Dariusz Borkowski

This paper presents the control and monitoring system of a small hydropower plant (SHP). The control rules of the parameters in that type of objects, their practical realization by a dedicated control system and exemplary operation were described. In the second part the way of algorithm implementation using a modern hardware was presented. The control algorithm implementation from the software point of view was also shown. The paper contains the measurements from the real control and monitoring system of SHP. This SHP contains two permanent magnet (PM) generators of 75 kW electrical power each, which can work at a variable speed.

An analysis of the energy conversion system which consists of a propeller water turbine, a permanent magnet synchronous generator and a power electronic converter is presented. The considered control strategy implements an optimizing technique that guarantees maximal average efficiency independently of hydrological condition changes through the constant search for optimal operation parameters. The water flow parameter, essential for objective function estimation, is eliminated by the dedicated control technique. The control method is implemented and tested in the model created in the Matlab/Simulink software. All characteristics and parameters were identified on a real small hydropower plant and on the special laboratory model.

This paper presents the rules of management of an energy conversion system in a small hydropower plant (SHP). The SHP contains two permanent magnet (PM) generators which can work at a variable speed. In the article the way of obtaining the optimal work characteristic curve is described. To achieve the best efficiency the special methodology of units cooperation is also presented. The theoretic analysis is algorithmizated, implemented and tested in the real object of 150 kW electrical power. The measurement results of this object are presented.

Full efficiency of energy conversion in small hydropower plants (SHP) can be achieved for power technology with generators working at a variable speed. This paper presents a concept of a energy conversion system dedicated for application in a prototype SHP which is based on a permanent magnet (PM) generators with a propeller turbine integrated with the generator rotors. These PM generators can work at a variable speed and therefore energy produced by the PM generators have to be converted by means of a power electronic unit to fit to the three-phase power grid parameters. The elements of such SHP like PM generator and power electronic unit are described in details.

Induction generators are widely used to generate electrical power in small hydraulic applications. The main disadvantage of stand- alone induction generators is the problem of regulating the voltage magnitude and voltage frequency under load variation. This paper investigates a three-phase self-excited induction generator (SEIG) operating under varying load, utilizing the water energy in a small reservoir hydropower plant. The generator excitation is provided by a three-phase capacitor bank and an inverter with Space Vector Pulse Width Modulation (SVPWM). Furthermore, the inverter with a battery controls the active power flow between the generator and the load in order to provide a constant frequency of voltage. The proposed control scheme consists of two PI controllers. The first controls the voltage magnitude by regulating the inverter reactive power, while the second one adjusts the guide vanes of the turbine according to the DC voltage of the battery. The proposed control system has been tested under load step changes. The simulation results of the system, obtained using the Matlab/Simulink software, have demonstrated good control performance.