Susceptibility of Electrical Control Systems to Electromagnetic Disturbances

The susceptibility of electrical systems to electromagnetic disturbances is mostly specified in the frequency domain. Similarly, the efficiency of suppression techniques, such as filtering and shielding, is also presently specified in the frequency domain. As an appreciable part of the malfunctions (destructive and nondestructive) in control systems is caused by nonrepetitive transient type of electromagnetic disturbances, it is proposed that the susceptibility slhould additionally be specified in the time domain. This is particularly true for control systems containing semiconductor devices, because these devices operate on the principle of minimum clharge injection. Although a transient in the time domain can be mathematically converted into the frequency domain for the purpose of analysis, this procedure does not correspond to the physical situation and therefore does not give the true susceptibility of the system. Finally, several criteria are proposed for specifying the susceptibility of control systems to electromagnetic disturbances.