Modeling and control of an ethanol Variable Speed Genset

This paper presents in details a dynamic model suitable for the design of speed controllers of ethanol fueled internal combustion engine (ICE), applied to a Variable Speed Genset. 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 linearization and discretization of the Event Based model. This model has advantages for implementation of a speed controller especially with regard to 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 of implementation. The PI design is developed in frequency domain and its stability is ensured by the phase and gain margin. The Genset also consist of a Permanent Magnet Synchronous Generator (PMSG) and a three phase PWM back-to-back converter that allows grid connection. Modeling and control of the PMSG and the back-to-back converter are also provided. Experimental results are presented to demonstrate the good performance of the system.