Self-sensing for electromagnetic actuators. Part II: Position estimation

Ranft, E.O.; Schoor, George van; Rand, C.P. du

doi:10.1016/j.sna.2011.09.037

Cited by 18 publications

(9 citation statements)

References 3 publications

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“…Modulation self-sensing, regardless of the signal-processing algorithm, benefit from limiting the voltage duty cycle to ensure sufficient excitation ( i.e. , current ripple amplitude), thereby increasing system robustness [ 2 , 11 , 13 ]. The dynamic performance of an AMB utilizing DCM self-sensing is therefore comparable to that of AMBs employing other self-sensing approaches.…”

Section: Dcm Self-sensingmentioning

confidence: 99%

“…The sensitivity function evaluates the robustness of the AMB control for parameter variations and disturbance forces. However, established robustness indicators do not yet exist for self-sensing AMBs [ 11 , 19 ]. The analysis is performed according to ISO 14839-3, which documents the sensitivity analysis for AMBs with standard displacement sensors.…”

Section: Self-sensing Performance Evaluationmentioning

confidence: 99%

“…The main advantages of this approach are improved system robustness, uncoupled sensing information at high frequencies, and minimal additional hardware requirements. In the literature, a large part of research focuses on this solution for self-sensing AMBs [ 1 – 4 , 7 – 11 ].…”

Section: Introductionmentioning

confidence: 99%

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A Self-Sensing Active Magnetic Bearing Based on a Direct Current Measurement Approach

Niemann

Schoor

Rand

2013

Sensors

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Active magnetic bearings (AMBs) have become a key technology in various industrial applications. Self-sensing AMBs provide an integrated sensorless solution for position estimation, consolidating the sensing and actuating functions into a single electromagnetic transducer. The approach aims to reduce possible hardware failure points, production costs, and system complexity. Despite these advantages, self-sensing methods must address various technical challenges to maximize the performance thereof. This paper presents the direct current measurement (DCM) approach for self-sensing AMBs, denoting the direct measurement of the current ripple component. In AMB systems, switching power amplifiers (PAs) modulate the rotor position information onto the current waveform. Demodulation self-sensing techniques then use bandpass and lowpass filters to estimate the rotor position from the voltage and current signals. However, the additional phase-shift introduced by these filters results in lower stability margins. The DCM approach utilizes a novel PA switching method that directly measures the current ripple to obtain duty-cycle invariant position estimates. Demodulation filters are largely excluded to minimize additional phase-shift in the position estimates. Basic functionality and performance of the proposed self-sensing approach are demonstrated via a transient simulation model as well as a high current (10 A) experimental system. A digital implementation of amplitude modulation self-sensing serves as a comparative estimator.

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Section: Dcm Self-sensingmentioning

confidence: 99%

Section: Self-sensing Performance Evaluationmentioning

confidence: 99%

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A Self-Sensing Active Magnetic Bearing Based on a Direct Current Measurement Approach

Niemann

Schoor

Rand

2013

Sensors

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“…As the switching frequency is generally high, updating the rotor position at each switching cycle is difficult. Therefore, Ranft et al [ 41 ], Van Schoor et al [ 42 ] and Yu et al [ 43 ] and Li et al [ 44 ] suggested the reduction of the switching frequency or updating of the position every several cycles. Apparently, for self-sensing AMBs to adapt to high-speed rotary machines is challenging.…”

Section: Introductionmentioning

confidence: 99%

Synchronous Sampling-Based Direct Current Estimation Method for Self-Sensing Active Magnetic Bearings

Wang

et al. 2020

Sensors

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Active magnetic bearings (AMBs) commonly use pulse-width modulation to reduce analogous hardware and manufacturing costs, but they experience sensing process, sensing accuracy and stability problems. To address these issues, a synchronous sampling-based direct current estimation (SS-DCE) method is proposed herein with a bistate switching power amplifier. First—considering the reluctance evolution mechanism of AMBs—a coupling relation mathematical model between rotor displacement and voltage/current is presented to acquire the rotor position from the working coil current alone. Then—assuming that the switching current was an approximately triangular signal—a DCE for the rotor position was established based on the estimation inductance of the charging/discharging phase. Finally—to decrease the phase shift caused by the self-sensing filters and position estimation algorithms—the SS-DCE method was introduced to conduct precise position detection for rotors with high velocities. The simulation and experimental results indicated that the proposed method could improve the sensing accuracy and stability. Compared to other AMB position estimation methods, the simple linearity of the SS-DCE method was greatly improved and could be controlled below 4%. Evaluation using frequency response analysis showed that the SS-DCE method had excellent dynamic accuracy and could perform at a higher phase margin, especially for the uprising/landing transient state. Moreover, there was a phase margin of 158° at the natural frequency of 19.26 HZ, and the peak sensitivity in the 50–250 μm range reached 10.7 dB.

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“…As the PWM switching frequency is generally very high, the update of the rotor displacement estimation at each switching cycle may be difficult. (12,13) A method of estimating rotor displacement to address the above problem was proposed in 2020. (14) Two types of direct current estimator were introduced to analyze the current gradient information and reduce the overhead time of the estimation simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on Frequency Limitation of Sensing Signal for Maglev Rotor Displacement

Chen¹,

Wang²,

Lee³

2020

Sensors and Materials

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Self-sensing for electromagnetic actuators. Part II: Position estimation

Cited by 18 publications

References 3 publications

A Self-Sensing Active Magnetic Bearing Based on a Direct Current Measurement Approach

A Self-Sensing Active Magnetic Bearing Based on a Direct Current Measurement Approach

Synchronous Sampling-Based Direct Current Estimation Method for Self-Sensing Active Magnetic Bearings

Numerical Study on Frequency Limitation of Sensing Signal for Maglev Rotor Displacement

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