Zero-power control of double parallel magnetic suspension system with mixed polarity

Zero-power control is applied to a double parallel magnetic suspension system with mixed polarity. The most basic magnetic suspension system consists of a suspended object (floator), an electromagnet and a power amplifier. In double parallel magnetic suspension, two floators and electromagnets are controlled with a single power amplifier. The feasibility of the zero-power control in double parallel magnetic suspension with mixed polarity is discussed. It is analytically shown that the condition for the system with a zero-power controller to be controllable is independent of the polarity. It is confirmed experimentally that the zero-power suspension is achieved in both uniform-polarity and mixed-polarity suspension systems.