• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.126-133
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• 2004

In this paper, a new current control algorithm is proposed for four-switch three-phase brushless DC(BLDC) motor drives, which are suitable for low cost applications. A current reference generation scheme is developed and implemented to obtain high performance characteristics in the four-switch system, such as small torque ripple and fast dynamic speed/torque response. Especially, the proposed scheme can successfully reduce the torque ripple during commutations, so that it can be expected that the four-switch system can be much more practically applied for the industrial application areas.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1026-1029
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• 1993

Inherent speed-torque performance of Switched Reluctance Motor is similar to that of series wound DC motor. Thus, the speed of the motor is extremely regulated according to load torque. For the purpose of controlling the speed and torque of SRM it is necessary to change the applied DC link voltage or the switch-ON and switch-OFF angles which control the phase current of the motor. This paper describes speed-torque characteristics of an integral horse power Switched Reluctance Motor by adjusting the switch-ON and switch-OFF angles. Speed at rated load torque can be regulated by adjusting the switching angles and the control scheme is applied to 2kW, 3 phase, 6/4 SRM.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.6
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• pp.396-401
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• 2004

Single phase induction motor(SPIM) is one of the most widely used type of low power AC motors in the world, especially for domestic or commercial applications where a three phase power supply is not available. Single phase induction motors have no starting torque their own. So there are several ways of starting single phase induction motors. The most common type is the starting capacitor installed in series with the auxiliary winding to increase the starting torque. In the conventional systems, this function is conducted by a centrifugal switch. But the mechanical centrifugal switch has many problems such as switch malfunction. This paper presents the auxiliary winding control using digital universal starting switch to overcome these shortcomings of centrifugal switch.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.506-513
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• 2001

The torque of an SRM depends on the phase current and derivative of inductance. But an SRM is difficult to control the desired torques because of saturation in magnetic circuit An SRM is controlled by parameters of input voltage, and switch on , off angle The switch on off angles of an SRM regulate the magnitude and shape of current waveform and decide the magnitude and shape of torque This paper proposes an the optimization control scheme by adjusting both the switch on an switch off angle . The switch off angles are decided by reference of efficiency using simulation and experiments. The switch on angles are decided by load torque , And the dwell angles are controlled for torque control and speed control using GA-neural network which is used to simulated the reasonable switching angle.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.472-476
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• 2003

In this paper, a new current control algorithm is proposed for four-switch three-phase brushless DC(BLU) motor drives, which are suitable for low cost applications. A current reference generation scheme is developed and Implemented to obtain high performance characteristics in the four-switch system, such as small torque ripple and fast dynamic speed/torque response. Moreover, the proposed scheme can successful1y eliminate the torque ripple during commutations, so that it can be expected that the four-switch system can be much more practically applied for the industrial application areas.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1356-1361
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• 2008

A switched reluctance generator(SRG) has simple magnetic structure, and needs simple power electronic driving circuit. But, a SRG are no windings or permanent magnets on the rotor, and there are concentrated windings placed around each salient pole on the stator. Because of the characteristics of time-sharing excitation, the control of SRG is very flexible. And there are several parameters for controlling SRG, such as switch turn-on angle, switch turn-off angle, and exciting voltage and controlling mode, all these will affect the generation greatly. A SRG has positive torque at increasing inductance region and negative torque at decreasing inductance region. In this paper, we studied characteristics about the switch turn-on and off angles according to switch method for constant output voltage of the fixed speed SRG. It is the acoustic noise and torque ripple characteristics. Characteristics for a switch angle and method are presented by experiment using a 50W SRG with 12/8 poles.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.722-732
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• 2018

Dual type Independent multi-phase BLDC Motor (DI-BLDCM) is designed to be robust to faulty conditions of motor and drive system. Despite the efforts of the motor design, open-switch faults of DI-BLDCM drive system cause the torque ripple of the motor. This torque ripple makes unwanted sound noise and mechanical vibration of associated systems. This paper proposes four methods for compensating the torque ripple and compares the characteristics of each proposed method. All proposed methods are able to reduce the torque ripple to similar level of the healthy condition, although the motor operates in open-switch fault conditions. However, these methods have different characteristics in various fault conditions. Therefore, from the results of the comparison, the suitable method is selected for the various fault conditions. The feasibility of the proposed methods is proved by the several experimental results.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1147-1149
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• 2005

Time switch is widely used to reduce the energy loss by selecting the duration of daily-based operating pattern for the electrical apparatus. Driving force of the time switch is the single-phase step motor which has the starting torque due to the asymmetrical airgap. Cogging and total torque of the tapered-airgap motor is analyzed by finite element method.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.267-270
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• 2002

Fractional horse power single phase induction motors have no starting torque their own. So there are several ways of starting single phase induction motors. The most common type is the starting capacitor installed in series with the auxiliary winding to increase the starting torque. Also, the auxiliary winding is disconnected once the speed of the motor reaches 70 to 80 [%] of the rated speed. In the conventional systems, this function is conducted by a centrifugal switch. But the mechanical centrifugal switch has many problems such as switch malfunction. This paper presents the new methods of electronic starting switch by inductor to overcome these shortcomings of centrifugal switch.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.251-260
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• 2015

The main purpose of this paper is to describe a DTC (direct torque control) method for four-switch brushless dc motor (BLDCM) drive. In the method, a novel voltage space vector modulation scheme, an optimal switching table, and a flux observation method are proposed. Eight voltage vectors are summarized, which are selected to control BLDCM in SVPWM pattern, and an optimal switching table is proposed to improve the torque distortion caused by midpoint current of the split capacitors. Unlike conventional flux observers, this observer does not require speed adaptation and is not susceptible to speed estimation errors, especially, at low speed. Global asymptotic stability of the flux observer is guaranteed by the Lyapunov stability analysis. DC-offset effects are mitigated by introducing a PI component in the observer gains. This method alleviates the undesired current and torque distortion which is caused by uncontrollable phase. The correctness and feasibility of the method are proved by simulation and experimental results.