The Design Of The Motor Protector Based On DSPIC Single-chip Microcomputer Control

Because of the use of the motor have permeated all walks of life, including industry,agriculture, aerospace, water conservancy construction, etc., it has been deep into every aspect of people’s life, the number of use is amazing, so it is very important to ensure the normal running of motor. Motor protector is the protection of the motor, it plays a particularly important role to the safe operation of motor. With the rapid development of modern microprocessor technology, based on single-chip microcomputer and digital signal processing technology of motor protector arise, so based on single chip microcomputer and the design of digital signal processing technology of motor protector has become an important topic in today’s world.To realize the reliable protection of the motor, this paper introduces a Microchip DSPIC series microcontroller, the DSP engine can enhance the ability of fast operation and control, to achieve a complete and reliable protection, easy to realize network management,etc. This article is based on DSPIC single-chip microcomputer control unit as the core, to achieve the set acquisition, measurement, judgment, protection, communication and view the function in the integration of the design of the motor protector. Specific content is as follows:This paper studies the protection principle of faults which motor is running, based on over-current protection and the theory of symmetrical component method for three-phase asynchronous motor of residual current, short circuit, overload, underload, three-phase imbalance, overvoltage, undervoltage, locked-rotor and the fault of starting timeout are analyzed in theory, obtaining motor fault current and voltage characteristic at runtime;Theory based on the maximum temperature protection of overheating fault parametric modeling approach is adopted to establish the temperature field of stator end winding model, and applies the ANSYS finite element analysis software, obtaining the temperaturecharacteristic of motor fault runtime. Motor protector was designed using the DSPIC single-chip microcomputer as the core, the hardware system, including signal acquisition and processing circuit, power circuit, clock and interface circuit, man-machine interface and protection circuit. And choose in MPLAB professional compiler environment standard C language to write the software system, including system initialization, data calculation and protection execution, the key input processing. At the same time using the Modbus communication completed the upper and lower position machine communication design,realize the two-way communication between the upper and lower place machine. And in the aspect of hardware and software anti-jamming design of motor protector, based on the concrete anti-interference measures are given. Upon the completion of the design, in order to guarantee the reliability of the motor protector hardware and software, system hardware and software was tested respectively.