The Experts below are selected from a list of 41856 Experts worldwide ranked by ideXlab platform
Yue Wang - One of the best experts on this subject based on the ideXlab platform.
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stability analysis of digitally controlled dual active bridge converters
Journal of Modern Power Systems and Clean Energy, 2018Co-Authors: Ling Shi, Wanjun Lei, L I Zhuoqiang, Yao Cui, Jun Huang, Yue WangAbstract:The dual active bridge (DAB) converters are widely used in the energy Storage Equipment and the distributed power systems. However, the existence of switching nonlinearity and control delay can cause serious stability problem to the DAB converters. Thus, this paper, studies the stability of a digitally controlled DAB converter with an output voltage closed loop controller. Firstly, to accurately study the stability in a DAB converter, a discrete-time model established in a whole switching period is obtained. The model considers the output capacitor ESR, the digital control delay, and sample-and-hold process. By using this model, the stabilities of the DAB converter versus the proportional controller parameter and the output capacitor ESR are analyzed and the critical values are predicted accurately. Moreover, the stability boundary of the proportional controller parameter and the output capacitor ESR is also obtained. The result shows that the value of the output capacitor ESR can have a great effect on the stability region of the proportional controller parameter. Finally, the theoretical analyses are verified by the simulation and experimental results.
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bilinear discrete time modeling and stability analysis of the digitally controlled dual active bridge converter
IEEE Transactions on Power Electronics, 2017Co-Authors: Ling Shi, Wanjun Lei, Yao Cui, Jun Huang, Yue WangAbstract:Dual active bridge (DAB) converters have been widely used in distributed power systems and energy Storage Equipment. However, the inherent nonlinearity of the DAB converters can cause stability problem, such as output voltage oscillation. In this paper, the dynamic behavior and stability of a digitally controlled DAB converter with a closed-loop controller are studied. First, to accurately study the nonlinear dynamics and stability in a DAB converter, a bilinear discrete-time model considering the output capacitor equivalent series resistance (ESR) and the digital control delay in circuit is established. Based on the model, the nonlinear dynamic characteristic and stability of the DAB converter versus the control parameter are studied. Furthermore, extensive analyses are performed to study the effect of the transformer leakage inductance and the output capacitor ESR on the stability boundaries of the control parameter. The accuracy of the model and the theoretical analyses are validated by simulation and experimental results. The proposed model of the digitally controlled DAB converter can accurately predict the stability boundaries, which can be effectively applied to the design of the system parameters and guarantee stable operation of the converter.
Mikihiko Matsui - One of the best experts on this subject based on the ideXlab platform.
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fuzzy logic based v f control of an induction motor for a dc grid power leveling system using flywheel energy Storage Equipment
IEEE Transactions on Industrial Electronics, 2009Co-Authors: Xiangdong Sun, Kanghoon Koh, Byunggyu Yu, Mikihiko MatsuiAbstract:Since natural distribution power generation systems such as wind energy contain electric power fluctuation, flywheel energy Storage (FWES) Equipment for power compensation is used. Fuzzy-logic-based V/f control of the induction motor is proposed for the speed sensorless power-leveling system in this paper. Only two sensors, including one DC voltage sensor and one DC current sensor, are utilized. The flywheel is composed of two modes, namely, the speed picking-up control mode and the power control mode. According to the DC-link average current of an inverter, the rotating speed of the flywheel in the speed picking-up control mode is detected by regulating the output frequency and the output voltage based on fuzzy logic control. The power control mode consists of the outer voltage loop and the inner current loop. Although the outer loop is also realized by fuzzy logic control, the inner loop is the key object in this paper, i.e., the proportional and integral gains of a proportional-integral regulator are optimized by means of fuzzy logic reasoning for the purpose of the reliability and rapid response of leveling power. The experiments are carried out with the FWES Equipment of 40-kJ energy, and the results verify that the proposed method is reliable, and better dynamic and static performance is demonstrated.
