• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.8
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• pp.529-535
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• 2000

In this paper, a current control system of a single phase PWM AC/DC converter using a reduced-order Luenberger observer without source voltage sensors is proposed. The sinusoidal input current and unity input power factor are realised based on the estimated source voltage performed by the reduced-order Luenberger observer using actual currents and DC link voltage. The poles of the reduced-order Luenberger observer are placed in the left half plane of s-plane by the pole-placement method in order to acquire the stability of the observer. The magnitude and the phase of the estimated source voltage are used to accomplish the unity power factor. The proposed method is implemented by DSP(Digital Signal Processor). Experimental Results verify that the reduced-order observer estimates the source voltage without the estimation error and the control system accomplishes the unity power factor, and constant DC link voltage.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.400-402
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• 2007

This paper presents a vector control implementation for PMSM using Real Time Workshop and Embedded Target for TI C2000 DSP in MATLAB/SIMULINK. Speed, current and vector controllers are easily designed and implemented by using the MATLAB/SIMULINK program. Feedback of motor speed is processed through C28x QEP(Quadrature Encoder Pulse) block from encoder pulse. 3-Phase currents ares processed through C28x ADC block from current sensors. And gating signal of PWM inverter is generated through SVPWM and PWM block. Real-time program is drawn using SIMULINK and then converted program code for speed control of PMSM is downloaded into the TI eZdsp 2812 board. Experiments were carried out to examine validity of the proposed vector control implementation.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2042-2044
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• 2001

The jumping ring apparatus of the type described in this study is used to demonstrate and educate the effects of electromagnetic induction. Placing an aluminum ring over the core and switching on AC source causes the ring to jump in the air due to induced currents in the ring producing a magnetic field opposed to that produced in the core. If the AC current is slowly increased from zero or ring is placed over the core when AC is already flowing the ring floats due to the balance between its weight and the upward electromagnetic force. Pentimum computer is used to display this value to screen and generate control signal.

• Communications of the Korean Mathematical Society
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• v.27 no.2
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• pp.243-255
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• 2012

In this paper, we deal with an inverse problem for electrical resistor networks to detect the location of nodes where an extraordinary currents ow into or out of the nodes proportional to the potentials on them. To achieve the goal, we solve a special type of mixed boundary value problem for Laplace equations with potential terms on rectangular networks which plays a role as a forward problem. Then we solve an inverse problem to develop an algorithm to locate the node where the extraordinary current flows on it at most four times of measurements of potential and current on its boundary.

• Journal of Power Electronics
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• v.5 no.2
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• pp.151-159
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• 2005

The errors generated from current measurement paths are inevitable, and they can be divided into two categories: offset error and scaling error. The current data including these errors cause periodic speed ripples which are one and two times the stator electrical frequency respectively. Since these undesirable ripples bring about harmful influences to motor driving systems, a compensation algorithm must be introduced to the control algorithm of the motor drive. In this paper, a new compensation algorithm is proposed. The signal of the integrator output of the d-axis current regulator is chosen and processed to compensate for the current measurement errors. Usually the d-axis current command is zero or constant to acquire the maximum torque or unity power factor in the ac drive system, and the output of the d-axis current regulator is nearly zero or constant as well. If the stator currents include the offset and scaling errors, the respective motor speed produces a ripple related to one and two times the stator electrical frequency, and the signal of the integrator output of the d-axis current regulator also produces the ripple as the motor speed does. The compensation of the current measurement errors is easily implemented to smooth the signal of the integrator output of the d-axis current regulator by subtracting the DC offset value or rescaling the gain of the hall sensor. Therefore, the proposed algorithm has several features: the robustness in the variation of the mechanical parameters, the application of the steady and transient state, the ease of implementation, and less computation time. The MATLAB simulation and experimental results are shown in order to verify the validity of the proposed current compensating algorithm.

