High-precision high-power Raman light source laser temperature control system based on MFAC

Abstract

The invention discloses an MFAC-based high-precision high-power Raman light source laser temperature control system, which comprises a main control module, a constant current driving circuit and a constant temperature control module which are electrically connected with a Raman light source laser, and is characterized in that the Raman light source laser comprises a pumping source, a TEC and a thermistor which are located in a shell. According to the high-precision and high-power Raman light source laser temperature control system based on the MFAC, the resistance value of the thermistor is collected, the corresponding actual temperature is obtained, the actual temperature is compared with the expected temperature, the PWM duty ratio is calculated, and the corresponding PWM wave signal is used as the input of the TEC driving circuit, so that the refrigeration work or non-work of the TEC is driven; therefore, the working temperature of the Raman light source laser in different environments is kept stable, and the temperature control of the Raman light source laser is further realized. And the MFAC algorithm is adopted, so that the requirements of high precision and low time lag of Raman light source laser temperature control can be better met.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature control, and in particular relates to a high-precision and high-power Raman light source laser temperature control system based on MFAC. Background Art

[0002] Laser light source is an important component of Raman spectrometer. Raman light source laser has become a hot topic in current laser technology research and the first choice for Raman spectrometer laser light source due to its advantages such as good beam quality, high efficiency, compact structure, stability and ease of use. Raman laser output module with Raman light source laser as the main component is facing changes such as increased laser power demand and miniaturization of laser module space. The heat flux density of the devices in the module increases, the heat dissipation effect is poor, and the temperature soars sharply, causing the resonant cavity to expand and contract, and the length changes, which causes the laser output wavelength to shift, seriously affecting spectral imaging. Therefore, in the use of high-power lasers, in order to ensure that the laser can work stably, an efficient temperature control system is required to accurately control the constant temperature inside the laser.

[0003] PID is the most widely used model-free control algorithm. Most systems that are difficult to implement through modeling can achieve stable operation under PID control, but PID has poor control effect on nonlinear and time-varying systems. The Raman light source laser temperature control system of this project is a nonlinear and time-varying system with multiple interferences, strong coupling, multiple environments, limited chip computing power, but at the same time, it has high-precision and low-time-delay requirements. When PID is applied to this system, there are problems such as low temperature control accuracy and high time lag, which are not good control effects. Summary of the invention

[0004] The purpose of the present invention is to solve the problems raised in the background technology and to propose a high-precision and high-power Raman light source laser temperature control system based on MFAC.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] The present invention proposes a high-precision and high-power Raman light source laser temperature control system based on MFAC, wherein the temperature control system comprises a main control module, a constant current drive circuit and a constant temperature control module which are electrically connected to the Raman light source laser respectively, wherein:

[0007] The Raman light source laser comprises a pump source, a TEC and a thermistor located in a housing;

[0008] The constant temperature control module includes a TEC drive circuit and an A / D conversion acquisition circuit. The TEC drive circuit is used to receive a pair of complementary PWM signals input by the main control module, and form a current of corresponding magnitude and direction to input to the TEC, and the TEC performs cooling work or does not work according to the magnitude and direction of the received current;

[0009] The A / D conversion acquisition circuit is used to collect the resistance value of the thermistor in real time and send the resistance value to the main control module;

[0010] The main control module includes a temperature calculation unit, a temperature stability judgment unit, a PWM calculation unit and a GPIO controller. The temperature calculation unit is used to receive the resistance value sent by the A / D conversion acquisition circuit, and obtain the actual temperature of the thermistor at a corresponding moment in combination with the corresponding relationship between the resistance value of the thermistor and the actual temperature of the thermistor, and send the actual temperature to the temperature stability judgment unit and the PWM calculation unit respectively, and the actual temperature is used as the operating temperature of the Raman light source laser at the corresponding moment;

[0011] The temperature stability judgment unit is used to compare the received actual temperature with the expected temperature to judge whether the actual temperature is equal to the expected temperature, and when the actual temperature is equal and remains stable, the temperature of the Raman light source laser is controlled;

[0012] The PWM calculation unit is used to receive the actual temperature sent by the temperature calculation unit, and calculate the PWM duty cycle according to the expected temperature and the actual temperature using the MFAC algorithm, and output a pair of complementary PWM signals with corresponding duty cycles to the input end of the TEC drive circuit according to the PWM duty cycle;

[0013] The GPIO controller is used to generate a control signal to control the constant current drive circuit to drive the pump source on or off.

