Real‐time control of shunt active power filter under distorted grid voltage and unbalanced load condition using self‐tuning filter

Abstract

Abstract-In this study, an alternative control method is proposed to improve the harmonic suppression efficiency of the active power filter in a distorted and unbalanced power system to

A Refined Self-Tuning Filter-Based Instantaneous Power Theory Algorithm for Indirect Current Controlled Three-Level Inverter-Based Shunt Active Power Filters under Non-sinusoidal Source Voltage Conditions

“…Under non-sinusoidal source voltage conditions, source voltage in α-β domain can actually be decomposed into dc and ac components as follows: In order to deal with non-sinusoidal source voltage conditions, a self-tuning filter (STF) is commonly applied to process the source voltage so that dc components of the source voltage can be extracted, serving as reference voltage to ensure in-phase operation of SAPF with the designated power system. In [7,40,42], the transfer function of STF for source voltage processing (after performing Laplace transformation) can be summarized as follows:…”

“…Like optimization algorithms, this algorithm is only evaluated under steady-state conditions. Another application of STF can be found in pq theory-based reference current generation algorithms, hereafter referred to as STF-based pq theory (STF-pq) algorithms [42]. In this case, the STF algorithm is applied to process the non-sinusoidal source voltage so that a purely sinusoidal reference voltage can be generated for proper synchronization purposes.…”

“…Nevertheless, as compared to SRF-based algorithm, STF-pq theory algorithm is much more preferable as it does not require additional PLL elements for synchronization purposes. Most importantly, the STF-pq theory algorithm is reported in [42] to work effectively under both steady-state and dynamic-state conditions.…”

“…In the context of STF-pq theory algorithms, for effective generation of reference currents, another STF is commonly implemented to process the transformed set of load currents [40,42]. However, the performance of STF is fully dependent on its fixed gain value which is normally obtained via an empirical approach.…”

“…To date, the conventional STF-pq theory algorithm still produces a non-sinusoidal reference current [7,40,42] and thus forces the SAPF to operate based on a direct current controlled (DCC) scheme [43][44][45]. From previous literature [45][46][47], it is revealed that the SAPF switching operation produces switching ripples which potentially degrade the THD value of the mitigated source current.…”