PWM signal voltage stabilization method, system and circuit based on LM358 module

Abstract

The invention provides a PWM signal voltage stabilization method, system and circuit based on an LM358 module, and the method comprises the steps: dynamically adjusting the conduction or cut-off state of an MOSFET tube Q1 according to the size of an output voltage through the MOSFET tube Q1, adjusting the closed-loop gain of a negative feedback circuit to the output voltage, and achieving the voltage stabilization control. The method comprises the following steps: monitoring an output voltage Vo in real time, comparing the output voltage Vo with half of a highest threshold Vo, max, and dynamically adjusting the state of Q1 to change a negative feedback coefficient; a calculation model for calculating feedback voltage coefficients of the negative feedback circuit and the positive feedback circuit and related gains Hp (s) and Hn (s); and a closed-loop gain H (s) is calculated by combining the duty ratio of the PWM regulation and control signal of the EP32 main control module, and the optimal PWM duty ratio and the output voltage regulation value are solved based on the gain. The high-precision voltage stabilizing circuit has the beneficial effects of high response speed and high voltage stabilizing precision, and can be widely applied to high-precision voltage stabilizing scenes in the field of industrial control.

Description

Technical Field

[0001] The invention belongs to the technical field of stabilizing output voltage by using PWM pulse width modulation, and specifically relates to a PWM signal stabilization method, system and circuit based on an LM358 module. Background Art

[0002] With the rapid development of electronic technology, the requirements for stability, reliability and power efficiency of various electronic devices and systems are increasing day by day. In addition, with the gradual miniaturization and high performance of various electronic devices, voltage stability and efficiency control have become increasingly important. Pulse Width Modulation (PWM), as a common voltage control technology, has been widely used in various power management systems. PWM technology controls the output voltage and power of the power supply by adjusting the pulse width of the output signal, and has become one of the core technologies in the design of efficient power supplies. However, the existing PWM voltage stabilization method still faces certain technical challenges in practical applications, including slow response speed, high noise, low regulation accuracy, and insensitive response to load changes.

[0003] For example, in the prior art, the Chinese utility model patent with publication number CN205610483U discloses a voltage-equalizing and voltage-stabilizing wide-voltage power supply, and the Chinese utility model patent with publication number CN201550022U discloses a power supply voltage stabilizing device. In the technologies disclosed in the two, the feedback loop is usually adjusted by a traditional analog circuit or digital circuit adjustment method to adjust the output voltage. This design is often difficult to cope with high dynamic load changes or rapid load change requirements, and the circuit complexity is high, the cost is high, and it is easily affected by external interference, especially in noise-sensitive application scenarios, which may lead to poor voltage stability and low efficiency. Another example is the Chinese invention patent with publication number CN109995252A, which discloses a voltage stabilizing circuit and a switching power supply circuit. The switching frequency and circuit topology structure in the PWM voltage stabilizing system it has lead to large switching losses, and even generate more obvious electromagnetic interference, and lack an effective feedback mechanism. The voltage adjustment process may have a large delay or over-adjustment, resulting in a long system response time.

[0004] In practical applications, although these traditional technologies can meet the voltage regulation requirements in certain scenarios, they still have many shortcomings. For example, when the load changes rapidly, the voltage regulator responds slowly, which may cause voltage fluctuations; the noise suppression capability is limited, especially during high-frequency switching operations, which may generate large electromagnetic interference; the regulation accuracy is limited, especially when the current changes greatly, it is impossible to accurately track the load requirements. In addition, due to the more complex filtering and feedback mechanisms in traditional circuits, the system design is often too complicated, the cost is high, and debugging and maintenance are difficult. Summary of the invention

[0005] In view of the above-mentioned defects, the present invention provides a PWM signal voltage stabilization method, system and circuit based on the LM358 module.

[0006] The present invention provides the following technical solution: a PWM signal voltage stabilization method based on an LM358 module, wherein the method uses a MOSFET tube Q1 to adjust whether it is turned on according to the magnitude of the output voltage, dynamically adjusts the closed-loop gain of the negative feedback circuit to the output voltage, and then cooperates with the negative feedback circuit to stabilize the output voltage, comprising the following steps:

[0007] S1: Real-time monitoring of the output voltage V of the PWM signal voltage regulator circuit with LM358 module o size;

[0008] S2: According to the output voltage V of the LM358 module o The magnitude of the output voltage maximum threshold V o,max The half of the comparison result is used to dynamically adjust the conduction or cutoff of the MOSFET tube Q1 as the source-drain switch, and then dynamically adjust the negative feedback coefficient to complete the adjustment of the contribution of the negative feedback voltage to the output voltage;

[0009] S3: Calculate the negative feedback voltage V output by the negative feedback circuit according to whether the MOSFET tube Q1 is turned on. n The negative feedback coefficient β n , and further calculate the positive feedback voltage V output by the positive feedback circuit p The positive feedback coefficient β p ;

[0010] S4: Output the PWM control signal to the voltage stabilizing circuit according to the comparison between the PWM control signal output by the EP32 main control module and the reference signal, and determine the PWM high level duration T according to the duty cycle of the PWM control signal. on And low level duration T off , further construct the positive feedback voltage gain function H p (s) and the negative feedback voltage gain function H n (s) calculation model, thereby obtaining the closed-loop gain H(s) of the voltage stabilizing circuit;

[0011] S5: Calculate the output voltage value V of the voltage stabilizing circuit according to the closed-loop gain H(s) of the voltage stabilizing circuit o,adj , solve the optimal duty cycle of the PWM control signal, and calculate the PWM signal to adjust the output voltage termination threshold Thr V ;

[0012] S6: Determine Thr VIs it less than 0.21? If so, the output voltage is adjusted to have the optimal duty cycle. Otherwise, repeat S1-S5 to stabilize the output voltage at (0, V o,max ] threshold range, V o,max is the maximum output voltage threshold.

[0013] Further, in the step S2, when When the oscillation signal in the voltage stabilizing circuit is too small, the MOSFET tube Q1 is controlled to be turned on, and then the sixth resistor R6 and the third capacitor C3 are grounded. At this time, the first diode D1 and the second diode D2 are not turned on, and only the third resistor R3, the fourth resistor R4 and the fifth resistor R5 form a negative feedback circuit and output a negative feedback voltage V n The output voltage V o Make dynamic adjustments;

[0014] when When the oscillation signal in the voltage stabilizing circuit is too large, the MOSFET tube Q1 is controlled to be cut off, and then the sixth resistor R6 and the third capacitor C3 participate in the feedback circuit. At this time, the first diode D1 and the second diode D2 are turned on, dynamically adjusting the influence of the negative feedback circuit on the output voltage.

