The Study Of Analysis Instrument For Power Quality Based On DSP And CPLD Chips

Nowadays,wider application of modern electronic technology causes serious electronic pollution to power quality,the public power supply quantity is deteriorating, which is a threat to the security and stability of electric power system operation. As a result, how to improve power quality so as to ensure safe and stable operation of electrical equipment has become the focus of attention at home and abroad. Accordance can be provided by real-time monitoring, recording and analysis to power quality. Through analysis of the current domestic and international development of power quality monitor, this paper focuses on a kind of analysis instrument for power quality based on Digital Signal Processor (DSP) and Complex Programmable Logic Device (CPLD) chips, according to current power sector requirements and practical engineering problems.The thesis introduces the basic concept of power quality, and expounds the current research situation of analysis instrument for power quality. Several main methods for power quality analysis are introduced and compared. The author chooses FFT as the basic algorithm because of its applicability and easiness to be realized on DSP, when compared with other main methods.According to the technical indicators that the instrument should achieve, the conceptual design scheme is proposed, constructed by DSP and CPLD as the core, which includes signal acquisition module, A/D conversion module, DSP data processing module, CPLD logic control module, outside enlarge storage module, communication module, keyboard input and LCD module.According to the overall design thought, the author uses power application of DSP development board as the hardware testing system, realizing high-speed data sampling and real-time processing. As peripheral circuit logic control module, CPLD realizes the flexible reliable control of the periphery circuit. A friendly human-machine interface is provided by keyboard input and LCD module.Based on the study of algorithm, C language and assembly language has been used in the software, which not only makes software easy to understand and be easily portabilitied, but also improves the efficiency of the program execution, besides, the detailed program flowchart is presented. Through being tested to the equipment, results manifest that the instrument can work regularly, and the design goal has been realized. Meantime, this paper analyses the possible error and puts forward methods for the software correction.