State observation control strategy of bidirectional resonant DC/DC converter in building DC system

This paper proposes a state observation control method for a bidirectional CLLLC resonant converter to solve the problem of output voltage stability of an isolated bidirectional DC-DC converter in building DC power distribution systems. Combining time domain and frequency domain analysis, this paper presents the modelling process of CLLLC converter from equivalent circuit analysis, harmonic approximation to extended description function rewriting. Then the design process of the state observation control method is given, that is, the linearization analysis is carried out according to the modelling results of the extended description function, the state equation of the converter is obtained, and the state observer and controller are designed according to the modern control theory. Finally, a full-bridge CLLLC converter experimental platform is built. Experimental results show that the control method designed in this article can achieve steady-state recovery of the output voltage under millisecond-level load switching, and is superior to PI control in terms of overshoot and steady-state performance. This paper proposes a state observation control method for a bidirectional CLLLC resonant converter to solve the problem of output voltage stability of a bidirectional DC-DC converter in building DC power distribution systems. The control method designed in this paper can realize the steady-state recovery of the output voltage in the case of load switching within milliseconds, and the voltage fluctuation is extremely small. image