A control system includes a variable inductor including a magnetic core, a first coil wound around the magnetic core, and a control coil wound around the magnetic core; and a sensor coil wound around the magnetic core, wherein the first coil wound around the magnetic core is coupled between first and second terminals and has a variable inductance across the first and second terminals.

A control system includes a variable inductor including a magnetic core, a first coil wound around the magnetic core, and a control coil wound around the magnetic core; and a sensor coil wound around the magnetic core, wherein the first coil wound around the magnetic core is coupled between first and second terminals and has a variable inductance across the first and second terminals.