Rotor time constant adaptation for induction motor in vector controlled elevator drive

US5476158A · kind A · utility

Assignee

• OTIS ELEVATOR COMPANY · US

Inventors

• Michael Mann · Berlin, DE
• Karl-Heinz Glahe · Berlin, DE

Key dates

• Filing date: Mar 31, 1993
• Grant date: Dec 19, 1995
• Expiry date: Mar 31, 2013

Classification

• Technology area (CPC H): Electricity
• CPC primary: H02P2207/01
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

Torque current reference I.sub.Tref and reference acceleration a.sub.ref are sampled in a vector controlled induction motor drive for developing a quality criterion by which an estimated rotor time constant .tau..sub.2 may be adapted to the actual rotor time constant .tau..sub.2. More specifically, the torque current reference I.sub.Tref and reference acceleration a.sub.ref are sampled and then a slope of I.sub.Tref versus a.sub.ref is plotted against the offset of that line, which offset is proportional to the lead torque T.sub.LOAD. The no-load slope is then determined from this plot and subtracted from an ideal no-load slope and the difference passed through a proportional-integral circuit for providing an estimated rotor time constant .tau..sub.2 which is adapted to the actual rotor time constant .tau..sub.2.