Ching-Ming Lai | National Taipei University of Technology (original) (raw)
Papers by Ching-Ming Lai
2015 IEEE 2nd International Future Energy Electronics Conference (IFEEC)
The objective of this paper is to present a novel bidirectional dc/dc converter topology with a h... more The objective of this paper is to present a novel bidirectional dc/dc converter topology with a high voltage conversion ratio for electric vehicle (EV) batteries connected to dc-microgrid system. In this study, an unregulated level converter (ULC) cascaded with a two-phase interleaved buck-boost charge-pump converter is introduced to achieve a high conversion ratio with very simple control circuits. In discharge mode, the topology acts as a two-stage voltage-doubler boost converter to achieve high step-up conversion ratio (48V to 400V). In charge mode, the converter acts as two cascaded voltage-divider buck converters to achieve high voltage step-down conversion ratio (400V to 48V). The steady-state analysis and numerical simulation are made to verify the performance of the proposed newly constructed bidirectional converter.
Energies
Electricity demand has surged over the last several years and will persist in the future. Increas... more Electricity demand has surged over the last several years and will persist in the future. Increased transmission loads cause transmission lines to operate much closer to their security limits, leading to thermal and mechanical stress and thus affecting the transmission reliability and thermal aging. Accordingly, monitoring the conductor temperature over time is critical to identifying power transmission networks that may need extra attention and perhaps maintenance. This paper presents a fuzzy thermal aging model for transmission lines equipped with a fuzzy dynamic thermal rating system based on the IEEE 738 standard. In this framework, the ampacity of the transmission line was calculated. The conductor temperature was computed with the back-calculation method by considering the fully loaded transmission line. The estimated conductor temperature was employed to determine the corresponding conductor fuzzy loss of tensile strength, i.e., the fuzzy annealing degree of the conductor bas...
Third International Conference on Advances in Applied Science and Environmental Technology - ASET 2015, 2015
Particle swarm optimization (PSO) is a well-known and popular swarm intelligence algorithm. The i... more Particle swarm optimization (PSO) is a well-known and popular swarm intelligence algorithm. The inertia weight of a PSO plays the crucial role in the ability of exploration and exploitation. Many strategies for adapting the inertia weight of PSO have been proposed. In this study, we use two inertia weights to improve the global and local search of PSO. Nine benchmark functions with 10 dimensions for unimodal functions, multimodal functions with many local optima, and multimodal functions with a few local optima is used as the test functions. We compare two inertia weight PSOs with the proposed method. The results show the proposed method is useful for improve the search ability of PSO.
2016 IEEE Vehicle Power and Propulsion Conference (VPPC), 2016
This paper studies a battery-powered high step-up front-end converter for automotive audio amplif... more This paper studies a battery-powered high step-up front-end converter for automotive audio amplifier. The proposed converter uses an interleaved structure with one-phase utilizing a conventional boost converter and the second-phase uses its inverted version. By this technique a high step-up voltage gain can be obtained as compared to the conventional two-phase interleaved boost converter. Operating principles and analyzes of the proposed converter topology is derived. Simulation and experimental results of a 120W circuit was made by a battery input voltage of 12V, while the reasonable duty cycle was sized to achieve an output voltage of 60V, corresponding to a static voltage gain Gv=5. The measured maximum conversion efficiency of the converter is 98.6%, and the efficiency at full load is 95.2%.
IEEE Access, 2021
This paper proposes a novel approach in the offline Software-in-the-Loop (SIL) simulation techniq... more This paper proposes a novel approach in the offline Software-in-the-Loop (SIL) simulation technique to speed up the firmware development cycle of power electronics and enhance the firmware maintenance of commercial products. In the conventional SIL simulation process, Model-in-the-Loop (MIL) is always performed prior to the execution of SIL because it allows users to automatically generate C code for testing in the subsequent SIL. Furthermore, the target device can be programmed with the compiled files only if the simulation tools support specific models of control chips. In light of this, the goal to use SIL to validate firmware in early power electronics product development becomes more complex and limited due to the limited selection of simulation tools. In this paper, non-preemptive scheduling (NPS) and common firmware architecture (CFA) are explored to illustrate the integration of the application layer for implementing the proposed offline SIL. Users can directly use circuit simulation software that supports Dynamic-Link Library (DLL) to simultaneously develop source codes and verify the offline SIL process of the product. To further illustrate the practical application of the power electronics product in the microcontroller (MCU) mock model and the power stage circuit model, a single 300W power module composed of three single-phase quasi-resonant (QR) flyback current source converters connected in parallel and cascaded with an H-bridge unfolder is used as an example to execute offline SIL in the SIMULINK. Finally, a system-level experiment was conducted to validate the firmware of 16 power modules assembled in a 4.8 kW fuel cell (FC) grid-tie inverter system, which was modulated through the power management unit (PMU) and the monitoring graphical user interface (GUI). INDEX TERMS Offline software-in-the-loop, non-preemptive scheduling (NPS), common firmware architecture (CFA), modular single-phase flyback current source inverter system.
