scholarly journals Load angle estimation of synchronous generator

2020 ◽  
Vol 30 (30) ◽  
pp. 81-91
Author(s):  
Slavko Veinović ◽  
Žarko Janda ◽  
Đorđe Stojić ◽  
Jasna Dragosavac ◽  
Dušan Joksimović ◽  
...  
Keyword(s):  
Estimation Method ◽  
Systems Design ◽  
Sampling Technique ◽  
Synchronous Generator ◽  
Input Voltage ◽  
Discrete Fourier Transformation ◽  
Angle Estimation ◽  
Zero Crossing ◽  
Synchronous Sampling ◽  
Load Angle

In this paper a load angle estimation method of round rotor synchronous generator is presented, for load angle limiter in AVR systems design purpose. To get information of load angle, it is necessary to have values of the one terminal voltage, one phase current and q-axis reactance Xq. Mentioned values are acquired by synchronous sampling technique and processed by discrete Fourier transformation. The accuracy of presented method highly depends on quality of zero-crossing detection of the input voltage signal and on the calculation estimation of the fundamental frequency. This method is of reduced sensitivity to higher harmonics presence contence in voltages and current waveforms. Another advantage, when compared to other dq or ab based calculations estimations, is the necessity of use only two measurement channels. Drawback of described approach is lack of immunity to current asymmetry. However, a solution to overcome this problem is offered by introducing the additional measurements into the algorithm to extract the synchronous sampled direct components of all three phase currents.

scholarly journals Sliding Mode Observer-Based Load Angle Estimation for Salient-Pole Wound Rotor Synchronous Generators

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1609 ◽  
Author(s):  
Nikola Lopac ◽  
Neven Bulic ◽  
Niksa Vrkic
Keyword(s):  
Power System ◽  
Sliding Mode ◽  
Synchronous Generator ◽  
Absolute Error ◽  
Sliding Mode Observer ◽  
Adaptive Observer ◽  
System Stability ◽  
Angle Estimation ◽  
Salient Pole ◽  
Load Angle

Synchronous generator load angle is a fundamental quantity for power system stability assessment, with possible real-time applications in protection and excitation control systems. Commonly used methods of load angle determination require additional measuring equipment, while existing research on load angle estimation for wound rotor synchronous generator has been limited to the estimator based on the generator’s phasor diagram and estimators based on artificial neural networks. In this paper, a load angle estimator for salient-pole wound rotor synchronous generator, based on a simple sliding mode observer (SMO) which utilizes field current, stator voltages, and stator currents measurements, is proposed. The conventional SMO structure is improved with use of hyperbolic tangent sigmoid functions, implementation of the second order low-pass filters accompanied with corresponding phase delay compensation, and introduction of an adaptive observer gain proportional to the measured field current value. Several case studies conducted on a generator connected to a power system suggest that the proposed estimator provides an adequate accuracy during active and reactive power disturbances during stable generator operation, outperforming the classical phasor diagram-based estimator by reducing mean squared error by up to 14.10%, mean absolute error by up to 41.55%, and maximum absolute error by up to 8.81%.

Sensorless Angle Estimation Method for Brushed DC Motor using Impedance Variation by Contact Switching

2017 ◽  
Vol 137 (11) ◽  
pp. 827-836
Author(s):  
Yuki Saito ◽  
Kazuma Nakai ◽  
Hiromu Sekiguchi ◽  
Satoshi Fukushima ◽  
Takahiro Nozaki ◽  
...  
Keyword(s):  
Estimation Method ◽  
Dc Motor ◽  
Angle Estimation ◽  
Impedance Variation

scholarly journals Robust Directional Angle Estimation of Underwater Acoustic Sources Using a Marine Vehicle

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3062 ◽  
Author(s):  
Jinwoo Choi ◽  
Jeonghong Park ◽  
Yoongeon Lee ◽  
Jongdae Jung ◽  
Hyun-Taek Choi
Keyword(s):  
Source Localization ◽  
Angular Displacement ◽  
Estimation Method ◽  
Time Delay Estimation ◽  
Accurate Estimation ◽  
Acoustic Source ◽  
Angle Estimation ◽  
Underwater Acoustic ◽  
Acoustic Sources ◽  
Marine Vehicle

