Passive automatic maximum wind energy tracking wind power generation system
This paper proposes a novel off-grid wind power generation system, comprising a double-winding permanent magnet synchronous generator, a three-phase controllable saturated reactor, two rectifiers, a battery and a load. The output power curve of the new system keeps in accordance with the maximum output power curve of the wind turbine, which makes the system track maximum wind energy automatically. A 300W prototype was manufactured. Experimental results show that the power output curve of the new system matches with the maximum output power curve of the wind turbine in a wide range of rotational speed. Compared with the traditional system, Wind energy utilization coefficient of the new system is improved greatly.
Modeling of a Converter-Connected Six-Phase Permanent Magnet Synchronous Generator
A MATLAB/Simulink model of a six-phase permanent magnet synchronous generator is established for simulation purpose. The machine is part of a microturbine generation system and is to be connected with a rectifier and a grid-connected inverter. It has two sets of three-phase windings on the stator side, which are shifted by 30 electrical degrees with each other. The internal dynamics of the machine is derived in a stationary d-q frame and then realized in MATLAB/Simulink with a user-definable S-function. The electrical interface with the converter is realized with a combination of voltage measuring units and controlled current sources provided by Simulink itself.
Mathematical Time and Physical Time in the Theory Of Relativity
In the Theory of Relativity time is an imaginary quantity that can not be observed; it is a multiplication of a number that indicates duration of material change and number i that is an imaginary number. i on the square is -1. Time i⁄t is a mathematical time that describes the speed and the duration of material change. In the Universe one can observe physical time only as a stream of material change. It is not that change run in physical time, change itself is physical time.. Distinction between imaginary mathematical time and visible physical time opens some new perspectives into interpretation of Theory of Relativity. c