High performance Peltier controllers and related products. The use of peltier elements in amateur radio designs
Greetings, banggood reader, astrologers have announced the Peltier week, so the review will focus on one interesting application of this contraption. You are welcome under CUT.
Let's start with educational program
As Wikipedia says, "The Peltier element is a thermoelectric converter, the principle of operation of which is based on the Peltier effect - the occurrence of a temperature difference when an electric current flows." I am sure that after this phrase it did not become clearer).
Ok, let's try differently. Imagine a specific aquarium consisting of two types of zones. In the first zone of the aquarium, the fish swim quickly in the second slowly. Let's also imagine blades spinning in the water at the boundaries of the zones. The rules are as follows 1) the fish swims to another zone only when its speed matches the speed set for the zone. 2) when crossing the boundaries of the zone, the fish can interact with the blades to increase or decrease its speed. Now imagine several zones arranged in series. (higher speed zones will be called 3+ with low 3-) The fish is in 3+ it wants to go to 3- it interacts with the blade at the border and starts to swim more slowly, while the blades (at the border of Z+/3-) start spinning faster. Next, the fish wants to move to the next Z+ zone, it needs to accelerate, it interacts with the blade at the Z-/Z+ border and accelerates, while the blade starts spinning more slowly. Then everything repeats. It can be seen that some blades will slow down and others will accelerate. The Peltier element works on a similar principle. Instead of fish, there are electrons instead of the speed of fish, the energy of electrons in semiconductors. When current flows through the contact of 2 semiconductors, the electron must acquire energy in order to move to a higher energy zone of another semiconductor. When this energy is absorbed, the contact point of the semiconductors is cooled. When the current flows in the opposite direction, the contact point of the semiconductors is heated, 
At the same time, the greater the current, the higher the effect of energy transfer, the energy is transferred (and not magically disappears) from the “cold” side to the “hot”, so the Peltier element is able to cool objects to a temperature below room temperature (in other words, it is a semiconductor heat pump). If your task is simply to remove heat from the transistor processor, etc. the use of the Peltier element is unprofitable. You will need a Radiator capable of transferring heat from the cooled object to the environment + the heat generated during the operation of the Peltier element. I think the theory is over, you can move on.
Let's see what the review sponsor thinks 13.90 greens looks like. 
The module is a kind of 5-level sandwich, it consists of a pair of radiators and fans and the Peltier element itself. 
The larger fan is for heat dissipation. With the application of force, it can be removed without unscrewing the screws. 
The most ordinary fan (Power supply 12V, size 90mm) is covered with a grill, initially the fan is set to exhaust air. 
On the opposite side is a small fan (Power supply 12V size 40mm) 
The kid is screwed on the conscience 
Let's look at the radiators 
Large radiator size 100mm*120mm height 20mm 
Small radiator 40mm*40mm height 20mm. The radiators are fastened with two screws, threads are cut in the small radiator. When removing the radiator, thermal paste was found, which is good, but you can see that there is underpressure. 
Contact with a large radiator cannot be called ideal either. 
The main conclusion is that if you want to squeeze the maximum out of this module, be sure to look under the radiators. And if you erase the thermal paste, you can see that an element is installed here TEC1-12705(size 40mm * 40mm * 4mm) although the more powerful TEC1-12706 is declared. Manual for TEC1-12705 
Let's remove the small radiator and try to start the module by measuring the temperatures of the "warm" and "cold" sides. 
The temperature of the "cold" side is -16.1 "hot" 37.5 delta 53.6. current consumption at 12V was 4.2A. 
The Peltier element entered the mode after 90 s.
And now the fun part.
We find a metal and shiny plate and make a hole in it for the thermocouple. 
