An Investigation of Micro-Hydro Power Generator Characteristics

Research on the electrical characteristics of hydroelectric power systems has to the author’s knowledge, not received much attention. However, renewed interest in hydropower microgeneration has created a need to understand the underlying properties. This thesis presents a pioneering empirical investigation into the electrical characteristics of micro- hydro power generators (MHPGs). An ohmic characteristic behaviour in MHPGs with constant source impedance, even with varying water flow is demonstrated for the first time. Experimental results showed variable flow correlation between the MHPGs voltage and current at the maximum power point, which coincides with 50% Voc and 50% of Isc. A novel heuristic model for hydroelectric power generator is then derived and validated through MATLAB-Simulink simulation. In pursuit of MHPG maximum utilisation efficiency, a new Seesaw maximum power point tracking (MPPT) controller is presented. The simple but accurate analogue Seesaw MPPT, which incorporates feedforward control of the output voltage only in a current- mode operation, proved fast tracking control under rapidly varying operational conditions. Only one voltage sensor is required. The renewed application of the classical feedforward mechanism offers superior MPPT response (μ seconds). This approach is unlike previous work in that it uses the current-voltage characteristics rather than the power, which reduces the design complexity. Maximum power delivery from the source to the load is guaranteed through the load-side control. The introduction of shunt measurement in the hydraulic analogy through a parallel combination of high-flow rate sensing (via MHPGs) and highly sensitive ultrasonic mL/min sensor would allow micro-leaks to be detected. Unlike conventional water leak- age detection systems, the proposed automated system is highly sensitive (detected leaks of 1 mL/min.) and does not impede the main flow. Wavelet de-noising analyses carried out removed background noise and further isolated micro-leakage signals.