Sustainability, 2021
The objective of this paper is to study a 22 kW high-power wireless power transfer (WPT) system f... more The objective of this paper is to study a 22 kW high-power wireless power transfer (WPT) system for battery charging in electric vehicles (EVs). The proposed WPT system consists of a three-phase half-bridge LC–LC (i.e., primary LC/secondary LC) resonant power converter and a three-phase sandwich wound coil set (transmitter, Tx; receiver, Rx). To transfer power effectively with a 250 mm air gap, the WPT system uses three-phase, sandwich-wound Tx/Rx coils to minimize the magnetic flux leakage effect and increase the power transfer efficiency (PTE). Furthermore, the relationship of the coupling coefficient between the Tx/Rx coils is complicated, as the coupling coefficient is not only dominated by the coupling strength of the primary and secondary sides but also relates to the primary or secondary three-phase magnetic coupling effects. In order to analyze the proposed three-phase WPT system, a detailed equivalent circuit model is derived for a better understanding. To give a design ref...
2017 IEEE 8th International Conference on Awareness Science and Technology (iCAST), 2017
As the energy crisis and environmental pollution problems become increasingly serious, hybrid ele... more As the energy crisis and environmental pollution problems become increasingly serious, hybrid electric vehicles (HEVs) have been seen as the world's more fuel-efficient and cleaner vehicles to provide one of the solutions. In this study, we designed the appropriate control strategy parameters use memetic algorithm (MA) with two small population sizes 5 and 10 and iterations 1000 to make the HEV not only reduce the toxic emissions, but also keep the road driving vehicle performance while reducing fuel consumption (FC). In this study, the software ADVISOR was used as a simulation tool and the driving cycle UDDS was used to evaluate FC, emissions and vehicle dynamic performance. Compared with the preset parallel HEV defined in ADVISOR, the results show that MA is a powerful tool for improving the control strategy parameters of the parallel HEV to improve FC and emissions without sacrificing vehicle performance. The method helps to mitigate the energy crisis and environmental pollution problems.
IEEE Journal of Emerging and Selected Topics in Industrial Electronics, 2021
This paper presents a resonant frequency tuning (RFT) Delta-Sigma (-) signal-transformed pulse de... more This paper presents a resonant frequency tuning (RFT) Delta-Sigma (-) signal-transformed pulse density modulation (PDM) class-D converter for inductive power transfer (IPT) applications. The proposed power controller provides a load-adaptable pulse modulation by tracking a zero phase angle(ZPA) and peak-power frequency, i.e. resonant frequency in the primary-side high frequency inverter. The switching frequency is regulated in accordance with the variations of the load and coupling co-efficient between the transmitting(Tx) and receiving(Rx) coils. The output power is controlled by the RFT - PDM which is effective for reducing a low frequency oscillation (subharmonics), thereby the high efficiency power transmission can attain. The essential performances of the proposed IPT power controller are demonstrated in experiment of a 400W-500kHz of prototype, whereby the feasibility is clarified from a practical point of view.
Energies, 2020
This paper presents a new method for reducing the total harmonic distortion (THD) of photovoltaic... more This paper presents a new method for reducing the total harmonic distortion (THD) of photovoltaic (PV) systems by using an adaptive filter based on a predictive model. Instead of reducing the produced THD at each stage of the PV system, a one-step process is implemented at the end stage. The connection topology of the adaptive filter is similar to normal active and passive filters. The main difference is its ability to adjust the filtering coefficients while others cannot. The proposed method is applied to a single-phase standalone PV system by adopting least mean square (LMS), normalized LMS (NLMS) and leaky LMS algorithms to verify the validity of the proposed method. Various values of filter length and step size are evaluated, and results indicate that the proposed method can reduce THD in the current signal of the PV system significantly by using all of the mentioned algorithms. Different step sizes and filter lengths directly influence the effectiveness of the THD reduction, wi...
Energies, 2018
Power systems has been subjected to significant upgrades in terms of structure and capacity. Reli... more Power systems has been subjected to significant upgrades in terms of structure and capacity. Reliability evaluation of composite power systems has surfaced as an essential step in operation and planning stages of the modern power system. It is an effective tool to investigate the ability of power systems to supply customers with reliable power service. The purpose of this review is to enhance the knowledge of reliability studies conducted on composite power systems by providing a critical and systematic review. This work investigates peer-reviewed articles published between 2007 and 2017 in three reliable databases. The findings reveal that the reliability of composite power systems has received considerable attention over the last few years. Secondly, investigation studies demonstrated a crucial role in verifying the impact of adopting new technologies. Third, studies on this topic have been intensively conducted in Asia, which highlights the promising sectors in these regions. How...
