Using SMPS technology to energize electrostatic precipitators enhances both  total collection efficiency and fine particulate collection. This is achieved mainly due to the almost ripple-free high voltage signal provided by a high frequency power supply, where a traditional Transformer/Rectifier (T/R) will have a ripple similar to the low frequency - 50/60 hz - of the mains input. 

A direct comparision of voltage levels as shown below, shows that SMPS energisation provides a higher average voltage and thus more power to the ESP.