An improved three-level shunt active filter

Abstract

Abstract:A shunt active filter is capable of removing harmonic currents from the supply of commercial and industrial sites. This paper presents a novel method for generating the compensating current signal for an active filter that uses a three-level inverter to provide a fast transient response. It is shown that the active filter must be positioned downstream of the power factor correction capacitors for stable operation. A new compensating current technique, based on sinusoidal subtraction, together with the faster response of the three-level inverter produces a shunt active filter system that has superior performance compared to traditional two level systems.

Simulation a shunt active power filter using MATLAB/Simulink

“…A shunt active filter is capable of removing harmonics from the supply of commercial and industrial sites. Simon Round and friends use the new technique based on sinusoidal subtraction by using active filter to make an inverter which is more responsive to the harmonics [4].…”

Enhancing the stability of active harmonic filter using artificial neural network‐based current control scheme

“…Various solutions are reported in the literature for addressing the aforementioned instability problem [14, 16–32]. In [16–22], it has been reported that the instability problem can be avoided by repositioning the PFC capacitors at a point which is upstream to the point of sensing of the load current. By employing this scheme it is ensured that the current drawn by the PFC capacitors does not get included in the feedback path of the harmonic compensation loop.…”

Enhancing the stability of AHF

“…The above two classification criteria broadly divide the current control strategies into following four harmonic compensation schemes: (a) THC with direct current control [34]. (b) THC with indirect current control [25].…”

“…It has been reported in the literature that irrespective of the type of the current control scheme being employed for an AHF, the presence of PFC capacitors affects the operational behaviour of the AHF [34–58]. The operation of AHF can become unstable while compensating certain higher‐order harmonic components.…”

“…It can be intuitively inferred that, as the PFC capacitors act as a harmonic sink for certain higher‐order harmonic frequencies, the AHF can become unstable while compensating those harmonic frequencies. To overcome this problem, it has been suggested in the literature, to place the PFC capacitors ‘upstream’ to the current sensing point of the AHF [34], which means, the current flowing through the PFC capacitor has to be excluded while sensing the load current. However, it may not be possible to physically obtain such a current sensing point in a radial network similar to the one depicted in Fig.…”