• Proceedings of the KIPE Conference
• /
• 2001.07a
• /
• pp.459-463
• /
• 2001

Since recent inverters are formed IGBT VVVF inverter its switching speed has been increased relative to the conventional inverters and the motor design based on the switching surge voltage at the inverter output is very important factor. Therefore, motor and inverter should be designed to have the optimal characteristics by considering the mutually limited conditions. On this research the design technology characteristics for inverter driving traction moor is compared to the products in Korea and the analysis is performed. Thus, it is intend to re-estimate the technology level and introduce the products by HHI, which is driving on Seoul subway line 6 since December, 2000.

• Journal of Power Electronics
• /
• v.9 no.2
• /
• pp.224-231
• /
• 2009

The induction motor rotor fault diagnosis system using current signals, which are measured using an axis-transformation method, is presented in this paper. In inverter-fed motor drives, unlike line-driven motor drives, the stator currents are rich in harmonics; therefore fault diagnosis using stator current is not trivial. The current signals for rotor fault diagnosis need precise and high resolution information, which means the diagnosis system demands additional hardware such as a low pass filter, high resolution ADC, and encoder, etc. The proposed axis-transformation method with encoder and without encoder is expected to contribute to a low cost fault diagnosis system in inverter-fed motor drives without the need for any additional hardware. In order to confirm the validity of the developed algorithms, various experiments for rotor faults are tested and the line current spectrum of each faulty situation using Park transformation is compared with the results obtained from fast Fourier transforms.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.529-534
• /
• 1998

In this paper, control strategies of the bridge-type ZVT inverter for AC motor drive application were discussed. The topology of the ZVT inverter is analyzed with a description of the control conditions based on the load current. And a new resonant control algorithm by using load current feedback and modified SVM algorithm for the proposed ZVT inverter is proposed in order to achieve the ZVT switching condition in full control range. The detailed computer simulation and experimental results represent that ZVT and ZCT operation for the main and auxiliary switch, respectively, was achieved.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.2056-2057
• /
• 2007

Recently we installed inverter system in $ind{\acute{u}}ction-m{\acute{o}}tor$ for the energy saving. But inverter system generates harmonics, and it causes a lot of issues. malfunction of meter, damage of instrument, overheating of motor. In this study, you can see how to deal with harmonics of inverter system by diagnosis of the power quality.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.11
• /
• pp.1584-1590
• /
• 2017

This paper presents a implementation method of reliable speed limitation controller considering motor parameter variation in high speed operation. In spinning process of drum washing machine, speed increase has to be limited when unallowable imbalance mass is detected. Otherwise, severe noise and vibration can happen because noise and vibration are proportional to imbalance mass. To detect imbalance mass, d-axis current magnitude is used. However, we have to compensate for back-emf and power supply variation by means of detecting them because d-axis current is affected by both of them. On the other hand, we have to carefully estimate back-emf because back-emf is affected by stator resistance variation and inverter voltage error. Stator resistance variation can happen by manufacturing process for mass production or temperature variation in running. And there are inverter voltage errors between command voltage from micro-computer to inverter and real voltage from inverter to motor because of rising and falling time delay and turn-on resistance of power semiconductor switch. To solve this problem, we propose 2-step align current injection method which is to inject step-wise current right before starting. By this method, we can simply obtain stator resistance by ratio of voltage without inverter voltage error and current, and we can measure inverter voltage error. So we can obtain more exact model current, and then by simple calculation with compensation gain, we can estimate more accurate motor back-emf. We show that this method works well. It is verified through experiments.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.19 no.5
• /
• pp.391-398
• /
• 2014

This paper presents a resonant step-down DC/DC converter to reduce the voltage stresses of a 3-phase inverter module under the three-phase AC utility line condition. Under this condition, a conventional 3-phase inverter module suffers from high voltage stresses as a result of the high rectified DC link voltage; hence, a high-cost high-voltage-rating inverter module must be used. However, using the proposed converter, a low-cost low-voltage-rating inverter module may be adopted to drive the motor even under the 3-phase AC line condition. The proposed converter, which can be realized with small size inductor and low-voltage-rating semiconductor devices, operates at a high-efficiency mode because of the zero-current switching operations of all the semiconductor devices. The operational principles are explained and a design example is provided in the study. Experimental results demonstrate the validity of the proposed converter.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.5
• /
• pp.1821-1834
• /
• 2017

Medium voltage control applications due to obtain better output voltage and reduced electro-magnetic interference multi level inverter is used. In closed loop control with inverter, the PI controller does not operate satisfactorily when the operating point changes. This paper presents the performance of Co-Efficient diagram PI controller based indirect vector controlled induction motor drive fed from three-level inverter under different operating conditions (dynamic and steady state). The proposed Co-Efficient diagram PI controller based three level inverter significantly reduces the torque ripple compared to that of conventional PI controller. The performance of the indirect vector controlled induction motor drive has been simulated at different operating conditions. For three-level inverter control, a simplified space vector modulation technique is implemented, which reduces the coordinate transformations complications in the algorithms. The performance parameters, torque ripple contents and THD of induction motor drive with three-level inverter is compared under different operating conditions using CDM-PI and conventional PI controllers.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.339-346
• /
• 2005

It is complex to realize the reference voltage vector by the space vector PWM method in three-leg two-phase inverter In this paper a new PWM technique for three-leg two-phase inverter fed two-phase induction motor is poroposed assuming that three-leg two-phase inverter is equivalent circuit for 'four-leg two-phase inverter with the connected two windings'. From assumption, six sectors are decreased to four sectors, and simple sinusoidal PWM method instead of SVPWM is applied to three-leg two-phase inverter. Also, the switching pattern to determine the switching periods at each sector is proposed. Practical verification of theoretical predictions is presented to confirm the capabilities of the new techniques.

• Proceedings of the KIEE Conference
• /
• 1988.11a
• /
• pp.337-340
• /
• 1988

This paper describes a fast response control of an inverter-fed induction Motor. The transfer function of the induction Motor controlled by this control method ie very similar to that of a separately exited dc motor. This paper presents the linear control method for the transfer function in the control of an inverter-fed induction motor, Acceding to this control, the response speed is correctly grasped faking the leakage inductances into account and the inverter-fed induction motor is controlled with fast response.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.38 no.7
• /
• pp.481-491
• /
• 1989

A compensation strategy for the phase-difference control method, which has been reported as a new driving method of a 2-phase inverter-fed induction motor, is proposed. The phase-difference control method extends the control range of the speed and eliminates the harmonic contents of the output voltage of the 2-phase inverter-fed induction motor. However, the phase-difference angle becomes narrower, motor efficiency deceases more and pulsating torque increases more. As the counterplan for these shortcomings of the phase-difference control method, a hybrid control method which combines the phase-difference control with the voltage control is proposed. The algorithm to realize a hybrid method is presented. As an example, a model composed of 5 regions has been analyzed by computer simulation in terms of motor performance and the results have been compared with experimental results.