Frequency response function measurement utilizing radial excitation force generated by permanent magnet synchronous motor

Tsunoda, Wataru; Chibá, Akira; Shinshi, Tadahiko

doi:10.1016/j.mechatronics.2019.05.007

Cited by 8 publications

(4 citation statements)

References 13 publications

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“…The main tasks for NARX model identification include common model structure identification, coefficient calculation, and model validation. Motivated by the system identification method for the common model structure [36] and inspired by the feature extraction method based on the information obtained through frequency sweep [37], this paper aims to develop a new frequency sweep modeling method in the time domain that can be used to select the most significant model terms corresponding to all the rotating speed of the rotor system. Then, the speed is introduced into the coefficients of the common model structure to predict the output of the underlying system just based on the operating speed.…”

Section: The Frequency Sweep Modeling Methods In the Time Domainmentioning

confidence: 99%

Frequency Sweep Modeling Method for the Rotor-Bearing System in Time Domain Based on Data-Driven Model

Jin

Zhu

et al. 2022

Processes

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In practice, the modeling and analysis of nonlinear rotor-bearing systems are difficult due to the nonlinearity and complexity. In the previous studies, finite element simulation and mathematical modeling methods are mostly adopted to conduct the analysis. However, due to the time-consuming problem in finite element simulation and the lack of sufficient prior knowledge in mathematical modeling, the traditional method is difficult to establish the representation model. In order to overcome this issue, in this study, a data-driven model referred to as the NARX (Nonlinear Auto-Regressive with exogenous inputs) model is introduced to conduct the modeling and analysis of the rotor-bearing system. The identification of the NARX model requires random excitation as the system input, while the input signal of the rotor system is harmonics. Therefore, a time-domain frequency sweep modeling method is proposed in this paper by introducing the rotating speed into the coefficients function expression of the NARX model, the system output can be predicted according to the given speed. Moreover, the representation model of the rotor-bearing system obtained by using the proposed method is validated under different rotating speeds, the results show the applicability of the proposed modeling approach. Finally, an experimental case of the rotor-bearing test rig is demonstrated to show the application in practice. Both the numerical and experimental studies illustrate the applicability of the proposed modeling method, which provides a reliable model for dynamic analysis and fault diagnosis of the rotor-bearing system.

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Section: The Frequency Sweep Modeling Methods In the Time Domainmentioning

confidence: 99%

Frequency Sweep Modeling Method for the Rotor-Bearing System in Time Domain Based on Data-Driven Model

Jin

Zhu

et al. 2022

Processes

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“…A compact and simple test rig with a BELM was used as shown in Fig. 7 (Tsunoda et al, 2019a(Tsunoda et al, , 2019b. The rotor is supported by two circular oil-film bearings and rotated by a consequent-pole-type BELM (Chiba et al 2005) placed at the midpoint of the rotor-shaft.…”

Section: Experimental Test Rig 41 Test Rig With a Bearingless Motormentioning

confidence: 99%

“…Rotor centricity is mainly divided into static and dynamic eccentricity. In previous research (Tsunoda et al, 2018(Tsunoda et al, , 2019b, we discussed measurement of the FRF of a rotor system with dynamic eccentricity. The effect of the eccentricity and the rotational speed on the FRF was not evaluated.…”

Section: Introductionmentioning

confidence: 99%

Frequency response function measurement of a rotor system utilizing electromagnetic excitation by a built-in motor

Ren

Tsunoda

Han

et al. 2020

JAMDSM

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In this paper, we propose a practical method for evaluating the robustness and stability of rotating machines. This entails using electromagnetic excitation and measuring the frequency response functions (FRFs) of the rotor system during rotation. The difficulty of applying excitation can be solved by utilizing a built-in motor with static eccentricity and adding a sinusoidal sweep d-axis current to the motor. A test rig with a bearingless motor (BELM) was used to verify the validity of the proposed method. A consequent-pole-type BELM is a combination of a consequent-pole-type motor and a radial magnetic bearing, in which both the motor and the suspension windings are arranged in one stator core of the BELM. The center of the motor is defined by the zero-power controller and the static eccentricity is determined by the suspension control system. The FRFs measured utilizing the electromagnetic excitation generated by the motor windings was compared with reference FRFs measured utilizing the suspension windings. The natural frequencies and damping ratios were determined from the two different FRFs. The difference between the identified natural frequencies and the difference between the damping ratios for the two different FRFs were calculated. The effectiveness of measuring the dynamic characteristics of the rotor system under various rotational conditions, such as the rotational speed and eccentricity, was clarified and the differences between the measurements obtained from the two different FRFs were generally less than 7.7%.

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“…In our previous research [17,18], the UMF was utilized as a radial excitation force. Excitation forces at different frequencies were realized by injecting a sweep frequency d-axis current into the motor windings.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the Dynamic Parameters of the Bearings in a Flexible Rotor System Utilizing Electromagnetic Excitation by a Built-In Motor

et al. 2021

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Estimation of the dynamic parameters of bearings is essential in order to be able to interpret the performance of rotating machinery. In this paper, we propose a method to estimate the dynamic parameters of the bearings in a flexible rotor system. By utilizing the electromagnetic excitation generated by a built-in PM motor and finite element (FE) modeling of the rotor, safe, low-cost, and real-time monitoring of the bearing dynamics can be achieved. The radial excitation force is generated by injecting an alternating d-axis current into the motor windings. The FE model of the rotor and the measured frequency responses at the motor and bearing locations are used to estimate the dynamic parameters of the bearings. To evaluate the feasibility of the proposed method, numerical simulation and experiments were carried out on a flexible rotor system combined with a bearingless motor (BELM) having both motor windings and suspension windings. The numerical simulation results show that the proposed algorithm can accurately estimate the dynamic parameters of the bearings. In the experiment, the estimates made when utilizing the excitation force generated by the motor windings are compared with the estimates made when utilizing the excitation force generated by the suspension windings. The results show that most of the stiffness and damping coefficients for the two experiments are in good agreement, within a maximum error of 8.92%. The errors for some coefficients are large because the base values of these coefficients are small in our test rig, so these coefficients are sensitive to deviations. The natural frequencies calculated from the dynamic parameters estimated from the two experiments are also in good agreement, within a maximum relative error of 3.04%. The proposed method is effective and feasible for turbomachines directly connected to motors, which is highly significant for field tests.

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Frequency response function measurement utilizing radial excitation force generated by permanent magnet synchronous motor

Cited by 8 publications

References 13 publications

Frequency Sweep Modeling Method for the Rotor-Bearing System in Time Domain Based on Data-Driven Model

Frequency Sweep Modeling Method for the Rotor-Bearing System in Time Domain Based on Data-Driven Model

Frequency response function measurement of a rotor system utilizing electromagnetic excitation by a built-in motor

Estimation of the Dynamic Parameters of the Bearings in a Flexible Rotor System Utilizing Electromagnetic Excitation by a Built-In Motor

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