Temperature control apparatus and method for operating a laser over a wide temperature range

Abstract

The application discloses a temperature control device and method for operating a laser in a wide temperature range, and belongs to the technical field of lasers.The device comprises: a heat dissipation base plate; a first semiconductor refrigerator arranged on the heat dissipation base plate and used for performing temperature control on a laser shell; at least one heating rod arranged in the heat dissipation base plate and used for providing auxiliary heating for a hot surface of the first semiconductor refrigerator; a second semiconductor refrigerator used for performing temperature control on a laser diode; a laser shell used for bearing the second semiconductor refrigerator; a first thermistor used for monitoring the temperature of the heat dissipation base plate; and a temperature control circuit board used for controlling the heating power of the heating rod and adjusting a target temperature control point of the first semiconductor refrigerator according to the working current of the second semiconductor refrigerator.The application realizes high-stable temperature control of the laser diode in a wide temperature range, guarantees long-life operation of the TEC and minimization of the total power of the system, and significantly improves energy efficiency and environmental adaptability.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, specifically relating to a temperature control device and method for a laser operating over a wide temperature range. Background Technology

[0002] Compact lasers, as core components, are widely used in devices such as lidar, handheld rangefinders, and low-altitude economical drones to generate high-peak-power, narrow-pulse-width laser pulses for long-range, high-precision 3D imaging and detection. To ensure the normal operation of semiconductor chips, thermoelectric coolers (TECs) are typically used as actuators, and negative temperature coefficient (NTC) thermistors as feedback elements to control the chip temperature within a normal range of 20-30°C. However, as applications expand to outdoor fields such as automotive and airborne systems, lasers must operate stably over an extremely wide temperature range of -40°C to 60°C, placing far more stringent demands on thermal management systems than traditional solutions.

[0003] The performance of semiconductor lasers is highly sensitive to temperature: the threshold current of a laser diode (LD) increases exponentially with temperature. Temperature rise leads to a significant decrease in photoelectric conversion efficiency, while temperature fluctuations cause center wavelength drift and output power jitter, directly affecting detection accuracy. Wide-range, high-precision temperature control presents an inherent contradiction—the wider the temperature control range, the more difficult it is to maintain sub-degree-level temperature control accuracy. Currently, the most commonly used TEC (thermal energy transfer) temperature control devices are severely limited by the temperature difference between the hot and cold sides: the cooling power on the high-temperature side decreases significantly, while on the low-temperature side, the temperature difference between the hot and cold sides may exceed limits due to excessively low hot-side temperatures, leading to drive current saturation, a coefficient of performance (COP) approaching zero, and loss of the ability to establish a temperature gradient. Simultaneously, semiconductor laser chips have small heat capacity and rapid changes in heating power; sudden changes in ambient temperature easily cause temperature jitter, requiring the temperature control system to have extremely high response speed.

[0004] Existing technologies have proposed various solutions to the above problems, but there are still obvious limitations: (1) By encapsulating heating elements inside the laser and coordinating temperature control with TEC, the limitations of a single TEC in a wide temperature environment can be solved. When the temperature difference is low, the TEC works independently, and when the temperature difference is high, the heating elements operate at different constant power. The heating power of this solution needs to be set by looking up a table, which is an open-loop feedforward compensation. It cannot be dynamically and adaptively adjusted according to the real-time operating current of the TEC. When the ambient temperature fluctuates greatly, the lookup value may be mismatched, causing the TEC to still work in the inefficient area or overheat and waste energy, and it cannot make the total power consumption of the system converge to the minimum; (2) Based on FPGA design, an anti-saturation proportional-integral-derivative PID control strategy is designed. The TEC graded control is used to achieve a temperature control accuracy of ±0.02℃ in the range of -45℃ to 75℃, which is an important step in wide temperature coverage. However, it does not actively constrain the operating current of each TEC and the total power consumption of the system. (2) Minimum-target optimization adjustment, under extremely low temperature conditions, a certain level of TEC may operate in the overload or extremely low COP range for a long time, with high power consumption; (3) Combining deep negative feedback inner loop and PID outer loop, a stability of ±0.005℃ can be achieved in 15~35℃, and a stability of ±0.002℃ can be achieved in 0~40℃ based on gallium nitride transistor and temperature-current dual closed loop strategy. These solutions have excellent temperature control accuracy, but the operating temperature range is narrow and cannot cover the temperature requirements from -40℃ to 60℃; (4) Using the integrated temperature control chip MAX1978 combined with analog PID, the stability is 0.03℃, but the analog PID parameter tuning is cumbersome and difficult to adjust quickly; (5) In the existing technology, there are also some ultra-stable linear temperature control modules that can reach ±0.01℃ in a short time. They also use analog PID, but they cannot monitor and adjust the temperature and PID parameters in real time and are limited in dynamic environment adaptability.

