Lifetime extension of lithium-ion batteries with low-frequency pulsed current charging

IEEE Journal of Emerging and Selected Topics in Power Electronics

Published On 2021/11/23

The pulsed current has been proposed to achieve fast charging and extend the lifetime of lithium-ion (Li-ion) batteries. However, the optimal condition of the pulsed current is still inconclusive in previous studies. This article experimentally investigated the effect of the low-frequency positive pulsed current (PPC) charging on the lifetime and charging performance of Li-ion batteries. A two-stage degradation model of Li-ion batteries is developed to determine the inhibitory effect of the PPC on degradation mechanisms at different aging stages. Moreover, the changes in the internal resistance (IR) and the incremental capacity (IC) curve are provided to thoroughly explore the effects of the PPC on the degradation of Li-ion batteries. Compared with the traditional constant current (CC) charging, the lifetime, maximum rising temperature, and energy efficiency of the Li-ion batteries that were cycled by the PPC charging are …

Journal

IEEE Journal of Emerging and Selected Topics in Power Electronics

Published On

2021/11/23

Volume

11

Issue

1

Page

57-66

Authors

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

Position

Professor at

H-Index(all)

104

H-Index(since 2020)

72

I-10 Index(all)

0

I-10 Index(since 2020)

0

Citation(all)

0

Citation(since 2020)

0

Cited By

0

Research Interests

Power Electronics

Smart Batteries

AI

University Profile Page

Daniel Stroe

Daniel Stroe

Aalborg Universitet

Position

Head of Battery Storage Systems Research Programme at

H-Index(all)

49

H-Index(since 2020)

46

I-10 Index(all)

0

I-10 Index(since 2020)

0

Citation(all)

0

Citation(since 2020)

0

Cited By

0

Research Interests

Lithium-ion Batteries

Energy Storage

Electric Vehicles

Renewable Energy

Energy Management

University Profile Page

Wenjie Liu

Wenjie Liu

Aalborg Universitet

Position

H-Index(all)

12

H-Index(since 2020)

11

I-10 Index(all)

0

I-10 Index(since 2020)

0

Citation(all)

0

Citation(since 2020)

0

Cited By

0

Research Interests

power electronics

University Profile Page

Other Articles from authors

Daniel Stroe

Daniel Stroe

Aalborg Universitet

Data in Brief

Dataset of lithium-ion battery degradation based on a forklift mission profile for state-of-health estimation and lifetime prediction

Lithium-ion (Li-ion) batteries are becoming an increasingly integral part of modern society, through consumer electronics, stabilisation of the electric grid, and electric vehicles. However, Lithium-ion batteries degrade in effectiveness over time; a degradation which is extremely dependent on the usage of the battery. Therefore, to study how a battery cell degrades under dynamic conditions, a realistic load profile was constructed based on the operation of forklifts. This profile was used to age three Lithium-ion battery cells at 45, 40, and 35°C and the response of the cells was measured on a second-by-second basis. Periodically the ageing was halted to perform a reference test of the cells allowing for the tracking of their degradation.

Daniel Stroe

Daniel Stroe

Aalborg Universitet

On the Use of Randomly Selected Partial Charges to Predict Battery State-of-Health

As society becomes more reliant on Lithium-ion (Li-ion) batteries, state-of-health (SOH) estimation will need to become more accurate and reliable. Therefore, SOH modelling is in the process of shifting from using simple and continuous charge/discharge profiles, to more dynamic profiles constructed to mimic real operation, when ageing the Li-ion batteries. However, in most cases, when ageing the batteries, the same exact profile is just repeated until the battery reaches its end-of-life. Using data from batteries aged in this fashion to build a model, there is a very real possibility that the model will rely on the built-in repetitiveness of the profile. Therefore, this work will examine the dependence of the performance of a multiple linear regression on the number of charges used to train the model, and their location within the profile used to age the batteries. The investigation shows that it is possible to build models using randomly selected partial charges while still reaching errors as low as 0.5%. Furthermore, it shows that only two randomly sampled partial charges are needed to achieve errors of less than 1%. Lastly, as the number of randomly sampled partial charges used to create the model increases, then the dependence on particular partial charges tends to decrease.