We put thermal paste and install a thermocouple 
Next, we make a narrowly directed photodetector and a photodiode from black paper and conventional components 
We assemble the finished device, remembering the rule "the angle of incidence is equal to the angle of reflection" 
Who guessed what it is? This is a device (well, more precisely, a model for demonstrating the principle of operation) for determining the dew point temperature / relative humidity of the air. It works as follows: the IR LED shines into the reflective plate, after reflection, the light from the IR LED enters the IR photodiode. A voltage signal is taken from the reverse-biased IR photodiode. When the plate is cooled to the dew point temperature, condensate begins to collect on it, the intensity of the reflected radiation decreases, and the signal on the photodiode changes. By recording the temperature of the plate and the ambient air, the relative humidity can be found. For work I used Brymen BM869 (with self-made cable and software) and Uni-t UT61E 
Below is the result 
The red graph is the temperature of the plate, the blue graph is the signal from the photodiode. We will consider the moment when the voltage from the photodiode has changed by half of the total voltage change is the moment of condensation. Based on the set conditions, the measured dew point temperature in the room is +9C. The ambient air temperature is 26.7 (it was not displayed on the graphs because it was unchanged). graph). Next, I used an online calculator to convert humidity to dew point temperature 
The result of converting humidity from HTU21 to dew point temperature coincided with the directly measured dew point temperature. This means that if you determine the dew point using the method described above, and then do the recalculation, then you can accurately determine the humidity (Well, of course, if you do everything in an adult way). This method is called the chilled mirror method, and hygrometers based on this principle are called condensation hygrometers. I hope you enjoyed the review and learned something new for yourself. Thank you all for your attention.
The product was provided for writing a review by the store. The review is published in accordance with clause 18 of the Site Rules.
I plan to buy +13 Add to favorites Liked the review +59 +108The Peltier controller is a semiconductor device designed to cool or heat a thermally stabilized object, depending on the direction of the flowing current. Using a Peltier controller allows you to precisely control the temperature of an object by controlling the direction and magnitude of the current.
We manufacture a wide range of Peltier controllers.
The main features of the TECA1-xV-xV-D series are: high efficiency and current stability, compact dimensions. The maximum current is 2.5A. This series is often used for temperature control in laser systems.
TEC5V4A-D is almost identical to the TECA1-xV-xV-D described above, except for a higher maximum output current of 4A instead of 2.5A.
The TEC5V6A-D controller has the same pinout as the previous 2 controllers.
ATEC24V10A-D controller is under development. This series will work with high input voltage, high output current, high energy efficiency and small size.
ATFC105D is a digital peltier controller. It comes with a keypad and digital display, can be field programmed, and accepts high input voltage and high output current.
Most of these thermoelectric cooler controllers are well compatible with our thermoelectric modules, thermistors and heat transfer materials.
Efficiency: 90%
Maximum output current: 2.5A
Maximum Output Voltage: Externally adjustable from 0V to Vps -Iout * 0.1
Supply voltage: 3.1V to 3.5V or 4.75 to 5.25V (Specify 3.3V or 5V when ordering)
Set temperature. control voltage: 0 to 3.0Vで
Package: DIP Package
Buy now In stock: 15
(In developing)
This is a compact high efficiency electronic module designed to control TECs (Thermoelectric Modules) to control the temperature of the target within a pre-set temperature window. is within the set window, and the TEC controller is not turned on, only sometimes, the target temperature is out of the preset window and the TEC controller is turned on to bring the set temperature back to be within the limits.
Production time: 4 weeks
(In developing)
High output voltage: 24V
High output current: 10A
High efficiency: >96%
High temperature stability:<0.01C
Programmable current limit
Full shielding
Compact size: 38.8 x 34.5 x 7.5 (mm)
DIP and SMT packages available
100% Lead Free (Pb) - and RoHS Compliant
Production time: 4 weeks
Distinctive features:
- Direct control in current mode prevents current surges in thermoelectric (TEC) modules
- Embedded Power MOSFETs
- High efficiency, impulse design
- Ripple limiting function for noise reduction
- No dead zone or yaw in low output current modes
- Adjustable voltage limit TEC module
- Separate control of heating and cooling current limits
- ITEC output provides current monitoring of the TEC module
- ION with an error of 1%
- Conversion frequency 500 kHz/ 1 MHz
Output current 3A (MAX1968)
Output current 6A (MAX1969) - Thermally optimized housing TSSOP-EP
Areas of use:
- Fiber laser modules
- Temperature control systems for laser diodes in WDM, DWDM systems (wavelength division multiplexing - wavelength division multiplexing, dense wavelength division multiplexing - spectral density division multiplexing)
- Network fiber optic equipment
- Optical amplifiers EDFA (erbium-doped fiber amplifier - fiber amplifier doped with erbium)
- Telecommunication fiber optic interfaces
- Automatic test equipment
- Equipment for biotechnological laboratories
Typical switching circuit:
Pin Arrangement:
Description:
The MAX1968/MAX1969 are highly integrated and cost effective, high performance pulse mode drivers for Peltier thermoelectric (cooling) TEC modules. Both ICs provide direct current control to eliminate current surges in TEC modules. Built-in FETs reduce the number of connected external elements, and at the same time, increase control efficiency. The 500 kHz/1 MHz control mode and unique ripple suppression system reduce component size and noise levels.
