• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.240-246
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• 2018

In this paper, a sensorless V/f control based on maximum torque per ampere (MTPA) operation for PMSMs is proposed. Given that the MTPA operation is not considered in the conventional sensorless V/f control, efficient PMSM drives cannot be achieved. Therefore, this paper proposes an improved technique based on the d-axis current control to enable the MTPA operation in the V/f control for PMSMs. A stabilization technique is also proposed to improve the dynamic characteristics and stability against load variation. The effectiveness of the proposed technique is verified by conducting experiments with a 250 W SPMSM for driving a blower.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1166-1176
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• 2017

Estimation errors of the rotor speed and position in sensorless control systems of Permanent Magnet Synchronous Motors (PMSM) will lead to low efficiency and dynamic-performance degradation. In this paper, a parallel-type extended nonlinear observer incorporating the nominal parameters is constructed in the stator-fixed reference frame, with rotor position, speed, and the load torque simultaneously estimated. The stability of the extended nonlinear observer is analyzed using the indirect Lyapunov's method, and observer gains are selected according to the transfer functions of the speed and position estimators. Taking into account the parameter inaccuracies issue, explicit estimation error equations are derived based on the error dynamics of the closed-loop sensorless control system. An equivalent flux error is defined to represent the back Electromotive Force (EMF) error caused by the inaccurate motor parameters, and a compensation strategy is designed to suppress the estimation errors. The effectiveness of the proposed method has been validated through simulation and experimental results.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.1
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• pp.89-97
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• 2008

Chaotic behavior in motor systems is undesired dynamics in real-time implementation since the speed is oscillated in a wide range and the torque is changed by a random manner. We present an adaptive control approach for time-varying permanent-magnet synchronous motors (PMSM) with chaotic phenomenon. We consider that its parameters are changed randomly within certain bounds. First, a nonlinear system model of a PMSM is transformed to derive a nominal linear control strategy. Then, an auxiliary control for compensating real-time control error occurred by system perturbation due to parameter change is designed by using Lyapunov stability theory. Numerical simulation is accomplished for evaluating its efficiency and reliability comparing with the traditional control method. Additionally, we test our control method in real-time motor experiment including a PSoC based drive system to demonstrate its practical applicability.

• Journal of the Semiconductor & Display Technology
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• v.6 no.1 s.18
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• pp.31-36
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• 2007

Effect of coulomb friction and backlash on the single loop position control has been studied for the precision position control. We have showed the limit cycle on the single loop system which used a ball screw that had the backlash. Also, we have made an inner loop with a classical velocity and torque controller which was forcing the current of d axis to be zero by using a permanent-magnet synchronous motor and composed the outer loop with linear encoder for sensing a position of the loader. Also, we have used least squares fit(LSF) observer for reducing noise when we got velocity from position outputs. We have shown a good result by using the dual loop through simulation and experiment.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.13-15
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• 2007

The washing machine needs high torque for large load variation, Interior permanent magnet synchronous motor(IPMSM) is proper to adapt the washing machine system. However, IPMSM can operate the lower output power than the other permanent magnet synchronous motor(PMSM) when the motor control by the conventional control. This paper suggests adaptive motor control for IPMSM and experiments the washing machine system.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.92-94
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• 2005

Speed and torque controls of permanent magnet synchronous motors are usually attained by the application of position and speed sensors. However, speed and position sensors require the additional mounting space, reduce the reliability in harsh environments and increase the cost of a motor. Therefore, many studios have been performed for the elimination of speed and position sensors. This paper investigates a novel speed sensorless control of a permanent magnet synchronous motor. The proposed control strategy compensates a speed error through the difference between the calculated and measured reactive power. The proposed algorithm is verified through the simulation and experimentation.

• Journal of IKEEE
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• v.21 no.3
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• pp.174-184
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• 2017

This paper proposes a torque predictive control for dynamic performance improvement of clamping force in electro-mechanical brake (EMB) for railroad cars. In general, pneumatic braking system (PBS) is used for railroad cars. It is sensitive depending on environmental changes and it has increasing idle running time because of slow dynamic response. Additionally, the PBS has low braking efficiency in case braking torque more than standard value is applied to the brake system such as emergency braking. In order to overcome these disadvantages of the PBS, the EMB is used for the railroad cars. The EMB for railroad cars has advantages that increasing the fuel efficiency and design flexibility because it is able to decrease vehicle weight of railroad cars and secure space for design. In this paper, control method for dynamic performance improvement of clamping force in EMB for railroad car is proposed. The effectiveness of the proposed control method is verified by the simulation results.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.99-100
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• 2016

In a AC motor used by three phase inverter, the phase current must be measured to control instantaneous torque. It is expensive to use current sensor for measuring current in low cost motor. So, shunt resistor is used to measure current. But, the method sensing the phase current using shunt resistor cannot perform the vector control in high speed because of the area that impossible to restore three phase current. In this paper, predictive current is proposed for reconstructing the current in the impossible current sensing area that reduce the current ripple in TSSI(Three shunt sensing inverter) for PMSM.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.127-132
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• 2022

Among the electrical components mounted on railroad cars, the largest load is the main transformer, which has a low power density of 0.2~0.4 MVA/ton due to the low operating frequency(60Hz), which is an important factor for weight reduction. Therefore, research on molded transformers, semiconductor transformers, etc. is being actively conducted at Domestic and foreign in order to improve the main transformer for railway vehicles. Meanwhile, attempts are being made to apply a permanent magnet synchronous motor (PMSM) to replace an induction motor as a traction motor that is mostly applied to domestic and foreign railway vehicles. Permanent magnet synchronous motors (PMSMs) can secure higher power density and efficiency compared to induction motors, but have disadvantages in that the materials required for manufacturing are expensive and design is somewhat difficult compared to induction motors. Considering these problems, in this paper, we suggest that a small and lightweight semiconductor transformer is applied, and a simple structure, high torque, low cost SRM can be applied in accordance with the requirements such as weight reduction and high efficiency of railroad vehicles. content.

• Journal of Power Electronics
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• v.2 no.3
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• pp.220-229
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• 2002

In this paper, maximum efficiency operation of two types of permanent magnet synchronous motor drives, namely; surface type permanent magnet synchronous machine (SPMSM) and interior type permanent magnet synchronous motor(IPMSM), are investigated. The efficiency of both drives is maximized by minimizing copper and iron losses. Loss minimization is implemented using flux weakening. A neural network controller (NNC) is designed for each drive, to achieve loss minimization at difffrent speeds and load torque values. Data for training the NNC are obtained through off-line simulations of SPMSM and IPMSM at difffrent operating conditions. Accuracy and fast response of each NNC is proved by applying sudden changes in speed and load and tracking the UC output. The drives'efHciency obtained by flux weakening is compared with the efficiency obtained when setting the d-axis current component to zero, while varying the angle of advance "$\vartheta$" of the PWM inverter supplying the PMSM drive. Equal efficiencies are obtained at diffErent values of $\vartheta$, derived to be function of speed and load torque. A NN is also designed, and trained to vary $\vartheta$ following the derived control law. The accuracy and fast response of the NN controller is also proved.so proved.