[0005] In summary, existing technologies cannot simultaneously satisfy: rapid and reliable startup and stable operation within an extremely wide temperature range (especially at extremely low temperatures) from -40℃ to 60℃; each TEC always operates in the high-efficiency current range to avoid overload or inefficient heat dissipation; and adaptively find the optimal balance point of the heater and multi-stage TEC power at the system level to minimize the total power. Specifically, existing technologies have the following problems: (1) The temperature difference between the hot and cold surfaces of the TEC exceeds the limit at low temperatures, resulting in saturation of the drive current and a decrease in the coefficient of performance to zero, making it impossible to establish a normal temperature control gradient; (2) Heating compensation mostly adopts an open-loop lookup table method, which cannot adaptively adjust according to the real-time working status of the TEC, and is prone to mismatch when the ambient temperature fluctuates; (3) The target temperature of each stage in the multi-stage TEC coupling control is rigidly set, and it is impossible to adaptively adjust the temperature control point of the front stage to adapt to the change of the heat load of the back stage; (4) There is a lack of optimized control with the goal of minimizing the total power of the system, and the total power consumption of the heater and multi-stage TEC remains high under low temperature conditions.

[0006] The aforementioned shortcomings have hindered the practical application and energy efficiency improvement of wide-temperature-range compact lasers, and there is an urgent need for a new temperature control technology that can overcome these defects. Summary of the Invention

[0007] The purpose of this invention is to provide a temperature control device and method for a laser operating in a wide temperature range, aiming to solve the problems existing in the current laser temperature control technology in a wide temperature range of -40℃ to 60℃, especially in extremely low temperature conditions.

[0008] To achieve the above objectives, the present invention provides a temperature control device for a laser operating over a wide temperature range. The device includes: a heat sink base; a first thermoelectric cooler disposed on the heat sink base for temperature control of the laser housing; at least one heating rod disposed in the heat sink base for providing auxiliary heating to the hot surface of the first thermoelectric cooler; a second thermoelectric cooler for temperature control of the laser diode; a laser housing disposed between the first and second thermoelectric coolers for supporting the second thermoelectric cooler, wherein the second thermoelectric cooler is fixedly disposed on the bottom surface of the inner cavity of the laser housing and is in direct contact with the laser housing; a first thermistor for monitoring the temperature of the heat sink base; and a temperature control circuit board electrically connected to the first thermoelectric cooler, the heating rod, the second thermoelectric cooler, and the first thermistor, respectively, for controlling the heating power of the at least one heating rod based on the temperature of the heat sink base and the operating current of the first thermoelectric cooler, and adjusting the target temperature control point of the first thermoelectric cooler based on the operating current of the second thermoelectric cooler.

[0009] Accordingly, the present invention also provides a temperature control method for a wide-temperature-range laser, used in the temperature control device for the aforementioned wide-temperature-range laser. This method is implemented via a temperature control circuit board and includes: Step S1, when the temperature of the heat sink base plate is lower than a preset temperature threshold, controlling at least one heating rod to output initial heating power to reduce the temperature difference between the hot and cold surfaces of the first semiconductor cooler; Step S2, when the first operating current of the first semiconductor cooler exceeds a first preset current range, adjusting the heating power of at least one heating rod to bring the first operating current back to the first preset current range; Step S3, when the second operating current of the second semiconductor cooler exceeds a second preset current range, adjusting the target temperature control point of the first semiconductor cooler to bring the second operating current back to the second preset current range; Step S4, when the first operating current is within the first preset current range and the second operating current is within the second preset current range, optimizing the target temperature control point of the first semiconductor cooler using a hill-climbing method with the goal of reducing the total power of the system.

[0010] The beneficial effects of this invention are as follows:

[0011] (1) Wide temperature range reliable start-up: By embedding heating rods in the heat dissipation base plate, the hot surface of the first semiconductor cooler is assisted in heating at low temperature, and the temperature difference between the hot and cold surfaces is controlled within the allowable range, fundamentally solving the problem that the TEC cannot work at extremely low temperatures, and achieving reliable start-up and stable operation in the full temperature range from -40℃ to 60℃.

[0012] (2) TEC operates efficiently throughout: The current constraint control strategy is adopted, and the heating power or the target temperature control point of the front stage is dynamically adjusted based on the real-time operating current of each TEC stage. This ensures that each TEC stage always operates in the current range with a high COP, avoids overload or inefficient heat dissipation, and extends the device life.

