Efficiency Improvement of a High Power “Power Distribution Unit” at Low Power Demands Using Ultracapacitor

摘要

Electric two-wheelers have a Low voltage Power Distribution Unit (PDU) which caters to peripheral loads that operate on the lower voltage platform. PDU works at high efficiency at medium to high loads and low efficiency at low loads. In parked mode of the vehicle, the peripheral loads are very low during which the PDU operates inefficiently for long periods of time. At high load, the conduction loss is higher, at low load, the gate driving loss and switching loss dominate due to the relatively small conduction loss. This paper presents a synchronous buck converter based high power PDU which is used with ultracapacitor (as secondary power unit) to improve the overall power unit's efficiency at low load demands. In the proposed topology, buck converter charges the ultra-capacitor and caters to high power loads leading to high efficiency while low load demand is catered to by ultracapacitor and buck converter is turned off, thus the overall efficiency of the system increases at both high and low power loads. Various matlab/simulink simulations are analyzed/presented to observe the same.