THE MULTI RESONANT POWER CONVERTER TOPOLOGY FOR SUPPLYING ELECTROSTATIC PRECIPITATORS ON THERMAL POWER PLANTS Slobodan N.Vukosavić*, Željko V.Despotović** and Nikola Popov* Scholl of Electrical Engineering, University of Belgrade, Serbia*, boban@etf.rs Mihajlo Pupin Institute, University of Belgrade, Serbia**, zeljko.despotovic@pupin.rs Abstract: The power management of electrostatic precipitators (ESP) significantly affect on the separation efficiency of fly ash and fine particles from smoke gases that through the funnel drainage into the atmosphere as a specific unwanted product of electric energy production on thermal power plants (TPP). In previous decades ESP in TPP were supplying by SCR controlled devices having a high degree of reliability, but with relatively low collection efficiency, hence requiring large effective surface of the collection plates and a large weight of steel construction. The collection and energy efficiency of the ESP can be increased by applying multiresonant high frequency high voltage (HFHV) power supply. This paper describe the HFHV power unit AR70/1000, topology, principles of operation, simulations and measurement results obtained during extensive experimental investigations on thermal power plants Key words: Electrostatic precipitators, thermal power plants, multiresonant topology, power supply, IGBT, DSP control 1. INTRODUCTION The power management method of electrostatic precipitators (ESP) significantly affect on the separation efficiency of fly ash and fine particles from smoke gases that through the funnel drainage into the atmosphere as a specific unwanted product of electric energy production[1]. The ESP power supply and controls are traditionally based on one pair of back-to-back connected thyristors T1 and T2, which alter the amplitude of the primary AC voltage (Fig.1.). The primary supply is usually single-phase, 400V, 50Hz. By changing the firing angle, the voltage is being changed in the range from 0 to 400 V and brought to the primary of the line frequency power high voltage transformer (HVT) whose secondary voltage reaches 45 kV to 90 kV. Fig.1. Single phase SCR rectifier for supplying of ESP.