In recent years, the use of VSCMG/IPACS for satellites has been considered, because Earth observation satellites are required to have agility and miniaturization. However, in previous research, the control laws of VSCMG/IPACS at large-angle and agile attitude maneuvers have not been studied. In this study, we clarify that it is impossible for conventional methods to achieve large-angle and agile attitude maneuvers, while accurately tracking power. Therefore, we propose a system capable of simultaneous satellite attitude control and power tracking with VSCMG during large-angle and agile attitude maneuvers. The proposed steering law switches the steering laws according to singularities, and enables the satellite to change attitude quickly without power errors. In addition, numerical simulations demonstrate through comparison that the proposed steering law is more useful than conventional steering laws.