CN116560433A - Method and system for integrally realizing temperature measurement and control by adopting diode - Google Patents

Abstract

The present invention provides a method and system for realizing temperature measurement and control by adopting diodes. The system includes a diode voltage and current acquisition circuit, a temperature calculation module, a control circuit, a current source circuit and a series diode connected in sequence. The series diode consists of Multiple diodes are connected in series. The beneficial effects of the present invention are: the present invention adopts the diode as the temperature actuator to solve the problem that the traditional actuator and the controlled object are not tightly bonded, so that the temperature control effect is better, and the diode is cheap and safe. The diode realizes the integration of temperature measurement and control, and is suitable for various systems that need to control temperature.

Description

Method and system for realizing temperature measurement and control by adopting diode integration

technical field

The invention relates to the technical field of temperature control, in particular to a method and a system for realizing temperature measurement and control by integrating diodes.

Background technique

Temperature is a very important parameter in the industry, and the demand for temperature control in the industrial field is also increasing. Especially when it comes to some precision components that are greatly affected by temperature, the influence of temperature will reduce their accuracy and even make them unusable. These precision components need to control and stabilize the temperature so that they can work normally. The current temperature control technology has high requirements for actuators, but some actuators still have potential safety hazards. Traditional temperature control actuators mostly use resistance heating. Resistance heating is widely used, but it has the characteristics of large overshoot, and the resistance changes with temperature, which is not conducive to temperature control. At the same time, the resistance is easy to expose the metal wire on the outer surface, which brings harm. In addition, factors such as the use safety of the temperature sensor of the temperature control system have brought great challenges to the temperature control system. The current and voltage characteristics of the diode are related to temperature, and can be used as a sensor for accurately measuring temperature. Patent CN 104820179A proposes a PN junction temperature measurement method that eliminates the influence of series resistance and has nothing to do with reverse saturation current. This method eliminates both the diode reverse saturation current and the influence of series resistance through three constant currents. The accuracy of this method is higher. The method for measuring the diode junction temperature in the patent CN 113588106A considers the factor that the ideality factor changes with temperature, and adopts a calculation method for compensating the intercept difference of the diode forward voltage and temperature (VF-T) curve at absolute zero, eliminating the ideal Effect of factor changes on temperature measurements.

The above patents (CN104820179A, CN 113588106A) all use diodes as temperature sensors for measurement. At present, there is a lack of technical solutions for using diodes as actuators and sensors at the same time, which cannot meet the needs of users.

Contents of the invention

The invention provides a system that adopts diodes to realize temperature measurement and control, including a diode voltage and current acquisition circuit, a temperature calculation module, a control circuit, a current source circuit and a series diode connected in sequence, and the series diode is composed of a plurality of diodes connected in series Composition, the diode voltage and current acquisition circuit is used to measure the voltage and current of the diodes in series, the diode voltage and current acquisition circuit inputs the collected signals of the voltage and current of the series diodes into the temperature calculation module, and the temperature calculation module is based on The received signal calculates the temperature of the series diode, and the temperature calculation module transmits the temperature of the series diode to the control circuit, and the control circuit compares the received temperature with the preset temperature, and according to the result of the temperature comparison, the The control circuit adjusts the voltage of the output control, the control circuit inputs the voltage signal into the current source circuit, the current source circuit adjusts the output current according to the received voltage, and the current source circuit transmits the output current to the series diode.

As a further improvement of the present invention, the control circuit is a PID control circuit.

As a further improvement of the present invention, the system also includes an AD conversion module and a DA conversion module, the AD conversion module is connected between the diode voltage and current acquisition circuit and the temperature calculation module, and the diode voltage and current acquisition circuit will The collected analog signals of the voltage and current of the series diodes are input into the AD conversion module, the AD conversion module converts the analog signals of the voltage and current into digital signals, and the AD conversion module inputs the digital signals into the temperature calculation module, The temperature calculation module calculates the temperature of the series diode according to the received digital signal; the DA conversion module is connected between the PID control circuit and the current source circuit, and the PID control circuit inputs the digital signal of the voltage to the The DA conversion module, the DA conversion module converts the digital signal of the voltage into an analog signal, and the DA conversion module inputs the analog signal of the voltage into the current source circuit.

As a further improvement of the present invention, during operation, the preset temperature is input to the PID control circuit.

