Josep Pou

Josep Pou

Nanyang Technological University

H-index: 67

Asia-Singapore

About Josep Pou

Josep Pou, With an exceptional h-index of 67 and a recent h-index of 53 (since 2020), a distinguished researcher at Nanyang Technological University, specializes in the field of Power Electronics, Multilevel Converters, Renewable Energy, Energy Storage.

His recent articles reflect a diverse array of research interests and contributions to the field:

Constant Current Precharging Algorithm for Solid State Power Controllers

Comparison of adaptive P/ω droop strategies for intermittent energy sources in emergency islanded operation

Virtual Arm Impedance Emulation and Stability Improvement in Modular Multilevel Converters

Asymmetrical-Bidirectional Input-Series–Output-Parallel Modular DC–DC Converter in DC Distribution Grids With Renewables

Reactive Power Distribution in the Cascaded H-Bridge Converter With Unbalanced Submodule Active Power for Capacitance Reduction

A Generalized Derivation Method of Tree-Type Active Neutral-Point-Clamped Multilevel Topologies

Minimum Voltage Operation of Cascaded H-Bridge StatComs Using Discontinuous Modulation

Deep Reinforcement Learning-Enabled Distributed Uniform Control for a DC Solid State Transformer in DC Microgrid

Josep Pou Information

University

Nanyang Technological University

Position

___

Citations(all)

21415

Citations(since 2020)

11381

Cited By

14215

hIndex(all)

67

hIndex(since 2020)

53

i10Index(all)

227

i10Index(since 2020)

189

Email

University Profile Page

Nanyang Technological University

Josep Pou Skills & Research Interests

Power Electronics

Multilevel Converters

Renewable Energy

Energy Storage

Top articles of Josep Pou

Constant Current Precharging Algorithm for Solid State Power Controllers

Authors

Mridul Marwaha,Josep Pou,Chandana Gajanayake,Devinda Molligoda,Kuntal Satpathi,Yang Yu,Mohamed Halick Mohamed Sathik,Anh-Vu Ho,Amit Kumar Gupta,Yu Zeng

Journal

IEEE Transactions on Industrial Electronics

Published Date

2024/1/24

Semiconductor-based solid-state power controllers (SSPCs) are a promising solution for dc system protection. During the connection of capacitive loads there is an inrush current because of zero initial energy in the capacitor, which can cause damage to the system. One of the main challenges of SSPCs is to suppress the current and voltage overshoot during precharging. In most of the precharging methods, additional circuitry is required, which adds weight, size, and complexity to the system. In this article, a constant current precharging algorithm is proposed. The main semiconductor device is utilized for precharging instead of adding an auxiliary circuit, thus reducing the required number of components. In addition, the proposed algorithm has a higher adaptability to the change of system parameters. Moreover, it is easily implementable to a wide range of semiconductor devices. Analytical evaluations are …

Comparison of adaptive P/ω droop strategies for intermittent energy sources in emergency islanded operation

Authors

Candelaria Utrilla,Vincent Debusschere,Jérôme Buire,Hossein Dehghani Tafti,Josep Pou,Nouredine Hadjsaid

Journal

International Journal of Electrical Power & Energy Systems

Published Date

2024/6/1

Islanded operation is a key tool to improve the reliability and operational resilience of distribution grids. To enable islanded operation with minimal hardware changes, it is convenient to operate already installed PV units in droop-controlled grid-forming mode. This paper analyzes the main adaptive strategies that allow to implement the P/ω droop principle in double-stage units interfacing intermittent energy sources. The advantages and unwanted behaviors of each strategy are illustrated through a thorough simulation-based evaluation, which leads to a set of guidelines for the design of novel improved adaptive P/ω droop strategies.

