A control system and method for a laser driver power supply

Abstract

The application discloses a kind of control system and method of laser driver power supply, wherein the system includes digital control module and analog control module;The digital control module is used to obtain the output current value of the laser driver power supply in real time, the output current value is compared with current given value, and the duty cycle output modulation is carried out by PID controller in combination with comparison difference, and the modulated duty cycle is input to the analog control module in turn after photoelectric isolator and low-pass filter;The analog control module is used to correct the output current of the laser driver power supply according to the modulated duty cycle, and combines the advantages of digital control and analog control respectively, improves control accuracy and response time, and is not affected by environmental factors such as temperature and humidity, to realize the output of laser driver power supply with high precision, fast response and strong anti-interference.

Description

Technical Field

[0001] The present invention belongs to the technical field of driving power supplies, and in particular relates to a control system and method for a laser driving power supply. Background Art

[0002] Semiconductor lasers are increasingly used due to their advantages of ultra-small size, high efficiency, simple structure and low price. The excitation method of semiconductor lasers usually adopts the form of current injection. The output power of the laser can be controlled by changing the injection current of the semiconductor laser. The constant current source drive is the most commonly used method.

[0003] In existing technologies, laser driver power supplies generally use pure digital control or pure analog control. Pure digital control offers advantages such as good anti-interference, flexibility, and compatibility, but also has disadvantages such as control loop bandwidth being limited by the control frequency and slow dynamic response. Pure analog control offers advantages such as good control response speed and control accuracy, but is significantly affected by the environment. When factors such as temperature and humidity cause changes in load or hardware setpoints, the analog control output becomes inaccurate, resulting in deviations in the laser's optical power. Therefore, how to avoid the drawbacks of pure digital control or pure analog control is an urgent problem to be solved. Summary of the Invention

[0004] The present invention provides a control system and method for a laser driving power supply, which are used to solve the problem of how to avoid the defects of pure digital control or pure analog control.

[0005] In order to solve the above technical problems, the present invention provides a control system for a laser driving power supply, comprising a digital control module and an analog control module;

[0006] The digital control module is used to obtain the output current value of the laser driving power supply in real time, compare the output current value with the current set value, and perform duty cycle output modulation based on the comparison difference through a PID controller. The modulated duty cycle is sequentially input into the analog control module after passing through an optoelectronic isolator and a low-pass filter;

[0007] The analog control module is used to perform deviation correction on the output current of the laser driving power supply according to the modulated duty cycle.

[0008] Furthermore, it also includes a photoelectric isolator compensation feedback circuit arranged between the digital control module and the photoelectric isolator;

[0009] The optoelectronic isolator is a dual-source optoelectronic isolator, which includes a light-emitting part, a first edge receiving part, and a second edge receiving part. The second edge receiving part is used to connect to the optoelectronic isolator compensation feedback circuit. By converting the current value of the second edge receiving part and combining it with the given current value of the second edge receiving part, the duty cycle output of the digital control module is compensated and corrected.

[0010] Furthermore, it also includes an analog control compensation module;

[0011] The analog control compensation module is used to obtain a plurality of input voltages of the laser driving power supply within a time period, and to perform a subtraction between the plurality of input voltage values ​​and the plurality of input voltage values ​​obtained within a previous time period through the digital control module. When the difference exceeds a threshold, a duty cycle value to be compensated is obtained through a proportional operation;

[0012] The current given feedback proportional coefficient N is set, and the analog control module compensates and corrects the output current of the laser driving power supply by adjusting the value of N according to the duty cycle value that needs to be compensated.

[0013] Furthermore, the output current value is compared with a current set value, and duty cycle output modulation is performed by combining the comparison value with a PID controller, including:

[0014] When the temperature rises, the current of the photoelectric isolator increases, the analog set value input to the analog control module after filtering by the low-pass filter increases, the output current value of the laser driving power supply increases compared to the current set value, and the duty cycle output is reduced by the PID controller;

[0015] When the temperature drops, the current of the photoelectric isolator decreases, the analog set value of the analog control module after filtering by the low-pass filter decreases, the output current value of the laser driving power supply decreases compared to the current set value, and the duty cycle output is increased by the PID controller.

