CN110442167A - A kind of temperature control system and its control method in pulse laser seeds source - Google Patents

Abstract

The invention discloses a temperature control system of a pulsed laser seed source and a control method thereof, comprising a power supply module for providing power to the entire device, a fuzzy PID controller and a laser diode; the fuzzy PID controller includes a fuzzy controller and a PID control device; the present invention realizes an economical, effective and stable pulse laser seed source temperature control method by adopting a temperature control system combining fuzzy algorithm and PID control, so the pulse laser seed source can be realized at lower power consumption Temperature change control, so as to ensure the stable output of pulsed laser seed source power, the present invention has high temperature control precision and greatly improved efficiency, and the control system can realize data communication, data processing and system control and other processing functions, with high degree of automation and fast speed , High measurement efficiency, small error, convenient operation and so on.

Description

A temperature control system and control method for a pulsed laser seed source

technical field

The invention relates to the technical field of temperature control, in particular to a temperature control system of a pulsed laser seed source and a control method thereof.

Background technique

With the rapid development of information technology, semiconductor lasers have been widely used in the fields of optical fiber communication, optical fiber sensing and laser radar, etc., and have broad application prospects; however, temperature is one of the main factors affecting the performance of lasers. As the temperature rises, its output wavelength gradually shifts to the long wavelength direction. At the same time, the accuracy of temperature control also affects the line width and power of the laser. Therefore, it is necessary to adopt a suitable temperature control technology for the semiconductor laser to ensure that the semiconductor laser or system can normal work.

The invention patent with the application number 200710045711.0 uses the bridge driver chip to design the drive circuit of the thermoelectric cooler, which realizes the temperature control of the semiconductor laser; the patent application with the application number 201410480407.9 uses the temperature detection designed by the Wheatstone bridge and the operational amplifier The amplifying circuit realizes the temperature control of the semiconductor laser, but the temperature acquisition circuit of these inventions uses an analog circuit, so the temperature acquisition circuit is relatively complicated, mainly because the temperature acquisition circuit uses a bridge circuit, and there is no high The precision algorithm is controlled, so that temperature fluctuations will occur during the temperature control process, resulting in changes in the temperature of the laser, resulting in fluctuations in the output wavelength, line width and power of the laser, which will have a certain impact on its subsequent systems.

PID control is one of the earliest temperature control strategies developed using classical control theory. Because of its simple algorithm, good robustness and high reliability, it is widely used in industrial process control; however, PID control often needs to understand the controlled system The function characteristics of the system can be effectively controlled, and it takes too much time to fit those very complex and nonlinear systems.

Fuzzy control, which has become increasingly popular in recent years, is one of the most widely used intelligent temperature control technologies. It has good robustness and does not need to know the precise mathematical model of the control target and object. However, it is easy to cause steady-state errors due to rough control rules; therefore, it is difficult to achieve satisfactory results by using a simple fuzzy control method for the temperature of the semiconductor pulsed laser seed source.

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art, to provide a pulse laser seed source temperature control system and its control method, through the combination of fuzzy operation and PID control temperature control system to achieve an economical and effective Moreover, the stable pulse laser seed source temperature control scheme can realize rapid temperature change control with low power consumption; the temperature sensor is used to feed back the temperature signal, and the fuzzy operation is used to realize online reasoning, so as to realize the rapid temperature control of the pulse laser seed source. , Precise control, fast response speed of the temperature control system, which improves the stability of the temperature control system.

To achieve the above object, the technical solution adopted in the present invention is:

A temperature control system for a pulsed laser seed source, comprising a power supply module, a fuzzy PID controller and a laser diode for providing power to the entire device; the fuzzy PID controller includes a fuzzy controller and a PID controller, and the fuzzy PID controller A keyboard, a display module and a temperature sensor are connected to it, the fuzzy PID controller is connected to one end of the TEC drive circuit, the other end of the TEC drive circuit is connected to a TEC temperature control chip, and the TEC temperature control chip is pasted on one side of the heat conduction plate with silica gel, and the heat conduction plate The other side of the laser diode is pasted with silicone, and the sensor in the temperature sensor system is tightly connected to the heat conduction plate.

Preferably, the fuzzy controller includes a fuzzification interface, a rule base, a database, an inference engine and a defuzzification interface.