IEEE Access, 2019
This paper presents a risk-based management framework for transmission lines equipped with a dyna... more This paper presents a risk-based management framework for transmission lines equipped with a dynamic thermal rating system. In this framework, future wind speed values required for calculating conductor temperature are forecasted using the auto-regressive moving-average model. The dynamic thermal model used in this paper is based on the IEEE 738 standard. The forecasted conductor temperature is used to determine the associated conductor loss of tensile strength, i.e., the annealing degree of the conductor, on the basis of the Harvey model. A cost profile is also provided for tensile strength lost. Simultaneously, temperature and conductor age are used to predict the failure probability of the conductor using the Arrhenius-Weibull model. Finally, the product of the economics of conductor annealing and conductor failure probability provides the risk value, which can be compared with the admissible risk. The results show that risk can be mitigated by reducing either conductor temperature or the applied duration of the conductor. Moreover, a desirable forecast of wind speed values also poses less risk and vice versa. The sensitivity analyses show that the considerations taken during the formulation of the framework are reasonable and they only affect the numerical results, thereby indicating that the proposed framework is robust against various operating conditions of the parameters considered in the framework.
AIMS Energy, 2017
The control strategy is a major unit in hybrid electric vehicles (HEVs). In order to provide suit... more The control strategy is a major unit in hybrid electric vehicles (HEVs). In order to provide suitable control parameters for reducing fuel consumptions and engine emissions while maintaining vehicle performance requirements, the genetic algorithm (GA) with small population size is applied to search for feasible control parameters in parallel HEVs. The electric assist control strategy (EACS) is used as the fundamental control strategy of parallel HEVs. The dynamic performance requirements stipulated in the Partnership for a New Generation of Vehicles (PNGV) is considered to maintain the vehicle performance. The known ADvanced VehIcle SimulatOR (ADVISOR) is used to simulate a specific parallel HEV with urban dynamometer driving schedule (UDDS). Five population sets with size 5, 10, 15, 20, and 25 are used in the GA. The experimental results show that the GA with population size of 25 is the best for selecting feasible control parameters in parallel HEVs.
IEEE Access, 2019
The dynamic thermal rating (DTR) system is one of most widely used state-of-the-art of smart grid... more The dynamic thermal rating (DTR) system is one of most widely used state-of-the-art of smart grids owing to its proven ability to improve the existing line ratings at a fraction of the cost of most extant methods without infringing line safety requirements. However, the successful implementation of this system depends on the reliability of communication networks, especially wireless communication systems, in transmitting line rating information back to the utility company so that an appropriate line flow control can be executed. Therefore, the efficient, continuous, and secure operations of smart grids are equally affected by the reliability of the DTR and wireless communication systems. Despite this evidence, the reliability impacts of these systems on power grids are yet to be examined in a single framework. In this paper, a new model for investigating the reliability impacts of the DTR system on power grids considering the wireless communication network is proposed. The inability of the DTR system to perform, either due to its unavailability or communication failure, is taken as a function of line ratings that affect the transmission capacity and reliability of power grids. When the DTR system service is unavailable, the line rating is either reverted to the static thermal rating or estimated via the multi-linear regression (MLR) model based on information from neighboring regions. The comparison of these two models on the IEEE 24-bus reliability test system reveals that the MLR model is more beneficial in mitigating DTR and communication systems failures. This paper also explores various communication system failure scenarios and the reliability impacts of redundancy designs. The findings reveal that the communication system with moderate reliability levels yield the most benefits when the redundancy number increases from 1 to 4. Overall, the communication system significantly affects the availability of the DTR system. INDEX TERMS Dynamic thermal rating systems, power system, reliability, wireless communication network, smart grid.
Energy and Power Engineering, 2014
This paper proposes a single-stage inverter system with maximum power point tracking control (MPP... more This paper proposes a single-stage inverter system with maximum power point tracking control (MPPT) applicable in low-power photovoltaic (PV) energy conversion systems. The proposed system is successfully implemented using a single digital signal processor (DSP) TMS320F2808. The proposed single-stage inverter system has the following features: 1) the ability to harvest the maximum PV power using two simple and effective current sampling methods; 2) flexible topology based on the positioning of DC link capacitor on the outside of the inverter bridge circuits; 3) reduced volume and higher efficiency than the conventional two-stage inverters, and 4) MPPT accuracy of 99.3% with overall efficiency of 90% under the full-load condition.
