- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Portland, OR, USA (2018.9.23-2018.9.27)] 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - A Comprehensive Comparison of MHz GaN-Based ZVS Step-Down Converters for Low Power Integrated On-Chip Applications
摘要： Non-isolated step-down converters are widely used as auxiliary power supplies. Active and passive components are usually integrated in a single chip in the industry. High power density and high efficiency are always the most important requirements. High switching frequency, such as megahertz (MHz), can highly shrink the volume of passive components compared with kilohertz frequency, however, it will cause huge switching loss for hard switching converters. Zero-voltage-switching (ZVS) is able to highly reduce switching loss, especially under high frequency. In this paper, three ZVS buck-type converters operating at MHz frequency, including conventional buck, tapped-inductor buck and hybrid resonant buck converter, are compared. Finally, three hardware prototypes using gallium-nitride (GaN) devices with 24-48 V input and 3-A/5-V output are demonstrated and compared in terms of efficiency, size and thermal performance.
关键词： megahertz switching frequency.,soft-switching,step-down converter,non-isolated
更新于2025-09-23 15:23:52
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Improved three-vector based dead-beat model predictive direct power control strategy for grid-connected inverters
摘要： Since only one inverter voltage vector is applied during each duty cycle, traditional model predictive direct power control (MPDPC) for grid-connected inverters (GCIs) results in serious harmonics in current and power. Moreover, a high sampling frequency is needed to ensure satisfactory steady-state performance, which is contradictory to its long execution time due to the iterative prediction calculations. To solve these problems, a novel dead-beat MPDPC strategy is proposed, using two active inverter voltage vectors and one zero inverter voltage vector during each duty cycle. Adoption of three inverter vectors ensures a constant switching frequency. Thus, smooth steady-state performance of both current and power can be obtained. Unlike the traditional three-vector based MPDPC strategy, the proposed three vectors are selected based on the power errors rather than the sector where the grid voltage vector is located, which ensures that the duration times of the selected vectors are positive all the time. Iterative calculations of the cost function in traditional predictive control are also removed, which makes the proposed strategy easy to implement on digital signal processors (DSPs) for industrial applications. Results of experiments based on a 1 kW inverter setup validate the feasibility of the proposed three-vector based dead-beat MPDPC strategy.
关键词： Grid-connected inverter,Model predictive control,Constant switching frequency,Power errors,Direct power control,Three vectors
更新于2025-09-23 15:23:52
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[IEEE IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society - D.C., DC, USA (2018.10.21-2018.10.23)] IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society - Controller-Hardware-in-the-Loop Testbed for Fast-Switching SiC-Based 50-kW PV Inverter
摘要： The recent advent of wide bandgap power semiconductor devices will lay the path for future power converters. These devices provide the advantage of high switching speed and lower losses. The high cost and high switching speeds of these devices provide a challenge in the development and validation of the fast-switching inverter controls with accuracy comparable to that of a hardware setup. In this paper, a field programmable gate array (FPGA) real-time simulator-based controller-hardware-in-the-loop (CHIL) testbed is used to verify the low-level and advanced inverter controls for fast-switching wide bandgap-based photovoltaic string inverter. The paper also includes development of the CHIL testbed, which is run at a time step of 500 ns in order to implement 20-kHz switching frequency. The developed CHIL testbed is validated through experimental results from a three-phase, 50-kW, 480-VLLrms SiC device-based inverter.
关键词： controller hardware-in-the-loop,high switching frequency,SiC devices,power electronics converters,advanced grid-support functions
更新于2025-09-23 15:22:29
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Communication Compact CRLH Leaky-wave Antenna using TE20 Mode Substrate Integrated Waveguide for Broad Space Radiation Coverage
摘要： This paper introduces a combinational modulation method to be used in classic full-bridge single phase inverters. The proposed method eliminates even-order harmonics at the pulse width modulation (PWM) stage in the control section, unlike the conventional method of even order harmonic cancelation in the power stage, and offers a cost-effective design by switching one leg at high frequency. Using a low-cost digital signal controller platform, a regular sampling technique based on real-time calculation was employed to verify the feasibility of the proposed method on a 500-W single phase voltage source inverter. Performance characteristics, such as switching losses and harmonic distortions, are presented for the new approach and compared with a classic inverter modulation method.
