifically, by comparing the actual output current value with the target current value set by the user, the current deviation is calculated, providing a basis for subsequent voltage adjustments. The voltage change theoretically required to achieve the target current is calculated based on the current error. The theoretically calculated voltage adjustment is then scaled by introducing an attenuation factor to avoid system oscillations and amplifier protection issues caused by excessive single adjustments. Finally, the attenuated voltage adjustment is added to the current output voltage. The entire control process is an iterative optimization process, continuously performing current detection, error calculation, and voltage adjustment until the error between the output current and the target value is less than a preset threshold, completing the adjustment.

[0049] Furthermore, calculating the theoretical voltage adjustment amount further includes:

[0050] Calculate real-time load impedance based on current output voltage and measured current;

[0051] Dynamically modifying the voltage-current model and the reference PID parameters according to the real-time load impedance;

[0052] The corrected PID parameters are used in combination with the current error to calculate the theoretical voltage adjustment.

[0053] Specifically, the present application improves the accuracy of the calculation of the theoretical voltage adjustment by introducing the calculation of real-time load impedance and dynamically correcting the voltage-current model and the benchmark PID parameters. First, the real-time load impedance is calculated based on the current output voltage and the measured current. This step can accurately reflect the real-time state of the load. Secondly, the voltage-current model and the benchmark PID parameters are dynamically corrected according to the real-time load impedance to ensure that the model and parameters can adapt to the dynamic changes of the load. Finally, the corrected PID parameters are used in combination with the current error to calculate the theoretical voltage adjustment, making the adjustment more accurate and effectively solving the problem of model inaccuracy caused by dynamic changes in load impedance. The stability and response speed of the closed-loop current control system are significantly improved, and the problems of continuous oscillation and slow convergence caused by dynamic changes in load impedance are avoided, thereby improving the reliability and utilization efficiency of the system.

[0054] Furthermore, the real-time load impedance

[0055]

[0056] Where V' is the current output voltage and I' is the measured output current.

[0057] To calculate real-time load impedance, a voltage sensor collects the current output voltage, and a current sensor collects the measured output current. These two are then combined to calculate the real-time load impedance. Real-time measurement of output voltage and current accurately reflects changes in load impedance, providing a precise basis for subsequent voltage adjustments. This allows the system to better adapt to dynamic load changes and avoid control instability or slow convergence caused by load impedance fluctuations.

[0058] Furthermore, the current error

[0059] ΔI=II'

[0060] Where I is the target current value.

[0061] Specifically, the target current value I is the preset desired current value, while the measured output current I' is the actual output current value collected in real time by the current sampling module. Subtracting the target current value from the measured output current value yields the current error, which reflects the deviation between the actual output current and the target current.

[0062] By defining the current error calculation formula, accurate current error calculation is ensured. This technical feature plays a key role in closed-loop current control, and its accuracy directly impacts the subsequent calculation of voltage adjustment and output voltage updates. By accurately calculating the current error, the system can more precisely adjust the output voltage, thereby achieving the preset convergence conditions more quickly and achieving constant current output. This effectively reduces error accumulation in the current error calculation, improves the stability and response speed of closed-loop control, and thus resolves the persistent oscillation and slow convergence that are common in traditional closed-loop control algorithms during the regulation process.

[0063] Furthermore, the preset convergence condition is: |ΔI|≤0.5%I and the continuous stabilization time exceeds a preset time.

[0064] Specifically, the preset time can be set according to the actual application scenario. For example, in an industrial control system, the preset time can be set to 10 seconds to ensure that the current error can remain stable for more than 10 seconds while meeting the condition of less than 0.5% I. In addition, the preset time can also be adjusted according to the dynamic response characteristics of the system. For example, in a fast-response system, the preset time can be shortened to 100 milliseconds, while in a system requiring higher stability, the preset time can be extended to 20 seconds. As a preferred embodiment, the preset time can be optimized through experiments or simulations to ensure that the system can achieve the expected stability effect under different load conditions.

[0065] To address this, a preset time is set as a condition for the sustained stabilization time to ensure that the current error remains stable after meeting the preset convergence conditions, thus preventing the current error from fluctuating again within a short period of time. By adding constraints in the time dimension, the stability and reliability of current control are further improved, ensuring that the system can maintain stable output for a long time after reaching the target current, avoiding system instability or abnormal interruptions caused by fluctuations after a brief period of stability.

