Posted on by admin

Understanding Permanent Magnet Motors

Let us assume we have a 5-phase motor we are trying to analyze. This motor has the following characteristics.

Figure 1 – 5-Phase Motor with 22 Magnets and 25 Slots. OD of 200mm and Stack of 25mm.

Motor Characteristics:
Input Voltage = 48V
Max Phase Current = 40A
Phase Resistance = 0.22 Ohms
Phase Inductance = 1.5mH

The motor’s backEMF is shown below at 100 RPM. It is slightly trapezoidal compared to the Sinusoidal representation.

5-Phase Motor BackEMF at 100 rpm

Problem Statement: Given the above information, can you develop

  1. an approximate torque-speed curve and
  2. A field weakening plot of Torque vs. Phase Angle and
  3. A field weakening plot of Motor Speed Vs. Phase Angle.

What tools and methods will you use to develop an answer?