The MAX1968 is single-powered and provides a bipolar 3A control output by connecting a TEC module between the outputs of two synchronous buck regulators. Bipolar mode allows temperature control without dead zones or other non-linearities at low load currents. This implementation of the control scheme ensures that there is no "yaw" when the system state approaches a threshold control point requiring a small level of cooling or heating of the system. The analog control signal precisely sets the TEC current of the module. The MAX1969 provides a unipolar control signal up to 6A. Fault tolerance is optimized by setting adjustable thresholds for both module voltage and current, with separate heating and cooling current limits. The analog output also monitors the module's TEC current.
I first came across Peltier elements (hereinafter referred to as EP) several years ago when I was developing a cooling device for an aquarium. Today, EPs have become even more affordable (the cost is from 500 rubles), the scope of their application has expanded significantly.
For example, free-coolers (water coolers, water dispensers, dispensers), which can be found in any office, as well as in some private homes, are water-to-air heat exchangers that provide water cooling by means of ambient air passing through the heat exchanger plates, with using axial fans, are unthinkable without EP.
The EA in the form of a square 4×4 cm (Fig. 5.12) is fixed between the cooling radiator and the body of the water tank with the help of special thermal paste and coupling screws, the “cold” surface to the tank.
Fig 5.12 Appearance of the Peltier element of the brand TES-1-1208
Other EAs of the same size are also widely used, for example CP1.4-127-045L. The main parameter of the EP is the maximum power.
Reliable mechanical contact between the heat exchanger and the radiator is important, therefore, thermal lubrication is applied to both sides of the EA. If there is no special thermal paste, you can successfully use pharmacological agents bought inexpensively at a regular pharmacy, for example, Lassari paste or salicylic-zinc paste.
Since the maximum temperature on the “hot” side of the EA reaches +80 °C (and for Supercool high-temperature coolers the maximum temperature is +150 °C), it is important that the EA is cooled properly.
The "hot" surface of the EA is facing the radiator, on the other side of which a cooling fan is installed (the air flow is directed from the radiator to the outside). The fan and the electric converter are connected to a 12-14 V power supply (consisting of a step-down transformer, a diode rectifier and a smoothing oxide capacitor) in accordance with the polarity; EP is permanent, and the fan is controlled by an electronic device, which is based on a comparator and a temperature sensor connected to the water tank. As soon as the water temperature in the tank rises above +5 °C, the fan automatically turns on and cooling begins. According to the passport data of the YH-110 desktop cooler, water is cooled to +5 °С. The ripple of the power supply should not exceed 5%, otherwise the efficiency of the EA is degraded.
The operation of the EP is based on the effect discovered by the French watchmaker Jean Peltier. In 1834, during the experiment, Peltier discovered that when a direct electric current flows in a circuit consisting of dissimilar conductors, heat is absorbed or released at the contacts (junctions) of the conductors, depending on the direction of the current. The amount of heat is proportional to the current passing through the contact of the conductors (Fig. 5.13).
When a direct electric current passes through the electric field, a temperature difference arises (dT = Th - Tc) between its sides: one plate (cold) is cooled, and the other (hot) is heated.
If you apply a temperature difference to the EA, the module will give an electric current. This is confirmed by the experiments described in Table. 1 and a note to it. Based on this effect, in the future, it is possible to create a portable source of electricity.
The Peltier effect is most pronounced on the contacts of semiconductors with different types of conductivity (p- or p-). The explanation of the Peltier effect lies in the interaction of conduction electrons, slowed down or accelerated in the contact potential of the pn junction, with thermal vibrations of atoms in the semiconductor array. As a result, depending on the direction of electron movement and, accordingly, the current, heating (Th) or cooling (Tc) of the semiconductor section directly adjacent to the junction (p-p- or p-p junction) occurs.
