Energy storage system based on a bidirectional one-leg converter for educational purpose
Authors: Menendez-Villar, Victor ( http://orcid.org/0000-0003-1010-2097)
Abstract: An educational scale model of the power electronics of an energy-regenerating system (e.g. EV, e-bike, electric kick scooter) is proposed. Four LFP batteries connected in series make up the accumulator or battery pack. LFP technology has been chosen because it does not tend to deflagrate when abused by a user (short-circuited, overheated), and hence it is safer than other chemistries (such as LiCoO2 or LiMnO2). In addition, this battery pack could replace lead-acid batteries used all over the world in cars and motorbikes, since it has a similar voltage (12.8 V) but a lower weight and size. The power electronics module is connected to a DC low-voltage 24 V bus. It allows not only to power up the motor using the batteries, but also to regenerate energy if used in conjunction with a KERS. The DC-DC conversion is carried out by a Buck-Boost converter, which permits to adjust to any voltage both in the side of the battery and in the side of the motor, ensuring system stability. The employed control system is “droop” type, meaning that the bus current is proportional to the variation of its voltage around a nominal value. The sense of the flow (discharge or charge) is determined by the sign of this variation, which should not exceed 5 V. As for the control, a dsPIC will be used. No power higher than 50 W will be allowed in any sense. A commercial Battery Protection Circuit Module and driver will be included.
Digital Object Identifier (DOI): http://dx.doi.org/10.15592/workrooms.2016.0006
Date: July 2016
Keywords: Engineering Education, Energy Storage, One Leg Converter, Power Electronics, Droop Control.