[0014] Preferably, the A / D conversion acquisition circuit includes an ADC chip, a reference resistor REF, a first lead resistor RL1, a second lead resistor RL2, a third lead resistor RL3, a first capacitor C1, a second capacitor C2 and an inductor L, the fourth pin and the fifth pin of the ADC chip are respectively connected to one end of the first lead resistor RL1, the other end of the first lead resistor RL1 is connected to one end of the thermistor, the other end of the thermistor is respectively connected to one end of the second lead resistor RL2 and one end of the third lead resistor RL3, the other end of the second lead resistor RL2 is respectively connected to the sixth pin and the eleventh pin of the ADC chip, and the third lead resistor RL3 is connected to the sixth pin and the eleventh pin of the ADC chip. The other end of the lead resistor RL3 is respectively connected to the ninth pin of the ADC chip and one end of the reference resistor REF, the other end of the reference resistor REF is respectively connected to the tenth pin and the twelfth pin of the ADC chip, as well as to one plate of the first capacitor C1 and one plate of the second capacitor C2, the fourteenth pin of the ADC chip is respectively connected to one end of the inductor L, the other plate of the first capacitor C1 and the other plate of the second capacitor C2, the thirteenth pin of the ADC chip is connected to the other end of the inductor L, and the first pin, the third pin, the sixteenth pin, the fifteenth pin and the fourteenth pin of the ADC chip are all connected to the power supply voltage.

[0015] Preferably, when the A / D conversion acquisition circuit acquires the resistance value of the thermistor, the three-wire measurement method is first used to measure the resistance value of the thermistor, and the formula is as follows:

[0016] ;

[0017] And because,

[0018] ;

[0019] get:

[0020] ;

[0021] in, Indicates the resistance of the thermistor. Indicates the resistance value of the reference resistor, represents the voltage across the thermistor, represents the voltage across the reference resistor, Indicates gain, the value is 1, Indicates the number of bits of the ADC chip, Indicates the value collected from the ADC chip data register.

[0022] Preferably, the TEC driving circuit adopts an H-bridge circuit, including a first MOS tube Q1, a second MOS tube Q2, a third MOS tube Q3, a fourth MOS tube Q4, a fifth MOS tube Q5, a sixth MOS tube Q6, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14;

[0023] One end of the second resistor R2 and one end of the fourth resistor R4 serve as input ends of the TEC driving circuit, and are sequentially connected to a PWM signal + and another complementary PWM signal - input by the PWM calculation unit, the other end of the second resistor R2 is respectively connected to one end of the third resistor R3 and the gate of the first MOS tube Q1, the other end of the third resistor R3 and the source of the first MOS tube Q1 are both grounded, the drain of the first MOS tube Q1 is respectively connected to one end of the first resistor R1 and the gate of the second MOS tube Q2, the other end of the first resistor R1 is respectively connected to the source of the second MOS tube Q2 and the One plate of the three capacitors C3 is connected and connected to the power supply voltage, the drain of the second MOS tube Q2 is respectively connected to the drain of the third MOS tube Q3, one end of the sixth resistor R6, one plate of the fourth capacitor C4 and the positive electrode of the TEC, the other end of the sixth resistor R6 is connected to the other plate of the third capacitor C3, the gate of the third MOS tube Q3 is respectively connected to the other end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fifth resistor R5, the source of the third MOS tube Q3 and one end of the seventh resistor R7 are all grounded, and the other end of the seventh resistor R7 is connected to the other plate of the fourth capacitor C4;

[0024] One end of the eleventh resistor R11 and one end of the ninth resistor R9 serve as input ends of the TEC driving circuit, and are connected in sequence to a PWM signal + and another complementary PWM signal - input by the PWM calculation unit. The other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the gate of the fourth MOS tube Q4 respectively. Both ends of the tenth resistor R10 and the source of the fourth MOS tube Q4 are grounded. The drain of the fourth MOS tube Q4 is connected to one end of the eighth resistor R8 and the gate of the fifth MOS tube Q5 respectively. The other end of the eighth resistor R8 is connected to the source of the fifth MOS tube Q5 and the fifth capacitor C 5 is connected to one electrode plate of the fifth capacitor C5 and is connected to the power supply voltage, the other electrode plate of the fifth capacitor C5 is connected to one end of the thirteenth resistor R13, the drain of the fifth MOS tube Q5 is respectively connected to the other end of the thirteenth resistor R13, the drain of the sixth MOS tube Q6, one electrode plate of the sixth capacitor C6 and the negative electrode of TEC, the gate of the sixth MOS tube Q6 is respectively connected to one end of the twelfth resistor R12 and the other end of the eleventh resistor R11, the other end of the twelfth resistor R12, the source of the sixth MOS tube Q6 and one end of the fourteenth resistor are all grounded, and the other end of the fourteenth resistor is connected to the other electrode plate of the sixth capacitor C6.

[0025] Preferably, the first MOS transistor Q1 , the third MOS transistor Q3 , the fourth MOS transistor Q4 and the sixth MOS transistor Q6 are all NMOS transistors, and the second MOS transistor Q2 and the fifth MOS transistor Q5 are PMOS transistors.

