MPPT Based on Power Mapping and Frequency Derivative

This article presents a method for harmonic mitigation and maximum power point tracking for a variable-speed grid-connected  wind turbine. The wind energy conversion system consists of a permanent magnet synchronous generator driven by variable-speed wind turbine. The output of the permanent magnet synchronous generator is connected to a single-switch three-phase boost rectifier to generate DC voltage, which feeds a current-controlled inverter to interface the system with the electric utility. The single-switch three-phase boost rectifier is an active power factor correction technique to maintain the power factor at the permanent magnet synchronous generator side to nearly unity and mitigate the permanent magnet synchronous generator current harmonics. To mitigate inverter output current and voltage harmonics, an LCL filter has been used. Acomplete analysis of the harmonic content has been done everywhere in the system. The results show that the proposed maximum power point tracking control strategy succeeded to track the maximum wind power irrespective of the wind speed. This strategy in presence of an LCL filter achieved harmonic mitigation at the permanent magnet synchronous generator and inverter output sides. Keywords: variable-speed wind turbine ; permanent magnet synchronous generator ; maximum power point tracking ; harmonic mitigation ; active power filter.

An Investigation on the Techniques used in Force Calibration using Deadweights and Pressure Piston Gauge

This paper presents two mechanisms for load cell calibrations. The first technique was to use deadweight to generate the required reference load (Applied load). The second method was to use a pressure piston gauge to generate the required calibration force. In both mechanisms, the setup and procedures are described. For verification the results of these methods were compared with international metrology institute calibration results. It was found that deadweight method is the most accurate and the piston gauge is the most realistic at high force values

An Investigation on the Techniques used in Force Calibration using Deadweights and Pressure Piston Gauge

537-543This paper presents two mechanisms for load cell calibrations. The first technique was to use deadweight to generate the required reference load (Applied load). The second method was to use a pressure piston gauge to generate the required calibration force. In both mechanisms, the setup and procedures are described. For verification the results of these methods were compared with international metrology institute calibration results. It was found that deadweight method is the most accurate and the piston gauge is the most realistic at high force values

An investigation on using the falling mass technique for dynamic force calibrations

In this paper, we present an experimental setup developed for the calibration of dynamic force transducers which is based on the drop mass method. The traceability to SI units is realized through well-known mass characteristics and a reference shock accelerometer attached to that mass. Two approaches are proposed to analyse dynamic force employing a drop mass system. One approach depends on the inertial force of a falling mass while the other deals with the work-energy principle. Results of both approaches are then compared to the response of a statically calibrated force transducer. It is shown that the obtained maximum relative deviations between the response of force transducer and the first approach results are 1% while those of the second approach are 2%