Efficient AC-DC-AC converter for operation of variable speed small scale hydro power generation schemes

Abstract

In order to fulfill the ever increasing energy demands throughout the world, effort is being made to harness all possible energy sources. The dispersed energy sources such as wind and small hydro are no exception and they are being actively investigated for both technological feasibility and economic viability. In this paper, a fuzzy based PI controlled active front end AC-DC-AC converter is proposed to be employed for effective operation of a variable speed small scale hydro power generation scheme. With the help of the proposed controller it is possible to achieve a regulated voltage and frequency at the output terminal of the machine while the input power is variable as the water flow is not controlled. The system is observed to eliminate the complexity of civil works in tapping hydro potential thereby making the system more economical. A capacitor excited asynchronous generator (CAG) is considered for carrying out the studies owing to its numerous advantages such as easy availability, low cost, low maintenance and rugged construction of such machines. The merits of using active front end AC-DC-AC converter for small scale hydel power generation are clearly brought out and presented. The performance of the proposed system with both linear and nonlinear loads and the associated power quality issues and their remedies are detailed. A comparison of the performances of the proposed scheme with a conventional PI controller based system is also presented. The complete model of the proposed system is carried out in MATLAB/SIMULINK environment.