Virtual Arm Impedance Emulation and Stability Improvement in Modular Multilevel Converters

Authors

Ye Zhu,Shan Jiang,Josep Pou,Georgios Konstantinou

Journal

IEEE Transactions on Power Electronics

Published Date

2024/1/9

The arm impedance in a modular multilevel converter (MMC) influences both the internal dynamics and the converter impedance, significantly impacting the overall system stability. This article proposes a damping method with virtual arm impedance to suppress the small-signal oscillations caused by impedance interactions and improve the MMC stability. The virtual arm impedance, including both a resistance and a reactance component, is emulated based on the common-mode (CM) second-harmonic circulating current, which is injected to optimize the capacitor voltages of MMCs. Different from existing virtual impedance methods, the steady-state operation of the MMC is not influenced by the CM virtual arm impedance. It is shown that the virtual reactance of the same impedance has a better damping effect, compared with the virtual resistance. Selection guidelines of virtual reactance are also provided …

Asymmetrical-Bidirectional Input-Series–Output-Parallel Modular DC–DC Converter in DC Distribution Grids With Renewables

Authors

Changjiang Sun,Shuai Wang,Josep Pou,Chandana Jayampathi Gajanayake,Amit Kumar Gupta

Journal

IEEE Transactions on Power Electronics

Published Date

2024/4

Asymmetrical-Bidirectional Input-Series–Output-Parallel Modular DC–DC Converter in DC Distribution Grids With Renewables - NASA/ADS Now on home page ads icon ads Enable full ADS view NASA/ADS Asymmetrical-Bidirectional Input-Series–Output-Parallel Modular DC–DC Converter in DC Distribution Grids With Renewables Sun, Changjiang ; Wang, Shuai ; Pou, Josep ; Gajanayake, Chandana Jayampathi ; Gupta, Amit Kumar Abstract Publication: IEEE Transactions on Power Electronics Pub Date: April 2024 DOI: 10.1109/TPEL.2023.3329775 Bibcode: 2024ITPE...39.3943S full text sources Publisher | © The SAO/NASA Astrophysics Data System adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A NASA logo Smithsonian logo Resources About ADS ADS Help What's New Careers@ADS Social @adsabs ADS …

Reactive Power Distribution in the Cascaded H-Bridge Converter With Unbalanced Submodule Active Power for Capacitance Reduction

Authors

Gaowen Liang,Ezequiel Rodriguez,Yu Zeng,Glen Farivar,Hin Sang Lam,Huawei Yuan,Josep Pou

Journal

IEEE Transactions on Industrial Electronics

Published Date

2024/3/6

In the operation of the cascaded H-bridge converter-based battery energy storage system, the active power of each phase can be unevenly distributed among the submodules (SMs) for various reasons. In such conditions, conventional control methods yield unbalanced capacitor voltage ripple magnitudes among the SMs due to the active power disparity. Consequently, the capacitor voltage ripples will be relatively large in some SMs, increasing the capacitance requirement of the system. This article develops a method to balance the capacitor voltage ripples by coordinating the reactive power distribution with the active power distribution among the SMs. Accordingly, the proposed method can effectively reduce the capacitance requirement, as verified in both simulations and experiments. In one case study, the proposed methods can reduce the capacitance requirement by more than 50% compared with the …

A Generalized Derivation Method of Tree-Type Active Neutral-Point-Clamped Multilevel Topologies

Authors

Kui Wang,Mingzhe Wu,Zedong Zheng,Josep Pou,Jose Rodríguez,Yun Wei Li,Yongdong Li

Journal

IEEE Transactions on Power Electronics

Published Date

2024/2/13

Improving the power density of multilevel converters is a crucial task, particularly in high-power applications where the volume of passive components is significant. To achieve a high number of voltage levels with minimal device count, this article presents a novel and generalized derivation method for a new family of tree-type active neutral-point-clamped (TANPC) multilevel topologies. By utilizing the two-level bridge and three-level neutral-point pilot bridge as fundamental cells, the proposed method enables the extension of output voltage levels in a simple and straightforward way. Each derived TANPC topology is equivalent to a single-pole multi-throw switch without the need for flying capacitors, where n+1 voltage levels can be generated with only 2n active switches. The related pulsewidth modulation and neutral-point voltage balancing strategies for the derived TANPC multilevel converter family are also …

