| The Three-Phase Asynchronous Motor is widely used in production and life because of its simple structure, small size, convenient maintenance and low price. Its market share consistently surpasses other types of motors. People require higher starting performance demand on the three-phase asynchronous motor in extensive use. Traditional voltage-reduced start mode has a great deal of abuse; it cannot eliminate the current surge. Soft starter advent in the 80s, make asynchronous motor start in a smooth level. Steady rise of starting current avoid harmonic pollution to the power, ensures the stability of the grid voltage, and improves the life of power supply equipment.This article is based on theory of SCR to control voltage phase using fuzzy control in starting process based on voltage control, controlling structure analysis of fuzzy control system and control theory, based on soft-starting control system on the basis of need, identifying fuzzy rules and fuzzy-fuzzy reasoning and anti-blur, Finally the design of fuzzy controller of soft starter is completed.In this article, AT89S52 Single-chip computer is the core, hardware circuit of soft starter is designed, including main circuit, AT89S52 Minimum system, detection circuit of power factor angle, A/D Conversion circuits, the voltage and current detection circuit, SCR trigger circuit, display and keyboard circuits. Software design of soft start control system programming is divided into the main program and the program design of important parts in design process, voltage is processed using fuzzy control algorithm. Then software design of voltage fuzzy control is completed.Working principle and parameter of three-phase AC induction motor are analyzed, mathematical models are established and simulated, and simulation shows the soft starter design program of the feasibility. And through the test, the correctness of the relevant control strategy for soft start controller is verified. |
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