IEEE Transactions on Vehicular Technology, 2018
This study develops a newly designed, patented, bidirectional dc/dc converter (BDC) that interfac... more This study develops a newly designed, patented, bidirectional dc/dc converter (BDC) that interfaces a main energy storage (ES1), an auxiliary energy storage (ES2), and dc-bus of different voltage levels, for application in hybrid electric vehicle systems. The proposed converter can operate in a step-up mode (i.e., low-voltage dual-source-powering mode) and a step-down (i.e., high-voltage dc-link energy-regenerating mode), both with bidirectional power flow control. In addition, the model can independently control power flow between any two low-voltage sources (i.e., low-voltage dual-source buck/boost mode). Herein, the circuit configuration, operation, steady-state analysis, and closed-loop control of the proposed BDC are discussed according to its three modes of power transfer. Moreover, the simulation and experimental results for a 1 kW prototype system are provided to validate the proposed converter. Index Terms-Bidirectional dc/dc converter (BDC), dual battery storage, hybrid electric vehicle. I. INTRODUCTION lobal climate change and energy supply is declining have stimulated changes in vehicular technology. Advanced technologies are currently being researched for application in future vehicles. Among such applications, fuel-cell hybrid electric vehicles (FCV/HEV) are efficient and promising candidates. In the past, Ehsani et al. studied the vehicles' dynamics to look for an optimal torque-speed profile of the electric propulsion system [1]. Emadi et al. discussed the
2020 International Automatic Control Conference (CACS), 2020
In this paper, a novel mathematical model based on RC circuit for investigating the gel battery i... more In this paper, a novel mathematical model based on RC circuit for investigating the gel battery is presented. The proposed mathematical model consists of a polynomial term and an exponential term which can present the discharging behavior of a battery. The polynomial term represents the stable discharging behavior and the exponential term represents the unstable discharging behavior. The proposed model proved that the aging of a battery increases with cycle numbers and reflects the variation in the parameters of the model in state of charge (SoC) of a battery. In addition, a simpler algorithm that estimates part of the discharging characteristics to predict SoC of a battery also presented in this work. The algorithm has shorter computing time, higher efficiency and greater convenience. Through the experiments that practical operations, maximum absolute percentage error of SoC for the relationship between measurement and fitting data is 1.83%. The results mean that the proposed model has been verified, demonstrating its effectiveness and accuracy.
2017 IEEE 8th International Conference on Awareness Science and Technology (iCAST), 2017
In this work we examine how the updates addressing Meltdown and Spectre vulnerabilities impact th... more In this work we examine how the updates addressing Meltdown and Spectre vulnerabilities impact the performance of HPC applications. To study this we use the application kernel module of XDMoD to test the performance before and after the application of the vulnerability patches. We tested the performance difference for multiple application and benchmarks including: NWChem, NAMD, HPCC, IOR, MDTest and IMB. The results show that although some specific functions can have perfomance decreased by as much as 74%, the majority of individual metrics indicates little to no decrease in performance. The real-world applications show a 2-3% decrease in performance for single node jobs and a 5-11% decrease for parallel multi node jobs.
2016 IEEE Transportation Electrification Conference and Expo, Asia-Pacific (ITEC Asia-Pacific), 2016
A newly-designed multiport bidirectional power converter is studied to interface battery, superca... more A newly-designed multiport bidirectional power converter is studied to interface battery, supercapacitor and dc-bus of different voltage levels for hybrid electric/fuel-cell vehicle (HEV/FCV) system. The converter can be used to operate in both the step-down and step-up modes with bidirectional power flow control. The operating modes of proposed topology can be classified into low-voltage dual sources powering boost mode and high-voltage dc-link energy-regenerating buck mode. Also, It is possible to independently control power flow between any two low-voltage sources, i.e. low-voltage dual sources buck/boost mode. The operation, analysis, and design of the converter are proposed with different modes of power transfer. Experimental results for a 1-kW system are provided, validating the theoretical analysis.
2015 IEEE 2nd International Future Energy Electronics Conference (IFEEC), 2015
In this paper, a simple modular passive ripple mirror circuit (PRMC) is adopted for eliminating t... more In this paper, a simple modular passive ripple mirror circuit (PRMC) is adopted for eliminating the inherent high frequency current ripple of pulse-width modulated (PWM) DC-DC converters. The PRMC doesn't require any additional active switches, driver circuits or any extra control; the cost can be saved easily. Only the reflected high frequency ripples are automatically induced and processed for proper cancellation with the original ripples. It turns out that not only the output power quality can be enhanced but also the inductance of the main power conversion circuit can be reduced greatly. In this paper, both the circuit structure and operation principle of the PRMC are described. Furthermore, the PRMC technique is then integrated into a family of PWM DC-DC converters, such as buck, boost, Cuk, Zeta, and SEPIC converters. Finally, as the demonstration, experimental results of the Cuk PWM converter integrated with PRMC are provided to verify the feasibility of the principle.
A single-stage ac/dc LLCresonant converter is Experimental results obtained fromanac1lOVline inpu... more A single-stage ac/dc LLCresonant converter is Experimental results obtained fromanac1lOVline input, proposed todrawasinusoidal line current, forachievingand28V/3Aoutput laboratory prototype, arepresented. powerfactor correction (PFC).Theproposed ac/dc Finally, theproposed single-stage LLC-SRCconverter converter composes ofa boost-PFC semi-stage anda successfully meets theIEC1000-3-2 Class-D requirements, LLC-SRCsemi-stage. Theboost-PFC semi-stage, workingandnearly a unity powerfactor. Also,theconversion indiscontinuous conduction mode(DCM)functions asa efficiency canbeachieved upto86%,undera rated powerfactor corrector, andtheLLC-SRCsemi-stage condition. Theseexperimental results areveryattractive as operates abovetheresonance toachieve zero-voltage theory predicts. switching (ZVS)operation. Theproposed converter hasthe feature ofvariable-frequency control, whichprovides a dioderectifier tofeedtheboost-PFC semi-stage. The half-bridge switch pairoperates atasymmetrical ratio D Conven...
