A Neutral-Point Voltage Balance Technique for a Diode-Clamped Three-Level PWM Rectifier Based on Fuzzy Control

The reason why the neutral point (NP) voltage unbalance is analyzed in detail and a Fuzzy Controller based on control index proposed. This way to balance the NP voltage is simple and need not extra hardware cost. Fuzzy controller can automatically and intelligently adapt the value of the control index and change the operation time duration of the small vectors. The Fuzzy controller design has been discussed and the experimental results verify that the proposed technique is correct and the balance of the NP voltage guarantees high power factor of TL-PWM rectifier.