• Title/Summary/Keyword: Overmodulation compensation

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Static Overmodulation Strategies of Two Phase Full Bridge Inverter (2상 풀브릿지 인버터의 정적 과변조 기법)

  • Choi, Seung-Cheol;Lee, Byung-Song;Park, Chan-Bae;Mok, Hyung-Soo;Kim, Sang-Hoon;Kim, Young-Ki
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.220-226
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    • 2010
  • In this paper, the static overmodulation is proposed for the 2-phase full bridge inverter. The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation range. The linear modulation range and static overmodulation range are defined in the 2-phase full bridge inverter. The overmodulation strategies which increase a voltage utilization until the 4-step mode by linearization of the output voltage in overmodulation range are proposed. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. Simulation and experimentation results demonstrate the effectiveness of the proposed algorithms.

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Method for Improving Overmodulation Performance of an Inverter for the Enhanced Output Torque of AC Motors (교류 전동기의 출력 토크 향상을 위한 인버터의 과변조 성능 개선 방법)

  • Jeong, Hye-In;Kim, Sang-Hoon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.4
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    • pp.273-278
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    • 2019
  • This study proposes a method for improving the overmodulation performance of a three-phase inverter to obtain an enhanced output torque for the AC motors. In the inverter-fed AC motor drives, the output torque of the motor can be enhanced by utilizing the overmodulation region as well as the linear modulation regions of the inverter. The overmodulation method is used for this overmodulation operation of the inverter. However, the voltage gain, the ratio of the output voltage of the inverter to the reference voltage achieved by the conventional overmodulation methods becomes nonlinearly smaller than unity. Therefore, the effect of improving the output torque of the AC motors is insignificant even when the overmodulation region is utilized. In this study, we propose a method that improves the overmodulation performance of the inverter by compensating the limited amount of the reference voltage in the overmodulation operation to enhance the output torque of the AC motors. The effectiveness of the proposed method is verified through the simulations and experiments with an 800 W permanent magnet synchronous motor.

An Overmodulation Strategy for SVPWM Inverter (SVPWM인버터의 과변조 기법)

  • Kim, Sang-Hoon;Choi, Yun-Young
    • Journal of Industrial Technology
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    • v.20 no.B
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    • pp.147-154
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    • 2000
  • This paper proposes an overmodulation strategy for space-vector PWM(SVPWM). The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation region. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. The practical implementation is simple and it is applied to improve an output voltage of SVPWM controlled AC Motor in the steady-state. The characteristic of the proposed strategy is confirmed by simulations and experiments for a V/F control of a induction motor.

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Static Overmodulation Strategies of Two Phase Full Bridge Inverter (2상 풀브릿지 인버터의 정적 과변조 기법)

  • Choi, Seung-Cheol;Kim, Young-Ki;Kim, Sang-Hoon;Kim, Hyeong-Cheol;Mok, Hyung-Soo
    • Proceedings of the KIPE Conference
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    • 2010.07a
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    • pp.45-46
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    • 2010
  • In this paper, the static overmodulation is proposed for the 2-phase full bridge inverter. The overmodulation strategy increases a fundamental output voltage and improves a voltage utilization up to the maximum in the overmodulation range. To maintain a linearity of the relation between a reference voltage and a fundamental output voltage, this paper suggests a compensation voltage, whose magnitude or phase is modified to the proposed control scheme. Simulation and experimentation results demonstrate the effectiveness of the proposed algorithms.

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A Output Voltage Linearization in Overmodulation Region of the Space Vector PWM (공간벡터 PWM의 과변조 영역에서 출력전압 선형화)

  • Bae, Jang-Ho;Kim, Yuen-Chung;Won, Chung-Yuen;Choi, Jong-Mook;Gi, Sang-Woo;Bae, Gi-Hun
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.36S no.11
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    • pp.128-139
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    • 1999
  • This paper proposes a linearization technique for the space vector modulation method, which increases the linear control range of inverter up to the 6-step inverter. This method is based on fourier series expansion of the desired output voltage of the inverter to calculate the compensation angle in continuous switching mode and holding angle in discontinuous switching including the 6-step mode respectively. The approximation equation of these angles are used for compensation of fundamental voltage in overmodulation range. Therefore, it is possible to obtain the linear control and the maximized utilization of PWM inverter output voltage.