[0016] Furthermore, after comparing the output current with a given current value and performing duty cycle output modulation by a PID controller in combination with the comparison value, the method further includes:

[0017] The current given feedforward proportional coefficient M is set, and the duty cycle output is performed by adjusting the value of M and superimposing the PID controller.

[0018] Furthermore, the photoelectric isolator compensation feedback circuit includes a first voltage-dividing resistor, a second voltage-dividing resistor, and a filter capacitor;

[0019] The filter capacitor, the first voltage-dividing resistor and the second side receiving part are connected in parallel, the second voltage-dividing resistor and the first voltage-dividing resistor are connected in series and then connected to the power supply voltage, the voltage value of the filter capacitor is obtained in real time, and the voltage value is transmitted to the digital control module.

[0020] Furthermore, it also includes:

[0021] Converting the second side receiving portion current value If, ​​combining it with the second side receiving portion given current value, and compensating and correcting the output duty cycle of the digital control module by the difference between the second side receiving portion current value If and the second side receiving portion given current value;

[0022]

[0023] Among them, VR1 is the real-time voltage value of the filter capacitor, R1 is the first voltage-dividing resistor, R2 is the second voltage-dividing resistor, and VCC is the power supply voltage.

[0024] The present invention also provides a method for controlling a laser driving power supply, comprising the following steps:

[0025] Obtain the output current value of the laser driving power supply in real time;

[0026] Comparing the output current value with the current set value, and performing duty cycle output modulation based on the comparison difference through a PID controller;

[0027] Deviation correction is performed on the output current of the laser driving power supply according to the modulated duty cycle.

[0028] Furthermore, it also includes:

[0029] Performing photoelectric isolator compensation on a photoelectric isolator, wherein the photoelectric isolator is a dual-receiving source photoelectric isolator, and the dual-receiving source photoelectric isolator includes a light-emitting part, a first edge receiving part, and a second edge receiving part, and the second edge receiving part is connected to a photoelectric isolator compensation feedback circuit;

[0030] The current value of the second receiving portion is converted and combined with the given current value of the second receiving portion to compensate and correct the duty cycle output of the digital control module.

[0031] Furthermore, it also includes:

[0032] Acquiring a plurality of input voltages of the laser driving power supply within a time period;

[0033] Subtracting the plurality of input voltage values ​​from the plurality of input voltage values ​​obtained in the previous time period, and obtaining a duty cycle value that needs to be compensated by performing a proportional operation when the difference exceeds a threshold;

[0034] The output current of the laser driving power supply is compensated and corrected according to the duty cycle value that needs to be compensated.

[0035] Compared with the existing technology, the control system and method of a laser driving power supply provided by the present invention combine the respective advantages of digital control and analog control, effectively avoiding the problems of laser light output deviation caused by the temperature of the optoelectronic isolator and the laser's inability to respond quickly due to the internal resistance of the battery. While improving the control accuracy and response time, it is not affected by environmental factors such as temperature and humidity, and realizes high-precision, fast-response, and strong anti-interference laser driving power supply output. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] 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 only part of the embodiments of the present invention, rather than all the embodiments. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings are all within the scope of protection of this application.

[0037] Figure 1 This is a schematic diagram of a digital-analog control structure of a control system for a laser driving power supply provided by an embodiment of the present invention;

[0038] Figure 2 This is a schematic structural diagram of temperature compensation of a control system for a laser driving power supply provided by an embodiment of the present invention;

[0039] Figure 3 This is an overall block diagram of a control system for a laser driving power supply provided by an embodiment of the present invention;

[0040] Figure 4 This is a graph showing changes in temperature of a photoelectric isolator in a control system of a laser driving power supply provided by an embodiment of the present invention;

[0041] Figure 5 This is a schematic structural diagram of a photoelectric isolator of a control system for a laser driving power supply provided by an embodiment of the present invention;

