• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.250-252
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• 2000

A simple analysis method for inverter-fed induction motor using F.E.M and equivalent circuit is proposed. And an optimum shape of rotor slot for 2Hp inverter-fed induction motor is determined by combining the proposed analysis method and an optimization algorithm. Conjugate gradient method is used for the optimization algorithm. The optimization is performed for higher efficiency and reduction of harmonic loss in the inverter-fed induction motor. The optimization results are verified by comparing with those of the time-step F.E.A and the experiment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.4
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• pp.124-134
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• 2011

A new dead time compensation scheme that can exactly estimate the dead time and inverter nonlinearity under parameter variations is proposed for a PWM inverter-fed PMSM drive. The proposed scheme uses the fact that the sixth harmonic component in total disturbance estimated under the presence of various uncertainties is mainly caused by the dead time and inverter nonlinearity. The total disturbance due to the parameter variations as well as the dead time and inverter nonlinearity is estimated by the adaptive scheme. The sixth harmonic component is extracted from this total disturbance through harmonic analysis. The obtained sixth harmonic is processed by the PI controller to estimate the disturbance caused by the dead time and inverter nonlinearity in the stationary reference frame. The effectiveness of the proposed scheme is verified. Without requiring an additional hardware, the proposed scheme can effectively compensate the dead time and inverter nonlinearity even under the parameter variations.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.11
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• pp.568-574
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• 2001

This paper describes a current fed high frequency resonant inverter can be used as the power supply for wax-sealing. This circuit configuration is composed of conventional two unit inverter of single ended current find type in parallel. The proposed inverter can realize ZVS operation by using resonant capacitor to ZVS capacitor and has merits not only reduction of switch current distribution but also extension of load range in comparison with the conventional single-ended current fed high frequency resonant inverter. This analysis of proposed circuit uses normalized parameter and characteristic estimation which is needed in each step before design is generally described according to normalized frequency($\mu$), normalized resistance(λ) and parameters. On the basis of characteristic values, a method of the circuit design is presented. Also, the theoretical analysis is proved through experiment and this proposed circuit shows that it can be practically used as the power supply system for wax-sealing and DC-DC converter.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2695-2697
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• 1999

A new three-phase voltage-fed inverter using partial resonant converter with high power factor and high efficiency is proposed. The proposed Flyback converter is constructed by using a resonant network in parallel with the switch of the conventional converter. The devices are switched zero voltage or zero current eliminating the switching loss. This paper introduces elimination of harmonics compared with conventional SPWM inverter and three-phase voltage-fed inverter using Flyback converter.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.547-553
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• 1998

In this paper, we composed of utility interactive pv generation system of voltage source inverter, and represented uninterrutible power supply (UPS) equipment maintaining constant voltage, using a pulse width modulation(PWM) voltage fed inverter, as power source disconnection, voltage variation and output current variation with load variation. This system is driven by being synchronized voltage fed inverter and AC source, and in the steady state of power source charge battery connected to dc side with solar cell using a photovoltaic (PV) that it was so called constant voltage charge. In addition, better output waveform was generated because of PWM method, and it was proved to test by experiment maintained constant output voltage regardless of AC source disconnection, load variation, and voltage variation of AC power source.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.283-287
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• 2013

This paper presents a method for calculating iron losses in three-phase induction motors under the inverter supply through the field-circuit coupled time-stepping finite element method (FEM). Iron losses are calculated by using the three-term iron losses separated model and modifying the loss coefficients obtained by the iron losses curves which are provided by the manufacturer under the sinusoidal supply. Simulation results by the presented method are verified by the measured results with an error lower than 5%, confirming the validity of the proposed method. Finally, iron losses distribution of the inverter-fed three-phase induction prototype motor is shown.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.100-105
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• 2003

This paper proposes a new auxiliary resonant DC link(ARDCL)snubber circuit and deals with its power loss on the basis of actually-measured conduction loss characteristic of switching device module. Voltage-fed soft switching three-phase inverter using proposed ARDCL snubber circuit is presented along with its performance evaluations. And, the power loss analysis of three-phase hard and soft switching inverter are carried out from the point of simulation and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.5
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• pp.401-408
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• 2012

A simple on-line elimination strategy of the dead time and inverter nonlinearity using the current slope information is presented for a PWM inverter-fed IPMSM (Interior Permanent Magnet Synchronous Motor) drive. In a PWM inverter-fed IPMSM drive, a dead time is inserted to prevent a breakdown of switching device. This distorts the inverter output voltage, resulting in a current distortion and torque ripple. In addition to the dead time, inverter nonlinearity exists in switching devices of the PWM inverter, which is generally dependent on operating conditions such as the temperature, DC link voltage, and current. The proposed scheme is based on the fact that the d-axis current ripple is mainly caused by the dead time and inverter nonlinearity. To eliminate such an influence, the current slope information is determined. The obtained current slope information is processed by the PI controller to estimate the disturbance caused by the dead time and inverter nonlinearity. The overall system is implemented using DSP TMS320F28335 and the validity of the proposed algorithm is verified through the simulation and experiments. Without requiring any additional hardware, the proposed scheme can effectively eliminate the dead time and inverter nonlinearity even in the presence of the parameter uncertainty.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.238-242
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• 2004

The paper describes an automatic frequency control current-fed inverter for forging applications. The IGBT in series with diodes as its switching devices in the inverter circuit which is of full-bridge type. The operating frequency is automatically tracked to maintain a small constant leading phase angle when load parameters change. The load voltage is controlled to protect the switches. The output power can be adjusted by varying the input current from phase controlled rectifiers which is a part of current source. The system has been operated at 15-17 kHz. The output power transferred to the load is 1,595 watts. It can heat the steel work pieces with 15 mm diameter and 120 mm long from room temperature to approximately 1100 $^{\circ}C$ within 20 seconds with 0.97 leading power factor on the input side.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.215-225
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• 1994

In this paper, a performance evaluation of different current regulators for induction motor drive systems fed by IGBT inverter is presented. The twoparts of current regulation are considered : current error compensation part, voltage modulation part. The characteristics of hysteresis, synchronous PI, decoupled PI, predictive, deadbeat and stage feedback controllers are analyzed and the steady-state performances and transient responses of current regulation are well compared through the simulation and experimental results.