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fuzzy logic based v f control of an induction motor for a dc grid power leveling system using flywheel energy Storage Equipment
IEEE Transactions on Industrial Electronics, 2009Co-Authors: Xiangdong Sun, Kanghoon Koh, Mikihiko MatsuiAbstract:Since natural distribution power generation systems such as wind energy contain electric power fluctuation, flywheel energy Storage (FWES) Equipment for power compensation is used. Fuzzy-logic-based V/f control of the induction motor is proposed for the speed sensorless power-leveling system in this paper. Only two sensors, including one DC voltage sensor and one DC current sensor, are utilized. The flywheel is composed of two modes, namely, the speed picking-up control mode and the power control mode. According to the DC-link average current of an inverter, the rotating speed of the flywheel in the speed picking-up control mode is detected by regulating the output frequency and the output voltage based on fuzzy logic control. The power control mode consists of the outer voltage loop and the inner current loop. Although the outer loop is also realized by fuzzy logic control, the inner loop is the key object in this paper, i.e., the proportional and integral gains of a proportional-integral regulator are optimized by means of fuzzy logic reasoning for the purpose of the reliability and rapid response of leveling power. The experiments are carried out with the FWES Equipment of 40-kJ energy, and the results verify that the proposed method is reliable, and better dynamic and static performance is demonstrated.
Ling Shi - One of the best experts on this subject based on the ideXlab platform.
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stability analysis of digitally controlled dual active bridge converters
Journal of Modern Power Systems and Clean Energy, 2018Co-Authors: Ling Shi, Wanjun Lei, L I Zhuoqiang, Yao Cui, Jun Huang, Yue WangAbstract:The dual active bridge (DAB) converters are widely used in the energy Storage Equipment and the distributed power systems. However, the existence of switching nonlinearity and control delay can cause serious stability problem to the DAB converters. Thus, this paper, studies the stability of a digitally controlled DAB converter with an output voltage closed loop controller. Firstly, to accurately study the stability in a DAB converter, a discrete-time model established in a whole switching period is obtained. The model considers the output capacitor ESR, the digital control delay, and sample-and-hold process. By using this model, the stabilities of the DAB converter versus the proportional controller parameter and the output capacitor ESR are analyzed and the critical values are predicted accurately. Moreover, the stability boundary of the proportional controller parameter and the output capacitor ESR is also obtained. The result shows that the value of the output capacitor ESR can have a great effect on the stability region of the proportional controller parameter. Finally, the theoretical analyses are verified by the simulation and experimental results.
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bilinear discrete time modeling and stability analysis of the digitally controlled dual active bridge converter
IEEE Transactions on Power Electronics, 2017Co-Authors: Ling Shi, Wanjun Lei, Yao Cui, Jun Huang, Yue WangAbstract:Dual active bridge (DAB) converters have been widely used in distributed power systems and energy Storage Equipment. However, the inherent nonlinearity of the DAB converters can cause stability problem, such as output voltage oscillation. In this paper, the dynamic behavior and stability of a digitally controlled DAB converter with a closed-loop controller are studied. First, to accurately study the nonlinear dynamics and stability in a DAB converter, a bilinear discrete-time model considering the output capacitor equivalent series resistance (ESR) and the digital control delay in circuit is established. Based on the model, the nonlinear dynamic characteristic and stability of the DAB converter versus the control parameter are studied. Furthermore, extensive analyses are performed to study the effect of the transformer leakage inductance and the output capacitor ESR on the stability boundaries of the control parameter. The accuracy of the model and the theoretical analyses are validated by simulation and experimental results. The proposed model of the digitally controlled DAB converter can accurately predict the stability boundaries, which can be effectively applied to the design of the system parameters and guarantee stable operation of the converter.
Likun Pan - One of the best experts on this subject based on the ideXlab platform.
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a novel redox bromide ion additive hydrogel electrolyte for flexible zn ion hybrid supercapacitors with boosted energy density and controllable zinc deposition
Journal of Materials Chemistry, 2020Co-Authors: Lu Han, Hailong Huang, Zhongli Yang, Xinlu Zhang, Likun PanAbstract:With the rapid development of flexible wearable electronic devices and the growing energy demands of modern society, flexible energy Storage Equipment is attracting increasing attention. Recently, flexible Zn-ion hybrid supercapacitors (ZHSs), as a new type of flexible energy Storage device, have been reported. However, the limited energy density of the currently reported flexible ZHSs should be further improved to realize their large-scale applications. Herein, we designed a novel redox bromide-ion additive hydrogel electrolyte (SA–Zn–Br) for flexible Zn-ion hybrid supercapacitors (BH-ZHSs) via the introduction of extra faradaic contributions (3Br−/Br3−) into the hydrogel electrolyte to improve their energy density. Additionally, the assembled flexible BH-ZHS displays a maximum energy density of 605 W h kg−1 at a power density of 1848 W kg−1 at an amazing voltage of 2.6 V, which is better than that of most reported flexible ZHSs. After a 5000 cycle charge/discharge cycling test, capacity retention of 87.7% is retained. Interestingly, the strong interactions between the charged groups and Zn2+ ion in the SA–Zn–Br hydrogel electrolyte can harmonize Zn2+ migration with uniform nucleation on a Zn foil surface, leading to layered zinc deposition. Additionally, the SA–Zn–Br hydrogel electrolyte can also serve as an inhibitor of water/oxygen, resulting in the mitigation of corrosion and highly reversible zinc stripping/depositing. The strategy described in this study should provide a new insight for exploring flexible ZHSs with boosted energy density and controllable zinc deposition.