[0042] Figure 6 This is a schematic structural diagram of a photoelectric isolator compensation feedback circuit of a control system of a laser driving power supply provided by an embodiment of the present invention;

[0043] Figure 7 This is a linear compensation diagram of a secondary side receiving portion of a control system of a laser driving power supply provided by an embodiment of the present invention;

[0044] Figure 8 This is a circuit diagram of a control system for a laser driving power supply provided by an embodiment of the present invention;

[0045] Figure 9 This is a diagram of the output characteristics of a battery in a circuit diagram of a control system for a laser driving power supply provided by an embodiment of the present invention;

[0046] Figure 10 This is a flow chart of a method for controlling a laser driving power supply provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] In order to make the description of the present disclosure more detailed and complete, the following is an illustrative description of the implementation methods and specific examples of the present invention; however, this is not the only form of implementing or using the specific embodiments of the present invention. The implementation methods cover the features of multiple specific embodiments and the method steps and their sequence for constructing and operating these specific embodiments. However, other specific embodiments can also be used to achieve the same or equal functions and step sequences. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0049] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be practiced in an order other than that illustrated or described herein.

[0050] In the description of the embodiments of the present invention, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is merely a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two, and other quantifiers are similar. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention, and the embodiments of the present application and the features in the embodiments can be combined with each other unless there is a conflict.

[0051] Please refer to Figures 1-9, to solve the problem of how to avoid the defects of pure digital control or pure analog control. The embodiment of the present invention provides a control system for a laser driving power supply, please refer to Figure 1 , which is a schematic diagram of the digital-analog control structure of a control system for a laser driving power supply provided in an embodiment of the present invention. The control system includes a digital control module and an analog control module. Information is transmitted between the digital control module and the analog control module through an optoelectronic isolator and a low-pass filter.

[0052] However, optoelectronic isolators are sensitive to temperature and are greatly affected by temperature. Please refer to Figure 4 , which is a curve diagram of the change of the optoelectronic isolator with temperature in a control system of a laser driving power supply provided by an embodiment of the present invention. In the figure, the horizontal axis represents the device temperature, and the vertical axis represents the current of the light-emitting part. We can observe that when the circuit parameters remain unchanged, the current of the light-emitting part of the optoelectronic isolator continues to increase with the change of temperature, which will cause the transferred energy to change accordingly. When the output current of the optoelectronic isolator changes, the analog set value provided to the analog control module by the subsequent stage will also change, which will eventually lead to the instability of the overall output of the driving power supply. Therefore, the embodiment of the present invention collects the output current of the laser driving power supply in real time through the digital control chip set in the digital control module, and then corrects the deviation caused by temperature through the PID controller.

[0053] In order to further reduce the impact of temperature changes on the driving power supply, the embodiment of the present invention uses a digital control chip set in the digital control module to collect the output current of the laser driving power supply in real time, compares the collected output current with a given reference value, i.e., a given current value, and outputs a PWM (Pulse Width Modulation) duty cycle after modulation by a PID controller.

[0054] It should be noted that the above-mentioned PID controller (Proportion Integration Differentiation) is composed of a proportional unit, an integral unit and a differential unit. It is mainly used for systems that are basically linear and whose dynamic characteristics do not change with time. When the output current value differs from the given current value, proportional adjustment (that is, the output control amount is proportional to the deviation value) and integral adjustment (that is, the output control amount is proportional to the integral of the deviation value) will be automatically performed according to the size of the deviation and the positive and negative characteristics. Since the specific application of PID controllers in this field is very mature, the embodiment of the present invention does not elaborate on how to modulate the duty cycle output through the PID controller. Those skilled in the art should know this.

[0055] Furthermore, after the output current and the current set value are modulated by the PID controller to output the duty cycle, the output duty cycle is input into the analog control module after passing through the optoelectronic isolator and the low-pass filter in turn, that is, the analog control module is implemented to simulate the set value.

