Low-cost resolver-to-DC converter

Tongcharoen, Jakkapun; Petchmaneelumka, Wandee; Riewruja, Vanchai

doi:10.1109/iccas.2015.7364630

Cited by 7 publications

(3 citation statements)

References 5 publications

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“…Techniques that use a peakamplitude finder to overcome the disadvantage of simple synchronous demodulators have recently been proposed. (16,(20)(21) These techniques have a fast response, high accuracy, and low cost. Unfortunately, the transfer characteristic of the displacement signal provides a narrow linear operating range for the LVDT core moved in the full-stroke range.…”

Section: Introductionmentioning

confidence: 99%

Extension of Linear Operating Range for Linear Variable Differential Transformer Using Its Inverse Transfer Characteristic

Petchmaneelumka¹,

Songsuwankit²,

Rerkratn³

et al. 2023

Sensors and Materials

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An analog circuit technique to realize an inverse transfer characteristic of a linear variable differential transformer (LVDT) is presented in this paper. Practically, the structure of the LVDT causes a narrow linear operating range compared with its full stroke range. However, a large linear operating range requires a huge structure for the LVDT, making it unsuitable for a small or compact measurement system. The proposed technique can be used in a commercial LVDT to extend the linear operating range to its full stroke range. The technique utilizes an inherent behavior of an operational transconductance amplifier (OTA) to emulate the LVDT transfer characteristic. The LVDT transfer characteristic generated by the OTA is used as a feedback path of the inverting amplifier formed by an operational amplifier (opamp) to realize the inverse transfer characteristic. The residual error due to the OTA behavior is very small and can be neglected without adversely affecting the performance of the proposed technique. All devices used in the proposed scheme are commercially available. The attractive features of the proposed technique are its simple configuration, small size, low cost, and high accuracy. The performance of the proposed technique is discussed in detail and confirmed by its experimental implementation. Measurement results demonstrate that the linear operating range of the commercial LVDT used in this study can be extended by a factor of more than 2.4, and a fullscale percentage error of about 0.068% was obtained.

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Section: Introductionmentioning

confidence: 99%

Extension of Linear Operating Range for Linear Variable Differential Transformer Using Its Inverse Transfer Characteristic

Petchmaneelumka¹,

Songsuwankit²,

Rerkratn³

et al. 2023

Sensors and Materials

View full text Add to dashboard Cite

show abstract

“…The disadvantage of the simple demodulator is that the large response time and phase shift of the low-pass filter or integrator degrade the accuracy of the demodulated signal. An alternative demodulation technique using a peak-amplitude finder was proposed to overcome the disadvantage mentioned above [ 18 , 19 , 20 ]. This technique exhibits a simple configuration, fast response, and high accuracy.…”

Section: Introductionmentioning

confidence: 99%

Linear-Range Extension for Linear Variable Differential Transformer Using Hyperbolic Sine Function

Rerkratn

Tongcharoen

Petchmaneelumka

et al. 2022

Sensors

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In this paper, a circuit technique to extend the measuring range of a linear variable differential transformer (LVDT) is proposed. The transfer characteristic of the LVDT contains the odd function form of the cubic polynomial. Therefore, the measuring range of a commercial LVDT is linear in a narrow range compared to its physical dimensions. The wide measuring range of the LVDT requires a large structure of the LVDT, which increases the scale and the cost of the measurement system. The measuring range of the LVDT can be linearly extended to the maximum of the stroke range using the proposed technique. The realization of the proposed technique is based on the use of the hyperbolic sine (sinh) function of the electronic circuit building block, named the class AB bipolar amplifier. The class AB bipolar amplifier can be obtained by the current feedback operational amplifier (CFOA). The circuit of the proposed technique requires two CFOAs and an operational transconductance amplifier (OTA) as the active devices and all devices used in the proposed technique to synthesize the sinh function are commercially available. The proposed technique exhibits an ability to compensate for the nonlinear characteristic of the LVDT without digital components. The proposed technique is attractive in terms of its simple circuit configuration, small size, and low cost. The linear range extension of the LVDT used in this paper is significantly increased with a maximum error of about 18.3 μm of 6.2 mm at the full stroke range or the full-scale percentage error of about 0.295%. The results indicate that the proposed technique provides excellent performance to extend the measuring range of the LVDT without modifying the LVDT structure.

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“…However, the response time and accuracy of these demodulators deteriorate due to the large time constant and phase shift caused by the dominant pole of the low-pass filter and integrator. To overcome these disadvantages, an alternative technique using a peak-amplitude finder was introduced [ 3 , 11 , 12 ]. This technique provides a simple configuration and rapid response.…”

Section: Introductionmentioning

confidence: 99%

A Temperature-Compensation Technique for Improving Resolver Accuracy

Petchmaneelumka

Riewruja

Songsuwankit

et al. 2021

Sensors

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Variation in the ambient temperature deteriorates the accuracy of a resolver. In this paper, a temperature-compensation technique is introduced to improve resolver accuracy. The ambient temperature causes deviations in the resolver signal; therefore, the disturbed signal is investigated through the change in current in the primary winding of the resolver. For the proposed technique, the primary winding of the resolver is driven by a class-AB output stage of an operational amplifier (opamp), where the primary winding current forms part of the supply current of the opamp. The opamp supply-current sensing technique is used to extract the primary winding current. The error of the resolver signal due to temperature variations is directly evaluated from the supply current of the opamp. Therefore, the proposed technique does not require a temperature-sensitive device. Using the proposed technique, the error of the resolver signal when the ambient temperature increases to 70 °C can be minimized from 1.463% without temperature compensation to 0.017% with temperature compensation. The performance of the proposed technique is discussed in detail and is confirmed by experimental implementation using commercial devices. The results show that the proposed circuit can compensate for wide variations in ambient temperature.

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Low-cost resolver-to-DC converter

Cited by 7 publications

References 5 publications

Extension of Linear Operating Range for Linear Variable Differential Transformer Using Its Inverse Transfer Characteristic

Extension of Linear Operating Range for Linear Variable Differential Transformer Using Its Inverse Transfer Characteristic

Linear-Range Extension for Linear Variable Differential Transformer Using Hyperbolic Sine Function

A Temperature-Compensation Technique for Improving Resolver Accuracy

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