3 level GTO converter-inverter pair system for large capacity induction motor drive

A 3 level converter-inverter pair system for large capacity induction motor drives is proposed. A new PWM method for the 3 level converter and inverter based on the space voltage vector is proposed. The experimental results clarify that the PWM method can minimize the harmonic components of the output voltage and current under the minimum pulse width limitation of the GTO's and suppress the fluctuation of the neutral point DC voltage. Loss factor sigma is calculated to analyze current distortion of the synchronous PWM method for 3 level converter. The characteristics of the converter-inverter pair system are confirmed by IGBT test equipment. A high performance 4000 kVA GTO converter-inverter pair system is made to drive an induction motor.<
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