[0013] (3) Adaptive minimization of total system power consumption: Taking the total power of the heating rod and the two-stage TEC as the optimization target, the optimal target temperature control point of the first semiconductor cooler is automatically searched by the hill climbing method, so that the system converges to the thermal equilibrium state with the lowest power consumption, effectively solving the problem of high power consumption in the existing open-loop compensation scheme;

[0014] (4) Full closed-loop adaptive adjustment: Unlike the existing open-loop lookup table method, the control of this invention is based entirely on TEC real-time current feedback, which can automatically adapt to changes in ambient temperature, device aging and thermal load fluctuations, without the need for manual calibration of parameter tables, and has strong engineering adaptability. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0016] Figure 1 A schematic diagram of the temperature control device for a wide-temperature-range laser provided by the present invention;

[0017] Figure 2 The control flowchart of the temperature control method for a wide-temperature-range laser provided by the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, this invention adopts the following technical solution.

[0019] Figure 1Figure 1 shows a schematic diagram of the temperature control device for a wide-temperature-range laser provided by the present invention. The device includes a heat dissipation base plate 1, a first semiconductor cooler 2, a laser housing 3, a heating rod 4, a second semiconductor cooler 5, a carrier plate 6, a laser diode 7, a first thermistor 8, a second thermistor 9, and a third thermistor 10.

[0020] The following is combined Figure 1 The temperature control device for a wide-temperature-range laser provided by this invention is described in detail.

[0021] The temperature control device for a wide-temperature-range operating laser provided by the present invention includes:

[0022] Heat dissipation base plate 1;

[0023] The first semiconductor cooler 2, used as a thermoelectric cooler for the laser housing, is mounted on the heat dissipation base plate 1 and is used to perform temperature control of the laser housing;

[0024] At least one heating rod 4 is disposed in the heat dissipation base plate 1 for providing auxiliary heating to the hot surface of the first semiconductor cooler 2; furthermore, at least one heating rod 4 is used to provide auxiliary heating to the hot surface of the first semiconductor cooler 2 under low temperature conditions, wherein the low temperature conditions refer to the temperature of the heat dissipation base plate being lower than 0°C or lower than the rated minimum operating temperature of the first semiconductor cooler 2, with a wide temperature range of -40°C to 60°C.

[0025] The second semiconductor cooler 5 is used as a thermoelectric cooler for the laser diode and is used to perform temperature control of the laser diode.

[0026] The laser housing 3 is disposed between the first semiconductor cooler 2 and the second semiconductor cooler 5, and is used to support the second semiconductor cooler 5. The second semiconductor cooler 5 is fixedly disposed on the bottom surface of the inner cavity of the laser housing 3, and the second semiconductor cooler 5 is in direct contact with the laser housing 3.

[0027] The first thermistor 8 is used to monitor the temperature of the heat dissipation base plate 1;

[0028] The temperature control circuit board is electrically connected to the first semiconductor cooler 2, the heating rod 4, the second semiconductor cooler 5 and the first thermistor 8 respectively. It is used to control the heating power of at least one heating rod 4 according to the temperature of the heat sink base plate 1 and the operating current of the first semiconductor cooler 2, and to adjust the target temperature control point of the first semiconductor cooler 2 according to the operating current of the second semiconductor cooler 5.

[0029] like Figure 1 As shown, the temperature control device for a wide-temperature-range laser also includes:

[0030] The second thermistor 9 is used to monitor the temperature of the laser housing 3;

[0031] The third thermistor 10 is used to monitor the temperature of the laser diode 7.

[0032] Carrier plate 6 is disposed on the second semiconductor cooler 5;

[0033] Laser diode 7, mounted on carrier plate 6, is used to generate laser pulses;

[0034] The temperature control circuit board is electrically connected to the heating rod 4, the first semiconductor cooler 2, the second semiconductor cooler 5, the first thermistor 8, the second thermistor 9, and the third thermistor 10, respectively.

[0035] At least one heating rod 4 is four heating rods 4, and they are evenly distributed in the heat dissipation base plate 1.

[0036] The carrier plate 6 is made of oxygen-free copper, and thermally conductive interface materials are respectively provided between the carrier plate 6 and the second semiconductor cooler 5 and between the laser diode 7 and the carrier plate 6.

