An Input-Series Output-Series Noninverting BuckBoost Converter for 1500 V DC Bus With Wide Input and Output Voltage Ranges

This article proposes the input-series output-series noninverting buck-boost converter (ISOSNIBBC) with wide input and output voltage ranges. The proposed ISOSNIBBC is composed of noninverting buck-boost converters in series and a coupled inductor. Compared to traditional series-connected converters, the proposed converter has advantages of simple structure, intuitive voltage gain, high reliability, and easy modularization using industry standard power modules. Small signal models and operating modes of the proposed converter are suggested and analyzed. After that, the voltage and the current controllers are qualitatively designed using the derived models. To validate the proposed converter and controllers, the 8-kW converter prototype for 1500 V dc bus system has been built and tested. Both the simulation and the experimental results verify the operating mode analyses, the small signal models, and the designed controllers. The experimental results confirm that the proposed converter has various power processing capabilities required in 1500 V dc applications.