Joohn-Sheok Kim

New control scheme for AC-DC-AC converter without DC link electrolytic capacitor

A novel concept for a static three-phase to three-phase power converter for an AC motor drive with unity power factor and reduced harmonics on the utility line is presented. The power circuit consists of two back-to-back connected six-pulse bridges having only a 5-/spl mu/F ceramic capacitor in the DC link. By controlling the active power balance between two bridges, the DC link voltage can be maintained within a 20-V deviation from the nominal value with the small ceramic capacitor regardless of the load variation.<<ETX>>

Torque control strategy for a parallel-hybrid vehicle using fuzzy logic

In this paper, the fuzzy logic based torque controller for a parallel hybrid electric vehicle is proposed. This controller is realized to satisfy the control objectives; improvement on the drive ability of the vehicle, battery charge balance and reduction of NO/sub x/ emission. To construct the proper rule bases of the proposed controller, the dynamo test of the parallel driving system and the investigation on driving condition and vehicle load are carried out. Through the actual road test, it can be proved that the decision-making of this fuzzy logic controller is useful for the improvement of driving performance. The proposed fuzzy logic controller gives superior performance for nonlinear and uncertain system and has robust characteristics to disturbance such as vehicle load and road conditions.

Torque control strategy for a parallel hybrid vehicle using fuzzy logic

In this paper, the fuzzy logic based torque controller for a parallel hybrid electric vehicle is proposed. This controller is realized to satisfy the control objectives; improvement on the drive ability of the vehicle, battery charge balance and reduction of NO/sub x/ emission. To construct the proper rule bases of the proposed controller, the dynamo test of the parallel driving system and the investigation on driving condition and vehicle load are carried out. Through the actual road test, it can be proved that the decision-making of this fuzzy logic controller is useful for the improvement of driving performance. The proposed fuzzy logic controller gives superior performance for nonlinear and uncertain system and has robust characteristics to disturbance such as vehicle load and road conditions.

New approach for the low speed operation of the PMSM drives with rotational position sensors

A new approach to the position sensor elimination of permanent magnet synchronous machine (PMSM) drives for low-speed operation is presented in this paper. Using the position sensing characteristics of the PMSM itself, the actual rotor position, as well as the machine speed, can be obtained even in the transient state. Since the essential back-EMF information is obtained from direct measurement during a special test cycle called MCDI, the operating speed range of the sensorless drives can be extended to 10 RPM. Moreover, the chronic starting problem of PMSM drives can be simply settled by the proposed algorithm. In order to verify the feasibility of the proposed scheme, experimental results in the low-speed range of about 10/spl sim/100 RPM are also presented.

Resonant link bidirectional power converter. II. Application to bidirectional AC motor drive without electrolytic capacitor

This paper proposes a new power converter which consists of two identical 3-phase PWM modulators and a novel resonant circuit. A new control strategy is integrated to realize the bidirectional power converter without an electrolytic link capacitor. The power flow between converters is bidirectional and the regenerative braking is inherent. The source side currents maintain sinusoidal waveforms with a unity power factor. It is observed in the experiment that by balancing the active power between the source and load side, the voltage across a small ceramic link capacitor can be maintained within a small deviation from the reference. Simulation results and experimental results are presented to verify the operational principles. >

Advanced control strategy of parallel hybrid low emission electric vehicle

Recently, the hybrid electric vehicle (HEV) system that consists of a mechanical engine, electrical motor and batteries has gained increasing interest because of the inherent drawbacks of the diesel engine (such as black smoke, nitrogen oxide gas, noise, etc.). In an HEV system, without any external and additional recharging of batteries, an efficient driving characteristic can be easily obtained through a battery conditioning algorithm. In this study, a new driving algorithm for parallel type HEVs is presented. Controlling the battery charge operation, according to the engine speed and acceleration signal from the front driving seat, fuel energy efficiency can be greatly improved and effective emission controllability can be obtained.