Real-Time Simulation of Permanent Magnet Synchronous Motor Considering Harmonic Currents Based on FPGA

The real-time simulation platform of constant d–q axis inductance parameter permanent magnet synchronous motor model only considers the fundamental wave of magnetic field and it cannot accurately describe the spatial harmonic characteristics of the motor. Thus, this platform is not applicable in the developing and testing of control algorithms suppressing torque ripple and harmonic current. Aiming at this problem, a hardware-in-the-loop platform is built using an analytical motor model called “distributed parameter model” based on magnetic co-energy reconstruction. This model describes the variation of magnetic co-energy, flux linkage, voltage and torque with reference to rotor spatial position. So, it can accurately reflect the nonlinear characteristics including saturation, slotting effects and non-sinusoidal back-EMF. The model is numerically discretized and compiled by Verilog hardware language in FPGA, then tested with closed-loop FOC control algorithm. The real-time simulation can verify the control algorithm with real controller and the simulation step of the motor model is 1 μs. Compared with the bench test results of the actual motor, the spatial harmonic characteristics of the motor in the real-time simulation platform are verified.