A variable reluctance generator has phase windings and a bias winding. By
controlling the excitation produced by the bias winding, the speed of the
machine or the DC link, a power converter using only diodes can supply
power to a DC bus. A method of operating a variable reluctance machine as
a generator, the machine having at least one phase winding, includes
creating a bias flux linking the or at least one phase winding, and
limiting the phase voltage to a magnitude below that otherwise induced in
the phase winding by the bias flux.