Minimum Voltage Operation of Cascaded H-Bridge StatComs Using Discontinuous Modulation

Authors

Qingxiang Liu,Ezequiel Rodriguez,Yu Zeng,Glen G Farivar,Christopher D Townsend,Josep Pou

Journal

IEEE Transactions on Power Electronics

Published Date

2024/2/6

Operating cascaded H-bridge (CHB) static compensators (StatCom) at low dc capacitor voltages reduces voltage stress on submodule capacitors and switching semiconductors, resulting in enhanced system reliability and reduced power loss. Understanding the minimum allowable value for peak capacitor voltage is crucial for the optimal capacitor voltage operation of CHB StatComs. This letter proposes an offset-free discontinuous pulsewidth modulation (DPWM) strategy for CHB StatComs. Unlike conventional DPWM strategies, the proposed offset-free DPWM allows the CHB StatCom to operate with minimum peak capacitor voltage. This results in reduced switching loss and lower voltage stress across submodule components. In contrast to existing third-harmonic zero-sequence voltage strategies, the proposed offset-free DPWM does not require accurate capacitance knowledge and is effective in unbalanced …

Deep Reinforcement Learning-Enabled Distributed Uniform Control for a DC Solid State Transformer in DC Microgrid

Authors

Yu Zeng,Josep Pou,Changjiang Sun,Xinze Li,Gaowen Liang,Yang Xia,Suvajit Mukherjee,Amit Kumar Gupta

Journal

IEEE Transactions on Industrial Electronics

Published Date

2023/7/26

This article proposes a distributed uniform control approach for a dc solid state transformer (DCSST) that feeds constant power loads. The proposed approach utilizes a multiagent deep reinforcement learning (MADRL) technique to coordinate multiple control objectives. During the offline training stage, each DRL agent supervises a submodule (SM) of the DCSST, and outputs real-time actions based on the received states. Optimal phase-shift ratio combinations are learned using triple phase-shift modulation, and soft actor-critic (SAC) agents optimize the neural network parameters to enhance controller performance. The well-trained agents act as fast surrogate models that provide online control decisions for the DCSST, adapting to variant environmental conditions using only local SM information. The proposed distributed configuration improves redundancy and modularity, facilitating hot-swap experiments …

Low-Capacitance Static Compensators: Prospects and Challenges

Authors

Ong Jing Xian,Qingxiang Liu,Ezequiel Rodriguez,Glen G Farivar,Josep Pou

Published Date

2023/10/16

Cascaded H-bridge (CHB) static compensator (Stat-Com) enhances stability of the electricity power grid, which is becoming ever increasingly vulnerable as a consequence of replacing fossil fuel-based synchronous generators by intermitten renewable sources. A CHB StatCom needs large dc capacitors in the submodules to operate, which is a major drawback that hinders a widespread use of this technology. In order to overcome this drawback, the low-capacitance StatCom (LC-StatCom) technology was developed. Other than reducing the capacitors size, improvement in power quality and reduced losses were listed as further advantages of the LC-StatCom. On the other hand, control challenges and reduced stable operating range are the main challenges of this technology. This study aims to provide a better understanding of the prospects and challenges of the LC-StatCom technology as compared to the …

High Voltage Selective Global Flexible Power Point Tracking for Photovoltaic Systems

Authors

Anusha Kumaresan,Hossein Dehghani Tafti,Glen G Farivar,Neha Beniwal,Naga Brahmendra Yadav Gorla,Josep Pou,Kai Strunz

Published Date

2023/10/29

To provide frequency support in grid-connected photovoltaic (PV) systems with low inertia, flexible power point tracking (FPPT) control algorithms have been developed in the literature. To achieve this, a power reference obtained from the energy management system is used to control the PV output power. For PV systems to operate with FPPT, the frequent phenomenon of partial shading of PV arrays must be investigated. Among the multiple operating points possible for a given power reference, the one with a high voltage level should be selected in order to minimize the current stress on the semiconductor devices and to reduce the converter thermal stress. This work proposes an improved secant method to achieve this objective, which converges to a voltage reference that is higher than the global maximum power point voltage. The performance of the proposed high voltage selective global FPPT algorithm is …

