<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
    <description></description>
    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
    </image>
    <item>
      <title>Modeling and Analysis of a Hybrid Co-Phase Traction Power Supply System Considering Minimum Compensation Capacity and Flexible Standby Strategy</title>
      <link>https://trid.trb.org/View/2735066</link>
      <description><![CDATA[The co-phase traction power supply system (TPSS) is an ideal solution for safe and efficient rail transit. To ensure reliability, the current topology adopts a 100% redundancy design, which results in high investment costs. To improve converter utilization and reduce costs, this article proposes a hybrid co-phase TPSS (HCTPSS) and a coordinated control strategy between the primary power supply equipment (PPSE) and standby power supply equipment (SPSE) under N -1 equipment faults (single-converter failure). A comprehensive compensation model is derived to determine the minimum compensation capacity required for power quality improvement under both healthy and fault conditions, and a control strategy is developed to ensure reliable operation. Compared with existing combined co-phase TPSS (CCTPSS), the HCTPSS can utilize existing Vv transformers, and compared with existing hybrid power quality conditioner (HPQC) schemes, it requires smaller converter installation capacity. Case studies and experimental results show that, for a practical traction substation retrofit, the proposed scheme can reduce total investment costs by 5288 and 4581 kCNY compared with the two existing schemes while maintaining power supply reliability, demonstrating the effectiveness and economic advantages of the HCTPSS.]]></description>
      <pubDate>Fri, 14 Aug 2026 15:05:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2735066</guid>
    </item>
    <item>
      <title>RPC Coordinated Control Strategy with Battery and Flywheel Energy Storage</title>
      <link>https://trid.trb.org/View/2579254</link>
      <description><![CDATA[Having the features of safety, reliability, comfort, significant transport capacity, and relatively low time consumption, the electrified railroads are an effective way to solve traffic congestion. However, with the speedy progress of China’s electrified railway, power quality problems such as harmonics and negative sequences have received widespread attention, while more and more problems of regenerative braking energy not being effectively used in the traction power provision system have also emerged. Nowadays, traction substations are charged according to the two-part tariff, and the problem of ineffective use of regenerative braking energy will result in higher charges for the two-part tariff, which has a greater economic impact. The installation of railway power conditioner makes the issue of power quality effectively addressed, thus how to solve the power quality using the remaining regenerative braking energy, reducing the peak load to improve the economy has become the focus of national and international research. Due to the flexible charging and discharging characteristics of the energy storage device, it can make full use of the recycled braking electricity and reduce the peak load simultaneously. In light of the aforementioned background, this paper explores the control strategy and parameter adjustment of the power regulator for railway and energy storage system by using the data collected in an actual substation. The coordinated control strategy of battery and flywheel energy storage device is proposed for the real-time data of railroad locomotive traction load. By means of the new system of railway power regulator and energy storage device, the simulation model of actual working conditions is utilized to validate the strategy. The results indicate that the control strategy can perform well in power quality management and regenerative braking energy recovery. Meanwhile, when the peak load arrives, it can maximally and effectively reduce the peak load, thus not only managing the power quality but also further enhancing the economic returns.]]></description>
      <pubDate>Fri, 31 Jul 2026 16:05:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2579254</guid>
    </item>
    <item>
      <title>A Real-Time Hierarchical Energy Management Strategy for FTPSS to Improve the PV/RBE Utilization and Power Supply Quality</title>
      <link>https://trid.trb.org/View/2512352</link>
