Search

The direct torque control (DTC) technique of a permanent magnet synchronous motor (PMSM) has received increasing attention due to its simplicity and robust dynamic response compared with other control techniques. The classical switching table based DTC presents large flux, torque ripples and more mechanical vibrations in the motor. Several studies have been reported in the literature on classical DTC. However, the studies that actually discuss or evaluate the classical DTC are limited. This paper proposes, an alternative DTC method/switching table for PMSM, to reduce flux and torque ripples as well as mechanical vibrations. This is achieved by a simple modification in the classical DTC structure, by eliminating the two level inverter available in the classical DTC and replacing it with a three level neutral point clamped inverter. To further improve the performance of the proposed DTC, the available 27 voltage vectors are allowed to form different groups of voltage vectors such as Large - Zero, Medium - Zero and Small - Zero. Based on these groups, a new switching table is proposed. The proposed DTC is compared with the classical DTC and existing literature from the aspects of theory analysis and computer simulations. It can be observed that the proposed technique can significantly reduce the flux, torque ripples, and mechanical vibrations and improves the quality of current waveform compared with traditional and existing methods. [ABSTRACT FROM PUBLISHER]

This paper presents an improved fuzzy logic controller (FLC) for a permanent magnet synchronous motor (PMSM) for high performance industrial drive applications. The performance of the PMSM using proportional plus integral (PI) controllers and general fuzzy controllers are poor under load disturbances and transient conditions. The FLC is developed to have a smaller computational burden which makes it suitable for real time implementation, particularly at constant speed operating conditions. Hybrid control has the advantage of integrating a superiority of two or more control techniques for better control performances. A fuzzy controller offers better speed responses for startup and large speed errors. If the nature of the load torque is varied, the steady state speed error of the PMSM drive with an FLC becomes significant. To enhance the performance of the system, a new control method, hybrid fuzzy PI control and accelerated fuzzy PI control is proposed. The effectiveness of the proposed method is verified by a simulation based on MATLAB. The proposed hybrid fuzzy controller has good adaptability over load toque variation and can maintain constant speed. [ABSTRACT FROM PUBLISHER]

In this paper, an adaptive controller is developed to suppress chaos and track the desired speed in an uncertain chaotic permanent magnet synchronous motor (PMSM) drive system. The controller consists of computational and supervisory control schemes. The computational controller, based on fuzzy neural networks, is used to approximate the unknown nonlinear control signal, while the supervisory controller is employed to attenuate the approximation error effects of the neural network and ensure the system is robust. Simulation results demonstrate that the proposed controller can successfully quash chaotic oscillation in a PMSM and allow speeds to follow the desired trajectory despite the existence of uncertainties. [ABSTRACT FROM PUBLISHER]