• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1241-1250
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• 2018

Parallel three-phase voltage source inverters in a direct connection configuration are widely used to increase system power ratings. A zero-sequence circulating current can be generated according to the switching method; however, the zero-sequence circulating current not only distorts current, but also reduces the system reliability and efficiency. In this paper, a model predictive control scheme is proposed for parallel inverters to drive an interior permanent magnet synchronous motor with zero-sequence circulating current suppression. The voltage vector of the parallel inverters is derived to predict and control the torque and stator flux components. In addition, the zero-sequence circulating current is suppressed by designing the cost function without an additional current sensor and high-impedance inductor. Simulation and experimental results are presented to verify the proposed control scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.4
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• pp.347-355
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• 2005

In this paper, a new continuous~time small signal model of an average current mode control is proposed. Sampling effect Is considered to obtain the proposed small signal model. By the proposed model, the high frequency response characteristics of current loop gain might be predicted accurately compared to previous models. And this leads the prediction of inductor current response of the proposed model to be accurate compared to others. In order to show the usefulness of the proposed model, prediction results of the proposed model are compared to those of the circuit level simulator, PSIM and experiment.

• Journal of the Korea Society for Simulation
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• v.4 no.2
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• pp.41-60
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• 1995

The IGBT(Insulated Gate Bipolar Transistor) is a power semiconductor device that has gained acceptance among circuit design engineers for motor drive and power converter applications. IGBT devices(International Rectifier, Proposed proposed model etc) have the best features of both power MOSFETs and power bipolar transistors, i.e., efficient voltage gate drive requirememts and high current density capability. When designing circuit and systems that utilize IGBTs or other power semiconductor devices, circuit simulations are needed to examine how the devices affect the behavior of the circuit. The interaction of the IGBT with the load circuit can be described using the device model and the state equation of the load circuit. The voltage rise rate at turn-off for inductive loads varies significantly for IGBTs with different base life times, and this rate of rise is important in determing the voltage overshoot for a given series resistor-inductor load circuit. Excessive voltage overshoot is potentially destructive, so a snubber protection circuit may be required. The protection circuit requirements are unique for the IGBT and can be examined using the model. The IGBT model in this paper is verified by comparing the results of the model with experimented results for various circuit operating conditions. The model performs well and describes experimented results accurately for the range of static and dynamic condition in which the device is intended to be operated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.607-610
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• 2003

The characteristic prediction and analysis of 3-dimensional (3-D) solenoid-type embedded inductors is investigated. The four different structures of 3-D inductor are fabricated by using low-temperature cofired ceramic (LTCC) process. The circuit model parameters of the each building block are optimized and extracted using the partial element equivalent circuit method and HSPICE circuit simulator. Based on the model parameters, predictive modeling is applied for the structures composed of the combination of the modeled building blocks. And the characteristics of test structures, such as self-resonant frequency, inductance and Q-factor, are analyzed. This approach can provide the characteristic conception of 3-D solenoid embedded inductors for structural variations.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.541-543
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• 2002

This paper describes the analysis resulates on the P.T ferroresonance at 154kV GIS(Gas Insulated Substation) by EMTP(Electromagnetic transient program). We had simulated the PT ferroresonance between a potential transformer(PT) and open circuit braker's grading capacitance. The ferroresonance leads to very large power frequency overvoltage on PT bus and subsequent insulation failure. The damping circuit connected on the secondary winding were considered in the model. The actual countermeasure include a saturable inductor and a resistor series mounted, but the 2 ohms of damping resistance was used in the computational model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.216-221
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• 2000

This paper describes the analysis results on the PT ferroresonance at 154 kV GIS (gas Insulated substation by EMTP(Electro- magnetic Transient Program). We had simulated the PT ferroresonance between a potential transformer(PT) and an open circuit breaker's grading capacitance. The ferroresonance leads to very large power frequency overvoltages on PT bus and subsequent insulation failure. The large power can be supplied to the PT by the high voltage on the opened circuit due to the grading capacitance and equivalent capacitance of the buses during the ferroresonance. The damping circuit connected on the secondary winding were considered in the model. The actual countermeasure include a saturable inductor and a resistor series-mounted, but the 2 ohms of damping resistance was used in the computationl model.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2076-2079
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• 1999

This paper describes the analysis results on the PT ferroresonance at 154 kV GIS (gas Insulated substation by EMTP (Electro-magnetic Transient Program). We had simulated the PT ferroresonance between a potential transformer(PT) and an open circuit breaker's grading capacitance. The ferroresonance leads to very large power frequency overvoltages on PT bus and subsequent insulation failure. The large power can be supplied to the PT by the high voltage on the opened circuit due to the grading capacitance and equivalent capacitance of the buses during the ferroresonance. The damping circuit connected on the secondary winding were considered in the model. The actual countermeasure include a saturable inductor and a resistor series-mounted, but the 2 ohms of damping resistance was used in the computational model.

• Journal of Industrial Technology
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• v.18
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• pp.323-328
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• 1998

A current controlled VSI-PWM rectifier and inverter with capacitor dc link is regarded as one of the most promising structures for three-phase to three-phase to three-phase power conversion. This type of converter normally requires twelve switches for a rectifier and inverter composed of self turn-off switch such as a bi-polar transistor or IGBT with an anti-parallel diode. In this paper, a new three-phase to three-phase converter for ac motor drives is proposed. The proposed converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow. This paper describes the feasibility and the operational limitations of the proposed structure. A mathematical model of the system is derived using generalized modulation theory and experimental results for steady state and dynamic behavior are presented to verify the developed model.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.2
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• pp.149-155
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• 2012

This paper provides an efficient model predictive control for the output voltage control of three-phase inverter system which includes output LC filters. Use of SVPWM (Space Vector Pulse-Width-Modulation) and the rotating d-q frame is made to obtain an input constrained dynamic model of the inverter system. From the measured/estimated output current and reference output voltage, corresponding equilibrium values of the inductor current and the control input are computed. Derivation of a feasible and invariant set around the equilibrium state is made and then a receding horizon strategy which steers the current state deep into the invariant set is proposed. In order to remove offset error, use of disturbance observer is made in the form of state estimator. The efficacy of the proposed method is verified through simulations.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.1
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• pp.1-5
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• 2000

Co-fired resistors for high frequency MCM-C (Multi Chip Module-Cofired) were fabricated and measured their RF properties from DC to 6 GHz. LTCC (Low Temperature Co-fired Ceramics) substrates with 8 layers were used as the substrates. Resisters and electrodes were printed on the 7th layer and connected to the top layer by via holes. Deviation from DC resistance of the resistors was resulted from the resister pastes, resistor size, and via length. From the experimental results, the suitable equivalent circuit model was adopted with resistor, transmission line, capacitor, and inductor. The characteristic impedance $Z_{o}$ of the transmission line from the equivalent circuit can explain the RF behavior of the buried resistor according to the structural variation.