Realization of transfer impedances using distributed RC elements in a common ground Linvill configuration

One of several synthesis procedures available for the realization of a transfer admittance is that of Linvill. This synthesis procedure employs an active element, a negative impedance converter (NIC), to shift the poles of passive immittance functions from the negative real axis into the complex plane to realize the desired transfer immittance function. The Linvill synthesis procedure is extended to networks containing cascaded distributed RC elements and the conditions which must be satisfied to realize a transfer impedance using these distributed elements are defined

Stability analysis of switched dc-dc boost converters for integrated circuits

Boost converters are very important circuits for modern devices, especially battery- operated integrated circuits. This type of converter allows for small voltages, such as those provided by a battery, to be converted into larger voltage more suitable for driving integrated circuits. Two regions of operation are explored known as Continuous Conduction Mode and Discontinuous Conduction Mode. Each region is analyzed in terms of DC and small-signal performance. Control issues with each are compared and various error amplifier architectures explored. A method to optimize these amplifier architectures is also explored by means of Genetic Algorithms and Particle Swarm Optimization. Finally, stability measurement techniques for boost converters are explored and compared in order to gauge the viability of each method. The Middlebrook Method for measuring stability and cross-correlation are explored here

Modeling and Analysis of Power Processing Systems (MAPPS). Volume 1: Technical report

Computer aided design and analysis techniques were applied to power processing equipment. Topics covered include: (1) discrete time domain analysis of switching regulators for performance analysis; (2) design optimization of power converters using augmented Lagrangian penalty function technique; (3) investigation of current-injected multiloop controlled switching regulators; and (4) application of optimization for Navy VSTOL energy power system. The generation of the mathematical models and the development and application of computer aided design techniques to solve the different mathematical models are discussed. Recommendations are made for future work that would enhance the application of the computer aided design techniques for power processing systems

System identification and adaptive current balancing ON/OFF control of DC-DC switch mode power converter

PhD ThesisReliability becomes more and more important in industrial application of Switch Mode Power Converters (SMPCs). A poorly performing power supply in a power system can influence its operation and potentially compromise the entire system performance in terms of efficiency. To maintain a high reliability, high performance SMPC effective control is necessary for regulating the output of the SMPC system. However, an uncertainty is a key factor in SMPC operation. For example, parameter variations can be caused by environmental effects such as temperature, pressure and humidity. Usually, fixed controllers cannot respond optimally and generate an effective signal to compensate the output error caused by time varying parameter changes. Therefore, the stability is potentially compromised in this case. To resolve this problem, increasing interest has been shown in employing online system identification techniques to estimate the parameter values in real time. Moreover, the control scheme applied after system identification is often called “adaptive control” due to the control signal selfadapting to the parameter variation by receiving the information from the system identification process. In system identification, the Recursive Least Square (RLS) algorithm has been widely used because it is well understood and easy to implement. However, despite the popularity of RLS, the high computational cost and slow convergence speed are the main restrictions for use in SMPC applications. For this reason, this research presents an alternative algorithm to RLS; Fast Affline Projection (FAP). Detailed mathematical analysis proves the superior computational efficiency of this algorithm. Moreover, simulation and experiment result verify this unique adaptive algorithm has improved performance in terms of computational cost and convergence speed compared with the conventional RLS methods. Finally, a novel adaptive control scheme is designed for optimal control of a DC-DC buck converter during transient periods. By applying the proposed adaptive algorithm, the control signal can be successfully employed to change the ON/OFF state of the power transistor in the DC-DC buck converter to improve the dynamic behaviour. Simulation and experiment result show the proposed adaptive control scheme significantly improves the transient response of the buck converter, particularly during an abrupt load change conditio

THE STUDY AND ANALYSIS OF MPPT CONTROLLER FOR SRBC

This work is about designing Maximum Power Point Tracker (MPPT) with Synchronous Rectifier Buck Converter (SRBC) circuit where the main purpose is to improve the performance and increase the output voltage and current. The MPPT controller controls the output current of the input (usually solar array) so that the output power converges on the maximum based on the linearity between the maximum output power and the optimal current. In this work, MPPT' s characteristics, performance, operation modes, advantages, and disadvantages are analyzed and observed. Then, combination ofMPPT and adaptive gate drive (AGD) will be applied to SRBC as the output circuit. PSPICE software is used in designing and simulating both circuits. The comparison is carried out based on the average output voltage and current, node voltage, output ripple voltage and current, gate-to-source voltage, and body diode conduction loss of the MPPT circuit and MPPT with AGD circuit. The details are discussed thoroughly that include limitations and advantages in the design of the controllers using I MHz switching frequency. It is found that by implementing MPPT controller with SRBC, the output voltage and output current have increased by approximately 12%- 13% for both CCM and DCM conditions. Besides that, it also reduces output voltage ripple and current around 70 % for CCM mode. However, in DCM condition, the output peak-to-peak ripple for both voltage and current have increased by 20 %