[0026] Preferably, the PWM calculation unit adopts the MFAC algorithm to calculate the PWM duty cycle according to the expected temperature and the actual temperature. The formula is as follows:

[0027] ;

[0028] in,

[0029] ;

[0030] in, express The PWM duty cycle at the moment, express The PWM duty cycle at the moment, express The PWM duty cycle at the moment, Represents thermistor The actual temperature at the moment, Represents thermistor The actual temperature at the moment, , , and Both represent weight coefficients, Represents thermistor The expected temperature at the time, and the expected temperature at different times remains consistent, express The intermediate parameters of the moment, express Intermediate parameters of time.

[0031] Preferably, the temperature control system further comprises a heat sink disposed on the housing of the Raman light source laser.

[0032] Preferably, the temperature control system further comprises a host computer, and the temperature stability judgment unit uploads the real-time actual temperature to the host computer for display.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The high-precision and high-power Raman light source laser temperature control system based on MFAC collects the resistance value of the thermistor and obtains the corresponding actual temperature, compares the actual temperature with the expected temperature, calculates the PWM duty cycle and uses the corresponding PWM wave signal as the input of the TEC drive circuit to drive the TEC to work or not work, so that the working temperature of the Raman light source laser remains stable in different environments, thereby realizing the temperature control of the Raman light source laser; and the use of the MFAC algorithm can better meet the requirements of high precision and low time lag of Raman light source laser temperature control. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a module block diagram of the high-precision and high-power Raman light source laser temperature control system based on MFAC of the present invention;

[0036] Figure 2 is a circuit diagram of a TEC driving circuit of the present invention;

[0037] Figure 3 A circuit diagram of the A / D conversion acquisition circuit of the present invention;

[0038] Figure 4 is a block diagram of the MFAC algorithm in the PWM calculation unit;

[0039] Figure 5 This is a working flow chart of the high-precision and high-power Raman light source laser temperature control system based on MFAC of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0041] like Figure 1-Figure 5As shown, the present application provides a high-precision and high-power Raman light source laser temperature control system based on MFAC, wherein:

[0042] like Figure 1 As shown, the temperature control system includes a main control module, a constant current drive circuit and a constant temperature control module which are electrically connected to the Raman light source laser respectively, wherein:

[0043] A Raman light source laser comprises a pump source, a TEC and a thermistor located in a housing; wherein the working pump source of the Raman light source laser

[0044] The constant temperature control module includes a TEC drive circuit and an A / D conversion acquisition circuit. The TEC drive circuit is used to receive a complementary PWM signal input from the main control module and form a current of corresponding magnitude and direction to input to the TEC. The TEC performs cooling work or does not work according to the magnitude and direction of the received current.

[0045] The A / D conversion acquisition circuit is used to collect the resistance value of the thermistor in real time and send the resistance value to the main control module;

[0046] The main control module includes a temperature calculation unit, a temperature stability judgment unit, a PWM calculation unit and a GPIO controller. The temperature calculation unit is used to receive the resistance value sent by the A / D conversion acquisition circuit, and obtain the actual temperature of the thermistor at a corresponding moment in combination with the corresponding relationship between the resistance value of the thermistor and the actual temperature of the thermistor, and send the actual temperature to the temperature stability judgment unit and the PWM calculation unit respectively, and the actual temperature is used as the operating temperature of the Raman light source laser at the corresponding moment;

[0047] A temperature stability judgment unit is used to compare the received actual temperature with the expected temperature to judge whether the actual temperature is equal to the expected temperature, and when the actual temperature is equal and remains stable, the temperature of the Raman light source laser is controlled;

[0048] The PWM calculation unit is used to receive the actual temperature sent by the temperature calculation unit, and calculate the PWM duty cycle according to the expected temperature and the actual temperature using the MFAC algorithm, and output a pair of complementary PWM signals with corresponding duty cycles to the input end of the TEC drive circuit according to the PWM duty cycle;

[0049] The GPIO controller is used to generate a control signal to control the constant current drive circuit to drive the pump source on or off.

[0050] It should be noted that the Raman light source laser is a semiconductor fiber laser. MFAC (Model Free Adaptive Control) is a model-free control algorithm that uses the newly introduced pseudo-gradient vector and pseudo-order concepts to replace the general discrete-time nonlinear system with a dynamic linear time-varying model to achieve MFAC of the nonlinear system. It has the advantage of handling strong nonlinear and time-varying system control problems. Compared with the PID algorithm, it has better control effects on the nonlinear and time-varying Raman light source laser temperature control system, and can better meet the requirements of high-precision and low-time lag in temperature control.

