Energy conversion in small water plants with variable speed PM generator

Abstract

Energy conversion in small water plants with variable speed PM generatorThe Small Hydro Power Plants allow to increase the energy amount from renewable sources, especially from small rivers in mountainous areas. This paper presents a new concept of a energy conversion system for application in a Small Hydropower Plant (SHP) which is based on a permanent magnet generator (PM generator) with a propeller turbine integrated with the generator rotor. The PM generator can work at a variable speed and therefore energy produced by the PM generator has to be converted by means of a power electronic unit to fit to the three-phase power grid parameters. For this concept, dimensions and parameters of the PM generator were specially designed on account of integration with water turbine. The paper precisely describes elements of energy conversion system and also presents the results of numerical tests for chosen working conditions. An original algorithm of control strategy for power electronic unit was used to adjust generated energy to the required parameters of the three-phase grid.

Multi‐objective optimisation of hydroelectric PMSG considering water‐level variation

“…The PMSG often works at a variable speed and, therefore, energy produced by the PM generator is converted by means of a back‐to‐back pulse‐width modulation (PWM) converter to fit to the three‐phase power grid demands [17]. For this concept, dimensions and parameters of the PM generator were specially designed on account of integration with water‐level conditions.…”

“…In general, researchers have been habitually optimised the PMSG at rated power and rotating with constant speed. However, for long term, the water‐level varies greatly with the seasonal changes [15–17]. Hence, the generator performances are highly influenced by the water‐level variation, the output power, voltage magnitude, and frequency of generator changes in a wide range with the different water‐level conditions (low, normal, high).…”

Assessment of electrical energy production in small hydropower plant with ultra-low head

“…While improved and more efficient types of electrical generators are being investigated [6], common types of generators with improved efficiency are introduced to the market. In the field of frequency converters new principles of control [7], along with new technologies of 4-quadrant operation are being presented. These offer a possibility of feeding the energy to grid with a power factor cosφ close to 1 and operation of the plant with better efficiency at lower loads.…”

A novel proposal of cooperation between a cage induction generator and the three-phase grid

“…The synchronous generators, especially generators excited by permanent magnets, are almost always connected to the three-phase grid via the back-to-back converters [2,4,9,[16][17][18][19][20]. These energy conversion systems can operate even at low wind or water stream speed.…”