Active Control of Power Sharing in a Battery/Ultracapacitor Hybrid Source

A regulator was built and evaluated to actively control the power sharing between a battery bank and a ultracapacitor bank. The ultracapacitor output is controlled using a boost converter to supply additional current demanded by the load beyond the desired battery current limit. The output port of the boost converter is connected to a 36V battery bank and a regulated buck converter to maintain output voltage. The current out of battery is sensed and is used to control the current of the boost converter. The system designed was able to maintain the battery current to a reference level while supplying the current needed by the load using ultracapacitor and has output power capacity of 350W.