[0051] The structure of the Raman light source laser belongs to the prior art and will not be described in detail. The GPIO controller drives the pump source on or off by controlling the constant current drive circuit (wherein the constant current drive circuit is composed of the high-voltage constant current laser controller ATLS2A212 of Anshan Hengguang Technology and the peripheral circuit in the prior art, wherein the peripheral circuit can be designed according to the conventional method, and the specific design belongs to the prior art and will not be described in this application), thereby turning the Raman light source laser on or off. The Raman light source laser will generate heat during operation. In this embodiment, the thermistor ( Figure 3 The temperature corresponding to the resistance value of (represented by NTC in the figure) is used as the working temperature of the Raman light source laser, and the Raman light source laser is cooled by TEC (Thermo Electric Cooler) in Raman light source laser refers to a semiconductor cooler, also known as a thermoelectric cooler), so that the actual working temperature of the Raman light source laser is kept close to the expected temperature (where the expected temperature is a pre-set temperature, which is not limited and can be set according to actual needs);

[0052] The temperature controller system also includes a power module, which provides power to each unit or device in the main control module, as well as to the TEC drive circuit and A / D conversion acquisition circuit in the constant temperature control module, and to each component in the Raman light source laser. The power module is connected to the constant current drive circuit, and the GPIO controller controls the constant current drive circuit to power on or off the pump source, thereby realizing the opening or closing of the pump source.

[0053] The temperature control system also includes a host computer, and the temperature stability judgment unit uploads the real-time actual temperature to the host computer for display.

[0054] like Figure 5 As shown, the process of temperature control of the Raman light source laser is as follows (first power on the entire temperature control system):

[0055] Step 1, the A / D conversion acquisition circuit acquires the resistance value of the thermistor in real time, and sends the resistance value to the temperature calculation unit, and then executes step 2.1;

[0056] Among them, Figure 3 As shown, the A / D conversion acquisition circuit includes an ADC chip, a reference resistor REF, a first lead resistor RL1, a second lead resistor RL2, a third lead resistor RL3, a first capacitor C1, a second capacitor C2 and an inductor L, the fourth pin and the fifth pin of the ADC chip are respectively connected to one end of the first lead resistor RL1, the other end of the first lead resistor RL1 is connected to one end of the thermistor, the other end of the thermistor is respectively connected to one end of the second lead resistor RL2 and one end of the third lead resistor RL3, the other end of the second lead resistor RL2 is respectively connected to the sixth pin and the eleventh pin of the ADC chip, the other end of the third lead resistor RL3 is respectively connected to the ninth pin of the ADC chip and the reference pin One end of the reference resistor REF is connected, the other end of the reference resistor REF is respectively connected to the tenth pin and the twelfth pin of the ADC chip, and is respectively connected to one plate of the first capacitor C1 and one plate of the second capacitor C2, the fourteenth pin of the ADC chip is respectively connected to one end of the inductor L, the other plate of the first capacitor C1 and the other plate of the second capacitor C2, the thirteenth pin of the ADC chip is connected to the other end of the inductor L, and the first pin, the third pin, the sixteenth pin, the fifteenth pin and the fourteenth pin of the ADC chip are all connected to the power supply voltage (in this embodiment, the power supply voltage is 3.3V, which is provided by the power supply module, and the power supply module can be powered by boosting or depressurizing, such as Figure 3 The power supply voltage is represented by 3V3).

[0057] In this embodiment, the ADC chip model is AD7792, and the SPI communication protocol is adopted with the main control module (specifically, the temperature stability judgment unit of the main control module, the model of the main control module is the STM32 chip). The resistance analog signal of the thermistor is converted into a digital signal through the A / D conversion acquisition circuit and transmitted to the temperature stability judgment unit. Its first pin is SCLK, the third pin is CS*, the fourth pin is IOUT1, the fifth pin is AIN1+, the sixth pin is AIN1-, the eighth pin is AIN2-, the ninth pin is REFIN+, the tenth pin is REFIN-, the eleventh pin is IOUT2, the twelfth pin is GND, the thirteenth pin is AVDD, and the The fourteenth pin is DVDD, the fifteenth pin is DOUT / DRY, and the sixteenth pin is DIN. The reference resistor is a precision resistor with low temperature drift. The fourth pin constant current source 1 (i.e., IOUT1) and the eleventh pin constant current source 2 (i.e., IOUT2) flow out currents of the same magnitude. The current I of the constant current source 1 flows through the thermistor NTC and merges with the current I of the constant current source 2 to form 2I that flows through the reference resistor; the fifth pin and the sixth pin are connected to both ends of the thermistor NTC to measure the voltage value of the NTC; the ninth pin and the tenth pin are connected to both ends of the reference resistor to measure the voltage value of the reference resistor; the above is an ideal state measurement, but there is lead resistance, and RL1, RL2, and RL3 are simulated as the resistance of each lead part.

