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Simulating a Halbach cylinder Servo Motor

Motors and generators with MotorSolve

MagNet's magnetization pattern predicting capability is used to design a Halbach cylinder BLDC servo motor in this example. A four pole 12 slot, 3 phase machine is designed here including accurate modeling of an external, impulse magnetization of the Halbach cylinder. Presented below is the magnetizing fixture, the resulting magnetization pattern and performance of the servo motor.

Modeling and simulation of a Halbach cylinder BLDC Servo Motor

METHODS and RESULTS

MAGNETIZING FIXTURE

Detailed or optimal design of a Halbach pattern magnetizing fixture has not been carried out in this example. A simple model, based on typically used fixtures has been used in this example. The model is shown in the accompanying figure. Pre-assembly impulse magnetization is used to create the Halbach cylinders used below.

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MAGNETIZATION PATTERN

The post assembly magnetic field distribution in the servo motor at zero phase current is shown in this figure. The sinusoidal variation of a four pole magnetic field distribution is seen clearly.

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BACK EMF

The back emf of the model is shown here. The saw tooth waveform is due to the Halbach magnetization compared to a rectangular waveform which would be seen in case of a radial magnetized segmented four pole machine for this motor.

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COGGING TORQUE

The cogging torque of the motor is about x % of the rated torque.

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STATIC & MOTION SIMULATION

Some results from the motion and static simulation of the motor are presented next. Steady state torque waveform is presented first.

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FLUX DENSITY in the MOTOR

Instantaneous flux density distribution during operation.

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