A Simple Voltage Sensorless Active Damping Scheme for Three-Phase PWM Converters With an $LCL$ Filter

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Active three-phase pulsewidth-modulated rectifiers are connected to the grid by an inductance or an <formula formulatype="inline"><tex>$LCL$</tex> </formula> filter. Although an <formula formulatype="inline"><tex> $LCL$</tex> </formula> filter is more effective since it more efficiently attenuates the switching harmonics, it causes stability problems. To enable a stable operation, either a damping resistor or an active damping (AD) algorithm has to be used. However, while a damping resistor causes additional losses, an AD algorithm usually requires extra sensors. To avoid these disadvantages, this paper shows simulation and experimental results of a simple ac voltage sensorless AD solution that is suitable for industrial applications. </para>