Frequency Estimation of Three-Phase Power System Using Weighted-Least-Square Algorithm and Adaptive FIR Filtering

This paper presents a novel Model Predictive Direct Power Control (MPDPC) approach for the pulse width modulation (PWM) rectifiers in the Aircraft Alternating Current Variable Frequency (ACVF) power system. The control performance of rectifiers may be largely affected by variations in the AC side impedance, especially for systems with limited power volume system. A novel idea for estimating the impedance variation based on the Bayesian estimation, using an algorithm embedded in MPDPC is presented in this paper. The input filter inductance and its equivalent series resistance (ESR) of PWM rectifiers are estimated in this algorithm by measuring the input current and input voltage in each cycle with the probability Bayesian estimation theory. This novel estimation method can overcome the shortcomings of traditional data based estimation methods such as least square estimation (LSE), which achieves poor estimation results with the small samples data set. In ACVF systems, the effect on the parameters estimation accuracy caused by the number of sampling points in one cycle is also analyzed in detail by simulation. The validity of this method is verified by the digital and Hard-in-loop simulation compared with other estimation methods such as the least square estimation method. The experimental testing results show that the proposed estimation algorithm can improve the robustness and the control performance of the MPDPC under the condition of the uncertainty of the AC side parameters of the three-phase PWM rectifiers in aircraft electrical power system.

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Cumulant-based adaptive FIR filtering for frequency estimation

10.1109/spect.1990.205583 ◽

1990 ◽

Author(s):

S.A. Dianat ◽

S. Venkataraman

Keyword(s):

Frequency Estimation ◽

Fir Filtering ◽

Adaptive Fir

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The Output Filter Identification of Three-Phase PWM Converter Using Weighted Least Square Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.734.877 ◽

2015 ◽

Vol 734 ◽

pp. 877-886

Author(s):

Yi Long Zhang ◽

Xue Guang Zhang

Keyword(s):

Control Strategies ◽

Least Square Method ◽

Operating Conditions ◽

Least Square ◽

Accurate Estimation ◽

Pwm Converter ◽

Weighted Least Square ◽

Three Phase ◽

Mathematical Techniques ◽

Output Filter

This paper proposed the Weighted Least Square method (WLS method) to identify the output filter of three-phase PWM converter, which incorporates the signal processing as well as mathematical techniques into conventional Least Square method. It sets different weights to different measurements according to the phase where it locates, based on the discovery of the correlation between accuracy and phase of current. The algorithm is tested in both simulation and experimental environment, and the results validate that proposed method gives accurate estimation in steady state, and can response within 10ms in when grid voltage drops. This method can work under both balanced and unbalanced operating conditions, therefore provides a powerful tool for various control strategies to better understand the operating conditions. Compared with the invasive method, which intentionally inject a series of white noise in the system, proposed WLS method does not bring any turbulence, while compared with conventional Least Square method, it possesses better stability as well as higher accuracy.

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