The present invention also provides a method for realizing temperature measurement and control by integrating diodes, including the following steps:

Step 1: Determine the area of the device to be controlled, and obtain the number of diodes in series according to the area; input the target temperature into the PID control circuit as the preset temperature;

Step 2: When the temperature needs to be measured, three constant currents are given to calculate the corresponding temperature by measuring the voltage and current of the diodes in series;

Step 3: Comparing the temperature calculated from the measured series diode current and voltage with the preset temperature in the PID control circuit;

Step 4: According to the temperature comparison result, the PID control circuit is used to adjust the output control voltage;

Step 5: the voltage output by the PID control circuit controls the output current of the current source circuit;

Step 6: The current output by the current source circuit causes the series diode to generate heat to control the temperature T, and the change of the temperature T affects the change of the current and voltage of the series diode.

As a further improvement of the present invention, the method also includes step 7,

Step 7: When the series diode reaches the preset temperature value, the PID control circuit controls its output voltage to maintain the preset temperature. If the obtained temperature does not match the preset temperature, continue to adjust the output voltage of the PID to control the current source circuit. current.

The beneficial effects of the present invention are: the present invention adopts the diode as the temperature actuator to solve the problem that the traditional actuator and the controlled object are not tightly bonded, so that the temperature control effect is better, and the diode is low in price and high in safety. The diode realizes the integration of temperature measurement and control, and is suitable for various systems that need to control temperature.

Description of drawings

Fig. 1 is a system schematic diagram of the present invention;

Figure 2a is a schematic diagram of diode voltage and current changing with time;

Figure 2b is a schematic diagram of the temperature change of the diode with time;

Figure 3a is the power supply voltage output diagram without diode temperature control;

Figure 3b is a diagram of the power supply voltage output when the temperature control of the diode is increased.

Detailed ways

According to the PN junction temperature measurement method proposed by the patent CN104820179A that eliminates the influence of series resistance and has nothing to do with the reverse saturation current, ISO is the reverse saturation current of the PN junction, I _b is the current actually flowing through the diode, k is the Boltzmann constant, q is the basic charge constant, T is the absolute temperature, VF is the forward voltage of the PN junction, n is the ideal factor, let the constant Using three currents I _b0 , I _b1 , I _b2 , the series resistance is R _w , let I _b1 = N ₁ I _b0 , I _b2 = N ₂ I _b0 , and the corresponding voltages are V ₀ , V ₁ , V ₂ , then have:

Combine the above formulas (1) and (2) to get rid of the temperature measurement results of _ISO and _Rw :

There is a PN junction inside the diode. When a diode is conducting forward, the current increases as the voltage increases. The characteristic of the diode is that within the normal use range, the voltage across the diode remains almost constant, and the voltage changes little as the current increases. The heat generated by the diode itself comes from the power dissipation when current passes through the diode. When the diode is working normally, its temperature will increase due to the self-heating effect. The resulting temperature is determined by the temperature of the diode, which is determined by the ambient temperature and the forward bias current and voltage flowing through it, satisfying equation (4). In the formula, T _L is the diode temperature, T ₀ is the ambient temperature, I is the forward bias current of the diode, V is the forward bias voltage, and R _th is the thermal resistance. When the diode is working normally, the voltage change range is very small, and the power P is mainly related to the current flowing through the two ends of the diode. This characteristic makes the overshoot in the process of adjusting the current to heat the diode easy to control, and the heating is stable. Diodes are regulated as temperature actuators, reducing overshoot.

T _L =T ₀ +R _th I (4)

The relationship between the conversion of electrical energy into heat energy, the power of the temperature actuator is closely related to the temperature. At this time, the power flowing through the diode satisfies Equation (5). P is the power of the diode. The characteristics of the diode determine that when the adjustment current and voltage change are small, the temperature adjustment is relatively easy, and it is easier to achieve temperature stability and higher accuracy.

P=IV (5)

The power of the resistor is related to the square of the current, which satisfies the formula (6). R is the resistance value. Equation (7) expresses that the power of the MOSFET is related to the square of the voltage. Therefore, compared with the three, the diode is an advantageous temperature actuator due to its own nature.

P=I ² R (6)

P=V ² /R (7)

In the invention, the diode is used as an actuator and a sensor at the same time, and the temperature is obtained and controlled by measuring the current and voltage flowing through the diode.

The current passing through the diode can heat the diode. Due to the small change in the voltage across the diode, the relationship between temperature and current can be easily controlled, and the diode itself can be used as an actuator for temperature control. The method of the invention considers that the diode can be used not only for its heating function but also for its sensing function, without adding other complex actuators and sensors, and increasing the reliability of the temperature control system.

