Direct AC-AC converters are widely used in occasions where voltage regulation and stabilization are required,due to the obvious advantages like single-stage conversion,high efficiency,and small size of the converter.With the increase of load types in the direct AC-AC converter application,the requirements for the input current harmonics,voltage regulation range,and input power factor of the direct AC-AC converter circuit are gradually increasing.To further improve the performance of the direct AC-AC converter circuit to satisfy the needs of different types of loads,it is of great significance to study the direct AC-AC converter circuit and derive a novel direct AC-AC converter based on exploring the topology of the DC-DC converter circuit.Based on the principle of duality,this paper proposes a virtual gyrator dual circuit conversion and parameter analysis method for dual conversion of the DC-DC converter circuits in continuous operation mode.The method realizes the circuit dual conversion at the converter circuit level by introducing the rotation resistances of the virtual gyrator,the duty coefficient and the switching period(frequency)coefficient describing the influence of the switches.Meanwhile,the parameter relationship between the original circuit and the dual conversion circuit is established.Moreover,the method explores the unity between the original converter circuit and the dual conversion circuit.It provides a solution for the dual conversion of the DC converter and the parameter analysis of the circuit obtained from the dual conversion.According to the simulation results of the DC-DC converter,the feasibility and effectiveness of the method are verified.The relationship between the circuit structures of basic voltage-type and current-type DC-DC converter is analyzed based on the virtual gyrator dual circuit conversion and parameter analysis methods.On this Basis,a new topology of DC-DC converter is derived.Firstly,the deductive process between the basic voltage-type and current-type step-up or step-down DC-DC converter circuits is analyzed,through the introduction of the concept of equivalent power supply and conversion between voltage-type and current-type load.The relationship between the input and output expressions of the converter is deduced,and the relativity of the division of the electric energy conversion structure is revealed.Secondly,based on the relativity of the division of the electric energy conversion structure,two derivative step-up/down voltage DC-DC converters,two novel derivative up-and-down current DC-DC converters,and a dual-port output DC-DC converter are derived.Combining the analysis method of the DC-DC converter and the parameter analysis method of the virtual gyrator dual circuit,the circuit parameter expression of the converter and the relationship between input and output are deduced and verified by simulation.A novel high-power factor step-up/down voltage type direct AC-AC converter circuit is derived,based on the circuit topology of the derivative step-up/down voltage DC-DC converter.In this paper,the relationship between the input and output of the converter and the expression of the parameters of the main circuit components in the circuit are deduced,and the reasons for the high power factor of the converter and its influencing factors are analyzed.Through MATLAB/Simulink simulation and experimental prototype,the ability of the direct AC-AC converter to achieve step-up and step-down voltage conversion is verified.And it is verified in experiment that the converter can have a higher input power factor for inductive loads while satisfying the requirements for power quality in the Type C standard of IEC61000-3-2. |