Magnetic bearing operation with controller and power amplifiers - involves use of electromagnet current positive and negative directional measurements in position assessment of levitated object

摘要

Two electromagnets (1,1') are energised from separate power amplifiers (3,3') to exert a lifting force on the rotor (4) of a rotating machine positioned between them. The control (5) operates on signals (yip,yin) from current transformers (2,2') in the power lines from the amplifiers (3,3'): to the respective electromagnets (1,1'). The state of movement of the rotor (4) is worked out for the purpose of stabilising its contactless floating position by reaction on the amplifier inputs. This method renders movement sensors, as such, superfluous and eliminates errors by using data obtd. from the bearing itself and not from sensors making measurements at another location. ADVANTAGE - More compact and less costly structure enables air gap data to be used instead of movement measurements by sensors sepd. from bearing.