A power supply system comprising: a generator power conditioner configured to switch between a grid connecting operation and a grid independent operation, the generator power conditioner being configured to carry out power conversion of a solar battery and to coordinate with a power grid in the grid connecting operation, the generator power conditioner being configured to be disconnected from the power grid in the grid independent operation; and a charging-discharging power conditioner connected to a grid-independent feed line which serves as a power supply line for the generator power conditioner in the grid independent operation, characterized in that the charging-discharging power conditioner comprises: a charge-discharge circuit configured to charge and discharge a storage battery; a voltage sensor configured to sense a voltage of the grid-independent feed line; and a controller configured to control the charge-discharge circuit so as to maintain a voltage of the grid-independent feed line sensed as a sensed voltage by the voltage sensor at a predetermined target value in the grid independent operation by switching the charge and discharge of the storage battery, and wherein the controller is configured to control the charge-discharge circuit to: charge the storage battery by electric power supplied through the grid-independent feed line when the sensed voltage is greater than the target value; and supply electric power from the storage battery to the grid-independent feed line when the sensed voltage is smaller than the target value. a generator power conditioner configured to switch between a grid connecting operation and a grid independent operation, the generator power conditioner being configured to carry out power conversion of a solar battery and to coordinate with a power grid in the grid connecting operation, the generator power conditioner being configured to be disconnected from the power grid in the grid independent operation; and a charging-discharging power conditioner connected to a grid-independent feed line which serves as a power supply line for the generator power conditioner in the grid independent operation, characterized in that the charging-discharging power conditioner comprises: a charge-discharge circuit configured to charge and discharge a storage battery; a voltage sensor configured to sense a voltage of the grid-independent feed line; and a controller configured to control the charge-discharge circuit so as to maintain a voltage of the grid-independent feed line sensed as a sensed voltage by the voltage sensor at a predetermined target value in the grid independent operation by switching the charge and discharge of the storage battery, and a charge-discharge circuit configured to charge and discharge a storage battery; a voltage sensor configured to sense a voltage of the grid-independent feed line; and a controller configured to control the charge-discharge circuit so as to maintain a voltage of the grid-independent feed line sensed as a sensed voltage by the voltage sensor at a predetermined target value in the grid independent operation by switching the charge and discharge of the storage battery, and wherein the controller is configured to control the charge-discharge circuit to: charge the storage battery by electric power supplied through the grid-independent feed line when the sensed voltage is greater than the target value; and supply electric power from the storage battery to the grid-independent feed line when the sensed voltage is smaller than the target value.