Showing papers in "Canadian Electrical Engineering Journal in 1988"
TL;DR: In this article, the authors compared the results obtained from digital and hybrid simulation studies on a variable speed wind generator interconnected to the utility grid and concluded that the results demonstrate that the digital simulation reproduces the dynamic behaviour of the system in a satisfactory manner and thus constitutes a valid tool for the design of the control systems of the wind generator.
Abstract: Describes the comparative results obtained from digital and hybrid simulation studies on a variable speed wind generator interconnected to the utility grid. The wind generator is a vertical-axis Darrieus type coupled to a synchronous machine by a gear-box; the synchronous machine is connected to the AC utility grid through a static frequency converter. Digital simulation results have been obtained using CSMP software; these results are compared with those obtained from a real-time hybrid simulator that in turn uses a part of the IREQ HVDC simulator. The agreement between hybrid and digital simulation results is generally good. The results demonstrate that the digital simulation reproduces the dynamic behaviour of the system in a satisfactory manner and thus constitutes a valid tool for the design of the control systems of the wind generator.
4 citations
TL;DR: A proposed structure for the realization of an iterative threshold selection algorithm is presented and it is shown that threshold selection algorithms play an important role in digital image analysis.
Abstract: Since the advent of VLSI some attention has been given to the hardware implementation of algorithms In the area of digital image analysis, threshold selection algorithms play an important role In this paper a proposed structure for the realization of an iterative threshold selection algorithm is presented
4 citations
TL;DR: In this paper, a real-time signal processing and cross correlation of two data streams is described, which is used to distinguish between near and far-side corrosion pit signals obtained by magnetic flux leakage detectors used in pipeline inspection.
Abstract: A demonstration of online real-time signal processing and cross correlation of two data streams is described. The demonstration is used to distinguish between near and far-side corrosion pit signals obtained by magnetic flux leakage detectors used in pipeline inspection. A PC-based data acquisition system is used, and an algorithm employing five simple processing stages is described. The demonstration reveals that processing speed is not a problem, however, if used as an operational tool, power requirements are likely to be a challenge.
2 citations
IBM1
TL;DR: In this article, an approximate minimum variance estimator algorithm that recursively updates the state estimate and its error covariance and closely approximates the exact minimax estimator is derived.
Abstract: Considers the problem of sequential state estimation of discrete-time processes based on quantized measurements. An approximate minimum variance estimator algorithm that recursively updates the state estimate and its error covariance and closely approximates the exact minimum variance estimator is derived. The results of Monte-Carlo simulation are presented and the performance of the algorithm is compared to that of a Kalman filter in which the quantization error is approximated by an additive white Gaussian measurement noise.
2 citations
TL;DR: In this paper, a generalized loss formula (GLF) is developed for the system losses around an operating point, which is a quasi-oscillatory approximation of the exact losses by having the same first and approximately the same second derivatives at the operating point.
Abstract: A generalized loss formula (GLF) is developed for the system losses around an operating point. It is a quasi-oscillatory approximation of the exact losses by having the same first and approximately the same second derivatives at the operating point, with respect to three sets of variables: generator powers Pg, generator voltage magnitudes Vg, and transformer tap settings t. The numerical results obtained from two test systems demonstrate that the error in the losses given by the GLF, in comparison to the exact losses from a load flow calculation, is relatively small.
TL;DR: In this paper, two identical three-stage GaAsFET amplifiers were built which give excess noise temperatures of less than 28 K with at least 34 dB gain between 1.35 and 1.75 GHz when operated at a physical temperature of 12 K.
Abstract: A low-noise receiver for a radio telescope is described. Two identical three-stage GaAsFET amplifiers were built which give excess noise temperatures of less than 28 K with at least 34 dB gain between 1.35 and 1.75 GHz when operated at a physical temperature of 12 K. This noise temperature is measured at the cryostat input connectors. The physical temperature is maintained by a closed cycle helium refrigerator. Source-inductance feedback is used to allow optimum noise performance combined with good input match. Return loss is better than 15 dB across the band. Construction details of the amplifiers and their mounting in the cryostat are provided. Sample observational results are presented.
TL;DR: In this paper, the authors proposed a study on the analysis of the operation of a single-phase PWM (pulse width modulation) inverter structure taking into account non-linearities such as an impedant supply or nonlinear loads (triacs, rectifiers).
Abstract: The authors propose a study on the analysis of the operation of a single-phase PWM (pulse width modulation) inverter structure-taking into account non-linearities such as an impedant supply or nonlinear loads (triacs, rectifiers). They analyze the control action in order to optimize the load voltage harmonic spectrum. Two principal considerations for the study are first, to avoid unduly increasing the switching frequency, and second, to optimize the power to weight ratio of the converter. Numerical simulations and experimental results are obtained to validate the proposed method.