• Title, Summary, Keyword: Medium Voltage Motor

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The Evaluation of Medium Voltage Motor's Current and Voltage Harmonics during Loading

  • Alboyaci, Bora;Yorukeren, Nuran
    • Journal of Electrical Engineering and Technology
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    • v.2 no.1
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    • pp.35-41
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    • 2007
  • This paper presents the results of investigating harmonic levels on medium voltage motors at loading conditions in air separation plant. The essential results of the measurements of the medium voltage motor harmonics are summarized in the values for the total harmonic distortion (THD). Motors loading case is used to assess the current and voltage harmonic distortions. Proper system analysis is important when adding a new motor starting and controlling the equipment. With the result of the paper it is possible to suggest the most appropriate starting and control method. Two medium voltage motors of air separation unit measurement results and simulations are summarized. Both current and voltage harmonic distortions are fitted by using a linear and exponential regression model. The prediction of THD values can be used for this kind of process for future planning by utilities.

Hybrid-Boost Modular Multilevel Converter-Based Medium-Voltage Multiphase Induction Motor Drive for Subsea Applications

  • Daoud, Mohamed;Elserougi, Ahmed;Massoud, Ahmed;Bojoi, Radu;Abdel-Khalik, Ayman;Ahmed, Shehab
    • Journal of Power Electronics
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    • v.19 no.3
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    • pp.714-726
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    • 2019
  • This paper proposes a hybrid-boost Modular Multilevel Converter (MMC) for the Medium-Voltage (MV) Variable Speed Drives (VSDs) employed in subsea applications, such as oil and gas recovery. In the presented architecture, a hybrid-boost MMC with a reduced number of semiconductor devices driving a multiphase Induction Machine (IM) is investigated. The stepped output voltage generated by the MMC reduces or eliminates the filtering requirements. Moreover, the boosting capability of the proposed architecture eliminates the need for bulky low-frequency transformers at the converter output terminals. A detailed illustration of the hybrid-boost MMC operation, the expected limitations/constraints, and the voltage balancing technique are presented. A simulation model of the proposed MV hybrid-boost MMC-based five-phase IM drive has been built to investigate the system performance. Finally, a downscaled prototype has been constructed for experimental verification.

Starting Method of BLDC Motor from Standstill to Medium Speed Without any Position Sensor (위치센서없는 영구자석 매입형 전동기의 기동 방식)

  • LEE Joon-Hwan;KIM Tae-Duk
    • Proceedings of the KIPE Conference
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    • pp.1-4
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    • 2004
  • From standstill to medium speed which enough to sensing back EMF, it is not easy to drive without additional equipments due to directly proportional to flux. Conventional method to drive is 'align and go' method, so called v/f control that is increased voltage duty in proportion to the increase of frequency. Because it isn't consider load of motor and doesn't know rotor position exactly, current is supplied too much current or not enough to rotate motor. This paper is proposed starting method without any poison sensor and can drive a BLDC motor from standstill to the medium speed smoothly without any rattling and time delay compared with the conventional starting algorithm. To verify algorithm of this paper, experimental results are presented.

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Optimal Voltage Vector Selection Method for Torque Ripple Reduction in the Direct Torque Control of Five-phase Induction Motors

  • Kang, Seong-Yun;Shin, Hye Ung;Park, Sung-Min;Lee, Kyo-Beum
    • Journal of Power Electronics
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    • v.17 no.5
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    • pp.1203-1210
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    • 2017
  • This paper presents an improved switching selection method for the direct torque control (DTC) of five-phase induction motors (IMs). The proposed method is conducted using optimal switching selection. A five-phase inverter has 32 voltage vectors which are divided into 30 nonzero voltage vectors and two zero voltage vectors. The magnitudes of the voltage vectors consist of large, medium, and small voltage vectors. In addition, these vectors are related to the torque response and torque ripple. When a large voltage vector is selected in a drive system, the torque response time decreases with an increased torque ripple. On the other hand, when a small voltage vector is selected, the torque response time and torque ripple increase. As a result, this paper proposes an optimal voltage vector selection method for improved DTC of a five-phase induction machine depending on the situation. Simulation and experimental results verify the effectiveness of the proposed control algorithm.

Selection of Voltage Vectors in Three-Level Five-Phase Direct Torque Control for Performance Improvement

  • Tatte, Yogesh N.;Aware, Mohan V.
    • Journal of Power Electronics
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    • v.16 no.6
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    • pp.2162-2172
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    • 2016
  • This paper presents a Direct Torque Control (DTC) strategy for the five-phase induction motor driven by a three-level five-phase inverter in order to improve the performance of the five-phase induction motor. In the proposed DTC technique, only 22 voltage vectors out of 243 available voltage vectors in a three-level five-phase inverter are selected and are divided in 10 sectors each with a width of $36^{\circ}$. The four different DTC combinations (DTC-I, II, III and IV) for a three-level five-phase induction motor drive are investigated for improving the performance of five-phase induction motor. All four of the DTC strategies utilize a combination of the same large and zero voltage vectors, but with different medium voltage vectors. Out of these four techniques, DTC-II gives the best performance when compared to the others. This DTC-II technique is analyzed in detail for improvements in the performance of five-phase induction motor in terms of torque ripple, x-y stator flux and Total Harmonics Distortion (THD) of the stator phase current when compared to its two-level counterparts. To verify the effectiveness of the proposed three-level five-phase DTC control strategy, a DSP based experimental system is build. Simulation and experimental results are provided in order to validate the proposed DTC technique.

