A precise open-loop torque control for an interior permanent magnet synchronous motor (IPMSM) considering iron losses

Interior permanent magnet synchronous motors (IPMSM) are preferentially chosen as traction drives for electric vehicles due to their high power and torque density. In a field-oriented control scheme an operation point selection strategy is required to choose appropriate current set points to generate the requested torque with high precision and optimal efficiency. Although the currents are controlled in terms of a closed-loop control, the operation point selection is an open-loop torque control. Thus a precise motor model considering the impact of saturation effects and iron losses is required to estimate appropriate current set points. This paper proposes a lookup-table (LUT) based operation point selection. The lookup-tables are generated offline using the Maximum Efficiency (ME) strategy considering saturation effects and iron losses.