      <description><![CDATA[The flexible traction power supply system (FTPSS) based on the railway power conditioner (RPC), photovoltaic (PV), and energy storage system (ESS) can realize energy exchange between substations while providing an opportunity for efficient use of PV and regenerative braking energy (RBE). However, the power of PV and traction loads (TL) has multi-directional, large amplitude, and high-frequency fluctuation characteristics in the FTPSS. Thus, realizing efficient and high-quality dispatch for FTPSS has become a pressing challenge under the real-time energy management requirements. To this end, a real-time hierarchical energy management strategy (EMS) for FTPSS to improve the PV/RBE utilization and power supply quality is designed. First, a cooperative mechanism for energy hierarchical management is developed. That is, the multi-station level carries out cluster management in 10s, and the substation level carries out autonomy management in 1s. Secondly, a unified active-reactive power flow model for FTPSS is established at the multi-station cluster management level, determining the optimal power flow for the FTPSS and the line power losses. Meanwhile, a combined rule-based and optimization EMS is proposed at the substation autonomy management level, which combines the advantages of high timeliness of rule-based EMS with the multi-objective synchronization gain of optimization EMS. Finally, the performance of the proposed strategy is verified on the MATLAB simulation platform and RT-LAB semi-physical platform based on measured data.]]></description>
      <pubDate>Wed, 05 Nov 2025 10:04:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2512352</guid>
    </item>
    <item>
      <title>Ill-Conditioned Power Flow Calculation in Urban Rail Traction Power Supply System</title>
      <link>https://trid.trb.org/View/2559287</link>
      <description><![CDATA[In the traction power supply system (TPSS) of urban rail transit, heavy load fluctuation and the dynamically changing system structure are inherent. Traditional power flow (PF) calculation based on Newton-Raphson (N-R) method frequently experiences non-convergence issues, resulting in severe ill-conditioned PF scenarios. It impedes accurate deduction and analysis of the operational state. This article offers a thorough examination of the TPSS under ill-conditioned PF scenarios and proposes an enhanced approach to PF calculation. First, a thorough analysis is conducted to identify the primary factors contributing to ill-conditioned PF under three typical circumstances: improper initial value, nonlinear characteristics, and large system scale. It uncovers the fundamental causes of ill-conditioned PF in urban rail systems, thereby providing opportunities for enhancing the PF algorithm. Subsequently, an improved PF algorithm is adopted that integrates the Levenberg-Marquardt (L-M) method. This approach leverages the convergence advantages of the L-M method near singular points to refine the iterative step update strategy in the N-R method. Finally, simulation and field test demonstrates that the proposed method not only ensures calculation accuracy but also significantly enhances convergence speed and simulation efficiency. This article contributes valuable perspectives and approaches for enhancing algorithms in PF calculation, thus facilitating the stable operation of urban rail systems.]]></description>
      <pubDate>Tue, 26 Aug 2025 15:34:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/2559287</guid>
    </item>
    <item>
      <title>Research on Coordinated Control Strategy of Energy Storage Type Railway Power Conditioner</title>
      <link>https://trid.trb.org/View/2402133</link>
      <description><![CDATA[In order to improve the power quality of high-speed railway traction power supply system and enhance the robust stability of railway power conditioner (RPC), a coordinated control strategy based on the energy storage system (ESS) integrated RPC (ESS-RPC) is proposed in this article. It is found that the dc impedance characteristics of the back-to-back system are different when the parameters of the ESS-RPC system are perturbed under conventional control, which will affect the dc voltage of the back-to-back system and then affect the power quality of the traction system. In this article, it is analyzed that the stability difference of the bidirectional power flow of ESS-RPC under parameter perturbation is due to the negative impedance of the dc terminal and the right shift of the dominant pole. After the analysis, a coordinated control strategy of ESS-RPC is proposed to solve this problem. The small-signal analysis of the ESS-RPC system under conventional control and coordinated control is carried out, respectively, and the robust stability of the two control strategies is judged by the Nyquist stability criterion. Simulation and experimental verification are carried out in the MATLAB/Simulink environment and semisimulation platform (Modeling Tech) to analyze the impact of the proposed coordinated control strategy on the power quality of the traction power supply system and verify the effectiveness and accuracy of this coordinated control strategy.]]></description>
      <pubDate>Mon, 26 Aug 2024 11:19:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2402133</guid>
    </item>
    <item>
      <title>Fault-Tolerant Method of Modular Railway Power Conditioner Based on DC Bus Voltage Regulation</title>
      <link>https://trid.trb.org/View/2364927</link>
