In order to further improve the energy-saving and voltage stabilizing effect of the stationary energy storage system (ESS), this article tries to adopt the battery-supercapacitor (SC) hybrid ESS (HESS) as stationary ESS. The advantages of stationary HESS are verified by an example. An adaptive energy management framework for stationary HESS is proposed. A power distribution strategy is proposed to solve the adaptability of two energy storage media to the load variation of rail transportation power system, and to a certain extent, the battery degradation is delayed. The proposed strategy can not only realize the reasonable power-sharing between battery and SC considering the influence of headway on regenerative braking energy but also can keep the battery’s charge and discharge capacity for a long time by using fuzzy logic control (FLC). A simulation is carried out to illustrate the advantages of the proposed energy management strategy (PEMS). Finally, the PEMS is compared with two conventional strategies by the hardware-in-the-loop experiment platform, where it is shown to provide better performance (inferred through increases of 1.1% and 5.7% in energy conservation rate, 0.82% and 6.4% in voltage stabilization rate, and reduction of 2.26 and 0.36 A in the root-mean-square value of battery current at different headway).

In order to absorb the regenerative braking energy of trains, supercapacitor energy storage systems (ESS) are widely used in subways. Although stationary ESS are widely used, because of the influence of no-load voltage, and so on, a stationary ESS cannot absorb all the regenerative braking energy in some special cases, and the brake resistor is still activated, which leading to the wasting of energy. In order to completely replace the on-board brake resistor, this paper configures a certain on-board supercapacitor, and based on a DC-side series supercapacitor topology, proposes a hierarchical optimization energy management strategy (EMS). The EMS is divided into three layers: Firstly, the strategy can increase the inverter-side voltage in a short time without changing the traction network voltage, and improve the train braking characteristic curve by utilizing the short-time overvoltage capability of the inverter and the motor; Secondly, by coordinated control with a stationary supercapacitor, the residual regenerative braking energy can be absorbed even in special cases; Finally, based on loss calculation and current prediction, this strategy can effectively reduce the system loss by adjusting the DC voltage on the inverter-side. The proposed control strategy is validated through simulation and RT-LAB experiment, and the experimental results agree well with the theory.

This article proposes a finite set modelpredictive current control scheme for traction permanent magnet synchronous motors for railway application. For the rail transit drive system, it is necessary to realize the six-step operation. A method based on voltage vector clamping is presented to realize overmodulation including six-step operation and maximize the utilization ratio of dc voltage. The essence of voltage vector clamping is to gradually reduce the space of action of the closed-loop regulation mechanism until it enters six-step operation. This method is simple and feasible, which does not need to add controllers or switch the control framework. An ideal voltage vector reference coordinate system is established to analyze the current trajectory under different modulation ratios. Thus, an optimal control strategy in the ideal voltage reference coordinate system is proposed. Experiments are conducted to prove that six-step operation can be achieved and this strategy has an obvious effect on switching frequency index in the overmodulation area.

In this paper, an adhesion control strategy based on the wheel-rail adhesion state observation is proposed for high-speed trains. First, the high-speed train single axle dynamics model is established. Then, a modified adhesion control method is proposed. The scheme observes the tangential force coefficient between wheel and rail through full dimension observer and forecasts the slope of the adhesion-slip curve by the recursive least squares method with forgetting factor. Meanwhile, a feasibility analysis of the method and the control parameters tuning is conducted. Afterwards, the experimental study of the proposed adhesion control is carried out based on a 5.5 kW induction motor drag platform using dSPACE simulation technology. The experimental results confirm the feasibility of the adhesion control method proposed in this paper. Using the proposed adhesion control method can achieve high wheel-rail adhesion performance under variable complex road conditions.

For multiobjective model predictive current control (MPCC) method with penalties, the penalty weights are introduced into the cost function to determine the relative importance of control targets. However, the dimensions and value ranges of each control target are different. Thus, the penalty coefficient is difficult to determine. To avoid the difficulty of dimensionless parameter design, this article proposes a multiobjective control method called MPCC with multiple current bounds. In this article, the switching frequency and the common-mode voltage (CMV) are selected as the control target. Their control is converted into the limitation of the current ripple so that the control parameters have a clear physical meaning. On the one hand, the proposed method can realize the cooperative control of reference current tracking, switching frequency suppression, and CMV suppression. On the other hand, the key control parameters have the same dimension and strong correlation with others. Therefore, appropriate parameter design can be realized. Experimental investigations for permanent magnet synchronous motor prove the effectiveness of the control method.