Development of laboratory prototype of a 12kVA digital shunt active filter

The paper reports the development of a laboratory prototype of a fully digital DSP controlled 12 kVA shunt active filter (ShAF) capable of compensating for non-linear, unbalanced load and reactive power. A fully digital controller is implemented for the reference generation and the current control purposes. The delay problem in digital current controller is overcome by application of a fast DSP, a compact controller and proper flow of control steps in the DSP software. A phase locked loop (PLL)-less software grid synchronization method has been proposed for the effective operation of the ShAF under the grid frequency variation. The source current THD has been improved from 15.8% to 4.45%. The control features, experimental setup, and results are presented in the paper.