• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1515-1522
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• 2011

This paper proposes the algorithm for the output AC voltage control of Z-source inverter by the detection of the input DC voltage and Z-network capacitor voltage. The actual modulation index of the proposed method is detected by the capacitor voltage in Z-network and input DC voltage of three-phase Z-source inverter. Control modulation index for the output voltage control is calculated by the detected actual modulation index and reference modulation index. And, calculated control modulation index is applied to the modified space vector modulation (SVM) for control the output voltage of Z-source inverter. To verify the validity of the proposed method, PSIM simulation was achieved and a DSP controlled 1[kW] three-phase Z-source inverter was producted. The simulation and experiment were performed under the condition that the load was changed in case of the constant input DC voltage and the input DC voltage was changed in case of the load was constant. As a result, we could know that the output phase voltage of Z-source inverter followed to the reference voltage 70[VRMS] despite the load or the input DC voltage were suddenly changed.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.107-109
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• 2003

Single phase induction motor is directly used usual source, it can be a source of an appliance such as mechanical fan, refrigerator, washing machine, etc. Especially capacitor-run single phase induction motor is suitable to make more inexpensive and high efficient products because it is more high efficiency, and good to start than other single phase induction motors. Generally, voltage and current of capacitor-run single phase induction motor transfer to the part of positive phase and negative phase based on two motor theory. In this paper, we simulate the torque characteristics to capacitance variation from single phase induction motor's equivalent circuit. Through the test using the real motor, we compare and investigate the maximum torque of run state related with capacitance and the adequacy of the converted model.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.3
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• pp.275-284
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• 1999

Unbalanced source voltage in the 3-phase power system is decomposed into positive, negative and zero sequence c components. Also, assuming there is no neutral path in the system, the zero sequence component is not shown on the l load side. Therefore, in the unbalanced power system without neutral path. it is possible to provide balanced voltage to t the load side by compensating negative sequence component and also to regulate the voltage amplitude by controlling t the positive sequence component. In addition, the symmetrical components due to voltage unbalance can be effectively d detected on the synchronous reference frame by using dlongleftarrowq transformation. In this paper, an algorithm not only c compensating unbalanced source voltage by canceling the negative sequence component on the synchronous reference f frame but also maintaining load voltages constantly is proposed. Also a novel method for phase angle detection s synchronized by positive sequence component under unbalanced source voltage is suggested and this detected phase a angle is used for d-q transformation. The performances and characteristics of the proposed compensating system are a analyzed by simulation and verified through experimental results.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.135-138
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• 2006

For compensating the a.c voltage variations of single-phase micro-source, micro-source system with a voltage compensator is proposed. Single phase p-q algorithm for calculating the a.c voltage variations of the micro-source is used. The effectiveness of the proposed the system is verified by the PSIM simulation in the steady state and transient state.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.155-158
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• 2000

A new control method for single-phase shunt active power line conditioners(APLC's) operated under zero average power consumption is proposed in this paper. The amplitude of the sinusoidal source current which is in-phase with the source voltage can be determined from the average value of the instantaneous load power. Then the command current for the shunt APLC is obtained by subtraction the source current from the load current. Neither bulky filter nor time-consuming computation is required. The shunt power compensator supplies all the harmonics of he load current and the source only supplies the fundamental component,. Experimental results on a prototype verify the feasibility of the presented scheme,

• 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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• 2014.07a
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• pp.301-302
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• 2014

This paper describes four switch three-phase Z-source rectifier with improved switching characteristics. This configuration has some advantages switching loss and optimal drive circuit. The rectifier has buck-boost function by shoot-through state. Also, the rectifier has the advantage of decreasing inrush current in start-up and transient states. In order to reduce harmonics PWM modulation technique with a variable index has been suggested. Four switch three-phase Z-source rectifier with improved switching characteristics can output stable DC voltage at the same time decreasing the system's harmonic current. And also the paper presents an application of DCC method in Z-source rectifier. Principles and dynamics of the system are discussed in detail. After having viewed the results we can confirm that the proposed method is eligible and efficient.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.637-640
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• 2005

We propose a sound source localization method using the Head-Related-Transfer-Function (HRTF) to be implemented in a given platform. HRTFs contain not only the information regarding proper time delays but also phase and magnitude distortions due to diffraction and scattering by the shading object. Therefore, a set of HRTFs for any given platform provides a substantial amount of information as to the whereabouts of the source. In this study, we introduce new phase criterion in order to find the sound source location in accordance with the HRTF database empirically obtained in an anechoic chamber with the given platform. Using this criterion, we analyze the estimation performance of the proposed method in a household environment.

• Journal of Power Electronics
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• v.17 no.1
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• pp.190-199
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• 2017

In this paper, a predictive direct power control (DPC) method based on a Kalman filter is presented for three-phase pulse-width modulation (PWM) rectifiers to improve the performance of rectifiers with source voltages that are distorted with harmonic components. This method can eliminate the most significant harmonic components of the source voltage using a Kalman filter algorithm. In the process of predicting the future real and reactive power to select an optimal voltage vector in the predictive DPC, the proposed method utilizes source voltages filtered by a Kalman filter, which can mitigate the adverse effects of distorted source voltages on control performance. As a result, the quality of the source currents synthesized using the PWM rectifier is improved, and the total harmonic distortion (THD) values are reduced, even under distorted source voltages.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.5
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• pp.258-264
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• 2006

This paper presents an integrative control scheme for series-type active power filters combined with shunt passive filters not only to compensate for the source voltage unbalance and current harmonics but also to correct the power factor. To reduce the power capacity of the active filters, passive filters are connected in parallel. Diode rectifiers are replaced by the PWM converters in order to feed the real power back to the source. Power factor control is performed by changing the phase of the load voltage so that the phase of the source current coincides with that of the source voltage. The resultant voltage reference is the addition of the voltage component compensating for the source voltage unbalance and harmonic currents and the voltage component correcting the power factor. The validity of the proposed algorithm has been verified by experimental results.