[0015] Furthermore, when the MOSFET tube Q1 is turned on, the negative feedback voltage V output by the negative feedback circuit is calculated in step S3. n The negative feedback coefficient β n as follows:

[0016] Among them, R3, R4 and R5 are the resistance values ​​of the third resistor R3, the fourth resistor R4 and the fifth resistor R5 respectively.

[0017] When the MOSFET tube Q1 is turned off, the negative feedback coefficient β of the negative feedback voltage n as follows:

[0018] Among them, Z n is the impedance formed by the sixth resistor R6 and the third capacitor R3, R6 is the resistance value of the sixth resistor R6, C3 is the capacitance value of the third capacitor C3; j is an imaginary number, ω is the angular frequency of the PWM control signal, ω=2πf, f is the sinusoidal wave frequency of the PWM control signal, f=D / T on , D is the duty cycle of the PWM control signal.

[0019] Furthermore, in step S3, the positive feedback voltage V output by the positive feedback circuit is calculated. p The positive feedback coefficient β p The formula is as follows:

[0020] R1 and R2 are resistance values ​​of the first resistor R1 and the second resistor R2 respectively, and C1 and C2 are capacitance values ​​of the first capacitor C1 and the second capacitor C2 respectively.

[0021] Furthermore, the positive feedback voltage gain function H constructed in step S4 is p (s) and negative feedback voltage gain function H n (s) The calculation models are as follows:

[0022] Among them, φ o K is the initial phase angle of the output voltage of pin 1 of the LM358 module; p (s) is the gain coefficient of the positive feedback voltage on the duty cycle of the PWM control signal, K n (s) is the gain coefficient of negative feedback voltage to PWM signal duty cycle adjustment;

[0023]

[0024] Wherein, s is the unit variable analyzed in the complex frequency domain of the voltage stabilizing circuit, s=1 / (jw);

[0025] The closed-loop gain H(s) of the voltage stabilizing circuit is as follows:

[0026]

[0027] Furthermore, the step S5 includes:

[0028] S51: The closed-loop gain transfer function H(s) is converted from the complex frequency domain to the time domain by an inverse Laplace transform to obtain a closed-loop gain time domain function h(t):

[0029] Where γ is the real part of all singular points greater than H(s), j is an imaginary number, and j 2 = -1; T is the upper limit of integration. When T tends to infinity, the integration path covers the entire complex frequency domain, t∈[0,T]; nT D =T, n = 0, 1, 2, ....; T D =T on +T off , T D is a PWM control signal cycle, T on Account for T D The ratio is the duty cycle D of the PWM control signal, that is, D = T on / T D =T on / T on +T off;

[0030] S52: Based on the closed-loop gain time domain function h(t), solve the monitoring time range T m The output voltage V is regulated by the PWM signal. o,adj :

[0031] Among them, t0 is the start time of monitoring time, V cc is the DC input voltage applied to the steady-state circuit;

[0032] S53: Construct the optimal duty cycle model for solving the PWM control signal:

[0033] V o,ex is the ideal output voltage;

[0034] S54: According to the optimal duty cycle Dbest obtained by the step S53, it is brought into the steps S4 and S5 to calculate the closed-loop gain H with the optimal duty cycle best (s), and further obtain the regulated output voltage with the optimal duty cycle

[0035] S55: Calculate the PWM signal to adjust the output voltage termination threshold Thr V :

[0036]

[0037] Furthermore, the input voltage V applied to the steady-state circuit cc 12V~30V, input current I cc >100mA.

[0038] The present invention also provides a PWM signal voltage stabilization system based on the LM358 module for executing the above method, wherein the system comprises an EP32 main control module and a PWM signal to voltage conversion module comprising the LM358 module;

[0039] The EP32 main control module is used for PWM control of the output voltage of the PWM signal-to-voltage module; the PWM signal-to-voltage module includes a first green terminal row, a second green terminal row, a third green terminal row and a PWM signal jumper cap; the PWM signal jumper cap includes a first PWM peak jumper wiring area and a second PWM peak jumper wiring area;

[0040] The EP32 main control module is connected to the positive and negative electrodes of the second green terminal block (22) of the PWM signal-to-voltage module.

[0041] The present invention also provides a PWM signal voltage stabilizing circuit based on the LM358 module applied to the system as described above, wherein the circuit is arranged on the PWM signal voltage conversion module, and the circuit includes a first capacitor C1, a first resistor R1, a second capacitor C2, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third capacitor C3, a first diode D1, a second diode D2, and a MOSFET tube Q1 as a source-drain switch;

[0042] Pin 1 of the LM358 module is led out through the first line, and is connected in series with the second resistor R2 and the second capacitor C2 in sequence through the first line branch one, and is connected in series with the fourth resistor R4 through the first line branch two; the other end of the second capacitor C2 is connected to pin 3 of the LM358 module through the second line branch one, and is respectively connected to the first resistor R1 and the first capacitor C1 through the second line branch two, and the first resistor R1 and the first capacitor C1 are connected in parallel and then grounded; pin 2 of the LM358 module is led out through the third line, and is connected to the third resistor R3 through the third line branch one 131, and is led out again through the third line branch two, and is respectively connected to the other end of the fourth resistor R4 and the fifth resistor R5; the other end of the third resistor R3 is connected in parallel with the first resistor R1 and the first capacitor C1 and is grounded together, and the fourth resistor R4 and the One end of the first line branch 2 is connected to a tap to lead out a fourth line, which is respectively connected to the anode of the first diode D1 and the cathode of the second diode D2. The anode of the second diode D2 is connected to the sixth resistor R6 and then connected to one end of the third capacitor C3 and grounded. The other end of the sixth resistor R6 is connected to the anode of the first diode D1 and then connected to the other end of the third capacitor C3, and connected to the gate of the MOSFET tube Q1. The drain of the MOSFET tube Q1 is connected to the other end of the third resistor R5, and the source of the MOSFET tube Q1 is grounded together with the ground end of the third capacitor C3. Pin 1 of the LM358 module is connected to the positive electrode of the first green terminal of the PWM signal-to-voltage module through the first line, and outputs the adjusted output voltage with the optimal duty cycle obtained in the S6 step of the above method. The negative electrode of the first green terminal is grounded;