Daniel Stroe

Daniel Stroe

Aalborg Universitet

Batteries

Lithium-Ion Supercapacitors and Batteries for Off-Grid PV Applications: Lifetime and Sizing

The intermittent nature of power generation from photovoltaics (PV) requires reliable energy storage solutions. Using the storage system outdoors exposes it to variable temperatures, affecting both its storage capacity and lifespan. Utilizing and optimizing energy storage considering climatic variations and new storage technologies is still a research gap. Therefore, this paper presents a modified sizing algorithm based on the Golden Section Search method, aimed at optimizing the number of cells in an energy storage unit, with a specific focus on the unique conditions of Denmark. The considered energy storage solutions are Lithium-ion capacitors (LiCs) and Lithium-ion batteries (LiBs), which are tested under different temperatures and C-rates rates. The algorithm aims to maximize the number of autonomy cycles—defined as periods during which the system operates independently of the grid, marked by intervals between two consecutive 0% State of Charge (SoC) occurrences. Testing scenarios include dynamic temperature and dynamic load, constant temperature at 25 °C, and constant load, considering irradiation and temperature effects and cell capacity fading over a decade. A comparative analysis reveals that, on average, the LiC storage is sized at 70–80% of the LiB storage across various scenarios. Notably, under a constant-temperature scenario, the degradation rate accelerates, particularly for LiBs. By leveraging the modified Golden Section Search algorithm, this study provides an efficient approach to the sizing problem, optimizing the number of cells and thus offering a potential solution for energy storage in off-grid PV systems.

Daniel Stroe

Daniel Stroe

Aalborg Universitet

Journal of Energy Storage

Identification of the aging state of lithium-ion batteries via temporal convolution network and self-attention mechanism

Deep learning methods have been widely used for battery aging state estimation with either manual or automatic features, while the contribution of multi-source features is rarely considered. To solve this problem, a hybrid method is proposed to combine the manual and automatic features based on a temporal convolution network (TCN) and a self-attention mechanism (SA). Specifically, the local voltage, capacity, and incremental capacity are manually extracted as battery aging features. Then, for extracting automatic features, TCN employs dilated convolution to capture the capacity regeneration phenomenon during battery degradation. Considering the contribution of multi-source features, we use SA to fuse the obtained manual and automatic features. Finally, the available capacity and remaining useful life of the battery are predicted using a fully connected neural network on one dataset from our lab, the Oxford …

Daniel Stroe

Daniel Stroe

Aalborg Universitet

Battery state-of-health estimation using machine learning

Over the years, lithium–ion batteries have developed as a key enabling technology for the green transition. Although many of these batteries’ characteristics, such as energy density, power capability, and cost, have gradually improved, uncertainties remain concerning their performance over their lifetimes. Thus, to ensure reliable and efficient battery operation, the battery's available performance, known as its state of health (SOH), must be known at every moment. This chapter introduces the most common battery SOH estimation methods, from direct measurements to deep neural networks, discussing their key performance metrics, advantages, and drawbacks.

Daniel Stroe

Daniel Stroe

Aalborg Universitet

Advanced Energy Materials

Unravelling the Mechanism of Pulse Current Charging for Enhancing the Stability of Commercial LiNi0.5Mn0.3Co0.2O2/Graphite Lithium‐Ion Batteries

The key to advancing lithium‐ion battery (LIB) technology, particularly with respect to the optimization of cycling protocols, is to obtain comprehensive and in‐depth understanding of the dynamic electrochemical processes during battery operation. This work shows that pulse current (PC) charging substantially enhances the cycle stability of commercial LiNi0.5Mn0.3Co0.2O2 (NMC532)/graphite LIBs. Electrochemical diagnosis unveils that pulsed current effectively mitigates the rise of battery impedance and minimizes the loss of electrode materials. Operando and ex situ Raman and X‐ray absorption spectroscopy reveal the chemical and structural changes of the negative and positive electrode materials during PC and constant current (CC) charging. Specifically, Li‐ions are more uniformly intercalated into graphite and the Ni element of NMC532 achieves a higher energy state with less Ni─O bond length variation …

