Design and Implementation of an Analog Controller Based on K-factor Design Method for a Novel Isolated Z-Source DC-DC Converter with High Voltage Gain

Abstract

In this study, a closed-loop analog controller design and implementation is achieved for a novel isolated Z-source dc-dc converter with high voltage gain by using K-factor design method. The novel structure of the converter complicates the design of an effective closed-loop controller that guarantees high performance under all conditions. Within this context, a small signal model is developed to reflect the dynamics of the converter. By using the bode diagram obtained from the small signal model, the error amplifier circuit is designed with the K-factor design method. Simulation study is performed in PLECS to verify the design. Applying the experimental study, the results are compared with the simulation study. The results of the study prove that the control system designed with the K-factor design method works successfully. Figure A. The overall block schema of a closed-loop controlled dc-dc converter Purpose:The main purpose of this study is to ensure that the output voltage of a novel Z-source dc-dc converter supplies a stable and constant output voltage despite the variations in input voltage and load within certain limits. The converter is turned into a closed loop system with analog control method. In order to achieve this purpose, the K-factor design method used for error amplifier circuit design and the small signal model used for this method are explained. Theory and Method:The type-3 compensator is used to turn a novel Z-source dc-dc converter into closed loop system. Firstly, the small signal model required for the K-factor design method is obtained by using the PLECS. Secondly, the type-3 error amplifier circuit is designed by using the theoretical study and small signal model. Finally, the output voltage is analyzed by creating step changes in input voltage and load with simulation and experimental study.Results: 10% and 20% changes in the input voltage and 20% changes in the load of the dc-dc converter are implemented. Despite the changes, the output voltage provided by the converter remains constant with an error margin of 1%. Conclusion:In this paper, by using the K-factor design method, a novel Z-source dc-dc converter is turned into closed loop controlled system. Although the input voltage and load changes, the dc-dc converter continues to produce a constant output voltage with the created controller. The most important advantage of the method is that the K-factor design method has a certain flow of mathematical equations. The mathematical method makes the design process easier and safer. By means of implementing with a new generation dc-dc converter, a robust and reliable control method has been proved for a new generation converter.