[0043] Pin 8 of the LM358 module is connected to the 12V-30V external power supply VCC pin through the positive pole of the third green terminal row, and pin 4 of the LM358 module is connected to the 12V-30V external power supply VEE pin through the negative pole of the third green terminal row; Pin 5 of the LM358 module is used to connect to the GIPO2 pin of the EP32 main control module through the positive pole of the second green terminal row of the PWM signal to voltage module, and is used to receive the PWM control signal; Pin 6 of the LM358 module is used to connect to the GND pin of the EP32 main control module through the negative pole of the second green terminal row and then be grounded together to realize the input of the reference voltage for comparison required for PWM control; Pin 7 of the LM358 module is then connected to Pin 6 of the LM358 module through an external resistor to form a feedback network for the PWM control signal, and optimize the duty cycle of the PWM control signal output;

[0044] Among them, the first resistor R1, the second resistor R2, the first capacitor C1 and the second capacitor C2 form a positive feedback circuit; when the MOSFET tube Q1 is turned on, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 form a negative feedback circuit; when the MOSFET tube Q1 is turned off, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the third capacitor C3, the first diode D1 and the second diode D2 form a negative feedback circuit.

[0045] Furthermore, the capacitance values ​​of the first capacitor C1 and the second capacitor are both 10nF, the capacitance value of the third capacitor is 2μF, the resistance values ​​of the first resistor R1, the second resistor R2 and the fifth resistor R5 are all 47kΩ, the resistance value of the third resistor R3 is 10kΩ, the resistance value of the fourth resistor R4 is 19kΩ, the resistance value of the sixth resistor R6 is 1MΩ, and the source-drain switch MOSFET tube Q1 is an N-channel MOSFET tube.

[0046] The beneficial effects of the present invention are:

[0047] 1. The PWM signal voltage stabilization method, system and circuit based on the LM358 module provided by the present invention have higher stability, lower cost, better anti-interference ability and higher system efficiency compared with the prior art. By utilizing the operational amplifier characteristics of the LM358 module and combining the precise adjustment of the PWM signal, it can not only improve the dynamic response capability of the power management system, but also reduce the complexity in the circuit, providing a more reliable voltage stabilization solution for high-performance electronic systems.

[0048] 2. The system and circuit provided by the present invention, due to the introduction of the LM358 module, enables the circuit design to more flexibly realize the rapid feedback and adjustment of the PWM signal. On this basis, combined with appropriate filtering technology, the high-frequency noise in the PWM signal can be significantly reduced, the system response speed can be further optimized, the voltage regulation process can be faster and more accurate, and the overall performance of the power management system can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0050] Figure 1 A schematic flow chart of a PWM signal voltage stabilization method based on an LM358 module provided by the present invention;

[0051] Figure 2 It is a schematic diagram showing the changes of the positive feedback voltage, the negative feedback voltage and the output voltage when the MOSFET tube Q1 is turned on in the real-time example of the present invention;

[0052] Figure 3 The output voltage V after the voltage stabilization circuit is regulated by the PWM control signal when the duty cycle is 15% and 25% respectively by the method of the present invention o,adj and output current I o,adj Schematic diagram of the changes;

[0053] Figure 4 The output voltage V after the voltage stabilization circuit is regulated by the PWM control signal when the duty ratio is 35% and 40% respectively. o,adj and output current I o,adj Schematic diagram of the changes;

[0054] Figure 5 The comparison diagram of output voltage error changes under four different duty cycles using the method of the present invention and the CNN method;

[0055] Figure 6 The comparison diagram of output voltage error changes under four different duty cycles using the method of the present invention and the GA method;

[0056] Figure 7 A schematic diagram of the structure of a PWM signal voltage stabilization system based on the LM358 module provided by the present invention;

[0057] Figure 8 This is a three-dimensional structural diagram of the PWM signal to voltage module in the system provided by the present invention;

[0058] Fig. 9 A schematic diagram of the three-dimensional structure of the PWM signal-to-voltage module in the system provided by the present invention from another perspective;

[0059] Fig.10 A circuit diagram of a PWM signal voltage stabilizing circuit based on an LM358 module provided by the present invention;

[0060] Fig.11 The internal structure and pin diagram of the LM358 module included in the system and circuit provided by the present invention. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] The present invention provides a PWM signal voltage stabilization method based on the LM358 module. The method uses a MOSFET tube Q1 to adjust whether it is turned on according to the size of the output voltage, dynamically adjusts the closed-loop gain of the negative feedback circuit to the output voltage, and then cooperates with the negative feedback circuit to stabilize the output voltage. Figure 1 As shown, the following steps are included:

[0063] S1: Real-time monitoring of the output voltage V of the PWM signal voltage regulator circuit with LM358 module o size;

[0064] S2: Output voltage V according to pin 1 of LM358 module o The magnitude of the output voltage maximum threshold V o,max The half of the comparison result is used to dynamically adjust the conduction or cutoff of the MOSFET tube Q1 as the source-drain switch, and then dynamically adjust the negative feedback coefficient to complete the adjustment of the contribution of the negative feedback voltage to the output voltage;

[0065] S3: Calculate the negative feedback voltage V output by the negative feedback circuit according to whether the MOSFET tube Q1 is turned on or not n The negative feedback coefficient β n , and further calculate the positive feedback voltage V output by the positive feedback circuit p The positive feedback coefficient β p ;

[0066] S4: According to the comparison between the PWM control signal output by the EP32 main control module and the reference signal, the PWM control signal is output to the voltage stabilization circuit, and the PWM high level duration T is determined according to the duty cycle of the PWM control signal. on And low level duration T off , further construct the positive feedback voltage gain function H p (s) and the negative feedback voltage gain function Hn (s) calculation model, and then obtain the closed-loop gain H(s) of the voltage stabilization circuit;

[0067] S5: Calculate the output voltage value V of the voltage regulator circuit according to the closed-loop gain H(s) of the voltage regulator circuit o,adj , solve the optimal duty cycle of the PWM control signal, and calculate the PWM signal regulation output voltage termination threshold THr V ;

[0068] S6: Determine THr V Is it less than 0.21? If so, the output voltage is adjusted to have the optimal duty cycle. Otherwise, repeat S1-S5 to stabilize the output voltage at (0, V o,max ] threshold range, V o,max is the maximum output voltage threshold.

