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Hungliang Cheng - One of the best experts on this subject based on the ideXlab platform.

  • modeling and design of the llc resonant converter used as a Solar Array simulator
    IEEE Journal of Emerging and Selected Topics in Power Electronics, 2014
    Co-Authors: Chienhsuan Chang, Chunan Cheng, Hungliang Cheng
    Abstract:

    The LLC resonant converter has been used to implement a Solar-Array simulator with high-efficiency and fast-response features. In this paper, its small-signal model is derived based on the extended describing function concept. The corresponding frequency response can be easily obtained from IsSPICE simulation of the equivalent circuit model. The derived model is matching with the measured results very well. Furthermore, a Solar-Array simulator with closed-loop control is designed according to the derived small-signal model. The experimental measurements have really proved that high-efficiency and fast-transient responses can be achieved in the system. The output voltage and output current can be adjusted simultaneously to match the electrical characteristics of photovoltaic output.

  • a high efficiency Solar Array simulator implemented by an llc resonant dc dc converter
    IEEE Transactions on Power Electronics, 2013
    Co-Authors: Chienhsuan Chang, Enchih Chang, Hungliang Cheng
    Abstract:

    In this paper, a high-efficiency Solar Array simulator (SAS) implemented by an LLC resonant dc-dc converter is proposed to save the cost and energy of photovoltaic (PV) system testing. The proposed converter has zero-voltage switching (ZVS) operation of the primary switches and zero-current switczero-current switching (ZCS) operation of the rectifier diodes. By frequency modulation control, the outputhing (ZCS) operation of the rectifier diodes. By frequency modulation control, the output impedance of an LLC resonant converter can be regulated from zero to infinite without shunt or serial resistors. Therefore, the efficiency of the proposed SAS can be significantly increased. The circuit operations are analyzed in detail to derive the theoretical equations. Circuit parameters are designed based on the practical considerations. Finally, an illustrative example is implemented to demonstrate the feasibility of the proposed SAS.

Chienhsuan Chang - One of the best experts on this subject based on the ideXlab platform.

  • modeling and design of the llc resonant converter used as a Solar Array simulator
    IEEE Journal of Emerging and Selected Topics in Power Electronics, 2014
    Co-Authors: Chienhsuan Chang, Chunan Cheng, Hungliang Cheng
    Abstract:

    The LLC resonant converter has been used to implement a Solar-Array simulator with high-efficiency and fast-response features. In this paper, its small-signal model is derived based on the extended describing function concept. The corresponding frequency response can be easily obtained from IsSPICE simulation of the equivalent circuit model. The derived model is matching with the measured results very well. Furthermore, a Solar-Array simulator with closed-loop control is designed according to the derived small-signal model. The experimental measurements have really proved that high-efficiency and fast-transient responses can be achieved in the system. The output voltage and output current can be adjusted simultaneously to match the electrical characteristics of photovoltaic output.

  • a high efficiency Solar Array simulator implemented by an llc resonant dc dc converter
    IEEE Transactions on Power Electronics, 2013
    Co-Authors: Chienhsuan Chang, Enchih Chang, Hungliang Cheng
    Abstract:

    In this paper, a high-efficiency Solar Array simulator (SAS) implemented by an LLC resonant dc-dc converter is proposed to save the cost and energy of photovoltaic (PV) system testing. The proposed converter has zero-voltage switching (ZVS) operation of the primary switches and zero-current switczero-current switching (ZCS) operation of the rectifier diodes. By frequency modulation control, the outputhing (ZCS) operation of the rectifier diodes. By frequency modulation control, the output impedance of an LLC resonant converter can be regulated from zero to infinite without shunt or serial resistors. Therefore, the efficiency of the proposed SAS can be significantly increased. The circuit operations are analyzed in detail to derive the theoretical equations. Circuit parameters are designed based on the practical considerations. Finally, an illustrative example is implemented to demonstrate the feasibility of the proposed SAS.

