SiC-Based Bidirectional Ćuk Converter With Differential Power Processing and MPPT for a Solar Powered Aircraft

A silicon-carbide (SiC)-based dc–dc converter is developed for the solarship, a manned solar aircraft for supply delivery in remote locations. The concept of differential power processing (DPP) is utilized to realize a high-efficiency lightweight converter that performs maximum power point tracking (MPPT) to transfer power from the aircraft’s wing-mounted solar array to the high-voltage lithium-battery bus. The isolated Ćuk topology is augmented with an unfolder to achieve four quadrant operation and minimize the worst-case processed power. A small-signal model is derived for control design, and it is shown that the compensation strategy differs significantly based on the operating mode. The 2.7-kW prototype is verified at a high frequency (200 kHz), high efficiency ($>98\%$), small mass (0.604 kg), and uses no electrolytic capacitors. MPPT operation is verified on a 376-V commercial solar installation. The DPP Ćuk converter is promising for emerging solar aerospace applications.

I. Introduction

The global trend toward reducing fossil fuel consumption and greenhouse gas emissions has accelerated the development of electric vehicles (EVs). EVs can reduce emissions by up to 92% [2] compared to conventional internal combustion engine (ICE) vehicles. The International Energy Agency has set a goal of 20 million EVs on the road by 2020 [3], and projections indicate that Norway may surpass 200 000 chargeable vehicles (hybrid and EV) by 2020 [4]. EVs can draw their energy from clean renewable energy resources such as wind and photovoltaics (PVs)  [3]. Using on-board PV modules in EVs has also been widely investigated despite the limited available surface area, [5]–[8] and is the basis for the world solar challenge race in Australia.