2015 IEEE 2nd International Future Energy Electronics Conference (IFEEC)
The objective of this paper is to present a novel bidirectional dc/dc converter topology with a h... more The objective of this paper is to present a novel bidirectional dc/dc converter topology with a high voltage conversion ratio for electric vehicle (EV) batteries connected to dc-microgrid system. In this study, an unregulated level converter (ULC) cascaded with a two-phase interleaved buck-boost charge-pump converter is introduced to achieve a high conversion ratio with very simple control circuits. In discharge mode, the topology acts as a two-stage voltage-doubler boost converter to achieve high step-up conversion ratio (48V to 400V). In charge mode, the converter acts as two cascaded voltage-divider buck converters to achieve high voltage step-down conversion ratio (400V to 48V). The steady-state analysis and numerical simulation are made to verify the performance of the proposed newly constructed bidirectional converter.
Energies
Electricity demand has surged over the last several years and will persist in the future. Increas... more Electricity demand has surged over the last several years and will persist in the future. Increased transmission loads cause transmission lines to operate much closer to their security limits, leading to thermal and mechanical stress and thus affecting the transmission reliability and thermal aging. Accordingly, monitoring the conductor temperature over time is critical to identifying power transmission networks that may need extra attention and perhaps maintenance. This paper presents a fuzzy thermal aging model for transmission lines equipped with a fuzzy dynamic thermal rating system based on the IEEE 738 standard. In this framework, the ampacity of the transmission line was calculated. The conductor temperature was computed with the back-calculation method by considering the fully loaded transmission line. The estimated conductor temperature was employed to determine the corresponding conductor fuzzy loss of tensile strength, i.e., the fuzzy annealing degree of the conductor bas...
Third International Conference on Advances in Applied Science and Environmental Technology - ASET 2015, 2015
Particle swarm optimization (PSO) is a well-known and popular swarm intelligence algorithm. The i... more Particle swarm optimization (PSO) is a well-known and popular swarm intelligence algorithm. The inertia weight of a PSO plays the crucial role in the ability of exploration and exploitation. Many strategies for adapting the inertia weight of PSO have been proposed. In this study, we use two inertia weights to improve the global and local search of PSO. Nine benchmark functions with 10 dimensions for unimodal functions, multimodal functions with many local optima, and multimodal functions with a few local optima is used as the test functions. We compare two inertia weight PSOs with the proposed method. The results show the proposed method is useful for improve the search ability of PSO.
2016 IEEE Vehicle Power and Propulsion Conference (VPPC), 2016
This paper studies a battery-powered high step-up front-end converter for automotive audio amplif... more This paper studies a battery-powered high step-up front-end converter for automotive audio amplifier. The proposed converter uses an interleaved structure with one-phase utilizing a conventional boost converter and the second-phase uses its inverted version. By this technique a high step-up voltage gain can be obtained as compared to the conventional two-phase interleaved boost converter. Operating principles and analyzes of the proposed converter topology is derived. Simulation and experimental results of a 120W circuit was made by a battery input voltage of 12V, while the reasonable duty cycle was sized to achieve an output voltage of 60V, corresponding to a static voltage gain Gv=5. The measured maximum conversion efficiency of the converter is 98.6%, and the efficiency at full load is 95.2%.
IEEE Access, 2021
This paper proposes a novel approach in the offline Software-in-the-Loop (SIL) simulation techniq... more This paper proposes a novel approach in the offline Software-in-the-Loop (SIL) simulation technique to speed up the firmware development cycle of power electronics and enhance the firmware maintenance of commercial products. In the conventional SIL simulation process, Model-in-the-Loop (MIL) is always performed prior to the execution of SIL because it allows users to automatically generate C code for testing in the subsequent SIL. Furthermore, the target device can be programmed with the compiled files only if the simulation tools support specific models of control chips. In light of this, the goal to use SIL to validate firmware in early power electronics product development becomes more complex and limited due to the limited selection of simulation tools. In this paper, non-preemptive scheduling (NPS) and common firmware architecture (CFA) are explored to illustrate the integration of the application layer for implementing the proposed offline SIL. Users can directly use circuit simulation software that supports Dynamic-Link Library (DLL) to simultaneously develop source codes and verify the offline SIL process of the product. To further illustrate the practical application of the power electronics product in the microcontroller (MCU) mock model and the power stage circuit model, a single 300W power module composed of three single-phase quasi-resonant (QR) flyback current source converters connected in parallel and cascaded with an H-bridge unfolder is used as an example to execute offline SIL in the SIMULINK. Finally, a system-level experiment was conducted to validate the firmware of 16 power modules assembled in a 4.8 kW fuel cell (FC) grid-tie inverter system, which was modulated through the power management unit (PMU) and the monitoring graphical user interface (GUI). INDEX TERMS Offline software-in-the-loop, non-preemptive scheduling (NPS), common firmware architecture (CFA), modular single-phase flyback current source inverter system.
