Active filtering of electric power has now become a mature technology for harmonic and reactive power compensation in two-wire (single phase), three-wire (three phase without neutral), and four-wire (three phase with neutral) AC power networks with nonlinear loads. This paper presents a comprehensive review of active filter (AF) configurations, control strategies, selection of components, other related economic and technical considerations, and their selection for specific applications. It is aimed at providing a broad perspective on the status of AF technology to researchers and application engineers dealing with power quality issues. A list of more than 200 research publications on the subject is also appended for a quick reference.

A review of active filters for power quality improvement

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

This paper presents an optimal power management mechanism for grid connected photovoltaic (PV) systems with storage. The objective is to help intensive penetration of PV production into the grid by proposing peak shaving service at the lowest cost. The structure of a power supervisor based on an optimal predictive power scheduling algorithm is proposed. Optimization is performed using Dynamic Programming and is compared with a simple ruled-based management. The particularity of this study remains first in the consideration of batteries ageing into the optimization process and second in the “day-ahead” approach of power management. Simulations and real conditions application are carried out over one exemplary day. In simulation, it points out that peak shaving is realized with the minimal cost, but especially that power fluctuations on the grid are reduced which matches with the initial objective of helping PV penetration into the grid. In real conditions, efficiency of the predictive schedule depends on accuracy of the forecasts, which leads to future works about optimal reactive power management.

Optimal Power Flow Management for Grid Connected PV Systems With Batteries

With the fast-paced changing technologies in the power industry, new power references addressing new technologies are coming to the market. So there is an urgent need to keep track of international experiences and activities taking place in the field of modern unit-commitment (UC) problem. This paper gives a bibliographical survey, mathematical formulations, and general backgrounds of research and developments in the field of UC problem for past 35 years based on more than 150 published articles. The collected literature has been divided into many sections, so that new researchers do not face any difficulty in carrying out research in the area of next-generation UC problem under both the regulated and deregulated power industry.

Unit commitment-a bibliographical survey

The hydrogen-fueled internal combustion engine : a technical review.

This paper describes how to extract the fundamental-frequency components from the voltage and current waveforms in a split-phase induction motors that is fed through a static voltage controller. These components are derived not from conducting a fast Fourier transform, but rather from few phase angles that are easily provided by zero-crossing and peak detectors. It is shown that knowledge of these components is useful when attempting to optimize load efficiency, and when assessing the power loss due to harmonic distortion. The analysis in this paper is partially validated by laboratory tests on a 1/3 hp split-phase motor.

Fundamental-frequency components in single-phase motors with SCR Voltage Controllers

This paper evaluates the power loss in fractional-horsepower split-phase motors when fed by an SCR-based voltage controller that is utilized to improve motor efficiency. In particular, the additional harmonic power loss due to waveform distortion is quantified in terms of the total power loss in the motor. The analysis shows that harmonic losses are primarily due to the third harmonic component. Laboratory measurements on a 1/3 hp motor indicate that harmonic losses represent as such as a quarter of the total loss under light load conditions.

Power loss in split-phase induction motors with SCR voltage controllers

A partial commissioning and energy audit were performed on a recently constructed building at the University of Nevada, Las Vegas (UNLV). Although the building is relatively new and has passed all building code requirements, it has not undergone a formal commissioning process to check that the mechanical systems, such as the heating, ventilation, and air conditioning (HVAC), were performing at optimally designed conditions. The building is approximately 35,000 ft2 spread over three floors. The following components and systems were inspected, tested, and/or analyzed during the project: rooftop units, ducting flow rates, VAV units, room supply air fl ows, thermostats, temperature control sensors, some preliminary aspects of IAQ, some aspects of lighting, hot water heating, occupancy and occupant perceptions, and operating parameters. The building chosen has an energy management system (EMS), and hence its data can be reasonably evaluated. In addition to the inspections of the above items in the abo...

Preliminary Commissioning and Energy Audit of a UNLV Building

This article evaluates the method of reducing power loss due to 3rd harmonic currents in a building that contains a significant level of electronic loads, by placing a passive filter in the neutral path. The initial power loss is obtained through current measurements in the phase and neutral conductors and knowledge of the resistance of these conductors and that of the transformer serving the facility. PSpice simulations are performed to determine the most suitable RL-C filter to minimize this loss. The losses are found to be not that significant due to existing reinforcements in the distribution circuit. The effect of filter placement on voltage distortion and capacitor resonance with the transformer leakage inductance are addressed.

Evaluation of harmonic current reduction for the purpose of energy savings — A case study

This paper investigates the effect of slot-harmonics on the DC-side voltage of a generator-rectifier set. The average voltage and ripple factor of the rectified waveform are derived in terms of the generator voltage harmonic magnitudes and their phase relation with respect to the fundamental component. The analysis is illustrated by a numerical example and a laboratory test on an actual auxiliary power unit of a hybrid-electric transit vehicle. It is found that while slot harmonics have a negligible impact on the average voltage, the increase in ripple factor can be significant.

Yahia Baghzouz

Papers

Fundamental-frequency components in single-phase motors with SCR Voltage Controllers

Power loss in split-phase induction motors with SCR voltage controllers

Preliminary Commissioning and Energy Audit of a UNLV Building

Evaluation of harmonic current reduction for the purpose of energy savings — A case study

Slot-harmonic effects on DC voltage of generator-rectifier set