Investigation of an Improved Complex Vector Decoupling Control with Synchronous Modulation for the Three-level PMSM Drive

When a motor is operates at high speed, the dynamic coupling term of the magnetic field current and torque current has an apparent impact on the control performance. Simultaneously, the current ripple of the motor is large when the carrier ratio is low. In order to solve these problems, a combination of complex vector decoupling and synchronous modulation is adopted, so that the motor obtains a zero point that cancels the pole of the controlled object in the full speed range which can effectively reduce the impact of coupling terms. In addition, the harmonic content of the current and the changes in torque and speed are reduced. Through an analysis of the closed-loop transfer function and electrical cycle of the motor, a simulation model is established to solve the above problems, and the effectiveness of the proposed method is verified via experiments in a three-level PMSM drive.