scholarly journals Accuracy Improvement of Stator Inductance Identification Method Based on Low-Frequency Current Injection for Three-Level NPC Inverter-Fed IM Drives in Locked-Rotor Standstill Condition

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 488
Author(s):  
Yerganat Khojakhan ◽  
Kyoung-Min Choo ◽  
Junsin Yi ◽  
Chung-Yuen Won
Keyword(s):  
Induction Motor ◽  
Low Frequency ◽  
Current Injection ◽  
Heavy Load ◽  
Injection Test ◽  
Low Speed ◽  
Injection Speed ◽  
Speed Test ◽  
Identification Method ◽  
Drive Systems

In this paper, a stator inductance identification process is proposed. The process is based on a three-level neutral-point-clamped (NPC) inverter-fed induction motor (IM) drive with a standstill condition. Previously, a low-speed alternating current (AC) injection test for stator inductance identification was proposed to overcome practical problems in conventional identification methods for three-level NPC inverter-based IM drives. However, the low-speed AC injection test-based identification method has some problems if a heavy load or mechanical brake is connected, as these can forcibly bring the rotor to a standstill during parameter identification. Since this low-speed testing-based identification assumes the motor torque is considerably lower in low-speed operations, some inaccuracy is inevitable in this kind of standstill condition. In this paper, the proposed current injection speed generator is based on the previously studied low-speed test-based stator inductance identification method, but the proposed approach gives more accurate estimates under the aforementioned standstill conditions. The proposed method regulates the speed for sinusoidal low-frequency AC injection on the basis of the instantaneous reactive and air-gap active power ratio. This proposed stator inductance identification method is more accurate than conventional fixed low-frequency AC signal injection identification method for three-level NPC inverter-fed IM drive systems with a locked-rotor standstill condition. The proposed method’s accuracy and reliability were verified by simulation and experiment using an 18.5 kW induction motor.

scholarly journals Stator Inductance Identification Based on Low-Speed Tests for Three-Level NPC Inverter-Fed Induction Motor Drives

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 183 ◽  
Author(s):  
Yerganat Khojakhan ◽  
Kyoung-Min Choo ◽  
Chung-Yuen Won
Keyword(s):  
Induction Motor ◽  
Reactive Power ◽  
Low Frequency ◽  
Test Drive ◽  
Identification Process ◽  
Low Speed ◽  
Speed Test ◽  
Simulation And Experiment ◽  
Sinusoidal Current ◽  
Stator Flux

This paper proposes a stator inductance identification process for three-level neutral point clamped (NPC), inverter-fed Induction Motor (IM) drives based on a low-speed test drive. Conventionally, the stator inductance of an IM is identified by methods based on standstill or rotational tests. Since conventional standstill test-based methods have several practical problems when used with three-level inverters because of their nonlinearity, an identification method based on rotational tests is superior in such applications. However, conventional rotational tests cause unintended behavior because of the high speeds used during the test. In the proposed stator inductance identification process, the stator inductance is identified based on a low-speed test drive. In the proposed method, the stator flux is estimated using the instantaneous reactive power of the IM during low-frequency sinusoidal current excitation, and the stator inductance is then identified based upon this. Therefore, the proposed identification process is safer than conventional approaches, as it uses only a low-speed test. The accuracy and reliability of this method are verified by simulation and experiment using three motors with different rated voltage and power.

The Feature Extraction Method of Gear Magnetic Memory Signal

2013 ◽  
Vol 819 ◽  
pp. 206-211
Author(s):  
Yong Gang Xu ◽  
Zhi Cong Xie ◽  
Lin Li Cui ◽  
Jing Wang
Keyword(s):  
Gear Tooth ◽  
Low Frequency ◽  
Magnetic Memory ◽  
Magnetic Signal ◽  
Heavy Load ◽  
Low Speed ◽  
Feature Extraction Method ◽  
Test Technology ◽  
Time Scale Decomposition ◽  
Memory Signals

Magnetic memory test technology is a new nondestructive testing technique, which is able to detect of the stress concentration area and potential fault of low speed and heavy load gear. Because the magnetic memory signals are easy to be disturbed by various sources of noises, a new method based on the intrinsic time-scale decomposition (ITD) is proposed to achieve the extraction of magnetic memory signal. Firstly, the magnetic memory signals are decomposed into several proper rotation components (PRC) and a trend component by ITD. Then reconstruct the first four order PRCs to eliminate the low frequency cyclic composition of magnetic memory signal and magnetic noise. Finally, the magnetic signal strengths of each gear tooth root are extracted using cycle average and local statistic method. The results of Experiments show that the method is suitable to pick up effective ingredients of signal to extract signal feature and has important application value in potential fault diagnosis of low speed and heavy load gearbox.

High Speed Experimental Study of Friction Induced Vibration in Disc Brakes

2012 ◽  
Vol 229-231 ◽  
pp. 747-749
Author(s):  
K. Magaswaran ◽  
A.S. Phuman Singh ◽  
Muhammad Zahir Hassan
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Low Frequency ◽  
Low Speed ◽  
Speed Test ◽  
Disc Brakes ◽  
Stop Condition ◽  
Friction Induced Vibration ◽  
Speed Characteristic

Brake dynamic groan noise which is a low frequency phenomena associated with brake stop condition or slow brake release. This phenomenon said to be a friction-speed characteristic and commonly associated with low speed events. Thus a high speed test regarding this phenomenon is done. In conjunction with speed, pressure relation is also tested. Analysis of groan occurrence in relation of the speed and pressure is performed. The pressure relation to this event is expected to widen the study of this phenomenon which currently confined to stick and slip motions.

Analyzed on the Lubrication Characteristics Orthogonal Test of the Low Speed and Heavy Load Equipment

2014 ◽  
Vol 900 ◽  
pp. 763-766
Author(s):  
Si Yu Chen ◽  
Chun Shan Liu ◽  
Ya Qin Li ◽  
Xiao Xia Li ◽  
Jun Fa Wang
Keyword(s):  
Dynamic Performance ◽  
High Load ◽  
Heavy Load ◽  
Factors Affecting ◽  
Low Speed ◽  
Software Optimization ◽  
Speed Test ◽  
Low Load ◽  
Traction Coefficient ◽  
Lubrication Characteristics

The traction characteristics of lubricant is one of the important parameters of the dynamic performance of bearings design .This paper chose three significant factors affecting the traction coefficient：temperature、load and rotate speed. Test results showed that the traction coefficient under the high load is significantly higher than under low load from room temperature to 135 °C. After more than 135 °C, the traction coefficient under the low load is higher than under the high load. It illustrated that the grease was sensitive to temperature but it reflected high temperature stable performance.The optimum conditions were obtained by Design-Expert software optimization : temperature for 235°C、load for 2800.00N、rotate speed for 183.17r/min and in this time the traction coefficient is at 0.547 in this test. It shown that the grease fitted the low speed and heavy load equipment.

Low-frequency signal-demodulation-based sensorless technique for induction motor drives at low speed

2006 ◽  
Vol 53 (1) ◽  
pp. 207-215 ◽  
Author(s):  
A. Consoli ◽  
G. Scarcella ◽  
G. Bottiglieri ◽  
G. Scelba ◽  
A. Testa ◽  
...  
Keyword(s):  
Induction Motor ◽  
Low Frequency ◽  
Motor Drives ◽  
Induction Motor Drives ◽  
Frequency Signal ◽  
Low Speed ◽  
Signal Demodulation
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