Operation Control Of Permanent Magnet Synchronous Motor Drives Using Matrix Converters

Matrix converters are single stage power converters. They have received a good deal of attention in the fields of power electronics and electric drives due to their advantages like reduced harmonics, adjustable input power factor, bidirectional energy transmission, high power density and so on. In this paper, the PMSM drive system fed with matrix converters is studied concerning on its operation and control. The major work presented in this paper includes analysis of matrix converters'operating characteristic in a MC-PMSM system, stability analysis of the system and improvement for the sysem on dynamic and steady performance under input voltage disturbance.Based on the High Frequency Synthesis principle, the relationship between the input and the output of MC is analyzed, and the control law of Space Vector PWM is derived. With the basic modulation strategy, a MC system with inductive load is modeled and analyzed on its stability. Different methods for developing system stability are discussed and compared. Finally, a conclusion that stability of system is dependent on power circuit topology and modulation strategy of MC has been drawn, and it is used as a guide for parameters selection in experimental setup design.On the problem of comparatively low voltage transfer ratio of MC, current vector loci and voltage vector ellipse set are plotted to evaluate operating performance of MC-PMSM system controlled by vector control strategy. Stability problem causes output power of MC system to be limited under its nominal value. In this paper, state equations of the MC-PMSM system are derived. These equations are linearized around its steady operating point, and the relationship between stability and parameters of the system is obtained according to stability criterion. The results are used as a reference for design of input power filter to make the speed regulating system meet desired output power.Disturbance from inputs of MC has significant effects on its output due to the direct connection topology. In addition, the nonlinear output characteristic of MC also increases the complexity of precise control for MC-PMSM system. A strategy based on internal model control (IMC) is proposed to reduce the adverse impact on drive performance caused by nonlinear output characteristic of matrix converter in the case of input voltage disturbance. The nonlinear output characteristic of MC is modeled in space vector form. Internal and external causes which affect output performance are analyzed and discussed after a linear process for the model. Design specifications are updated according to the analysis results. Then, structures and parameters of both speed and current controllers are redesigned. Simulation and experiment show that good dynamic and steady performance on PMSM speeding is achieved under the unbalanced input voltage condition, and the immunity to disturbance of the drive system is verified to be improved.An MC-PMSM experimental setup is built by using a digitized controller structure with Micro Control Unit (MCU) and FPGA. The analysis of nonlinear output characteristics of MC and the evaluation of system performance under input voltage disturbance are tested on the experimental setup. Finally, conclusions in the paper are supported, and the proposed strategy is verified by the experimental results.