Preferably, the fuzzy PID controller calculates the deviation e and the deviation change rate ec according to the temperature information parameters of the laser diode measured by the temperature sensor and the corresponding preset parameters, and the fuzzy controller performs fuzzification and establishes a database And the rule base, fuzzy reasoning and defuzzification processing, get the correction value of the PID control parameters, and then control each execution device by the PID controller.

Preferably, the fuzzy PID controller is also connected to an alarm system.

Preferably, the heat conduction plate is aluminum plate or red copper.

Preferably, the TEC drive circuit includes a drive chip L298N, a power supply and several diodes, the 1st, 8th and 15th pins of the drive chip are grounded, the 4th and 9th pins are connected to the power supply, and the 5th and 7th pins are connected to the fuzzy PID controller, the 2nd pin is connected to the power module through the diode D1, while the 2nd pin is grounded through the diode D2, the 3rd pin is connected to the power module through the diode D4, and the 3rd pin is grounded through the diode D3, the 2nd and 3rd The pins are respectively connected to the positive pole and the negative pole of the TEC temperature control chip.

The present invention also provides a control method for a temperature control system of a pulsed laser seed source, including determining and preset pulsed laser seed source parameters, obtaining and comparing calculations, parameter correction and output control, and the specific steps are as follows:

S1. Determine and preset pulse laser seed source parameters: preset the determined temperature parameters to be controlled in the fuzzy PID controller through the keyboard;

S2. Obtain and compare and calculate: the temperature information parameter of the laser diode is measured by the temperature sensor, and then compared with the corresponding preset temperature parameter to be controlled to obtain the deviation e and the deviation change rate ec;

S3. Parameter correction and output control: Fuzzify the deviation e and deviation change rate ec as the input of the fuzzy controller, and establish a rule base and database based on a large amount of empirical data, and then obtain the PID temperature control parameters through fuzzy reasoning and defuzzification The correction value is input to the PID controller, and then the PID controller controls the work of each execution device; the execution device includes a TEC drive circuit and a TEC temperature control chip.

Preferably, a verification step is also included; the temperature sensor monitors the temperature information parameters of the laser diode in real time, and when the measured temperature information parameters of the laser diode are not equal to the preset parameters, the above steps are repeated.

Preferably, the control mathematical model is established through the control algorithm, and the PID controller is implanted; the control data of each period of the PID controller is obtained according to the experimental verification to adjust the control mathematical model; the control mathematical model can match the corresponding PID controller according to the preset temperature parameters. Control instructions for each period of time.

Compared with prior art, the beneficial effect of the present invention is:

(1) The pulsed laser seed source of the present invention adopts a temperature control system combining fuzzy operation and PID control to realize an economical, effective and stable temperature control scheme, which can realize the temperature of the pulsed laser seed source under lower power consumption. Change control, so as to ensure the stable output of pulse laser seed source power, high control accuracy, and greatly improved efficiency, and the control system can realize data communication, data processing and system control processing functions, high degree of automation, fast speed, high measurement efficiency, and error Small and easy to operate.

(2) The present invention realizes the temperature control function of the pulsed laser seed source through a digital circuit, which greatly reduces the complexity of the temperature control device. Since the pulsed laser seed source is very sensitive to temperature changes, the temperature control accuracy is relatively strict. Traditional The PID control technology cannot meet the high-precision control requirements. The present invention adopts the temperature control method combining fuzzy operation and PID control. When the temperature error is large, the fuzzy algorithm control is used to quickly reduce the temperature; when the temperature error Entering the fine-tuning stage, the PID control algorithm is adopted to reduce the overshoot of the system and realize the stable control of the temperature control system. The method of the present invention has the advantages of fast response speed, small overshoot and high stability.

(3) The temperature sensor is used to feed back the temperature signal, and the fuzzy operation is used to realize online reasoning, so as to realize the rapid and precise control of the temperature of the temperature control box. The response speed of the temperature control system is fast, and the stability of the temperature control system is improved.

Description of drawings

Fig. 1 is the system connection block diagram of the temperature control system of a kind of pulsed laser seed source of the present invention;

Fig. 2 is a schematic diagram of a TEC driving circuit in the present invention;

Fig. 3 is the schematic diagram of temperature sensor system in the present invention;

Fig. 4 is the working principle figure of fuzzy PID controller of the present invention;

Fig. 5 is the control system algorithm program flowchart of fuzzy PID controller of the present invention;

Fig. 6 is the fuzzy control rule table in the embodiment of the present invention;

Fig. 7 is the control algorithm flowchart of fuzzy controller in the embodiment;

Fig. 8 is the control algorithm flowchart of PID controller in the embodiment;

Fig. 9 is a graph of temperature control data obtained in the embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail in conjunction with the following examples; it should be understood that the specific examples described here are only used to explain the present invention and are not intended to limit the present invention ; Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

The present invention will be described in further detail below through specific implementation examples and in conjunction with the accompanying drawings.