[0056] The specific correction process of the PID controller is as follows: when the temperature rises, the current of the optoelectronic isolator increases, and its output is filtered by a low-pass filter and input to the analog control module. The analog given value increases, causing the output current value of the laser to increase compared to the current given value. At this time, it is necessary to modulate the increased current through the PID controller to reduce the duty cycle output, that is, further reduce the analog given value, thereby achieving deviation correction modulation of the output current value when the temperature rises; when the temperature drops, the current of the optoelectronic isolator decreases, and its output is filtered by a low-pass filter and input to the analog control module. The analog given value is smaller, causing the output current value of the laser to be smaller than the current given value. At this time, it is necessary to modulate the smaller current through the PID controller to increase the duty cycle output, that is, further increase the analog given value, thereby achieving deviation correction modulation of the output current value when the temperature drops.

[0057] In an embodiment of the present invention, in order to speed up the output response speed, after the output current and the current set value are modulated by the PID controller to output the duty cycle, it also includes setting the current set feedforward proportional coefficient M, and adjusting the value of the M to superimpose the PID controller to output the duty cycle; by adjusting the size of M, the output speed can be accelerated or slowed down, and the analog set value is superimposed with the duty cycle output of the PID controller to jointly control the analog set value, which to a certain extent reduces the modulation pressure of the PID controller.

[0058] The control system of the laser driving power supply proposed in the embodiment of the present invention is suitable for the correction of slowly changing current deviations. However, due to the large delay in the application of the low-pass filter, there will be a large control hysteresis and it cannot adapt to the correction of rapidly changing current deviations. Please refer to Figure 2 , which is a structural diagram of temperature compensation of a control system of a laser driving power supply provided by an embodiment of the present invention. In the embodiment of the present invention, an optoelectronic isolator compensation feedback circuit is further provided between the digital control module and the optoelectronic isolator to adapt to the current deviation correction during rapid changes, and further reduce the nonlinear influence of the output current of the driving power supply caused by the optoelectronic isolator due to temperature changes.

[0059] For details, please refer to Figure 5, which is a structural schematic diagram of a photoelectric isolator for a control system of a laser driving power supply provided in an embodiment of the present invention. In this embodiment of the present invention, the photoelectric isolator uses a dual-receiving source photoelectric isolator, wherein SD1 is the light-emitting part, RT1 is the first side receiving part, and the above-mentioned first side receiving part is used to transmit to the digital control module and then to the subsequent stage to jointly control the analog given value. RD2 is the second side receiving part, which is used as the compensation detection part and is used to connect to the compensation feedback circuit of the above-mentioned photoelectric isolator.

[0060] For further information, please refer to Figure 6 , which is a structural diagram of a photoelectric isolator compensation feedback circuit of a control system of a laser driving power supply provided by an embodiment of the present invention, the above-mentioned photoelectric isolator compensation feedback circuit includes a first voltage-dividing resistor R1, a second voltage-dividing resistor R2, and a filter capacitor C, wherein the filter capacitor C and the first voltage-dividing resistor R1 are both connected in parallel with the above-mentioned second side receiving part RD2, VCC is the power supply voltage, VR1 is the real-time voltage value of the filter capacitor, R1 is the first voltage-dividing resistor, R2 is the second voltage-dividing resistor, the second voltage-dividing resistor R2 is connected in series with the first voltage-dividing resistor R1 and then connected to the power supply voltage VCC, obtains the real-time voltage value VR1 of the filter capacitor and transmits this part of the voltage value to the AD sampling port of the digital controller in the digital control module; since SD1, RD2, and RT1 are all partial structures in the above-mentioned dual-receiving source photoelectric isolator, their temperatures are basically the same, and the change of the SD1 current value can be linearly reflected by the current value of RD2.

[0061] In the embodiment of the present invention, please refer to Figure 7 , which is a linear compensation diagram of the second side receiving part of the control system of a laser driving power supply provided by an embodiment of the present invention. Assuming that the current set value is a certain value, the value of the second side receiving part RD2 should be 7mA. However, the actual received value shows a curve with the temperature change. Therefore, it is necessary to convert the current value of the second side receiving part RD2 and combine it with the set current value of the second side receiving part RD2 to compensate and correct the duty cycle output of the digital control module.

