Research And Design Of Turn-to-turn Insulation Test Equipment For Pole Coil Of Large Electric Machine

The turn-to-turn insulation test is an approval test for pole coil of large electrical machine. It is an important part to improve the product reliability of magnetic coil. The current corresponding national standards were carried out on the coil turn-to-turn insulation test also. This thesis is aimed to meet the actual needs of the equipment with higher test voltage level for the turn-to-turn insulation. By referring a lot of literature and combining with previous experience, the pole coil turn-to-turn insulation test technology is studied, and a pole coil turn-to-turn insulation test equipment was designed. The main research works in the thesis are as follows:Firstly, an overview for different pole coil turn-to-turn insulation test technologies was presented, and the technology development status was introduced. The pole coil turn-to-turn insulation test methods with higher frequency were analyzed in detail. The producing method of test voltage waveform for high frequency magnetic coil turn insulation test using inverter bridge based on power electronic switch IGBT was proposed, and the series resonance test method was confirmed through the Orcad / Pspice circuit simulation analysis. The main circuit of the pole coil turn-to-turn insulation test equipment was designed, and its element parameters were selected through circuit simulation analysis.Secondly, the control and display systems for the pole coil turn-to-turn insulation test equipment were designed using high-voltage test techniques, power electronics and microprocessor technology, including the signal detecting system based on MCU 51, the full inverter bridge controller based on M57962, protection system based on relay interlocking technology, and signal display system, which made the test equipment can realize the functions of voltage adjusting, frequency adjusting, inverter protection, and voltage & current display.Thirdly, a low-voltage small-capacity test platform was built, the model confirmatory experiments for design scheme proposed in the thesis was carried out, and the test waveforms were analyzed. Experimental results showed that the design theory of the test equipment was valid, and it can meet the actual requirements.