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Output Voltage Harmonics Analysis of NPC Type Three-level Inverter (NPC형 3레벨 인버터의 출력전압 고조파 분석)

  • Kwon, Kyoung-Min;Choi, Jae-Ho;Chung, Gyo-Bum
    • 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.

Improvement of Overmodulation Performances by Voltage Feedback Compensation (전압 피드백 보상에 의한 과변조 성능 향상)

  • Jeong, Hye-In;Kim, Sang-Hoon
    • Proceedings of the KIPE Conference
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    • 2018.11a
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    • pp.181-182
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    • 2018
  • 본 논문에서는 전압 피드백 보상에 의한 동적 과변조 기법의 성능 향상 방법을 제안한다. 전동기 구동 시스템에서 인버터는 선형 변조 영역에서 동작할 경우 단순히 전압 이득이 1인 전압 증폭기로 볼 수 있다. 그러나 과변조 영역에서는 기존의 동적 과변조 기법 적용 시 지령 전압에 대한 인버터 출력 전압의 비선형성으로 인해 전압 이득이 1보다 작아진다. 따라서 과변조 성능이 저하되는데 본 논문에서는 제한된 전압을 피드백 보상하여 과변조 성능을 향상시켰다. 이로 인해 구동 전동기의 출력 토크 성능 및 전류 제어 동특성이 향상될 수 있다. 제안된 방법을 800W PMSM(Permanent Magnet Synchronous Motor)의 약자속 제어에 적용하여 그 효용성을 확인하였다.

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Design of Low Cost Controller for 5[kVA] 3-Phase Active Power Filter (5[kVA]급 3상 능동전력필터를 위한 저가형 제어기 설계)

  • 이승요;채영민;최해룡;신우석;최규하
    • The Transactions of the Korean Institute of Power Electronics
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    • v.4 no.1
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    • pp.26-34
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    • 1999
  • According to increase of nonlinear power electronics equipment, active power filters have been researched and developed for many years to compensate harmonic disturbances and reactive power. However the commercial of active power filter is being proceeded slowly, because the cost of active power filter compared to the passive filter for harmonic and reactive power compensation is expensive. Especially, the use of DSP (Digital Signal Processing) chip, which is frequently used to control 3-phase active power filter, is a factor of increasing the cost of active power filters. On the other hand, the use of only analog controller makes the controller's circuits much more complicate and depreciates the flexibilities of controller. In this paper, a controller with low cost for 5[kVA] 3-phase active power filter system is designed. To reduce the expense of active filter system, the presented controller is composed of digital control part using Intel 80C196KC $\mu$P and analog control part using hysteresis controller for current control. Characteristic analysis of designed controller for active filter system is performed by computer simulation and compensating characteristics of the designed controller are verified by experiment.tegy can apply to the vector control, leading to better output torque capability in the ac motor drive system. This strategy is that in the overmodulation range, the d-axis output current is given a priority to regulate the flux well, instead the q-axis output curent is sacrificed. Therefore, the vector control even in the overmodulation PWM operation can be achieved well. For this purpose, the d-axis output voltage of a current controller to control the flux is conserved. the q-axis output voltage to control the torque is controlled to place the reference voltage vector on the hexagon boundary in case of the overmodulation. The validity of the proposed overall scheme is confirmed by simulation and experiments for a 22[kW] induction motor drive system.

A Hybrid CBPWM Scheme for Single-Phase Three-Level Converters

  • Wang, Shunliang;Song, Wensheng;Feng, Xiaoyun;Ding, Rongjun
    • Journal of Power Electronics
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    • v.16 no.2
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    • pp.480-489
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    • 2016
  • A novel hybrid carrier-based pulse width modulation (CBPWM) scheme that combines unipolar and dipolar modulations is proposed for single-phase three-level rectifiers, which are widely applied in railway traction drive systems. The proposed CBPWM method can satisfy the volt-second balancing principle in the complete modulation index region through overmodulation compensation. The modulation scheme features two modulation modes: unipolar and dipolar. The operation range limits of these modulation modes can be modified by changing the separation coefficient. In comparison with the traditional unipolar CBPWM, the proposed hybrid CBPWM scheme can provide advantageous features, such as lower high-order harmonic distortion of the line current and better utilization of switching frequency. The separation coefficient value is optimized to achieve the maximum utilization of these advantages. The experimental results verify the feasibility and effectiveness of the proposed hybrid CBPWM scheme.