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# SRM Design Optimization

Motors & Generators with MagNet

The design of Switched Reluctance Motors (SRM) is a complex optimization problem involving a large number of geometrical and electrical parameters. In practice, this can be a challenging task involving a large number of iterations and a long design cycle.

The example presented here demonstrates how OptiNet searches for the improved design of a 8/6 SRM to maximize the torque generated while conforming to manufacturing and operating constraints.

## VARIABLES

The geometry of the motor is defined based on the parameters shown in this figure:

• Pole angles (ßr , ßs)
• Pole heights (Hr , Hs)
• Back iron depth

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## SETTING the VARIABLES in OptiNet

The initial, minimum and maximum values of each variable are entered. The user has the ability to vary the parameters as continuous or discreet variables.

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## OBJECTIVE FUNCTION - MAXIMIZING the AVERAGE TORQUE

The objective is to maximize the average torque on the rotor while running at a peak current of 14.5 amps.

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## CONSTRAINTS - AVERAGE TORQUE

In this example, there is a constraint that the average torque on the rotor must be greater than 27.0 Nm.

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## MAXIMUM TORQUE ON ROTOR vs SOLUTION INDEX

After 13 hours, OptiNet has evaluated the design objectives and constraints against over one hundred thirty different SRM designs (as defined by the tolerances on each variable), represented here by each point on the solution index.

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Initial
Final
βr 16 degrees 18.92 degrees
βs 11.5 degrees 11.93 degrees
Hr 18.0 mm 18.92 mm
Hs 25.0 mm 26.16 mm
Avg. Torque 33.19 Nm 35.16 Nm