  • a high efficiency Solar Array simulator implemented by an llc resonant dc dc converter
    The International Power Electronics Conference - ECCE ASIA, 2010
    Co-Authors: Chienhsuan Chang, C W Ku
    Abstract:

    In order to save the cost and energy for PV system testing, a high efficiency Solar Array simulator (SAS) implemented by an LLC resonant DC/DC converter is proposed. This converter has zero voltage switching (ZVS) operation of the primary switches and zero current switching (ZCS) operation of the rectifier diodes. By frequency modulation control, the output impedance of an LLC converter can be regulated from zero to infinite without shunt or series resistor; hence, the efficiency of the proposed SAS can be significantly increased. According to the provided operation principles and design considerations of an LLC converter, a prototype is implemented to demonstrate the feasibility of the proposed SAS.

Junhui Meng - One of the best experts on this subject based on the ideXlab platform.

  • Optimization design of a thermal protection structure for the Solar Array of stratospheric airships
    Renewable Energy, 2019
    Co-Authors: Junhui Meng, Zhongbing Yao, Siyu Liu, Ming Yun Lv
    Abstract:

    Abstract Renewable power system using Solar Array is one of the most critical subsystems for stratospheric airships. It is important of thermal protection for the stratospheric airship, because excessive temperature of Solar cell may reduce its conversion efficiency and age the envelope material underlaid Solar cells. Multi-objective optimization of a thermal protection structure with heat dissipation and insulation layers for Solar Array of a stratospheric airship is performed in this paper. The optimization process is carried out by a Nondominated Sorting Genetic Algorithm to decrease the sensitivity toward weights or demand levels. The specific temperature difference, which indicates the ratio of temperature reduction and structure density, and the output power of Solar Array are used to present the optimization aims. Three geometric variables related to the number of fins, width ratio of fins and thickness ratio of dissipation and insulation layer are selected as the design variables. Pareto optimal fronts representing the trade-offs between the performance parameters are obtained at last and optimization results are compared with previous studies and the thermal protection effects and output power of the Solar Array are both more excellent. Furthermore, the simulation of the thermal protection structure with optimization parameters are carried out at last.

  • a theoretical study of rotatable renewable energy system for stratospheric airship
    Energy Conversion and Management, 2017
    Co-Authors: Jun Li, Weiyu Zhu, Huafei Du, Junhui Meng, Kangwen Sun
    Abstract:

    Abstract Renewable energy system is very critical for solving the energy problem of a long endurance stratospheric airship. Output performance of the traditional Solar Array fixed on the upper surface of the airship remains to be improved to reduce the area and weight of renewable energy system. Inspired by the Solar tracking system and kirigami, a rotatable renewable energy system (mainly including Solar Array) is designed to improve the current status of the energy system. The advantages of the rotatable Solar Array are studied using a MATLAB computer program based on the theoretical model established in this paper. The improvements in output energy and required area of the Solar Array were compared between the traditional airship and improved one. Studies had shown that the rotatable renewable energy system made the total weight of energy system decreased by 1000 kg when the maximum design speed of the airship was greater than 22 m/s. The results demonstrate that the rotatable renewable energy system for the airship can be a good way to improve the output performance of Solar Array, and the conceptual design and theoretical model suggest a pathway towards solving the energy problem of a stratospheric airship.

  • Solar Array layout optimization for stratospheric airships using numerical method
    Energy Conversion and Management, 2017
    Co-Authors: Ming Yun Lv, Huafei Du, Jun Li, Junhui Meng
    Abstract:

    Abstract The Solar Array layout is one of the critical factors affecting the output performance of a Solar Array on a stratospheric airship. Optimizing the layout to improve output energy per day is very important for a long endurance vehicle, but the research about this subject is rare. This paper outlines a numerical method based on a rotating model of a stratospheric airship to optimize the Solar Array layout. Combined with the Solar radiation model, the Solar Array layout optimization model applying genetic algorithm is developed using a MATLAB computer program in this paper. Compared with the design parameters of three stratospheric Solar-powered airships, the theoretical model is proved to be feasible. In the course of the study, the effects of the starting point and the central angle of Solar Array are discussed in detail. In addition, the optimal results of the Solar Array layout for four common situations are investigated using the method. The results indicate that this method is helpful in the preparation stage for installing large area flexible Solar Arrays.

