A system and method for operating a photovoltaic element at or near a maximum power point. A maximum power point tracker changes a voltage or current set point of a photovoltaic element in sequential discrete steps, measuring an output power at each step after a predetermined settling time. A slope of a power-voltage curve is then estimated and the slope is corrected for irradiance changes. Finally, an operating voltage or current of the photovoltaic element is adjusted based on the slope of the power-voltage curve and other factors, causing the photovoltaic element to operate at or near its maximum power.