• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.4
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• pp.643-650
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• 2017

This pap4er analyzes resonance characteristics of a slave motor that is not controlled by load and parameter differences between Dual motors during parallel operation in middle-low speed. Dual SPMSMs(Surface mounted Permanent Magnet Synchronous Motor) connected in parallel to a single inverter controlled by the master and slave control in this paper. Based on the stability analysis of the SPMSM for a variation of torque angle, the 6th nonlinear state equation of the torque angle variation in the SIMM(Single Inverter Multi Motor) structure is derived according to a mathematical model for the dual motors. In general, an analysis of the 6th order nonlinear state equation is complex. Therefore, a resonance frequency generated from the slave motor is found from the characteristic equation of the 2nd order system obtained by linearization and model reduction near steady state operation point. Through simulations and experiments, it is confirmed that the stability analysis of the SPMSMs and state equation models are useful for the variation of the torque angle analyzed in this paper.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.47-50
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• 1997

The FEM(Finite Element Method) can be used to analysis SRM(Switched Reluctance Motor) as it can account for the salient pole geometry of the stator and rotor and the nonlinear properties of the magnetic materials. However, FEM requirers a lot of computer memory and computing time because, the kind of SRM drivers is verity and the switching strategies are various for one SRM driver. In this paper we proposed the method of analysis of a SRM which results are similar to FEM and has very short computing time. The Inductance and torque for each phase current at each rotor position are calculated by using two-dimensional nonlinear FEM analysis. Using the look-up table of inductance and torque and the voltage equations of SRM we obtained the phase current and torque. To verify proposed algorithm, 3 phase 6/4 SRM is analysed and found a good agreement with FEM results. And computing time is about 1/1600 of the FEM analysis.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.2
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• pp.81-87
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• 1996

Time delay control(TDC) law has been recently suggested as an effective control technique for nonlinear time-varying systems with uncertain dynamics and/or unpredictable disturbances. This paper focuses on the applications of the TDC algorithm to torque control of an engine system and speed control of an engine/automatic transmission system. Through the stability analysis of the engien system based on TDC, determination of the appropriate time delay and control factor is investigated. It was revealed that the size of time delay of the TDC law should be greater than that of transport delay of the system for both stability and better control performance. Simulation and experimental results for the engine torque control and engine/automatic transmission speed control systems show both relatively good command following and disturbance rejection properties. However, TDC controller shows rather slow responses when applied to the system with large transport delay.

• The Journal of Korea Robotics Society
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• v.13 no.3
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• pp.157-163
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• 2018

This paper deals with the development and application of control algorithms for series elastic relief robots for rescue operations in harsh environment like disasters or battlefield. The joint controller applied in this paper has a cascade structure combining inner loop for torque control and outer loop for position control. The torque loop contains feedforward and feedback controller and disturbance observer for independent, decentralized joint control. The effect of the elastic component and motor dynamics are treated as the nonlinear disturbance and compensated with the disturbance observer of torque controller. For the collision detection, Band Designed Disturbance Observer is configured to recognize/respond to external disturbance robustly in the continuously changing environment. The controller is applied to a 7-dof series elastic manipulator to evaluate the torque tracking and collision detection/response performance.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.373-375
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• 2004

The SRM is more robust and lower cost than other type motors. The inverter for SRM cannot have shoot through fault, since a phase winding of SRM is independent of other phase windings. The SRM has high starting torque and high power density. But it has torque ripples due to nonlinear magnetic characteristics. Therefore, SRM has highly non-linear torque producing characteristics. Because fuzzy logic is a flexible and general-purposed method for implementing non-linear dynamic functions, it is effective for the control of high current SRM. We design the fuzzy controller and demonstrate the fuzzy control system by MATLAB.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.514-518
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• 2005

In this paper an adaptive fuzzy PI controller with feedback linearizing meth od is implemented to controlling flux and torque separately in induction motor. In this paper first decoupling of torque and flux which are outputs to be controlled, is achieved by using feedback linearization methodology. Then for reducing the effect of noise and rejection of disturbance, main part of controller which is adaptive PI fuzzy controller, is designed. Coefficients of PI controller are determined by defined fuzzy rules due to error dynamic. Inputs of fuzzy system are defined sliding surfaces which consist of torque and flux errors. The main contribution of this paper is effect reduction of noise and disturbance on torque and flux which is based on fuzzy logic and nonlinear control. At last the effectiveness of the proposed control scheme in presence of noise and load disturbance is simulated and comprised to applying sliding method. The results verify better effectiveness of the proposed method for effect reduction of noise and disturbance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.202-205
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• 2008

This paper presents an optimization of permanent magnet (PM) in a brushless dc (BLDC) motor using the response surface methodology (RSM). Size and angle of the PM are optimized to minimize the cogging torque, while reducing the magnitude of harmonic at a dominant frequency and maintaining the operating torque. A fitted RS model is constructed by verifying the high reliability of the total variation and the variation of estimated error. The optimized design is validated by carrying out the reanalysis and comparing to the initial model using the nonlinear transient finite element analysis.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.159-161
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• 1997

This paper presents a method of reducing cogging torque and improving average torque by changing the dead zone angle of trapezoidal magnetization distribution of rotor magnet in ring type. Because brushless d.c. motor has 3D shape of overhang, 3D analysis should be used for computation of its magnet field. In this paper, Three Dimensional Equivalent Magnetic Circuit Network method (3DEMCN) which can calculate an accurate 3D magnetic field has been introduced. The method has an advantage that nonlinear magnetic phenomena can be considered and the cogging torque analyses requesting the rotation of the rotor can be performed by the variation of magnetization distribution without remesh.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.1
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• pp.6-12
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• 2007

In this paper, an robust adaptive backstepping controller is proposed for the speed control of separately excited DC motor in pure electric vehicles. A general electric drive train of PEV is conceptually rearrange to major subsystems as electric propulsion, energy source, and auxiliary subsystem and the load torque is modeled by considering the aerodynamic, rolling resistance and grading resistance. Armature and field resistance, damping coefficient and load torque are considered as uncertainties and noise generated at applying load torque to motor is also considered. It shows that the backstepping algorithm can be used to solve the problems of nonlinear system very well and robust controller can be designed without the variation of adaptive law. Simulation results are provided to demonstrate the effectiveness of the proposed controller.

• The KSFM Journal of Fluid Machinery
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• v.15 no.2
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• pp.36-40
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• 2012

Pitch control of wind turbine is activated above rated wind speed for the purpose of rated power regulation. When we design pitch controller, its gain-scheduling is essential due to nonlinear characteristics of aerodynamic torque. In this study, 2-mass model including a vibration mode of drive-train for a 2 MW wind turbine is considered and pitch control with gain-scheduling using a linearization analysis of the nonlinear aerodynamic torque is applied. Some simulation results for the pitch gain-scheduling under step wind speed are presented and investigated. It is shown that gain-scheduling in pitch control is important especially in the region of high wind speeds when there exists a vibration mode of drive-train.