A method for controlling an operation of an inverter, comprising: determining (S31) whether a direct current side voltage of the inverter is greater than an operation voltage setting threshold; and in a case that the direct current side voltage of the inverter is not greater than the operation voltage setting threshold, controlling (S32) the inverter to operate according to a five level control strategy; and in a case that the direct current side voltage of the inverter is greater than the operation voltage setting threshold: adjusting (S33) the direct current side voltage by using a maximum power tracking algorithm; adjusting (S34) linearly a floating capacitor voltage of the inverter based on the adjusted direct current side voltage; determining (S35) whether the adjusted floating capacitor voltage is in a preset range, wherein the preset range ranges from a quarter of the operation voltage setting threshold minus a preset threshold to a quarter of the operation voltage setting threshold plus the preset threshold; and controlling (S32) the inverter to operate according to a five level control strategy in a case that the adjusted floating capacitor voltage is in the preset range; and controlling (S36) the inverter to operate according to a seven level control strategy in a case that the adjusted floating capacitor voltage is not in the preset range. determining (S31) whether a direct current side voltage of the inverter is greater than an operation voltage setting threshold; and in a case that the direct current side voltage of the inverter is not greater than the operation voltage setting threshold, controlling (S32) the inverter to operate according to a five level control strategy; and in a case that the direct current side voltage of the inverter is greater than the operation voltage setting threshold: adjusting (S33) the direct current side voltage by using a maximum power tracking algorithm; adjusting (S34) linearly a floating capacitor voltage of the inverter based on the adjusted direct current side voltage; determining (S35) whether the adjusted floating capacitor voltage is in a preset range, wherein the preset range ranges from a quarter of the operation voltage setting threshold minus a preset threshold to a quarter of the operation voltage setting threshold plus the preset threshold; and controlling (S32) the inverter to operate according to a five level control strategy in a case that the adjusted floating capacitor voltage is in the preset range; and controlling (S36) the inverter to operate according to a seven level control strategy in a case that the adjusted floating capacitor voltage is not in the preset range. adjusting (S33) the direct current side voltage by using a maximum power tracking algorithm; adjusting (S34) linearly a floating capacitor voltage of the inverter based on the adjusted direct current side voltage; determining (S35) whether the adjusted floating capacitor voltage is in a preset range, wherein the preset range ranges from a quarter of the operation voltage setting threshold minus a preset threshold to a quarter of the operation voltage setting threshold plus the preset threshold; and controlling (S32) the inverter to operate according to a five level control strategy in a case that the adjusted floating capacitor voltage is in the preset range; and controlling (S36) the inverter to operate according to a seven level control strategy in a case that the adjusted floating capacitor voltage is not in the preset range. <EOS>