Fault-tolerant control of heteropolar magnetic bearings (Vibration control)

Flux coupling in heteropolar magnetic bearings permits remaining active coils to assume actions of failed coils to produce force resultants identical to the un-failed actuator. A distribution matrix of voltages which consists of a redefined biasing voltage vector and two control voltage vectors can be optimized in a manner that reduces the peak flux density. An elegant optimization method for calculating distribution matrices by using Lagrange Multiplier is presented. The distribution matrices can also be optimized for a magnetic bearing with large path reluctances by using weighted flux density Euclidean norm. Position stiffnesses and voltage stiffnesses are calculated for the fault-tolerant magnetic bearings. Simulations show that fault-tolerant control of the multiple poles failed magnetic bearings with a flexible rotor can be achieved with reduced load capacity. Fault tolerant control of a magnetic bearing with grouped currents is developed. Hardware requirements for the fault tolerant control can be considerably reduced by using this control scheme with grouped currents.