Example 1

As shown in Figure 1, a temperature control system for a pulsed laser seed source includes a power module, a fuzzy PID controller, a TEC drive circuit, a TEC temperature control chip, a laser diode, a heat conduction plate, a temperature sensor, a display module, a keyboard control and An alarm module, the fuzzy PID controller includes a fuzzy controller and a PID controller, the fuzzy PID controller is connected with a TEC drive circuit, a temperature sensor system, a display module, a keyboard control and an alarm module, and one end of the TEC drive circuit is connected with a fuzzy The other end of the PID controller is connected to the TEC temperature control chip. The TEC temperature control chip is pasted on one side of the heat conduction plate with silica gel, and the laser diode is pasted on the other side of the heat conduction plate. The sensor in the temperature sensor is closely connected with the heat conduction plate. The other end of the temperature sensor Connect the fuzzy PID controller, and the power module supplies power for the whole system.

Specifically, the fuzzy controller includes a fuzzy interface, a rule base, a database, an inference engine and a defuzzification interface.

During the temperature control process of the pulsed laser seed source, the fuzzy PID controller calculates the deviation e and the deviation change rate ec according to the temperature information parameters of the laser diode measured by the temperature sensor and the corresponding preset parameters, and the fuzzy control Fuzzification, establishment of database and rule base, fuzzy reasoning and defuzzification processing, to obtain the correction value of PID control parameters, and then the PID controller controls each execution device; the execution device includes TEC drive circuit, TEC temperature control chip .

Among them, the power module uses Lvyang YB1732A DC regulated power supply, the TEC temperature control chip uses semiconductor cooling chip TEC1-12706, and the heat conduction plate uses aluminum plate.

Specifically, as shown in Figure 2, the TEC drive circuit includes a drive chip L298N and 4 diodes. L298N is a product of SGS (SGS Standard Technology Service Co., Ltd.), a 15-pin Multiwatt package, which contains 4-channel logic drive The circuit contains two H-bridge high-voltage, high-current dual full-bridge drivers, which receive standard TTL logic level signals and can drive motors below 46V and 2A. The pins 1, 8 and 15 of the driver chip L298N are grounded, and the Pins 4 and 9 are connected to the power supply, pins 5 and 7 are connected to the fuzzy PID controller, pin 2 is connected to the power supply through diode D1, and pin 2 is grounded through diode D2, and pin 3 is connected to the power supply through diode D4. At the same time, the third pin is grounded through the diode D3, and the second and third pins are respectively connected to the anode and cathode of the TEC temperature control chip.

As shown in Figure 3, the temperature sensor includes a temperature sensor DS18B20, a power supply and a resistor R1 (10K ohms). The DS18B20 digital temperature sensor provides 9-12 digits of Celsius temperature measurement and has a programmable high and low level trigger that does not disappear due to power supply And change the alarm function, its temperature measurement range is -55 ~ +125 ℃, the first pin of the temperature sensor DS18B20 is grounded, the second pin is connected to the fuzzy PID controller, the third pin is connected to the power supply, the second pin Connect to pin 3 through resistor R1.

A control method based on the above-mentioned temperature control system of a pulsed laser seed source, including determining and preset parameters of the pulsed laser seed source, obtaining and comparing calculations, parameter correction and output control, the specific steps are as follows:

S1. Determine and preset pulse laser seed source parameters: preset the determined temperature parameters to be controlled in the fuzzy PID controller through the keyboard;

S2. Obtain and compare and calculate: the temperature information parameter of the laser diode is measured by the temperature sensor, and then compared with the corresponding preset temperature parameter to be controlled to obtain the deviation e and the deviation change rate ec;

S3. Parameter correction and output control: Fuzzify the deviation e and deviation change rate ec as the input of the fuzzy controller, and establish a rule base and database based on a large amount of empirical data, and then obtain the PID temperature control parameters through fuzzy reasoning and defuzzification The correction value is input to the PID controller, and then the PID controller controls the work of each execution device; the execution device includes a TEC drive circuit and a TEC temperature control chip.

