Comparison of concepts for improving the line power quality of Electrostatic Precipitator systems

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 power quality are proposed. In order to reduce the Total Harmonic Distortions (THD) of the line current and also to improve the loading balance between the grid phases for pulsed operation, the pulses of the individual power supplies are scheduled and controlled together, so that the power consumption becomes more continuous. As an alternative to the three-phase diode bridge rectifiers, which are used as front-end converters in modern ESP power supplies, multi-pulse and PWM rectifier topologies described in the literature and other concepts including hybrid systems as well as active filters are evaluated in order to identify a suitable topology for ESP applications. A comparison of the proposed ESP systems, considering the implementation complexity, power semiconductor losses, circuit elements stresses, etc. is presented.