Statistics-Based Algorithm to Reduce Grid Harmonics due to EV Chargers

The growing global market of electric vehicles (EVs) increasingly needs fast charging stations to be installed at many facilities such as university campuses, shopping malls, hospitals, parking facilities etc. When consumers start plugging EVs in large numbers, the grid power quality is expected to deteriorate. This paper proposes a new statistics-based algorithm to reduce the grid harmonics caused by EVs acting essentially as non-linear loads. The proposed algorithm helps reduce grid harmonics by phase-shifting the carrier-wave of each converter within a charging station so that some of the harmonics will cancel each other. This new technique does not require any centralized communication or information exchange between the charging bays to coordinate the carrier-waves. As an example, the algorithm is implemented in a charging station with 20 bays by utilizing the Mean values of the Cumulative Poisson Distribution. The methodology is simulated using the MATLAB Simulink platform. Results show an improvement of nearly 30% in the THD of the grid voltage.