A
magnetic bearing system (120) includes a first active
magnetic bearing (AMB) (202) including a first group of electromagnetic actuators (306, 310, 314, 318) to support a shaft and a second AMB (204) including a second group of electromagnetic actuators (308, 312, 316, 320) to support the shaft. A controller for the two AMB's includes a multi-phase topology (400) with a plurality of active current switches for controlling the electromagnetic actuators (306-320) of each of the first AMB (202) and the second AMB (204). Each
electromagnetic actuator (306, 310, 314, 318) of the first AMB (202) is electrically coupled to an
electromagnetic actuator (308, 312, 316, 320) of the second AMB (204). Each pair of coupled electromagnetic actuators (306, 316) is respectively connected to
three phase legs (418, 420, 422) of the topology (400) of the controller, whereby one end (X2+, X3−) of each of the electromagnetic actuators of a pair (306, 316) is connected to one phase leg (420) of the topology (400) and the other ends (X1+, X4−) are respectively connected to two further phase legs (418, 422) of the topology (400). The controller is operable to receive information indicative of a position of the rotor shaft and supply an adjustment
signal to the
magnetic bearing system (120) to adjust the position of the shaft.