Daniel Stroe

Daniel Stroe

Aalborg Universitet

Thermal state monitoring of lithium-ion batteries: Progress, challenges, and opportunities

Transportation electrification is a promising solution to meet the ever-rising energy demand and realize sustainable development. Lithium-ion batteries, being the most predominant energy storage devices, directly affect the safety, comfort, driving range, and reliability of many electric mobilities. Nevertheless, thermal-related issues of batteries such as potential thermal runaway, performance degradation at low temperatures, and accelerated aging still hinder the wider adoption of electric mobilities. To ensure safe, efficient, and reliable operations of lithium-ion batteries, monitoring their thermal states is critical to safety protection, performance optimization, as well as prognostics, and health management. Given insufficient onboard temperature sensors and their inability to measure battery internal temperature, accurate and timely temperature estimation is of particular importance to thermal state monitoring. Toward …

Daniel Stroe

Daniel Stroe

Aalborg Universitet

State-of-energy balancing control with cascaded H-bridge for second-life batteries

Battery energy storage systems (BESS) are fre-quently utilized to support the power grid. Second-Life batteries (SLBs) are considered as a potential solution to reduce the cost of BESS in stationary applications. However, using SLBs has certain challenges due to the non-uniform State-of-Charge (SOC) and State-of-Health (SOH) among the battery modules. This study examines two control strategies for a cascaded H-bridge (CHB) topology used for BESS applications. The possibilities for flexible control of the BESS are enabled by employing a CHB topology. By utilizing the CHB topology, each battery module can be individually charged and discharged. Two battery energy management system (BEMS) techniques are proposed based on the batteries' State-of-Energy (SOE): 1) continuous and 2) discrete balancing techniques. The experimental tests demonstrate the advantages of the proposed solutions in terms of …

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

IEEE Transactions on Industrial Electronics

Health Prediction for Lithium-Ion Batteries Under Unseen Working Conditions

Battery health prediction is significant while challenging for intelligent battery management. This article proposes a general framework for both short-term and long-term predictions of battery health under unseen dynamic loading and temperature conditions using domain-adaptive multitask learning (MTL) with long-term regularization. First, features extracted from partial charging curves are utilized for short-term state of health predictions. Then, the long-term degradation trajectory is directly predicted by recursively using the predicted features within the multitask framework, enhancing the model integrity and lowering the complexity. Then, domain adaptation (DA) is adopted to reduce the discrepancies between different working conditions. Additionally, a long-term regularization is introduced to address the shortcoming that arises when the model is extrapolated recursively for future health predictions. Thus, the short …

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

IEEE/ASME Transactions on Mechatronics

Online Sensorless Temperature Estimation of Lithium-Ion Batteries Through Electro-Thermal Coupling

Owing to the nonnegligible impacts of temperature on the safety, performance, and lifespan of lithium-ion batteries, it is essential to regulate battery temperature to an optimal range. Temperature monitoring plays a fundamental role in battery thermal management, yet it is still challenged by limited onboard temperature sensors, particularly in large-scale battery applications. As such, developing sensorless temperature estimation is of paramount importance to acquiring the temperature information of each cell in a battery system. This article proposes an estimation approach to obtain the cell temperature by taking advantage of the electrothermal coupling effect of batteries. An electrothermal coupled model, which captures the interactions between the electrical and the thermal dynamics, is established, parameterized, and experimentally validated. A closed-loop observer is then designed based on this coupled model …

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

Artificial Intelligence-Based State-of-Health Estimation of Lithium-Ion Batteries

