This work presents a design optimization procedure for Series Parallel Resonant Converters (LCC) employed in Electrostatic Precipitator (ESP) power supplies. The system parameters, such as resonant tank elements, are selected in order to reduce semiconductor losses when a typical ESP energization operation range is considered. Here, the sum of the power losses of the switches are predicted for a set of parameters by mathematical models of the LCC resonant converter, and also by loss characteristics of suitable commercially available IGBTs obtained from experimental analysis and datasheet values. The analysis comprises two different control strategies: the conventional Variable Frequency (VF) control and the Dual Control (DC). Finally, the circuit operation and design are verified with a 60kW charging capability LCC resonant converter test set-up. Both control strategies are analyzed by comparing semiconductor's losses for five commercial modules.