Study On The Intelligent Variable Frequency Adjustable Speed System Based On DSP

With the development of power electronic technology, electric drive technology faces a historical revolution, AC converter is gradually replacing DC converter, which has become a trend. AC motor converter has become a main measure to save energy, upgrade product quality, improve the environment and promote technological advancement with its excellent starting and braking ability, high efficiency and energy-saving effect. "Study on the Intelligent Variable Frequency Adjustable Speed System based on DSP" is chosen in order to bring advantages of digital signal processing technology combined with intelligent control theory into play, and to improve digital level and intelligent level of the variable frequency adjustable speed system based on the informed research.With VVVF principle, vector control principle, SVPWM theory and technology, variable-speed system is designed to be modules in the paper, which reduces component count and the size of the system, and improves static and dynamic performance and reliability. In actual control process, non-linear factors and parameter time-varying cause control accuracy of the system unable to meet the need and poor stability, to solve the inherent problem, the traditional PID control is unable to do anything, but the intelligent control can effectively improve the system robustness. Fuzzy PID controller is adopted to control speed loop in the paper, which takes place of common PID controller, as a result, smaller overshoot and static error are gotten, system performance is improved accordingly.As for system hardware, it is made up of circuit cored around DSP and IPM, including the main circuit, control circuit and protection circuit. The main circuit consists of the rectifier, filter, inverter circuit; the control circuit consists of the external program memorizer expansion circuit, decoding circuit, setting and displaying circuit, and voltage,current, speed, position detection circuit; the protection circuit consists of off-phase, over-heat, over-flow, over-voltage protection circuit.As for system hardware software, relative program modules for the entire system are designed on the core of vector control algorithm. The system software is composed by the main program and interrupt service subroutine. The main program mainly finishes initialization work; subroutine includes the following modules: SVPWM program design, PID control program design, rotor flux linkage orientation program design, CLARKE transform and its inverse transform program design, PARK transform and its inverse transform program design, setting and displaying program design.Simulations on the variable-speed system are finished at the end of this paper. The variable frequency adjustable speed system based on the traditional PID speed controller and the variable frequency adjustable speed system based on the fuzzy PID speed controller are simulated and analyzed respectively. Compared the two simulation results:the latter has better dynamic and static speed performance, so the rationality of the system is proved.