[0037] The heat dissipation base plate 1, serving as the final interface for heat exchange between the device and the external environment, is made of a copper alloy with high thermal conductivity. Its bottom surface can be fitted with heat dissipation fins or connected to a larger external heat sink as needed. One or more blind holes are provided inside the heat dissipation base plate 1 for embedding heating rods 4. In this embodiment, four heating rods 4 are preferably evenly distributed around the mounting area of ​​the first semiconductor cooler 2 within the heat dissipation base plate 1 to ensure uniform auxiliary heating of the hot surface of the first semiconductor cooler 2. The heating rods 4 can be resistance heating rods, with the heating power adjusted by a temperature control circuit board via pulse width modulation (PWM) or linear drive.

[0038] The first thermoelectric cooler 2, also known as the laser housing thermoelectric cooler TEC, is disposed on the upper surface of the heat dissipation base plate 1. The lower surface of the first thermoelectric cooler 2 is the hot surface and is in close contact with the heat dissipation base plate 1, while the upper surface is the cold surface. The laser housing 3 is disposed above the first thermoelectric cooler 2, with its bottom surface in close contact with the cold surface of the first thermoelectric cooler 2. A cavity is formed inside the laser housing 3 to accommodate the second thermoelectric cooler 5 and related optical components. The laser housing 3 itself is made of a metal material with good thermal conductivity (such as aluminum alloy) to reduce thermal resistance.

[0039] The second thermoelectric cooler 5, namely the laser diode thermoelectric cooler LD TEC, is fixedly disposed on the bottom surface of the inner cavity of the laser housing 3, so that the lower surface (hot surface) of the second thermoelectric cooler 5 is in direct contact with the laser housing 3, and a low thermal resistance heat conduction path is formed between the cold surface of the first thermoelectric cooler 2 and the hot surface of the second thermoelectric cooler 5. The carrier plate 6 is disposed on the upper surface (cold surface) of the second thermoelectric cooler 5, and the laser diode 7 is directly mounted on the carrier plate 6. To minimize the contact thermal resistance, the carrier plate 6 is preferably made of oxygen-free copper; the space between the carrier plate 6 and the second thermoelectric cooler 5, as well as the space between the laser diode 7 and the carrier plate 6, is filled with a thermally conductive interface material, such as indium foil.

[0040] like Figure 1 As shown, the first thermistor 8 is embedded in the heat sink base plate 1, adjacent to the hot surface of the first thermoelectric cooler 2, and is used to monitor the temperature of the heat sink base plate 1 in real time. The second thermistor 9 is disposed on the laser housing 3, preferably close to the bottom of the housing near the cold surface of the first thermoelectric cooler 2, and is used to monitor the temperature of the laser housing. The third thermistor 10 is disposed on the carrier plate 6, adjacent to the laser diode 7, and is used to directly monitor the temperature of the laser diode 7. The three thermistors, the first thermistor 8, the second thermistor 9, and the third thermistor 10, are all high-precision negative temperature coefficient thermistors, and their signal lines are connected to the temperature control circuit board.

[0041] The temperature control circuit board mainly includes a microcontroller, a TEC drive circuit, a heating rod drive circuit, and a thermistor signal acquisition circuit. The microcontroller reads the sampled values ​​from three thermistors (first thermistor 8, second thermistor 9, and third thermistor 10) and performs analog-to-digital conversion to obtain the real-time temperatures of the heat sink 1, the laser housing 3, and the laser diode 7, and executes a preset control algorithm accordingly. The control signals output by the microcontroller drive the first semiconductor cooler 2, the second semiconductor cooler 5, and the heating rod 4, respectively. The TEC drive circuit can use an integrated TEC control chip such as the MAX1978, which changes the amplitude and direction of the current flowing through the TEC to achieve cooling or heating; the heating rod drive circuit can adjust the current duty cycle of the heating rod 4 through a power transistor, thereby controlling its heating power.

[0042] Figure 2 The control flowchart of the temperature control method for a wide-temperature-range laser provided by this invention is shown below. Figure 1 The device shown Figure 2 The specific control process is described in detail.

[0043] The temperature control method for a wide-temperature-range operating laser provided by this invention is used in the temperature control device for the wide-temperature-range operating laser described above. This method is implemented via a temperature control circuit board and includes:

[0044] Step S1: When the temperature of the heat dissipation base plate 1 is lower than the preset temperature threshold, control at least one heating rod 4 to output initial heating power to reduce the temperature difference between the hot and cold surfaces of the first semiconductor cooler 2; Step S1 is the first operating current constraint control stage of the first semiconductor cooler 2.

[0045] Before step S1, there is a low-temperature start-up phase. During the low-temperature start-up phase, the ambient temperature, the base plate temperature, the laser housing 3 temperature and the laser diode 7 temperature are detected, the parameters are initialized, and the base plate heating rod 4 and the first semiconductor cooler 2 are turned on.

