Common mode and EMI concerns in PWM inverters supplying general loads

Pulse width modulated (PWM) inverters are increasingly present on the power system. This paper discusses the generation of voltage in the PWM frequency range by the inverter, particularly for both the common mode signals. A model is developed to study the propagation of these frequencies through the input and output leads of the inverter. The paper provides a discussion of the various techniques for reducing the inverter output in this frequency range, and it is shown that both common mode and differential mode noise reduction should be considered. The need for specification of the common mode output voltage wave for many of these applications is shown