Modelling of Small Hydro Power by using Direct Power Control method

This paper presents modeling and simulating of a variable speed hydro power plant in which voltage source converters are used. Dynamic modeling of DFIM in hydro power plant is described using voltage source converters based on direct power control and differential equations are presented as models and their spatial representation is developed. In configuration of the system, a 3-level voltage source converter is used for controlling and changing voltage and frequency. Output includes a constant voltage, thus process of changing speed with faster dynamic response results in faster frequency response compared to other control methods .Investigation of two control methods shows that despite advantages of DTC, it has some problems including relatively high torque and flux ripple and variable switching frequency. These problems are due to improper selection of voltage vector and using hysteresis loop. For modeling and simulation the Matlab software have been used.