Comparison of Three-Clamping-Level and Two-Clamping-Level Discontinuous Modulations in Cascaded H-Bridge Static Compensators

Authors

Qingxiang Liu,Ezequiel Rodriguez,Glen G Farivar,Christopher D Townsend,Josep Pou,Ramon Leyva

Published Date

2023/10/29

This paper formulates a three-clamping-level discontinuous pulsewidth modulation (DPWM) for three-phase cascaded H-bridge static compensators with star configuration. Analytical expressions of capacitor voltage and zero-sequence voltage under the three-clamping-level DPWM are provided considering the inherent capacitor voltage oscillations. Based on the derived expressions, the paper analyses: (i) the inductive operation limits, and (ii) the total harmonic distortion (THD) and weighted THD of the output voltages. The results are compared with the continuous modulation and the conventional two-clamping-level DPWM, showing their different performances.

Data-Driven Modeling of Zero Voltage Switching of Non-Resonant DAB Converters under TPS Modulation

Authors

Xinze Li,Fanfan Lin,Josep Pou,Suvajit Mukherjee,Jiaxin Dong

Published Date

2023/3/19

DAB converters under triple phase shift (TPS) modulation can broaden the zero voltage switching (ZVS) range to improve efficiency and noise robustness. Conventionally, the piecewise approach and harmonic approach are two commonly used approaches to build analytical models for ZVS conditions under this modulation strategy. However, both two approaches fail to achieve good modeling accuracy as well as low computational cost simultaneously due to heavy human dependence. To solve this problem, this digest proposes a data-driven modeling approach for ZVS analysis (DM-ZVS) for non-resonant DAB converters under the TPS modulation strategy. The data-driven modeling process is conducted with the random forest algorithm automatically using ZVS performance data from simulation tools, greatly mitigating human dependence to improve accuracy and computational efficiency. With the trained data …

Flexible Power Point Tracking Aided Power Ramp Rate Control for Photovoltaic Systems with Small Energy Storage Capacity

Authors

Hein Wai Yan,Gaowen Liang,Neha Beniwal,Ezequiel Rodriguez,Glen G Farivar,Josep Pou

Journal

IEEE Transactions on Power Electronics

Published Date

2023/11/16

Solar photovoltaic (PV) power generation inherently fluctuates due to erratic weather conditions. Although an energy storage system (ESS) can effectively mitigate these fluctuations, conventional methods require a large ESS capacity to control both increasing and decreasing rates of PV power change. This article explores an opportunity to reduce the required ESS capacity in PV power smoothing applications by delegating the power smoothing during positive irradiance transients to a flexible power point tracking algorithm. Therefore, the ESS only needs to regulate the power ramp rate during negative irradiance transients and it no longer requires the reserved capacity for positive transients. After discharging the ESS, the proposed control fully restores it without violating the allowed ramp rate. The efficacy of the proposed power ramp rate control under rapid irradiance transients is demonstrated experimentally using …

Review of fault diagnosis and fault-tolerant control methods of the modular multilevel converter under submodule failure

Authors

Qian Xiao,Yu Jin,Hongjie Jia,Yi Tang,Allan Fagner Cupertino,Yunfei Mu,Remus Teodorescu,Frede Blaabjerg,Josep Pou

Journal

IEEE Transactions on Power Electronics

Published Date

2023/6/6

Modular multilevel converters (MMCs) have attracted extensive research interests in various ac and dc conversion applications due to their modular structure and excellent harmonic performance. However, the large number of power switches increases the potential risk of submodule (SM) failure, which greatly challenges the safe and reliable operation of the MMC. This article presents a detailed review of fault diagnosis and fault-tolerant control methods of the MMC under SM failures. On this basis, comprehensive comparisons are conducted among different fault diagnosis methods, and verification results are provided to analyze the advantages and disadvantages of the popular fault-tolerant control methods. Finally, the review is concluded, and future trends and research opportunities are discussed.