[0062] Specifically, the formula used to convert the current value If of the second side receiving part RD2 is:

[0063]

[0064] Among them, VR1 is the real-time voltage value of the filter capacitor, R1 is the first voltage-dividing resistor, R2 is the second voltage-dividing resistor, and VCC is the power supply voltage.

[0065] Furthermore, the output duty cycle of the digital control module is compensated and corrected by the difference between the current value If of the second side receiving part RD2 and the given current value of the second side receiving part RD2. For example, the converted If value is subtracted from the above-mentioned 7mA to generate a deviation value, and the digital control module compensates and corrects its output duty cycle by the above-mentioned deviation value, and finally makes the If value 7mA.

[0066] The present invention also provides an application example of the control system of the laser driving power supply. Figure 8 , which is an implementation circuit diagram of a control system for a laser driving power supply provided by an embodiment of the present invention, the circuit diagram includes a DC voltage source V, a primary full-bridge circuit, a secondary full-bridge circuit, and an isolation transformer arranged between the primary full-bridge circuit and the secondary full-bridge circuit. The primary full-bridge circuit includes a first bridge arm and a second bridge arm, the first bridge arm includes a first switching device Q1 and a third switching device Q3 connected in series, and the second bridge arm includes a second switching device Q2 and a fourth switching device Q4 connected in series; the secondary full-bridge circuit includes a third bridge arm and a fourth bridge arm, the third bridge arm includes a third rectifier diode D3 and a fourth rectifier diode D4 connected in series, and the fourth bridge arm includes a fifth rectifier diode D5 and a sixth rectifier diode D6 connected in series.

[0067] Furthermore, it also includes a first resonant inductor L1 and a second resonant inductor C2. The like-name end of the primary winding of the above-mentioned isolation transformer is connected to the midpoint of the first bridge arm after passing through the first resonant inductor L1, and the opposite-name end of the primary winding of the isolation transformer is connected to the midpoint of the second bridge arm after passing through the second resonant inductor C2; the like-name end of the secondary winding of the isolation transformer is connected to the midpoint of the third bridge arm, and the opposite-name end of the secondary winding of the isolation transformer is connected to the midpoint of the fourth bridge arm.

[0068] Furthermore, it also includes an input stage filter capacitor C1 connected in parallel at both ends of the first bridge arm and the second bridge arm, an output filter capacitor C3 connected in parallel at the third bridge arm and the fourth bridge arm, and a first clamping diode D1 and a second clamping diode D2, wherein one end of the first clamping diode D1 is connected to the second bridge arm, and the other end is connected to the opposite-name end of the primary winding of the isolation transformer, one end of the second clamping diode D2 is connected to the second bridge arm, and the other end is connected to the same-name end of the primary winding of the isolation transformer, and also includes a laser emitter and an output filter inductor L2, and the above-mentioned laser emitter and output filter inductor L2 are connected in parallel at both ends of the third bridge arm and the fourth bridge arm.

[0069] For further information, please refer to Figure 9, which is a diagram of the output characteristics of the battery in the circuit diagram of the control system implementation of a laser driving power supply provided by an embodiment of the present invention. Since the driving power supply of the entire laser emitter is provided with electrical energy by the battery, when the laser requires rapid light emission or the optical power changes rapidly, the laser driving power supply needs to respond quickly to change the output power. However, due to the internal resistance of the battery, when the output instantaneous power changes rapidly, a large voltage change will be generated at the output interface end, which will eventually lead to unstable output current control of the laser driving power supply, thereby affecting the final light emission effect of the laser.

