Abstract: The H∞ robust controller design of AC/DC power system is investigated in this paper. Firstly, a novel fifth-order uncertain non-affine nonlinear model is put forward. The proposed model can describe both the dynamics of DC and AC systems. Then, an H∞ robust controller is constructed by employing the texonomy design principle. It is shown that through the firing angle control of the DC system converters, the stability can be improved and the robust performance can be guaranteed. Simulation results illustrate the effectiveness of the proposed control strategy.