Recently, photovoltaic generation systems and wind turbines are widely installed to power system. However, the power system has to supply electric energy with high quality to our society under high reliability conditions, as electric energy is necessary for society today. But, the output power of such distributed energy resources based on natural resources is inherently variable along to the variation of natural resources.
In the circumstances, power system engineers have to challenge to keep the system frequency and voltage by available control technologies.

On the other hand, increasing power rating of the semiconductor power devices and the progress of the static power conversion technologies result in advanced applications of high power self-commutated voltage source converters. It means that the electric power can be modified and controlled freely, today. In addition, a storage battery becomes to have a high capacity, then, the electric energy can be placed widely in the power system. Therefore, the combination of the self-commutated voltage sourced converter and energy storage leads to high possibility of new power electronics applications.

In this research, cooperative control between the distributed energy resources and power system is applied to the utility interactive inverter, which used to generate electric power along the natural resources.

First, the output voltage controller regulates the phase angle of the output voltage in order to regulate the system frequency.
For example, when the system frequency is decreased, the output voltage will be slightly regulated to compensate the insufficient power, or vice versa. To regulate the terminal voltages, the amplitude of the output voltage is regulated.
This controller has an advantage to modify the contributions of cooperative control only by single control gain. Contributions of the distributed energy resources to the power system means that some amount of energy is consumed by this short trip.

Next, an advanced application of the proposed control is equipped to a Virtual Power Plant (VPP), which combines some distributed energy resources to be a power plant. The VPP can totally achieve a high power rating, then its control effects is improved.

The proposed control scheme will be equipped onto an experimental setup as well as tested by simulation study.