Development On LCR Parameter Testing Instrument Based On FPGA

Power equipments'state monitoring and fault diagnosis are related to safe and stable operation of electric power system. LCR, the dielectric loss of electric equipments, the leakage current of MOA, and network parameter and direction current resistance of the perceptual load in transformer are all mandatory measurement items in primary and secondary distribution network. At present, there are different unifunctional measuring instruments. However, several measuring instruments are not only unconveniently carried, but also abraded each other in rough field condition. Portable Multifunction Wide-Range Testing Meter is a research project. It is designed for testing various electric parameters. While with this testing meter, we got all this functions together and it saves money and reduces maintaining time.After looking up and analyzing relevant domestic and oversea documentations, the overall plan of design has been presented, which adopts embedded industrial-control computer as its up-machine, DSP and single-chip microprocessor as its down-machine. Communication between them uses RS-485 Bus.The emphasis of this paper is research on LCR parameter testing instrument that based on FPGA. Hardware circuit is composed of following parts: signal source module, impedance-voltage converter module, digital phase-sensitive demodulator and acquisition module. This paper explains volt-ampere measuring principle based on free-axis and concretely analyse the realization of signal source module based on FPGA. And then, structure and the feature of FPGA device have been introduced. On the basis of chip application goal being given, we analyze the related develop environment and tool. The key technique of impedance-voltage converter module is automatic range conversion. Digital phase-sensitive demodulator is composed of DAC7524 A/D converter and acquisition module is composed of ICL7135 A/D converter.This paper accomplishes software design. Software section includes acquisition module, CRC check module and communication module. The design concept of each module and program examples are presented. Software development is procedure-oriented, which realize modularized program, have short development cycle and maintain conveniently.Finally, through debugging and testing the instrument, the results certify the design achieved the prospective test function and acquired well test results.