改进的双矢量模型预测电流控制用于功率变换器的谐波最小化与开关频率降低

Double-vector model-predictive current control (MPCC) has been widely studied and applied to control pulsewidth modulated (PWM) rectifiers. A recent study showed that the pulse pattern arrangement of two vectors has a significant influence on their current harmonics and switching frequency, and the best pattern includes an appropriate zero vector in the middle of the vector sequence and a nonzero vector equally distributed on both sides of the zero vector; this paradigm is called traditional symmetric double-vector MPCC (TSDV-MPCC). This article proposes two improved asymmetric double-vector MPCC (IADV-MPCC) methods. In IADV-MPCC I, the duration of the nonzero vector is optimized to achieve minimal current harmonics; this strategy no longer maintains symmetric distribution features on both sides of the zero vector. In IADV-MPCC II, not only the duration of the nonzero vector is optimized; the vector sequence is also optimized by relaxing the vector combination to two nonzero vectors at high modulation indices. Furthermore, the vector sequence is dynamically adjusted to achieve a reduced switching frequency. The proposed IADV-MPCC is compared to a series of MPCC methods, including TSDV-MPCC, MPCC using two nonzero vectors (MPC2) and deadbeat control based on space vector modulation (DB-SVM). The experimental results confirm that, compared to TSDV-MPCC, the current total harmonic distortion (THD) and switching frequency are reduced by more than 48% and 20%, respectively, at high modulation indices. Compared to MPC2, the current THD is reduced by 22.58%, while maintaining a similar switching frequency. Compared to DB-SVM, the current THD and switching frequency are reduced by more than 17% and 15%, respectively, at high modulation indices. Finally, the proposed IADV-MPCC exhibits similar dynamic response to the other methods.