Multiple-port dc–dc converters are characterized by a variety of kinds and a large number of circuit topologies. In this article, we aim to reveal the intrinsic relationship among the topologies of multiple-port dc–dc converters and propose the topology derivation method. First, the voltage- and current-type ports are summarized from basic dc–dc converters, and the approach of converting current-type ports into voltage-type ports is discussed. Then, according to Kirchhoff's law, four types of multiple-input multiple-output converters named input-port-series output-port-series, input-port-series output-port-parallel, input-port-parallel output-port-series, and input-port-parallel output-port-parallel are presented. Second, the topology derivation method of multiple-port bidirectional dc–dc converters based on the voltage-type ports is studied in terms of power flow paths in various operation modes, and then the topology optimization method is proposed. Particularly, a flow diagram for the optimal design procedure is given to guide the topology derivation for some specific requirements. Based on the proposed approach, a family of multiple-port dc–dc converters can be derived, which provides lots of viable candidates for practical engineering. Furthermore, one derived converter named the parallel-type three-port bidirectional buck converter is analyzed in three operation modes to demonstrate the topology derivation. Finally, the effectiveness of the above theoretical analysis is verified by those experimental results.

In this paper, the slow-scale instability in a boost PFC converter under average current mode control is studied via the harmonic balance method and floquet theory. Systematic and general numerical algorithm of the technique is developed. The objective is to identify instability of the system. If instability exists, the type of bifurcation and the boundaries of slow-scale instability in the parameter space of the system can be found for facilitating the design of such converters. Firstly, based on the fact that the current compensator is designed very well and what we considered is the slow-scale instability, the simplified model of a boost PFC converter under average current mode control is derived. And then, the solution of the simplified model is calculated by using the harmonic balance method. Subsequently, both the stability of the circuit system and the type of bifurcation are identified via floquet theory. Meanwhile, the critical conditions of the stable operation in the parameter space of the system are given accurately. Finally, experimental results are presented for the verification of the analytical results.

A novel Z-source dual-bridge matrix converter (ZSDBMC) topology and its control strategy are proposed to overcome two main drawbacks of conventional matrix converters: low immunity to abnormal input voltage disturbance and low voltage transfer ratio. The boost voltage characteristic of Z-source network is utilized to improve the system voltage transfer ratio and make it immune to abnormal input voltage disturbance with shoot-through duty cycle self-adjusted. Meanwhile, nonlinear PID controller is employed to eliminate effects caused by nonminimum-phase characteristic presented in Z-source network and improve system dynamic performance and robustness. Moreover, a comparison of the topology respect a standard back-to-back converter, Dual bridge matrix converter and ZSDBMC was provided. Finally the operation principles and validity of this proposed ZSDBMC topology are analyzed in details and verified by simulation and experiment results.