S4. Calibration step: the temperature sensor monitors the temperature information parameters of the laser diode in real time, and when the measured temperature information parameters of the laser diode are not equal to the preset pulse laser seed source temperature parameters, repeat the above steps.

On the basis of the above, the control method of the temperature control system of the pulsed laser seed source also includes establishing a control mathematical model through a control algorithm, and implanting a PID controller; obtaining the control data adjustment control of each period of the PID controller according to experimental verification Mathematical model; the control mathematical model can match the corresponding control instructions for each period of time for the PID controller according to the preset temperature parameters.

Figure 4 shows the working principle diagram of the fuzzy PID controller. It forms a compound fuzzy PID controller by switching a single fuzzy controller and a single PID controller. The given parameter of the system in the figure is the temperature setting value r, the controlled parameter of the system is the temperature measurement value y(t), and the fuzzy PID controller decides which control algorithm to use according to the error e(t): when the error is in a large range (such as 10~100 % maximum temperature difference), use a fuzzy controller to improve the response speed of the system; when the error is within a small range (corresponding to 0~10% maximum temperature difference), use a PID controller to eliminate the steady-state error of the system. The switching value of the two acts as a switch, which is realized by software and is called "switching switch e ₀ ". In the start-up phase, that is, e(t)>e ₀ , the switching value makes the system start quickly under the action of the fuzzy controller ; Enter the fine-tuning stage, that is, e(t) < e ₀ , the transfer switch enables the system to eliminate errors under the action of the PID controller, so that a single fuzzy controller and a single PID controller can form a compound fuzzy PID controller, In this embodiment, e ₀ is taken as 10% of the maximum temperature difference, that is, 20×10%=2.

The control system algorithm program of the fuzzy PID controller is the interrupt response program of the system to the timer T ₀ , the main task is to select the fuzzy control algorithm and the PID control algorithm according to the temperature difference value e(k) obtained by the calculation process, the flow chart As shown in FIG. 5 , the timer T ₀ determines the temperature sampling frequency, and e ₀ is the switching threshold between fuzzy control and PID control. In this embodiment, e ₀ =2.

In the present invention, the fuzzy controller takes 16 MC9S12DG128 single-chip microcomputers of Freescal Company as the core, and the MC9S12DG128 single-chip microcomputers are internally integrated with 8-way 16-bit A/D converters and 8-way independent PWM controllers, which can effectively simplify the hardware of the system The structure is easy to expand, and it supports fuzzy instructions, which can easily implement fuzzy operation programs. The fuzzy controller is composed of two inputs and one output variable. The input variables are the temperature deviation e and the deviation change rate ec respectively, and the value of the deviation e is NB, NS, O, PS, PB, the value of the deviation change rate ec is NB, NS, O, PS, PB, the output variable is the output weight U of the PID controller, and its value is O, PS, PM, PB , the fuzzy rule table of PID output weight U is shown in Figure 6.

As shown in Figure 7, the control algorithm in the fuzzy controller is implemented by a program, which includes two parts: one is to calculate the fuzzy control look-up table offline, and store the fuzzy control table in the program memory of the fuzzy controller microcontroller; During the control process, the fuzzy controller directly communicates with the value stored in the fuzzy controller microcontroller according to the deviation value e(k) and the temperature difference change rate ec(k) at a certain moment after fuzzy reasoning. The data in the table is compared to find out the output, and then it is used to adjust the temperature of the pulse laser seed source after being refined.

The flow chart of the PID controller subroutine is shown in Figure 8. When the temperature deviation e(k) is less than 2°C, the system switches from the fuzzy control algorithm to the PID control algorithm to eliminate the static error, where A, B, and C are PID The three control parameters of the controller are obtained through SIMULINK simulation and stored in the on-chip ROM of the PID controller microcontroller; P1.1 controls the driving direction of the TEC drive circuit, and △u(k) represents the kth temperature sampling The temperature variation of the TEC drive circuit calculated at any time.

As shown in Figure 9, when the temperature of the pulsed laser seed source was 27°C at the beginning, and the set temperature was 14°C, the temperature control system of the present invention was used to control the temperature of the pulsed laser seed source, and the temperature of the pulsed laser seed source was the same as The time relationship is shown in Figure 9. It can be seen from Figure 9 that the adjustment time for controlling the temperature of the pulsed laser seed source is about 30s, and the system has no overshoot; the error of the system is ± 0.05°C.

