Design Of The Controller Of The Magnetic-control Soft-startor Based On DSP

According to the scientific statistics, three-phase asynchronous motor's power consumption accounts for more than30%of the national power generation. When starting the three-phase asynchronous motor directly, the starting current could be4-7times of the motor rated current, which would have a larger impact on the power grid and affect the usage life of the motors and the other loads around them. The technology of soft-start can make the motor accelerate smoothly, no mechanical impact, and can reduce the starting current as much as possible to improve the motor starting performance.With the advantages of extensive applicability, high reliability and low cost, the magnetic-control soft-start technology is belong to the ideal soft-start technology at present. Therefore, tha author's project team has carried on deep research to the magnetic-control soft-start technology based on the variable reactor and has developed several magnetic-control soft-start devices. Among, the magnetic-control soft-start device based on PLC needs purchase special device for pulse triggering and voltage/current parameter measuring, causing the controller low integration and great bulk. Meanwhile, owing to PLC's high price, the investment cost is improved. The magnetic-control soft-start device based on dual controller needs controllers to make a cooperation of division of labor, causing the controller bad real-time and liable to be disturbed by external interference. Therefore, a magnetic-control soft-start controller based on DSP is designed in this paper. This soft-start controller is high integration, high reliability and low cost. The main work completed is sumamarized as follows:Firstly, based on the topological structure of the magnetic-controll soft-start device and the type of the microprocessor of its controller being analysed, the design requirements of the magnetic-control soft-start controller based on DSP in the magnetic-controll soft-start device are proposed. And finally, the system structure block diagram of the magnetic-control soft-start controller based on DSP is designed.Secondly, the hardware design of the magnetic-control soft-start controller based on DSP is completed. The function and design solution of each module circuit is analysed in detail as well as the anti-interference measures in hardware are detailed. Thereinto, the hardware circuits mainly include microprocessor's minimum system, acquisition/modulation/convert circuits for three-phase voltage and starting current, synchronous signal detection circuit, drive circuit for thyristors, switching value input/output circuits, communication circiuts between F2812and touch screen, power supply circuit for system and protection circuits and so on.Thirdly, the starting model and control strategy of the magnetic-control soft-start controller based on DSP is analysed and the limited-current fuzzy PID control algorithm and its realizing method are conducted research emphatically.Forthly, using modular structure thought, The software design of the magnetic-control soft-start controller based on DSP is finished. The software flow chart of main module is explained in detail as well as the anti-interference measures in software are detailed. Thereinto, the software flow charts mainly include the whole software structure flow, initialization subprogram flow, self-checking subprogram flow, read soft-starting model subprogram flow, control soft-start process subprogram flow and HMI software flow and so on.