| Summary: | 碩士 === 中華科技大學 === 機電光工程研究所碩士班 === 101 === Abstract
The traditional six-switch three-phase (6S3Ph) inverter is used to variable speed drive for AC motors and uninterruptible power systems over the years. However, The current control method in power electronic circuits play an important role, especially the PWM(Pulse Width Modulation) converter is widely used in AC motor drives and continuous AC power supply. The conventional methods including triangular wave or space-vector-based chopper control or hysteresis control, rather the former is a fixed switching frequency, the latter is a variables witching frequency. This thesis presents an adjustable hysteresis current control. The scheme is consisting of two single-phase switching voltage source to supply the three-phase induction machine drive. The technology is based on single-phase four-switch inverter hysteresis current controlled that can reduce the switching frequency and obtain lower harmonic performance to improved third-level phase variable voltage source with hysteresis of inverter. In this research, the output load torque and THD are used to adjust value of current waveform and hysteresis, respectively. The method could reduce the switching frequency and lose under the limit maximum THD value.ThePSimsofeware simulation and verified that the method is simple and effective.
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