The State of Health (SOH) estimation for automotive batteries is currently assessed with different techniques which may involve long testing procedure or require costly hardware to be implemented. This paper aims at contributing to this domain by exploiting the response of a lead-acid battery with respect to a short-term current profile using an Artificial Neural Network (ANN) classifier for SOH estimation. The method is applicable onboard the vehicle and no additional instrumentation is required on the retained vehicle. The design and validation of a SOH method with a short-term current profile using Artificial Intelligence (AI) in lead-acid batteries, which are commonly used in heavy-duty vehicles for cranking and cabin systems, are presented. The paper validates the considered approach with experimental data, which are representative of actual vehicle operations. In detail, the paper describes the retained …

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

arXiv preprint arXiv:2402.07777

Novel Low-Complexity Model Development for Li-ion Cells Using Online Impedance Measurement

Modeling of Li-ion cells is used in battery management systems (BMS) to determine key states such as state-of-charge (SoC), state-of-health (SoH), etc. Accurate models are also useful in developing a cell-level digital-twin that can be used for protection and diagnostics in the BMS. In this paper, a low-complexity model development is proposed based on the equivalent circuit model (ECM) of the Li-ion cells. The proposed approach uses online impedance measurement at discrete frequencies to derive the ECM that matches closely with the results from the electro-impedance spectroscopy (EIS). The proposed method is suitable to be implemented in a microcontroller with low-computational power, typically used in BMS. Practical design guidelines are proposed to ensure fast and accurate model development. Using the proposed method to enhance the functions of a typical automotive BMS is described. Experimental validation is performed using large prismatic cells and small-capacity cylindrical cells. Root-mean-square error (RMSE) of less than 3\% is observed for a wide variation of operating conditions.

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

IEEE Transactions on Industrial Informatics

A Battery Digital Twin From Laboratory Data Using Wavelet Analysis and Neural Networks

Lithium-ion (Li-ion) batteries are the preferred choice for energy storage applications. Li-ion performances degrade with time and usage, leading to a decreased total charge capacity and to an increased internal resistance. In this article, the wavelet analysis is used to filter the voltage and current signals of the battery to estimate the internal complex impedance as a function of state of charge (SoC) and state of health (SoH). The collected data are then used to synthesize a battery digital twin (BDT). This BDT outputs a realistic voltage signal as a function of SoC and SoH inputs. The BDT is based on feedforward neural networks trained to simulate the complex internal impedance and the open-circuit voltage generator. The effectiveness of the proposed method is verified on the dataset from the prognostics data repository of NASA.

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

IEEE Transactions on Industry Applications

Small-Sample-Learning-Based Lithium-Ion Batteries Health Assessment: An Optimized Ensemble Framework

Machine Learning is widely studied in battery state of health (SOH) estimation due to its advantage in establishing the non-linear mapping between measurements and SOH. However, the requirement of a big dataset and the lack of robustness limit the practical application, especially in small sample learning. To tackle these challenges, an optimal ensemble framework called BaggELM (bagging extreme learning machine) is proposed for battery SOH estimation. Specifically, the required dataset is reduced by optimizing the input voltage and the hyperparameters of the BaggELM algorithm. Moreover, a statistical post-processing method is used to aggregate multiple ELMs, and the final estimate is determined by the maximum probability density value. As a result, the effects of random parameterization of ELM and the training data size on SOH estimation are suppressed, thus improving the robustness and accuracy of …

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

Intelligent Cell Balancing Control for Lithium-Ion Battery Packs

This study introduces a balancing control strategy that employs an Artificial Neural Network (ANN) to ensure State of Charge (SOC) balance across lithium-ion (Li-ion) battery packs, consistent with the framework of smart battery packs. The model targets a battery pack consisting of cells with diverse characteristics, reflecting real-world heterogeneous conditions. A fundamental aspect of this approach is the ability to bypass individual cells optimally. This key feature stops current flow to and from the cell, allowing it to rest and cool off while avoiding charging or discharging cycles. The implementation of ANN enables adaptive and dynamic management of SOC, which is essential for optimizing performance and extending the lifespan of battery packs. The results demonstrate the effectiveness of the proposed ANN-based balancing strategy in SOC balancing, demonstrating its potential as a critical solution in enhancing battery management systems for electric vehicles.