  • Thermal protection method of the Solar Array for stratospheric airships
    Applied Thermal Engineering, 2017
    Co-Authors: Junhui Meng, Zhongbing Yao, Huafei Du, Ming Yun Lv
    Abstract:

    Abstract Part of the sunlight energy received by the Solar Array on the stratospheric airship surface is converted to electric energy, and considerable energy is transformed into heat, which is bad for the envelope material and the internal pressure of the airship. It is necessary to develop different methods for the Solar Array to reduce its thermal effects on the stratospheric airship. Coating film, heat dissipation structure and heat insulation structure are developed to reduce the thermal effects. A series of theoretical studies are carried out to analyze the effects of three layers, especially the heat dissipation structure made up by Arrayed fins, which are verified by the experimental test and CFD simulation. As for the Solar Array system, the mutual coordination among output power, thermal protection effect and the structure weight ought to be considered at the same time in the design of Solar Array system of the stratospheric airship.

Ming Yun Lv - One of the best experts on this subject based on the ideXlab platform.

  • Optimization design of a thermal protection structure for the Solar Array of stratospheric airships
    Renewable Energy, 2019
    Co-Authors: Junhui Meng, Zhongbing Yao, Siyu Liu, Ming Yun Lv
    Abstract:

    Abstract Renewable power system using Solar Array is one of the most critical subsystems for stratospheric airships. It is important of thermal protection for the stratospheric airship, because excessive temperature of Solar cell may reduce its conversion efficiency and age the envelope material underlaid Solar cells. Multi-objective optimization of a thermal protection structure with heat dissipation and insulation layers for Solar Array of a stratospheric airship is performed in this paper. The optimization process is carried out by a Nondominated Sorting Genetic Algorithm to decrease the sensitivity toward weights or demand levels. The specific temperature difference, which indicates the ratio of temperature reduction and structure density, and the output power of Solar Array are used to present the optimization aims. Three geometric variables related to the number of fins, width ratio of fins and thickness ratio of dissipation and insulation layer are selected as the design variables. Pareto optimal fronts representing the trade-offs between the performance parameters are obtained at last and optimization results are compared with previous studies and the thermal protection effects and output power of the Solar Array are both more excellent. Furthermore, the simulation of the thermal protection structure with optimization parameters are carried out at last.

  • Solar Array layout optimization for stratospheric airships using numerical method
    Energy Conversion and Management, 2017
    Co-Authors: Ming Yun Lv, Huafei Du, Jun Li, Junhui Meng
    Abstract:

    Abstract The Solar Array layout is one of the critical factors affecting the output performance of a Solar Array on a stratospheric airship. Optimizing the layout to improve output energy per day is very important for a long endurance vehicle, but the research about this subject is rare. This paper outlines a numerical method based on a rotating model of a stratospheric airship to optimize the Solar Array layout. Combined with the Solar radiation model, the Solar Array layout optimization model applying genetic algorithm is developed using a MATLAB computer program in this paper. Compared with the design parameters of three stratospheric Solar-powered airships, the theoretical model is proved to be feasible. In the course of the study, the effects of the starting point and the central angle of Solar Array are discussed in detail. In addition, the optimal results of the Solar Array layout for four common situations are investigated using the method. The results indicate that this method is helpful in the preparation stage for installing large area flexible Solar Arrays.

  • Thermal protection method of the Solar Array for stratospheric airships
    Applied Thermal Engineering, 2017
    Co-Authors: Junhui Meng, Zhongbing Yao, Huafei Du, Ming Yun Lv
    Abstract:

    Abstract Part of the sunlight energy received by the Solar Array on the stratospheric airship surface is converted to electric energy, and considerable energy is transformed into heat, which is bad for the envelope material and the internal pressure of the airship. It is necessary to develop different methods for the Solar Array to reduce its thermal effects on the stratospheric airship. Coating film, heat dissipation structure and heat insulation structure are developed to reduce the thermal effects. A series of theoretical studies are carried out to analyze the effects of three layers, especially the heat dissipation structure made up by Arrayed fins, which are verified by the experimental test and CFD simulation. As for the Solar Array system, the mutual coordination among output power, thermal protection effect and the structure weight ought to be considered at the same time in the design of Solar Array system of the stratospheric airship.

