Abstract: Regarding PMSG-based wind turbine generation system, this paper proposes a supercapacitor energy storage unit (SCESU) which is connected in parallel with the DC-link of the back-to-back converter to enhance its high voltage ride through performance. The analysis of the operation and control for the grid-side converter and SCESU are conducted. Based on real time digital simulators (RTDS), a model and a Hardware-in-the-Loop (HiL) platform of PMSG-based wind turbine with SCESU is developed, and the simulation results show that the SCESU absorbs the imbalanced energy and the grid-side converter absorbs inductive reactive power during the period of voltage swell and verify the correctness and feasibility of the high voltage ride through control strategy. PubDate: Thu, 02 May 2019 00:00:00 +000
Abstract: A novel LTCC substrate manufacturing process based on 3D printing was investigated in this paper. Borosilicate glass-alumina substrates with controlled size and thickness were successfully manufactured using a self-developed dual-nozzle hybrid printing system. The printing parameters were carefully analyzed. The mechanical and dielectric properties of the printed substrate were examined. The results show that the printed substrates obtain smooth surface (Ra=0.92 μm), compact microstructure (relative density 93.7%), proper bending strength (156 mPa), and low dielectric constant and loss (Ɛr=6.2, =0.0055, at 3 GHz). All of those qualify the printed glass–ceramic substrates to be used as potential LTCC substrates in the microwave applications. The proposed method could simplify the traditional LTCC technology. PubDate: Mon, 01 Apr 2019 09:05:47 +000
Abstract: A quasi-two-dimensional physics-based model of HEMT transistor without using any smoothing functions for joining the linear and saturation regions of current-voltage (I-V) characteristics was developed. Considering the intervalley transitions of electrons and the presence of holes in the channel of transistor, we calculated the nonuniform spatial distributions of the electrical field, electron temperature, and electron mobility within the channel. The model is in a good agreement with experimental data over the linear and saturation regions of operation. The model provides precise simulating of HEMT transistors and can be utilized as a tool for analysis and prediction of influence of the material parameters on device and circuit characteristics. PubDate: Mon, 01 Apr 2019 08:05:33 +000
Abstract: A new concept of differential effective mobility is proposed. It characterizes the effective mobility of an increment of drain current resulting from a small increase of inversion charge in MOSFET channel. It allows us to show that the effective mobility can be described by a local electric field approach and not entirely by an effective electric field model. PubDate: Tue, 05 Mar 2019 16:05:01 +000
Abstract: This study proposed the designs of two full-phase operation transresistance-mode (TRM) precision full-wave rectifiers. The first circuit consisted of a single operational transresistance amplifier (OTRA), four diodes, and a resistor. The second scheme was an OTRA combined with a full metal-oxide semiconductor field-effect transistor-based design, which is preferable for integrated circuit implementation because no passive components are used in the circuit topology. Based on our literature review, this is the first study that discussed a full-phase operation transresistance-mode precision full-wave rectifier consisting of a single OTRA and few passive components. In this paper, several previously reported precision full-wave rectifiers consisting of various active devices are first reviewed followed by the proposed OTRA-based transresistance-mode precision full-wave rectifiers and an analysis of nonideal effects. Furthermore, computer simulations and experimental results are presented to verify the validity of the proposed circuits, which were consistent with the theoretical predictions. PubDate: Sun, 03 Mar 2019 10:05:19 +000
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