[0069] This method can adjust the on and off states of the MOSFET tube in real time, realize closed-loop control, and ensure that the system automatically adjusts the output voltage according to the load changes. Compared with the traditional voltage stabilization method, this dynamic adjustment greatly improves the efficiency of the voltage stabilization system. By accurately adjusting the gain coefficients of negative feedback and positive feedback, the output voltage fluctuation can be effectively reduced and the stability of the system can be improved. Even when the external environment or load changes, this technology can still maintain a stable voltage output, thereby improving the reliability of the equipment. In addition, it can compare the output voltage with half of the highest threshold to determine whether the MOSFET tube Q1 needs to be turned on, and then provide different negative feedback circuit structures to change the positive or negative synergistic effect of the negative feedback voltage on the positive feedback voltage. By accurately calculating the feedback coefficient, the role of negative feedback and positive feedback in the voltage stabilization process can be more accurately controlled. Negative feedback is used to reduce gain and stabilize the output voltage; while positive feedback enhances the system response speed. The collaborative work of the two enables the power supply voltage stabilization system to achieve higher voltage accuracy and better dynamic response capability. Voltage stabilization can be achieved by adjusting the duty cycle of the PWM control signal, reducing dependence on complex circuits and reducing hardware costs. In addition, the existing LM358 modules and MOSFET tubes are used, which is easy to integrate into the existing system and has good compatibility and scalability.

[0070] As another preferred embodiment of the present invention, in step S2,

[0071] when When the oscillation signal in the voltage stabilizing circuit is too small, the MOSFET tube Q1 is controlled to be turned on, and then the sixth resistor R6 and the third capacitor C3 are grounded. At this time, the first diode D1 and the second diode D2 are not turned on, and only the third resistor R3, the fourth resistor R4 and the fifth resistor R5 form a negative feedback circuit and output a negative feedback voltage V n The output voltage Vo Dynamic adjustment is performed; after the fifth resistor R5 is connected in parallel with the third resistor R3, it is connected in series with R4 to form a negative feedback circuit, one end of R4 is connected to the output voltage end of the LM358 module, and the other end is connected to the parallel convergence end of the third resistor R3 and the fifth resistor R5, and the other end of the parallel convergence of the third resistor R3 and the fifth resistor R5 is connected to pin 2 of the LM358 module (the input end of the negative feedback voltage for output voltage gain adjustment);

[0072] when When the oscillation signal in the voltage stabilization circuit is too large, the MOSFET tube Q1 is controlled to be cut off, and then the sixth resistor R6 and the third capacitor C3 participate in the feedback circuit. At this time, the first diode D1 and the second diode D2 are turned on, which play the role of limiting and nonlinear regulation in the negative feedback circuit, and dynamically adjust the impact of the negative feedback circuit on the output voltage. The impedance Z formed by the third resistor R3, the fifth resistor R5, the sixth resistor R6 and the third capacitor R3 n After being connected in parallel, one end is connected in series with the fourth resistor R4, and the other end is grounded; one end of the parallel connection connected in series with the fourth resistor R4 is connected to pin 2 of the LM358 module (the input end for adjusting the output voltage gain of the negative feedback voltage), and the other end of the fourth resistor R4 is connected to the output voltage end of the LM358 module, thereby forming a negative feedback circuit when the MOSFET tube Q1 is turned off.

[0073] The output voltage maximum threshold V o,max is 10V, so if Figure 2 (a) shows the positive feedback voltage V in the PWM signal voltage stabilization circuit based on the LM358 module provided by the present invention. p Changing within the range of 0V-5V, such as Figure 2 As shown in (b), in the voltage stabilizing circuit provided by the present invention, when the MOSFET tube Q1 is turned on, as shown in Figure 2 The amplitude of the yellow fluctuation line in (b) is the negative feedback voltage V n The amplitude varies between 0V and 7.5V. Figure 2 The fluctuation amplitude of the orange dotted line in (b) is the negative feedback voltage V when the MOSFET tube Q1 is turned off. n The fluctuation amplitude varies between 0V and 3.3V; and then through the positive feedback voltage V n and negative feedback voltage V p The closed-loop gain H(s) of the entire voltage stabilization circuit is coupled and coordinated, and finally, Figure 2 As shown by the red wave line in (c), when the MOSFET tube Q1 is turned on, the final output voltage fluctuates between 0V and 10V. When the MOSFET tube Q1 is not turned on, Figure 2 The amplitude of the green dashed sine wave in (c) is the output voltage at this time, which varies in the range of 1.25V-8.75V.

[0074] As another preferred embodiment of the present invention, when the MOSFET tube Q1 is turned on, the negative feedback voltage V output by the negative feedback circuit is calculated in step S3. n The negative feedback coefficient β n as follows:

[0075] Among them, R3, R4 and R5 are the resistance values ​​of the third resistor R3, the fourth resistor R4 and the fifth resistor R5 respectively.

[0076] When the MOSFET tube Q1 is turned off, the negative feedback coefficient β of the negative feedback voltage n as follows:

[0077] Among them, Z n is the impedance formed by the sixth resistor R6 and the third capacitor R3, R6 is the resistance value of the sixth resistor R6, C3 is the capacitance value of the third capacitor C3; j is an imaginary number, ω is the angular frequency of the PWM control signal, ω=2πf, f is the sinusoidal wave frequency of the PWM control signal, f=D / T on , D is the duty cycle of the PWM control signal.

[0078] The role of MOSFET tube Q1 in the feedback circuit is not only the function of the physical switch, but also the key to optimizing the circuit performance by dynamically adjusting the feedback coefficient. Under the control of the PWM control signal input to the voltage stabilization circuit by the EP32 main control module, it can effectively adjust the output of the feedback circuit, thereby achieving precise control of the circuit performance, which is conducive to optimizing signal processing and enhancing system stability. The control of MOSFET tube Q1 makes the feedback characteristics controllable, and adjusts the feedback coefficient according to actual needs, so as to achieve precise control of the circuit output voltage amplitude. In different states, the energy transmission path is optimized by switching the feedback path, so that the circuit works in an efficient state. For example, when MOSFET Q1 is turned on, the circuit is simplified to reduce power consumption.

[0079] The switching characteristics of the MOSFET tube Q1 can adapt to the complex frequency components of the PWM signal. By adjusting the optimal duty cycle of the PWM control signal under different states of the MOSFET tube Q1 being on or off, it can adapt to the closed-loop gain contribution of the negative feedback voltage to the output voltage in the feedback path of different application scenarios, thereby filtering out high-frequency interference or optimizing low-frequency signals, and flexibly adapting to complex signals, thereby improving signal processing capabilities. At the same time, it can realize feedback adjustment in more states by changing the control signal of the MOSFET, thereby adapting to more application scenarios, and the output voltage of each application scenario is consistent with the ideal output voltage V o,ex The error is minimal.