关键词： switching frequency,Combinational logic circuits,inverters,pulse width modulation (PWM),silicon carbide,harmonic distortion
更新于2025-09-23 15:19:57
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[IEEE 2019 8th International Conference on Power Systems (ICPS) - Jaipur, India (2019.12.20-2019.12.22)] 2019 8th International Conference on Power Systems (ICPS) - An Efficient LLC Resonant Converter Design for Photovoltaic Application
摘要： This paper presents a novel design procedure to the LLC resonant converter for improve the ef?ciency of photovoltaic (PV) applications. State of the art LLC resonant converter operates either in buck or boost mode by operating at a switching frequency higher or lower than the resonant frequency respectively. However, such operation of the converter at a switching frequency other than the resonant frequency may result in increased turn off losses for MOSFET, conduction losses, and hard commutation for the recti?er diodes which reduces the ef?ciency of the converter. In this paper, a design procedure is proposed where the converter operates very close to the resonant frequency (10% margin) in buck and boost mode of operation to improve the ef?ciency of the converter. The design procedure mainly involves the control of the transformer tap ratio such that the converter operates near the resonant frequency. Since the transformer tap changing control is slow in nature, the proposed control strategy is mainly suited for photovoltaic application where the input voltage to the converter does not change rapidly during the daytime. The transformer tap control is suggested based on the historical data for solar energy, i.e. recorded temperature and solar irradiance. On changing the transformer tap ratio according to the input voltage, the switching frequency is observed to be moving towards the resonant frequency of the LLC resonant converter. Simulations for both the boost and buck mode operation of the resonant tank of the converter are performed, and with the proposed control higher ef?ciency is achieved for PV applications.
关键词： switching frequency,conduction losses,LLC Resonant Converter,turn-off losses
更新于2025-09-23 15:19:57
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Enhanced Power Output from the PV with Low Input Ripple DC-DC Converter
摘要： The primary objective of Maximum Power Point Tracking (MPPT) for PV systems connected to a low-voltage DC grid is to extract the maximum possible power output from the PV array. Normally high-frequency switched mode power converters are employed to track the maximum power. These converters, however, impose switching frequency voltage ripple on the PV output. This causes fluctuation around the Maximum Power Point (MPP) and results in power loss. These losses can be reduced using electrolytic capacitors, however, the electrolytic capacitors’ lifespan is relatively shorter than that of a PV panel. In this paper, an interleaved boost converter is used to reduce high-frequency voltage ripple introduced on panel. Hence, smaller values of longer lifespan capacitors such as film capacitors will be sufficient to curtail the smaller ripple. Moreover, film capacitors are selected based on voltage ripple. Analysis was carried out for calculating voltage ripple imposed on PV module to select input filter more precisely. In addition, reduction in the voltage ripple is calculated quantitatively and is compared with that of a conventional boost converter. Enhanced power output from the PV panel is mathematically proven and experimentally demonstrated.
关键词： photovoltaic panel,switching frequency voltage ripple,PV output power,electrolytic capacitors,film capacitor,maximum power point tracking (MPPT),interleaved boost converter (IBC),low-voltage dc grid,DC-DC converter,photovoltaic (PV) system
更新于2025-09-19 17:15:36
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Generation of Frequency Combs by Quantum Cascade Lasers Emitting in the 8-μm Wavelength Range
摘要： We have studied the generation of frequency combs by quantum cascade lasers (QCLs) emitting in the 8-μm wavelength range. Results showed the presence of a self-pulsation regime near the lasing threshold. Further increase in the pumping current led to a sharp increase in width of the lasing spectrum, which allowed us to obtain frequency combs with a spectral width exceeding 1.5 THz. This behavior of QCLs can be explained by radiation absorption at the stripe edge that is related to the penetration of waveguide mode into unpumped regions.
关键词： quantum cascade laser,mode locking,Q-switching,frequency comb
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE International Conference on Automatic Control and Intelligent Systems (I2CACIS) - Selangor, Malaysia (2019.6.29-2019.6.29)] 2019 IEEE International Conference on Automatic Control and Intelligent Systems (I2CACIS) - Limiting THD of Grid Connected Photovoltaic System using PWM Switching Frequency Selection Based on Solar Irradiance Changing
摘要： Photovoltaic (PV) system becomes the best alternative energy to produce electricity that can replace fuel resource. Grid Connected Photovoltaic (GC-PV) system will supply the AC power generated to the utility grid then distributed to the consumer. Solar irradiance in Malaysia varies daily and throughout the year. The consequence of low irradiance level is the output of the PV array is low and thus the input of the inverter relatively becoming low. The inverter will exhibit large non-linearity when the inverter is operating at low power input during low level of solar irradiance and Total Harmonic Distortion (THD) will increased. Pulse Width Modulation (PWM) techniques that are Continuous Pulse Width Modulation (CPWM) and Discontinuous PWM (DPWM) are implemented in the inverter control of the GC-PV system using MATLAB/Simulink environment to investigate the effect of switching frequency on THD at different level of solar irradiance. THD is limit within standard requirement by selecting appropriate value of switching frequency. Results shows that CPWM has better performance in THD and switching losses at selected switching frequency.
关键词： total harmonic distortion,inverter,pulse width modulation,switching frequency,grid connected photovoltaic,solar irradiance
更新于2025-09-11 14:15:04