The Design Of Digital Power Supply Based On Electromagnetic Induction

With the development of Smart Grid, there will be more and more Monitoring Terminal used to monitor the real-time operational status parameters of transmission and distribution equipments. For the Monitoring Terminal installed by the high-voltage side, electrical safety should to be considered, and the reliable power supply was the key issues to be solved. For solving this problem, a type of digital power supply based on electromagnetic induction was developed in this paper. It used the Current Transformer (CT) to obtain energy from the high-voltage cable by the way of electromagnetic induction.By selecting a high magnetic saturation point, the Iron-core of CT was always working in non-saturation status during the dynamic current in high-voltage cable. The CT ratio was regulated according the sampling voltage of output by the way of eliciting several taps from the secondary coil of CT. The adaptability of the developed power supply to the dynamic range of high-voltage cable current was more widely than that of the conventional power supply. The problem of heat consumption increased with the current which existing in normal CT supply was also effectively solved. A detailed design of electronic circuits was given in this paper, and the output voltage can be changed by programmer which avoiding changing the hardware.The results indicated that the power supply designed in this paper could output about 500mw for the high-voltage side electronic devices while the cable current changed from 10Ato 1000A. It has some practical value.