Method And Research Of High Voltage Detection Based On Manchester Code And Δ—Σ Modulation

High-voltage inverters are widely used in today’s society,and many industries cannot do without the inverter system.The most important parameter of the high-voltage inverter is the bus voltage,which is the part of the inverter that needs to be strictly controlled.The bus voltage is related to the normal operation of power devices and even the inverter itself.At present,there are many bus voltage detection schemes on the market,but there are still some deficiencies in achieving high performance and reducing risk.In this thesis,the background of high-voltage inverter is introduced,and the damage of over-voltage and under-voltage to the inverter are analyzed,and a bus voltage detection system based on Manchester codec and delta-sigma modulation is proposed.The design is divided into two parts:the medium voltage conversion module and the data processing module.The medium voltage conversion module divides the ±DC 2500V bus voltage by a resistor to obtain a±DC 2V voltage signal.The system corrected signal by AD5172 digital potentiometer and the second-order high-precision ADC chip ADS 1202 is used to Manchester coding and delta-sigma modulation.By mainly using FPGA technology to perform Manchester decoding and Δ—Σdemodulation processing on the signal,the data processing module restores the original voltage signal to 16-bit data,which will be read by PIC single-chip microcomputer and output to the display screen.In addition,in order to achieve electrical isolation between high voltage and low voltage,and to ensure the safety of signal transmission and system operation,optical fiber transmission is adopted as the communication method between the medium voltage conversion module and the data processing module.In this thesis,a bus voltage detection system based on Manchester codec and Δ—Σ modulation is designed.An all-digital phase-locked loop(PLL)is designed to provide synchronous clock for Manchester decoding to ensure signal integrity.In addition,a Sinc3 filter is designed to extract and denoise the data,which improves the anti-jamming and accuracy of the signal.Finaly,the proposed algorithm is simulated and tested by Matlab software and ISE software of Xilinx Company and finally applied to bus voltage detection system.The detection system is currently made into test tooling.It has been tested on the 3300V mine flameproof and intrinsically safe high-voltage inverter of Huaxia TianXin Intelligent Co.Ltd.Experiments show that the bus voltage is updated once every 1 s,achieving the purpose of detecting the bus voltage.Later,it will be applied to the high-voltage inverter by improving the process.