Abstract
This paper introduces an improved current-sensorless maximum power point tracking (MPPT) approach, coupled with a battery charging unit, specifically designed for single-phase standalone photovoltaic (PV) power systems. An interleaved hybrid DC-DC boost converter with high voltage gain, previously developed by the authors, is used to boost the low and non-linear voltage output of the PV array to the usable DC grid voltage level. Since the energy yield of PV systems is highly sensitive to variations in solar irradiance, fast and accurate tracking of the maximum power point (MPP) is essential. Unlike conventional MPPT techniques that rely on both voltage and current measurements, the proposed method estimates the input current using only the inductor voltage observed during the switch ON-state, thus removing the need for direct current sensing. This sensorless approach simplifies hardware design and reduces implementation costs, particularly in experimental environments where current sensors may introduce complexity and noise susceptibility. In addition, the proposed system includes a battery charging unit which ensures effective energy transfer to the battery in isolated operating conditions for single-phase AC off-grid power applications. The control structure regulates charging dynamics based on voltage behavior and operating constraints, contributing to stable performance under changing environmental conditions. The system's effectiveness is verified through MATLAB/Simulink simulations under dynamic irradiance profiles. Predicted and actual current values are compared to validate estimation accuracy. Furthermore, experimental validation using a digital signal processor (DSP) demonstrates reliable real-time operation, confirming the practical applicability of the proposed method in cost-sensitive, off-grid solar energy systems.