Improved MPCC with Duty Cycle Modulation Strategy for Linear Induction Machines based on Linear Metro

The traditional finite control set-model predictive thrust control (FCS-MPTC) method for linear induction machines (LIMs) needs to find appropriate weighting factor (WF) for adjusting the cost function, which make the control methodology much long and tedious by the huge tuning procedures of possible try cases to obtain the best WF. So two methods are suggested in this work to overcome the tuning prosses and reduce the complexity burden of the control system. The first method is finite control set-model predictive current control (FCS-MPCC I), to get the optimal voltage vector (OVV) depending on the distance between the determined reference voltage vector (RVV) and all of the participant voltage vectors (PVVs) without repetitive enumeration, by determining the sector owns the RVV. The other method is FCS-MPCC II, by applying two voltage vectors during one switching period with adjusting the duty cycle between them, similar to the previous method to found out the OVV. Avoiding redundant comparative all PVVs, only one of the two adjacent active voltage vectors can be selected depending on the sector owns the RVV. Finally, comprehensive simulation and analysis have been made through a whole comparative study between the traditional FCS-MPTC and the two suggested FCS-MPCC methods. Persuasive effectiveness of the proposed FS-MPCC has been verified whereas reduced calculation time and complexity are elaborated based on the proposed search order. Meanwhile, much lower thrust ripples can be further got compared to those of the conventional FCS-MPTC.