Project : PMSM Control based on Edge Field measurements by Hall sensors for Vaccum motor

             (2009. 12. 01 ~ 2011. 12. 01)

Recently, PMSMs are utilized for vacuum pumps for their higher power efficiency. In a vacuum pump, a can-type housing

is preferred for vacuum sealing. In these environments, the motor shaft is supported by a single bearing and installation of encoder or resolver is very difficult. In this work, we proposed the low-cost position sensor for PMSM using linear Hall sensors.

These figures show hall sensors, the block diagram of PLL with Adaptive Norch Filer(ANF) and the waveform of hall sensors output. As the diagrams indicate, The output of hall sensors is not clear like sinusoidal wave. FET results indicate that third harmonic components are significant and the position error has to be minimized. Therefore we used ANF and PLL to get a clear sine wave. The ANF canceled out the third harmonics and then the PLL adjusted a frequency and a phase of the filtered hall sensor signals to minimize position error.

The proposed signal process was verified by experiments. Although, the experimental results showed some limits compared with an encoder or a resolver, the proposed position sensor is used for cost effective PMSM driving systems.
 

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