[0080] In order to clarify the positive feedback voltage V output by the positive feedback circuit p And the negative feedback voltage V output by the negative feedback circuit n In order to determine the impact on the final output voltage of the voltage regulator circuit pin 1, it is necessary to clarify the feedback coefficient of each feedback voltage on the closed-loop gain, and then optimize the high-precision tracking and closed-loop gain control of the output voltage by the positive and negative feedback under the control of the PWM control signal. Therefore, as another preferred embodiment of the present invention, the positive feedback voltage V output by the positive feedback circuit is calculated in step S3. p The positive feedback coefficient β p The formula is as follows:

[0081] R1 and R2 are resistance values ​​of the first resistor R1 and the second resistor R2 respectively, and C1 and C2 are capacitance values ​​of the first capacitor C1 and the second capacitor C2 respectively.

[0082] The positive feedback voltage gain function H constructed in step S4 p (s) and the negative feedback voltage gain function H n (s) The calculation models are as follows:

[0083] Among them, φ o K is the initial phase angle of the output voltage of pin 1 of the LM358 module; p (s) is the gain coefficient of the positive feedback voltage on the duty cycle of the PWM control signal, K n (s) is the gain coefficient of negative feedback voltage to PWM signal duty cycle adjustment;

[0084]

[0085] Wherein, s is the unit variable analyzed in the complex frequency domain of the voltage stabilizing circuit, which is used to describe the dynamic changes of the voltage stabilizing circuit, including its frequency response, time response, and the changes in the closed-loop gain of the positive feedback circuit and the negative feedback circuit on the final output voltage; s = 1 / (jw);

[0086] The closed-loop gain H(s) of the voltage regulator circuit is as follows:

[0087]

[0088] The method provided by the present invention extends the feedback gain analysis to the complex frequency domain by introducing the s-domain signal, so that the voltage stabilization circuit can adapt to the dynamically changing PWM control signal. Under complex conditions such as frequency response and time response, the circuit behavior can also be accurately predicted and optimized. Positive feedback coefficient β p , negative feedback coefficient β n The calculation is ultimately reflected in the regulated output voltage V o,adjThe closed-loop gain H(s) of the PWM signal can be used to evaluate the stability of the feedback circuit, avoid potential oscillation or distortion problems, and improve the reliability of the circuit. The present invention organically combines the dynamic characteristics (duty cycle, phase angle, frequency response) of the PWM signal with the gain characteristics of the feedback circuit, and adjusts the gain coefficient K of the PWM signal duty cycle through the positive feedback voltage. p (s), negative feedback voltage to PWM signal duty cycle adjustment gain coefficient K n The calculation of (s) provides a mathematical model that is easy to optimize and supports rapid adjustment and analysis under different working conditions. At the same time, the introduction of ω (angular frequency) and s (complex frequency domain variable) in the formula enables the technical solution to be directly applicable to the voltage stabilization scenario of high-frequency PWM signals, and also enables the method provided by the present invention to support high-frequency application scenarios, thereby expanding the application scope of the voltage stabilization circuit.

[0089] As another preferred embodiment of the present invention, step S5 includes:

[0090] S51: The closed-loop gain transfer function H(s) is converted from the complex frequency domain to the time domain by an inverse Laplace transform to obtain a closed-loop gain time domain function h(t):

[0091] Where γ is the real part of all singular points greater than H(s), j is an imaginary number, and j 2 = -1; T is the upper limit of integration. When T tends to infinity, the integration path covers the entire complex frequency domain, t∈[0,T]; nT D =T, n = 0, 1, 2, ....; T D =T on +T off , T D is a PWM control signal cycle, T on Account for T D The ratio is the duty cycle D of the PWM control signal, that is, D = T on / T D =T on / T on +T off ;

[0092] S52: Based on the closed-loop gain time domain function h(t), solve the monitoring time range T m The output voltage V is regulated by the PWM signal. o,adj :

[0093] Among them, t0 is the start time of monitoring time, V cc is the DC input voltage applied to the steady-state circuit;

[0094] S53: Construct the optimal duty cycle model for solving the PWM control signal:

[0095] Among them, V o,ex is the ideal output voltage;

[0096] S54: Optimal duty cycle D obtained by solving step S53 best , and then bring it into step S4 and step S5 to calculate the closed-loop gain H with the optimal duty cycle best (s), and further obtain the regulated output voltage with the optimal duty cycle

[0097] S55: Calculate the PWM signal to adjust the output voltage termination threshold Thr V :

[0098]

[0099] Preferably, the input voltage V applied to the steady-state circuit cc 12V~30V, input current I cc >100mA.

[0100] like Figure 3 (a) and Figure 3 (b) shows the output voltage V of the voltage stabilizing circuit after the PWM control signal is regulated by the method of the present invention when the duty cycle is 15% and 25%, respectively. o,adj and output current I o,adj , Figure 4 (c) and Figure 4 (d) When the duty ratio is 35% and 40%, respectively, the output voltage V after the PWM control signal is regulated by the voltage stabilization circuit using the method of the present invention o,adj and output current I o,adj .

[0101] like Figure 5 As shown, the output voltage V obtained by using the method of the present invention and the convolutional neural network CNN method when the duty cycle D is 15%, 25%, 35% and 40% respectively. o,adj With the ideal output voltage V o,ex The error (vertical axis) increases with the output voltage V o,adj The change within 0V-10V is determined by Figure 5 It can be seen that with the increase of duty cycle, the output error is relatively large. Compared with the same optimization method with a small duty cycle, the output voltage error is higher. In addition, no matter what the duty cycle is, the output voltage V optimized by the method of the present invention is o,adj Compared to the ideal output voltage V o,ex The error is lower than the output voltage optimized by the CNN method of the oil production worker. Compared with the ideal output voltage Vo,ex of error.

[0102] like Figure 6 As shown, the output voltage V obtained by using the method of the present invention and the genetic neural network GA method when the duty cycle D is 15%, 25%, 35% and 40% respectively. o,adj With the ideal output voltage V o,ex The error (vertical axis) increases with the output voltage V o,adj The overall trend of the changes within 0V-10V is the same as the comparison between the method of the present invention and the CNN method.

[0103] It can be seen that the output voltage V o,adj Compared to the ideal output voltage V o,ex The error is lower than the optimization method of the existing technology. Through the calculation function of the LM358 module, the PWM signal can be accurately adjusted, which can effectively improve the precision and accuracy of voltage regulation. The system can still achieve efficient voltage regulation control at a lower switching frequency, reducing switching losses and electromagnetic interference. In addition, the LM358 module can also monitor and feedback the output voltage to achieve automatic adjustment of the system under different working conditions, further improving the stability and efficiency of the system.

