Design and implementation of a nonlinear speed control for a PM synchronous motor using the synergetic approach to control theory

This paper presents a novel nonlinear speed control for a permanent magnet synchronous motor (PMSM) using the synergetic approach to control theory (SACT). Recent research has reported that the PMSM is being increasingly used in high-performance applications, such as robots and industrial machines, which require speed controllers that provide not only accuracy and high performance, but also flexibility and efficiency in the design process and implementation. It has also been reported that the best approach to achieve high-performance in a PMSM drive is to consider the whole nonlinear motor dynamics in the controller synthesis. Many control schemes using varied nonlinear strategies have been presented; however, most of them are very complex to design and implement, even when they show good performance. We propose a nonlinear control scheme based on the SACT, which allows the designer to generate the required control laws by following a direct method. This scheme is also well suited for digital control implementation. An interesting outcome of the application of the SACT on the PMSM is the natural linearization and order reduction to a second-order system on the invariant manifold. This result allows the designer to set the desired dynamic behavior of the controlled system by selecting two system poles, as if employing a linear control strategy. The proposed SACT controller is implemented on a PMSM using a DSP-based platform and its performance is verified through the comparison of the experimental and simulation results.