Analysis of single-phase PLL with novel two-phase generator for grid-connected converters

Lale, Srđan; Lubura, Slobodan; Šoja, Milomir; Ikić, Marko

doi:10.1109/telfor.2011.6143645

Cited by 2 publications

(2 citation statements)

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“…The key component of single‐phase PLL‐SRF structure is two‐phase generator which produces two signals in quadrature v α and v β from single‐phase grid voltage which is usually distorted. Typically, it consists of second‐order filters described in [2, 5, 13, 15]. Transfer functions of these filters, in continuous time domain are given by

W_{α} false(s false) = \frac{ω s}{s^{2} + ω s + ω^{2}}

W_{β} false(s false) = \frac{ω^{2}}{s^{2} + ω s + ω^{2}}

Filter W α ( s ) is band‐pass and W β ( s ) is low‐pass filter, so both filters can successfully attenuate only high‐frequency noise and cannot reject induced DC offset if it appears in measured grid voltage.…”

Section: Novel Two‐phase Generator With DC Offset and Noise Rejectionmentioning

confidence: 99%

“…In [13] we proposed a single-phase PLL-SRF structure with novel two-phase generator which has capability to fully reject induced DC offset and noise. Our basic idea is modification of two-phase generator (1) and (2) and addition of the simple control loop in its structure in order to simultaneously make necessary phase shift and reject induced DC component and noise without adding any additional external filter.…”

Section: Introductionmentioning

confidence: 99%

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Single‐phase phase locked loop with DC offset and noise rejection for photovoltaic inverters

Lubura

Šoja

Lale

et al. 2014

IET Power Electronics

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Proper work of grid-connected converters requires an accurate detection of phase angle, frequency and amplitude of grid voltage. Phase locked loops (PLLs) based on synchronous reference frame theory can be used for estimation of these grid parameters. One of the issues that could appear during estimation of grid parameters is appearance of DC offset in measured grid voltage. This DC component (offset) is usually entered in PLL structure via measurement and A/D conversion process. Undesirable induced DC offset could appear as part of the reference sine current of photovoltaic inverters or other grid-connected converters. A lot of standards define allowed PV inverter's DC current injection in the grid. In this study, we propose an improved PLL structure with capability to fully reject DC offset and noise which could appear in measured input grid voltage. The key component of the proposed PLL is two-phase generator with a closed control loop for DC offset and noise rejection. Obtained simulation and experimental results show that the proposed PLL structure can solve important issues of presence of noise and DC offset in measured grid voltage. The proposed PLL structure shows excellent dynamical performances in conditions of fast changes of grid parameters.

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