Dian, R, Xu, W, Zhu, J, Hu, D & Liu, Y 2018, 'An improved speed sensorless control strategy for linear induction machines based on extended state observer for linear metro drives', IEEE Transactions on Vehicular Technology, vol. 67, no. 10, pp. 9198-9210.View/Download from: UTS OPUS or Publisher's site
© 2018 IEEE. This paper proposes an improved systematic approach for sensorless speed estimation and controller design of a linear induction machine (LIM) for linear metro drives. A novel speed estimation method based on the extended state observer is developed to improve the dynamic speed estimation response. In contrast to the conventional proportional-integral speed adaptive mechanism based only on the LIM electromagnetic model, this new speed estimation method incorporates both the electromagnetic and mechanical models such that it can estimate the LIM speed and load resistance at the same time. A new speed controller incorporating the disturbance observer based control algorithm is developed to strengthen the speed tracking ability and suppress the disturbance of load variation. Having fewer parameters, it brings great convenience to the drive system parameter setting and tuning. The performance of the proposed method is numerically simulated and experimentally verified.
Hu, D, Xu, W, Dian, R, Liu, Y & Zhu, J 2018, 'Loss Minimization Control of Linear Induction Motor Drive for Linear Metros', IEEE Transactions on Industrial Electronics, vol. 65, no. 9, pp. 6870-6880.View/Download from: UTS OPUS or Publisher's site
© 1982-2012 IEEE. The linear induction motor (LIM) drive in linear metros suffers heavily from low efficiency due to its large air-gap length and the partial load conditions, where high loss appears in both the LIM and the inverter when a constant excitation current is generally required. Worse still, the end-effects, including both the transversal edge-effect and longitudinal end-effect, would lead to the decrease of magnetizing inductance and the increase of secondary resistance, resulting in extra loss and further deterioration of drive efficiency. To reduce the loss of the LIM drive, this paper proposes a novel loss model based loss minimization control (LMC) scheme for LIM drives. First, in the equivalent circuit and the mathematical model of LIM, four coefficients are introduced to evaluate the influence of the end-effects. Based on a thorough analysis of the LIM copper and core losses, together with the inverter conduction and switching losses, a novel integrated loss model of LIM drive is then developed, and an improved LMC scheme to obtain the optimal solution online is proposed to minimize the loss of the LIM drive. The proposed control method is successfully implemented in a 3-kW LIM drive prototype. The effectiveness of the proposed method is validated by the experimental results.
Abdolali, A, Ngo, HH, Guo, W, Zhou, JL, Zhang, J, Liang, S, Chang, SW, Nguyen, DD & Liu, Y 2017, 'Application of a breakthrough biosorbent for removing heavy metals from synthetic and real wastewaters in a lab-scale continuous fixed-bed column.', Bioresource Technology, vol. 229, pp. 78-87.View/Download from: UTS OPUS or Publisher's site
A continuous fixed-bed study was carried out utilising a breakthrough biosorbent, specifically multi-metal binding biosorbent (MMBB) for removing cadmium, copper, lead and zinc. The effect of operating conditions, i.e. influent flow rate, metal concentration and bed depth was investigated at pH 5.5±0.1 for a synthetic wastewater sample. Results confirmed that the total amount of metal adsorption declined with increasing influent flow rate and also rose when each metal concentration also increased. The maximum biosorption capacities of 38.25, 63.37, 108.12 and 35.23mg/g for Cd, Cu, Pb and Zn, respectively, were achieved at 31cm bed height, 10mL/min flow rate and 20mg/L initial concentration. The Thomas model better described the whole dynamic behaviour of the column rather than the Dose Response and Yoon-Nelson models. Finally, desorption studies indicated that metal-loaded biosorbent could be used after three consecutive sorption, desorption and regeneration cycles by applying a semi-simulated real wastewater.