Low Frequency Magnetic Field Generated at Electric Vehicle's Charging Station

The electric vehicle is one alternative form of transportation that has gained importance over the last few years due, in part, to pollution-free operation. Electric vehicles in their charging mode generate magnetic fields. Over the last few years these fields have been investigated for possible health hazards. A study was undertaken to measure and evaluate the magnetic field generated within a charging station. The 1993 Arizona Public Service Solar and Electric 500, a race for solar and electric vehicles held at Phoenix International Raceway, offered an excellent opportunity to collect data on the magnetic field generated within a charging station. Quantification of the magnetic field is necessary to predict the level of the field, the location where the maximum field is generated, distribution of the field within the charging area, etc. An electric vehicle requires both periodic and fast charging times. These factors necessitate building a large number of charging stations in the future, each with sufficient capacity to service a large number of vehicles simultaneously. Therefore, the requirements of a charging station were also studied. The magnetic field was measured inside and around the charging trailer, along the charging cords and at four points around each of the electric vehicles in their charging mode. This paper characterizes the overall magnetic field generated in the charging station. The maximum field magnitude measured is 64.37 mG at a distance of 50 cm from the circuit breaker panels. Results show that a low frequency magnetic field is generated. The frequency range for the field is 60 - 420 Hz.