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A Resilience Enhanced Secondary Control for AC Micro-grids

Xiao, J. (author), Wang, L. (author), Qin, Z. (author), Bauer, P. (author)

Communication-based distributed secondary control is deemed necessary to restore the state of islanding AC microgrids to set points. As its limited global information, the microgrids become vulnerable to cyber-attacks, which by falsifying the communicating singles, like the angular frequency, can disturb the power dispatch in the microgrids...

journal article 2024

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Low-Voltage dc System Building Blocks: Integrated Power Flow Control and Short Circuit Protection

Purgat, P. (author), Shekhar, A. (author), Qin, Z. (author), Bauer, P. (author)

Low-voltage direct current (LVdc) systems are a promising technology for systems with a high penetration of renewable sources and storage that operate with bidirectional power flow. In this article, a fundamental building block for LVdc is presented for different applications, such as charge controllers, voltage regulation in street-lighting...

journal article 2023

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A Gradient-Descent Optimization Assisted Gray-Box Impedance Modeling of EV chargers

Wang, L. (author), Qin, Z. (author), Bauer, P. (author)

Extracting an electric vehicle (EV) charger's input impedance with the analytical model (white-box approach) or the frequency sweep (black-box approach) is limited by the parameter confidentiality or the measurement noise, respectively. To overcome these challenges, a gradient-descent (GD) optimization-based gray-box modeling approach is...

journal article 2023

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ZVS-Optimized Constant and Variable Switching Frequency Modulation Schemes for Dual Active Bridge Converters

Lyu, D. (author), Straathof, C.A. (author), Soeiro, Thiago B. (author), Qin, Z. (author), Bauer, P. (author)

This paper proposes two modulation schemes for Dual Active Bridge (DAB) converters, with the aim of maximizing Zero Voltage Switching (ZVS) operation over a wide operational range. The first is a ZVS-optimized constant frequency modulation scheme, constructed based on the boundary conditions of ZVS operation. This scheme maximizes the number...

journal article 2023

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Power Disequilibrium Suppression in Bipolar DC Distribution Grids By Using A Series-Parallel Power Flow Controller

Liao, Jianquan (author), Zhou, Niancheng (author), Qin, Z. (author), Wang, Qianggang (author), Bauer, P. (author)

The unbalanced power between positive and negative poles in a bipolar DC distribution network (DC-DN) generates an unbalanced current at the neutral line, which enlarges the power losses of the system and the voltage deviation of DC loads. An unbalanced power suppression strategy based on a series-parallel power flow controller (SP-PFC) is...

journal article 2023

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Bipolar DC grids on ships: possibilities and challenges

Yadav, S. (author), Qin, Z. (author), Bauer, P. (author)

journal article 2022

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An online data driven fault diagnosis and thermal runaway early warning for electric vehicle batteries

Sun, S.Z. (author), Wang, Zhenpo (author), Liu, Peng (author), Qin, Z. (author), Chen, Yong (author), Han, Yang (author), Wang, Peng (author), Bauer, P. (author)

Battery fault diagnosis is crucial for stable, reliable, and safe operation of electric vehicles, especially the thermal runaway early warning. Developing methods for early failure detection and reducing safety risks from failing high energy lithium-ion batteries has become a major challenge for industry. In this article, a real-time early...

journal article 2022

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Guidelines for Stability Analysis of the DDSRF-PLL Using LTI and LTP Modelling in the Presence of Imbalance

Beloqui Larumbe, L. (author), Qin, Z. (author), Bauer, P. (author)

In this article, the Linear Time Invariant (LTI) and Linear Time Periodic (LTP) models of two different implementations of the DDSRF-PLL in the presence of voltage imbalance are derived analytically. The accuracy of the models is investigated with time domain simulations, frequency scans, and stability analysis. On top of this, a guideline for...

journal article 2022

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An Overview on Medium Voltage Grid Integration of Ultra-fast Charging Stations: Current Status and Future Trends

Ahmad, A. (author), Qin, Z. (author), Wijekoon, Thiwanka (author), Bauer, P. (author)

The emphasis on clean and green technologies to curtail greenhouse gas emissions due to fossil fuel-based economies has originated the shift towards electric mobility. As on-road electric vehicles (EVs) have shown exponential growth over the last decade, so have the charging demands. The provision of charging facilities from the low-voltage...

journal article 2022

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Design criteria of solid-state circuit breaker for low-voltage microgrids

Purgat, P. (author), Shah, Samad (author), van der Blij, N.H. (author), Qin, Z. (author), Bauer, P. (author)

Solid-state circuit breakers (SSCB) show great promise to become the key element in the protection of low-voltage direct current microgrids. SSCBs operate in the microsecond range and employ semi-conductor devices that have strict safe operation area limits. Therefore, the design of the SSCB needs to consider the effects of fault detection...

journal article 2021

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A Multiactive Bridge Converter With Inherently Decoupled Power Flows