[0070] Therefore, in order to solve the above problems, the embodiment of the present invention further provides an analog control compensation module based on the above control system. Figure 3 , which is an overall block diagram of a control system of a laser driving power supply provided by an embodiment of the present invention. The analog control compensation module is used to obtain the input voltage value of the laser driving power supply in real time, and sample according to a fixed period. Specifically, at least three of the above input voltage values ​​are obtained. The digital control module subtracts the above input voltage values ​​from the input voltage values ​​obtained in the previous or previous time periods. If the difference is within a very small threshold range, it indicates that the input voltage fluctuation is small and no analog control compensation intervention is required. When the difference exceeds the threshold, it indicates that the input voltage has undergone a large fluctuation and analog control compensation intervention is required. The difference is sent to the proportional operation to obtain the duty cycle value that needs to be compensated, and output to the analog control module for compensation correction.

[0071] Furthermore, the analog control module also sets a current given feedback proportional coefficient N, and the analog control module adjusts the value of N according to the duty cycle value to be compensated, thereby compensating and correcting the output current of the laser driving power supply.

[0072] It should be noted that the circuit diagram provided in the above figure is only a specific embodiment provided to facilitate understanding of the technical solution of the present invention, and does not mean that the technical solution disclosed in the present invention can only be applied to the above circuit diagram. As long as it is necessary to control the laser driving power supply, in order to achieve stable and reliable operation of the laser driving power supply, the above technical solutions of the present invention are all feasible, and the present invention does not impose too many restrictions on this.

[0073] For the control system based on the above laser drive power supply, please refer to Figure 10 , is a flow chart of a method for controlling a laser driving power supply provided by an embodiment of the present invention, the method specifically comprising the following steps:

[0074] S1: obtaining the output current value of the laser driving power supply in real time;

[0075] S2: Compare the output current value with the current set value, and perform duty cycle output modulation based on the comparison difference through a PID controller;

[0076] S3: Correcting the output current of the laser driving power supply according to the modulated duty cycle.

[0077] As an optional implementation, the above method further includes:

[0078] Performing photoelectric isolator compensation on a photoelectric isolator, wherein the photoelectric isolator is a dual-receiving source photoelectric isolator, and the dual-receiving source photoelectric isolator includes a light-emitting part, a first edge receiving part, and a second edge receiving part, and the second edge receiving part is connected to a photoelectric isolator compensation feedback circuit;

[0079] The current value of the second receiving portion is converted and combined with the given current value of the second receiving portion to compensate and correct the duty cycle output of the digital control module.

[0080] As an optional implementation, the above method further includes:

[0081] Acquiring a plurality of input voltages of the laser driving power supply within a time period;

[0082] Subtracting the plurality of input voltage values ​​from the plurality of input voltage values ​​obtained in the previous time period, and obtaining a duty cycle value that needs to be compensated by performing a proportional operation when the difference exceeds a threshold;

[0083] The output current of the laser driving power supply is compensated and corrected according to the duty cycle value that needs to be compensated.

[0084] For other details on implementing the above technical solution in the control method of the above laser driving power supply, please refer to the description of the control system of the laser driving power supply provided in the above invention embodiment, which will not be repeated here.

[0085] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0086] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0087] The present invention provides a control system and method for a laser driving power supply, which combines the respective advantages of digital control and analog control, effectively avoiding the problems of laser light output deviation due to the temperature of the photoelectric isolator and the laser's inability to respond quickly due to the internal resistance of the battery. While improving control accuracy and response time, it is not affected by environmental factors such as temperature and humidity, and realizes high-precision, fast-response, and strong anti-interference laser driving power supply output.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A control system for a laser driving power supply, characterized in that: Including digital control module and analog control module; The digital control module is used to obtain the output current value of the laser driving power supply in real time, compare the output current value with the current set value, and perform duty cycle output modulation based on the comparison difference through a PID controller. The modulated duty cycle is sequentially input into the analog control module after passing through an optoelectronic isolator and a low-pass filter; The analog control module is used to perform deviation correction on the output current of the laser driving power supply according to the modulated duty cycle; It also includes a photoelectric isolator compensation feedback circuit arranged between the digital control module and the photoelectric isolator; the photoelectric isolator is a dual-source photoelectric isolator, and the dual-source photoelectric isolator includes a light-emitting part, a first edge receiving part, and a second edge receiving part. The second edge receiving part is used to connect to the photoelectric isolator compensation feedback circuit, and compensates and corrects the duty cycle output of the digital control module by converting the current value of the second edge receiving part and combining it with the given current value of the second edge receiving part; The step of comparing the output current value with a given current value and modulating the duty cycle output by combining the comparison value with a PID controller includes: When the temperature rises, the current of the photoelectric isolator increases, the analog set value input to the analog control module after filtering by the low-pass filter increases, the output current value of the laser driving power supply increases compared to the current set value, and the duty cycle output is reduced by the PID controller; When the temperature drops, the current of the photoelectric isolator decreases, the analog set value of the analog control module after filtering by the low-pass filter decreases, the output current value of the laser driving power supply decreases compared to the current set value, and the duty cycle output is increased by the PID controller.

