A Family of Scalable Non-Isolated Interleaved DC-DC Boost Converters With Voltage Multiplier Cells

Abstract

In this paper, a family of non-isolated interleaved high-voltage-gain DC-DC converters is presented. This family can be used in a wide variety of applications, such as in a photovoltaic systems interface to a high voltage DC distribution bus in a microgrid and an X-ray system power supply. The general structure of this family is illustrated and consists of two stages: an interleaved boost stage and a voltage multiplier stage. The interleaved boost stage is a two-phase boost converter, and it converts the input DC voltage to an AC square waveform. Moreover, using the interleaved boost stage increases the frequency of the AC components so that it can be easily filtered with smaller capacitors and, therefore, makes the input current smoother than the one from the conventional boost converter. The voltage multiplier cell (VMC) can be a Dickson cell, Cockcroft-Walton (CW), or a combination of the two. The VMC stage rectifies the square-shaped voltage waveform coming from the interleaved boost stage and converts it to a high DC voltage. Several combinations of VMCs and how they can be extended are illustrated, and the difference between them is summarized so that designers can be able to select the appropriate topology for their applications. An example of this converter family is illustrated with detailed modes of operation, a steady-state analysis, and an efficiency analysis. The example converter was simulated to convert 20 V DC to 400 DC , and a 200 W hardware prototype was implemented to verify the analysis and simulation. The results show that the example has a peak efficiency of 97% of this family of converters and can be very suitable for interfacing renewable energy sources to a 400 V DC DC distribution system.