Apparatus and method for tracking maximum power point in solar photovoltaic system

An MPPT(Maximum Power Point Tracking) apparatus and an MMPT method in a photovoltaic system are provided to track a maximum power point stably by using a voltage error signal inside a voltage control loop. A voltage sensor(206) measures an output voltage of a boost chopper(202). A voltage error calculator(208) calculates a voltage error value between the voltage measured by the voltage sensor and a preset voltage estimation value. A variable PI(Proportional-Integral) controller(210) generates a PI control signal for the voltage error value with an integral gain for increasing the output voltage of the boost chopper when the voltage error value exceeds a preset voltage error permissible range value and generates a PI control signal for the voltage error value with an integral gain for reducing the output voltage of the boost chopper when the voltage error value does not exceed the preset voltage error permissible range value. A PWM(Pulse Width Modulation) signal generator(212) generates a PWM signal for controlling a switching operation of a semiconductor switch constituting the boost chopper according to the PI control signal.