This paper presents a DC smart grid to achieve suppression of DC bus voltage fluctuation by using controllable loads and
stabilizing control for the connected AC grid. The power fluctuation, due to generations utilizing natural energy and demand loads, is suppressed by current control of controllable loads based on droop characteristics. Therefore, each decentralized controllable load is operated to suppress the power fluctuation, and the following are achieved without any communication: the generating power smoothing of the output power of diesel generator and the suppressing DC bus voltage fluctuation. There are some advantages that the wind power generator and photovoltaic generation are able to operate at maximum power point: reduction in cost by reduction in storage equipment for natural energy power facility and augmentation of controlability of system frequency and DC bus voltage. Consequently, electricity companies can expect high quality power supply and reduce the cost by cooperative control between supply side and
demand side in the future.