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Houston -- Control of brushless motors may seem like an issue mainly for power transistor vendors. But Texas Instruments sees it as a DSP application.
The idea is not new. Several years ago, Intel Corp. made a nice market in controlling the motors in air conditioners with 16-bit 80186 MCUs. Essentially, the MCU went into a control loop that measured the speed and rotor position (and hence, the torque) of the motor, took input on the demand, and calculated the timing and amplitude of the current pulses to energize the windings.
In this way, a clever designer could very precisely control the speed and torque of the motor, matching it to the compressor demand, minimizing startup spikes, and so forth. The results were a smaller motor for the equipment manufacturer and less power consumption for the end user.
Since that time, control algorithms have become much more sophisticated. By precisely controlling speed, designers can eliminate belts in variable-speed applications. By very...