      <description><![CDATA[With the development of high-speed electrified railways, many serious power quality problems have arisen and caused widespread concern. In order to achieve comprehensive management of power quality, a modular railway power conditioner (MRPC) has been applied to traction systems. Because of the presence of multiple submodules (SMs), the reliability of the equipment is, however, threatened as the number of SMs increases. In medium-voltage applications, system reliability can be improved by adding redundant SMs; however, when the redundant SMs run out, the reliability of the whole system cannot be guaranteed. Therefore, a fault-tolerant method based on dc bus voltage regulation is proposed to improve the reliability of MRPC by modulation signal reconstruction. The proposed method not only achieves fault ride-through to maintain normal operation and improves the SMs voltage stress on the opposite converter but also effectively improves the overmodulation. The effectiveness of the proposed method is verified by down-scale experiments.]]></description>
      <pubDate>Mon, 17 Jun 2024 09:38:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2364927</guid>
    </item>
    <item>
      <title>Research on DC Voltage Stability Control of Railway Power Conditioner Based on Impedance Matching Principle</title>
      <link>https://trid.trb.org/View/2364816</link>
      <description><![CDATA[When the railway power conditioner (RPC) is used to solve the power quality problem of the electrified railroad, the dc impedance will have a negative impedance characteristic during the bidirectional transmission of RPC power, and this negative impedance characteristic will affect the accuracy of RPC power compensation, cause the fluctuation of RPC dc bus voltage, and affect the effect of negative sequence current management on the grid side. In view of the above problems, this article proposes an RPC control strategy based on the impedance matching principle, which optimizes the negative impedance characteristics into positive impedance characteristics by the cooperative control of dc voltage and power, increases the phase angle margin of the system, improves the stability and dynamic performance of dc voltage under the bidirectional flow of RPC power, and improves the effect of grid-side negative sequence current management. First, this article performs small-signal modeling of the dc-side port impedance and analyzes its impedance characteristics. Second, the working principle of the RPC control strategy based on the impedance matching principle is analyzed. Finally, the proposed control strategy is effectively verified by building a simulation model and an experimental platform.]]></description>
      <pubDate>Mon, 20 May 2024 09:17:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2364816</guid>
    </item>
    <item>
      <title>Improved Power Sharing and Energy Management Platform in Microgrid Considering Stochastic Dynamic Behavior of the Electric Vehicles</title>
      <link>https://trid.trb.org/View/2223302</link>
      <description><![CDATA[In this study, an improved model of optimal power sharing and energy management as well as total harmonic distortion (THD) control in AC microgrids in order to control the voltage and frequency parameters by considering the random behavior of electric vehicles (EVs) is presented. The proposed model is developed based on the primary and secondary controller. The primary controller is planned with the purpose of optimal power-sharing, reduction of feeder's impedance mismatch and also THD reduction. The primary controller is modeled with the hybrid Event-Triggered approach and virtual impedance method. The secondary controller has been modeled using the particle swarm optimization (PSO) algorithm with the aim of reducing the power distribution error and optimizing the virtual impedance parameters, as well as considering the participation of EVs in the stochastic power flow equations. In addition to comparing the performance of the proposed model with conventional methods, it has also been compared with other meta-heuristic methods. The results of this have been verified in two software environments (MATLAB/Simulink) and experimental setup (dSPACE model 1202) in different scenarios and also the stability of the proposed model based on the Nyquist stability criterion, the Root Locus method and small signal analysis has been presented.]]></description>
      <pubDate>Fri, 01 Sep 2023 09:46:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2223302</guid>
    </item>
    <item>
      <title>Evaluation of an in situ QAM-based Power Line Communication system for lithium-ion batteries</title>
      <link>https://trid.trb.org/View/2035642</link>
      <description><![CDATA[Power Line Communication (PLC) is used to transmit high-fidelity data on internal cell characteristics from within instrumented cells to an external Battery Management System (BMS). Using PLC is beneficial, as it avoids the need for a complex and heavyweight wiring harness within a battery. The use of advanced modulation, such as Quadrature Amplitude Modulation (QAM), is considered here. The existing experimental results of lithium-ion cell impedance characteristics for frequencies of 100 kHz-200 MHz are exploited in order to create a realistic battery model. This model is used to determine the effectiveness and optimal properties of PLC with QAM, as a means of in situ battery communication for Battery Electric Vehicles (BEVs) in combination with a real-world dynamic drive profile. Simulations reveal that the performance of the PLC system is heavily dependent on the selected carrier frequency due to the significant changes in reactance and internal resistance of the lithium-ion cells tested. Furthermore, cells placed in parallel display a decreased performance compared with cells in series. The results highlight that the optimal carrier frequency for in situ QAM-based PLC for a lithium-ion battery system is 30 MHz, and that additional signal conditioning is required for 4-QAM and higher modulation orders.]]></description>