As shown in Figure 1, the present invention discloses a system that adopts a diode to realize temperature measurement and control, including a diode voltage and current acquisition circuit, a temperature calculation module, a control circuit, a current source circuit and a series diode connected in sequence. The diode is composed of a plurality of diodes in series, and the diode voltage and current acquisition circuit is used to measure the voltage and current of the series diode, and the diode voltage and current acquisition circuit inputs the collected signals of the voltage and current of the series diode into the temperature calculation module, The temperature calculation module calculates the temperature of the series diode according to the received signal, the temperature calculation module transmits the temperature of the series diode to the control circuit, and the control circuit compares the received temperature with the preset temperature, according to As a result of the temperature comparison, the control circuit adjusts the voltage of the output control, the control circuit inputs the voltage signal into the current source circuit, the current source circuit adjusts the output current according to the received voltage, and the current source circuit outputs current is delivered to the series diodes.

As a preferred embodiment of the present invention, the control circuit is a PID control circuit, the system also includes an AD conversion module and a DA conversion module, and the AD conversion module is connected between the diode voltage and current acquisition circuit and the temperature calculation module During the period, the diode voltage and current acquisition circuit inputs the analog signals of the voltage and current of the collected series diodes into the AD conversion module, and the AD conversion module converts the analog signals of the voltage and current into digital signals, and the AD conversion module The digital signal is input into the temperature calculation module, and the temperature calculation module calculates the temperature of the series diode according to the received digital signal; the DA conversion module is connected between the PID control circuit and the current source circuit, and the The PID control circuit inputs the digital signal of the voltage into the DA conversion module, the DA conversion module converts the digital signal of the voltage into an analog signal, and the DA conversion module inputs the analog signal of the voltage into the current source circuit.

When working, input the preset temperature in the PID control circuit, and the diode voltage and current acquisition circuit measures the voltage and current of the series diodes. When the temperature needs to be measured to provide temperature feedback, due to the inertia of the temperature, three constant currents are given in a very short time. Without changing the control temperature conditions, the temperature of the corresponding diode is fed back to the PID control circuit after being collected by the AD conversion module, and the output voltage of the DA conversion module is adjusted through the PID to control the output current of the current source circuit. This output current is used to provide current for the series diodes. Through Change the size of the current to adjust the heating temperature of the diodes in series to reach the final target temperature.

The invention also discloses a method for realizing temperature measurement and control by integrating diodes, which includes the following steps:

Step 1: Determine the area of the device to be controlled, and obtain the number of diodes in series according to the area; input the target temperature into the PID control circuit as the preset temperature;

Step 2: When the temperature needs to be measured, three constant currents are given in a very short time. By measuring the voltage and current of the diodes in series, the corresponding temperature is calculated;

Step 3: Comparing the temperature calculated from the measured series diode current and voltage with the preset temperature in the PID control circuit;

Step 4: According to the temperature comparison result, the PID control circuit is used to adjust the output control voltage;

Step 5: the voltage output by the PID control circuit controls the output current of the current source circuit;

Step 6: The current output by the current source circuit causes the series diode to generate heat to control the temperature T, and the change of the temperature T affects the change of the current and voltage of the series diode;

Step 7: When the series diode reaches the preset temperature value, the PID control circuit controls its output voltage to maintain the preset temperature. If the obtained temperature does not match the preset temperature, continue to adjust the output voltage of the PID to control the current source circuit. current.

To illustrate with an example: set the temperature control target to 41°C, and compare the results of resistors, diodes and MOSFETs from the perspective of control effects. It can be seen from the experiment that the resistance is extremely sensitive to the change of the current due to the heating of the resistance through the current, and the change of the current will have a great impact on the temperature. At the same time, the resistance value of the resistance will change with the temperature, which is not conducive to temperature control. The overshoot of resistance heating is large, and the stable temperature fluctuation range is wide. It can be seen from the experiment that the control effect of the diode is relatively stable and there is almost no overshoot, and a good temperature control effect is obtained by connecting the diode in series. Since the diode voltage varies little with current and temperature, the temperature of the diode is almost linear with the current. For MOSFETs, temperature is closely related to changes in both voltage and current. It can be seen from the experiment that the temperature of the MOSFET changes drastically, so it is not suitable for a temperature actuator for temperature control.

We experimented with the relationship between voltage, current, and temperature across a diode. The voltage and current through a diode are known, and each set of current-voltage values corresponds to a specific temperature value. With the temperature change corresponding to the voltage and current changes of each group, the stability of the diode temperature can also be reflected by the current and voltage.