[0104] The present invention also provides a PWM signal voltage stabilization system based on the LM358 module for executing the above method, Figure 7 As shown, it includes an EP32 main control module 1 and a PWM signal to voltage module 2 including an LM358 module 25;

[0105] EP32 main control module 1, used for PWM control of the output voltage of the PWM signal to voltage module; the PWM signal to voltage module 2 includes a first green terminal row 21, a second green terminal row 22, a third green terminal row 23 and a PWM signal jumper cap 24; the PWM signal jumper cap 24 includes a first PWM peak jumper wiring area 241 and a second PWM peak jumper wiring area 242; the first PWM peak jumper wiring area 241 is located on the upper side of the PWM jumper cap 24 and is connected to the pins such as Figure 7 The pins on the right above the four pins in the pink frame are as shown. Figure 7 The left and right pins framed by the green wire frame in the pink wire frame; the second PWM peak jumper wiring area 242 is as shown in Figure 8 , Fig. 9 The upper and lower pins of the PWM signal jumper cap 24 are as shown in FIG. Figure 7 The upper and lower pins are framed by the orange wireframe on the left side of the pink area.

[0106] The two pins of the first PWM peak jumper wiring area 241 are used to insert the PWM signal jumper cap 24 into the area where the two pins of the first PWM peak jumper wiring area 241 are located when the peak value of the PWM control signal output from the EP32 main control module 1 to the PWM signal conversion module 2 is in the range of 4.5V-10V. When the peak value of the PWM control signal output from the EP32 main control module 1 to the PWM signal conversion module 2 is in the range of 12V-24V, the PWM signal jumper cap 24 is inserted into the area where the two pins of the second PWM peak jumper wiring area 242 are located.

[0107] The EP32 main control module 1 is connected to the positive and negative poles of the first green terminal row 21 of the PWM signal to voltage module 2, specifically, the negative pole of the second green terminal row 22 is connected to the GND pin on the upper left side of the EP32 main control module 1 and then grounded, and the positive pole of the second green terminal row 22 is connected to the IO2 pin (i.e., GIPO pin) on the left side of the EP32 main control module 1 to receive the PWM control signal transmitted to it by the EP32 main control module 1.

[0108] The present invention also provides a PWM signal voltage stabilizing circuit based on the LM358 module applied to the system as described above. Fig.10 As shown, the circuit is arranged on the PWM signal to voltage module 2, and the circuit includes a first capacitor C1, a first resistor R1, a second capacitor C2, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third capacitor C3, a first diode D1, a second diode D2, and a MOSFET tube Q1 as a source-drain switch;

[0109] like Fig.11As shown, it is a schematic diagram of the structure of eight pins of two operational amplifiers inside the LM358 module. The pin 1 (output end of the operational amplifier 1) of the LM358 module in the voltage stabilizing circuit of the present invention is led out through the first line 11, and is connected in series with the second resistor R2 and the second capacitor C2 in sequence through the first line branch 111, and is connected in series with the fourth resistor R4 through the first line branch 2 112; the other end of the second capacitor C2 is connected to the pin 3 (the in-phase input end of the operational amplifier 1) of the LM358 module through the second line 12 branch 121, and is respectively connected to the first resistor R1 and the first capacitor C1 through the second line 12 branch 122, and the first resistor R1 and the first capacitor C1 are connected in parallel and then grounded; the pin 2 (the inverting input end of the operational amplifier 1) of the LM358 module is led out through the third line 13, and is connected to the third resistor R3 through the third line branch 131, and is led out again through the third line branch 2 132, and is respectively connected to the other end of the fourth resistor R4 one end and the fifth resistor R5; the other end of the third resistor R3 is connected to the ground end in parallel with the first resistor R1 and the first capacitor C1 and is grounded together; the fourth resistor R4 is connected to the first line branch 2 112 at one end and is also tapped to lead out the fourth line 14, which is respectively connected to the anode of the first diode D1 and the cathode of the second diode D2; the anode of the second diode D2 is connected to the sixth resistor R6 and then converged to lead out a tap to be connected to one end of the third capacitor C3 and grounded; the other end of the sixth resistor R6 is converged with the anode of the first diode D1 and then connected to the other end of the third capacitor C3, and connected to the gate of the MOSFET tube Q1, the drain of the MOSFET tube Q1 is connected to the other end of the third resistor R5, and the source of the MOSFET tube Q1 is grounded together with the ground end of the third capacitor C3; the pin 1 of the LM358 module is connected to the positive electrode of the first green terminal 21 of the PWM signal to voltage module through the first line 11, and the output is the adjusted output voltage with the optimal duty cycle obtained in step S6 of the above method. The negative electrode of the first green terminal 21 is grounded;

[0110] Pin 8 (positive power supply terminal) of the LM358 module 1 is connected to the 12V-30V external power supply VCC pin (positive voltage power supply terminal) through the positive pole of the third green terminal row 23, and pin 4 (negative power supply terminal) is connected to the 12V-30V external power supply VEE pin (negative voltage power supply terminal) through the negative pole of the third green terminal row 23; Pin 5 (non-inverting input terminal of the operational amplifier 2) of the LM358 module is used to connect the positive pole of the second green terminal row 22 of the PWM signal to the GIPO2 pin of the EP32 main control module to receive the PWM control signal, and Pin 6 (inverting input terminal of the operational amplifier 2) of the LM358 module is used to connect to the GND pin of the EP32 main control module through the negative pole of the second green terminal row 22 and then be grounded to realize the input of the reference voltage for comparison required for PWM control; Pin 7 (output terminal of the operational amplifier 2) of the LM358 module 1 is then connected to Pin 6 through an external resistor to form a feedback network for the PWM control signal to optimize the duty cycle of the PWM control signal output;

[0111] Among them, the first resistor R1, the second resistor R2, the first capacitor C1 and the second capacitor C2 form a positive feedback circuit; when the MOSFET tube Q1 is turned on, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 form a negative feedback circuit; when the MOSFET tube Q1 is turned off, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the third capacitor C3, the first diode D1 and the second diode D2 form a negative feedback circuit.

