Direct Torque Control Method of Induction Machines Using Three-level Space Vector Modulation

摘要

To improve the traditional direct torque control, bring in the stator field-oriented method, and introduce how to realize the quick response under the constant stator flux amplitude. Then directly calculate the accurate voltage vector values according to the angle that the flux goes across during a cycle and the difference between the flux's actual and desired values. In the last the space vector PWM strategy is used to modulate the voltages. Also a simple neutral-point voltage balancing control method is proposed to restrict the neutral voltage offset. Through the simulation debugging, find that new method causes smaller harmonic currents, faster torque response and constant switching period. Besides the neutral-point imbalance is restrained in a small bound. The emulation results verify the correctness and feasibility of the proposed control scheme.