Set the temperature control target temperature to 50°C. From Figure 2a, it can be seen that the voltage change is small and the current change is relatively large. At the beginning of temperature control, the current is the largest, the voltage is also the largest, and the power is the largest at this time. In order to quickly achieve the goal of temperature control, the control process is to save heating time. After the final temperature stabilizes, the current and voltage changes relatively little. This process is shown in Fig. 2b as the temperature stabilizes during regulation.

The ambient temperature change of the power supply will have a great impact on precision devices, thus affecting the stability of voltage output. Applying different temperatures to observe the output stability of the power supply, it can be found that when the ambient temperature of the sensitive components in the power supply ranges from 26°C to 40°C, the change is very obvious, and the average value of the output voltage also changes with the change of temperature, as shown in Figure 3a , the output is very unstable, and the mean value has been increasing with temperature fluctuations. However, after adopting temperature control, as shown in Figure 3b, the temperature is stable at about 50°C. At this time, the voltage output stability is high, and the average value change is small, which is very conducive to the work of the power supply. The applied temperature control has proven to be very effective in stabilizing the power output, which plays an important role in the safety of the equipment.

The beneficial effects of the present invention are as follows:

1. The method of adopting integrated diodes to realize temperature measurement and control proposed by the present invention is applicable to various systems requiring temperature control.

2. The present invention adopts the method of controlling the temperature of the diode, and due to the characteristic that the voltage of the diode changes little, it can be quickly adjusted to the expected temperature without obvious overheating phenomenon.

3. The present invention uses diodes as temperature actuators to solve the problem of loose bonding between traditional actuators and controlled objects, making the temperature control effect better.

4. The present invention proposes to use a diode as a temperature actuator and can measure the voltage and current flowing through the diode to obtain the corresponding temperature without adding an additional temperature sensor.

5. The present invention does not require a traditional temperature actuator, and a common diode is selected as the temperature actuator for temperature control, which is cheap and safe.

6. Diodes are suitable for more scenarios, especially having two diodes in a common cathode diode can also be used as a backup.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deduction or replacement can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (6)

1. A system for integrally realizing temperature measurement and control by adopting a diode is characterized in that: the temperature calculation module calculates the temperature of the serial diode according to the received signal, the temperature calculation module transmits the temperature of the serial diode to the control circuit, the control circuit compares the received temperature with a preset temperature, the control circuit adjusts the voltage of output control according to the result of temperature comparison, the control circuit inputs a voltage signal to the current source circuit, the current source circuit adjusts the output current according to the received voltage, and the current source circuit transmits the output current to the serial diode.

2. The system according to claim 1, wherein: the control circuit is a PID control circuit.

3. The system according to claim 2, wherein: the system also comprises an AD conversion module and a DA conversion module, wherein the AD conversion module is connected between the diode voltage and current acquisition circuit and the temperature calculation module, the diode voltage and current acquisition circuit inputs the acquired analog signals of the voltage and the current of the serial diode into the AD conversion module, the AD conversion module converts the analog signals of the voltage and the current into digital signals, the AD conversion module inputs the digital signals into the temperature calculation module, and the temperature calculation module calculates the temperature of the serial diode according to the received digital signals; the DA conversion module is connected between the PID control circuit and the current source circuit, the PID control circuit inputs a digital signal of the voltage to the DA conversion module, the DA conversion module converts the digital signal of the voltage to an analog signal, and the DA conversion module inputs the analog signal of the voltage to the current source circuit.

4. A system according to claim 3, characterized in that: when the PID control circuit works, the preset temperature is input into the PID control circuit.

5. The method for integrally realizing temperature measurement and control by adopting the diode is characterized by comprising the following steps of:

step 1: determining the area of a device to be controlled, and obtaining the number of diodes connected in series according to the area; inputting the target temperature into a PID control circuit as a preset temperature;

step 2: when the temperature needs to be measured, three sections of constant currents are given, and the corresponding temperature is calculated by measuring the voltage and the current of the diodes connected in series;

step 3: comparing the calculated temperature of the measured current and voltage of the series diode with a preset temperature in the PID control circuit;

step 4: according to the comparison result of the temperature, a PID control circuit is adopted to adjust the voltage of the output control;

step 5: the voltage output by the PID control circuit controls the output current of the current source circuit;

step 6: the current output by the current source circuit enables the series diode to generate heat to control the temperature T, and the change of the temperature T influences the change of the current and the voltage of the series diode.

6. The method according to claim 5, further comprising step 7,

step 7: when the series diode reaches a preset temperature value, the PID control circuit controls the output voltage of the series diode to reach a preset temperature, and if the obtained temperature does not accord with the preset temperature, the PID control circuit continuously adjusts the output voltage to control the current of the current source circuit.