Simple model of metal oxide varistor for Pspice Simulation

Metal oxide varistors (MOVs) are commonly used to suppress transients in many applications, such as industrial process measurement and control instrumentation, when exposed to electromagnetic interference. Varistors symmetrical, sharp breakdown characteristics enable them to provide transient suppression performance. A simple model of MOVs for Pspice simulation is proposed in this paper. The comparison between measured characteristics of MOVs and the proposed model results in a good approach for the active zone of the device. Besides, the comparison with other models shows that: 1) this one solves problems of numerical convergence and 2) there is an important reduction in the number of model parameters to be set beforehand.