      <pubDate>Mon, 28 Nov 2022 10:56:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2035642</guid>
    </item>
    <item>
      <title>Electric Power Integration Schemes of the Hybrid Fuel Cells and Batteries-Fed Marine Vessels—An Overview</title>
      <link>https://trid.trb.org/View/1945480</link>
      <description><![CDATA[Transportation electrification is undergoing a significant transition toward the utilization of efficient and reliable energy sources and smart integration schemes, where this transitioning is continuously facing ever-tightening challenges in order to comply with the increased environmental regulations. Among the different means of transportation, global maritime transport is responsible for 2%–3% of global greenhouse gas (GHG) emissions, and it is predicted to increase to 17% by 2050 if no changes are adapted. Hence, the international maritime organization (IMO) has targeted to reach a 50% reduction in GHG emissions by 2050 compared to 2008. Hence, alternative energy sources shall be utilized in order to meet these strict GHG emissions reduction targets, where battery- and hydrogen-fed fuel cells can play a vital role in such aspects. Since the output of these two energy sources is unregulated dc voltage, their connection to the whole ship power system can be accomplished in several ways, where each way has its features, in addition to utilizing different power conditioning stages (PCSs), and these features are not well clarified and compared in the literature. Hence, this article presents an overview of the possible integration schemes that can be utilized in fuel cell- and battery-fed vessels, which is supported with a comparative assessment. This is also presented along with highlighting the state-of-the-art PCSs that are available in the market and can be utilized in these integration schemes within marine vessels. Such overview and comparative assessment are seen to be of significant importance and added value for researchers and developers in both the academic and industrial sides in order to accelerate the adoption of fuel cells in marine systems for zero-emission shipping.]]></description>
      <pubDate>Fri, 24 Jun 2022 17:07:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1945480</guid>
    </item>
    <item>
      <title>Interpolated Phase-Shifted PWM for Harmonics Suppression of Multilevel Hybrid Railway Power Conditioner in Traction Power Supply System</title>
      <link>https://trid.trb.org/View/1933681</link>
      <description><![CDATA[The railway power conditioner (RPC) based on the back-to-back modular multilevel converter (MMC), named multilevel hybrid RPC (MHRPC), was proposed to compensate for the power quality problems in traction power supply system (TPSS), such as negative sequence current, reactive power, and harmonics. Since TPSS is a 25 kV medium-voltage system, the phase-shifted pulsewidth modulation (PS-PWM) was chosen for MHRPC considering the number of submodules. However, the conventional PS-PWM suffers from higher distortion in output voltage or extra harmonics in circulating currents when applying to MHRPC. Various approaches were investigated to suppress harmonics, such as modified PWM methods, tailor-made filters, or additional transformers, but all increase control complexity or initial cost. In this article, a 2-D fast Fourier transform (FFT) harmonic model is developed to analyze how the phase displacement between stacks and legs impacts the harmonic distortion. Then an interpolated PS-PWM (IPS-PWM) is proposed, which sets the initial phase of carriers by coordinating four stacks of a single-phase MMC. It provides more output voltage stairs and eliminates the voltage unbalance states between the dc bus and two legs. Thus, MHRPC achieves better performance without extra hardware or increasing switching frequency. Simulation and experiment results verify the effectiveness of the proposed method.]]></description>
      <pubDate>Fri, 20 May 2022 09:32:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1933681</guid>
    </item>
    <item>
      <title>A Coupling Thermal Management Strategy Based on Fuzzy Control for a Range Extended Electric Vehicle Power System</title>
      <link>https://trid.trb.org/View/1929771</link>
