• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.43-44
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• 2015

본 논문에서는 3-레벨 인버터의 공통 모드 전압 변동 제거의 목적으로 사용되는 MVPWM(Medium Vector PWM의 과변조 특성을 분석한다. MVPWM의 과변조 특성은 다음과 같다. 1) 과변조 상태에서도 동일한 공통모드전압을 갖는 7개의 벡터만 선택한다. 2) 진폭변조지수를 증가시킬 때 선형영역에서 비선형영역으로의 천이가 연속적이다. 본 논문에서는 시뮬레이션을 통하여 MVPWM의 위와 같은 과변조 특성을 밝힌다.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.233-240
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• 1998

This paper presents a high efficiency low switching PWM technique for the propulsion system of Electric car. In order to achieve the continuous voltage control to six-step and a low harmonics with low switching frequency under 500㎐, the synchronous technique is combined with a space vector overmodulation and implemented by using DSP. Improved performance and a validation of proposed method is shown by the experimental results using a 1.65MVA IGBT VVVF inverter and inertia load equivalent to 160 tons electric cars.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.6
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• pp.472-480
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• 2009

This paper describes the overmodulative SVPWM technique and harmonics analyses of three phase NPC type three-level inverter to the modulation index. Three phase NPC type three-level inverter adopted SVPWM to extend the linear region to 0.907, moreover, the following voltage compensation using Fourier series was adopted in the region of overmodulation to make it work to six-step level. PD type of multi carrier method is used with the double Fourier series for the analysis of output power harmonics characteristic. Simulation was performed by PSIM, and the harmonics characteristics of 3-level inverter in each region are analyzed. The side band harmonics of carrier frequency are dominant in the linear region, but these harmonic components are decreased as the inveter goes to overmodulation region, and the harmonics due to the fundamental frequency is increased gradually at the same time. The harmonic analyses are verified through the simulation and experimental results under the same condition.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2224-2226
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• 1997

공간벡터 펄스폭변조법과 관련하여 과변조시의 전류제어성능을 향상시킬 수 있는 벡터 과변조의 새로운 연산 알고리즘으로 유효전압벡터를 반지름으로 하는 원을 이용하여 수정된 기준전압벡터가 위치할 섹터를 구하고, 전압제한 6각형을 나타내는 전압벡터식을 이용하여 동일한 수식으로 벡터과변조하는 간결한 새로운 알고리즘을 제시하고, 이를 전류제어 시뮬레이션에 적용하였다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.616-618
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• 1996

This paper presents an unipolar PWM which commutated switching device only in a half period. This method reduced switching loss significantly because of decreasing switching number in n period. In high speed motor drive needed high frequency above 300 Hz fundamental frequency, this method is suited very well. This paper described the principle of unipolar PWM method, analyzed harmonic spectrum and compared with bipolar PWM, Modified PWM and Overmodulation method in switching loss.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.2
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• pp.118-124
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• 1998

This paper describes a relationship of a space vector PWM and a sinusoidal PWM and presents that the space vector PWM can produce linearly the output voltage to the unity MI(modulation index). At first, reference angles and holding angles are derived from expanding a Fourier series of the reference voltage waveform and then the angles are used for the inverter switching to linearize transfer characteristics of the inverter. In addition, the harmonic components of the output voltage are analyzed and on-line control is shown to be feasible by approximating in piecewise-linearization the reference and holding angles versus the MI. In V/f control of the induction motor, it is verified by the experiment that the motor current is changed smoothly for the variation of the inverter input voltage and the change of the reference voltage.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.19-21
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• 2006

This paper presents the control method that inverter output keeps to linear to reference voltage of Synchronous Reluctance Motor using DC Link voltage Synthesis. The Inverter output voltage cannot be displayed to linear about inverter reference voltage if Real DC Link voltage is different from DC Link voltage of PWM amplitude. Also, the overmodulation that there is linearity broken if reference voltage is out of range that inverter can output voltage. Torque ripple generates the vibration and noise of a motor. This paper proposes the control method so that torque ripple decreases and the linearity of inverter output keeps using the DC Link voltage Synthesis.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.393-404
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• 2016

In this paper, a carrier-based pulse with modulation (PWM) strategy for three-phase three-level inverter is dealt with, which can keep the common mode voltage constant with minimized switching frequency. The voltage gain and the switching frequency in overall operating ranges including overmodulation are investigated and the analytic equations are presented. Finally, the leakage current reduction effect is confirmed by carrying out simulation and experiment. It will be pointed out that the leakage current cannot be perfectly eliminated because of the dead time.

• Journal of the Korean Society for Railway
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• v.5 no.4
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• pp.267-275
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• 2002

The traction drive system for the urban transit maglev system is described in this paper. To control the magnitude and frequency of the output voltage of induction motor transiently, the vector control strategy is generally used. But in case of the traction drive system for the railway vehicle, it is difficult to use the vector control caused by the one-pulse mode in the high speed region. Therefore, this paper proposes the control strategy combined the vector control in the low speed region and the slip frequency control in the high speed region. And also, the overmodulation PWM method is discussed to make the change to the one-pulse mode softly. The performance of the proposed traction drive system is verified by the MATLAB simulation results.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.72-76
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• 1997

Interior permanent magnet synchronous motors can be applied to applications requiring wide-speed operation. The current control scheme of an interior permanent magnet synchronous (IPM) motor via feedback linearizing technique is proposed. As the available voltage controlling the armature current is small in transient operations and/or flux-weakening region, the current control performance can be deteriorated. The high performance overmodulation strategy is also proposed to improve the current responses. The control performances are confirmed by simulations.