A Gallium Nitride Based High Bandwidth, Extended Single-Ended Primary Inductance Converter, for Fast Balancing of Ultracapacitors

Abstract

Ultracapacitors (UCs) are the preferred choice for specific power requirements. Series and parallel of UCs are required to match the required voltage and power, as the available voltage range is 2.5 to 3 VDC. Passive and active balancing is inevitable here, while some demand, high bandwidth control for fast balancing and stable operations. A novel Extended-Single Ended Primary Inductance Converter (E-SEPIC) is used to actively balance the UCs. A new, simple and effective method is formulated to achieve a higher Degree of Balancing of UCs. A two-stage E-SEPIC with Silicon (Si) and Gallium Nitride (GaN) switch based are demonstrated with an input of 12 VDC to balance up to 3 VDC UCs at the output for high bandwidth and high-power density properties. An effective method of emulating impedance of UCs using Hybrid Electro-chemical Impedance Spectroscopy is evolved. The devised novel method of balancing is effective in height of balancing with GaN based converter exhibiting higher bandwidth of around 30 kHz around 18 times better, with increased efficiency of 12% with an improved power-density of 8.25 times in comparison with that of Si based. This contribution of GaN properties in electrical performance enhancements has influenced the design of Power Electronics applications.