To suppress chaotic oscillation in a seven-dimensional power system model, a simple chaos control method based on auto-coupling proportional-integration-differential (ACPID) control theory is proposed. First, the seven-dimensional chaotic control problem is decomposed into the control problem of three strict feedback subsystems. Then, the known and unknown dynamics of each subsystem are defined as a total disturbance. Then, the three subsystems are equivalently mapped to a third-order linear disturbance system and two second-order linear disturbance systems. Based on this, three controlled error systems under the total disturbance inverse excitation are constructed. From ACPID control theory, an extended auto-coupling proportional-differential (EACPD) controller and two auto-coupling proportional-differential (ACPD) controllers are designed. Finally, the robust stability and anti-disturbance robustness of each subsystem are analyzed. The simulation results verify the effectiveness of the control method, which can make the seven-dimensional power system enter the steady state from the chaotic oscillation state, and the control signal is smooth. Therefore, it has a good practical application prospect in the field of power chaotic oscillation control systems.