Turbocharger control

Abstract

A turbocharger system comprises: a turbocharger having a rotatable shaft arranged to be driven by exhaust gases from an associated engine and coupled to a turbocharger electrical machine; and a controller configured to switch the turbocharger electrical machine between a first mode in which electrical energy is drawn from the turbocharger electrical machine acting as a generator and a second mode in which energy is provided to the turbocharger electrical machine to act as a motor. The controller may be configured to switch between the first mode and the second mode based upon the power factor for the electrical energy generated by or supplied to at least one of: the turbocharger electrical machine; and an engine electrical machine coupled to the associated engine.

Dependencies are inferred from the claim text.