Pt. Staats et al., A STATISTICAL-METHOD FOR PREDICTING THE NET HARMONIC CURRENTS GENERATED BY A CONCENTRATION OF ELECTRIC VEHICLE-BATTERY CHARGERS, IEEE transactions on power delivery, 12(3), 1997, pp. 1258-1266
This paper presents a method for predicting the net harmonic currents
produced by a large number of electric vehicle (EV) battery chargers.
The problem is stochastically formulated in order to account for rando
mness in individual charger start-time and battery state-of-charge. We
introduce a model that allows for partial harmonics cancellation due
to diversity in magnitudes and phase angles. A general solution techni
que is presented along with an example using data from a commercially
available EV charger. Our results show that a limiting distribution of
7-10 chargers is adequate for accurately predicting harmonic injectio
n currents using the Central Limit Theorem. We also show that the expe
cted values of net harmonic currents are considerably less than the pe
ak values that would have been realized if the same number of chargers
were operated in unison.