Design and application of nonlinear feedback control system for SPWM inverter fed induction motor drive

During recent years, there has been widespread application of variable voltage variable frequency (VVVF) inverters in industry. Using closed-loop control technology is an extremely important and often difficult problem for the user to deal with using inverter fed motor systems, because the controlled process almost always includes nonlinearity and large inertia, and the linear control systems do not always give satisfactory results. The nonlinear feedback control system with parameter self-adjusting function is developed for the controlled objective which includes strong nonlinearity and very large inertia in this paper. The new system is composed of a large capacity SVF-154 inverter, nonlinear controller and special liquid level sensors. In comparison with a linear feedback control system, this system is very simple, inexpensive, reliable, stable and easier to adjust. The high-performance VVVF inverter is also introduced in detail. The goodness and efficiency of the new control system has been proved already by the practical operating results