PROJECT TITLE :

A New Bumpless Rotor-Flux Position Estimation Scheme for Vector-Controlled Washing Machine

ABSTRACT:

For a washing machine, permanent-magnet (PM) motors are commonly used due to their superior efficiency, high torque-to-volume ratio, and thus on. PM motor driving system with vector management theme needs rotor-flux position data. Hall-effect position sensors are often used for that purpose because their volume is little and is price effective compared with other types of position sensor such as an encoder, although they have low resolution of position information. Usually, two low-resolution hall-effect sensors are used to produce rotor flux position for price reduction purpose and it means that four resolutions per one electrical 360° rotation. The detected rotor-flux position by hall sensor signals is manipulated to vary linearly by interpolation methodology. However, because of electrical and mechanical nonuniformity related to hall sensors, the calculated or estimated position is not linearly changed. In other words, there exist bumps at the point where hall signal happens even at the constant speed operation and it degrades management performance. To unravel this downside, this paper proposes a completely unique scheme for bumpless position estimation. Additionally, the proposed reduced-order observer will not use mechanical parameters such as inertia. The validity and effectiveness of the proposed algorithm are verified by experiments on a prime-load laundry machine vector-controlled with two Hall-effect sensors.