Speed Control of PV-Fed BLDC Motor with Energy Storage Integration Using Modified Adaptable Step-Size P&O MPPT Technique

This paper presents a proportional-integral (PI) controller-based speed control mechanism for a PV array-fed electronically commutated brushless direct current (BLDC) drive system integrated with a Li-ion battery as an energy storage solution. The proposed system employs a 2-channel direct coupled interleaved boost (2C-DCIB) converter to improve ripple content and perform forward stage voltage boosting operation. To optimize the power extraction from the PV array, a modified adaptable step-size P&O (MASP) MPPT technique is utilized. This technique dynamically adjusts the step size in response to the rate of change in power, voltage and current ensuring faster to reach the true maximum power point (MPP) of the array under varying weather conditions with reduced steady-state oscillation and less power loss. The integration of the Li-ion battery through bidirectional DC-DC converter (BDDC) provides additional energy buffering during fluctuating solar irradiance. Simulation results validate the efficacy of the proposed control strategy, showing that the motor speed closely follows the reference speed command even under dynamic irradiation profiles. The DC-bus voltage exhibits minimal fluctuations despite variations in solar power input, demonstrating the controller's ability to regulate voltage consistently and ensure stable power delivery to the motor, making it suitable for various solar-powered applications, including aqua pumping with varying flow rates.