231 – Vector Control Simulation of a Synchronous Reluctance Motor

Model Data

Overview

Since control design and motor design are designed by different designers, cooperative design is difficult. However, in order to meet the sophisticated demands in recent years, it is important to identify problems while coordinating motor design and control/circuit design at the early stages of development. In cooperative design, it is possible to utilize circuit simulation using a highly accurate plant model.
When operating a synchronous reluctance motor (hereinafter referred to as a SynRM), since the nonlinear range of the magnetization properties of an electromagnetic steel plate is used, inductance also exhibits nonlinear behavior. Because of this, a highly accurate plant model cannot be created using only linear methods. In JMAG, it is possible to create a plant model that models actual motors in detail taking into account magnetic saturation characteristics and spatial harmonics exhibited in motors.
In this example, circuit simulation is carried out simulating the control of current and speed by loading a JMAG-RT model for a SynRM into a control/circuit simulator. In addition, comparison with an ideal motor model is performed.

Control Circuit

The control circuit is shown in fig. 1. The rotation speed command value is set to 600 r/min and the d-axis current command value is set to -5 A, and the voltage command value is sent to the motor via the inverter.

Rotation Speed Waveform, d-Axis Current Waveform

Fig. 2 shows the rotation speed waveform for a JMAG-RT model and an ideal motor model, and fig. 3 shows the d-axis current waveform.
It can be seen that both converge to the command value. Moreover, it can be seen that there is a difference in behavior between the two as regards the overshoot.

Coil Current Waveform, Torque Waveform

The coil current waveforms when using the ideal motor model and the JMAG-RT model are shown in fig. 4 and fig. 5, and the torque waveform is shown in fig. 6.
Regarding the rise, the JMAG-RT model has more current flowing, but the torque being generated is lower. This is due to the magnetic saturation of the core being precisely taken into account. In addition, looking at the steady-state torque waveform, it can be seen that there is torque ripple due to spatial harmonics.

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