      <description><![CDATA[An efficient power battery thermal management strategy under low-temperature conditions can effectively alleviate mileage anxiety associated with electric vehicles and improve environmental adaptability. This paper aims to propose a novel coupled thermal management strategy for range extended electric vehicles (REEVs) power systems containing a range extender and a power battery. First, a novel coupled thermal management structure for REEVs power system is designed. Sequentially, a fuzzy controller is developed based on analysis of control rules for different working conditions on the basis of the structure. Furthermore, the stability of the proposed strategy is strictly proven by Lyapunov’s stability theory and phase plane analysis. Finally, a coupled thermal management model is built in AMEsim, and co-simulation between MATLAB/Simulink and AMEsim is developed. The results show that the proposed coupled thermal management strategy efficiently reduces the warm-up time and the steady-state temperature error of the engine and power battery and improves the energy utilization efficiency.]]></description>
      <pubDate>Fri, 25 Mar 2022 12:08:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1929771</guid>
    </item>
    <item>
      <title>A partial compensation scheme for MMC-based railway cophase power supply</title>
      <link>https://trid.trb.org/View/1902903</link>
      <description><![CDATA[This paper presents a partial compensation scheme for V/v transformer cophase traction power supply in high-speed railway systems. The scheme compensates variable traction load current, and controls the current phase at the secondary side of the V/v transformer for power factor correction and negative sequence current reduction. To achieve this, the grid side current phase angles are optimized while satisfying the grid code on the power factor and voltage unbalance limits. The optimized phase angles are then used to design control references under varying load conditions. The compensation control action is updated regularly based on real-time measurements of the traction load, and the required currents are controlled by a 25-level single-phase back-to-back MMC power conditioner to achieve the compensation target. Static and dynamic load compensation performances are verified based on the simulation studies.]]></description>
      <pubDate>Mon, 28 Feb 2022 09:42:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1902903</guid>
    </item>
    <item>
      <title>Advancements in power conditioning units for electric vehicle applications: a review</title>
      <link>https://trid.trb.org/View/1862644</link>
      <description><![CDATA[Fuel cells are renowned for their direct energy conversion, quiet operation, fuel flexibility and zero CO₂ emissions. However, each fuel cell (FC) produces a very low output voltage of around 0.5-0.7 V. Therefore, it is necessary to design high gain DC-DC converters for boosting such low voltages either from a single FC or FC stack besides minimising the current ripples. Moreover, DC-AC converters are required to produce an AC voltage either for the single or three phase utility loads. This paper presents a review on various prominent DC-DC and DC-AC converter topologies. The performance of various DC-DC converter topologies is analysed in terms of number of components, converter switching frequency, galvanic isolation, power rating and efficiency. The salient features of potential DC-AC converters with low total harmonic distortion and high efficiency are presented. This paper is very useful for the design engineers in choosing the right topology.]]></description>
      <pubDate>Fri, 27 Aug 2021 14:58:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/1862644</guid>
    </item>
    <item>
      <title>Multi-Application Strategy Based on Railway Static Power Conditioner With Energy Storage System</title>
      <link>https://trid.trb.org/View/1844299</link>
      <description><![CDATA[With the rapid development of high-speed and heavy-load electrified railway, the peak impact and the regenerative braking energy content of traction load become increasingly significant, which has become an important problem affecting the construction and operation benefits of electrified railway. On the basis of comprehensively solving the power quality problems of electrified railway, a multi-application strategy based on the railway static power conditioner (RPC) with the energy storage system (ESS) is proposed in this paper to improve the economic benefits of the traction system. Through the implementation of the peak clipping and the recuperation and utilization of regenerative braking energy of traction load with the guidance of such strategy, the comprehensive economic benefits of the traction system can be improved. By analyzing the mathematical relationship between the comprehensive economic benefits and the parameters such as peak clipping rate and regenerative braking energy utilization rate of the system, an optimization model with the goal of maximizing the comprehensive economic benefits is established. Therefore, the optimal configuration capacity of the ESS is obtained. Finally, the experiments are carried out in MATLAB. The results show that, with the multi-application strategy, the peak load clipping and the recuperation and utilization of regenerative braking energy can be simultaneously realized. It is also demonstrated that the comprehensive economic benefits and environmental benefits can be improved while improving energy efficiency.]]></description>
      <pubDate>Tue, 25 May 2021 16:22:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1844299</guid>
    </item>
  </channel>
</rss>