[0066] Furthermore, the theoretical voltage adjustment amount

[0067]

[0068] Kp, Ki and Kd are all PID parameters, where Kp is the proportional coefficient, Ki is the integral coefficient, and Kd is the differential coefficient.

[0069] The PID control algorithm adjusts voltage in response to current errors using the proportional coefficient Kp, the integral coefficient Ki, and the differential coefficient Kd. The proportional coefficient Kp is used to quickly respond to errors, the integral coefficient Ki eliminates steady-state errors, and the differential coefficient Kd predicts error trends, allowing for proactive voltage adjustments. This combination of PID parameters effectively calculates the theoretical voltage adjustment, enabling precise current control.

[0070] Specifically, the value of the proportional coefficient Kp can be adjusted based on the system's response speed and stability requirements. Generally, a larger Kp value accelerates the system's response speed but may cause system instability; a smaller Kp value improves system stability but slows down the response speed. The value of the integral coefficient Ki can be adjusted based on the system's steady-state error requirements. A larger Ki value eliminates the steady-state error more quickly but may cause the system to overshoot; a smaller Ki value reduces overshoot but eliminates the steady-state error more slowly. The value of the differential coefficient Kd can be adjusted based on the system's prediction of the error trend. A larger Kd value predicts the error trend more quickly but may cause the system to be sensitive to noise; a smaller Kd value reduces noise sensitivity but slows down the prediction of the error trend.

[0071] As a preferred embodiment, the values of the PID parameters can be optimized through experiments or simulations to ensure that the system achieves an optimal balance between response speed, stability, and steady-state error. For example, by gradually adjusting the values of Kp, Ki, and Kd and observing the system response curve, a parameter combination that results in a fast and stable system response can be selected.

[0072] Furthermore, the actual voltage adjustment amount

[0073]

[0074] Where ΔVmax is the maximum voltage step size and α is the attenuation factor.

[0075] Furthermore, the range of α is 0.5-0.8.

[0076] Specifically, the attenuation factor α is used to dynamically adjust the theoretical voltage adjustment amount, making it smoother and more controllable in practical applications, while the maximum voltage step size ΔVmax further constrains the upper limit of the voltage adjustment amount, ensuring that the system will not experience instantaneous power mutations during the adjustment process.

[0077] As a preferred embodiment, the attenuation factor α ranges from 0.5 to 0.8. For example, when α is 0.6, the theoretical voltage adjustment will be attenuated to 60% of the original value, effectively reducing the voltage adjustment amplitude. In addition, the maximum voltage step size ΔVmax can be set according to the specific needs of the system, for example, to 0.5V to ensure that the amplitude of each voltage adjustment does not exceed this value.

[0078] Therefore, by introducing the attenuation factor α and the maximum voltage step size ΔVmax, the actual voltage adjustment range is limited, thus avoiding system instability or triggering of protection mechanisms caused by excessive voltage adjustment. This can effectively reduce oscillations during the voltage adjustment process, improve system stability and reliability, and avoid triggering protection mechanisms due to instantaneous power surges, ensuring normal system operation.

[0079] Furthermore, the output voltage V=V'+ΔV'.

[0080] Example 2

[0081] The second aspect of the present invention provides a closed-loop current control system based on adaptive voltage regulation, please refer to Figure 2 ,include:

[0082] Signal source module, providing and adjusting voltage output signal;

[0083] Power amplifier module, converting voltage signals into low-voltage, high-current signals;

[0084] Sampling module, which samples the output current and output voltage in real time;

[0085] The adaptive control module executes the closed-loop current control method as described in any one of the above items.

[0086] Specifically, the signal source module can be implemented by a digital signal processor (DSP) or a microcontroller, and can dynamically adjust the output voltage according to external instructions or internal algorithms. The power amplifier module can use devices such as power MOSFET or IGBT to ensure that the voltage signal can be efficiently converted into a large current output. The sampling module can be implemented by a Hall sensor or a shunt resistor, which can accurately measure the output current and feed it back to the adaptive control module. In this embodiment, the frequency of the sampling module can be set as needed. The adaptive control module can be implemented by an FPGA or a dedicated control chip, which can dynamically adjust the output voltage according to real-time current data to ensure that the system converges quickly and operates stably.

