scholarly journals A Unified Method for Online Detection of Phase Variables and Symmetrical Components of Unbalanced Three-Phase Systems with Harmonic Distortion

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3243 ◽  
Author(s):  
Christoph M. Hackl ◽  
Markus Landerer

This paper presents a method for online detection of symmetrical components of arbitrarily distorted and biased three-phase input signals. This method is based on Second-Order Generalized Integrators (SOGIs), for which a new tuning based on a gradient search is presented to achieve the fastest possible estimation. Frequency estimation is achieved by a Frequency Locked Loop (FLL) with Gain Normalization (GN) for which an Output Saturation (OS) is applied; this OS guarantees stability of the overall system. Offset detection is implemented by a combination of High-Pass Filter (HPF) and HPF-Amplitude Phase Correction (APC); the HPF filters out any offset, where the APC reconstructs the original offset-free signal. An identical method (APC) can be used for the implemented Low-Pass Filter (LPF) used for noise filtering. The resulting estimates are then used for Harmonic Sequence Detection (HSD) of each harmonic. For the overall system, stability is proven. The estimation performances of the proposed overall system are verified by simulation results. The improvements in tuning and offset detection are compared to standard approaches.

2018 ◽  
Vol 18 (1) ◽  
pp. 35 ◽  
Author(s):  
Rofiatul Izah ◽  
Subiyanto Subiyanto ◽  
Dhidik Prastiyanto

Synchronous Reference Frame Phase Locked Loop (SRF PLL) has been widely used for synchronization three-phase grid-connected photovoltaic (PV) system. On the grid fault, SRF PLL distorted by negative sequence component and grid harmonic that caused an error in estimating parameter because of ripple and oscillation. This work combined SRF PLL with Dual Second Order Generalized Integrator (DSOGI) and filter to minimize ripple and minimize oscillation in the phase estimation and frequency estimation. DSOGI was used for filtering and obtaining the 90o shifted versions from the vαβ signals. These signals (vαβ) were generated from three phase grid voltage signal using Clarke transform. The vαβ signal was the inputs to the positive-sequence calculator (PSC). The positive-sequence vαβ was transformed to the dq synchronous reference frame and became an input to SRF-PLL to create the estimation frequency. This estimation frequency from SRF PLL was filtered by the low-pass filter to decrease grid harmonic. Moreover, the output of low-pass filter was a frequency adaptive. The performance of DSOGI PLL with filter is compared with DSOGI PLL, SRF PLL, and IEEE standard 1547(TM)-2003. The improvement of DSOGI PLL with filter gave better performances than DSOGI PLL and SRF PLLbecause it minimized ripples and oscillations in the phase and frequency estimations.


Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 734
Author(s):  
Karolis Kiela ◽  
Marijan Jurgo ◽  
Vytautas Macaitis ◽  
Romualdas Navickas

This article presents a wideband reconfigurable integrated low-pass filter (LPF) for 5G NR compatible software-defined radio (SDR) solutions. The filter uses Active-RC topology to achieve high linearity performance. Its bandwidth can be tuned from 2.5 MHz to 200 MHz, which corresponds to a tuning ratio of 92.8. The order of the filter can be changed between the 2nd, 4th, or 6th order; it has built-in process, voltage, and temperature (PVT) compensation with a tuning range of ±42%; and power management features for optimization of the filter performance across its entire range of bandwidth tuning. Across its entire order, bandwidth, and power configuration range, the filter achieves in-band input-referred third-order intercept point (IIP3) between 32.7 dBm and 45.8 dBm, spurious free dynamic range (SFDR) between 63.6 dB and 79.5 dB, 1 dB compression point (P1dB) between 9.9 dBm and 14.1 dBm, total harmonic distortion (THD) between −85.6 dB and −64.5 dB, noise figure (NF) between 25.9 dB and 31.8 dB and power dissipation between 1.19 mW and 73.4 mW. The LPF was designed and verified using 65 nm CMOS process; it occupies a 0.429 mm2 area of silicon and uses a 1.2 V supply.


2018 ◽  
Vol 65 (11) ◽  
pp. 9025-9029 ◽  
Author(s):  
Parag Kanjiya ◽  
Vinod Khadkikar ◽  
Mohamed Shawky El Moursi

2014 ◽  
Vol 609-610 ◽  
pp. 1072-1076
Author(s):  
Qiu Ye Lv ◽  
Chong He ◽  
Wen Jie Fan ◽  
Yu Feng Zhang ◽  
Xiao Wei Liu

In this Paper, a 4th-Order Low-Pass Gm-C Filter is Presented. for the Design of Operational Tranconductance Amplifier(OTA), it Adopts the Techniques of Current Division and Current Cancellation. these Techniques can Help to Achieve a Low Transconductance Value. for the Architecture of the 4th-Order Gm-C Filter, it Consists of Two Biquads. the Two Biquads are Cascade Connected. the Gm-C Low-Pass Filter has been Implemented under 0.5 μm CMOS Process Model. the Final Simulation Results Show the Cutoff Frequency of the Filter is 100Hz and the Stop-Band Attenuation is Larger than 60dB. the Power Consumption is Lower than 1mW and the Total Harmonic Distortion(THD) is -55dB.