[0046] Step S2: When the first operating current of the first semiconductor cooler 2 exceeds the first preset current range, adjust the heating power of at least one heating rod 4 to bring the first operating current back to the first preset current range.

[0047] Step S3: When the second operating current of the second semiconductor cooler 5 exceeds the second preset current range, the second operating current is brought back to the second preset current range by adjusting the target temperature control point of the first semiconductor cooler 2.

[0048] Step S4: When the first operating current is in the first preset current range and the second operating current is in the second preset current range, the target temperature control point of the first semiconductor cooler 2 is optimized by using the hill climbing method with the goal of reducing the total power of the system.

[0049] Step S2, the first operating current constraint control stage of the first semiconductor cooler 2, includes: real-time monitoring of the first operating current of the first semiconductor cooler 2. When the first operating current Exceeding the first preset current range At that time, if Then increase the heating power of at least one heating rod 4. Then reduce the heating power of at least one heating rod 4 until the first operating current is reached. Returning to the first preset current range, where, This is the lower limit of the first preset current range. This is the upper limit of the first preset current range. Furthermore, when the first operating current of the first semiconductor cooler 2 is detected... When the value is negative (cooling mode), the power of heating rod 4 will be reduced to the standby value or the heating rod 4 will be turned off.

[0050] Among them, when This indicates that the TEC's hot surface temperature is too low and the temperature difference between the hot and cold surfaces is too large, resulting in insufficient heating power and the operating current exceeding the upper limit of the range. The heating efficiency of the TEC can be improved by increasing the hot surface temperature and reducing the temperature difference between the hot and cold surfaces. If the temperature of the hot side of the TEC is too high and the temperature difference between the hot and cold sides is too small, its heating power is redundant and the operating current is lower than the lower limit of the range. The heating efficiency of the TEC can be reduced by lowering the temperature of the hot side of the TEC and increasing the temperature difference between the hot and cold sides of the TEC.

[0051] Step S3 includes a second operating current constraint control stage for the second semiconductor cooler 5, comprising: real-time monitoring of the second operating current of the second semiconductor cooler 5. When the second operating current Exceeding the second preset current range At that time, by adjusting the target temperature control point of the first semiconductor cooler 2 , so that the second operating current Returning to the second current range, where, if Then increase the target temperature control point ,like Then reduce the target temperature control point. ,in, This is the lower limit of the second preset current range. This is the upper limit of the second preset current range.

[0052] Step S4 includes the optimization phase for minimizing the total system power, including: when the first operating current... And the second operating current At that time, the total electrical power of the system To optimize the objective, The hill-climbing method was used to determine the target temperature control point of the first semiconductor cooler (2). Perform disturbance optimization to reduce the total power of the system. It converges to the minimum value, where, For the output power of heating rod 4, The electrical power of the first semiconductor cooler 2 This is the electrical power of the second semiconductor cooler 5.

[0053] In step S4, the hill-climbing method includes:

[0054] Step S41, Measure the current total power of the system. ;

[0055] Step S42, with temperature step size Adjust the target temperature control point of the first semiconductor cooler 2;

[0056] Step S43: Measure the new total power of the system after adjusting the target temperature control point of the first semiconductor cooler 2. ;

[0057] Step S44, if If so, maintain the current temperature adjustment direction. Then the temperature adjustment direction will be reversed, and the new total power of the system will be used. Update the system's current total power. ;

[0058] Repeat steps S42 to S44 until continuous. The new total power of the system in use during the next adjustment Update the system's current total power. Previously satisfied Furthermore, the laser diode 7 has a stable temperature. To preset the threshold for total power change, The preset number of adjustments is defined as follows: the temperature of laser diode 7 is stabilized when the temperature change of the diode is less than the preset temperature change threshold for N consecutive control cycles. M and N are both positive integers, and the control cycle is a preset fixed time period.

[0059] Temperature step The value range is 0.1℃~1.0℃, N control cycles are 5 control cycles, the preset number of adjustments M is 3, and the preset total power change threshold is [value missing]. Less than 1% of the system's rated total power.

[0060] After step S2, once the temperature of the laser housing 3 has stabilized, the second semiconductor cooler 5 is activated, and the process proceeds to step S3. The method for determining the temperature stability of the laser housing 3 is as follows: the temperature change within N consecutive control cycles is less than a preset threshold. The laser housing 3 is considered stable when the temperature change within N consecutive control cycles is less than the preset threshold. Furthermore, step S2 is repeated until the temperature of the laser housing 3 stabilizes, at which point the process proceeds to step S3.