[0087] As a preferred embodiment, the voltage sensor and current sensor can be high-precision, low-noise sensors to improve measurement accuracy. In addition, the microprocessor can be a processor with high-speed computing capabilities to ensure that the real-time load impedance calculation can be completed quickly to meet the real-time requirements of the system.

[0088] The following explains it with a specific example:

[0089] After the system is powered on, the adaptive control module automatically performs a hardware self-test (including testing the signal source, power amplifier module, and communication link of the metering chip). The target current value, I = 5A, is set through the human-machine interface (such as a touch screen or host computer), and a start command is triggered. The control module loads the initial parameters: attenuation factor α = 0.5, maximum voltage step size ΔVmax = 0.2V.

[0090] Next, the adaptive control module sends an initial output voltage command of 0.1 V to the signal source module. The sampling module is started synchronously to collect the output current value in real time, with a sampling rate set to 1 kHz, and obtains the measured current I' in real time through the SPI interface.

[0091] The adaptive control module then calculates the load impedance and current error in real time based on the current output voltage V' and the measured current I'. It then calculates the theoretical voltage adjustment ΔV using the PID control algorithm. A dynamic attenuation factor α is applied, and the maximum step size is limited to generate a new output voltage command. This newly generated voltage command is sent to the signal source module in the form of a hexadecimal floating-point number (e.g., 0x3DCCCCCD represents 0.1V). During operation, the power amplifier module status is monitored in real time (via GPIO interrupts). If overcurrent is detected, the output is immediately suspended and the fault recovery process is executed.

[0092] After outputting a new voltage command, the current error value is re-detected, and the steps are periodically executed at a control frequency of 200 Hz until the current error value meets the convergence conditions: |ΔI| ≤ 0.5% I (i.e., |5A-I| ≤ 0.025A) and the continuous stabilization time is ≥ 100ms.

[0093] Through the above steps, compared with the traditional method that requires more than 20 iterations, a convergence time of >10s, and ≥8 oscillations, this application reduces the number of iterations to ≤5 and the convergence time to ≤2s by using the attenuation factor and step size limit. This also shortens the convergence time of the output current, and the instantaneous power of the power amplifier power supply is always kept within a safe range during the entire regulation process.

[0094] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art can make several simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. A closed-loop current control method based on adaptive voltage regulation, characterized in that: include: Calculate the current error based on the measured current and the target current; Calculating a theoretical voltage adjustment amount based on the current error; Applying an attenuation factor to the theoretical voltage adjustment to obtain an actual voltage adjustment; updating the output voltage based on the actual voltage adjustment amount; The above steps are repeated until the current error meets a preset convergence condition and a final voltage is output.

2. The closed-loop current control method according to claim 1, wherein: Calculating the theoretical voltage adjustment amount further includes: Calculate real-time load impedance based on current output voltage and measured current; Dynamically modifying the voltage-current model and the reference PID parameters according to the real-time load impedance; The corrected PID parameters are used in combination with the current error to calculate the theoretical voltage adjustment.

3. The closed-loop current control method according to claim 2, wherein: The real-time load impedance Where V' is the current output voltage and I' is the measured output current.

4. The closed-loop current control method according to claim 3, wherein: The current error ΔI=II′ Where I is the target current value.

5. The closed-loop current control method according to claim 4, wherein: The preset convergence condition is: |ΔI|≤0.5%I and the continuous stabilization time exceeds the preset time.

6. The closed-loop current control method according to claim 4, wherein: The theoretical voltage adjustment Kp, Ki and Kd are all PID parameters, where Kp is the proportional coefficient, Ki is the integral coefficient, and Kd is the differential coefficient.

7. The closed-loop current control method according to claim 6, wherein: The actual voltage adjustment amount Where ΔVmax is the maximum voltage step size and α is the attenuation factor.

8. The closed-loop current control method according to claim 7, wherein: The range of α is 0.5-0.

8.

9. The closed-loop current control method according to claim 7, wherein: The output voltage V=V′+ΔV′.

10. A closed-loop current control system based on adaptive voltage regulation, characterized in that: include: Signal source module, providing and adjusting voltage output signal; Power amplifier module, converting voltage signals into low-voltage, high-current signals; Sampling module, which samples the output current and output voltage in real time; An adaptive control module executes the closed-loop current control method according to any one of claims 1 to 9.

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