Abstract
This dissertation is mainly concerned with the development of a DSP-based linear permanent magnet synchronous motor (LPMSM) drive and its digital positioning control. First, a LPMSM driven stage is established, and a DSP-based digital control environment is constructed for realizing all the developed control algorithms. In addition to the properly designed current-controlled PWM scheme in the established drive, a field-weakening forcing current control scheme is proposed to improve current tracking response during transient period. As to the positioning control studies, the dynamic model of the motor drive is first estimated from measurements. And it is employed for performing the controller design at nominal case. Moreover, the quantitative design approaches are developed to find the parameters of two-degree-of-freedom controller (2DOFC) based on the estimated model and the prescribed control requirements. As the system parameter and operating condition changes occur, the given control requirements will not be further satisfied. In this dissertation, an observer based robust control scheme and an internal robust model following controller are proposed to reduce the performance degradation. In addition, the parameter identifiers are devised to obtain the dynamic model parameter changes from the observed disturbance or the compensating control signals. The estimated parameters are then used for on-line adapting the parameters of the 2DOFC. In making large command positioning control, the amplitudes and/or ramping rate of step and ramp commands are determined according to the estimated parameters. The ratings of inverter and motor can be utilized more effectively. Excessive control saturation and instability caused by nonlinearities can be avoided. And moreover, the positioning response time is also predicable.