Abstract: For realizing the excitation and synthetic speed control of an electromechanical velocity modulated diesel-generator set,a new decentralized L₂ attenuation control for an interconnected multi-input system is proposed and the corresponding formula is calculated. In the new control method,because the K-class functions are used in the control law,the convergence speeds of the state parameters and the L₂-gain attenuation ability are improved. The simulation results show that when the loads are increased suddenly,the new proposed method can increase the convergence speed and the performance of the terminal voltage can also improve the disturbance attenuation ability. This is achieved by using the K-class functions in comparison to the traditional non-linear robust adaptive control method.