CN106802679A - A kind of low interference driving method and the device of high power for TEC - Google Patents

Abstract

The invention discloses a high-power low-interference driving method and device for a thermoelectric refrigerator. The related devices include: a host computer, an MCU controller, a voltage-controlled DC output power drive circuit, a noise processing module, a TEC module, and a temperature measurement module ; Among them, the upper computer, MCU controller, voltage-controlled DC output power drive circuit, noise processing module and TEC module are connected in sequence; one end of the temperature measurement module is connected to the TEC module, and the other end is connected to the MCU controller. It adopts the method of digital PID, and generates a DC driving voltage signal through a voltage-controlled DC output power drive circuit with voltage feedback control at the same time, controls the voltage-controlled DC output power drive circuit through the control level signal, and finally After the noise processing module, a low-noise interference DC power drive signal is generated to drive the TEC module, and then through the detection of the TEC temperature and the feedback digital PID adjustment, a high-precision, low-noise and high-power TEC drive scheme is realized.

Description

A high-power low-interference driving method and device for a thermoelectric refrigerator

technical field

The invention relates to the field of temperature control driving of semiconductor thermoelectric coolers (TECs), in particular to a high-power and low-interference driving method and device for thermoelectric coolers.

Background technique

In the field of photoelectric detection, semiconductor detectors are mostly used, such as infrared detectors, scientific grade CCD detectors or sCMOS detectors. They are very sensitive to temperature and generally require refrigeration to reduce the noise impact of temperature. Due to considerations of size, applicability and convenience, many semiconductor detectors use semiconductor thermoelectric cooling modules (TEC) with high cooling precision and easy control. Limited by the size of the detector and the target temperature, the TEC used for semiconductor detectors generally requires a very low cooling temperature, and the input power is as high as tens of watts to hundreds of watts. At the same time, the TEC module is generally closely connected with the semiconductor detector, so if the driving circuit part of the TEC module has a large noise, it will have a great impact on the extremely sensitive semiconductor detector.

At present, there are mainly two schemes for the power drive of TEC: digital PID drive control and analog PID drive control. Most schemes using digital PID drive control are to perform digital PID calculation through a controller, and then generate a set of PWM drive signals through the H bridge, and control the drive power of the TEC by adjusting the duty cycle of the PWM signal. This method can achieve high-precision, high-efficiency power drive for TEC, and can digitally adjust the parameters of PID, but it also has obvious shortcomings: PWM direct drive method is to generate a duty ratio The pulse signal of this kind of large current and high frequency will bring obvious noise influence to the detector and its drive circuit for weak signal detection, and the interference it will bring will greatly reduce the imaging of the detector quality.

The TEC drive scheme using analog PID drive control needs to adjust the parameters of the PID by adjusting the analog circuit. In this way, the drive power can not be controlled by the duty cycle of the PWM, but by generating a feedback adjustable voltage signal. Controlling the driving power can effectively avoid the noise effect caused by the PWM pulse signal, but this method also has disadvantages: the analog PID driving method uses an analog PID feedback control circuit, and it is necessary to adjust the parameters of the analog circuit to change the three parameters of the PID. The debugging process is very cumbersome and time-consuming, and has high requirements for regulators. Unlike the digital PID algorithm, which can be conveniently and quickly adjusted in real time, its adaptability and ease of use are poor.

Contents of the invention

The object of the present invention is to provide a high-power and low-interference driving method and device for thermoelectric refrigerators. Using a digital PID control scheme, the driving signal can provide relatively large power, and at the same time has very low noise, which is not easy for other sensitive circuits. It is especially suitable for cooling systems of infrared detectors, scientific grade CCD detectors or sCMOS detectors.

The purpose of the present invention is achieved through the following technical solutions:

A high-power low-interference driving device for a thermoelectric refrigerator, including: a host computer, an MCU controller, a voltage-controlled DC output power drive circuit, a noise processing module, a TEC module, and a temperature measurement module; wherein, the host computer and the MCU control The device, the voltage-controlled DC output power drive circuit, the noise processing module and the TEC module are connected in sequence; one end of the temperature measurement module is connected to the TEC module, and the other end is connected to the MCU controller.

