Automatic Testing of the EMI Due to the Switching Frequency of the PWM Signal

An autotuning system, which takes into account the self-compatibility of power converters, is proposed in this paper. It is based on a startup routine and a self-disturbance evaluation board, which selects the optimal switching frequencies for the power converter in order to decrease the internal disturbances in terms of electromagnetic interference between the power section and the control one. The entire test and tuning system does not require any field or current sensor but just digital comparators and counters. This configuration allows achieving a robust and low-cost autotuning system for internal compatibility of power converters.