Inverting apparatus for avoiding misjudgement of maximum power point tracking operation and control method thereof

An inverting apparatus, comprising:

• an inverting circuit, receiving a direct current (DC) input power, and converting the DC input power into an alternating current (AC) output power;
• a detection circuit, detecting an input voltage and an input current of the DC input power under a plurality of time points;
• and
• a control circuit, coupled to the inverting circuit and the detection circuit, and providing a control signal for controlling the inverting circuit to disturb the input voltage, so as to adjust a voltage value of the input voltage to a command voltage represented by the control signal, wherein the control signal corresponds to the command voltage,
• wherein the control circuit calculates an input power corresponding to each of the time points according to the input voltage and the input current, calculates a power variation between a disturbed input power and an undisturbed input power,
• when the power variation is determined to be greater than a predetermined variation, the power variation reflects a power difference caused by a variation of the input voltage, the control circuit determines the power variation to be a valid power variation, and a disturbance quantity is set based on a maximum power point tracking operation, wherein the maximum power point tracking operation is to compare the disturbed input power and the undisturbed input power, so that the input power approaches a maximum input power, and
• when the power variation is determined to be smaller than or equal to the predetermined variation, the power variation is another power difference caused by system noise, the control circuit determines the power variation to be an invalid power variation and does not perform the maximum power point tracking operation according to the power variation, and the disturbance quantity of a current time point is set according to a disturbance direction of the command voltage of a previous time point, such that the command voltage is increased or decreased along the disturbance direction of the command voltage of the previous time point.