High-Frequency Harmonic Resonance Suppression in High-Speed Railway Through Single-Phase Traction Converter With <italic>LCL</italic> Filter

Abstract

High-frequency harmonic resonance has been a frequently encountered issue in railway traction power supply system (TPSS) since high-speed trains that are equipped with ac-dc-ac traction drive system were serviced in China High-Speed Railway (HSR) lines. This high-frequency harmonic resonance is excited when the frequency of harmonic components introduced by the grid-side traction ac-dc converter in trains matches the inherent resonance frequency of TPSS. Traditional solutions for this HSR high-frequency resonance focus on providing damping to the TPSS. In this work, with a focus on avoiding the resonance excitation, a solution from the trains' perspective through adoption of single-phase grid-side pulse-width-modulated (PWM) converter with LCL filter in high-speed trains is proposed. Compared with the traditional traction system topology with L-type filter, the total inductance value of LCL filter is designed to be the same with that of L-type filter and there is only an additional small capacitor adopted in the proposed solution. Therefore the design in this work meets the space and weight requirements of the traction converter system. In this work, an all-parallel 27.5-kV 50-Hz autotransformer (AT)-fed power-supply system and the proposed grid-side LCL filter based converters are modeled and simulated in real-time hardware in loop (HIL) experimental platform. The results show that the proposed solution can effectively suppress the high-frequency resonance of TPSS.

A Novel Harmonic Suppression Traction Transformer with Integrated Filtering Inductors for Railway Systems

“…The inductance of the converter side is determined by the modulation method and the permissible maximum current fluctuation. As the unipolar modulation is applied for the traction converter [29] and the current restrictions of the converter side current are set in the range of 30-40% of the rated current [12], the inductance of the converter side inductor can be obtained with…”

“…Figure 7 shows the flowchart of the design and calculation procedure of the proposed HSTT with IFIs. Starting with some selected initial values (P n , V g , f n , U dc , f s , ∆i max , N), the LCL-type filter parameters can be obtained by Equations (11), (12), and (14). Then, it is confirmed whether the resonant frequency of the LCL-type filter meets the limitations given by Equation (16) or not.…”

“…By means of the calculation of the 3D finite element model, the inductance matrix M 12 and corresponding coupling efficiency matrix K 12 covering all windings of the prototype of the transformer integrated with the integrated inductor as below (unit = mH). Here, h1, l1, and i1 represent the high-voltage windings, low-voltage windings, and IFI windings, respectively; the same is true for {h2, l2, i2}, {h3, l3, i3}, and {h4, l4, i4}.…”

“…The BR 101 instrument features a passive harmonics filter instead of an APF (see Figure 1c) [11], in which the filter is damped with resistive devices, thus causing losses. Song et al proposed a single-phase traction converter with an inductive-capacitive-inductive (LCL)-type filter to suppress high-frequency resonance in high-speed railways (see Figure 1d) [12]. This approach can attenuate the high-frequency harmonics in the grid current and damp the LCL-type filter with active damping methods, while maintaining a relatively lower cost.…”

A Harmonic Resonance Suppression Strategy for a High-Speed Railway Traction Power Supply System with a SHE-PWM Four-Quadrant Converter Based on Active-Set Secondary Optimization

“…Sinusoidal pulse width modulation (PWM) technology has been used in electrified railway systems for more than 20 years. This technology produces high-frequency harmonics, which are injected into the traction power supply grid through the pantograph [1][2][3][4][5][6]. The traction power supply system (TPSS) can be equivalent to a distributed parameter system.…”