• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1090-1100
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• 2017

This paper presents the comparison of starting current characteristics of a three-phase induction motor fed by two types of soft starters. The first soft starter under investigation is a conventional AC voltage controller on the basis of a phase-control technique. The other is the proposed asynchronous PWM AC chopper which is developed from the conventional synchronous PWM AC chopper. In this paper, the proposed asynchronous PWM AC chopper control scheme is developed by generating only two asynchronous PWM signals for a three-phase main power circuit (6 switching devices) from a single voltage control signal which is compared with a single sawtooth carrier signal. By this approach, the PWM signals are independent and easy to implement since the PWM signals do not need to be synchronized with a three-phase voltage source. Details of both soft starters are discussed. The experimental and simulation results of the starting currents are shown. It is found that the asynchronous PWM AC chopper efficiently works as a suitable soft starter for the three-phase induction motor due to that the starting currents are reduced and are sinusoidal with less harmonic contents, when being compared with the starting current waveforms using the conventional phase-control starting technique. Also the proposed soft starter offers low starting electromagnetic torque pulsation.

• Proceedings of the KIEE Conference
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• 2006.10b
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• pp.147-153
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• 2006

Voltage unbalance will be generated by the load unbalance operation such as combination operation of single & three phase load and current unbalance will be more severe by the deteriorated voltage quality. Under the these unbalance conditions, all power electronic converters used in different types of electronic systems can increase harmonic disturbances by injecting harmonic currents directly into the feeder grid of three phase 4-wire. Harmonic current may cause torque to decrease. it may also overheat or become noisy and torque oscillation in the rotor can lead to mechanical resonance and vibration. This paper presents a scheme on the characteristics of induction motor under the combination of linear & non-linear loads at the three phase 4-wire power distribution system by the unbalance and harmonic components. It was able to confirm that the number of torque pulsation decreased and torque ripple values increased by the harmonics that reduction was difficult by five harmonics filters at additional driving time of single-phase non-linear load.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.201-204
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• 2001

In this paper, a single-phase to three-phase PWM converter topology using six switches only for low cost induction motor drive is proposed. The converter topology is of lower cost than the conventional one, which gives sinusoidal input current, unity power factor, dc output voltage control and bidirectional power flow In addition, the source voltage sensor is eliminated by controlling the deviation between the model current and the system current to be zero. The performance of the proposed converter has been demonstrated through the computer simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.1 no.1
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• pp.20-26
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• 1996

The common drive method of the single phase induction motor(SPIM) is to install a start capacitor and a centrifugal switch in series with the auxiliary winding. In this paper, the phase angle voltage sequence controller is proposed to eliminate a start capacitor and a centrifugal switch of SPIM. In comparison with the capacitor start system of SPIM, the proposed control system shows that it contributes to saving the starting current about 57% and to improving of the starting efficiency of SPIM. The proposed starting characteristics of the SPIM is obtained with this strategy through simulation and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.5
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• pp.450-454
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• 2003

This paper proposes a new driving scheme for single-phase SRM. The driving scheme is very simple and inexpensive. By use of this scheme, simple power devices based on low switching losses enable to high efficiency SRM drive. Starting, One of the main problem in single-phase SRM is overcame by a new starting algorithm with one hall sensor and a parting magnet. The proposed single phase SRM has a high efficiency and robust drive characteristics compared to that of a universal motor.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.660-662
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• 2002

The single phase line start permanent magnet motor has high efficiency and power factor when it operates synchronous speed. The rotor structure is composed of permanent magnet and cage bars. The motor is accelerated by rotor bars and synchronized by magnet and rotor saliency. but starting torque is disturbed by magnet braking torque so, to obtain good starting performance and synchronizing capability. the design of proper permanent magnet is required. This paper is represented performance of start ing and synchronizing by changing permanent magnet thickness

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.198-206
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• 2017

This paper presents a novel scheme to estimate the rotor position of a single-phase hybrid switched reluctance motor (HSRM). The back-EMF generated by the permanent magnet (PM) field whose performance is motor parameter independent is adopted as an index to achieve the sensorless control. The differential value of back-EMF is calculated by hardware and processed by DSP to capture a fixed rotor position four times for every mechanical cycle. In addition, to accomplish the normal starting of HSRM, the determination method of the turn-off time position at the first electrical cycle is also proposed. In this way, a sensorless operation scheme with adjustable turn on/off angle can be achieved without substantial computation. The experimental verification using a prototype drive system is provided to demonstrate the viability of the proposed position estimation scheme.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.149-151
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• 2006

This paper shows the characteristic analysis of single-phase LSPM(Line Start Permanent Magnet) synchronous motor considering overhang structure. To obtain the dynamic and steady performance of the motor, the D-Q equivalent circuit is used and the circuit parameters are extracted by 3D FEM. The performance of the model with overhang is compared with conventional model without overhang on the condition that both models have the same volume of the permanent magnet.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.86-88
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• 2003

The efficiency of electric machine is important due to increase of interest about energy saving. Single Phase Line Start Permanent Magnet Synchronous Motor has high efficiency and power factor. LSPMSM offer a high efficiency as compared induction motor which are used in the home appliance. The analysis and design of LSPMSM is difficult because of unbalanced rotating magnetic field, nonlinear characteristics and rotor saliency. To consider these effects, F.E.M(Finite Element Methods) is coupled equivalent circuit methods. In this paper, a methods of analysis and design using F.E.M and equivalent circuit is represented.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.5
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• pp.295-304
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• 2004

This paper deals with characteristic analysis method using d-q axis equivalent circuit considering iron loss in a single-phase line-start permanent magnet synchronous motor. The iron loss resistance to account for the iron loss is included in the equivalent circuit to improve the modeling accuracy. Furthermore, for the improved calculation of the iron loss, the iron loss is calculated from the magnetic flux density by 2-dimensional finite element method. The result is represented as the iron loss resistance and connected in parallel with the total induced voltage. Therefore, the currents can be expressed as the summation the output current with the current corresponding to the iron loss. Finally, the steady state characteristic analysis results are compared with the experimental results to verify this approach.