• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.26-30
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• 1996

This paper proposes a novel method to reduce the torque ripple due to the non-ideality of the current sensing parts in vector-controlled inverter-fed PMSM(Permanent Magnet Synchronous Motor) drive systems. The motor output torque equations are derived in terms of their offset voltages and different voltage transducing gains. And the effects of phase current errors on motor torque are analyzed for both salient PMSM and non-salient PMSM. The proposed method can eliminate the torque ripple by nulling the offset voltages and setting the voltage transducing gains to the same value. To verify the proposed method, digital simulations are carried out for non-salient PMSM.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.138-145
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• 2015

In this paper, a novel static overmodulation scheme (OVM) for space-vector PWM (SVPWM) is proposed. The proposed static OVM scheme uses the concept of adding offset voltages in linear region as well as overmodulation region to fully utilize DC-link voltage. By employing zero sequence voltage injection, the proposed scheme reduces procedures for achieving SVPWM such as complicated gating time calculation. In addition, this paper proposes a stepwise discontinuous angle movement in high modulation region in order to reduce Total Harmonic Distortion (THD). The validity of the proposed scheme is verified through theoretical analysis and experimental results.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.327-328
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• 2016

This paper proposes the PLL algorithms with both the quadrature signal generator (QSG) and the positive-sequence calculator (PSC) in order to remove the effects of the three-phase grid voltage with dc offset voltages. The performances of the proposed method are verified with both the simulation result and the experimental result with 32-bit DSP.

• Journal of Auto-vehicle Safety Association
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• v.7 no.2
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• pp.39-43
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• 2015

NDIR (Non-dispersive infrared Rays) alcohol sensor has been prototyped and its temperature characteristics were measured. In order to design novel optical alcohol sensor, elliptical structures with one common foci were modeled and analyzed their optical properties. After analyzing elliptic optical structures, a prototype alcohol sensor module was tested according to the temperature variations from $-20^{\circ}C$ to $35^{\circ}C$. The offset voltages of alcohol sensor decreased from 1.1056 V at the temperature $-20^{\circ}C$ to 0.7339 V at $35^{\circ}C$. However, the highest sensitivity of alcohol sensor showed about $303{\mu}V/ppm$ at room temperature.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.3
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• pp.283-292
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• 2016

The performance of 4-switch 3-phase inverter(: FSTPI) which replace two switches of 6-switch 3-phase inverter(: SSTPI) is mainly affected by the compensator unbalanced voltages and output voltage control method. This paper proposes a DC offset current injection method to compensate the capacitor unbalanced voltages for FSTPI. A simplified SVPWM method which can be applied to FSTPI is also proposed. The validity of the proposed methods is verified by simulation and experiment using SPMSM.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.963-966
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• 1999

This Paper describes the design of high speed and low power comparator based on the feed forward bias control. Major building blocks of this comparator are composed of input offset canceling circuit and feed forward bias control circuit. The usual offset canceling circuit cancels the offset voltages by storing them in capacitors using MOS switches, The comparator of this paper employs the bias control circuit which generates bias signal from the input signal. The bias signal is applied to the capacitors and keeps the transfer of chares in the capacitors in the minimal amount, therefore making the comparator operate in stable condition and reduce decision time. The comparator in this form has very samll area and power dissipation. Maximum sampling rate is 200 Ms/sec. The comparator is designed in 0.65${\mu}{\textrm}{m}$ technology and the offset is less than 0.5㎷.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.365-373
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• 2015

The performance of 4-switch 3-phase inverter(FSTPI) is mainly affected by the unbalanced voltages between two capacitors which replace two switches of conventional 6-switch 3-phase inverter(SSTPI). This paper proposes a DC offset current injection method to compensate the capacitor voltage unbalance for FSTPI. A simplified SVPWM method which can be applied to FSTPI is also proposed. The validity of the proposed methods is verified by computer simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.280-286
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• 1998

This paper proposes a novel method to reduce the torque ripple due to the non-ideality of the current sensing parts in vector-controlled inverter-fed AC motor drive systems. For PMSM(Permanent Magnet Synchronous Motor), motor output torque equations are derived in terms of their offset voltages and different voltage transducing gains. And the effects of phase current errors on motor torque are analyzed for both salient PMSM and non-salient PMSM. The proposed method can eliminate the torque ripple by nulling the offset voltages and setting the voltage transducing gains to the same value. To verify the proposed method, digital simulations are carried out for non-salient PMSM.

• Journal of Power Electronics
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• v.15 no.2
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• pp.504-517
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• 2015

This paper presents a novel switching voltage model and an offset-based pulse width modulation (PWM) scheme for multilevel inverters with unbalanced DC sources. The switching voltage model under a DC voltage imbalance will be formulated in general form for multilevel neutral-point-clamped topologies. Analysis of the reference switching voltages from active and non-active switching voltage components in abc coordinates can enable voltage implementation for an unbalanced DC-source condition. Offset voltage is introduced as an indispensable variable in the switching voltage model for multilevel voltage-source inverters. The PWM performance is controlled through the design of two offset components in a subsequence. One main offset may refer to the common mode voltage, and the other offset restricts its effect on the quality of PWM control in related DC levels. The PWM quality can be improved as the switching loss is reduced in a discontinuous PWM mode by setting the local offset, which is related to the load currents. The validity of the proposed algorithm is verified by experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.86.3-86
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• 2001

Hall effect sensor using 7um, 1.7 ohm-cm or 10um, 3.5 ohm-cm Bipolar process was successfully developed. The Hall sensor consists of various patterns, such as regular shapes, rectangles, diamond, hexagon and cross shapes to optimize offset voltage and sensitivity for proper applications. In order to measure offset voltage in chip scale the Agilent company´s 4156C and Nano-Voltage Meter were used and the best structure in offset voltage was finally selected by using ceramic package. The patterns appear to be the quadri-rectangular patterns entirely and three-parallelogram patterns. The measured offset voltages were found to be about 173-365uV. Meanwhile, in ...