Implementation of a Novel Digital Active EMI Technique in a DSP-Based DC–DC Digital Controller Used in Electric Vehicle (EV)

With ever increasing green-house gas emissions from fossil fuel-driven automobiles leading to acute environmental pollution, and ever depleting reserves of fossil fuel, today need for the development of pure electric vehicle (EV) is of utmost importance. Presently, there is an immense impetus to develop plug-in EVs. High switching frequency and high-power ac-dc PFC converter with an isolated output and a dc-dc isolated converter are essential systems for transferring from utility mains to the different battery packs which store energy for propelling the EVs. Electromagnetic compatibility (EMC) with strict regulatory standards is an essential requirement which any switch mode power converter must comply with not only for its own operation but also for safe and secure operation of surrounding electrical equipment. EVs possess many sophisticated electronic circuits in the vicinity of the battery charging power converters, so strict EMC standards of the on-board power converters should be met. For a cost-effective design approach, EMC should be considered at the primitive stages of the power converter design. The most commonly used passive electromagnetic interference (EMI) filters used for EMI mitigation in power converters come at the expense of cost, size and weight, power losses, and printed circuit board (PCB) real estate. In this paper, a novel embedded digital active EMI filter (DAEF) integrated into the DSP-based digital controller of a dc-dc converter applicable for charging the low-voltage battery bank of an EV is proposed and analyzed. Experimental results and comparison of the performance of the proposed embedded DAEF with a conventional EMI filter are presented in this paper so as to validate the feasibility of the proposed EMI filter and its advantages over the conventional one.