Flexible Constraint Model Predictive Current Control of SMPMSM Drives with Switching Frequency Reduction

To achieve double‐objective optimization of the current performance and inverter switching frequency for surface mounted permanent magnet synchronous motor drives, a flexible constraint model predictive current control is proposed based on a hybrid voltage vector. The cost function includes current performance, which is transformed into a form that relates only to the phase of the voltage vector while satisfying optimal amplitude. Then, the candidate voltage space is derived based on the preset flexible constraint of the cost function. Moreover, the principles for selecting the optimal voltage vector from the space are presented to reduce the switching frequency of the inverter. With this method, controllable and consistent current performance under various operating conditions can be achieved, while the switching frequency of the inverter is effectively reduced. In addition, the proposed method avoids the use of the weighting factor. The comparative experimental tests are implemented to demonstrate the effectiveness of the proposed method.