Bandyopadhyay, S. (author), Purgat, P. (author), Qin, Z. (author), Bauer, P. (author)

Multiactive bridge converters (MAB) have become a widely-researched candidate for the integration of multiple renewable sources, storage, and loads for a variety of applications, from robust smart grids to more-electric aircraft. Connecting multiple dc ports reduces power conversion stress, improves efficiency, reduces material billing, and...

journal article 2021

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Stability Region Exploring of Shunt Active Power Filters Based on Output Admittance Modeling

Lei, Jintao (author), Qin, Z. (author), Li, Wuhua (author), Bauer, P. (author), He, Xiangning (author)

A shunt active power filter (SAPF) is coupled with load admittance in weak grid conditions, which poses a challenge to stability analysis. In this article, the admittance model of the SAPF is developed, which reveals the coupling mechanism between SAPF and load concisely and accurately. On top of that, the stability region of the system is...

journal article 2021

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Impedance Modeling for Three-Phase Inverters with Double Synchronous Reference Frame Current Controller in the Presence of Imbalance

Beloqui Larumbe, L. (author), Qin, Z. (author), Wang, L. (author), Bauer, P. (author)

This article presents a small-signal model for power-electronics converters that use a typical control structure in wind energy applications: the double synchronous reference frame current control. The article considers the presence of unbalanced currents and voltages, and analyzes their impact on the frequency couplings of the converter. In...

journal article 2021

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Coordination Control of Power Flow Controller and Hybrid DC Circuit Breaker in MVDC Distribution Networks

Liao, Jianquan (author), Zhou, Niancheng (author), Qin, Z. (author), Purgat, P. (author), Wang, Qianggang (author), Bauer, P. (author)

The two main challenges of medium voltage direct current (MVDC) distribution network are the flexible control of power flow (PF) and fault protection. In this paper, the power flow controller (PFC) is introduced to regulate the PF and inhibit the fault current during the DC fault. The coordination strategy of series-parallel PFC (SP-PFC) and...

journal article 2021

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Python Supervised Co-simulation for A Day-long Harmonic Evaluation of EV Charging

Wang, L. (author), Qin, Z. (author), Beloqui Larumbe, L. (author), Bauer, P. (author)

To accurately simulate electric vehicle DC fast chargers' (DCFCs') harmonic emission, a small time step, i.e., typically smaller than 10 μs, is required owing to switching dynamics. However, in practice, harmonics should be continuously assessed with a long duration, e.g., a day. A trade-off between accuracy and time efficiency thus exists. To...

journal article 2021

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Grid Impact of Electric Vehicle Fast Charging Stations: Trends, Standards, Issues and Mitigation Measures - An Overview

Wang, L. (author), Qin, Z. (author), Slangen, T (author), Bauer, P. (author), van Wijk, T (author)

With growing concern on climate change, widespread adoption of electric vehicles (EVs) is important. One of the main barriers to EV acceptance is range anxiety, which can be alleviated by fast charging (FC). The main technology constraints for enabling FC consist of high-charging-rate batteries, high-power-charging infrastructure, and grid...

journal article 2021

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Zero Voltage Switching Criteria of Triple Active Bridge Converter

Purgat, P. (author), Bandyopadhyay, S. (author), Qin, Z. (author), Bauer, P. (author)

Triple active bridge (TAB) as an isolated multiport converter is a promising integrated energy system for smart grids or electric vehicles. This article aims to derive and analyze zero voltage switching (ZVS) regions of TAB, in which both switching losses are reduced, and electromagnetic interference issues are mitigated. In the proposed...

journal article 2020

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Transformer Current Ringing in Dual Active Bridge Converters

Qin, Z. (author), Shen, Zhan (author), Blaabjerg, Frede (author), Bauer, P. (author)

In dual active bridge (DAB) converters, there can be transformer current ringing, especially when the transformer turns ratio is high. It is induced by high dv/dt generated by fast switching as well as the low impedance of the magnetic tank at the high-frequency range. To quantify the influence of the magnetic tank, its impedance model is...

journal article 2020

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Decoupling Control of Multiactive Bridge Converters Using Linear Active Disturbance Rejection

Bandyopadhyay, S. (author), Qin, Z. (author), Bauer, P. (author)

Multiactive bridge (MAB) converter is a promising solution for integrating multiple renewable sources, storage, and loads for various applications. However, the MAB converter is challenging to control due to the inherent coupling between the port power flows. To that end, this article presents a decoupling control strategy based on linear...

journal article 2020

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The long road to universal electrification: A critical look at present pathways and challenges

Narayan, N.S. (author), Vega Garita, V.E. (author), Qin, Z. (author), Popovic-Gerber, Jelena (author), Bauer, P. (author), Zeman, M. (author)

Nearly 840 million people still lack access to electricity, while over a billion more have an unreliable electricity connection. In this article, the three different electrification pathways-grid extension, centralized microgrids, and standalone solar-based solutions, such as pico-solar and solar home systems (SHS)-are critically examined...

journal article 2020