Harmonic Mitigation in Electric Railway Systems Using Improved Model Predictive Control

Abstract

An electric multiple unit (EMU) high-speed train is the dynamic load that degrades the power quality in an electric railway system. Therefore, a power quality improvement system using an active power filter (APF) must be considered. Due to the oscillating load current in the dynamic load condition, a fast and accurate harmonic current-tracking performance is required. As such, this paper proposes the design of a model predictive control (MPC) since the minimization of cost function in the MPC process can suitably determine APF switching states. The design technique of MPC is based on the APF mathematical model. This controller was designed to compensate the time delay in the digital control. Moreover, the synchronous detection (SD) method applied the reference current calculations, as shown in this paper. To verify the proposed MPC, the overall control of APF was implemented on a eZdsp F28335 board by using the hardware-in-the-loop technique. The testing results indicated that the proposed MPC can provide a fast and accurate harmonic current-tracking response compared with the proportional-integral controller. In the load changing condition, the MPC was still effective in providing a good result after compensation. The percentage of total harmonic distortion, the percentage current unbalance factor, and the power factor would also be kept within the IEEE Standard 519 and IEEE Standard 1459.

A positive, negative and zero sequences electric power, to improve upon the standard IEEE 1459-2010

“…The results show that the determination of the total equivalent power and power factor can take into account the unbalanced loads effect on the transmission line efficiency. Researchers of traction systems with a dynamic load come to similar conclusions, offering a solution to improve of electrical energy quality using an active power filter (Panpean et al, 2021). Qualitative and quantitative assessments are made by the authors using the recommendations of the previously mentioned standard.…”

Detection of Harmonic Overvoltage and Resonance in AC Railways Using Measured Pantograph Electrical Quantities

“…In particular, as mainly focused on by the EN 50388 standards [2,3] regarding the interaction between rolling stock and the supply traction line, harmonic distortion and, in general, conducted emissions may cause local disturbances to signaling and control devices as well as supply line distortion, instability, and overvoltages. The first have been subject to extensive research for PQ indexes and criteria [1], as well as compensation strategies and implementations [4][5][6][7][8]. The latter are the objectives of recent research aimed at defining the conditions for line instability, harmonic resonances, consequences in terms of excessive distortion, and insulation breakdown [9][10][11][12][13].…”

Detection of Harmonic Overvoltage and Resonance in AC Railways using Measured Pantograph Electrical Quantities

“…In particular, as mainly focused by the EN 50388 standards [2,3] regarding interaction between rolling stock and supply traction line, harmonic distortion and in general conducted emissions may cause disturbance locally to signaling and control devices, as well as supply line distortion, instability and overvoltages. The first have been subject to extensive research for PQ indexes and criteria [1], as well as compensation strategies and implementations [4][5][6][7][8]. The last are the objectives of recent research aiming at defining the conditions for line instability, harmonic resonances, consequences in terms of excessive distortion and insulation breakdown [9][10][11][12].…”