Simplification of Voltage and Frequency Control of a Small-Scale Hydropower System

Pico-hydro power systems are stand-alone and generally built to generate electricity for off-grid rural communities. Yet, this system requires an advanced mechanism or system to control the variation of water flow rate due to seasonal changes and patterns of the user's load profile. These variations will result in inconsistent output voltage and frequency from the electrical generator. Different approaches have been proposed to tackle this issue by controlling the electrical power output and water flow rate via electronic load controller; dump loads; power converters; and mechanical regulation of turbine water flow rate. To harvest maximum output power and minimize the power wastage, and overall cost for a pico-hydropower system, a practical approach that eliminates the use of costly dump load and uses a variable frequency drive (VFD) inverter and the power transformer is proposed for the control of voltage and frequency.