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

Grid Impedance Shaping for Grid-Forming Inverters: A Soft Actor-Critic Deep Reinforcement Learning Algorithm

This paper proposed an advanced method for adjusting grid impedance in grid-forming inverters, utilizing the Soft Actor-Critic Deep Reinforcement Learning (SAC-DRL) algorithm. The approach contains a flexible strategy for controlling virtual impedance, supported by an equivalent grid impedance estimator. This facilitates accurate modifications of virtual impedance based on the grid’s X/R ratio and the converter’s power capacity, aiming to optimize power flow and maintain grid stability. A unique feature of this methodology is the division of virtual reactance into two segments: one adhering to standard control protocols and the other designated for precision enhancement via the SAC-DRL method. This strategy introduces a layer of intelligence to the system, strengthening its resilience against fluctuations in grid impedance. Experimental validations, executed on a laboratory setup, verify the robustness of this approach, highlighting its potential to significantly improve intelligent power grid management practices.

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

Electric vehicle battery charging strategy

As a key enabler for transportation electrification and a contributor toward the net-zero carbon future, battery plays a pivotal role in determining the energy management performance of electric vehicles. Technical challenges facing the development of advanced automotive battery charging arise from various contradictory objectives, immeasurable internal states, and hard constraints. This chapter presents a critical introduction to the state-of-the-art charging strategies for the electric vehicle battery and their key enabling technologies. Specifically, battery charging solutions for electric vehicles are first classified and discussed. Then, the battery models on which these solutions rest are stated, the related charging frameworks are summarized, and the advantages and drawbacks of the adopted technologies are discussed. Suggestions for overcoming the limitations of the discussed charging strategies are proposed …

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

Thermal state monitoring of lithium-ion batteries: Progress, challenges, and opportunities

Transportation electrification is a promising solution to meet the ever-rising energy demand and realize sustainable development. Lithium-ion batteries, being the most predominant energy storage devices, directly affect the safety, comfort, driving range, and reliability of many electric mobilities. Nevertheless, thermal-related issues of batteries such as potential thermal runaway, performance degradation at low temperatures, and accelerated aging still hinder the wider adoption of electric mobilities. To ensure safe, efficient, and reliable operations of lithium-ion batteries, monitoring their thermal states is critical to safety protection, performance optimization, as well as prognostics, and health management. Given insufficient onboard temperature sensors and their inability to measure battery internal temperature, accurate and timely temperature estimation is of particular importance to thermal state monitoring. Toward …

Daniel Stroe

Daniel Stroe

Aalborg Universitet

Applied Energy

Optimal battery thermal management for electric vehicles with battery degradation minimization

The control of a battery thermal management system (BTMS) is essential for the thermal safety, energy efficiency, and durability of electric vehicles (EVs) in hot weather. To address the battery cooling optimization problem, this paper utilizes dynamic programming (DP) to develop an online rule-based control strategy. Firstly, an electrical–thermal-aging model of the LiFePO 4 battery pack is established. A control-oriented onboard BTMS model is proposed and verified under different speed profiles and temperatures. Then in the DP framework, a cost function consisting of battery aging cost and cooling-induced electricity cost is minimized to obtain the optimal compressor power. By exacting three rules” fast cooling, slow cooling, and temperature-maintaining” from the DP result, a near-optimal rule-based cooling strategy, which uses as much regenerative energy as possible to cool the battery pack, is proposed for …

Remus Teodorescu

Remus Teodorescu

Aalborg Universitet

Reliability Engineering & System Safety

Predictive health assessment for lithium-ion batteries with probabilistic degradation prediction and accelerating aging detection