The above is only an illustrative embodiment of the present invention, and is not intended to limit the present invention in any form and in essence. Several improvements and supplements should also be regarded as the scope of protection of the present invention; those who are familiar with this profession can use the technical content disclosed above to make some changes, modifications and evolutions without departing from the spirit and scope of the present invention. The equivalent changes are all equivalent embodiments of the present invention; at the same time, all changes, modifications and evolutions of any equivalent changes made to the above-mentioned embodiments according to the substantive technology of the present invention still belong to the protection scope of the present invention.

Claims (9)

1. a kind of temperature control system of pulsed laser seed source, it is characterized in that, comprise the power supply module, fuzzy PID controller and laser diode that provide power for whole device; Described fuzzy PID controller comprises fuzzy controller and PID controller, A keyboard, a display module, and a temperature sensor are connected to the fuzzy PID controller, one end of the fuzzy PID controller is connected to the TEC driving circuit, the other end of the TEC driving circuit is connected to a TEC temperature control chip, and the TEC temperature control chip is pasted on a heat conducting On one side of the board, the other side of the heat conduction plate is glued with a laser diode, and the sensor in the temperature sensor system is tightly connected to the heat conduction plate. 2. The temperature control system of a pulsed laser seed source according to claim 1, wherein the fuzzy controller includes a fuzzification interface, a rule base, a database, an inference engine, and a defuzzification interface. 3. the temperature control system of a kind of pulsed laser seed source according to claim 1, is characterized in that, described fuzzy PID controller compares and calculates according to the temperature information parameter of the laser diode that temperature sensor records and corresponding preset parameter Obtain the deviation e and the deviation change rate ec, and perform fuzzification by the fuzzy controller, establish a database and rule base, fuzzy reasoning and defuzzification processing, obtain the correction value of the PID control parameters, and then control each execution device by the PID controller . 4. The temperature control system of a pulsed laser seed source according to claim 1, wherein the fuzzy PID controller is also connected to an alarm system. 5. A temperature control system for a pulsed laser seed source according to claim 1, wherein the heat conducting plate is an aluminum plate or copper. 6. The temperature control system of a pulsed laser seed source according to claim 1, wherein the TEC driving circuit comprises a driving chip L298N, a power supply and several diodes, and the first, eighth and 15th diodes of the driving chip The pin is grounded, the 4th and 9th pins are connected to the power supply, the 5th and 7th pins are connected to the fuzzy PID controller, the 2nd pin is connected to the power module through the diode D1, and the 2nd pin is grounded through the diode D2, and the 3rd pin The power module is connected through the diode D4, while the third pin is grounded through the diode D3, and the second and third pins are respectively connected to the anode and cathode of the TEC temperature control chip. 7. A control method for a temperature control system of a pulsed laser seed source, characterized in that it includes determining and preset pulsed laser seed source parameters, obtaining and comparing calculations and parameter corrections and output control, the specific steps are as follows: S1. Determine and preset pulse laser seed source parameters: preset the determined temperature parameters to be controlled in the fuzzy PID controller through the keyboard; S2. Obtain and compare and calculate: the temperature information parameter of the laser diode is measured by the temperature sensor, and then compared with the corresponding preset temperature parameter to be controlled to obtain the deviation e and the deviation change rate ec; S3. Parameter correction and output control: Fuzzify the deviation e and deviation change rate ec as the input of the fuzzy controller, and establish a rule base and database based on a large amount of empirical data, and then obtain the PID temperature control parameters through fuzzy reasoning and defuzzification The correction value is input to the PID controller, and then the PID controller controls the work of each execution device; the execution device includes a TEC drive circuit and a TEC temperature control chip. 8. the control method of the temperature control system of a kind of pulsed laser seed source according to claim 7, is characterized in that, also comprises verification step; Temperature sensor monitors the temperature information parameter of laser diode in real time, when measured laser diode When the temperature information parameter is not equal to the preset parameter, repeat the above steps. 9. the control method of the temperature control system of a kind of pulsed laser seed source according to claim 7 is characterized in that, establishes control mathematical model by control algorithm, and implants PID controller; The control data of the time period adjusts the control mathematical model; the control mathematical model can match the corresponding control instructions for each time period for the PID controller according to the preset temperature parameters.