Laboratory modeling and analysis of aircraft-lightning interactions

Modeling studies of the interaction of a delta wing aircraft with direct lightning strikes were carried out using an approximate scale model of an F-106B. The model, which is three feet in length, is subjected to direct injection of fast current pulses supplied by wires, which simulate the lightning channel and are attached at various locations on the model. Measurements are made of the resulting transient electromagnetic fields using time derivative sensors. The sensor outputs are sampled and digitized by computer. The noise level is reduced by averaging the sensor output from ten input pulses at each sample time. Computer analysis of the measured fields includes Fourier transformation and the computation of transfer functions for the model. Prony analysis is also used to determine the natural frequencies of the model. Comparisons of model natural frequencies extracted by Prony analysis with those for in flight direct strike data usually show lower damping in the in flight case. This is indicative of either a lightning channel with a higher impedance than the wires on the model, only one attachment point, or short streamers instead of a long channel

New synthesis procedures for realizing transfer function of RLC and RC networks

"September 14, 1951." "This report is identical with a doctoral thesis in the Department of Electrical Engineering, Massachusetts Institute of Technology, 1951."Bibliography: p. 105.Army Signal Corps Contract no. DA36-039 sc-100 Project No. 8-102B-0. Dept. of the Army Project No. 3-99-10-022.Louis Weinberg

Ultra-Low Power Transmitter and Power Management for Internet-of-Things Devices

Two of the most critical components in an Internet-of-Things (IoT) sensing and transmitting node are the power management unit (PMU) and the wireless transmitter (Tx). The desire for longer intervals between battery replacements or a completely self-contained, battery-less operation via energy harvesting transducers and circuits in IoT nodes demands highly efficient integrated circuits. This dissertation addresses the challenge of designing and implementing power management and Tx circuits with ultra-low power consumption to enable such efficient operation. The first part of the dissertation focuses on the study and design of power management circuits for IoT nodes. This opening portion elaborates on two different areas of the power management field: Firstly, a low-complexity, SPICE-based model for general low dropout (LDO) regulators is demonstrated. The model aims to reduce the stress and computation times in the final stages of simulation and verification of Systems-on-Chip (SoC), including IoT nodes, that employ large numbers of LDOs. Secondly, the implementation of an efficient PMU for an energy harvesting system based on a thermoelectric generator transducer is discussed. The PMU includes a first-in-its-class LDO with programmable supply noise rejection for localized improvement in the suppression. The second part of the dissertation addresses the challenge of designing an ultra- low power wireless FSK Tx in the 900 MHz ISM band. To reduce the power consumption and boost the Tx energy efficiency, a novel delay cell exploiting current reuse is used in a ring-oscillator employed as the local oscillator generator scheme. In combination with an edge-combiner PA, the Tx showed a measured energy efficiency of 0.2 nJ/bit and a normalized energy efficiency of 3.1 nJ/(bit∙mW) when operating at output power levels up to -10 dBm and data rates of 3 Mbps. To close this dissertation, the implementation of a supply-noise tolerant BiCMOS ring-oscillator is discussed. The combination of a passive, high-pass feedforward path from the supply to critical nodes in the selected delay cell and a low cost LDO allow the oscillator to exhibit power supply noise rejection levels better than –33 dB in experimental results

Improvement of resonant harmonic filter effectiveness in the presence of distribution voltage distortion

Resonant harmonic filters (RHFs), are the most common devices installed in distribution systems for reducing distortion caused by harmonic generating loads. When such filters are applied in systems with a distorted distribution voltage their effectiveness may decline drastically. This dissertation explores the causes of degradation of RHFs effectiveness and suggests methods of their improvement both by optimization algorithms and by modification of the filter structure. An optimization based design method is developed for the conventional RHF. It takes into consideration the interaction of the filter with the distribution system and provides a filter which gives the maximum effectiveness with respect to harmonic suppression. The results for the optimized filters, applied in some typical cases, are given, and the limits of effectiveness for a common application are explored. For cases where the conventional RHF cannot be applied due to low effectiveness, a resonant harmonic suppressor, referred to as a RHF with line inductor, is investigated. It is formed by the addition of a line inductor to a conventional RHF, and it has a higher effectiveness in the presence distribution voltage distortion. A similar method of optimization based design is developed and evaluated for the RHF with line inductor as for the conventional RHF. Also, the limits of its effectiveness are explored. One major disadvantage of the RHF with line inductor is the load voltage reduction due to the additional impedance between the distribution system and load. For loads with variable reactive power, the voltage drop across the line inductor may reach an unacceptable level. Also, the fluctuation of the load voltage could increase. In order to reduce these effects, an adaptive capability with respect to load reactive power compensation is added to the filter. Such a filter, referred to as a semi-adaptive RHF, is obtained when a RHF is combined with a thyristor switched inductor (TSI). The addition of the TSI also increases flexibility in the design of the filter with respect to the line inductor’s value. Design aspects of the semi-adaptive RHF are explored and simulation results are presented