Speed control for ethanol engine of variable speed gensets

This paper presents in details a dynamic model suitable for the design of speed controllers of ethanol fueled internal combustion engine (ICE), applied for variable speed gensets. First, two dynamic models are developed for the ICE: the Time Based model and the Event Based model which is referred to the crankshaft angle. The speed controller design is held through the Event Based model linearization and discretization. This model has advantages for implementation of a speed controller especially regarding the transport delay which becomes fixed. For the ICE speed control it is proposed the use of a proportional integral controller because of its simplicity and ease implementation. The PI design is developed in frequency domain and its stability is ensured by the phase and gain margin. In addition, it is also proposed an integral anti-windup action and a feed forward action aiming at faster transient responses. Experimental results on a 50 kW generator set are provided to validade the model and to demonstrate the system good performance.