Hybrid MPPT Method for Controlling an Open-Channel Hydrokinetic Microgenerator in Grid-Connected Mode

Abstract

Hydrokinetic energy conversion has been gaining prominence among renewable energy sources due to its reasonable predictability and low environmental impact. In this context, this paper proposes the development of a maximum power point tracking (MPPT) algorithm for controlling a 10-kW hydrokinetic microgenerator in grid-connected mode. To maximize energy capture and ensure operational reliability, the strategy employs a hybrid process that uses the fixed-step “perturb and observe” (P&O) method to fine-tune the search within the high-efficiency region, established based on the unit’s V–P (voltage–power) curve scan. The power stage consists of an in-stream turbine, a permanent magnet synchronous generator (PMSG), an uncontrolled rectifier, and a voltage source inverter. The control stage integrates the MPPT subsystem, along with a DC-link voltage regulator, output current compensators, phase-locked loops (PLLs), an islanding detector, and pulse width modulation (PWM) devices. The technique was validated using a simulation-based approach on the MATLAB/Simulink® platform, achieving an average tracking factor (TF) of 96.21% under varying flow conditions. Comparative results suggest that the algorithm makes the controller robust to small changes in plant parameters, such as those from mechanical wear, as the tolerance of the characteristic curve effectively mitigates their impact on the conversion rate