Data-Driven Modeling with Experimental Augmentation for the Modulation Strategy of the Dual-Active-Bridge Converter

Authors

Xinze Li,Josep Pou,Jiaxin Dong,Fanfan Lin,Changyun Wen,Suvajit Mukherjee,Xin Zhang

Journal

IEEE Transactions on Industrial Electronics

Published Date

2023/4/11

For the performance modeling of power converters, the mainstream approaches are essentially knowledge-based, suffering from heavy manpower burden and low modeling accuracy. Recent emerging data-driven techniques greatly relieve human reliance by automatic modeling from simulation data. However, model discrepancy may occur due to unmodeled parasitics, deficient thermal and magnetic models, unpredictable ambient conditions, etc. These inaccurate data-driven models based on pure simulation cannot represent the practical performance in physical world, hindering their applications in power converter modeling. To alleviate model discrepancy and improve accuracy in practice, this article proposes a novel data-driven modeling with experimental augmentation (D 2 EA), leveraging both simulation data and experimental data. In D 2 EA, simulation data aims to establish basic functional landscape …

Predictive Discontinuous Modulation Strategy with Embedded Inter-Phase Cluster Voltage Control for Cascaded H-Bridge StatComs

Authors

Qingxiang Liu,Ezequiel Rodriguez,Glen G Farivar,Christopher D Townsend,Ramon Leyva,Josep Pou,Jose Rodriguez

Journal

IEEE Transactions on Power Electronics

Published Date

2023/7/24

The discontinuous pulsewidth modulation (DPWM) in cascaded H-bridge (CHB) static compensators (StatComs) is achieved via adding a common mode voltage to the converter voltage references. Hence, in discontinuously operated CHB StatComs, the common mode voltage has two functions, namely, interphase cluster voltage control and clamping a converter voltage. These two functions are conventionally achieved by two independently designed control stages and interferences between them can cause the loss of cluster voltage control during unbalanced grid conditions, since the fundamental frequency common mode voltage for discontinuous operation is significant. To solve this control issue, this article proposes a DPWM strategy with embedded interphase cluster voltage control using a finite control set model predictive control approach. The proposed predictive DPWM outperforms the conventional …

Comparative Analysis of Power Ramp Rate Control Strategies for Photovoltaic Systems

Authors

Hein Wai Yan,Gaowen Liang,Ezequiel Rodriguez,Neha Beniwal,Glen G Farivar,Josep Pou

Published Date

2023/10/16

Intermittent changes in irradiance caused by passing clouds inevitably lead to fluctuations in photovoltaic (PV) power generation. To ensure the stability of a power grid with integrated solar PV generation, a battery energy storage system (BESS) is an intrinsic solution to effectively process the PV power before transmitting it into the grid. Alternatively, a PV software-based ramp rate (RR) control can be applied to mitigate the PV power fluctuations without any BESS, which is known to be cost-effective. The contribution of this paper is to compare various BESS-based and cost-effective software-based RR control strategies operating with real-time measured information, and analyze their effectiveness in regulating the PV power fluctuations. Furthermore, this paper studies the BESS utilization behavior among hardware-based control strategies, and also provides insights into which strategy is more appropriate for …

Medium-Voltage Electric Spring Based on Modular Multilevel Cascaded Converter with Multiple-Outputs

Authors

Hin Sang Lam,Gaowen Liang,Huawei Yuan,Josep Pou,Shu Yuen Ron Hui

Published Date

2023/10/29

The latest medium-voltage electric spring (MV-ES) incorporated into a solid-state transformer provides a possible solution for future electric vehicle charging infrastructure in multistorey car parks and can enhance the stability of the power system in the meantime. The first generation of MV-ES provides only one output port to feed all the loads, lacking flexibility and compromising user experience. This paper proposes a multiple-output MV-ES based on a modular multilevel cascade converter (MMCC) and dual active bridges. The design of multiple outputs enables an extra degree of freedom for separating critical and non-critical loads and is suitable for applications that demand multiple voltage level outputs. The controller design is discussed including the balance of capacitor voltages and the ES functions. The proposed system is verified with microgrid simulation in MATLAB.

