A parallel-variable speed operation system using multiple large-scale wind turbines is proposed in order to reduce fluctuations in the generated power output. In this operation, the electric power outputs of load induction generators are connected to one large-capacity PWM converter. The rotational speeds of the wind turbines can be controlled by only one converter because they are restrained by a converter-impressed frequency. This operation aims not only to reduce power output fluctuations by using large moment of inertia of the multiple rotors but also to improve the generating performance by adequately controlling the rotational speed in response to variations in inflow wind speeds. As the first feasibility study for this system, this study analyzes the target operating point of the system, which means the maximum power output point under different wind speed to each wind turbine, through a numerical simulation.