• Journal of Information Technology Applications and Management
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• v.26 no.6
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• pp.103-117
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• 2019

Demand for high power motors is rapidly increasing as the 4th industry and convergence technology has recently emerged. In order to produce high-strength permanent magnets, the magnets used for magnetization have been increased from DC 300V in the 1970s to DC 2.5kV in the 2010s, Up to DC 10kV in the 2030s, It is expected that higher voltage will be used to magnetize. However, in the case of a magnetizer using an existing electric signal control device, it is necessary to use a control device with a high-voltage insulation function in case a high voltage used for magnetization is leaked to the control device. If a short circuit accident occurs, the controller must be shut down and serious problems such as excessive repair costs arise. In this study, a control system adopting optical communication method instead of electric signal control method is proposed to prevent leakage currents in high-voltage magnetizer. We design a transmitter(Tx) and a receiver(Rx) device for the optical communication control device and implemented a prototype connecting the optical cable. In order to demonstrate the utility of high-voltage magnetizer using the optical communication control device, we analyzed the initial cost and the yearly cost for the years to analyze the net present value. As a result, In the case of the low-voltage magnetizer, the electric signal control method cost less, As the operating voltage of the magnetizer becomes higher. It is confirmed that it takes less cost when the optical communication control device is used.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.218-223
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• 1993

In this paper, we present a full digital control scheme which controls currents and speed of the permanent magnet AC servo motor with large range of bandwidth and high performance. The current equations of the permanent magnet AC servo motor are linearized by feedback linearization technique. Both acceleration feedforward terms and IP controllers, whose gains are functions of motor speed, are used in order to control motor currents. In addition the phase delays in current control loops are compensated by placing phase lead-lag compensators after current commands, which make it possible to avoid high gains in the current controllers. Unity power factor can be achieved by the proposed current controller. Pulsewidth modulation is performed by way of the well-known comparison with a triangular carrier signals. The velocity controller is designed on the basis of the linearized model of the permanent magnet AC servo motor by the proposed current controller. The performance of the entire control system is analyzed in the presence of uncertainty in the motor parameters. The proposed control scheme is implemented using the digital signal processor-based controller composed of an Analog Device ADSP 2111 and a NEC78310. The pulsewidth modulation (PWM) signals are generated through a custom IC, SAMSUNG-PWM1, which has the outputs of current controllers as input. The experimental results show that the permanent magnet AC servo motor can be always driven with high dynamic performance by the proposed full digital control scheme of motor speed and motor current.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.6
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• pp.514-524
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• 2001

Conventional average power theory has been used to design and control active power filters But compensating reference currents of active power filters calculated by conventional average power theory are definitively influenced by three phase source voltage conditions such as unbalance or distortion. This paper presents a new average power algorithm for active power filters which can detect symmetrically equally active or fundamental reactive currents in each phase based on decomposition of fundamental reactive component and harmonics under unbalanced power conditions. The effectiveness of the proposed algorithm is demonstrated by MATLAB/SIMULINK simulation and experimental results for a three wire distribution system with 15% unbalanced source voltages.

• Journal of the Korean Electrochemical Society
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• v.10 no.2
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• pp.150-154
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• 2007

Redox complexes to transport electrodes from biomaterial to electrodes are very important part in commercial biosensor industry. A novel osmium redox complex was synthesized by the coordinating pyridine group with osmium metal. A novel osmium complex is described as $[Os(dme-bpy)_2(ap-im)Cl]^{+/2+}$. We have been studied the electrochemical characteristics of this osmium complex with electrochemical techniques such as cyclic voltammetry and chronoamperommetry. In order to immobilize osmium redox complexes on the electrode, we deposited gold nano-particles on screen printed carbon electrode(SPE). The electrical signal converts the osmium redox films into an electrocatalyst for glucose oxidation. The catalytic currents were monitored that the catalytic currents were linearly increased from 1 mM to 5 mM concentrations of glucose.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.576-584
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• 2003

This paper presents a new control method of single-phase active power filter(APF) for the compensation of harmonic current components in nonlinear loads. Constructing a imaginary second-phase giving time delay to load currents, making single-phase system into the system that has two phases, complex calculation is possible. In the previous method, it made a imaginary-phase lagged to the load current T/4(here T is the fundamental cycle), but in proposed method, the new signal, which has the delayed phase through the filter, using the phase-delay property of low-pass filter, was used to the second phase. Instantaneous calculation of harmonic current is possible, because two phase have different phase. In this paper, it was done with instantaneous calculation using the rotating reference frames(RRF) that synchronizes with source-frequency, a reference of compensation currents, not applying to instantaneous reactive power theory which uses the existed fixed reference frames. The simulation and experiment about R-L loads using the current source were carried out, and the effect of the proposed method was preyed through the result of this experiment.