Fuzzy logic-based control of flux and torque in AC-drives

A control method based on fuzzy logic is proposed for the regulation of torque and flux in AC drives fed by pulse-width-modulated (PWM) inverters. The input signals of the controller are transformed by fuzzy sets in six categories valued by membership functions. The interaction between the input signals and the outputs is realized by fuzzy logic consisting of special production rules corresponding with the well-known principle of direct self-control. Two strategies are derived to obtain the optimal voltage phasor and the pulse-time of the inverter switches. The experimental results show the advantages of the new control regime by keeping constant the pulse frequency using a nonlinear controller in connection with a pulsewidth modulator. >