Measurement and analysis of EMF around pulsed power supplies

The pulse current generated by pulsed power supply could be several hundred thousand amperes, which could produce great interference to the electronic apparatus and other modules of the power supply. Thereby, the measurement of spatial and temporal distributions of radiated electromagnetic fields could be useful. Two supplies with spark gap (SG) switches and silicon controlled rectifier (SCR) switches are focused, and both use capacitors to store energy. Several B-dot probes, D-dot probes and a digital oscilloscope, with enough sampling rate and memory depth, are used to measure the magnetic and electric fields. The result shows that the spectrum of magnetic fields around SG switches can reach 10 MHz, while that around SCR switches is less than 1 MHz. The latter would be better for the system electromagnetic compatibility.