• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2604-2606
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• 1999

The dead time deteriorates the output performance of the PWM inverter so that various compensation schemes have been proposed. If the modulation index is rendered with the low output frequencies, those schemes do not work well because of the zero clamping phenomena. In this paper, we investigate the influence of the dead time minimization algorithm on the low output voltage reference. The validity of the algorithm is examined by comparing the simulation results with those of conventional methods.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.830-835
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• 1998

This paper describes a new digital control method of 3-phase PWM inverter with LC filter for uninterruptible power supply(UPS). The overall control system is based on the dead beat control, which has the minor loop of current control within the voltage control major loop. In this paper, the full-order disturbance observer is proposed to compensate the disturbances generated due to a sudden change of load currents. The proposed disturbance observer is composed of dead beat observer which estimates state values within a finite time, and cancels the disturbances by adding feedforward compensation loop in the control system. In addition, on order to remove a defect of oscillation generated in output of conventional dead beat controller, a modified dead beat algorithm is proposed in this paper.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.2
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• pp.162-168
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• 1997

Digital variable structure controller(DVSC) is implemented to control the temperature for the hot water heating circulating pump control system. For the DVSC, a control algorithm is suggested, which using a nonlinear sliding surface and a PID sliding surface outside and inside of steady state error boundary layer, respectively. Smith predictor algorithm is used for the compensation of long dead time. The DVSC of the suggested algorithm yields improved control performance compared with the one of existing algorithm. The system responses with the suggested DVSC shows good responses without overshoot and steady state error inspite of heating load change. By decreasing sampling time, dead time and rise time are increasing, and system output noise by flow dynamics is amplified.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.455-460
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• 2003

The a PWM VSI, the voltage distortion exists between the reference and output voltage. This distortion is caused by the intended blanking time and the inherent characteristics of the switching devices which are function of the operating condition. In this paper, the dead-time effects are analysed and a new on-line estimation method for a PMSM is proposed to compensate time varying dead-time effects

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.296-300
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• 1989

The paper proposes a method to eliminate harmonics of PWM inverter fed induction motor system using Walsh series. In other words, this paper presents technique of the selective harmonics elimination(SHE) by W-FT series in three phase PWM inverter output waveform. A microprocessor(8086 CPU) - controlled three phase induction motor system in order to verify this algorithm is present. It is designed for a three output voltage in the 1$\sim$60 Hz inverter with the 5th and 7th harmonics, 5th, 7th, 11th, and 13th, harmonics eliminated, and with the fundamental wave amplitude proportional to the output frequency. In the PWM inverter, dead time circuit is inserted in the switching si gnats to prevent the de link shortage. This paper is deals with quantative prediction of dead-time effect and its compensation in PWM inverters. The performance of the compensation circuits is confirmed by the experiment.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.1
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• pp.34-40
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• 1994

The design and implementation of a fuzzy self-organizing controller for an environmental temperature chamber is discussed. The chamber is a non-linear, time-variant system with delay-time and dead-time. And the parameter tuning is required in PI control when the performance degraded. However the proposed fuzzy-SOC monitors the performance of the process. modifies the data base, and performs the delay-time compensation based on the idealized process model. A series of experiments was performed for the conventional PI and the fuzzy-SOC. These experimental results show the usefulness of the fuzzy-SOC.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.407-411
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• 1998

Traditional carrier-based PWM method cannot produce maximum output voltage due to dead-time compensation, w which results in degradation of voltage utilization factor compared with ideal PWM inverters, Dual-carrier PWM has b been proposed as an alternative method to solve this problem. But this method requires paying attentition to changing r reference voltage in the vicinity of maximum voltage to ensure enough dead-time. Novel dual-carrier PWM method and i it's practical implementation is proposed in this paper. The reference voltage can be changed without any restriction in t this method.

• Journal of Power Electronics
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• v.16 no.3
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• pp.960-969
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• 2016

High-power three-level voltage-source converters are widely utilized in high-performance AC drive systems. In several ultra-power instances, the harmonics on the grid side should be reduced through multiple rectifications. A combined harmonic elimination method that includes a dual primary-side series-connected winding transformer and selective harmonic elimination pulse-width modulation is proposed to eliminate low-order current harmonics on the primary and secondary sides of transformers. Through an analysis of the harmonic influence caused by dead time and DC magnetic bias, a synthetic compensation control strategy is presented to minimize the grid-side harmonics in the dual primary side series-connected winding transformer application. Both simulation and experimental results demonstrate that the proposed control strategy can significantly reduce the converter input current harmonics and eliminates the DC magnetic bias in the transformer.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.2
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• pp.97-103
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• 2005

Most car navigation systems(CNS) estimate the vehicle's location using global positioning system(GPS) or dead reckoning(DR) system. However, the estimated location has undesirable errors because of various noise sources such as unpredictable GPS noises. As a result, the measured position is not lying on the road, although the vehicle is known to be restricted on the road network. The purpose of map matching is to locate the vehicle's position on the road network where the vehicle is most likely to be positioned. In this paper, we analyze some general map matching algorithms first. Then, we propose a map matching method using compensation vectors to improve the performance of map matching. The proposed method calculates a compensation vector from the discrepancy between a measured position and an estimated position. The compensation vector and a newly measured position are to be used to determine the next estimation. To show the performance improvement of the map matching using compensation vectors, the real time map matching experiments are performed. The real road experiments demonstrate the effectiveness and applicability of the proposed map matching.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.443-447
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• 1999

The AC drive systems of a voltage source inverter and an induction motor. The inverter non linearity caused by the turn on/off time dependency of the current level in the switching IGBT is described in the first part of this paper. To improve the low-speed drive characteristics, accurate applied voltage calculation is proposed under considerations of the compensations for the quantization error in the digital controller, the forward voltage drop of switching drives and the dead time of the inverter. The experimental studies show the improved drive characteristics.