The upper computer and the MCU controller perform data communication through a serial port, a USB interface, a PCI bus, a WIFI interface, a Bluetooth interface, or a network interface.

Described MCU controller comprises: PID algorithm module, communication interface module, DAC and SPI interface; Wherein, communication interface module realizes the data communication of MCU controller and upper computer, SPI interface realizes the data communication of MCU controller and temperature measuring module, The PID algorithm module performs real-time digital PID calculation according to the target temperature data received by the communication interface module and the temperature monitoring data received by the SPI interface to obtain the power value to be output; the DAC outputs a power control voltage to the voltage control according to the power value calculated by the PID algorithm module DC output power drive circuit.

The voltage-controlled DC output power drive circuit includes: a DC-DC controller and its peripheral MOSFETs and inductance and capacitance; the DC-DC controller has control voltage input and feedback voltage input pins, and internally controls the control voltage and feedback voltage. Compare and dynamically adjust the duty cycle of the PWM signal controlling the external MOSFET, and the output of the MOSFET is converted into a DC signal with a certain ripple through the preset inductance and capacitance; then the output DC signal is fed back to the feedback voltage of the DC-DC controller The input pin realizes the precise follow-up of the output voltage to the input control voltage.

The noise processing module includes: a common-mode inductor and an LC-type filter network connected in sequence; wherein, the common-mode inductor is used to filter the common-mode noise in the output signal of the voltage-controlled DC output power drive circuit, and the LC-type filter network is used to filter The differential mode noise in the output signal of the voltage-controlled DC output power driving circuit is removed.

The TEC module is placed in a closed or vacuum cavity, the cold end cools the target detector, and the hot end dissipates heat through a radiator, air cooling or water cooling.

The temperature measuring module includes: a temperature sensor and a temperature measuring circuit connected in sequence; wherein: the temperature sensor is a resistive temperature sensor, a thermocouple or a thermistor; the temperature measuring circuit is a bridge temperature measuring circuit, a constant current source type Temperature measurement circuit or integrated temperature measurement chip.

A high-power low-interference driving method for a thermoelectric refrigerator is implemented based on the aforementioned device, and the process is as follows:

The upper computer sends the target temperature data, PID parameters and start working instructions to the MCU controller, and obtains and displays the temperature data sent by the temperature measurement module to the TEC module of the MCU controller;

According to the target temperature set by the host computer and the cooling temperature of the TEC module detected by the temperature measurement module, the MCU controller implements the PID algorithm on-chip, calculates the output power value according to the result of the PID algorithm, and uses this power value output a power control voltage;

The voltage-controlled DC output power drive circuit with input following function follows the power control voltage output by the MCU controller, outputs a driving voltage signal whose voltage is proportional to the input reference voltage, and then filters it through the noise processing module as a low-noise The driving signal directly drives the TEC module;

The temperature change of the TEC module is collected by the temperature measurement module and fed back to the MCU controller. The MCU controller repeats the PID operation at a certain frequency, and continuously adjusts the control voltage signal according to the PID operation result, and then controls and drives the TEC. The power of the module brings the cooling temperature of the TEC module to the target temperature.

It can be seen from the above-mentioned technical solution provided by the present invention that a digital PID method is adopted, and at the same time, a voltage-controlled DC output power drive circuit with voltage feedback control is used to generate a DC driving voltage signal, and the voltage is controlled by controlling the level signal. Control the DC output power drive circuit, and finally pass through the noise processing module to generate a low-noise interference DC power drive signal to drive the TEC module, and then detect the TEC temperature and feedback digital PID adjustment to achieve high High-precision low-noise high-power TEC drive scheme.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings on the premise of not paying creative work.

