• Journal of Power Electronics
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• 제11권3호
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• pp.294-303
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• 2011

In this paper an effective five-phase induction motor (IM) and its drive methods are proposed. Due to the additional degrees of freedom, the five-phase IM drive presents unique characteristics for enhancing the torque producing capability of the motor. Also the five-phase motor drives possess many other advantages when compared to traditional three-phase motor drives. Some of these advantages include, reducing the amplitude and increasing the frequency of the torque pulsation, reducing the amplitude of the current without increasing the voltage per phase and increasing the reliability. In order to maximize the torque per ampere, the proposed motor has concentrated winding, the produced back electromotive force (EMF) is almost trapezoidal, and the motor is supplied with the combined sinusoidal plus the third harmonic of the currents. For demonstrating the superior performance of the proposed five-phase IM, the motors are also analyzed on the synchronously rotating reference frame. To supply trapezoidal current waveform and to exclude the effect of the $3^{rd}$ harmonic current, a new control stratagem is proposed. The proposed control method is based on direct torque control (DTC) and rotor flux oriented control (RFOC) of the five-phase IM drives. It is able to reduce the acoustical noise, the torque, the flux, the current, and the speed pulsations during the steady state. The DTC transient merits are preserved, while a better quality steady-state performance is produced in the five phase motor drive for a wide speed range. Experimental results clearly demonstrated a more dynamic steady state performance with the proposed control system.

• 전기학회논문지P
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• 제61권4호
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• pp.199-205
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• 2012

This paper propose a improved parameter estimations of five-phase squirrel-cage induction motor(IM) for speed control system on field oriented control(FOC). In order to high performance control of ac the motors using a FOC and DTC(direct torque control) algorithm, there are required precise motor parameters for slip calculation, flux observer, controller gain, rotor position and speed estimation, and so on. We are suggest a estimation method of the motor parameters that developing five-phase squirrel-cage IM have a stator of concentrated winding for experimental. There are results of stator winding test, no-load test, locked rotor test, and obtained equivalent circuits using manufactured experimental apparatus. For presenting the superior performance of the speed control system in adapted the parameters, experimental results are presented using a 32-bit fixed point TMS320F2812 DSP with 1.5[KW] IM.

• Journal of Power Electronics
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• 제17권5호
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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.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1177-1186
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• 2017

This paper presents a torque ripple reduction method of direct torque control (DTC) using fuzzy controller with optimal selection strategy of voltage vectors in a five-phase induction motor. The conventional DTC method has some drawbacks. First, switching frequency changes according to the hysteresis bands and motor's speed. Second, the torque ripple is rapidly increased in long control period. In order to solve these problems, some/most papers have proposed torque ripple reduction methods by using the optimal duty ratio of the non-zero voltage vector. However, these methods are complicated in accordance with the parameter. If this drawback is eliminated, the torque ripple can be reduced compared with conventional method. In addition, the DTC can be simply controlled without the use of the parameter. Therefore, the proposed algorithm is changing the voltage vector insertion time by using the designed fuzzy controller. Also, the optimized voltage vector selection method is used in accordance with the torque error. Simulation and experimental results show effectiveness of the proposed control algorithm.

• Journal of Electrical Engineering and Technology
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• 제3권2호
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• pp.224-234
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• 2008

Multi-phase machines can be used in variable speed drives. Their applications include electric ship propulsion, 'more-electric aircraft' and traction applications, electric vehicles, and hybrid electric vehicles. Multi-phase machines enable independent control of a few numbers of machines that are connected in series in a particular manner with their supply being fed from a single voltage source inverter(VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases more than or equal to five-phase. The number of series-connected machines is a function of the phase number of VSI. Theoretical and simulation studies have already been reported for number of multi-phase multi-motor drive configurations of series-connection type. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information concerning the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an MRAS estimator based sensorless control of a vector controlled series-connected two-motor five-phase drive system with current control in the stationary reference frame. Results, obtained with fixed-voltage, fixed-frequency supply, and hysteresis current control are presented for various operating conditions on the basis of simulation results. The purpose of this paper is to report the first ever simulation results on a sensorless control of a five-phase two-motor series-connected drive system. The operating principle is given followed by a description of the sensorless technique.

• Journal of Power Electronics
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• 제14권1호
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• pp.115-124
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• 2014

This paper presents the implementation of two-arm modulation (TAM) technique for the independent control of a two-induction motor drive fed by a five-leg inverter (FLI). A carrier-based space vector pulse width modulation technique for TAM is proposed to generate switching signals for FLI. Two independent three-phase space vector modulators are utilized to control two motors. The motor drive system applies two separate indirect field-oriented control methods. The stationary voltage outputs from the vector control are synthesized in the three-phase space vector modulator to generate switching signals for FLI. The performance of the independent control of the motors and the voltage utilization factor are likewise analyzed. Simulation and experimental results verify the effectiveness of the proposed method for the independent control of the two-motor drive system. The proposed technique is successfully validated by dSPACE DS1103 experimental work.