[0061] In step S3, the monitoring can be repeated after the system stabilizes. System stabilization means that the temperature of the laser housing 3 and the temperature of the laser diode 7 are stable. Specifically, the temperature of the laser diode 7 is stable when the temperature change of the laser diode 7 is less than a preset threshold for the temperature change of the laser diode 7 within N consecutive control cycles.

[0062] In step S4, when the total power of the system... The change is less than the preset change threshold. Furthermore, once the temperature of laser diode 7 stabilizes, temperature control ends, and the system enters steady-state operation. Additionally, during the hill-climbing method, after each adjustment of the temperature step size, N control cycles can be waited for the system to reach thermal stability.

[0063] First preset current range Second preset current range The first semiconductor cooler 2 and the second semiconductor cooler 5 can be calibrated according to their performance curves and rated currents, so that the first semiconductor cooler 2 maintains a coefficient of performance (COP) higher than a preset coefficient (e.g., Coefficient of Performance, COP≥1.5) within the first preset operating current range and the second semiconductor cooler 5 maintains a coefficient of performance (COP) higher than a preset coefficient (e.g., Coefficient of Performance, COP≥1.5) within the second preset operating current range, and does not exceed the maximum allowable current.

[0064] Before step S1, parameters need to be initialized, specifically including: calculating the initial power of the heating rod 4 based on the ambient temperature using a table or formula, and setting the initial target temperature control point of the first semiconductor cooler 2 and the target temperature control point of the second semiconductor cooler 5. .

[0065] The present invention will now be described in more detail in stages through specific implementation methods.

[0066] Phase 1, Low-Temperature Startup and Initialization Phase:

[0067] After the system is powered on, the temperature control circuit board detects the temperatures of the heat sink 1, the laser housing 3, and the laser diode 7 via the first thermistor 8, the second thermistor 9, and the third thermistor 10, respectively. It determines whether the system has entered a low-temperature operating condition based on the temperature of the heat sink 1: if the temperature of the heat sink 1 is lower than a preset first threshold (e.g., 0°C), it is determined to be a low-temperature start. At this time, the microcontroller calculates the initial heating power of the heating rod 4 based on the heat sink temperature using a preset formula or by looking up a table, and outputs a drive signal to turn on the heating rod 4 for preheating. Simultaneously, the first semiconductor cooler 2 is started, and its initial target temperature control point is set to a conservative value (e.g., 10-15°C higher than the ambient temperature), starting operation with a smaller initial current. The auxiliary heating of the heating rod 4 causes the hot surface temperature of the first semiconductor cooler 2 to rise rapidly, compressing the temperature difference between the hot and cold surfaces to an allowable range, avoiding current saturation and COP decay.

[0068] The second stage, the first semiconductor cooler current constraint control stage:

[0069] After startup, the temperature control circuit board monitors the first operating current of the first semiconductor cooler 2 in real time. The first operating current and the preset first preset current range. Comparison: If This indicates that the cooling load of the first semiconductor cooler 2 is too high, and the hot surface temperature is still too low. The microcontroller increases the heating power output of the heating rod 4. (And not in cooling mode), indicating that the heating is excessive, the microcontroller reduces the heating power output of heating rod 4.

[0070] The above adjustments are repeated in a control cycle (the control cycle is a preset fixed time period, such as 500ms) until the temperature of the laser housing 3 stabilizes and the first operating current... Return and stay Within the interval. When detected When the value is negative (i.e., the first semiconductor cooler is operating in heating mode), the heating rod 4 is turned off directly or the heating power is reduced to the standby value to avoid reverse compensation.

[0071] The third stage, the start-up stage of the second semiconductor cooler:

[0072] Once the laser housing 3 reaches a stable temperature, the temperature control circuit board activates the second semiconductor cooler 5 and sets its target temperature control point to the optimal operating temperature of the LD (e.g., 25°C). Initially, it starts with a low drive current to minimize disturbance to the already stabilized thermal environment.

[0073] The fourth stage, the second semiconductor cooler current constraint control stage:

[0074] After the second semiconductor cooler 5 is started, the second operating current is monitored in real time. and with the preset second current range Comparison: If This indicates that the temperature of the hot surface (i.e., the laser housing) of the second semiconductor cooler 5 is too low, resulting in an excessive cooling load. At this point, the microcontroller raises the target temperature control point of the first semiconductor cooler 2. This causes the temperature of the laser housing 3 to rise moderately, thereby reducing the cooling load on the second semiconductor cooler 5; if Then reduce This causes the shell temperature to drop moderately. Each adjustment... After that, wait One control cycle (e.g.) Comparison will be made after the system has regained thermal stability. The relationship with the preset interval is repeated in this way until... Return and stay Within the range, and LD temperature It stabilizes within the allowable deviation range of the target value.