Hybrid Duty Ratio Phase-Shift Modulation for a Si+ SiC Neutral-Point-Clamped Dual-Active-Bridge Converter

Authors

Jiaxin Dong,Josep Pou,Xinze Li,Suvajit Mukherjee,Amit K Gupta,Yu Zeng

Journal

IEEE Access

Published Date

2023/11/14

The neutral-point-clamped (NPC) dual-active-bridge (DAB) converter with hybrid semiconductors (Si and SiC devices) is a promising topology for high-power energy storage systems. The triple-phase-shift (TPS) modulation can achieve high efficiency with zero-voltage switching (ZVS) by adjusting three phase shift angles. However, when applied to hybrid DAB topologies, switching and conduction losses are too high. In this paper, a hybrid modulation method using duty ratio and phase-shift is proposed to improve the efficiency of the hybrid NPC DAB converter. The Si and SiC devices on the primary NPC bridges work under different duty ratios with staggered switching instants so that the Si devices do not suffer from the high turn-off current, and the SiC devices benefit from less conduction time. The neutral current path is used to take over the negative current which flows through SiC body diodes under TPS …

Modulation Methods for Balancing the Capacitor Voltages of n-Level Diode-Clamped Converters

Authors

Huawei Yuan,Hin Sang Lam,Neha Beniwal,Josep Pou,Shu-Yuen Ron Hui

Journal

IEEE Transactions on Industrial Electronics

Published Date

2023/1/31

Diode-clamped converters (DCCs) suffer from the inherent capacitor voltage imbalance problem. Most software-based voltage-balancing methods fall into the space vector modulation category and the carrier-based pulsewidth modulation category. Despite their effectiveness for the three-level DCCs, it is not easy to extend them to a general n -level topology. In this article, a new modulation method of a category called good-switching (GS) PWM is proposed for balancing the capacitor voltages. The proposed method requires no parameter-tuning effort and is extremely simple to design even for the n -level topology regardless of the number of phases. It is also potentially applicable to other multilevel converters. The principle, the implementation, and the stability analysis of GS-PWM are elaborated for a generic n -level DCC. A modified GS-PWM scheme and an on–off control scheme are proposed to reduce the …

See List of Professors in Josep Pou University(Nanyang Technological University)

Josep Pou FAQs

What is Josep Pou's h-index at Nanyang Technological University?

The h-index of Josep Pou has been 53 since 2020 and 67 in total.

What are Josep Pou's top articles?

The articles with the titles of

Constant Current Precharging Algorithm for Solid State Power Controllers

Comparison of adaptive P/ω droop strategies for intermittent energy sources in emergency islanded operation

Virtual Arm Impedance Emulation and Stability Improvement in Modular Multilevel Converters

Asymmetrical-Bidirectional Input-Series–Output-Parallel Modular DC–DC Converter in DC Distribution Grids With Renewables

Reactive Power Distribution in the Cascaded H-Bridge Converter With Unbalanced Submodule Active Power for Capacitance Reduction

A Generalized Derivation Method of Tree-Type Active Neutral-Point-Clamped Multilevel Topologies

Minimum Voltage Operation of Cascaded H-Bridge StatComs Using Discontinuous Modulation

Deep Reinforcement Learning-Enabled Distributed Uniform Control for a DC Solid State Transformer in DC Microgrid

...

are the top articles of Josep Pou at Nanyang Technological University.

What are Josep Pou's research interests?

The research interests of Josep Pou are: Power Electronics, Multilevel Converters, Renewable Energy, Energy Storage

What is Josep Pou's total number of citations?

Josep Pou has 21,415 citations in total.

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