• Journal of Power Electronics
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• v.18 no.5
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• pp.1424-1433
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• 2018

This paper presents a novel space vector pulse-width modulation (SVPWM) to synthesize an arbitrary non-sinusoidal phase voltage. The key of the proposed method is that the switching vectors used to comprise the reference vectors in the ${\alpha}_1-{\beta}_1$ frame and the ${\alpha}_3-{\beta}_3$ frame are decoupled. In the ${\alpha}_1-{\beta}_1$ frame, the reference vector is comprised by near two large vectors. The corresponding vector comprised by the two vectors in the ${\alpha}_3-{\beta}_3$ frame is considered as a disturbance, which is restrained by close-loop control. In the ${\alpha}_3-{\beta}_3$ frame, there are two methods to comprise the reference vector. Method I is a near two middle vectors method. Method II uses near four vectors (two middle and two little vectors). The proposed SVPWM using decoupled switching vectors can guarantee a maximum modulation index in the ${\alpha}_1-{\beta}_1$ frame. The effectiveness of the proposed method is verified by simulated and experimental results under various operation conditions.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.71-72
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• 2011

This paper presents a novel and direct dead time compensation method of the 3 phase inverter using space vector pulse width modulation(SVPWM) topology. In the turn on time calculation of the effective voltage, the dead time effect is directly compensated according to the current direction of the midium voltage reference. Since the turn on time of the effective voltage vector is affected by the dead time, the loss time is compensated to turn on time of the effective voltage vector. And the dead time is added to the calculated voltage vector switching times according to the current direction. For the more effective compensation, the direction of the midium phase current is considered by the practical direction and voltage drops in the power devices. The proposed method can compensate the dead time which is considered feedback error or direction of middle phase current without coordinate transform in added controller. The proposed dead time compensation scheme is verified by the computer simulation and experiments of 3 phase R L load.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.3
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• pp.61-68
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• 2015

When medium and large induction motors are driven by 2-level inverters with low switching frequency, induction motors provoke deteriorated performances resulted from large torque ripples, flux ripples, and large current distortion. Model predictive torque control(MPTC) for a fast torque control of induction motors is also suffered from large torque ripples when the induction motors are fed by 2-level inverters that are based on 6 active voltage vectors with low switching frequency restricted. To solve this problem, this paper proposes a new MPTC method based on both a 12 active voltage vector and an optimized duty ratio calculation. The proposed control strategy illustrates its effectiveness under the various operating conditions through simulation works.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2299-2304
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• 2010

A sensorless vector control of an induction motor provides a good performance in the middle and high speed region. However, in the low speed region, it is very difficult to implement the sensorless vector controller because the feeding voltage measured by the motor is very low. In this paper, we designed the sensorless vector controller of an induction motor using the estimate of the slip frequency. To verify the performance of the proposed controller, an experiment has been performed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2474-2479
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• 2012

A sensorless vector control of an induction motor provides a good performance in the middle and high speed region. However, in the low speed region, it is very difficult to implement the sensorless vector controller because the feeding voltage measured by the motor is very low. In this paper, to improve the performance of a sensorless vector control of an induction motor in the low speed region under 3Hz, we proposed the fuzzy logic controller using the zooming algorithm. To verify the performance of the proposed controller, an experiment has been performed.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.308-312
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• 2003

The objective of this paper is to investigate the power spectrum of a three-phase and a two-phase RCD (Random Pulse Centered Displacement) PWM scheme. The two-phase or three-phase pulses of RCD-PWM scheme are mutually center-aligned as in SVM(Space Vector Modulation), but the common pulse center is displaced randomly from the middle of the period. To verify the validity of the proposed two-phase RCD-PWM scheme, the power spectra of the output voltage, the d.c link current in the inverter drives and the radiated acoustic noise are experimentally investigated. And, the performance of the proposed two-phase RCD-PWM scheme was compared and discussed with the conventional three-phase RCD-PWM scheme.

• Journal of Power Electronics
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• v.15 no.1
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• pp.246-255
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• 2015

This paper presents experimental results and its assessment of a variable-speed wind power generation system (VSWPGS) using permanent magnet synchronous generator (PMSG) and boost chopper circuit (BCC). Experimental results are obtained by a test bench with a wind turbine emulator (WTE). WTE reproduces the behaviors of a windmill by using servo motor drives. The mechanical torque references to drive the servo motor are calculated from the windmill wing profile, wind velocity, and windmill rotational speed. VSWPGS using PMSG and BCC has three speed control modes for the level of wind velocity to control the rotational speed of the wind turbine. The control mode for low wind velocity regulates an armature current of generator with BCC. The control mode for middle wind velocity regulates a DC link voltage with a vector-controlled inverter. The control mode for high wind velocity regulates a pitch angle of the wind turbine with a pitch angle control system. The hybrid of three control modes extends the variable-speed range. BCC simplifies the maintenance of VSWPGS while improving reliability. In addition, VSWPGS using PMSG and BCC saves cost compared with VSWPGS using a PWM converter.