SVM Direct Torque and Flux Control of Three-Level Simplified Neutral Point Clamped Inverter Fed Interior PM Synchronous Motor Drives

The direct torque and flux control abandons the current control approach but instead regulates the stator flux and torque directly and independently. Consequently, excellent dynamic performance can be expected from the motor drive, making it attractive for low and medium voltage applications. This paper presents a direct torque and flux controlled interior permanent magnet synchronous motor driven from a three level simplified neutral point clamped inverter. This inverter features fewer switching devices and less dc-link capacitor voltage imbalance problems due to the absence of the medium voltage vectors. A novel space vector modulation algorithm is proposed to generate the reference voltage vector for control purposes while balancing the neutral point voltage. The experimental results included verify the effectiveness of the proposed approach.