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- 摘要
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- 实验方案
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Design of Efficient Resonator-Enhanced Electro-Optic Frequency Comb Generators
摘要： This paper proposes a direct double-frequency ripple current control in a single-phase high-power fuel cell converter that can achieve low-frequency ripple-free input current without using large electrolytic capacitors. To eliminate the double-frequency ripple current disturbance introduced by the single-phase inverter load, a proportional–resonant controller is developed to achieve an extra high control gain at designed resonant frequency. This high gain can be viewed as the virtual high impedance for blocking the double-frequency ripple energy propagation from inverter load to fuel cell stack. More particularly, the proposed control system can realize the utilization of all capacitive ripple energy sources in the system by regulating all the capacitors to have large voltage swing. In addition, this voltage swing is synchronized to keep real-time balancing of the transformer primary- and secondary-side voltages. As a result, the zero-voltage-switching operation for all switching devices in the dc–dc stage can be guaranteed. The controller design guidelines are derived based on the system small-signal model. The experimental results are presented to validate the theoretical analysis and proposed technology.
关键词： Current-fed three-phase dc–dc converter,fuel cell,direct double-frequency ripple current control,electrolytic capacitor free,zero voltage switching (ZVS)
更新于2025-09-23 15:21:01
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72.3 W 1064 nm Nd:YAG Single Crystal Fiber Laser and Intracavity Double Frequency Generation
摘要： As a bridge between crystal and fiber, the single crystal fiber (SCF) can combine the advantages of the two materials and show great potential in high-power lasers. In this paper, we select a Nd:YAG SCF as the gain medium in a diode-end-pumped linear cavity. The Nd:YAG SCF with the dimensions of ? = 1 mm × 50 mm was manufactured using the micro-pulling-down technique. At an incident pump power of 153.0 W, the maximum output power of the 1064 nm laser was 72.3 W. To the best of our knowledge, this is the highest power obtained in Nd:YAG SCF lasers. In addition, using a second-type phase-matched KTP crystal, the 10 W continuous wave green laser was obtained with an intracavity double-frequency structure.
关键词： single crystal fiber,high power,diode-end-pumped laser,double frequency
更新于2025-09-23 15:21:01
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Pedestal substrate integrated waveguide filter with both electric and magnetic cross-couplings
摘要： In single-phase photovoltaic (PV) system, there is double-frequency power mismatch existed between the dc input and ac output. The double-frequency ripple (DFR) energy needs to be buffered by passive network. Otherwise, the ripple energy will flow into the input side and adversely affect the PV energy harvest. In a conventional PV system, electrolytic capacitors are usually used for this purpose due to their high capacitance. However, electrolytic capacitors are considered to be one of the most failure prone components in a PV inverter. In this paper, a capacitance reduction control strategy is proposed to buffer the DFR energy in single-phase Z-source/quasi-Z-source inverter applications. Without using any extra hardware components, the proposed control strategy can significantly reduce the capacitance requirement and achieve low input voltage DFR. Consequently, highly reliable film capacitors can be used. The increased switching device voltage stress and power loss due to the proposed control strategy will also be discussed. A 1-kW quasi-Z-source PV inverter using gallium nitride (GaN) devices is built in the lab. Experimental results are provided to verify the effectiveness of the proposed method.
关键词： Capacitance reduction,double-frequency ripple (DFR),Z-source (ZS)/quasi-Z-source (qZS)
更新于2025-09-16 10:30:52