In this paper an efficiency comparison between 3-phase shunt active filters derived from the 2-level VSC, the 3-level NPC, Active NPC (A-NPC) and the T-type VSC is presented. In order to address the loss distribution issue of the 3-level topologies, while keeping the efficiency of the system high, a space vector modulation scheme incorporating a special clamping of the phase is proposed. It is shown that 3-level active filters can have their losses well distributed over the chip dies, leading to only a small difference in their operating temperatures. Additionally, a semiconductor area based comparison is used to further evaluate the studied active filter systems. Finally, experimental results obtained with a 12kVAr/48kHz 3-level NPC based shunt active filter employing custom SiC power modules are presented in order to demonstrate the performance and feasibility of this solution.@en

In this article, the distortions caused by the power supplies employed in Electrostatic Precipitators (ESP) are investigated, and means for improving the line power quality are proposed. Multi-pulse and PWM rectifier topologies and other concepts including hybrid systems and active filters are evaluated in order to identify suitable systems for ESP applications. A comparison of the studied systems rated to 60 kW and fully designed employing commercial components is shown. The ESP systems efficiency, power density, current harmonic THD, among others features are used for the assessment. The loss calculations are extended to a variable chip area to allow a fair comparison between the studied systems. Finally, the VIENNA 6-switches rectifier and active filter concepts are chosen and experimental analyses are carried out, verifying the performance and feasibility of the proposed systems.@en

In this article the distortions caused by the pulsed operation of a group of power supplies (PS) feeding an Electrostatic Precipitator (ESP) are investigated, and means for improving the line quality are proposed. In order to reduce the Total Harmonic Distortions (THD) of the line current and also improve the loading balance between the phases, the pulses of the individual power supplies are scheduled and controlled together, so that the power consumption becomes more continuous. The proposed system optimization is experimentally verified with two commercially available ESP supplies, each having power capabilities of 120kW. The study shows the advantages of the pulses scheduling strategy namely reduction of both reactive power consumption and line current peaks; better current THD; better power balance among mains phases; and better utilization of mains components.@en

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.

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