[0112] Furthermore, the capacitance values ​​of the first capacitor C1 and the second capacitor are both 10nF, the capacitance value of the third capacitor is 2μF, the resistance values ​​of the first resistor R1, the second resistor R2 and the fifth resistor R5 are all 47kΩ, the resistance value of the third resistor R3 is 10kΩ, the resistance value of the fourth resistor R4 is 19kΩ, the resistance value of the sixth resistor R6 is 1MΩ, and the source-drain switch MOSFET tube Q1 is an N-channel MOSFET tube.

[0113] The system provided by the present invention and the voltage stabilizing circuit thereof can convert the PWM control signal into an analog voltage signal. Specifically, the PWM digital signal is converted into a 0 to 10V analog signal. The output voltage can be adjusted by adjusting the duty cycle of the PWM, which can be used for signal interface switching of PLC or other industrial control boards. The module size is small and easy to be applied in different places. When the input PWM control signal is a peak value of 4.5V to 10V level, this type of level signal is mainly for conventional industrial control cards (such as MACH3 boards). When the input PWM control signal is 12-24V, this type of level signal is mainly for conventional PLC interfaces. Through the precise operational amplification function of the LM358 module, combined with the feedback regulation circuit, more precise control can be achieved between input and output. The low power consumption characteristics and strong operational amplification capability of the LM358 module can ensure that the system can still maintain good output stability under high load conditions, avoiding the voltage drop or overshoot problems that occur in the dynamic change process of the traditional PWM voltage stabilizing circuit.

[0114] In addition, by using the LM358 module combined with PWM signal modulation, it can not only simplify the circuit design and reduce the overall cost, but also improve the anti-interference ability of the system to a certain extent. As an operational amplifier, the LM358 module has the characteristics of high input impedance and low output impedance, which enables it to effectively reduce interference in a high noise environment and improve the anti-noise performance of the system, thereby ensuring the stable operation of the voltage stabilization system in a complex environment.

[0115] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A PWM signal voltage stabilization method based on the LM358 module, wherein the MOSFET tube Q1 is used to adjust whether it is turned on or not according to the magnitude of the output voltage, and the closed-loop gain of the negative feedback circuit to the output voltage is dynamically adjusted, thereby coordinating the negative feedback circuit to stabilize the output voltage, and the method is characterized in that: The following steps are involved: S1: Real-time monitoring of the output voltage V of the PWM signal voltage regulator circuit with LM358 module o size; S2: According to the output voltage V of the LM358 module o The magnitude of the output voltage maximum threshold V o,max The half of the comparison result is used to dynamically adjust the conduction or cutoff of the MOSFET tube Q1 as the source-drain switch, and then dynamically adjust the negative feedback coefficient to complete the adjustment of the contribution of the negative feedback voltage to the output voltage; S3: Calculate the negative feedback voltage V output by the negative feedback circuit according to whether the MOSFET tube Q1 is turned on. n The negative feedback coefficient β n , and further calculate the positive feedback voltage V output by the positive feedback circuit p The positive feedback coefficient β p ; S4: Output the PWM control signal to the voltage stabilizing circuit according to the comparison between the PWM control signal output by the EP32 main control module and the reference signal, and determine the PWM high level duration T according to the duty cycle of the PWM control signal. on And low level duration T off , further construct the positive feedback voltage gain function H p (s) and the negative feedback voltage gain function H n (s) calculation model, thereby obtaining the closed-loop gain H(s) of the voltage stabilizing circuit; S5: Calculate the output voltage value V of the voltage stabilizing circuit according to the closed-loop gain H(s) of the voltage stabilizing circuit o,adj , solve the optimal duty cycle of the PWM control signal, and calculate the PWM signal to adjust the output voltage termination threshold Thr V ; S6: Determine Thr V Is it less than 0.21? If so, the output voltage is adjusted to have the optimal duty cycle. Otherwise, repeat S1-S5 to stabilize the output voltage at (0, V o,max ] threshold range, V o,max is the maximum output voltage threshold.

2. The PWM signal voltage stabilization method based on the LM358 module according to claim 1 is characterized in that: In the step S2, when When the oscillation signal in the voltage stabilizing circuit is too small, the MOSFET tube Q1 is controlled to be turned on, and then the sixth resistor R6 and the third capacitor C3 are grounded. At this time, the first diode D1 and the second diode D2 are not turned on, and only the third resistor R3, the fourth resistor R4 and the fifth resistor R5 form a negative feedback circuit and output a negative feedback voltage V n The output voltage V o Make dynamic adjustments; when When the oscillation signal in the voltage stabilizing circuit is too large, the MOSFET tube Q1 is controlled to be cut off, and then the sixth resistor R6 and the third capacitor C3 participate in the feedback circuit. At this time, the first diode D1 and the second diode D2 are turned on, dynamically adjusting the influence of the negative feedback circuit on the output voltage.

3. The PWM signal voltage stabilization method based on the LM358 module according to claim 1 is characterized in that: When the MOSFET tube Q1 is turned on, the negative feedback voltage V output by the negative feedback circuit is calculated in step S3. n The negative feedback coefficient β n as follows: Among them, R3, R4 and R5 are the resistance values ​​of the third resistor R3, the fourth resistor R4 and the fifth resistor R5 respectively. When the MOSFET tube Q1 is turned off, the negative feedback coefficient β of the negative feedback voltage n as follows: Among them, Z n is the impedance formed by the sixth resistor R6 and the third capacitor R3, R6 is the resistance value of the sixth resistor R6, C3 is the capacitance value of the third capacitor C3; j is an imaginary number, ω is the angular frequency of the PWM control signal, ω=2πf, f is the sinusoidal wave frequency of the PWM control signal, f=D / T on , D is the duty cycle of the PWM control signal.

4. The PWM signal voltage stabilization method based on the LM358 module according to claim 3 is characterized in that: In step S3, the positive feedback voltage V output by the positive feedback circuit is calculated. p The positive feedback coefficient β p The formula is as follows: Wherein, R1 and R2 are resistance values ​​of the first resistor R1 and the second resistor R2 respectively, and C1 and C2 are capacitance values ​​of the first capacitor C1 and the second capacitor C2 respectively.