Sustainability, 2021
The objective of this paper is to study a 22 kW high-power wireless power transfer (WPT) system f... more The objective of this paper is to study a 22 kW high-power wireless power transfer (WPT) system for battery charging in electric vehicles (EVs). The proposed WPT system consists of a three-phase half-bridge LC–LC (i.e., primary LC/secondary LC) resonant power converter and a three-phase sandwich wound coil set (transmitter, Tx; receiver, Rx). To transfer power effectively with a 250 mm air gap, the WPT system uses three-phase, sandwich-wound Tx/Rx coils to minimize the magnetic flux leakage effect and increase the power transfer efficiency (PTE). Furthermore, the relationship of the coupling coefficient between the Tx/Rx coils is complicated, as the coupling coefficient is not only dominated by the coupling strength of the primary and secondary sides but also relates to the primary or secondary three-phase magnetic coupling effects. In order to analyze the proposed three-phase WPT system, a detailed equivalent circuit model is derived for a better understanding. To give a design ref...
2017 IEEE 8th International Conference on Awareness Science and Technology (iCAST), 2017
As the energy crisis and environmental pollution problems become increasingly serious, hybrid ele... more As the energy crisis and environmental pollution problems become increasingly serious, hybrid electric vehicles (HEVs) have been seen as the world's more fuel-efficient and cleaner vehicles to provide one of the solutions. In this study, we designed the appropriate control strategy parameters use memetic algorithm (MA) with two small population sizes 5 and 10 and iterations 1000 to make the HEV not only reduce the toxic emissions, but also keep the road driving vehicle performance while reducing fuel consumption (FC). In this study, the software ADVISOR was used as a simulation tool and the driving cycle UDDS was used to evaluate FC, emissions and vehicle dynamic performance. Compared with the preset parallel HEV defined in ADVISOR, the results show that MA is a powerful tool for improving the control strategy parameters of the parallel HEV to improve FC and emissions without sacrificing vehicle performance. The method helps to mitigate the energy crisis and environmental pollution problems.
IEEE Journal of Emerging and Selected Topics in Industrial Electronics, 2021
This paper presents a resonant frequency tuning (RFT) Delta-Sigma (-) signal-transformed pulse de... more This paper presents a resonant frequency tuning (RFT) Delta-Sigma (-) signal-transformed pulse density modulation (PDM) class-D converter for inductive power transfer (IPT) applications. The proposed power controller provides a load-adaptable pulse modulation by tracking a zero phase angle(ZPA) and peak-power frequency, i.e. resonant frequency in the primary-side high frequency inverter. The switching frequency is regulated in accordance with the variations of the load and coupling co-efficient between the transmitting(Tx) and receiving(Rx) coils. The output power is controlled by the RFT - PDM which is effective for reducing a low frequency oscillation (subharmonics), thereby the high efficiency power transmission can attain. The essential performances of the proposed IPT power controller are demonstrated in experiment of a 400W-500kHz of prototype, whereby the feasibility is clarified from a practical point of view.
Energies, 2020
This paper presents a new method for reducing the total harmonic distortion (THD) of photovoltaic... more This paper presents a new method for reducing the total harmonic distortion (THD) of photovoltaic (PV) systems by using an adaptive filter based on a predictive model. Instead of reducing the produced THD at each stage of the PV system, a one-step process is implemented at the end stage. The connection topology of the adaptive filter is similar to normal active and passive filters. The main difference is its ability to adjust the filtering coefficients while others cannot. The proposed method is applied to a single-phase standalone PV system by adopting least mean square (LMS), normalized LMS (NLMS) and leaky LMS algorithms to verify the validity of the proposed method. Various values of filter length and step size are evaluated, and results indicate that the proposed method can reduce THD in the current signal of the PV system significantly by using all of the mentioned algorithms. Different step sizes and filter lengths directly influence the effectiveness of the THD reduction, wi...
Energies, 2018
Power systems has been subjected to significant upgrades in terms of structure and capacity. Reli... more Power systems has been subjected to significant upgrades in terms of structure and capacity. Reliability evaluation of composite power systems has surfaced as an essential step in operation and planning stages of the modern power system. It is an effective tool to investigate the ability of power systems to supply customers with reliable power service. The purpose of this review is to enhance the knowledge of reliability studies conducted on composite power systems by providing a critical and systematic review. This work investigates peer-reviewed articles published between 2007 and 2017 in three reliable databases. The findings reveal that the reliability of composite power systems has received considerable attention over the last few years. Secondly, investigation studies demonstrated a crucial role in verifying the impact of adopting new technologies. Third, studies on this topic have been intensively conducted in Asia, which highlights the promising sectors in these regions. How...