[0058] Among them, when the A / D conversion acquisition circuit acquires the resistance value of the thermistor, the three-wire measurement method is first used to measure the resistance value of the thermistor, and the resistance value of the thermistor measured by the three-wire measurement method conforms to the following formula:

[0059] ;

[0060] And because,

[0061] ;

[0062] get:

[0063] ;

[0064] in, Indicates the resistance of the thermistor. Indicates the resistance value of the reference resistor (the reference resistor is a 51k low temperature drift precision resistor). represents the voltage across the thermistor, represents the voltage across the reference resistor, Indicates gain, the value is 1, Indicates the number of bits of the ADC chip (the ADC chip in this embodiment is 16 bits, that is, ), Represents the value collected from the ADC chip data register (the data register is a register inside the ADC chip, which belongs to the prior art and will not be described in detail).

[0065] Step 2.1, the temperature calculation unit combines the corresponding relationship between the resistance value of the thermistor and the actual temperature of the thermistor to obtain the actual temperature of the thermistor at the corresponding moment, and uses the actual temperature as the working temperature of the Raman light source laser at the corresponding moment; for thermistors of different models, different resistance values ​​are set during the production process, and there are temperatures corresponding to each resistance value. For example, a thermistor with a B value of 3950K and a resistance value of 10K, when its resistance is measured to be 12490Ω, according to the corresponding relationship between resistance value and temperature, the temperature at this time is 20°C, and then step 2.2 is executed.

[0066] Step 2.2: The temperature calculation unit sends the obtained real-time actual temperature to the PWM calculation unit, and then executes step 3. At the same time, the temperature calculation unit sends the obtained real-time actual temperature to the temperature stability judgment unit, and then executes step 2.3.

[0067] Step 2.3, the temperature stability judgment unit compares the actual temperature with the expected temperature to determine whether the actual temperature is equal to the expected temperature and stable (specifically, whether the actual temperature is close to the expected temperature, that is, whether the actual temperature is within a preset range within a specified time based on the expected temperature. For example, if the expected temperature is 25°C and the actual temperature remains at 25°C for 5 seconds, When the actual temperature is close to the expected temperature and is stable, the temperature of the Raman light source laser is controlled, and then the temperature stability judgment unit transmits a temperature stability signal to the upper computer. At this time, the Raman spectrometer starts to work and collects Raman spectra.

[0068] Step 3, the PWM calculation unit receives the actual temperature sent by the temperature calculation unit, and uses the MFAC algorithm to calculate the PWM duty cycle according to the expected temperature and the actual temperature, and outputs a pair of complementary and corresponding duty cycle PWM signals to the input end of the TEC drive circuit according to the PWM duty cycle.

[0069] Among them, Figure 4 As shown, the A / D conversion acquisition circuit and the temperature calculation unit are represented by the temperature acquisition circuit. Figure 4 A block diagram showing the MFAC algorithm in the PWM calculation unit. The PWM calculation unit uses the MFAC algorithm to calculate the PWM duty cycle based on the desired temperature and the actual temperature as follows:

[0070] ;

[0071] in,

[0072] ;

[0073] Among them, thermistor The actual temperature at a certain moment is related to the actual temperature and duty cycle at all previous moments, which can be expressed by a pseudo function as follows:

[0074] ;

[0075] in, express The PWM duty cycle at the moment, express The PWM duty cycle at the moment, express The PWM duty cycle at the moment, Represents thermistor The actual temperature at the moment, Represents thermistor The actual temperature at the moment, , , and Both represent weight coefficients, Indicates the thermistor collected The number of moments before the actual temperature at the moment, express The number of moments before the PWM duty cycle at moment, Represents thermistor The expected temperature at the time, and the expected temperature at different times remains consistent, express The intermediate parameters of the moment, express Intermediate parameters of time.

[0076] Then the PWM calculation unit outputs a pair of complementary and corresponding duty cycle PWM signals to the input end of the TEC driving circuit according to the PWM duty cycle (i.e., inputs a corresponding pair of complementary PWM waves to the input end of the TEC driving circuit according to the PWM duty cycle), and then executes step 4.

[0077] Step 4: The TEC driving circuit is used to receive a pair of complementary PWM signals input by the main control module, and form a current of corresponding magnitude and direction to be input to the TEC, and the TEC performs cooling work or does not work according to the magnitude and direction of the received current.

[0078] Among them, the TEC driving circuit adopts an H-bridge circuit, including a first MOS tube Q1, a second MOS tube Q2, a third MOS tube Q3, a fourth MOS tube Q4, a fifth MOS tube Q5, a sixth MOS tube Q6, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14.