5. The PWM signal voltage stabilization method based on the LM358 module according to claim 1 is characterized in that: The positive feedback voltage gain function H constructed in step S4 is p (s) and the negative feedback voltage gain function H n (s) The calculation models are as follows: Among them, φ o K is the initial phase angle of the output voltage of pin 1 of the LM358 module; p (s) is the gain coefficient of the positive feedback voltage on the duty cycle of the PWM control signal, K n (s) is the gain coefficient of negative feedback voltage to PWM signal duty cycle adjustment; Wherein, s is the unit variable analyzed in the complex frequency domain of the voltage stabilizing circuit, s=1 / (jw); The closed-loop gain H(s) of the voltage stabilizing circuit is as follows:

6. The PWM signal voltage stabilization method based on the LM358 module according to claim 1 is characterized in that: The S5 step includes: S51: The closed-loop gain transfer function H(s) is converted from the complex frequency domain to the time domain by an inverse Laplace transform to obtain a closed-loop gain time domain function h(t): Where γ is the real part of all singular points greater than H(s), j is an imaginary number, and j 2 = -1; T is the upper limit of integration. When T tends to infinity, the integration path covers the entire complex frequency domain, t∈[0,T]; nT D =T, n = 0, 1, 2, ....; T D =T on +T off , T D is a PWM control signal cycle, T on Account for T D The ratio is the duty cycle D of the PWM control signal, that is, D = T on / T D =T on / T on +T off ; S52: Based on the closed-loop gain time domain function h(t), solve the monitoring time range T m The output voltage V is regulated by the PWM signal. o,adj : Among them, t0 is the start time of monitoring time, V cc is the DC input voltage applied to the steady-state circuit; S53: Construct the optimal duty cycle model for solving the PWM control signal: V o,ex is the ideal output voltage; S54: Optimal duty cycle D obtained by solving the above step S53 best , is brought into the S4 and S5 steps to calculate the closed-loop gain H with the optimal duty cycle best (s), and further obtain the regulated output voltage with the optimal duty cycle S55: Calculate the PWM signal to adjust the output voltage termination threshold Thr V :

7. The PWM signal voltage stabilization method based on the LM358 module according to claim 6 is characterized in that: The input voltage V applied to the steady-state circuit cc 12V~30V, input current I cc >100mA.

8. A PWM signal voltage stabilization system based on an LM358 module that implements the method as described in any one of claims 1 to 7, characterized in that: It includes an EP32 main control module (1) and a PWM signal to voltage module (2) including an LM358 module (25); The EP32 main control module (1) is used for PWM control of the output voltage of the PWM signal-to-voltage module; the PWM signal-to-voltage module (2) comprises a first green terminal row (21), a second green terminal row (22), a third green terminal row (23) and a PWM signal jumper cap (24); the PWM signal jumper cap (24) comprises a first PWM peak value jumper wiring area (241) and a second PWM peak value jumper wiring area (242); The EP32 main control module (1) is connected to the positive and negative electrodes of the second green terminal block (22) of the PWM signal-to-voltage module (2).

9. A PWM signal voltage stabilizing circuit based on an LM358 module applied to the system as claimed in claim 8, wherein the circuit is arranged on the PWM signal to voltage conversion module (2), and is characterized in that: The circuit includes a first capacitor C1, a first resistor R1, a second capacitor C2, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third capacitor C3, a first diode D1, a second diode D2 and a MOSFET tube Q1 as a source-drain switch; Pin 1 of the LM358 module is led out through the first line (11), connected in series with the second resistor R2 and the second capacitor C2 in sequence through the first line branch one (111), and connected in series with the fourth resistor R4 through the first line branch two (112); the other end of the second capacitor C2 is connected to pin 3 of the LM358 module through the second line branch one (121), and connected to the first resistor R1 and the first capacitor C1 respectively through the second line branch two (122), and the first resistor R1 and the first capacitor C1 are connected in parallel and then grounded; pin 2 of the LM358 module is led out through the third line (13), and connected to the third resistor R3 through the third line branch one (131), and led out again through the third line branch two (132), and connected to the other end of the fourth resistor R4 and the fifth resistor R5 respectively; the other end of the third resistor R3 is connected in parallel with the first resistor R1 and the first capacitor C1 and is grounded together, and the fourth The resistor R4 is connected to the first line branch 2 (112) at one end and is also tapped out to lead out a fourth line (14) connected to the anode of the first diode D1 and the cathode of the second diode D2 respectively; the anode of the second diode D2 is connected to the sixth resistor R6 and then converged to lead out a tap to be connected to one end of the third capacitor C3 and grounded; the other end of the sixth resistor R6 is converged with the anode of the first diode D1 and then connected to the other end of the third capacitor C3 and connected to the gate of the MOSFET tube Q1; the drain of the MOSFET tube Q1 is connected to the other end of the third resistor R5; the source of the MOSFET tube Q1 and the ground end of the third capacitor C3 are grounded together; the pin 1 of the LM358 module is connected to the positive electrode of the first green terminal block (21) of the PWM signal to voltage module through the first line (11), and outputs the adjusted output voltage with the optimal duty cycle obtained in the step S6 of the method according to any one of claims 1 to 7 The negative electrode of the first green terminal block (21) is grounded; Pin 8 of the LM358 module (25) is connected to the 12V-30V external power supply VCC pin through the positive pole of the third green terminal row (23), and pin 4 of the LM358 module (25) is connected to the 12V-30V external power supply VEE pin through the negative pole of the third green terminal row (23); pin 5 of the LM358 module is used to be connected to the GIPO2 pin of the EP32 main control module through the positive pole of the second green terminal row of the PWM signal to voltage module, and is used to receive the PWM control signal; pin 6 of the LM358 module (25) is used to be connected to the GND pin of the EP32 main control module (1) through the negative pole of the second green terminal row (22) and then be grounded together, so as to realize the input of the reference voltage for comparison required for PWM control; pin 7 of the LM358 module (25) is then connected to pin 6 of the LM358 module (25) through an external resistor, so as to form a feedback network for the PWM control signal and optimize the duty cycle of the PWM control signal output; Among them, the first resistor R1, the second resistor R2, the first capacitor C1 and the second capacitor C2 form a positive feedback circuit; when the MOSFET tube Q1 is turned on, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 form a negative feedback circuit; when the MOSFET tube Q1 is turned off, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the third capacitor C3, the first diode D1 and the second diode D2 form a negative feedback circuit.

10. The PWM signal voltage stabilizing circuit based on the LM358 module according to claim 9 is characterized in that: The capacitance values ​​of the first capacitor C1 and the second capacitor are both 10nF, the capacitance value of the third capacitor is 2μF, the resistance values ​​of the first resistor R1, the second resistor R2 and the fifth resistor R5 are all 47kΩ, the resistance value of the third resistor R3 is 10kΩ, the resistance value of the fourth resistor R4 is 19kΩ, the resistance value of the sixth resistor R6 is 1MΩ, and the source-drain switch MOSFET tube Q1 is an N-channel MOSFET tube.

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