IEEE Access, 2019
This paper presents a risk-based management framework for transmission lines equipped with a dyna... more This paper presents a risk-based management framework for transmission lines equipped with a dynamic thermal rating system. In this framework, future wind speed values required for calculating conductor temperature are forecasted using the auto-regressive moving-average model. The dynamic thermal model used in this paper is based on the IEEE 738 standard. The forecasted conductor temperature is used to determine the associated conductor loss of tensile strength, i.e., the annealing degree of the conductor, on the basis of the Harvey model. A cost profile is also provided for tensile strength lost. Simultaneously, temperature and conductor age are used to predict the failure probability of the conductor using the Arrhenius-Weibull model. Finally, the product of the economics of conductor annealing and conductor failure probability provides the risk value, which can be compared with the admissible risk. The results show that risk can be mitigated by reducing either conductor temperature or the applied duration of the conductor. Moreover, a desirable forecast of wind speed values also poses less risk and vice versa. The sensitivity analyses show that the considerations taken during the formulation of the framework are reasonable and they only affect the numerical results, thereby indicating that the proposed framework is robust against various operating conditions of the parameters considered in the framework.
AIMS Energy, 2017
The control strategy is a major unit in hybrid electric vehicles (HEVs). In order to provide suit... more The control strategy is a major unit in hybrid electric vehicles (HEVs). In order to provide suitable control parameters for reducing fuel consumptions and engine emissions while maintaining vehicle performance requirements, the genetic algorithm (GA) with small population size is applied to search for feasible control parameters in parallel HEVs. The electric assist control strategy (EACS) is used as the fundamental control strategy of parallel HEVs. The dynamic performance requirements stipulated in the Partnership for a New Generation of Vehicles (PNGV) is considered to maintain the vehicle performance. The known ADvanced VehIcle SimulatOR (ADVISOR) is used to simulate a specific parallel HEV with urban dynamometer driving schedule (UDDS). Five population sets with size 5, 10, 15, 20, and 25 are used in the GA. The experimental results show that the GA with population size of 25 is the best for selecting feasible control parameters in parallel HEVs.
IEEE Access, 2019
The dynamic thermal rating (DTR) system is one of most widely used state-of-the-art of smart grid... more The dynamic thermal rating (DTR) system is one of most widely used state-of-the-art of smart grids owing to its proven ability to improve the existing line ratings at a fraction of the cost of most extant methods without infringing line safety requirements. However, the successful implementation of this system depends on the reliability of communication networks, especially wireless communication systems, in transmitting line rating information back to the utility company so that an appropriate line flow control can be executed. Therefore, the efficient, continuous, and secure operations of smart grids are equally affected by the reliability of the DTR and wireless communication systems. Despite this evidence, the reliability impacts of these systems on power grids are yet to be examined in a single framework. In this paper, a new model for investigating the reliability impacts of the DTR system on power grids considering the wireless communication network is proposed. The inability of the DTR system to perform, either due to its unavailability or communication failure, is taken as a function of line ratings that affect the transmission capacity and reliability of power grids. When the DTR system service is unavailable, the line rating is either reverted to the static thermal rating or estimated via the multi-linear regression (MLR) model based on information from neighboring regions. The comparison of these two models on the IEEE 24-bus reliability test system reveals that the MLR model is more beneficial in mitigating DTR and communication systems failures. This paper also explores various communication system failure scenarios and the reliability impacts of redundancy designs. The findings reveal that the communication system with moderate reliability levels yield the most benefits when the redundancy number increases from 1 to 4. Overall, the communication system significantly affects the availability of the DTR system. INDEX TERMS Dynamic thermal rating systems, power system, reliability, wireless communication network, smart grid.
Energy and Power Engineering, 2014
This paper proposes a single-stage inverter system with maximum power point tracking control (MPP... more This paper proposes a single-stage inverter system with maximum power point tracking control (MPPT) applicable in low-power photovoltaic (PV) energy conversion systems. The proposed system is successfully implemented using a single digital signal processor (DSP) TMS320F2808. The proposed single-stage inverter system has the following features: 1) the ability to harvest the maximum PV power using two simple and effective current sampling methods; 2) flexible topology based on the positioning of DC link capacitor on the outside of the inverter bridge circuits; 3) reduced volume and higher efficiency than the conventional two-stage inverters, and 4) MPPT accuracy of 99.3% with overall efficiency of 90% under the full-load condition.
