Stationary-frame generalized integrators for current control of active power filters with zero steady-state error for current harmonics of concern under unbalanced and distorted operating conditions

TLDR

The authors propose stationary‑frame generalized integrators for sinusoidal signals to enable zero‑steady‑state‑error current control of active power filters under unbalanced and distorted conditions. A proportional‑integral current controller employing these integrators, with digitally realized PI constants and computation‑delay compensation, is applied to the active power filter. The approach achieves zero steady‑state error for the targeted current harmonics with reduced computation, as confirmed by extensive tests on a 10‑kW prototype.

Abstract

The paper proposes the concepts of integrators for sinusoidal signals. A proportional-integral (PI) current controller using stationary-frame generalized integrators is applied for current control of active power filters. Zero steady-state error for the concerned current harmonics is realized, with reduced computation, under unbalanced utility or load conditions. Designing of the PI constants, digital realization of the generalized integrators, as well as compensation of the computation delay are studied. Extensive test results from a 10-kW prototype are demonstrated.