基于PIC16F876单片机的智能低压电动机综合保护器的研究

为解决市场上现有各种电动机保护器功能与成本之间的矛盾,研制了一款高性价比的以Microchip公司的PIC16F876单片机为核心的智能低压电动机综合保护器。重点介绍了热过载保护的反时限特性和启动保护与运行保护的区别。提出了一种特定算法用于程序中的计算,有效地解决了定点运算精度低和浮点运算计算量大、计算时间长的问题。在装置的结构和软硬件设计中,采用了多种抗干扰措施,以提高装置的可靠性与抗干扰能力。动态模拟试验和现场运行结果表明,此保护器能对低压电动机的各种故障做出准确判断且具有良好的可靠性、重复性,其动作值、动作时间的精度能达到一般工业现场要求。

Study of an intelligent low-voltage integrative motor protector based on PIC16F876 single chip

To resolve the contradiction between the function and the cost of the motor protectors in the market, a high performance-cost ratio and intelligent low-voltage integrative motor protector based on PIC16F876 single chip of microchip incorporation is designed. The inverse time characteristic of overload protection and the differences of starting protection and running protection are described in detail. A special algorithm is put forward to calculate in program, it solves the problem about low precision of fixed-point operation and high computation cost and long computation time of floating-point operation. To improve the reliability and the anti-interference ability of the equipment, many anti-interference measures are taken in designing the hardware and software. The results of dynamic simulation and test in the field indicate that this motor protector could make precise judgement to every kind of faults of the low-voltage motor protector and have higher reliability and repetition. The precisions of its action value and action time can meet the need of general egineering application. This project is supported by Heilongjiang Technologies R&D Programme(No.GB02A103).