• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.461-462
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• 2010

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.171-178
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• 1998

This paper proposes a new overmodulation strategy to give a better voltage utilization by tracking voltage vector along hexagon sides. This strategy enables the inverter to control both magnitude and angle of current. Therefore, the vector control using this strategy can lead to better output torque dynamics compared to the conventional slip frequency control with six-step voltage, which is widely used in the traction drive. In this strategy, the d-axis output voltage of a current controller to control the flux is conserved and the q-axis output voltage to control the torque is controlled to place the voltage vector on the hexagon boundary In case of overmodulation. The limited q-axis voltage is used for anti-windup of q-axis current controller. This paper also presents a new field weakening scheme which incorporate the proposed overmodulation strategy. In this scheme, the flux level is selected by both required current limit and the available maximum voltage along hexagon sides. The validity of the proposed overall scheme is confirmed by the computer simulations for a typical traction drive with a 210[㎾] induction motor.

• Journal of Power Electronics
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• v.8 no.4
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• pp.345-353
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• 2008

In this paper, a novel loss minimization of an induction generator in wind energy generation systems is presented. The proposed algorithm is based on the flux level reduction, for which the generator d-axis current reference is estimated using support vector regression (SVR). Wind speed is employed as an input of the SVR and the samples of the generator d-axis current reference are used as output to train the SVR algorithm off-line. Data samples for wind speed and d-axis current are collected for the training process, which plots a relation of input and output. The predicted off-line function and the instantaneous wind speed are then used to determine the d-axis current reference. It is shown that the effect of loss minimization is more significant at low wind speed and the loss reduction is about to 40% at 4[m/s] wind speed. The validity of the proposed scheme has been verified by experimental results.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.29-33
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• 1998

In this paper, a new dynamic overmodulation strategy is proposed for vector-controlled induction motor drive, and a comparison experiment with conventional schemes are also performed. In overmodulation region, the proposed overmodulation scheme allocates the output voltage of inverter so that synchronous d-axis voltage is diminished in proposed overmodulation scheme allocates the output voltage of inverter so that synchronous d-axis voltage is diminished in proportion as reference voltage exceeds hexagon boundary. As a result, d-axis current is decreased in the overmodulation region, which improves the dynamic performance of torque control considering the current dynamics of induction motor. The conspicuous improvement of the proposed scheme over conventional ones is observed in experimental results.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1791-1801
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• 2016

This paper considers a carrier based signal injection method for use in the three shunt sensing inverter (TSSI) for sensorless motor control. It also analyzes the loss according to the injection axis of the voltage signal. To remove both the phase current and rotor position sensors, a sensorless method and a phase current reconstruction method can be simultaneously considered. However, an interaction between the two methods can be incurred when both methods inject voltage signals simultaneously. In this paper, a signal injection based sensorless method with the 120° OFF Discontinuous PWM (DPWM) is implemented in a TSSI to avoid this interaction problem. Since one leg does not have a switching event for one sampling period in the 120° OFF DPWM, the switching loss is altered according to the injection axis. The switching loss in the d-axis injection case can be up to 32% larger than that in the q-axis injection case. Other losses according to the injection axis are also analyzed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.9
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• pp.89-95
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• 2015

This paper presents a current sensorless maximum torque control of a synchronous reluctance motor drive. Stator current and current angle vs. maximum torque are obtained using measured d-axis and q-axis inductances. Then, d and q-axis stator voltage references for current sensorless maximum torque control are calculated from stator voltage equations. The proposed method is verified by simulation results comparing with conventional method.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.3
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• pp.361-366
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• 2012

This paper presents speed control of an electric motorcycle using a fuzzy controller. The electric motorcycle required to meet not only fast throttle response but also stability, when it is on a cruise. However, a 1.5KW (50cc) electric motorcycles selling in the current market are difficult to cruise under the following conditions which are occupant's weight, load weight, wind resistance and road conditions (dirt roads, asphalt road). Because of these reasons, the rapid speed changing occurs in uphill and downhill road. To solve these problems, The input value for Improved fuzzy controller use the speed error and error variance. The output value for improved fuzzy controller uses Q-axis of the motor controlled variable. The D-axis of the motor output for improved fuzzy control uses D-axis controlled variable in proportional to Q-axis controlled variable. Improved fuzzy controller drives the electric motorcycle equipped with IPMSM. The control subject used in this paper is a 1.5KW electric motorcycle equipped with improved fuzzy controller that was used to control the motor speed. To control IPMSM Type of motor torque, D, Q-axis current controller was used. The Fuzzy controller using the proposed algorithm is demonstrated by experimental hardware simulator.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.157-158
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.457-458
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• 2009

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.3
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• pp.133-140
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• 2006

This paper is proposed an efficiency optimization control algorithm for a synchronous reluctance motor(SynRM) which minimizes the copper and iron losses. Also, this paper presents a speed estimated control scheme of SynRM using artificial neural network(ANN). There exists a variety of combinations of d and q-axis current which provide a specific motor torque. The objective of the efficiency optimization controller is to seek a combination of d and q-axis current components, which provides minimum losses at a certain operating point in steady state. It is shown that the current components which directly govern the torque production have been very well regulated by the efficiency optimization control scheme. The proposed algorithm allows the electromagnetic losses in variable speed and torque drives to be reduced while keeping good torque control dynamics. The control performance of ANN is evaluated by analysis for various operating conditions. Analysis results are presented to show the validity of the proposed algorithm.