Optimization techniques for p-GTO thyristor design

A new type of semiconductor power device was devised in the early ’90s as an alternative to the classic Gate Turn-Off (GTO) thyristor. Because the low-doped n-base was replaced by a low-doped p-base, it was called the p-GTO. Its main advantage is a higher possible control voltage when the device is switched off, leading to the possibility of a higher blocking anode current (IATO) and a lower turn-off time. The studies and techniques employed with the help of SILVACO-TCAD simulation software Athena and Atlas show that the p-GTO has higher breakdown voltages compared with its classic counterpart and similar on-state voltage (VT) and switching characteristics when replacing the GTO in the same circuit. Specific circuit improvements, like an affordable higher turn-off gate voltage, will drive the p-GTO into even faster switching operation.

Design Simulation of Improved Power Quality Conditioner System for Enhancement of Power Quality

The increased usage of power-sensitive electronic devices has prompted interest in power conditioning solutions, which is no surprise. As a result, some type of compensation must be supplied if power output remains below the standards' prescribed limitations. The UPQC (Unified Power Quality Controller) is one of numerous AC Transmission System families that can control voltage, impedance, and phase angle among other factors (FACTS). This study focuses on modern UPFC systems that have increased power quality efficiency to help utilities reduce voltage concerns. One of the FACTS controls for lowering stress sales effects is a unified power quality conditioner (UPQC). The quadrature voltage is specified using the UPQC series compensator. As a result, the compensator series never utilizes active power in a continuous scenario. As mentioned in the approach, a low power rating compensator injects voltage to remedy the system's power quality problem. The voltage is decreased and the power factor is raised when the fluid logic controller is used in conjunction with traditional UPQC. Furthermore, the load factor has been improved. The circuit is then imitated in MATLAB / SIMULINK using a fluctuating logo controller.

First SIMO Harmonic Radar Based on the SFCW Concept and the HR Transfer Function

This paper presents a new SIMO radar system based on a harmonic radar (HR) stepped frequency continuous wave (SFCW) architecture. Simple tags that can be electronically individually activated and deactivated via a DC control voltage were developed and combined to form an MO array field. This HR operates in the entire 2.45 GHz ISM band for transmitting the illumination signal and receives at twice the stimulus frequency and bandwidth centered around 4.9 GHz. This paper presents the development, the basic theory of a HR system for the characterization of objects placed into the propagation path in-between the radar and the reflectors (similar to a free-space measurement with a network analyzer) as well as first measurements performed by the system. Further detailed measurement series will be made available later on to other researchers to develop AI and machine learning based signal processing routines or synthetic aperture radar algorithms for imaging, object recognition, and feature extraction. For this purpose, the necessary information is published in this paper. It is explained in detail why this SIMO-HR can be an attractive solution augmenting or replacing existing systems for radar measurements in production technology for material under test measurements and as a simplified MIMO system. The novel HR transfer function, which is a basis for researchers and developers for material characterization or imaging algorithms, is introduced and metrologically verified in a well traceable coaxial setup.

A Linear VCO Using Single CFA and Analog Multipliers: Quadrature Oscillator Implementation

A new linear voltage-controlled oscillator (LVCO) implementation using single AD-844 CFA with a pair of AD-835 multiplier devices and a pair of grounded capacitors is proposed. The open-loop transfer function of the topology is analyzed wherein the concept of Short-Circuit Natural Frequency (SCNF) is applied to derive the sinusoid oscillator implementation. The proposed oscillator circuit is then restructured to yield a linear voltage-controlled quadrature oscillator (LVCQO) after appropriate cascade with a CFA-based active integrator. The oscillation frequency is linearly tunable ([Formula: see text][Formula: see text]MHz) by the multiplier control voltage ([Formula: see text]. Subsequently, a high-[Formula: see text] selective band-pass (BP) filter is derived. Effects of the CFA port roll-off parameters and its parasitic capacitors ([Formula: see text] had been analyzed to be negligible. Measured oscillator response exhibited a THD [Formula: see text]%, a linearity error ([Formula: see text]% and a phase noise figure of ([Formula: see text]104 dBc/Hz at 24-kHz offset.

