Analysis of Phase Locked Loop (PLL) influence on DQ impedance measurement in three-phase AC systems

Shen, Z. John; Jaksic, Marko; Zhou, Bo; Mattavelli, Paolo; Boroyevich, Dushan; Verhulst, J.; Belkhayat, M.

doi:10.1109/apec.2013.6520326

Cited by 29 publications

(34 citation statements)

References 8 publications

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“…The perturbations are introduced at the PCC to build nine full equations based on a 3 × 3 impedance matrix for both the source side and the load side. A single perturbation can generate only three equations (for both the source and load side) [45]. At least three perturbations are introduced to build full 3 × 3 impedance matrices for the source and the load side.…”

Section: Mathematical Modeling Of the Impedances At The Pccmentioning

confidence: 99%

Small Signal Stability of a Balanced Three-Phase AC Microgrid Using Harmonic Linearization: Parametric-Based Analysis

2018

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The growth of power-electronic-based components is inescapable in future distribution grids (DGs). The introduction of these non-linear components poses many challenges, not only in terms of power quality, but also in terms of stability. These challenges become more acute when active loads are behaving as generators and power is flowing in reverse direction. The frequency-domain-based impedance modeling methods are preferred for small signal stability analysis (SSSA) of DGs involving such non-linear components. The harmonic linearization method can be used for impedance estimation, and afterwards, the Nyquist stability criterion can be used for stability analysis. In this paper, a parametric-based stability analysis of grid-connected active loads at the point of common coupling (PCC) is done by changing the parallel clustering distance and size of active loads. The results verify a positive impact on the stability of increasing parallel clustering and distance from the PCC and a negative impact of increasing the size of individual active loads.

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Section: Mathematical Modeling Of the Impedances At The Pccmentioning

confidence: 99%

Small Signal Stability of a Balanced Three-Phase AC Microgrid Using Harmonic Linearization: Parametric-Based Analysis

2018

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“…Changes to the system frequency should not be allowed and the perturbation signal should not have a disturbing effect on the frequency. Therefore several publications also deal with the frequency behavior of the PLL-device [14], [15].…”

Section: State Of the Artmentioning

confidence: 99%

“…Both methods provide similar outcome and are used for time-domain simulations in [3] as well as for the experimental results in this paper. The small signal impedanceZ or the admittanceỸ is calculated by using the current and voltage in polar coordinates, expressed by (15). The superscripts () a and () θ denote magnitude and phase angle respectively.…”

Section: B Data Aquisition and Small Signal Filtering Softwarementioning

confidence: 99%

Small signal impedance measurement in droop controlled AC microgrids

John

Mendoza-Araya

Venkataramanan

2014

2014 IEEE Energy Conversion Congress and Exposition (ECCE)

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Stable operation of microgrids is highly influenced by characteristics of generators due to their small size and inertia and fast and variable dynamics. Recent work has shown that microgird stability can be determined by analysis of small signal impedances at the point of interconnection. The purpose of small signal impedance measurement is to verify the analytical models of single devices and to provide measured impedances where analytical models are not available, so that stability may be established. Small signal impedance measurement typically involves in-situ injection of currents or voltages superimposed upon the operating system. In droop-controlled microgrids, since the frequency is a function of the power demand, the injection has to be independent of the frequency. In this paper an injection approach is proposed using a three phase buck converter. Analytical models using dynamic phasors are compared to measurement results obtained in a laboratory microgrid. The injection method and the incremental phasor models of passive loads are verified and small signal impedance measurements of an islanded and grid-connected microgrid are obtained including a voltage source PWM converter.

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“…To overcome this drawback, PLL for the grid synchronization of the current control is directly used to provide the synchronization phase for the perturbation injection and impedance calculation [6], [7]. Since the control bandwidth of this PLL is relatively high, it may lead to large errors, especially in the low-frequency range [8]. In order to avoid the error introduced by the synchronization phase angle using PLL, a decoupled perturbation injection method was proposed in [9].…”

Section: Introductionmentioning

confidence: 99%

“…a few Hz, and the low-bandwidth PLL would take a long time to obtain the grid frequency and cannot track the system frequency variations accurately, which significantly influences the impedance measurement results. The influence of PLL dynamics on the accuracy of the impedance measurement results was analyzed and a correction method of the impedance measurement was proposed in [8]. However, the impedance error introduced by PLL cannot be eliminated at the frequency below the bandwidth of the PLL used for impedance calculation.…”

Section: Introductionmentioning

confidence: 99%

Impact of Synchronization Phase Dynamics on DQ Impedance Measurement

Gong

Yang

Wang

2018

2018 IEEE 19th Workshop on Control and Modeling for Power Electronics (COMPEL)

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Small-signal stability assessment of the threephase system can be performed using the measured impedances of the load and source. To obtain the dc steadystate operation point, the impedances are measured in the rotating dq-frame, and the phase angle is needed for the coordinate transformation used in both the perturbation injection and the impedance calculation. However, the phase estimation may introduce additional dynamics, affecting the accuracy of impedance measurement. This paper investigates the impact of phase synchronization dynamics on the measured impedance results. It is revealed that the phase variations in the perturbation injection has little effect on the measured impedance, while the phase dynamics introduced in the impedance calculation may have a significant impact. Based on impedance transformation, a new impedance calculation method is proposed, which can reduce the errors caused by the phase dynamics. Finally, the simulation and experiment results verify the accuracy of the analytical results and the effectiveness of the proposed method.

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Analysis of Phase Locked Loop (PLL) influence on DQ impedance measurement in three-phase AC systems

Cited by 29 publications

References 8 publications

Small Signal Stability of a Balanced Three-Phase AC Microgrid Using Harmonic Linearization: Parametric-Based Analysis

Small Signal Stability of a Balanced Three-Phase AC Microgrid Using Harmonic Linearization: Parametric-Based Analysis

Small signal impedance measurement in droop controlled AC microgrids

Impact of Synchronization Phase Dynamics on DQ Impedance Measurement

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