Chopping Compensation Control and Low Frequency Pulse Suppression Strategy of DC Side Current in Lithium Battery Energy Storage System
摘要
To resolve the issue of lithium-ion batteries in electromagnetic emission work environments experiencing voltage drop at the battery output due to high rate discharge, which in turn cannot meet the DC voltage requirements of the load converter. Therefore, this article proposes an N+1 level dynamic chopping structure energy storage system topology to compensate and stabilize the DC bus voltage. Meanwhile, in order to improve DC bus voltage compensation performance, this paper adopts a composite compensation control strategy of LADRC+PI. In response to the problem of negative saturation caused by initial feedback in the LADRC controller, this article uses the method to start the observer feedback by judging the DC bus voltage and the reference voltage. Secondly, in order to reduce the three fold fundamental frequency ripple on the DC side caused by the modulation strategy of the load inverter, the bus voltage feedback value filtered by a notch filter is used for feedback to suppress the DC side current ripple. Finally, the above strategies were validated through the RT-LAB experimental platform.