[0079] One end of the second resistor R2 and one end of the fourth resistor R4 serve as input ends of the TEC driving circuit, and are connected in sequence to a PWM signal + and another complementary PWM signal - input by the PWM calculation unit. The other end of the second resistor R2 is connected to one end of the third resistor R3 and the gate of the first MOS transistor Q1 respectively. The other end of the third resistor R3 and the source of the first MOS transistor Q1 are both grounded. The drain of the first MOS transistor Q1 is connected to one end of the first resistor R1 and the gate of the second MOS transistor Q2 respectively. The other end of the first resistor R1 is connected to the source of the second MOS transistor Q2 and a plate of the third capacitor C3 respectively, and is connected to the power supply voltage (i.e., Figure 2 VCC in the figure represents the power supply voltage, which is provided by the power supply module), the drain of the second MOS tube Q2 is respectively connected to the drain of the third MOS tube Q3, one end of the sixth resistor R6, one plate of the fourth capacitor C4 and the positive electrode of TEC, the other end of the sixth resistor R6 is connected to the other plate of the third capacitor C3, the gate of the third MOS tube Q3 is respectively connected to the other end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fifth resistor R5, the source of the third MOS tube Q3 and one end of the seventh resistor R7 are all grounded, and the other end of the seventh resistor R7 is connected to the other plate of the fourth capacitor C4.

[0080] One end of the eleventh resistor R11 and one end of the ninth resistor R9 serve as input ends of the TEC driving circuit, and are connected in sequence to a PWM signal + and another complementary PWM signal - input by the PWM calculation unit. The other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the gate of the fourth MOS tube Q4, respectively. Both ends of the tenth resistor R10 and the source of the fourth MOS tube Q4 are grounded. The drain of the fourth MOS tube Q4 is connected to one end of the eighth resistor R8 and the gate of the fifth MOS tube Q5, respectively. The other end of the eighth resistor R8 is connected to the source of the fifth MOS tube Q5 and one plate of the fifth capacitor C5, and is connected to the power supply voltage (i.e., as shown in FIG. Figure 2VCC in the figure represents the power supply voltage, which is provided by the power supply module), the other electrode plate of the fifth capacitor C5 is connected to one end of the thirteenth resistor R13, the drain of the fifth MOS tube Q5 is respectively connected to the other end of the thirteenth resistor R13, the drain of the sixth MOS tube Q6, one electrode plate of the sixth capacitor C6 and the negative electrode of TEC, the gate of the sixth MOS tube Q6 is respectively connected to one end of the twelfth resistor R12 and the other end of the eleventh resistor R11, the other end of the twelfth resistor R12, the source of the sixth MOS tube Q6 and one end of the fourteenth resistor are all grounded, and the other end of the fourteenth resistor is connected to the other electrode plate of the sixth capacitor C6; wherein the power supply voltage of the TEC driving circuit in this embodiment is 7V.

[0081] The first MOS transistor Q1 , the third MOS transistor Q3 , the fourth MOS transistor Q4 and the sixth MOS transistor Q6 are all NMOS transistors, and the second MOS transistor Q2 and the fifth MOS transistor Q5 are PMOS transistors.

[0082] It should be noted that the TEC driving circuit in the present embodiment is improved from a bipolar H-bridge circuit, and is mainly composed of a second MOS transistor Q2, a third MOS transistor Q3, a fifth MOS transistor Q5 and a sixth MOS transistor Q6 in the bipolar H-bridge circuit, and a first MOS transistor Q1 and a fourth MOS transistor Q4 and their peripheral circuits for driving the second MOS transistor Q2 and the fifth MOS transistor Q5 in the bipolar H-bridge; a PWM wave signal corresponding to the PWM duty cycle is input to the input end of the TEC driving circuit, and the switch state of the MOS tube in the TEC driving circuit is changed to realize the control of the current direction and magnitude.

[0083] When the actual temperature is higher than the desired temperature and cooling is required, the PWM calculation unit inputs the corresponding complementary PWM to the input end of the TEC drive circuit according to the calculated PWM duty cycle. At this time, the PWM signal + is at a high level, and the complementary PWM signal - is at a low level. At this time: the gate of the first MOS transistor Q1 is at a high level, VG>VS (i.e., the gate voltage is higher than the source voltage), the first MOS transistor Q1 conducts, and then the gate of the second MOS transistor Q2 is approximately grounded, VG<VS (i.e., the gate voltage is lower than the source voltage), driving the second MOS transistor Q2 to conduct; the gate of the third MOS transistor Q3 is at a low level, VG≈VS (i.e., the gate voltage is close to the source voltage), the third MOS transistor Q3 is turned off; the gate of the fourth MOS transistor Q4 is at a low level, VG≈VS (i.e., the gate voltage is close to the source voltage), the fourth MOS transistor Q4 is turned off, and then the gate of the fifth MOS transistor Q5 is pulled up to input VCC, VG≈VS (i.e., the gate voltage is close to the source voltage), driving the fifth MOS transistor Q5 to turn off; the gate of the sixth MOS transistor Q6 is at a high level, VG>VS (i.e., the gate voltage is higher than the source voltage), the sixth MOS transistor Q6 conducts; according to the on and off states of the four MOS transistors (i.e., the second MOS transistor Q2, the third MOS transistor Q3, the fifth MOS transistor Q5, and the sixth MOS transistor Q6) of the bipolar H-bridge at this time, the TEC current on the bipolar H-bridge will conduct to form a loop. At this time, the current flows into the TEC+ terminal (i.e., the positive terminal), and the current flows out of the TEC- terminal (i.e., the negative terminal), and the TEC starts to cool and work to cool the Raman light source laser, thereby reducing the actual temperature corresponding to the resistance value of the thermistor, and then returning to step 1. The A / D conversion acquisition circuit continues to collect the resistance value of the thermistor at the next moment in real time to realize the closed-loop control of the temperature until the actual temperature approaches and remains stable with the desired temperature, then the temperature control of the Raman light source laser is realized.

