Abstract: Dual active bridge(DAB) has been widely used in power systems due to its high power density, flexible controllability, and also adapting to the power conversion needs in different application scenarios; however, when the input voltage at both ends of the DAB transformer does not match the output voltage, the return power will increase significantly. To address this problem, a segmented optimal control strategy is proposed. Firstly, according to the characteristics of triple phase shift(TPS), the inductor current model is established, and the value range of the shift ratio of the return power is deduced; then, the critical point of the output power is defined by the shift ratio, and the output power is controlled by segmentation, and the simulation is carried out in MATLAB/Simulink, which shows that the circuit can realize the zero-return-power operation state in the range of the output power.