Engine torque ripple cancellation with an integrated starter alternator in a hybrid electric vehicle: implementation and control

Integrated starter alternators (SA) allow greater electrical generation capacity and fuel economy and emissions benefits of hybrid electric automotive propulsion. The drive usually comprises a field-oriented induction motor or vector-controlled permanent magnet motor coupled to the crankshaft of the engine directly or by a belt. These drives have high bandwidth torque control and may be used for active cancellation of the significant ripple torque inherent to internal combustion engines. This paper presents an analytical model useful for the analysis of the combustion engine torque and describes a control system that uses observer-based high fidelity torque feedforward and engine speed feedback to generate a disturbance input decoupling torque command for the SA to cancel the engine torque ripple.