Comparison of MPPT Strategies in Three-Phase Photovoltaic Inverters Applied for Harmonic Compensation

The main objective of a photovoltaic (PV) inverter is to inject the PV power into the ac grid. Generally, due to variations in solar irradiance, inverters operate below their rated current. Therefore, this current margin can be used to perform ancillary services, such as reactive power control and harmonic current compensation. However, it is necessary to evaluate the effects of these ancillary services on the converter. The harmonic current compensation, for example, affects the efficiency of the maximum power point tracking (MPPT) algorithms. Therefore, this paper presents a mathematical modeling that relates the harmonic current compensation with the oscillation in the dc-link capacitor voltage, validated through simulation and experimental results. Simulation results show the instantaneous and dynamic efficiency of MPPT algorithms during rapidly irradiance variations and harmonic current compensation. The results lead to the conclusion that all MPPT strategies tested have faced degradation in efficiency due to harmonic current compensation.