The Distributed Electronic Load Controller: A New Concept for Voltage Regulation in Microhydro Systems with Transfer of Excess Power to Households

Abstract Constant voltage and frequency can be generated by a stand-alone Self-Excited Induction Generator (SEIG) driven with a fixed-speed low-head hydro-turbine when the electrical load is maintained constant by an Electronic Load Controller (ELC). In a Conventional-ELC (C-ELC), usually a chopper with a dump load is used in parallel with the consumer loads to provide regulation of voltage and control of frequency. However, in the C-ELC configuration excess generated power may be wasted in a dump load. The objective of this research is to design a simplified ELC for each household to transfer the excess power for domestic consumption in addition to providing voltage regulation. Hence, a new ELC topology is proposed. This topology can be split into two parts. The first part is a regular ELC of low rated power, which should be installed at the generator site and it is responsible for precise voltage and frequency regulation and dealing with unexpected failure conditions. The second one is a simplified and inexpensive ELC which is installed in each household to direct excess power to a low wattage household apparatus in addition to participation in voltage regulation by maintaining constancy of the load power. This concept is referred to here as the Distributed ELC (DELC). One significant advantage of the proposed DELC approach is that the excess power can be utilized for domestic hot water purposes, and possibly resulting in health benefits related to improved sanitation. Moreover, the proposed topology shows more reliability compared with the C-ELC. Simulation results demonstrate that even with unbalanced three-phase loads (assisted with bi-directional switches per-phase), the proposed topology has the capability to regulate voltage from no-load to full load. Moreover, in the case of a failure in the power switches or the control circuits, the DELC has more reliable performance than a C-ELC.