A new PWM speed control system for high-performance AC motor drives

An approach to speed control for AC motor drives that uses programmed PWM (pulse width modulation) switching patterns over the complete range of output speed is presented. The scheme provides smooth operation during the required switching-pattern changes and guarantees high-quality output voltage and current in the AC motor load, making it most suitable for high-performance, high-efficiency applications. A detailed description of the scheme and its realization is provided. Results of an experimental investigation on a variable-speed induction motor and a permanent-magnet synchronous motor drive system illustrate the advantages of the scheme.<
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