Research on fractional order modeling and PIλ control strategy of CLLC bi-directional resonant converter

Abstract There are problems such as insufficient modeling accuracy of the CLLC bi-directional resonant converter in integer order, failure to accurately describe the actual conditions of the system, poor dynamic performance of classical PI control strategy, and failure of the system to reach the stable state quickly and smoothly. First, based on the fractional order calculus theory, this paper proposes an extended describing function method based on fractional order, establishes the mathematical model of the fractional order and small signal model of the fractional order of the CLLC bi-directional resonant converter, obtains the fractional order transfer function of the system, constructs the PI λ control strategy of the fractional order of the CLLC bi-directional resonant converter, and builds the simulation model of the CLLC bi-directional resonant converter based on Matlab/Simulink software for simulation verification. Finally, a principle prototype was built in the laboratory to verify the correctness and feasibility of the CLLC bi-directional resonant converter of the fractional order and theoretical analysis of the PI λ control strategy of the fractional order.