IEEE Transactions on Vehicular Technology, 2018
This study develops a newly designed, patented, bidirectional dc/dc converter (BDC) that interfac... more This study develops a newly designed, patented, bidirectional dc/dc converter (BDC) that interfaces a main energy storage (ES1), an auxiliary energy storage (ES2), and dc-bus of different voltage levels, for application in hybrid electric vehicle systems. The proposed converter can operate in a step-up mode (i.e., low-voltage dual-source-powering mode) and a step-down (i.e., high-voltage dc-link energy-regenerating mode), both with bidirectional power flow control. In addition, the model can independently control power flow between any two low-voltage sources (i.e., low-voltage dual-source buck/boost mode). Herein, the circuit configuration, operation, steady-state analysis, and closed-loop control of the proposed BDC are discussed according to its three modes of power transfer. Moreover, the simulation and experimental results for a 1 kW prototype system are provided to validate the proposed converter. Index Terms-Bidirectional dc/dc converter (BDC), dual battery storage, hybrid electric vehicle. I. INTRODUCTION lobal climate change and energy supply is declining have stimulated changes in vehicular technology. Advanced technologies are currently being researched for application in future vehicles. Among such applications, fuel-cell hybrid electric vehicles (FCV/HEV) are efficient and promising candidates. In the past, Ehsani et al. studied the vehicles' dynamics to look for an optimal torque-speed profile of the electric propulsion system [1]. Emadi et al. discussed the
2020 International Automatic Control Conference (CACS), 2020
In this paper, a novel mathematical model based on RC circuit for investigating the gel battery i... more In this paper, a novel mathematical model based on RC circuit for investigating the gel battery is presented. The proposed mathematical model consists of a polynomial term and an exponential term which can present the discharging behavior of a battery. The polynomial term represents the stable discharging behavior and the exponential term represents the unstable discharging behavior. The proposed model proved that the aging of a battery increases with cycle numbers and reflects the variation in the parameters of the model in state of charge (SoC) of a battery. In addition, a simpler algorithm that estimates part of the discharging characteristics to predict SoC of a battery also presented in this work. The algorithm has shorter computing time, higher efficiency and greater convenience. Through the experiments that practical operations, maximum absolute percentage error of SoC for the relationship between measurement and fitting data is 1.83%. The results mean that the proposed model has been verified, demonstrating its effectiveness and accuracy.
2017 IEEE 8th International Conference on Awareness Science and Technology (iCAST), 2017
In this work we examine how the updates addressing Meltdown and Spectre vulnerabilities impact th... more In this work we examine how the updates addressing Meltdown and Spectre vulnerabilities impact the performance of HPC applications. To study this we use the application kernel module of XDMoD to test the performance before and after the application of the vulnerability patches. We tested the performance difference for multiple application and benchmarks including: NWChem, NAMD, HPCC, IOR, MDTest and IMB. The results show that although some specific functions can have perfomance decreased by as much as 74%, the majority of individual metrics indicates little to no decrease in performance. The real-world applications show a 2-3% decrease in performance for single node jobs and a 5-11% decrease for parallel multi node jobs.
2016 IEEE Transportation Electrification Conference and Expo, Asia-Pacific (ITEC Asia-Pacific), 2016
A newly-designed multiport bidirectional power converter is studied to interface battery, superca... more A newly-designed multiport bidirectional power converter is studied to interface battery, supercapacitor and dc-bus of different voltage levels for hybrid electric/fuel-cell vehicle (HEV/FCV) system. The converter can be used to operate in both the step-down and step-up modes with bidirectional power flow control. The operating modes of proposed topology can be classified into low-voltage dual sources powering boost mode and high-voltage dc-link energy-regenerating buck mode. Also, It is possible to independently control power flow between any two low-voltage sources, i.e. low-voltage dual sources buck/boost mode. The operation, analysis, and design of the converter are proposed with different modes of power transfer. Experimental results for a 1-kW system are provided, validating the theoretical analysis.
2015 IEEE 2nd International Future Energy Electronics Conference (IFEEC), 2015
In this paper, a simple modular passive ripple mirror circuit (PRMC) is adopted for eliminating t... more In this paper, a simple modular passive ripple mirror circuit (PRMC) is adopted for eliminating the inherent high frequency current ripple of pulse-width modulated (PWM) DC-DC converters. The PRMC doesn't require any additional active switches, driver circuits or any extra control; the cost can be saved easily. Only the reflected high frequency ripples are automatically induced and processed for proper cancellation with the original ripples. It turns out that not only the output power quality can be enhanced but also the inductance of the main power conversion circuit can be reduced greatly. In this paper, both the circuit structure and operation principle of the PRMC are described. Furthermore, the PRMC technique is then integrated into a family of PWM DC-DC converters, such as buck, boost, Cuk, Zeta, and SEPIC converters. Finally, as the demonstration, experimental results of the Cuk PWM converter integrated with PRMC are provided to verify the feasibility of the principle.
A single-stage ac/dc LLCresonant converter is Experimental results obtained fromanac1lOVline inpu... more A single-stage ac/dc LLCresonant converter is Experimental results obtained fromanac1lOVline input, proposed todrawasinusoidal line current, forachievingand28V/3Aoutput laboratory prototype, arepresented. powerfactor correction (PFC).Theproposed ac/dc Finally, theproposed single-stage LLC-SRCconverter converter composes ofa boost-PFC semi-stage anda successfully meets theIEC1000-3-2 Class-D requirements, LLC-SRCsemi-stage. Theboost-PFC semi-stage, workingandnearly a unity powerfactor. Also,theconversion indiscontinuous conduction mode(DCM)functions asa efficiency canbeachieved upto86%,undera rated powerfactor corrector, andtheLLC-SRCsemi-stage condition. Theseexperimental results areveryattractive as operates abovetheresonance toachieve zero-voltage theory predicts. switching (ZVS)operation. Theproposed converter hasthe feature ofvariable-frequency control, whichprovides a dioderectifier tofeedtheboost-PFC semi-stage. The half-bridge switch pairoperates atasymmetrical ratio D Conven...