[0075] Fifth stage, total power minimization optimization stage:

[0076] When the first operating current of the first semiconductor cooler 2 The second operating current of the second semiconductor cooler 5 When all currents are within their respective preset current ranges and the LD temperature is stable, the system enters the total power optimization phase. The temperature control circuit board calculates the current total system power. and with Minimize the target temperature; use the hill-climbing method to determine the target temperature control point of the first semiconductor cooler 2. Optimization is performed. The specific steps of the hill climbing method are as follows: (1) Measure the current total power of the system, denoted as . (2) Using temperature step size (e.g., 0.2℃) Adjust the target temperature control point of the first semiconductor cooler 2; (3) Wait One control cycle (e.g.) (3) To bring the system to a new thermal equilibrium state; (4) Measure the new total electrical power of the system after adjustment. (5) Comparison and :like This indicates that the current adjustment direction reduces the total power of the system. Maintaining this direction and using the adjusted new total power of the system... Update the system's current total power. ;like Then, the temperature step size is adjusted in the opposite direction, and the new total power of the adjusted system is used. Update the system's current total power. (6) Repeat steps (2) to (5) until continuous. Next (such as) After adjustment, the new total power of the system is used. Update the system's current total power. All previously met ( For example, if the power is 1% of the system's rated total power, and the LD temperature remains stable, then the optimization process ends.

[0077] In the process of seeking the best, if because Changes led to or If the current exceeds its preset range again, the optimization will be paused, and the corresponding current constraint control will be executed first. The optimization will resume after the current returns to the range.

[0078] Sixth stage, steady-state operation stage:

[0079] Once the total system power meets the convergence condition and the LD temperature remains stable, the system exits the optimization mode, locks the current optimal control parameters, and enters steady-state operation. In this mode, the LD temperature is maintained constant solely through lightweight PID control. Simultaneously, the temperature control circuit board continuously monitors various temperature and current parameters in the background; if a sudden change in ambient temperature or a sudden change in thermal load is detected... or If the limit is exceeded, the system automatically exits steady state and re-enters the corresponding current constraint control or optimization stage to achieve adaptive and efficient operation under all working conditions.

[0080] In one embodiment of the invention, the ambient temperature is -40°C. The temperature of the heat dissipation base plate 1 is extremely low, and the first semiconductor cooler 2 cannot be directly started. The system controls the heating rod 4 to output initial heating power, and after about 30 seconds, the hot surface of the first semiconductor cooler 2 is heated to the working temperature range, and its operating current drops from the saturation state to the preset current range. After the shell temperature stabilizes, the second semiconductor cooler 5 is started. Through current constraint and hill climbing optimization, the LD temperature is stabilized at 25°C ± 0.01°C. The total power consumption of the system is reduced by about 28% compared with the traditional fixed heating power scheme.

[0081] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0082] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0083] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. A temperature control device for a laser operating over a wide temperature range, characterized in that, The device includes: Heat dissipation base plate (1); The first semiconductor cooler (2) is mounted on the heat dissipation base plate (1) and is used to perform temperature control of the laser housing; At least one heating rod (4) is disposed in the heat dissipation base plate (1) for providing auxiliary heating to the hot surface of the first semiconductor cooler (2); The second semiconductor cooler (5) is used to perform temperature control of the laser diode; The laser housing (3) is disposed between the first semiconductor cooler (2) and the second semiconductor cooler (5) for supporting the second semiconductor cooler (5), wherein the second semiconductor cooler (5) is fixedly disposed on the bottom surface of the inner cavity of the laser housing (3) and the second semiconductor cooler (5) is in direct contact with the laser housing (3); The first thermistor (8) is used to monitor the temperature of the heat dissipation base plate (1); The temperature control circuit board is electrically connected to the first semiconductor cooler (2), the heating rod (4), the second semiconductor cooler (5) and the first thermistor (8) respectively. It is used to control the heating power of at least one heating rod (4) according to the temperature of the heat sink (1) and the working current of the first semiconductor cooler (2), and to adjust the target temperature control point of the first semiconductor cooler (2) according to the working current of the second semiconductor cooler (5).

2. The temperature control device for a wide-temperature-range operating laser according to claim 1, characterized in that, The device also includes: The second thermistor (9) is used to monitor the temperature of the laser housing (3); The third thermistor (10) is used to monitor the temperature of the laser diode (7); The carrier plate (6) is disposed on the second semiconductor cooler (5); A laser diode (7) is disposed on the carrier plate (6) for generating laser pulses; The temperature control circuit board is electrically connected to the heating rod (4), the first semiconductor cooler (2), the second semiconductor cooler (5), the first thermistor (8), the second thermistor (9) and the third thermistor (10), respectively.

