Torque Increase Strategy of Dual Three-phase Permanent Magnet Synchronous Motor Based on VSD Model Harmonic Current Injection

Usually, the dual three-phase permanent magnet synchronous motor (PMSM) has the modeling method of double d-q coordinate transformation and the modeling method of vector space decoupling (VSD). The mathematical model of dual three-phase PMSM based on double d-q coordinate transformation is easy to establish, but there is still coupling between the d-q axis flux linkages of the two sets of three-phase windings. The mathematical model of dual three-phase PMSM based on VSD is relatively difficult to establish, but the mathematical model of dual three-phase PMSM fully realizes decoupling. In this paper, double d-q mathematical model and VSD mathematical model can be converted into each other by the idea of decoupling and coordinate transformation. The vector control method can not only control the harmonic current of a given order, but also improve the output torque by injecting the harmonic current of the given order. When the effective value of the given fifth harmonic current is 1.5A in the simulation, the rated output torque is increased by 0.065N$\cdot$m.