• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.138-144
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• 2000

Robot manipulators, which are nonlinear structures and have uncertain system parameters, have complex in dynamics when are operated in unknown environment. To compensate for estimate errors of the uncertain system parameters and to accomplish the desired trajectory tracking, nonlinear robust controllers are appropriate. However, when estimation errors or tracking errors are large, they require large input torques, which may not be satisfied due to torque limits of actuators. As a result, their stability can not be guaranteed. In this paper, a new robust control scheme is presented to solve stability problem and to achieve fast trajectory tracking in the presence of torque limits. By using fuzzy logic, new desired trajectories which can be reduced are generated based on the initial desired trajectory, and torques of the robust controller are regulated to not exceed torque limits. Numerical examples are shown to validate the proposed controller using an uncertain two degree-of-freedom underwater robot manipulator.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.171-174
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• 1999

The torque of SRM is developed by phase currents and inductance variation. Phase currents and inductance variation. Phase current is often the controlled variable in electrical motor drives, so it seems natural to use closed loop current controllers. However, the highly nonlinear nature of switched reluctance motors makes optimisation of closed loop current controlled difficult because of saturation effect in magnetic circuit. Therefore, torque generation region is nonlinearly varied according to phase current and rotor position. This paper describes the torque control scheme with neural network that can control varied with load torque. The torque control is simulated by PSIM.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2391-2395
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• 2009

Active control schemes which modify the excitation to correct for any of the nonideal characteristics of the SPMSM is described. Especially, because of design limitations(size and cost) in automobile, the back-EMF of SPMSM can't be perfectly designed with sinusoidal wave and iron core of stator is saturated so that torque ripple is unavoidable. An active cancellation method of the pulsating torque components which would otherwise be generated using the classic sinusoidal current excitation is illustrated.

• Journal of Power Electronics
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• v.18 no.4
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• pp.1099-1110
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• 2018

In this paper, a loss minimization control method for interior permanent magnet synchronous motors is presented with considering self-saturation and cross saturation. According to variation of the d-axis and q-axis inductances by different values of the d-axis and q-axis components of currents, it is necessary to consider self-saturation and cross saturation in the loss minimization control method. In addition, the iron loss resistance variation due to frequency variation is considered in the condition of loss minimization. Furthermore, the loss minimization control method is compared with maximum torque per ampere (MTPA), unity power factor (UPF) and $i_d=0$ control methods. Experimental results verify the performance and proper dynamic response of the loss minimization control method with considering self-saturation and cross saturation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.3
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• pp.430-438
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• 2019

For a pump or a compressor motor, a high periodic load torque variation is induced by the mechanical works, and it causes system vibration and noise. To minimize these problems, load torque compensation method, injecting periodic torque current, could be utilized. However, with the sensorless control method, which is usually utilized in the pump and compressor for low cost, the periodic torque current degrades the accuracy of the rotor position estimation owing to the inductance variation. This paper analyzes the rotor position and speed estimation error of sensorless control method with constant motor parameters under period loading. Assuming the constant speed by the accurate load torque compensation, the speed error equation is derived in frequency domain with inductance depending on the stator current. Further, it is also shown that the rotor position error could be minimized by compensating the inductance variation. The simulation and experimental results verify that the derived speed error model and the validity of the inductance compensation method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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• pp.1209-1217
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• 1997

This paper proposes the modeling of the dynamics of two cooperating robot manipulators performing the assembly job such as peg-in-hole while coordinating the payload along the desired path. The mass and moment of inertia of the manipulators and the payload are assumed to be unknown. To control the uncertain system, a robust control algorithm based on the computed torque control is proposed. Usually, the robust controller requires high input torques such that it may face input saturation in actual application. In this reason, the robust control algorithm includes fuzzy logic such that the magnitude of the input torque of the manipulators is controlled not to go over the hardware saturation while keeping path tracking errors bounded. A numerical example using dual three degree-of-freedom manipulators is shown.

• Journal of Power Electronics
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• v.11 no.4
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• pp.418-423
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• 2011

This paper presents a simulation model and a parameter identification scheme of an induction motor drive for electric vehicle. The induction motor in automotive applications should operate in very high efficiency and achieve the maximum-torque-per-ampere (MTPA) feature even with saturated magnetic flux under very high torque. The indirect vector control which is typically adopted in traction drive system requires precise information of motor parameters, particularly rotor time constants. This work models an induction motor considering magnetic saturation and proposes an empirical identification method using the current controller in the synchronous reference frame. The proposed method is applied to a 22kW-rated induction motor for electric vehicle.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.5
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• pp.388-395
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• 2016

Electric vehicles (EV) and hybrid EVs (HEV) are designed and manufactured by GM, Toyota, Honda, and Hyundai motors. The propulsion system design process for EV requires integrating subsystem designs into an overall system model to maximize the performance of a given propulsion architecture. Therefore, high-power density and high-torque density are important attributes required for EV applications. To improve torque and power density, propulsion motors are designed for saturation during high-torque operation. The nonlinearity associated with core saturation is modeled by incorporating the cross-coupling inductances, which also behave nonlinearly. Furthermore, in EV environments, the battery is directly connected to the DC link, and the battery changes depending on the state of charge. It will be onerous if as many optimal current commands as different $V_{dc}$ were made. This paper presents the optimal current commands in the various operating condition and the current control technique in EV environments.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.667-668
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• 2015

Synchronous Reluctance Motor (SynRM) has a simple structure with high efficient and without rotor conductor loss. Therefore, it is better than induction motor for electric vehicle (EV) on aspect of efficiency. SynRM usually operates on the constant torque region using maximum torque per ampere （MTPA）control which is adopted due to rotor structure limitation. Thus, the accurate current angle is crucial for motor control. However, finite element analysis (FEA) program is not sufficient exactly to regard how the iron loss and magnetic saturation influences on the current angle. Consequently, this paper proposed a method to calculate the current angle with consideration of iron loss.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.148-153
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• 1988

In this study, the stabilization of moving sight using a gyro is investigated. At first, Linear Compensator was design by linearizing gyro, torque motor and several parameters from a given required frequency response curve. By using this, System Control Performance was analyzed by back EMF, torque saturation and Coulomb friction effects. Also stabilization Performance by disturbances and Paramter variations were simulated.