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Low Complexity MIMO Precoder Design with LDL Channel Decomposition
No full text[[abstract]]We present a new multiple-input-multiple-output (MIMO) precoding scheme using LDLH channel decomposition. The proposed method is verified to have lower complexity and better bit-error-rate (BER) performance than that of conventional singular-value decomposition (SVD). SVD is commonly used to decompose the MIMO channel into parallel eigenmodes. However, the large variation of the singular values often leads to ill-conditioned channel and degraded error performance. Recently, two SVD-based decomposition schemes that aim to improve such subchannel gain uniformity have been developed. They are geometric mean decomposition (GMD) and uniform channel decomposition (UCD). Albeit the error performance of GMD and UCD is optimized, both of them require relatively higher complexity than that of SVD with power allocation. In this paper, we present a scheme with moderate subchannel gain uniformity while exhibiting the lowest complexity compared with that of SVD, GMD, and UCD. Simulations also show that LDLH can outperform all aforementioned schemes as the channel-estimation errors in the receiver become severe.[[fileno]]2030122010011[[department]]電機工程學
Power Loss Comparison of Single- and Two-Stage Grid-Connected Photovoltaic Systems
No full text[[abstract]]This paper presents power loss comparison of single- and two-stage grid-connected photovoltaic (PV) systems based on the loss factors of double line-frequency voltage ripple (DLFVR), fast irradiance variation + DLFVR, fast dc load variation + DLFVR, limited operating voltage range + DLFVR, and overall loss factor combination. These loss factors will result in power deviation from the maximum power points. In this paper, both single-stage and two-stage grid-connected PV systems are considered. All of the effects on a two-stage system are insignificant due to an additional maximum power point tracker, but the tracker will reduce the system efficiency typically about 2.5%. The power loss caused by these loss factors in a single-stage grid-connected PV system is also around 2.5%; that is, a single-stage system has the merits of saving components and reducing cost, and does not penalize overall system efficiency under certain operating voltage ranges. Simulation results with the MATLAB software package and experimental results have confirmed the analysis.[[fileno]]2030197010004[[department]]電機工程學
Interleaving Phase Shifters for Critical-Mode Boost PFC
No full text[[abstract]]Interleaving control schemes are widely used in converter applications. Merits of such control methods are in reducing input/output current or voltage ripples and volume, and increasing the processed power capacity of converters. For converters with constant frequency operation, it is easy to achieve interleaving control. However, it is difficult to realize interleaving features with variable frequency operation, such as boost-type power factor correctors (PFCs) operated in critical-mode (CM) condition. This paper proposes several interleaving phase shifters for CM boost PFCs. Analysis and design of the interleaving phase shifters are first described in detail. Moreover, simulated results of the CM boost PFCs with interleaving two-phase and four-phase shifters; are introduced. Finally, experimental results of a two-phase interleaved CM boost PFC are presented to verify the discussed features.[[fileno]]2030197010012[[department]]電機工程學
A Parallel-APF System with Current Sharing Controller and Load-Path Control Center to Improve Dynamic Response and Achieve Weighting Current Distribution
No full text[[abstract]]This paper presents design and implementation of a paralleled active power filter (APF) system with current sharing controller (CSC) and load-path control center (LPCC). This system can filter harmonic currents, compensate reactive power and improve power factor. In the system, each APF module is directly tied to the load, source and buses, and there is no communication between modules. Through CSC and LPCC, the modules can share the total reactive and harmonic currents of the load according to their power ratings. With the proposed control scheme, power capacity of the system can be readily and flexibly expanded. Since there is no communication between modules, system expandability and flexibility will increase, and a hot-swap feature can be readily achieved. Simulation and experimental results have verified the feasibility and performance of the proposed parallel-APF system.[[fileno]]2030197010018[[department]]電機工程學
A Single-Stage Fast Regulator with PFC Based on an Asymmetrical Half-Bridge Topology
No full text[[abstract]]This paper presents single-stage regulators with power-factor correction (PFC) based on an asymmetrical half-bridge topology. The proposed regulator is formed from a boost converter with two coupled inductors and an asymmetrical half-bridge converter with the synchronous switch technique, and it is controlled with pulsewidth modulation to achieve zero-voltage switching (ZVS). The boost converter is operated in discontinues conduction mode to achieve PFC. With the coupled inductors, input current ripple and power factor can be improved significantly. The proposed regulator has the features of constant-frequency operation, ZVS, and low voltage stress imposed on the active switches. Moreover, the regulator can achieve high power factor, high power density, high efficiency, low switching loss, and low component count, which makes its applications at medium-power levels feasible. Experimental results have verified the discussed features of the proposed regulator.[[fileno]]2030197010032[[department]]電機工程學
具自動參數調整之家畜致昏器研製
No full text[[abstract]]本文主要在說明一具自動參數調整之家畜致昏器的研製。研究中首先探討家畜致昏機制，並由瞭解家畜致昏過程對屠體之影響，來決定家畜致昏時所需之電氣參數。緊接著設計一供電系統，以產生致昏家畜的電氣參數，並藉由單晶片，來管理此供電系統，達成具自動參數調整之市電與電池皆能使用之供電系統。此外，在市電供電系統中，加入主動式功因校正器，使電源電流符合功率因數與諧波的規範。最後，以硬體實作及實際豬隻致昏的結果，來驗證此家畜致昏器之可行性。[[fileno]]2030197010039[[department]]電機工程學
SU8 3D prisms with ultra small inclined angle for lowinsertion- loss fiber/waveguide interconnection
Get PDF[[abstract]]This paper presents a simple method for fabricating SU8 three dimensional (3D) prisms with very small inclined-angles for optical-fiber/planar-waveguide interconnection with low insertion-loss by combining self-filling, molding and nano-lithography processes on plane surface. The prisms possess ultra low 3D inclined angle of 0.6° and a small surface roughness of 3.5 nm. It is demonstrated that the transmission efficiency of SOI waveguides improved about 4.6 times at the presence of SU8 prisms with a coupling loss of 11 dB per taper and radiation loss of 2.4 dB per taper.[[fileno]]2030180010026[[department]]電機工程學
Monolithic integration of two-dimensional transverse multimode interference couplers and silicon photonic wires
No full text[[abstract]]A new technology using hydrogen annealing and thermal oxidation is proposed to fabricate a very compact 2-D multimode interference coupler monolithically integrated with two-layer silicon photonic wires. Two devices, a 1 × 1 cross-power coupler and a 1 × 22 power splitter, are presented and characterized. The experimental result shows that a 3-dB transmission bandwidth of 1.1 nm, and the on-chip coupler losses of 8.6 dB and 2.84 dB were accomplished for the 1 × 1 cross-power coupler and the 1 × 22 power splitter. This paper demonstrates the possibility of realizing 3-D photonic integration for silicon-on-insulator lightwave circuits.[[fileno]]2030180010027[[department]]電機工程學
A novel multifunctional nano-platform with enhanced anti-cancer and photoacoustic imaging modalities using gold-nanorod-filled silica nanobeads
Get PDF[[abstract]]The novel nano-seaurchin structure is characteristic of high-density and well-dispersed gold nanorods in one mesoporous silica nanobead. This nanoplatform provided increased photothermal stability, stable photoacoustic signal and highly efficient hyperthermia effect both in vitro and in vivo, indicating a powerful theranostic modality.[[fileno]]2030143010032[[department]]電機工程學