A 45-m-long high-temperature superconducting (HTS) Maglev ring test line, named as "Super-Maglev", has been successfully developed in Chengdu, China in February, 2013, 12 years after the birth of the first man-loading HTS maglev test vehicle. The maglev vehicle (2.2 m in length, 1.1 m in width) is designed for one passenger with a levitation height of 10-20 mm; the permanent magnet guideway (PMG) (45 m in length, 0.77 m of track gauge) is a racetrack shape with a curve radius of 6 m; the driving is accomplished by a linear induction motor with a maximum running speed of 50 km/h. The linear motor is composed of four sub-motors installed at one straight section in the middle of the double PMGs and the total length is 3 m. Thissecond-generation HTS Maglev vehicle system is highlighted by the cost-performance and the wireless multi-parameter onboard monitoring function. The current same-level load capability has been achieved over a small-section low-cost PMG whose cross sectional area is only 3000 mm 2 . On the vehicle, parameters of levitation weight, levitation height, running speed, acceleration, lateral offset, online position and total running distance of the vehicle are real-time monitored and displayed on the onboard tablet computer. The system component and test data are reported in detail in the paper.

No abstract

Summary The estimation of state‐of‐charge (SOC) is crucial to determine the remaining capacity of the Lithium‐Ion battery, and thus plays an important role in many electric vehicle control and energy storage management problems. The accuracy of the estimated SOC depends mostly on the accuracy of the battery model, which is mainly affected by factors like temperature, State of Health (SOH), and chemical reactions. Also many characteristic parameters of the battery cell, such as the output voltage, the internal resistance and so on, have close relations with SOC. Battery models are often identified by a large amount of experiments under different SOCs and temperatures. To resolve this difficulty and also improve modeling accuracy, a multiple input parameter fitting model of the Lithium‐Ion battery and the factors that would affect the accuracy of the battery model are derived from the Nernst equation in this paper. Statistics theory is applied to obtain a more accurate battery model while using less measurement data. The relevant parameters can be calculated by data fitting through measurement on factors like continuously changing temperatures. From the obtained battery model, Extended Kalman Filter algorithm is applied to estimate the SOC. Finally, simulation and experimental results are given to illustrate the advantage of the proposed SOC estimation method. It is found that the proposed SOC estimation method always satisfies the precision requirement in the relevant Standards under different environmental temperatures. Particularly, the SOC estimation accuracy can be improved by 14% under low temperatures below 0 °C compared with existing methods. Copyright © 2017 John Wiley & Sons, Ltd.

A novel optimisation method of LCL filter based on closed-loop total harmonic distortion (THD) calculation model of the grid-connected inverter is proposed in this study. If the parameters of the LCL filter are large enough, the current harmonics can be significantly inhibited. However, the size, weight and price of the filter may increase. If the parameters of the LCL filter are too small, the attenuation of the current harmonics may be not enough. In the proposed method, the target of optimisation is to obtain the minimum value of the inductors on the premise of the allowed current harmonics. The harmonics should be analysed and the control-loop should be taken into consideration. According to this, a closed-loop THD calculation model is established. Generalised reduced gradient (GRG) method is applied to do the optimisation based on the model. With the optimised parameters of LCL filter, the size, weight and price of the filter can be reduced. The relationship between THD and the parameters of the LCL filter is analysed. The principle of GRG is discussed. Finally an 18 kVA three-phase grid-connected inverter with the optimised LCL filter has been established and tested. Simulation and experimental results verify the theoretical analysis.

No abstract