A field-oriented control (FOC) method using the virtual currents for the induction motor drive

<span lang="EN-US">An improving field-oriented control technique without current sensors is proposed to control rotor speed for an induction motor drive. The estimated stator currents based on the slip frequency are used instead of feedback current signals in the FOC loop. The reference signals and the estimated currents through computation steps are used to generate the control voltage for the switching inverter. Simulations were performed in Matlab/Simulink environment at rated speed and low-speed range to demonstrate the method's feasibility. Through simulation results, the FOC method using virtual sensors has proved its effectiveness in ensuring the stable operation of the IMD over a wide speed range.</span>

High-performance 1×4 - demultiplexer for next-generation all-optical telecommunication systems

In this paper the new 1×4 optical demultiplexer for next-generation all-optical switching systems is proposed. The controlled mirrors are the main elements of this device. The control voltage for this mirror is generated by a rectenna from an optical control signal. In according to operation principle this optical signal enters the system simultaneously with an information signal. The analytical approach of calculation energy losses in the demultiplexer based on the translation matrix method is proposed. And also the analytical method of performance calculation is offered for the first time. First of all, the delay time due the transient mode in the power supply circuit is found. The equivalent electrical scheme of the optical demultiplexer is proposed for the first time. Note that the theoretical results obtained in this work can be used for analysing various controlled optical devices. The numerical calculations in accordance to the presented methods are carried out also.

A Novel Approach for the Design of Fast-Settling Amplifiers for Biosignal Detection

The most common method used to pick up biomedical signals is through metallic electrodes coupled to the input of high-gain, low-noise amplifiers. Unfortunately, electrodes, amongst other effects, introduce an undesired contact resistance and a contact potential. The contact potential needs to be rejected since it would otherwise cause the saturation of the input stage of the amplifiers, and this is almost always obtained by inserting a simple RC high-pass filter in the input signal path. The contact resistance needs to be estimated to ensure that it does not impair correct measurements. Methods exist for estimating the contact resistance by dynamically modifying the input network configuration, but because of the presence of the input RC filter, long transients are induced any time a switch occurs between different input configurations, so that the measurement time may become unacceptably long. In this paper, we propose a new topology for a DC removal network at the input of the differential signal amplifier that results in an AC filter whose time constant can be continuously changed by means of a control voltage. As such, we can speed up the recovery from transients by setting very short time constants (during the input resistance estimation process) while maintaining the ability to obtain very low cut-in frequencies by setting a much larger time constant during actual measurements. A prototype of the system was built and tested in order to demonstrate the advantage of the approach we propose in terms of reduced measurement time.

Intelligent Matching of the Control Voltage of Delay Line Interferometers for Differential Phase Shift Keying-Modulated Optical Signals

In optical communications, differential phase shift keying (DPSK) provides a desired modulation format that offers high tolerance to nonlinear effects in high-speed transmissions. A DPSK demodulator converts the phase-coded signal into an intensity-coded signal at receivers. One demodulation scheme is called balanced detection and is based on a tunable delay line interferometer (DLI). Demodulation performances are determined by the phase delay generated by the DLI, while the phase delay is controlled by a tunable driving voltage on the DLI device. However, a problem in the dynamic adjustment of the control voltage prevents the application of DPSK demodulators. The receivers need to scan the whole control voltage range of the DLI and find the control voltage that maximizes the demodulation performance, but the scan-based method needs to undergo a very long searching time. In our work, we found that the relation between DLI control voltages and demodulation performance can be predicted rapidly by a feedforward neural network (FNN). In this paper, we propose a new method to quickly locate the best DLI control voltage based on an FNN. We also verify the proposed method in simulations and telecommunication systems, and the results show that the proposed method can significantly improve the efficiency of resolving the best demodulation voltages.

Modulation Linearization Technique for FM/CW SAR Image Processing Using Range Migration

Linear FMCW radar suffers from impairments in range and range rate if there are errors in the modulation rate or phase discontinuities. Often, this is a result of a nonlinearity of the voltage-controlled oscillator that is in the source of the transmit and receive local oscillator. The nonlinearity can be corrected at the source by using a nonlinear control voltage or by processing the received beat frequency. Any signal processing using the later method leads to computation time and energy costs, which can be considerable in some applications. When the range migration algorithm using the Stolt Transform is used for Synthetic Aperture Radar (SAR) image processing, the autofocus linearization technique described here costs nothing in additional hardware or computation time.