Near Magnetic Field Emitted by the Used Driver in a Buck Converter

Energy conversion systems are used with increasingly higher switching frequencies. As a result, they impose increasingly severe electromagnetic interference (EMI) constraints on their environment. In order to quantify the radiated disturbances, we used a test bench to measure the radiated magnetic field in the near zone above a series chopper especially the IR2110 driver in the time and frequency domain by oscilloscope and spectrum analyser respectively. In this paper we present the impact of variation of signal parameters of the MOSFET driver (frequency, duty cycle) on the radiated magnetic field measured by the RSH50-1 probe of a Buck chopper. Comparing the results obtained with the limits of the CISPR 11 class A standard in the frequency range from 30 MHz to 1 GHz. Which must not exceed -67 dBm in the range [30 MHz – 230 MHz], and -60 dBm in the remaining range. We notice that the magnetic field measurement increases as function of the reduction of the measurement distance, the direction Z of probe, the increase of the frequency of control of serial chopper.