[0084] To further improve the heat dissipation effect, the temperature control system further includes a heat dissipation block provided on the housing of the Raman light source laser. Among them, the heat dissipation block is attached to the surface of the housing of the Raman light source laser through silicone grease to improve the heat dissipation effect.

[0085] This MFAC-based high-precision and high-power Raman light source laser temperature control system collects the resistance value of the thermistor, obtains the corresponding actual temperature, compares the actual temperature with the desired temperature, calculates the PWM duty cycle, and uses the corresponding PWM wave signal as the input of the TEC drive circuit to drive the cooling work or non-work of the TEC, so that the working temperature of the Raman light source laser remains stable in different environments, thereby realizing the temperature control of the Raman light source laser; and the MFAC algorithm can better meet the requirements of high-precision and low-time-delay temperature control of the Raman light source laser.

[0086] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A high-precision and high-power Raman light source laser temperature control system based on MFAC, characterized in that: The temperature control system comprises a main control module, a constant current drive circuit and a constant temperature control module which are electrically connected to the Raman light source laser respectively, wherein: The Raman light source laser comprises a pump source, a TEC and a thermistor located in a housing; The constant temperature control module includes a TEC drive circuit and an A / D conversion acquisition circuit. The TEC drive circuit is used to receive a pair of complementary PWM signals input by the main control module, and form a current of corresponding magnitude and direction to input to the TEC, and the TEC performs cooling work or does not work according to the magnitude and direction of the received current; The A / D conversion acquisition circuit is used to collect the resistance value of the thermistor in real time and send the resistance value to the main control module; The main control module includes a temperature calculation unit, a temperature stability judgment unit, a PWM calculation unit and a GPIO controller. The temperature calculation unit is used to receive the resistance value sent by the A / D conversion acquisition circuit, and obtain the actual temperature of the thermistor at a corresponding moment in combination with the corresponding relationship between the resistance value of the thermistor and the actual temperature of the thermistor, and send the actual temperature to the temperature stability judgment unit and the PWM calculation unit respectively, and the actual temperature is used as the operating temperature of the Raman light source laser at the corresponding moment; The temperature stability judgment unit is used to compare the received actual temperature with the expected temperature to judge whether the actual temperature is equal to the expected temperature, and when the actual temperature is equal and remains stable, the temperature of the Raman light source laser is controlled; The PWM calculation unit is used to receive the actual temperature sent by the temperature calculation unit, and calculate the PWM duty cycle according to the expected temperature and the actual temperature using the MFAC algorithm, and output a pair of complementary PWM signals with corresponding duty cycles to the input end of the TEC drive circuit according to the PWM duty cycle; The GPIO controller is used to generate a control signal to control the constant current drive circuit to drive the pump source on or off.

2. The high-precision and high-power Raman light source laser temperature control system based on MFAC as claimed in claim 1, characterized in that: The A / D conversion acquisition circuit includes an ADC chip, a reference resistor REF, a first lead resistor RL1, a second lead resistor RL2, a third lead resistor RL3, a first capacitor C1, a second capacitor C2 and an inductor L. The fourth pin and the fifth pin of the ADC chip are respectively connected to one end of the first lead resistor RL1, the other end of the first lead resistor RL1 is connected to one end of the thermistor, the other end of the thermistor is respectively connected to one end of the second lead resistor RL2 and one end of the third lead resistor RL3, the other end of the second lead resistor RL2 is respectively connected to the sixth pin and the eleventh pin of the ADC chip, and the third lead resistor RL3 is connected to the ADC chip. The other end of the resistor RL3 is respectively connected to the ninth pin of the ADC chip and one end of the reference resistor REF, the other end of the reference resistor REF is respectively connected to the tenth pin and the twelfth pin of the ADC chip, and are respectively connected to one plate of the first capacitor C1 and one plate of the second capacitor C2, the fourteenth pin of the ADC chip is respectively connected to one end of the inductor L, the other plate of the first capacitor C1 and the other plate of the second capacitor C2, the thirteenth pin of the ADC chip is connected to the other end of the inductor L, and the first pin, the third pin, the sixteenth pin, the fifteenth pin and the fourteenth pin of the ADC chip are all connected to the power supply voltage.