THERMAL-FLUID ANALYSIS FOR COOLING PERFORMANCE IMPROVEMENT OF 3.3KV(105A) COMPACT RACK TYPE MEDIUM VOLTAGE INVERTER SYSTEM (3.3kV(105A) COMPACT RACK TYPE 고압 인버터 시스템의 방열 성능 향상을 위한 열유동 해석)

  • Kim, S.Y.;Kim, S.D.;Ryoo, S.R.;You, N.K.;Kim, T.B.;Hong, C.O.;Ko, H.S.
    • Journal of computational fluids engineering
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    • v.19 no.3
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    • pp.24-28
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    • 2014
  • With ever rising concerns about saving of fossil fuel resource, there have been an increasing demand for use of energy more efficiently. The electric motor driven inverters can be a great help to improve energy efficiency. They are also used to control the motor speed to the actual need. Therefore the use of them can lead to reduce energy consumption. In particular, the medium voltage(MV) drive systems used for pumps, fans, steel rolling mills and tractions have widespread applications in the industry. They cover power ratings from 0.4MW to 40MW at the MV level of 2.3kV to 13.8kV. The majority of the installed MV drive systems however, are in the 1MW to 4MW range with voltage rating from 3.3kV to 6.6kV. But they are required to reduce size and weight like other power electronic equipments. In this paper, we studied on the 3.3kV(105A) compact rack type inverter system for improving the cooling efficiency. At first, we confirmed the tendency of temperature with computational simulation using ANSYS ICEPAK and actual experimental tests. And then we researched thermal performance improvement designs in order to reduce temperature of the transformer for the safe operation. It can reduce temperature of transformer that using pipe type flow guide in the system. As a result, we found out more efficient solution by thermal-fluid analysis.

The Electro-Mechanical Properties of Disk-Type Stator for Ultrasonic Motor (초음파 모터용 디스크형 고정자의 전기기계적 특성)

  • Lee, J.S.;Kim, B.W.;Lee, S.H.;Shin, S.I.;Nam, K.D.;Oh, H.K.;Jang, Y.J.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.339-340
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    • 2006
  • In this paper, disk-type ultrasonic motor using radial and bending vibration modes is newly designed and fabricated to measure its characteristics. As the diameter of elastic body increases, the resonant frequency decreases and its resonant frequency is about 92kHz when the physical dimensions of piezoelectric ceramic and elastic body are 28mm of diameter and 2mm of thickness, and 32mm of diameter and 2mm of thickness, respectively. When the applied voltage is 20Vpp. its speed and torque are 200rpm and 1N, respectively.

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Analysis of Cascaded H-Bridge Multilevel Inverter in DTC-SVM Induction Motor Drive for FCEV

  • Gholinezhad, Javad;Noroozian, Reza
    • Journal of Electrical Engineering and Technology
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    • v.8 no.2
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    • pp.304-315
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    • 2013
  • In this paper, analysis of cascaded H-bridge multilevel inverter in DTC-SVM (Direct Torque Control-Space Vector Modulation) based induction motor drive for FCEV (Fuel Cell Electric Vehicle) is presented. Cascaded H-bridge multilevel inverter uses multiple series units of H-bridge power cells to achieve medium-voltage operation and low harmonic distortion. In FCEV, a fuel cell stack is used as the major source of electric power moreover the battery and/or ultra-capacitor is used to assist the fuel cell. These sources are suitable for utilizing in cascaded H-bridge multilevel inverter. The drive control strategy is based on DTC-SVM technique. In this scheme, first, stator voltage vector is calculated and then realized by SVM method. Contribution of multilevel inverter to the DTC-SVM scheme is led to achieve high performance motor drive. Simulations are carried out in Matlab-Simulink. Five-level and nine-level inverters are applied in 3hp FCEV induction motor drive for analysis the multilevel inverter. Each H-bridge is implemented using one fuel cell and battery. Good dynamic control and low ripple in the torque and the flux as well as distortion decrease in voltage and current profiles, demonstrate the great performance of multilevel inverter in DTC-SVM induction motor drive for vehicle application.

Reliability Improvement of H-Bridge Multi-level Inverter for Medium-Voltage & High-Power Induction Motor Drives (고전압 대용량 유도전동기 구동용 H-브릿지 멀티레벨 인버터의 신뢰성 향상)

  • Park, Young-Min;Lee, Kwang-Hwan;Lee, Se-Hyun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.2
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    • pp.99-105
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    • 2014
  • This paper proposes the reliability improvement of H-Bridge Multi-level (HBM) inverter. This reliability can be implemented through modularization of power circuit, distribution of controller, duplication of controller and communication, and continuous operation method in case of power cell failure for driving medium-voltage & high-power induction motor. It is shown that the modularization and expansion characteristics of the HBM inverter are improved since the individual inverter modules operate more independently when using the proposed concept. Also the fault tolerance is increased by using power cell bypass. The proposed design and control methods are described in detail and the validity of the proposed system is verified experimentally in various industrial fields.

Optimized PWM Switching Strategy for an Induction Motor Voltage Control

  • Lee, Hae-Hyung;Hwang, Seuk-Yung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.527-533
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    • 1998
  • An optimized PWM switching strategy for an induction motor voltage control is developed and demonstrated. Space vector modulation in voltage source inverter offers improved DC-bus utilization and reduced commutation losses, and has been therefor recognizedas the perfered PWM method, especially in the case of digital implementation. Three-phase invertor voltage control by space vector modulation consists of switching between the two active and one zero voltage vector by using the proposed optimal PWM algorithm. The prefered switching sequence is defined as a function of the modulation index and period of a carrier wave. The sequence is selected by suing the inverter switching losses and the current ripple as the criteria. For low and medium power application, the experimental results indicate that good dynamic response and reduced harmonic distortion can be achieved by increasing switching frequency.

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