On fuzzy-PI control for inverted plasma cutting power supply

A fuzzy-PI double-mode controller is proposed in this paper. A variable interval fuzzy quantification algorithm with self-adjustable factor in full domain is also introduced in this paper. The controller combines PI control with this algorithm to study the inverted plasma cutting power supply and its strong nonlinearity and uncertainty in cutting process. This algorithm avoids complex nonlinear system modeling and adopts double-mode control to combine advantages of fuzzy control and PI control under. The optimized fuzzy control improves steady-state precision and dynamic performance of system, either of which the conventional algorithm can realize simultaneously. The simulation result shows that controller proposed in this paper enhances robustness and steady-state performance compared to PI controller or fuzzy controller.