High-current adaptive impedance matching in narrowband power-line communication systems

This paper proposes a high current impedance matching method for narrowband power-line communication (NPLC) systems. The impedance of the power-line channel is time and location variant; therefore, coupling circuitry and the channel are not usually matched. This not only results in poor signal integrity at the receiving end, but also leads to a higher transmission power requirement to secure the communication process. To offset this negative effect, a high-current adaptive impedance circuit to enable impedance matching in power-line networks is reported. The approach taken is to match the channel impedance of N-PLC systems is based on the General Impedance Converter (GIC). In order to achieve high current a special coupler in which the inductive impedance can be altered by adjusting a microcontroller controlled digital resistor is demonstrated. It is shown that the coupler works well with heavy load current in power line networks. It works in both low and high transmitting current modes, a current as high as 760 mA has been obtained. Besides, compared with other adaptive impedance couplers, the advantages include higher matching resolution and a simple control interface. Experimental results are presented to demonstrate the operation of the coupler. © 2011 IEEE.

Transient thermal analysis of power devices based on Fourier-series thermal model

A new thermal model based on Fourier series expansion method has been presented for dynamic thermal analysis on power devices. The thermal model based on the Fourier series method has been programmed in MATLAB SIMULINK and integrated with a physics-based electrical model previously reported. The model was verified for accuracy using a two-dimensional Fourier model and a two-dimensional finite difference model for comparison. To validate this thermal model, experiments using a 600V 50A IGBT module switching an inductive load, has been completed under high frequency operation. The result of the thermal measurement shows an excellent match with the simulated temperature variations and temperature time-response within the power module. ©2008 IEEE.

Transient electrothermal simulation of power semiconductor devices

In this paper, a new thermal model based on the Fourier series solution of heat conduction equation has been introduced in detail. 1-D and 2-D Fourier series thermal models have been programmed in MATLAB/Simulink. Compared with the traditional finite-difference thermal model and equivalent RC thermal network, the new thermal model can provide high simulation speed with high accuracy, which has been proved to be more favorable in dynamic thermal characterization on power semiconductor switches. The complete electrothermal simulation models of insulated gate bipolar transistor (IGBT) and power diodes under inductive load switching condition have been successfully implemented in MATLAB/Simulink. The experimental results on IGBT and power diodes with clamped inductive load switching tests have verified the new electrothermal simulation model. The advantage of Fourier series thermal model over widely used equivalent RC thermal network in dynamic thermal characterization has also been validated by the measured junction temperature.© 2010 IEEE.

Characterization and control of a pneumatic microactuator with an integrated inductive position sensor

As the intelligence and the functionality of microrobots increase, there is a growing need to incorporate sensors into these robots. In order to limit the outer dimensions of these microsystems, this research investigates sensors that can be integrated efficiently into microactuators. Here, a pneumatic piston-cylinder microactuator with an integrated inductive position sensor was developed. The main advantage of pneumatic actuators is their high force and power density at microscale. The outside diameter of the actuator is 1.3 mm and the length is 15 mm. The stroke of the actuator is 12 mm, and the actuation force is 1 N at a supply pressure of 1.5 MPa. The position sensor consists of two coils wound around the cylinder of the actuator. The measurement principle is based on the change in coupling factor between the coils as the piston moves in the actuator. The sensor is extremely small since one layer of 25 μm copper wire is sufficient to achieve an accuracy of 10 μm over the total stroke. Position tests with a PI controller and a sliding mode controller showed that the actuator is able to position with an accuracy up to 30 μm. Such positioning systems offer great opportunities for all devices that need to control a large number of degrees of freedom in a restricted volume. © 2007 Elsevier B.V. All rights reserved.

Modeling bipolar power semiconductor devices gachovska

This book presents physics-based models of bipolar power semiconductor devices and their implementation in MATLAB and Simulink. The devices are subdivided into different regions, and the operation in each region, along with the interactions at the interfaces which are analyzed using basic semiconductor physics equations that govern their behavior. The Fourier series solution is used to solve the ambipolar diffusion equation in the lightly doped drift region of the devices. In addition to the external electrical characteristics, internal physical and electrical information, such as the junction voltages and the carrier distribution in different regions of the device, can be obtained using the models. Table of Contents: Introduction to Power Semiconductor Device Modeling/Physics of Power Semiconductor Devices/Modeling of a Power Diode and IGBT/IGBT Under an Inductive Load-Switching Condition in Simulink/Parameter Extraction. © 2013 by Morgan & Claypool.

Low power consumption and high sensitivity carbon monoxide gas sensor using indium oxide nanowire.

In this paper, micro gas sensor was fabricated using indium oxide nanowire for effective gas detection and monitoring system. Indium oxide nanowire was grown using thermal CVD, and their structural properties were examined by the SEM, XRD and TEM. The electric properties for microdropped indium oxide nanowire device were measured, and gas response characteristics were examined for CO gas. Sensors showed high sensitivity and stability for CO gas. And with below 20 mw power consumption, 5 ppm CO could be detected.