Patent ID: 6871498

Claim:
A method for controlling compressor surge in an electrically assisted turbocharger that is coupled to an internal combustion engine, the turbocharger including an electric motor disposed around a turbocharger shaft to provide rotational movement thereto, the method comprising the steps of: sensing a first parameter indicative of the rotational speed of the internal combustion engine; sensing a second parameter indicative of the rotational speed of the turbocharger shaft; and controlling the electric motor responsive to said first and second parameters so as to avoid surge based on a multi-dimensional map correlating compressor surge conditions to the speed of the internal combustion engine and to the speed of the turbocharger, wherein the step of controlling is performed by an electric motor controller that is coupled to the electric motor and that includes a memory connected thereto having the multi-dimensional map of surge conditions stored therein, and wherein the step of controlling comprises the electric motor controller reversing power to the electric motor in response detected surge conditions.