Critical review of converter topologies for switched reluctance motor drives

This paper represents an overall literature review of SRM convenient drive circuit topologies with the proposal of a new topology utilizing switched capacitance circuit. The known topologies of SRM drive circuits were critically reviewed and compared. The main configurations and classifications of SRM and the principle of switched capacitance circuit with double capacitors, double switches are reviewed as well

A new converter topology for high-speed high-starting-torque three-phase switched reluctance motor drive system

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Switched reluctance motor (SRM) has become a competitive selection for many applications of electric machine drive systems recently due to its relative simple construction and its robustness. The advantages of those motors are high reliability, easy maintenance and good performance. The absence of permanent magnets and windings in rotor gives possibility to achieve very high speeds (over 10000 rpm) and turned SRM into perfect solution for operation in hard conditions like presence of vibrations or impacts. Such simple mechanical structure greatly reduces its price. Due to these features, SRM drives are used more and more into aerospace, automotive and home applications. The major drawbacks of the SRM are the complicated algorithm to control it due to the high degree of nonlinearity, also the SRM has always to be electronically commutated and the need of a shaft position sensor to detect the shaft position, the other limitations are strong torque ripple and acoustic noise effects

Possibility of information encoding/decoding using the memory effect in fractional-order capacitive devices

In this study, we show that the discharge voltage pattern of a supercapacitor exhibiting fractional-order behavior from the same initial steady-state voltage into a constant resistor is dependent on the past charging voltage profile. The charging voltage was designed to follow a power-law function, i.e. [Formula: see text], in which [Formula: see text] (charging time duration between zero voltage to the terminal voltage [Formula: see text]) and p ([Formula: see text]) act as two variable parameters. We used this history-dependence of the dynamic behavior of the device to uniquely retrieve information pre-coded in the charging waveform pattern. Furthermore, we provide an analytical model based on fractional calculus that explains phenomenologically the information storage mechanism. The use of this intrinsic material memory effect may lead to new types of methods for information storage and retrieval

Information Encoding/Decoding using the Memory Effect in Fractional-order Capacitive Devices

In this study, we show that the discharge voltage pattern of a fractional-order supercapacitor from the same initial steady-state voltage into a constant resistor is dependent on the past charging voltage profile. The charging voltage was designed to follow a power-law function, i.e. $v_c(t)=V_{cc} \left( {t}/{t_{ss}}\right)^p \;(0<t \leqslant t_{ss})$, in which $t_{ss}$ (charging time duration between zero voltage to the terminal voltage $V_{cc}$) and $p$ ($0<p<1$) act as two variable parameters. We used this history-dependence of the dynamic behavior of the device to uniquely retrieve information pre-coded in the charging waveform pattern. Furthermore, we provide an analytical model based on fractional calculus that explains phenomenologically the information storage mechanism. The use of this intrinsic material memory effect may lead to new types of methods for information storage and retrieval.Comment: 5 pages, 3 figures, Submitted on Jan 28, 2021 to ACS Applied Electronic Materials - Manuscript ID: el-2021-00092

Improved implementation of Chua's chaotic oscillator using current feedback op amp

An improved implementation of Chua's chaotic oscillator is proposed. The new realization combines attractive features of the current feedback op amp (CFOA) operating in both voltage and current modes to construct the active three-segment voltage-controlled nonlinear resistor. Several enhancements are achieved: the component count is reduced and the chaotic spectrum is extended to higher frequencies. In addition, a buffered and isolated voltage output directly representing a state variable is made available. Based on a linearized model of Chua's circuit, the useful tuning range of the major bifurcation parameter (G) and the expected frequency of oscillation, are estimate

A semi-systematic procedure for producing chaos from sinusoidal oscillators using diode-inductor and FET-capacitor composites

A design procedure for producing chaos is proposed. The procedure aims to transfer design issues of analog autonomous chaotic oscillators from the nonlinear domain back to the much simpler linear domain by intentionally modifying sinusoidal oscillator circuits in a semisystematic manner. Design rules that simplify this procedure are developed and then two composite devices, namely, a diode-inductor composite and a FET-capacitor composite are suggested for carrying out the modification procedure. Applications to the classical Wien-bridge oscillator are demonstrated. Experimental results, PSpice simulations, and numerical simulations of the derived models are include

Construction of classes of circuit-independent chaotic oscillators using passive-only nonlinear devices

Two generic classes of chaotic oscillators comprising four different configurations are constructed. The proposed structures are based on the simplest possible abstract models of generic second-order RC sinusoidal oscillators that satisfy the basic condition for oscillation and the frequency of oscillation formulas. By linking these sinusoidal oscillator engines to simple passive first-order or second-order nonlinear composites, chaos is generated and the evolution of the two-dimensional sinusoidal oscillator dynamics into a higher dimensional state space is clearly recognized. We further discuss three architectures into which autonomous chaotic oscillators can be decomposed. Based on one of these architectures we classify a large number of the available chaotic oscillators and propose a novel reconstruction of the classical Chua's circuit. The well-known Lorenz system of equations is also studied and a simplified model with equivalent dynamics, but containing no multipliers, is introduce

Construction of classes of circuit-independent chaotic oscillatorsusing passive-only nonlinear devices

Two generic classes of chaotic oscillators comprising four different configurations are constructed. The proposed structures are based on the simplest possible abstract models of generic second-order RC sinusoidal oscillators that satisfy the basic condition for oscillation and the frequency of oscillation formulas. By linking these sinusoidal oscillator engines to simple passive first-order or second-order nonlinear composites, chaos is generated and the evolution of the two-dimensional sinusoidal oscillator dynamics into a higher dimensional state space is clearly recognized. We further discuss three architectures into which autonomous chaotic oscillators can be decomposed. Based on one of these architectures we classify a large number of the available chaotic oscillators and propose a novel reconstruction of the classical Chua’s circuit. The well-known Lorenz system of equations is also studied and a simplified model with equivalent dynamics, but containing no multipliers, is introduced

Rational Best-Value Model based on Expected Performance

The best-value procurement strategy is gaining the interest of federal and state agencies. The strategy increases the value added to a project for each dollar added. A new concept of best value, that is, a rational and flexible model based on expected performance, is presented. The model\u27s flexibility is obvious in the selection of parameters to be included in the contractor selection process and in the determination of their weights. The model\u27s rationality will be achieved through relating all awarded scores to the agency\u27s expected performance. The establishment of the best-value model relies on the past record of the contractor\u27s work for the agency as an indicator of qualification trend. This research incorporates prequalification as a first-level screening technique in selecting top contractor bids in the best-value procurement and then applies a rational scoring system in the final selection. Selection of the most appropriate contractor with the best qualifications for a given project will be based on contractor best value. Data are collected from groups of experts in the Minnesota Department of Transportation and processed through the analytic hierarchy process to establish the parameter weights. Although this research assists departments of transportation in selecting the best contractor, the results are relevant to both academics and practitioners. The paper provides practitioners with a tool for ranking contractors based on best value and provides academics with selection parameters, a model to evaluate the best value, and a methodology for quantifying the qualitative effect of subjective factors