Fig. 1 is a schematic structural diagram of a high-power low-interference driving device for a thermoelectric cooler provided by an embodiment of the present invention;

Fig. 2 is the structural representation of the MCU controller provided by the embodiment of the present invention;

FIG. 3 is a schematic diagram of a voltage-controlled DC output power drive circuit provided by an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

An embodiment of the present invention provides a high-power low-interference drive device for a thermoelectric cooler, as shown in Figure 1, which mainly includes: a host computer, an MCU controller, a voltage-controlled DC output power drive circuit, a noise processing module, and a TEC Module and temperature measurement module; among them, the host computer, MCU controller, voltage-controlled DC output power drive circuit, noise processing module and TEC module are connected in sequence; one end of the temperature measurement module is connected to the TEC module, and the other end is connected to the MCU controller.

In the embodiment of the present invention, the host computer may be composed of a computer and programming control software, which realizes data communication between the host computer and the MCU control through the communication interface module inside the MCU controller. Exemplarily, the built-in programming software of the upper computer can be realized by VC, VC++, VB, matlab or Labview.

In the embodiment of the present invention, the MCU controller includes, as shown in Figure 2, a PID algorithm module, a communication interface module, a DAC, and an SPI interface; wherein, the communication interface module realizes the data communication between the MCU controller and the upper computer, and the SPI interface Realize the data communication between the MCU controller and the temperature measurement module. The PID algorithm module performs digital PID calculation according to the target temperature data received by the communication interface module and the temperature monitoring data received by the SPI interface to obtain the required output power value; the DAC calculates according to the PID algorithm module output a power control voltage to the voltage-controlled DC output power drive circuit.

In the embodiment of the present invention, the MCU controller may be FPGA, CPLD, single-chip microcomputer, ARM or DSP. The communication interface module can be a serial port, a USB interface, a PCI bus, a WIFI interface, a Bluetooth interface, or a network interface.

Exemplarily, the programming software of the upper computer can use VC++, the interface between the upper computer and the MCU controller uses the RS232 serial interface, and the temperature control index parameters (target temperature), PID parameters, etc. are sent to the MCU controller through the RS232 serial interface At the same time, information such as temperature, TEC voltage and current monitoring is obtained from the MCU controller and displayed.

Exemplarily, a single-chip microcomputer STM32F103 can be used as the MCU controller. The MCU integrates the RS232 serial communication module and 12bit DAC module, and realizes the configuration and temperature data acquisition of the ADS1248 chip in the temperature measurement module through the SPI interface. According to the temperature index parameters set by the host computer, PID parameters and the temperature data read from the temperature measurement module, the MCU performs real-time digital PID calculations through the PID algorithm module, and the calculation results are converted into control voltage-controlled DC output power drive circuits. The voltage value is generated by the internal 12bit DAC module to output Vref.

In the embodiment of the present invention, the voltage-controlled DC output power drive circuit includes: a DC-DC controller and its peripheral MOSFETs and inductors and capacitors; the DC-DC controller has control voltage input and feedback voltage input pins, and the internal through The comparison between the control voltage and the feedback voltage dynamically adjusts the duty cycle of the PWM signal controlling the external MOSFET, and the output of the MOSFET is converted into a DC signal with a certain ripple through the preset inductance and capacitance; and then the output DC signal is fed back to the DC- The feedback voltage input pin of the DC controller realizes the precise follow-up of the output voltage to the input control voltage, and is not affected by factors such as temperature drift and load change.

At present, there are DC-DC controller chips that integrate this voltage comparison and automatically and dynamically adjust the PWM signal, such as TPS40056 of TI Company.

Exemplarily, the principle of the voltage-controlled DC output power drive circuit is shown in Figure 3, which includes: a DC-DC controller, two external N-channel MOSFETs Q1, Q2, and inductors and capacitors L1, C1, to achieve an output with A DC power drive signal Vout with a certain ripple. At the same time, Vout generates a feedback voltage signal Vfb through the voltage division of the proportional resistor network R1 and R2, enters the input terminal of the DC-DC controller, compares it with the control voltage Vref output by the MCU controller, dynamically adjusts and maintains the DC output The voltage of the power drive signal Vout is stable.