3. The high-precision and high-power Raman light source laser temperature control system based on MFAC as claimed in claim 2, characterized in that: When the A / D conversion acquisition circuit acquires the resistance value of the thermistor, the three-wire measurement method is first used to measure the resistance value of the thermistor, and the formula is as follows: ； And because, ； get: ； in, Indicates the resistance of the thermistor. Indicates the resistance value of the reference resistor, represents the voltage across the thermistor, represents the voltage across the reference resistor, Indicates gain, the value is 1, Indicates the number of bits of the ADC chip, Indicates the value collected from the ADC chip data register.

4. The high-precision and high-power Raman light source laser temperature control system based on MFAC as claimed in claim 1, characterized in that: The TEC driving circuit adopts an H-bridge circuit, including a first MOS tube Q1, a second MOS tube Q2, a third MOS tube Q3, a fourth MOS tube Q4, a fifth MOS tube Q5, a sixth MOS tube Q6, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14; One end of the second resistor R2 and one end of the fourth resistor R4 serve as input ends of the TEC driving circuit, and are sequentially connected to a PWM signal + and another complementary PWM signal - input by the PWM calculation unit, the other end of the second resistor R2 is respectively connected to one end of the third resistor R3 and the gate of the first MOS tube Q1, the other end of the third resistor R3 and the source of the first MOS tube Q1 are both grounded, the drain of the first MOS tube Q1 is respectively connected to one end of the first resistor R1 and the gate of the second MOS tube Q2, the other end of the first resistor R1 is respectively connected to the source of the second MOS tube Q2 and the One plate of the three capacitors C3 is connected and connected to the power supply voltage, the drain of the second MOS tube Q2 is respectively connected to the drain of the third MOS tube Q3, one end of the sixth resistor R6, one plate of the fourth capacitor C4 and the positive electrode of the TEC, the other end of the sixth resistor R6 is connected to the other plate of the third capacitor C3, the gate of the third MOS tube Q3 is respectively connected to the other end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fifth resistor R5, the source of the third MOS tube Q3 and one end of the seventh resistor R7 are all grounded, and the other end of the seventh resistor R7 is connected to the other plate of the fourth capacitor C4; One end of the eleventh resistor R11 and one end of the ninth resistor R9 serve as input ends of the TEC driving circuit, and are connected in sequence to a PWM signal + and another complementary PWM signal - input by the PWM calculation unit. The other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the gate of the fourth MOS tube Q4 respectively. Both ends of the tenth resistor R10 and the source of the fourth MOS tube Q4 are grounded. The drain of the fourth MOS tube Q4 is connected to one end of the eighth resistor R8 and the gate of the fifth MOS tube Q5 respectively. The other end of the eighth resistor R8 is connected to the source of the fifth MOS tube Q5 and the fifth capacitor C 5 is connected to one electrode plate of the fifth capacitor C5 and is connected to the power supply voltage, the other electrode plate of the fifth capacitor C5 is connected to one end of the thirteenth resistor R13, the drain of the fifth MOS tube Q5 is respectively connected to the other end of the thirteenth resistor R13, the drain of the sixth MOS tube Q6, one electrode plate of the sixth capacitor C6 and the negative electrode of TEC, the gate of the sixth MOS tube Q6 is respectively connected to one end of the twelfth resistor R12 and the other end of the eleventh resistor R11, the other end of the twelfth resistor R12, the source of the sixth MOS tube Q6 and one end of the fourteenth resistor are all grounded, and the other end of the fourteenth resistor is connected to the other electrode plate of the sixth capacitor C6.

5. The high-precision and high-power Raman light source laser temperature control system based on MFAC as claimed in claim 4, characterized in that: The first MOS transistor Q1 , the third MOS transistor Q3 , the fourth MOS transistor Q4 and the sixth MOS transistor Q6 are all NMOS transistors, and the second MOS transistor Q2 and the fifth MOS transistor Q5 are PMOS transistors.

6. The high-precision and high-power Raman light source laser temperature control system based on MFAC as claimed in claim 1, characterized in that: The PWM calculation unit uses the MFAC algorithm to calculate the PWM duty cycle according to the expected temperature and the actual temperature as follows: ； in, ； in, express The PWM duty cycle at the moment, express The PWM duty cycle at the moment, express The PWM duty cycle at the moment, Represents thermistor The actual temperature at the moment, Represents thermistor The actual temperature at the moment, , , and Both represent weight coefficients, Represents thermistor The expected temperature at the time, and the expected temperature at different times remains consistent, express The intermediate parameters of the moment, express Intermediate parameters of time.

7. The high-precision and high-power Raman light source laser temperature control system based on MFAC as claimed in claim 1, characterized in that: The temperature control system also includes a heat sink block arranged on the Raman light source laser housing.

8. The high-precision and high-power Raman light source laser temperature control system based on MFAC as claimed in claim 1, characterized in that: The temperature control system also includes a host computer, and the temperature stability judgment unit uploads the real-time actual temperature to the host computer for display.

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