Predictive health assessment is of vital importance for smarter battery management to ensure optimal and safe operations and thus make the most use of battery life. This paper proposes a general framework for battery aging prognostics in order to provide the predictions of battery knee, lifetime, state of health degradation, and aging rate variations, as well as the assessment of battery health. Early information is used to predict knee slope and other life-related information via deep multi-task learning, where the convolutional-long-short-term memory-bayesian neural network is proposed. The structure is also used for online state of health and degradation rate predictions for the detection of accelerating aging. The two probabilistic predicted boundaries identify the accelerating aging regions for battery health assessment. To avoid wrong and premature alarms, the empirical model is used for data preprocessing and …

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University of Georgia

IEEE Journal of Emerging and Selected Topics in Power Electronics

A Four-layer Cyber-physical Security Model for Electric Machine Drives considering Control Information Flow

Despite the IEEE Power Electronics Society (PELS) establishing Technical Committee 10 on Design Methodologies with a focus on the cyber-physical security of power electronics systems, a holistic design methodology for addressing security vulnerabilities remains underdeveloped. This gap largely stems from the limited integration of computer science and power/control engineering studies in this interdisciplinary field. Addressing the inadequacy of unilateral cyber or control perspectives, this paper presents a novel four-layer cyber-physical security model specifically designed for electric machine drives. Central to this model is the innovative Control Information Flow (CIF) model, residing within the control layer, which serves as a pivotal link between the cyber layer’s vulnerable resources and the physical layer’s state-space models. By mapping vulnerable resources to control variable space and tracing attack …

Hao Feng

Hao Feng

North Carolina State University

IEEE Journal of Emerging and Selected Topics in Power Electronics

Condition Monitoring of Discrete Power Devices: A Data-Driven Approach with Stress Quantification and Mold Temperature Sensing

Discrete power devices are used in a wide range of applications some of which would benefit from device condition monitoring (CM). This paper presents a data-driven method to online evaluate the health status of the discrete devices. It is based on the detection of mold temperature by only one thermocouple, offering low cost and non-intrusive features. The approach looks into five electrical stressors and uses existing sensors to track the load variation, enabling adaptation to both linear or nonlinear load conditions of the inverter system; no additional sampling of electrical signal is required. Under the tracked electrical stresses, a back-propagation neural network (BPNN) is employed to establish the correlation between mold temperature and aging status. The overall design and implementation process, including the hardware design, model training and CM integration, are demonstrated on a 7.5 kW T-type Neutral …

Mohamad Ghaffarian Niasar

Mohamad Ghaffarian Niasar

Technische Universiteit Delft

IEEE Journal of Emerging and Selected Topics in Power Electronics

Optical Detection and Characteristics of PCB Partial Discharge in More-electric Aircraft under Square Wave Voltage

More electric aircraft (MEA) is an important direction for future aircraft development. The printed circuit boards (PCB) of power electronics equipment in MEA operates in a complex environment of low air pressure, square wave voltage, compact layout and strong electromagnetic interference, which makes the PCB more prone to partial discharge (PD). However, the effective detection method and related discharge characteristics for PCB PD under square wave voltage are still unclear. Therefore, this paper proposes a PCB PD detection method based on fluorescent optical fiber, which has good anti-electromagnetic interference ability. The PD characteristics of the PCB with three typical structures under three air pressures are studied, including PD non-breakdown characteristics, changes in optical pulse amplitude and pulse repetition rate during PD aging, PD breakdown path analysis and PCB surface electric field …

Haoze Luo

Haoze Luo

Aalborg Universitet

IEEE Journal of Emerging and Selected Topics in Power Electronics

A 3-D Temperature-Dependent Thermal Model of IGBT Modules for Electric Vehicle Application Considering Various Boundary Conditions

With the development of power electronic converters (PECs), the thermal properties of high-power insulated gate bipolar transistor (IGBT) module are of significant importance in the reliability analysis, thermal design, and management of PECs. However, the present commonly used three-dimensional (3-D) thermal network model, still has limitations in accurately obtaining the junction temperature of IGBT modules. Particularly under high-temperature conditions, its performance is not ideal. This paper proposes a 3-D thermal network model considering the temperature effect of constituent materials, which has been efficiently obtained using four sets of finite element method (FEM) transient thermal simulation. By employing a two-step extraction (TPE) method, the thermal parameters including the conductance and capacitance of crucial nodes are fully identified based on the reconstruction matrix of virtual temperature …

