• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2301-2309
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• 2018

In a field-oriented vector-controlled permanent magnet synchronous motor (PMSM) control system, the d-axis current control loop can offer a free degree of freedom which can be used to improve control performances. However, in the industry the desired d-axis current command is usually set as zero without using the free degree of freedom. This paper proposes a method to use the degree of freedom for control performance improvement. It is assumed that both the inner loop proportional-integral (PI) current controller and the q-axis outer loop PI speed controller are tuned by the well-known tuning rules. This paper gives an optimal d-axis reference current command generator such that some useful performance indexes are minimized and/or a tradeoff between conflicting performance criteria is made. This paper uses a differential evolution algorithm to autotune the parameter values of the optimal d-axis reference current command generator. This paper implements the proposed control system in real time on a Texas Instruments TMS320F28335 floating-point DSP. This paper also gives experimental results showing the practicality and feasibility of the proposed control system, along with simulation results.

• 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.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1159-1167
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• 2011

A novel 3D tube scanning technique is proposed. The proposed tube scanning technique is developed for a special tube inspection module which consists of four line-lasers and one camera. Using the scanning module, we can reconstruct the 360 degree shapes of the inner surfaces of a cylindrical tube. From an image frame captured by the camera, we reconstruct a partial tube model based on four laser triangulations. Then by aligning such partial models with respect to a reference tube axis, a complete 3D shape of the tube is reconstructed. The tube axis in each reconstructed frame is aligned with a 3D Euclidean transformation to the reference axis. Several experiments show that the proposed method can align multiple tube axes very accurately and reconstruct 3D shapes of a tube with very low shape distortion.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1245-1248
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• 2004

This paper presents a new technique to analyze data on the coordinate x, y, z and apply these data to design the motion control to improve the efficiency of the engraving machine so that it can engrave accordingly in 3 dimensions. First, the tool path on the x-y plane is analyzed to be synchronized with the z-axis. The digital data is then sent to the motion control to guide the movement of the engrave point on the x-y plane. Tool path moves along the x-axis with zero degree and different values of the y-axis according to the coordinate of the digital data and the analysis along z-axis to determine the depth for engraving. The depth can be specified from the gray level with the 256 levels of resolution. The data obtained includes the distances on x-axis, y-axis, and z-axis, the acceleration of the engrave point's movement, and the speed of the engrave point's movement. These data is then transfered to the motion control to guide the movement of the engrave point along the z-axis associated with the x-y plane. The results indicate that engraving using this technique is fast and continuous. The specimen obtained looks perfect in 3D view.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.880-882
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• 1995

The systematic function of the PLC (Programmable - Logic Controller) has been enhanced immensely due to the various special modules that consist of the conventional I/O control contants plus special function, which enables the flexible application to highly advanced systems. Position control module is one of the various PLC special module. In this paper, we proposed new synchronized operating method and implemented 8 - axis servo control system. The validity of proposed method is verified througth experimental results and it will be possible to expand 32 - axis servo control system by RS - 485 communication spec.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1515-1527
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• 2018

This paper presents a sensorless speed control of IPMSM (Interior Permanent Magnet Synchronous Motor) using the high-frequency (HF) square wave injection method. In the proposed HF pulsating square wave injection method, injection voltage is applied into the estimated d-axis of rotor and high-frequency induced q-axis current is considered to estimate the rotor position. Conventional square wave injection methods may need complex demodulation process to find rotor position, while in the proposed method, an easy demodulation process based on the rising-falling edge of the injected voltage and carrier induced q-axis current is implemented, which needs less processing time and improves control bandwidth. Unlike some saliency-based sensorless methods, the proposed method uses maximum torque per ampere (MTPA) strategy, instead of zero d-axis command current strategy, to improve control performance. Furthermore, this paper directly uses resultant d-axis current to detect the magnet polarity and eliminates the need to add an extra pulse injection for magnet polarity detection. As experimental results show, the proposed method can quickly find initial rotor position and MTPA strategy helps to improve the control performance. The effectiveness of the proposed method and all theoretical concepts are verified by mathematical equations, simulation, and experimental tests.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.397-404
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• 2004

This paper proposes a variable speed control scheme of grid-connected wind power generation systems using cage-type induction generators. The induction generator is operated in indirect vector control mode, where the d-axis current controls the excitation level and the q-axis current controls the generator torque, by which the speed of the induction generator is controlled according to the variation of the wind speed In order to produce the maximum output power. The generated power flows into the utility grid through the back-to-back PWM converter. The line-side converter controls the dc link voltage by the q-axis current control and can control the line-side power factor by the d-axis current control. Experimental results are shown to verify the validity of the proposed scheme.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.9
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• pp.1165-1173
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• 2018

Recently, owing to environmental problems and instability of rare earth resources market, non-rare earth electric motors are attracting attention. As a non-rare earth motor type, a wound rotor synchronous motor(WRSM) has high power density and wide driving range further it can reduce loss by field current control during field weakening control at high speed. However, since the d-axis flux of the WRSM is coupled with the rotor circuit, the fluctuation in the d-axis flux linkage affects the rotor circuit, which causes ripple of the field current and torque. In this paper, we propose the field current ripple compensation method by injecting the feedforward voltage. the proposed compensating method was demonstrated by simulation and experiments.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.8
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• pp.361-366
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• 2001

This thesis proposes a fuzzy logic cross coupled controller for a multi axis servo system. The overall control system consists of three elements: the axial position controller, the speed controller, and a fuzzy logic cross coupled controller. In conventional multi axis servo system, the motion of each axis is controlled independently without regard to the motion of other axes, in which the contour error, defined as the shortest distance between the desired and actual contours is compensated only by the position error of each axis. This decoupled control approach may result in degraded contouring performance due to such factors as mismatch of axial dynamics and axial loop gains. In practice, such systems contain many uncertainties, Therefore, the multi axis servo system must receive and evaluate the motion of all axes for a better contouring accuracy. Cross coupled controller utilizes all axis position error information simultaneously to produce accurate contours. However the existing cross coupled controllers cannot overcome friction, backlash and parameter variation. Also, since it is difficult to obtain an accurate mathematical model of multi axis system, here we investigate a fuzzy logic cross coupled controller method. Some simulations and experimental results are presented to illustrate the performance of the proposed controller.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.4
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• pp.586-593
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• 1994

This paper suggests the algorithm for on-line efficiency control of permancent magnet synchronous motors driving the electric vehicles. The existance of unigue d-axis current is verified, which generates the maximum efficiency at operating points of motor. Using the Fibonacci search method, d-axis current converges to the minimization of inverter input power, and to prevent the variation of motor speed in process of the efficiency control, the voltage decoupled control strategy is introduced. Through the experiments, the effects of an efficiency control algorithm are verified.