Acoustic source localization is used in many underwater applications. Acquiring an accurate directional angle for an acoustic source is crucial for source localization. To achieve this purpose, this paper presents a method for directional angle estimation of underwater acoustic sources using a marine vehicle. It is assumed that the vehicle is equipped with two hydrophones and that the acoustic source transmits a specific signal repeatedly. The proposed method provides a probabilistic model for time delay estimation. The probability is recursively updated by prediction and update steps. The prediction step performs a probability transition using the angular displacement of the marine vehicle. The predicted probability is updated using a generalized cross correlation function with a verification process using entropy measurement. The proposed method can provide a reliable and accurate estimation of the directional angles of underwater acoustic sources. Experimental results demonstrate good performance of the proposed probabilistic directional angle estimation method in both an inland water environment and a harbor environment.

scholarly journals A New Single-Phase Direct Frequency Controller Having Reduced Switching Count without Zero-Crossing Detector for Induction Heating System

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 430
Author(s):  
Naveed Ashraf ◽  
Tahir Izhar ◽  
Ghulam Abbas ◽  
Ahmed Bilal Awan ◽  
Ali S. Alghamdi ◽  
...  
Keyword(s):  
Induction Heating ◽  
Heating System ◽  
Input Voltage ◽  
Heating Process ◽  
Zero Crossing ◽  
Pulse Width Modulated ◽  
Controlled Switching ◽  
Compact Size ◽  
Frequency Magnetic Field ◽  
Frequency Controller

Induction heating (IH) is an environmentally friendly solution for heating and melting processes. The required high-frequency magnetic field is accomplished through frequency controllers. Direct frequency controllers (DFC) are preferred to dual converters as they have low conversion losses, compact size, and simple circuit arrangement due to low component count. Numerous frequency controllers with complex switching algorithms are employed in the induction heating process. They have a complicated circuit arrangement, and complex control as their switching sequences have to synchronize with source voltage that requires the zero-crossing detection of the input voltage. They also have a shoot-through problem and poor power quality. Therefore, this research proposes a novel frequency controller with a low count of six controlled switching devices without a zero-crossing detector (ZCD) having a simple control arrangement. The required switching signals are simply generated by using any pulse-width-modulated (PWM) generator. The performance of the proposed topology is verified through simulation results obtained using the MATLAB/Simulink environment and experimental setup.

scholarly journals Tensor-Based Angle Estimation Approach for Strictly Noncircular Sources with Unknown Mutual Coupling in Bistatic MIMO Radar

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2788 ◽  
Author(s):  
Yuehao Guo ◽  
Xianpeng Wang ◽  
Wensi Wang ◽  
Mengxing Huang ◽  
Chong Shen ◽  
...  
Keyword(s):  
Mutual Coupling ◽  
Multiple Input Multiple Output ◽  
Estimation Method ◽  
Direction Of Arrival ◽  
Doa Estimation ◽  
Mimo Radar ◽  
Angle Estimation ◽  
Estimation Performance ◽  
Direction Of Departure ◽  
Value Decomposition

In the paper, the estimation of joint direction-of-departure (DOD) and direction-of-arrival (DOA) for strictly noncircular targets in multiple-input multiple-output (MIMO) radar with unknown mutual coupling is considered, and a tensor-based angle estimation method is proposed. In the proposed method, making use of the banded symmetric Toeplitz structure of the mutual coupling matrix, the influence of the unknown mutual coupling is removed in the tensor domain. Then, a special enhancement tensor is formulated to capture both the noncircularity and inherent multidimensional structure of strictly noncircular signals. After that, the higher-order singular value decomposition (HOSVD) technology is applied for estimating the tensor-based signal subspace. Finally, the direction-of-departure (DOD) and direction-of-arrival (DOA) estimation is obtained by utilizing the rotational invariance technique. Due to the use of both noncircularity and multidimensional structure of the detected signal, the algorithm in this paper has better angle estimation performance than other subspace-based algorithms. The experiment results verify that the method proposed has better angle estimation performance.

Sign in / Sign up

Export Citation Format

Share Document