Research Of Three-phase Multi-function Watt-Hour Meter Based On MC68HC908LJ12

Watt-hour meter is an important part of electric power, it is an instrument for measure energy consume quantitative. Watt-hour Meter has high and aboard requests, such as high precision, working stabilization, and altitudinal dependability, it has important meaning for the development of electric power career.In this paper, a new type of three-phase multi-function watt-hour meter which based on high-performance Freescale 8-bit Microcontroller MC68HC908LJ12 be introduced, and the watt-hour meter integrates the functions of measurement, display, control ,protection and communication. ATT7022B is adopted to replace data-collecting hardware circuit. ATT7022B is a multi-functional three-phase electrical energy measurement chip with high precision. This chip can be used in three-phase three-wire and three-phase four-wire appliance, it integrates consult voltage circuit and all electricity parameter measurement digital signals processing circuit include basic wave, harmony wave and so on. This chip has functions of measure all phases active energy ,reactive energy ,apparent energy, voltage rms, current rms, sampled waveform data, frequency and so on. ATT7022B can be used for three-phase multi-functional electrical energy measurement and basic wave, harmony wave Watt-hour Meter. Compared with the traditional method, it not only simplifies the system structure, decreases the cost, but also improves system reliability and accuracy. Moreover, in order to realize the automation of electric system, we adopt RS-485 for remote measuring and control.Firstly,this paper introduce the development of Watt-hour meter and the develop process and basic method of intelligent instrument. Specially,the characteristic of Freescale microprocessor and ATT7022B are introduced. Secondly, according to the technique index and function characteristic, we decide the realization scheme of the whole system and divide whole system into several parts such as check, measurement, control, storage, display, keyboard, communication and power supply. Thirdly, base on the whole system scheme, we describe the soft and hardware process of every part. Finally, we give out the result of debugging and experiment. The test running result shows that the system reaches the expectant affect and purpose.