The triple active bridge DC-DC converter (TAB) has the advantages of high-power density

electrical isolation

and flexible control

and has a promising application prospect in direct current grids. The internal circulating power is large in the conventional single-phase shift control strategy of the TAB converter

resulting in an increase in reactive power and loss for the converter. To solve this problem

this paper proposes a fundamental-wave optimal control strategy of circulation aimed at reducing reactive power. Starting from the basic principles of the TAB converter

a mathematical model of the TAB converter is constructed using Fourier series decomposition and phasor analysis

and expressions for active and reactive power at the output port are obtained. Then

particle swarm optimization (PSO) is used to solve the optimal phase shift Angle in the global scope

and the corresponding control strategy is constructed. By changing the load analog power mutation

the response characteristics of the output port under the single-phase shift control strategy and the optimal control strategy proposed in this paper are compared and analyzed. Simulation and experimental results demonstrate that the optimization control strategy proposed in this paper can effectively reduce reactive power at the output port and enhance system efficiency when the output power undergoes a sudden change.