New parameter for current-sensorless MPPT in grid-connected photovoltaic VSIs

This paper a new quantity for current-sensorless power-angle-based MPPT for single-stage grid-connected photovoltaic voltage-source inverters (VSIs). The proposed tracker eliminates the use of the current sensor by using only the voltage sensor: The current sensor is substituted with a new quantity, which is the sine value of the power-angle (the phase angle between the inverter output voltage and the power grid voltage). A theoretical proof for this quantity is developed and is provided. Then the controller is designed and implemented using a digital signal processor (DSP). Algorithms are configured on a fixed point DSP TMS320F2812. Moreover, a breadboard has been built-up for testing the use of the proposed tracker with a single-stage grid-connected photovoltaic voltage-source inverter. Both of simulation and experimental results show that the proposed tracker attains a satisfactory performance. On the other hand, it requires a good control tool to accurately achieve the arithmetic calculations. A substantial part of the manufacturing cost and complexity burdens of MPPTs involves the use of current sensors. Considering this investigation saves cost, decreases complexity, and therefore increases the power density of the MPPTs.