| Autor(en): |
Klaus Nenninger, Wolfgang Amrhein, Siegfried Silber und Gernot Trauner |
| Journal: |
6th International Symposium on Magnetic Suspension Technology, 6th ISMST, Turin, Italy |
| Jahr: |
2001 |
| Monat: |
Oktober |
| Zusammenfassung: |
The bearingless single-phase motor with concentrated coils has a nonlinear relationship between current through the coils and resulting levitation force depending on the rotary angle. Thus it is important to know the exact rotary angle for controlling the radial position of the rotor. Normally, four analog hall elements are used to measure and calculate the rotary angle from a sine and a cosine signal. In this paper a rotary angle estimator is presented which only needs one digital hall switch to find the start-up position where the rotary angle is known and the angle calculation can be triggered. During normal operation the rotary angle is calculated by means of torque current and load curve. In case of unexpected load variations the calculation algorithm can be synchronized by the digital input signal of the hall switch. |