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a flexible high voltage and safe zwitterionic natural polymer hydrogel electrolyte for high energy density zinc ion hybrid supercapacitor
Chemical Engineering Journal, 2020Co-Authors: Lu Han, Hailong Huang, Zhongli Yang, Xinjuan Liu, Likun PanAbstract:Abstract With the development of flexible wearable electronic devices, energy Storage Equipment like supercapacitor with high energy density, good mechanical properties and safety has attracted more and more attention. However, the currently existing energy Storage materials normally suffer from several drawbacks, such as poor flexibility, hidden danger, toxicity and especially low energy density, limiting their practical applications. Expanding the voltage window by employing the hydrogel electrolyte is regarded as an effective method to improve the energy density of supercapacitor. Herein, we employ a zwitterionic natural polymer hydrogel with excellent mechanical strength and flexibility as electrolyte to assemble a solid-state zinc-ion hybrid supercapacitor (H-ZHS) with Zn foil and activated carbon electrode. The H-ZHS exhibits an amazingly wide and stable voltage window of 2.4 V, high maximum energy density of 286.6 Wh kg−1 at the power density of 220 W kg−1 and superior capacity retention of 95.4% after 2000 cycles at 2 A g−1 calculated based on mass of activated carbon electrode. The strategy in this work should provide a new insight in exploring zinc-ion hybrid supercapacitor with high energy density for flexible wearable electronic devices.
Xiangdong Sun - One of the best experts on this subject based on the ideXlab platform.
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fuzzy logic based v f control of an induction motor for a dc grid power leveling system using flywheel energy Storage Equipment
IEEE Transactions on Industrial Electronics, 2009Co-Authors: Xiangdong Sun, Kanghoon Koh, Byunggyu Yu, Mikihiko MatsuiAbstract:Since natural distribution power generation systems such as wind energy contain electric power fluctuation, flywheel energy Storage (FWES) Equipment for power compensation is used. Fuzzy-logic-based V/f control of the induction motor is proposed for the speed sensorless power-leveling system in this paper. Only two sensors, including one DC voltage sensor and one DC current sensor, are utilized. The flywheel is composed of two modes, namely, the speed picking-up control mode and the power control mode. According to the DC-link average current of an inverter, the rotating speed of the flywheel in the speed picking-up control mode is detected by regulating the output frequency and the output voltage based on fuzzy logic control. The power control mode consists of the outer voltage loop and the inner current loop. Although the outer loop is also realized by fuzzy logic control, the inner loop is the key object in this paper, i.e., the proportional and integral gains of a proportional-integral regulator are optimized by means of fuzzy logic reasoning for the purpose of the reliability and rapid response of leveling power. The experiments are carried out with the FWES Equipment of 40-kJ energy, and the results verify that the proposed method is reliable, and better dynamic and static performance is demonstrated.
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fuzzy logic based v f control of an induction motor for a dc grid power leveling system using flywheel energy Storage Equipment
IEEE Transactions on Industrial Electronics, 2009Co-Authors: Xiangdong Sun, Kanghoon Koh, Mikihiko MatsuiAbstract:Since natural distribution power generation systems such as wind energy contain electric power fluctuation, flywheel energy Storage (FWES) Equipment for power compensation is used. Fuzzy-logic-based V/f control of the induction motor is proposed for the speed sensorless power-leveling system in this paper. Only two sensors, including one DC voltage sensor and one DC current sensor, are utilized. The flywheel is composed of two modes, namely, the speed picking-up control mode and the power control mode. According to the DC-link average current of an inverter, the rotating speed of the flywheel in the speed picking-up control mode is detected by regulating the output frequency and the output voltage based on fuzzy logic control. The power control mode consists of the outer voltage loop and the inner current loop. Although the outer loop is also realized by fuzzy logic control, the inner loop is the key object in this paper, i.e., the proportional and integral gains of a proportional-integral regulator are optimized by means of fuzzy logic reasoning for the purpose of the reliability and rapid response of leveling power. The experiments are carried out with the FWES Equipment of 40-kJ energy, and the results verify that the proposed method is reliable, and better dynamic and static performance is demonstrated.