The output drive capability of the voltage-controlled DC output power drive circuit is determined by Vin, MOSFET Q1 and conversion efficiency of the DC-DC controller. In this implementation example, Vin can be powered by 24V. For MOSFET Q1, IRFZ44Z with a conduction resistance of 13.9 milliohms and a maximum conduction current of 51A is selected. After testing, the drive circuit can operate at a Vout of 20V and an output current of 6A, that is, the output power In the case of 120W, it can work stably, and the temperature of the MOSFET will not be too high. In addition, after the output drive signal Vout is filtered by the common mode noise and differential mode noise of the noise processing module, the tested noise is lower than 1mVrms, and the noise interference to the detector and other electronic systems is minimal.

In the embodiment of the present invention, the noise processing module includes: a common-mode inductor and an LC filter network connected in sequence; wherein, the common-mode inductor is used to filter out the common-mode noise in the output signal of the voltage-controlled DC output power drive circuit, and the LC The type filter network is used to filter the differential mode noise in the output signal of the voltage-controlled DC output power drive circuit. With proper selection, the common mode inductor and the LC type filter network can pass relatively large voltage and current, and filter out the noise components in the output signal of the drive circuit very well.

In the embodiment of the present invention, the TEC module is placed in a closed or vacuum chamber, the cold end cools the target detector, and the hot end dissipates heat through a radiator, air cooling or water cooling.

In the embodiment of the present invention, the temperature measurement module includes: a temperature sensor and a temperature measurement circuit connected in sequence; wherein: the temperature sensor is a resistive temperature sensor, a thermocouple or a thermistor; the temperature measurement circuit is a bridge temperature measurement Circuit, constant current source temperature measurement circuit or integrated temperature measurement chip. Exemplarily, a low power consumption, highly integrated 24-bit temperature measurement A/D conversion chip ADS1248 can be used as a high-precision temperature measurement circuit to communicate with the MCU controller through the SPI interface.

The device provided by the embodiment of the present invention adopts a digital PID control scheme, which can avoid the problems of cumbersome circuit parameters and complex and time-consuming debugging of the analog PID control scheme, and effectively reduce the circuit debugging cycle and difficulty; at the same time, through a voltage feedback control The voltage-controlled DC output power drive circuit generates a DC drive voltage signal, and controls the voltage-controlled DC output power drive circuit through the control level signal. The output DC drive signal has very low noise after filtering, which is harmful to the system. Other sensitive circuits are not easily affected, especially suitable for cooling systems of infrared detectors, scientific grade CCD detectors or sCMOS detectors.

Another embodiment of the present invention also provides a high-power low-interference driving method for a thermoelectric cooler, which is implemented based on the device provided in the foregoing embodiment, and its main process is as follows:

The upper computer sends the target temperature data, PID parameters and start working instructions to the MCU controller, and obtains and displays the temperature data sent by the temperature measurement module to the TEC module of the MCU controller;

According to the target temperature set by the host computer and the cooling temperature of the TEC module detected by the temperature measurement module, the MCU controller implements the PID algorithm on-chip, calculates the output power value according to the result of the PID algorithm, and uses this power value output a power control voltage;

The voltage-controlled DC output power drive circuit with input following function follows the power control voltage output by the MCU controller, outputs a driving voltage signal whose voltage is proportional to the input reference voltage, and then filters it through the noise processing module as a low-noise The driving signal directly drives the TEC module;

The temperature change of the TEC module is collected by the temperature measurement module and fed back to the MCU controller. The MCU controller repeats the PID operation at a certain frequency, and continuously adjusts the control voltage signal according to the PID operation result, and then controls and drives the TEC. The power of the module brings the cooling temperature of the TEC module to the target temperature.

