Current Injection-Based VSI Nonlinearity Self-learning Method for Dual Three-Phase PMSM Drives Considering the Effect of Zero-axis Voltage

Self-commissioning has become an important feature of modern electric drives, of which the voltage source inverter (VSI) nonlinearity self-learning is a part. This paper investigates a VSI nonlinearity self-learning method for dual three-phase permanent magnet synchronous motor (DTP-PMSM) drives based on harmonic plane current injection. First, the zero-axis voltage effect of the six-phase inverter is analyzed, which shows that the error caused by the zero-axis voltage can be eliminated by keeping one phase current at zero. Then, a special harmonic plane current injection method is proposed to eliminate the zero-axis voltage effect at arbitrary rotor initial position. In this way, the VSI nonlinearity self-learning considering the zero-axis voltage is achieved. In addition, a novel self-learning process is designed to resist the unbalance factors in the power device and winding, which is easy to implement. Experimental results are in support of the features of the proposed method.