The Peltier effect underlies the operation of a thermoelectric module (TEM). A single element of the TEM is a thermocouple consisting of one p-type conductor (leg) and one n-type conductor. When several such thermocouples are connected in series, the heat (Qc) absorbed at the p-p contact is released at the p-p type contact (Qh). A thermoelectric module is a set of thermocouples connected in series. Thermocouples are placed between two ceramic plates. The branches are soldered onto copper conductive pads (shanks), which are attached to heat-conducting aluminum oxide ceramics; this material is resistant to high temperatures of several hundred degrees Celsius. The case of the electric converter is made of bismuth telluride, in which special additives (selenium, antimony) are added to obtain the required type and conductivity parameters.
The number of thermocouples in different EAs varies widely - from a few to several hundreds, which makes it possible to create thermocouples with a cooling power from tenths to hundreds of watts.
The maximum temperature difference between the sides of the EA (dTmax, °C) can reach more than 80 °C. Qmax (W) - cooling capacity at current I = Imax and temperature difference dT = Th - Tc = 0, provided that all the heat entering the cold side of the module is instantly and without loss transferred to the hot side, and the temperature of the hot side Th is maintained at 27 °C (300 K).
Rice. 5.13. Illustration of the transformation of the temperature affecting the EA into electric current
It is recommended to apply a constant voltage to the outputs of the EA. A slightly higher (relative to that indicated on the module) applied voltage makes it possible to achieve a large cooling capacity without reducing the coefficient of performance, which is important when cooling computer processors. The power consumption will increase proportionally.
In addition to water cooling, EP is actively used as an air-to-air cooler, for example, for cooling microcircuit cases and printed circuit boards. Cooling of processors in computers is just one example of the use of EP.
If we consider liquid (water) cooling, then EP is also involved in such a device (see Fig. 5.14).
Standard single-stage modules up to 70 W (12 V) and 172 W (24 V) maximum power. The designations (marking) of the modules are deciphered as follows; the first number is the number of thermocouples in the module; the second is the width of the sides of the branch in mm; the third is the height of the branch in mm. For example, TV-127-1.4-1.5.
The EA modules are hermetically sealed, which makes it possible to use them even in water (see Table 1 for a description of the experiment in boiling water), the EA ceramic surface is polished. Black (-) and red (+) wires are soldered to the lamellas (pins). If the EA is positioned with the leads towards itself so that the black wire (Fig. 1) is on the left and the red wire is on the right, the “cold” side will be on top and the “hot” side on the bottom. The marking is applied, as a rule, on the hot side.
Rice. 5.14. Fluid cooler
Cooling/heating of laser components, fiber optics, semiconductors, laboratory instruments, medical equipment, electronic chassis, floppy and hard disks, food and beverages. EA and modules based on them can be used in the thermal cycling mode: alternate the cooling mode with heating - using the switch for changing the polarity of the applied voltage. This process of impulse control can be automated and “entrusted” to electronics. The degree of cooling is proportional to the magnitude of the current passing through the EA, which allows you to control the temperature of the cooled object with high accuracy.
At normal (room) exposure temperature, the surfaces of both sides of the EP have a temperature of +8 ... +10 °С (much lower than room temperature, for which we will take +19 °С in this experiment).
Consider the change in the resistance of the EA in different modes (the M830 tester is connected to the EA outputs (lamellas) in the resistance measurement mode). The results of the study are summarized in table. 5.1.
Scope of EP
When exposed to a temperature greater than the constant room temperature, on one side (marked) of the EA, its resistance decreases, on the reverse side it increases proportionally. The simplest example for illustration is touching the edge of the palm to the surface of the EA, described in experiments 2 and 3 of Table. 5.1.
The frequencies 7296.0 kHz, 7165.5 kHz, 18157.5 kHz, 14342.5 kHz in USB mode and 10117.5 kHz in CW are used by shortwaves mainly for foot expeditions.
Literature: Kashkarov A.P. Electronic devices for coziness and comfort.