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Weihan Tang,Zhangyong Chen,Yong Chen,Yunyan Liu,Tieqi Wang,Zhiyuan Chen 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.6
The multi-level inverter (MLI) is more efficient due to its ability to eliminate low-order harmonics. Thus, it is widely used in renewable energy generation, electric vehicles (EVs), etc. The choice of the neutral-point clamped (NPC) converter topology as a research object is of great significance in practical engineering. However, complex modulation algorithms and neutralpoint voltage unbalance are two inherent problems for such NPC inverters. In this paper, an improved multi-voltage vector model predictive control (MVV-MPC) strategy based on neighboring four voltage vector synthesis is presented for threephase NPC inverters. The duty cycle calculation and derivation methods for the proposed method are very simple, and they were obtained through the action time of each voltage vector being inversely proportional to the value of the corresponding cost function. Moreover, the fixed switching frequency of this strategy is maintained and the current peak ripple is reduced, guaranteeing the preferred total harmonic distortion of the output waveform. Furthermore, a voltage balancing method based on zero-sequence voltage injection is utilized to achieve dynamic balancing of the midpoint voltage difference and to limit the oscillation magnitude of the midpoint voltage difference to within ± 1 V. Finally, MATLAB simulations and an HIL experimental platform are built to demonstrate the effectiveness of the proposed method.
Chen Zhangyong,Xiao Fangbo,Chen Yong,Tang Weihan,Chen Zhiyuan 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.6
In permanent magnet synchronous motor (PMSM) application, model predictive direct speed control is usually utilized to eliminate cascade loop structure existed in traditional vector control. However, asynchronous prediction equation (ASPE) with one-step delay is mostly required to achieve optimal voltage vector to drive the PMSM motors, which exist the problem of asynchronous prediction of speed and current. It is shown that in this paper the synchronous prediction equation (SPE) does not have the prediction delay, but it cannot realize the speed tracking control. Aim to solve the above problems, an improved PMSM model predictive direct speed control with synchronous prediction and Weight factor optimization is proposed in this paper. Firstly, the Taylor synchronization prediction equation (TSPE) is used to realize the speed and current prediction synchronization and the speed tracking control. Secondly, in order to improve the response speed of the system, a quadratic cost function considering the weight factor optimization is used for cost evaluation, and the Lyapunov direct method is used to design the weight factor with taking into account the stability and rapidity of the system. Finally, in order to verify the effectiveness of the proposed method, the MATLAB simulation and hardware-in-the-loop experiments are carried out. The results show that the proposed control method achieves predictive synchronous between speed and current, fast and stable speed tracking control, and the setting time is faster than the ASPE, and the TSPE without considering the weight factor.