Tracking – Resonance frequency

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The tracking controller, PIC16F684, is a microcontroller-based extension to our standard driver. The controller adjusts the frequency for maximum current, which gives optimum performance in the motor regardless of temperature and voltage.

When power is applied, the controller turns on the motor and makes an initial frequency sweep to find/store the resonance frequency. The motor is then stopped. The next time the motor is started manually, the stored frequency is used and optimized while the motor is running. When stopped, the last frequency is stored.

We‘ve included some features in our new tracking controller to locate the resonance on the fly while “spinning” the motor up.

The red curve in the above diagram shows the current consumption of the motor.

When the motor is started, the controller will follow the Sw1a-Sw1b arrows until the maximum current is found. Then tracking will start and follow the resonance frequency versus changes in temperature and voltage.

By properly setting the parameters, the Sw1a-b process takes a fraction of a second.