In addition, each device involved in the method embodiment has been introduced in detail in the foregoing device embodiment, and the functions and structures of related devices can be referred to the foregoing device embodiment, so details are not repeated here.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person familiar with the technical field can easily conceive of changes or changes within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (8)

1. A high-power low-interference driving device for a thermoelectric cooler, characterized in that it comprises: a host computer, an MCU controller, a voltage-controlled DC output power drive circuit, a noise processing module, a TEC module and a temperature measurement module; wherein , the host computer, MCU controller, voltage-controlled DC output power drive circuit, noise processing module and TEC module are connected in sequence; one end of the temperature measurement module is connected to the TEC module, and the other end is connected to the MCU controller. 2. A high-power low-interference driving device for a thermoelectric refrigerator according to claim 1, wherein the host computer and the MCU controller communicate with each other through a serial port, a USB interface, a PCI bus, a WIFI interface, or a Bluetooth interface. , or network interface for data communication. 3. A high-power low-interference driving device for a thermoelectric cooler according to claim 1, wherein the MCU controller includes: a PID algorithm module, a communication interface module, a DAC and an SPI interface; wherein, The communication interface module realizes the data communication between the MCU controller and the upper computer, and the SPI interface realizes the data communication between the MCU controller and the temperature measurement module. Digital PID calculation to obtain the required output power value; DAC outputs a power control voltage to the voltage-controlled DC output power drive circuit according to the power value calculated by the PID algorithm module. 4. A high-power low-interference driving device for a thermoelectric cooler according to claim 1, wherein the voltage-controlled DC output power driving circuit comprises: a DC-DC controller and its peripheral MOSFETs and Inductance and capacitance; the DC-DC controller has control voltage input and feedback voltage input pins, and internally compares the control voltage and feedback voltage to dynamically adjust the duty cycle of the PWM signal controlling the external MOSFET, and the output of the MOSFET is preset The inductance and capacitance are converted into a DC signal with a certain ripple; and then the output DC signal is fed back to the feedback voltage input pin of the DC-DC controller to realize the precise follow-up of the output voltage to the input control voltage. 5. A high-power low-interference driving device for a thermoelectric cooler according to claim 1, wherein the noise processing module comprises: a common-mode inductor and an LC-type filter network connected in sequence; wherein, the common-mode The mode inductor is used to filter the common mode noise in the output signal of the voltage-controlled DC output power drive circuit, and the LC filter network is used to filter the differential mode noise in the output signal of the voltage-controlled DC output power drive circuit. 6. A high-power low-interference driving device for a thermoelectric cooler according to claim 1, wherein the TEC module is placed in a closed or vacuum cavity, the cold end cools the target detector, and the thermal The end dissipates heat through radiators, air cooling or water cooling. 7. A high-power low-interference driving device for a thermoelectric refrigerator according to claim 1, wherein the temperature measurement module includes: a temperature sensor and a temperature measurement circuit connected in sequence; wherein: the temperature The sensor is a resistive temperature sensor, a thermocouple or a thermistor; the temperature measuring circuit is a bridge temperature measuring circuit, a constant current source temperature measuring circuit or an integrated temperature measuring chip. 8. A high-power low-interference driving method for a thermoelectric cooler, characterized in that, based on the device according to any one of claims 1-7, the process is as follows: The upper computer sends the target temperature data, PID parameters and start working instructions to the MCU controller, and obtains and displays the temperature data sent by the temperature measurement module to the TEC module of the MCU controller; According to the target temperature set by the host computer and the cooling temperature of the TEC module detected by the temperature measurement module, the MCU controller implements the PID algorithm on-chip, calculates the output power value according to the result of the PID algorithm, and uses this power value output a power control voltage; The voltage-controlled DC output power drive circuit with input following function follows the power control voltage output by the MCU controller, outputs a driving voltage signal whose voltage is proportional to the input reference voltage, and then filters it through the noise processing module as a low-noise The driving signal directly drives the TEC module; The temperature change of the TEC module is collected by the temperature measurement module and fed back to the MCU controller. The MCU controller repeats the PID operation at a certain frequency, and continuously adjusts the control voltage signal according to the PID operation result, and then controls and drives the TEC. The power of the module brings the cooling temperature of the TEC module to the target temperature.