• Journal of Power Electronics
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• 제13권5호
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• pp.806-813
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• 2013

This paper aims to compare the performance of three phase induction motor drives using Five Leg Inverter (FLI) and Three Leg Inverter (TLI) configurations. An Indirect Field Oriented Control (IFOC) method using a TLI is well established and incorporated for high performance speed drives in various industries. The FLI dual motor drive system on the other hand shows good workability in the independent control of two induction motor drives simultaneously. In this experiment, the IFOC method is utilized for both drive systems, and Space Vector Pulse Width Modulation (SVPWM) is used to generate pulses for both inverters. For the FLI, the Double Zero Sequence (DZS) Injection technique is used to generate the modulation signal. The complete experiment setup is done by using a DSpace 1103 controller board. The individual motor performances are analyzed using similar schemes, equipment setups and controller parameter values. The results show similar speed performance response capability between the single motor operation using a TLI system and the two motor operation using a FLI system based on the variable speed range either in forward or reverse operation. They also show similar load rejection abilities. However, the single motor with a TLI has a better power quality aspect such as ripple current and total harmonics distortion (THD).

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.55-56
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• 2010

다상 유도 전동기(Multi phase induction motor)의 고성능 제어를 수행하기 위해서는 정확한 파라미터 계산이 필수적이다. 특히 전동기의 벡터제어(FOC, Field oriented control)나 직접토크제어(DTC, Direct torque control)와 같은 고성능 제어 시스템의 경우, 슬립 계산이나 자속관측기 그리고 PI 제어기 게인 추정에서 전동기 상수들이 필수적으로 사용된다. 본 논문에서는 실험용으로 집중권(Concentrated winding) 구조를 가지는 2kW, 5상 유도전동기를 제작하였으며, 5상 유도전동기 파라미터 추정에 대한 방법을 제시하였다. 일반적으로 다상 유도전동기의 경우 1차 공간 고조파(1st space harmonic) 성분에 대한 파라미터만을 추정하여 제어에 사용하지만, 본 논문에서는 1차 공간 고조파 성분과 3차 공간 고조파(3rd space harmonic) 성분에 대한 파라미터 추정 방법을 제시한다. 결과적으로 제안된 파라미터 추정 방법의 타당성을 확인하기 위해서 설계값과 실험값을 비교하였다.

• 한국철도학회논문집
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• 제20권1호
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• pp.43-54
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• 2017

본 논문에서는 철도차량 추진시스템을 위한 3-레그 인버터와 5-레그 인버터의 성능을 비교/분석하고 철도차량에 5-레그 인버터를 적용함에 있어 최적의 동작 조건을 제시한다. 5-레그 인버터는 두 대의 3-레그 인버터에 비해 2개의 스위치가 감소되며, 하나의 제어보드로 두 대의 3상 전동기를 독립적으로 제어할 수 있다. 이로 인해 두 대의 3-레그 인버터를 이용할 경우보다 시스템의 비용 감소와 소형화가 가능하다. 본 논문에서는 먼저 도시철도 차량에서 사용중인 유도전동기 제어 기법과 PWM 방법을 분석한다. 다음으로 5-레그 인버터의 기본 동작과 특징을 분석한다. 이러한 분석을 바탕으로 동일한 유도전동기 제어 기법과 PWM 방법을 3-레그 인버터와 5-레그 인버터에 적용했을 때 유도전동기의 속도와 토크 특성을 비교하고 분석한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.343-344
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• 2015

본 논문은 고속영역에서 3차 고조파의 영향을 고려한 5상 유도전동기의 약계자 운전을 제안한다. 5상 유도전동기는 집중권의 형태로 되어있어 공극 자속이 제 3차 공간 고조파 성분을 포함한다. 따라서 5상 유도전동기의 역기전력은 3차 고조파가 포함된 형태이므로, 5상 유도전동기의 약계자 운전은 3차 고조파 성분을 고려하여 수행해야 한다. 약계자 운전에 앞서 정격 이하의 속도에서는 간접벡터제어를 사용하고, 정격이상의 고속 영역에서는 최대 토크 발생과 전압 및 전류 제한 영역을 고려한 약계자 운전을 수행한다. 본 논문에서는 3차 고조파를 고려한 5상 유도전동기의 약계자 운전을 시뮬레이션으로 검증한다.