2. A laser driving power supply control system as claimed in claim 1, characterized in that: Also included is an analog control compensation module; The analog control compensation module is used to obtain a plurality of input voltage values ​​of the laser driving power supply within a time period, and to perform a subtraction between the plurality of input voltage values ​​and the plurality of input voltage values ​​obtained within a previous time period through the digital control module. When the difference exceeds a threshold, a duty cycle value to be compensated is obtained through a proportional operation; The current given feedback proportional coefficient N is set, and the analog control module compensates and corrects the output current of the laser driving power supply by adjusting the value of N according to the duty cycle value that needs to be compensated.

3. A laser driving power supply control system as claimed in claim 1, characterized in that: After comparing the output current with the current set value and performing duty cycle output modulation based on the comparison value by a PID controller, the method further includes: The current given feedforward proportional coefficient M is set, and the duty cycle output is performed by adjusting the value of M and superimposing the PID controller.

4. A laser driving power supply control system as claimed in claim 1, characterized in that: The photoelectric isolator compensation feedback circuit includes a first voltage-dividing resistor, a second voltage-dividing resistor, and a filter capacitor; The filter capacitor, the first voltage-dividing resistor and the second side receiving part are connected in parallel, the second voltage-dividing resistor and the first voltage-dividing resistor are connected in series and then connected to the power supply voltage, the voltage value of the filter capacitor is obtained in real time, and the voltage value is transmitted to the digital control module.

5. A control system for a laser driving power supply as claimed in claim 4, characterized in that: Converting the second side receiving part current value If, ​​combining the second side receiving part given current value, and compensating and correcting the output duty cycle of the digital control module by the difference between the second side receiving part current value If and the secondary side receiving part given current value; Among them, VR1 is the real-time voltage value of the filter capacitor, R1 is the first voltage-dividing resistor, R2 is the second voltage-dividing resistor, and VCC is the power supply voltage.

6. A method for controlling a laser driving power supply, characterized in that: The following steps are involved: Obtain the output current value of the laser driving power supply in real time; Comparing the output current value with the current set value, and performing duty cycle output modulation based on the comparison difference through a PID controller; performing deviation correction on the output current of the laser driving power supply according to the modulated duty cycle; The invention also includes: performing photoelectric isolator compensation on the photoelectric isolator, wherein the photoelectric isolator is a dual-receiving source photoelectric isolator, and the dual-receiving source photoelectric isolator includes a light-emitting part, a first edge receiving part and a second edge receiving part, and connecting the second edge receiving part to the photoelectric isolator compensation feedback circuit; Converting the current value of the second receiving portion and combining it with the given current value of the second receiving portion to compensate and correct the duty cycle output of the digital control module; and The method further includes: obtaining a plurality of input voltage values ​​of the laser driving power supply within a time period; Subtracting the plurality of input voltage values ​​from the plurality of input voltage values ​​obtained in the previous time period, and obtaining a duty cycle value that needs to be compensated by performing a proportional operation when the difference exceeds a threshold; The output current of the laser driving power supply is compensated and corrected according to the duty cycle value that needs to be compensated.

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