2013 ◽  
Vol 575-576 ◽  
pp. 293-296
Author(s):  
Qun Min Yan

in order to solve the problem of three-phase static inverter output waveform distortion, detailed analyzed of the voltage distortion caused by the deadband effect and the resulting harmonic components. The control method is proposed to set the deadband time combining with the voltage compensation, while in order to improve the inverter output, the converter output to design a trap filter and a low pass filter cascaded filtering circuit. Simulated analysis the entire system though Saber, using the digital chip TMS320F2812 to achieve appropriate compensation strategies, simulation results and experimental results have all proved the effectiveness of the design method.


Author(s):  
Md. Imran Azim ◽  
S. M. Mohiuddin

<p>This paper portrays an approach of an analysis that provides information regarding the presence of harmonics at the inverter output terminal. It is certainly true that harmonics cause unbalance and excessive neutral currents, interference in nearby communication networks and disturbance to other consumers. More importantly, torque pulsations in electric motor drives are caused by them. Thus, the minimization of the harmonics contained in the output of a single phase current controlled inverter undergoing hysteresis modulation technique is important so as to get rid of these detrimental effects. A model of an LC low pass filter has been provided in this paper for harmonics reduction purpose, as it blocks the harmonics and passes approximately a sinusoidal output. Moreover, the paper contains the method of Fast Fourier Transform (FFT) for fulfilling the desire of understanding not only the fundamental component but also the harmonics component flawlessly. It has been found from the simulation that the Total Harmonic Distortion (THD) in ideal case is 0%. On the other contrary, during the presence of harmonics, it steeps to 41.415% that can be mitigated to 0.0092% by implementing an LC low pass filter in a precise manner.</p>


2013 ◽  
Vol 732-733 ◽  
pp. 1167-1170
Author(s):  
Xia Feng ◽  
Xiao Jian Zhong ◽  
Qun Wei Xu ◽  
Guo Zhu Chen

The DC-bus voltage control is critical for stable operation of the three-phase four-wire Active Power Filter. DC-bus stable voltage loop and balance voltage loop are established based on the small signal model. Considering the disadvantages of the traditional PI control, second-order low-pass filter is introduced into the proposed controller. Simulation and experimental results are conducted to validate the effectiveness of the proposed strategy.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Suneel K. Kommuri ◽  
Kalyana C. Veluvolu ◽  
M. Defoort ◽  
Yeng C. Soh

This paper presents a speed and position estimation method for the permanent magnet synchronous motor (PMSM) based on higher-order sliding mode (HOSM) observer. The back electromotive forces (EMFs) in the PMSM are treated as unknown inputs and are estimated with the HOSM observer without the need of low-pass filter and phase compensation modules. With the estimation of back EMFs, an accurate estimation of speed and rotor position can be obtained. Further, the proposed method completely eliminates chattering. Experimental results with a 26 W three-phase PMSM demonstrate the effectiveness of the proposed method.


2011 ◽  
Vol 291-294 ◽  
pp. 2620-2623
Author(s):  
Jun Min Zhang

In this paper, according to the base-adaptive detecting method of harmonic current for APF, there had contradiction between detecting accuracy and dynamic response. It had been proved that this system is a symmetrical notch-filter. Based on analysis above, this paper is proposed improved-adaptive detecting method. A low-pass filter has been in base-adaptive system. We first discussed the stability of improved system. Then theoretical analysis and simulation test shows the bandwidth had been reduced nearby reference frequency. Simulation had showed that the dynamic performance was in a period and the harmonic distortion rate was no more than 1.7%.


Author(s):  
Tiezhou Wu ◽  
An Wang ◽  
Yawen Xu

Abstract By using power electronic devices, photovoltaic grid-connected power generation may inject harmonics into the power system. As the photovoltaic grid-connected inverter has the same basic structure as the active power filter, so the unified control of the photovoltaic grid and active filtering can be achieved. When the current unified control system compensates harmonics of the grid side, it mainly uses ip-iq harmonic detection method, which is based on instantaneous reactive power theory. When the three-phase voltage is unbalanced, the method has a large voltage phase angle detection error and the signal of the low-pass filter tracking system is long, detection time delay and even failure occur. This paper proposes an improved fast harmonic detection method. When phase deviation or amplitude change occurs to the three-phase voltage, the positive and negative-sequence voltages are simultaneously park transformed. The negative-sequence component is filtered by the current average module to obtain the fundamental amount of the voltage, then the phase angle of the positive-sequence voltage is accurately calculated to improve the harmonic current detection accuracy. Through the study of the integral method, it is found that the least common multiple of each harmonic period can be used as the integral interval, and the integral value is also zero, so the detection delay time is reduced by replacing the low-pass filter with an integration module. The simulation results show that the proposed harmonic detection algorithm can accurately detect harmonics when the three-phase voltage is unbalanced, and about 0.057 s improve the harmonic detection speed compared with the commonly used ip-iq method.


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