Research On Voltage Transformer Of Wide Frequency For Motor Train Unit

The traditional voltage transformer is used in power frequency. Measurement results become less accurate with high frequency and it can’t provide the frequency parameter. Pulling motor’s frequency band is wide in motor train unit. We can’t adopt the traditional voltage transformer for measuring. The designing need to consider the core of magnetic flux density and precision. we designed a kind of broadband voltage transformer measuring system suitable for traction system of CRH1. The iron core used microcrystalline with low output. Through a simple conversion the output voltage could be convenient to computer processing. It could export voltage and frequency parameters and it could communicate with PC and the iron core loss was low with high precision.First, voltage transformer’s basic principle, basic parameters, the error sources and so on were described in this paper. Then Maxwell Field Equations, basic principle, basic steps and qualities of Finite Element Analysis were described. This paper analysed the transient field principles. Secondly, This paper analysed iron core loss in50Hz and100Hz with silicon steel shee and choose microcrystalline alloy as iron core. Permeability, saturation magnetic induction, price and other parameters were compared in soft magnetic materials commonly used. The paper put forward an energy saving low power voltage transformer suitable for vehicle condition with high precision and quick response characteristics. Then the paper finished the calculation of relevant parameters. The paper observed magnetic flux, field current, nephogram of magnetic flux density, magnetic flux density image, induced voltage for primary side and secondary side and other parameters. Magnetic flux was larger with no-load switching and it produced several times field current with short time to return to normal. The voltage was small with moderate simulation difficulty and the waveform displays well. Finally, The article accomplished the output voltage processing. It selected AT89C51as processor and made voltage sampling. It designed sampling circuit, power supply circuit, display circuit and so on. It made simulation analysis for the peripheral circuit. At the same time the system was a strong electromagnetic environment, the article analyzes the interference source and gave the anti interference measures. In this paper, The finite element analysis, computer processing technology were combined. It designed a special broadband voltage transformer for the traction system of motor train unit and it was beneficial to integration and intelligence. It provided reference information for localization of broadband voltage transformer for motor train unit.