Inverter control method and inverter apparatus using the method

摘要

A pulse width of a pulse train signal used for PWM (pulse width modulation) control is monitored. When a variation of the pulse width substantially disappears within a specified time, it is determined that an operating point on an output characteristic curve of a photovoltaic array is located on the open-circuit voltage side of a maximum power point. When the variation of the pulse width does not disappear after the elapse of the specified time, it is determined that the operating point is located on the short-circuit current side of the maximum power point. Based on the determination result, the inverter control is performed such that the operating point follows the maximum power point.