Donglai Zhang - One of the best experts on this subject based on the ideXlab platform.

  • high power high dynamic performance space Solar Array simulator using step wave tracking output voltage approach
    IEEE Transactions on Power Electronics, 2018
    Co-Authors: Donglai Zhang, Lu Qu, Xiaofeng Zhang, Yu Gu
    Abstract:

    With the power of high-orbit satellites now reaching dozens of kilowatts, Solar energy sources play an important role in nonterrestrial applications. However, most of the existing high-power Solar Array simulators (SASs) are designed for simulating energy sources in terrestrial applications, and may not have suitable dynamic performance for nonterrestrial applications. This paper proposes a design for a high-power high-dynamic-performance space Solar Array simulator (SSAS) system, which combines a linear power stage unit and a multilevel bus tracking converter unit, in order to achieve a fast step-switching capability and high-power-handling capacity. In this paper, we consider the SSAS power system as two separate parts: the I–V power curve simulator that uses a linear power stage with 20 linear voltage-controlled current paths in parallel; and the multilevel bus tracking converter unit that provides the variable voltage levels tracking the SSAS output voltage, in order to decrease the power dissipation in the linear power stage. This paper establishes a mathematical model for the multilevel converter under this particular system architecture, and presents the application qualification conditions and system design principles. The proposed 2.4-kW SSAS can react quickly to a load step between the short-circuit and open-circuit states, which are the most challenging working conditions, at a stepping frequency of 3 kHz; this is a superior dynamic performance compared to other similar devices. The experimental results of testing the spacecraft power supply with a shunt regulator architecture demonstrating better performance, when compared to the results from four SAS modular products in parallel.

  • high dynamic performance Solar Array simulator based on a sic mosfet linear power stage
    IEEE Transactions on Power Electronics, 2018
    Co-Authors: Donglai Zhang
    Abstract:

    The power conditioning unit system is a critical part in a spacecraft and is responsible for converting the Solar panel energy into a stable bus voltage. This system requires a high dynamic characteristic Solar Array simulator (SAS) for testing purposes. Space Solar Array simulators (SSASs) used for testing space power systems generally use a linear power topology because of its fast dynamic performance and good simulation accuracy. However, commercially available SASs are not sufficiently fast for simulating the actual Solar Array panel output and, therefore are unreliable for terrestrial testing. In this paper, a highly dynamic SSAS is developed with multipath SiC MOSFET linear voltage-controlled current source paralleling for power regulation. The proposed 510 W SSAS, consisting of 20 linear current paths paralleling the power stage and a high-speed FPGA digital controller, can quickly react to a load step between the nominal and short circuit at 50-kHz stepping frequency. It can also react to a step change from a short circuit to an open circuit perfectly at a 1-kHz stepping frequency offering a superior dynamic performance compared to other similar devices.

  • influence of multijunction ga as Solar Array parasitic capacitance in s3r and solving methods for high power applications
    IEEE Transactions on Power Electronics, 2014
    Co-Authors: Hongyu Zhu, Donglai Zhang
    Abstract:

    This paper deals with the influence produced by the Solar Array parasitic capacitance and its solving methods in the sequential switching shunt regulator (S3R). Nowadays, the usage of triple-junction Ga/As Solar cells with larger parasitic capacitance has prompted new problems about power losses, steady state, and dynamic response in the S3R, especially for high section current, voltage applications. Effects of parasitic capacitance on voltage ripple, “double sectioning,” phase margin, and output impedance are represented and analyzed, and turn-off delay caused by parasitic capacitance is mathematically modeled. A novel shunt regulator topology passive and active shunt regulator (PASR) with low switching losses, low mass, and short turn-off time delay is proposed. To further reduce the impact of delay, nonlinear control is added in the control loop, achieving better performances in the stability margin, output impedance, and dynamic performance. Simulation and experimental results are provided to validate the proposed PASR together with nonlinear control scheme.