Zhang Xin

Zhang Xin

Zhejiang University

IEEE Journal of Emerging and Selected Topics in Power Electronics

STAR: One-Stop Optimization for Dual Active Bridge Converter with Robustness to Operational Diversity

In the fast-evolving landscape of artificial intelligence (AI) technology, significant strides have been taken to streamline and automate the design of power converters. However, prevalent limitations in existing AI-aided design approaches underscore the need for innovative solutions. Firstly, a lack of robustness to operational diversity hampers adaptability, requiring a complete AI model building from scratch when conditions, modulation strategies, or performance metrics for evaluation change. Secondly, the challenging trade-off between dataset size and design accuracy prolongs data acquisition through hardware experiments. Thirdly, the industry faces reluctance to adopt pure data-driven approaches due to their inherent lack of fundamental and explainable circuit insights. Addressing these challenges, this paper introduces a one-stop optimization methodology, the STAR methodology, tailored for designing …

王奎, Kui Wang

王奎, Kui Wang

Tsinghua University

IEEE Journal of Emerging and Selected Topics in Power Electronics

A Simple Method for Common-Mode Voltage Reduction and Neutral-Point Potential Balance of Back-to-Back Three-Level NPC Converters

Common-mode voltage (CMV) is harmful to the motor bearing in converter systems. In order to reduce the high amplitude CMV and balance the neutral-point potential (NPP) of back-to-back three-level neutral-point clamped (NPC) converters, a simple dual-side zero-sequence voltage (ZSV) injection method based on carrier-based pulse-width modulation (CBPWM) is proposed in this paper. Two optimal ZSVs are injected into the rectifier side and inverter side respectively, which can reduce the amplitude of CMV to 1/6 of the DC-bus voltage and balance the NPP effectively at the same time. This proposed method based on CBPWM is much easier to be implemented compared with the SVPWM-based method. Experimental results demonstrate the effectiveness of the proposed method.

Ranjan Kumar Behera

Ranjan Kumar Behera

Indian Institute of Technology Patna

IEEE Journal of Emerging and Selected Topics in Power Electronics

Advance Controller for Power Quality and Performance Improvement of Grid-Connected Single-Phase Rooftop PVS

This paper presents a robust controller for a single-phase single-stage photovoltaic systems (PVS) converter connected to the grid. A high efficiency single-phase single-stage converters are prone to double frequency oscillations and DC-link voltage fluctuations when connected to a PVS. It introduces phase shift and injects harmonics in the grid current. To address this issue, a robust DC-link voltage controller is proposed. It can achieve fast transient response with lesser overshoot under power intermittency and grid side disturbances. A filter is employed to reduce the impact of switching frequency, however, a Lyapunov-based inner loop current controller with an active damping method minimizes the effect of resonance and achieves system stability. The proposed composite controller guarantees the system robustness against grid disturbances and parameter uncertainties. In addition, it eliminates the effect of …

Zhedong Ma

Zhedong Ma

University of Florida

IEEE Journal of Emerging and Selected Topics in Power Electronics

Integration of Near Field Communication (NFC) Antenna and Wireless Charging Coil for Portable Electronic Products

In portable electronics applications, although near-field communication (NFC) works at 13.56MHz and wireless charging (WLC) works at from 87kHz-205kHz, the efficient integration of NFC antenna coil and WLC receiver coil can reduce the volume and cost of portable electronic equipment. In this paper, a novel NFC and WLC coil integration technology is proposed based on the wide-band impedance models of the coil. The circuit model of the proposed integrated coil is developed. Based on the developed model, the technique to improve NFC inductance’s effective frequency range is investigated. Furthermore, the physical meaning of the NFC inductance and its magnetic field distribution is analyzed. Finally, the proposed integrated coil is experimentally validated.