Analysis of static and dynamic FG errors for motor speed control (driven by a single Hall element sensor)

A driving system is described which uses a sensor in common for detecting commutation signal, motor speed signal, and rotor position signal, all to the motor coil, and which can operate as a brushless DC motor equipped only with one piece of a Hall element sensor. In this driving system, because the static jitter is 10 times or more of that of the conventional integral pattern motor speed signal (FG) detecting system, sufficient rotational precision can not be achieved by general speed feedback control. To solve this problem, it is shown that high rotational precision can be maintained by introducing a digital multinotch filter that can correct the static FG jitter. The quantization error is related to the dynamic jitter, and the effect of these two errors on the speed control performance is simulated.<
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