| Cooling unit is the key unit of high-precision recirculating cooling water system.Thermoelectric cooler (TEC) can output refrigerating capacity, making use of ‘PeltierEffect’. And Compared to traditional refrigerating style, thermoelectric cooling hasspecial characteristics, such as non-pollution, non-noise, low-weight, small-volume.TEC is a kind of ideal refrigerating cooler. The cooling unit of high-precisionrecirculating cooling water system is composed of some parallel TEC and it requirehigh refrigeration power and refrigeration precision.TEC is one kind of coolers with the characteristics of low voltage and high current.We can obtain different refrigerating power by changing TEC’s supply voltage. AndTEC’s refrigerating power and cooling precision are relative to TEC driver power,ripple and noise. So it has a great importance to design and manufacture a TEC driverwith the characteristics of high power, low ripple and adjustable output voltage.Firstly, this paper investigated and analyzed the basic circuit structures and outputvoltage adjusting strategies in TEC drivers. After contrasting different circuit structuresand adjusting strategies, the paper selected switching power supply’s full-bridgetopology as TEC driver’s basic circuit structure, and selected the method of changingreference source as TEC driver’s output voltage adjusting strategy.Secondly, According to the demand of high-precision recirculating cooling watersystem and the driving characteristic of TEC, the paper put forward driver’s designtarget, and has designed driver’s overall project, including preceding stage’s DC voltageproducing circuit, full-bridge converter, feedback circuit and assisting functional circuit.Then, the paper designed in detail several key unit circuits, namely EMI filter, snubbercircuit of primary stage of full-bridge converter, LC filter at output port, soft start circuit,in which the paper gave the practical method of component parameters of circuits. Thenthe paper analyzed the principle of magnetic components which was represented byhigh-frequency transformer and output filtering inductor by product method of area.And the paper confirmed several key factors, for example, magnetic core, number ofturns, wire diameter, the style of wire wrapping, and verified the reasonability ofdesigning in theory.Thirdly, the paper constructed the small-signal model of the driver. According tothe theory of automatic control, the paper analyzed the stability of driver system, anddrew out the diagram of open-loop transfer function of driver system. Referencing to thebode diagram, the paper designed the feedback compensation network on the basis ofthree-polar and two zero compensation network, improving the stability of driversystem.At last, the experiment chapter of the paper tested several functional indicators, namely output voltage adjusting range, output linearity, output power, ripple and noise,power efficiency, and frequence response. The results indicated that the driver’scharacteristics with the output voltage adjusting range0~12.5V, control linearity0.33%,ripple and noise65mVPP, power efficiency80.6%, frequence response1.7kHz, can meetthe design demand. |
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