3. The temperature control device for a wide-temperature-range operating laser according to claim 2, characterized in that, The at least one heating rod (4) consists of four heating rods (4) and are evenly distributed in the heat dissipation base plate (1).

4. The temperature control device for a wide-temperature-range operating laser according to claim 3, characterized in that, The carrier plate (6) is made of oxygen-free copper, and thermally conductive interface materials are respectively provided between the carrier plate (6) and the second semiconductor cooler (5) and between the laser diode (7) and the carrier plate (6).

5. A temperature control method for a wide-temperature-range operating laser, used in the temperature control device for the wide-temperature-range operating laser as described in any one of claims 1 to 4, characterized in that, This method is implemented through a temperature control circuit board and includes: Step S1: When the temperature of the heat dissipation base plate (1) is lower than the preset temperature threshold, control at least one heating rod (4) to output initial heating power to reduce the temperature difference between the hot and cold surfaces of the first semiconductor cooler (2). Step S2: When the first operating current of the first semiconductor cooler (2) exceeds the first preset current range, adjust the heating power of at least one heating rod (4) to bring the first operating current back to the first preset current range. Step S3: When the second operating current of the second semiconductor cooler (5) exceeds the second preset current range, the second operating current is brought back to the second preset current range by adjusting the target temperature control point of the first semiconductor cooler (2). Step S4: When the first operating current is in the first preset current range and the second operating current is in the second preset current range, the total power of the system is reduced. To achieve the target, the hill-climbing method is used to optimize the target temperature control point of the first semiconductor cooler (2), wherein, , For the output power of the heating rod (4), The electrical power of the first semiconductor cooler (2) The electrical power of the second semiconductor cooler (5).

6. The temperature control method for a wide-temperature-range operating laser according to claim 5, characterized in that, Step S2 includes a first operating current constraint control stage for the first semiconductor cooler (2), comprising: Real-time monitoring of the first operating current of the first semiconductor cooler (2) When the first operating current Exceeding the first preset current range At that time, if If the heating power of at least one heating rod (4) is increased, then the heating power of the heating rod (4) will be increased. Then reduce the heating power of at least one heating rod (4) until the first operating current is reached. Returning to the first preset current range, where, This is the lower limit of the first preset current range. This is the upper limit of the first preset current range.

7. The temperature control method for a wide-temperature-range operating laser according to claim 6, characterized in that, Step S3 includes a second operating current constraint control stage for the second semiconductor cooler (5), comprising: Real-time monitoring of the second operating current of the second semiconductor cooler (5) When the second operating current Exceeding the second preset current range At that time, the target temperature control point of the first semiconductor cooler (2) is adjusted. This enables the second operating current. Returning to the second current range, where, if Then increase the target temperature control point ,like Then reduce the target temperature control point. ,in, This is the lower limit of the second preset current range. This is the upper limit of the second preset current range.

8. The temperature control method for a wide-temperature-range operating laser according to claim 7, characterized in that, Step S4 includes a total system power minimization optimization phase, comprising: When the first operating current And the second operating current At that time, the total electrical power of the system To optimize the target, the hill-climbing method is used to determine the target temperature control point of the first semiconductor cooler (2). Perform disturbance optimization to reduce the total power of the system. It converges to the minimum value.

9. The temperature control method for a wide-temperature-range operating laser according to claim 8, characterized in that, In step S4, the hill-climbing method includes: Step S41, Measure the current total power of the system. ; Step S42, with temperature step size Adjust the target temperature control point of the first semiconductor cooler (2); Step S43: Measure the new total power of the system after adjusting the target temperature control point of the first semiconductor cooler (2). ; Step S44, if If so, maintain the current temperature adjustment direction. Then the temperature adjustment direction will be reversed, and the new total power of the system will be used. Update the system's current total power. ; Repeat steps S42 to S44 until continuous. The new total power of the system in use during the next adjustment Update the system's current total power. Previously satisfied Furthermore, the laser diode (7) has a stable temperature, among which, To preset the threshold for total power change, The preset number of adjustments is defined as follows: the temperature of the laser diode (7) is stable when the temperature change of the diode is less than the preset temperature change threshold within N consecutive control cycles. M and N are both positive integers, and the control cycle is a preset fixed time period.

10. The temperature control method for a wide-temperature-range operating laser according to claim 9, characterized in that, The temperature step The value range is 0.1℃~1.0℃, N control cycles are 5 control cycles, the preset number of adjustments M is 3, and the preset total power change threshold is [value missing]. Less than 1% of the system's rated total power.

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