Higher-order sliding mode control of a diesel generator set

Diesel engines are used as prime movers and independent power sources in many applications because of their advantages in terms of fuel efficiency, robustness and reliability. This paper presents the results of isochronous speed controller design and experimental analysis of robustness and efficiency of a turbocharged diesel generator set (genset). The steady state performance and transient response of the genset speed utilizing second-order sliding mode techniques with a super twisting sliding mode control algorithm are assessed. The algorithm does not require the time derivative of the sliding variable. It only uses the measured genset speed and does not require the use of an observer. A modification made to the algorithm shows improvement of the genset performance over a wide operating envelope. The influence of this methodology and modification of the algorithm on overall generator performance, in particular in the presence of large load changes and in terms of fuel efficiency, exhaust emissions, starting speed transient response and steady speed variation, are assessed. An algorithm for tuning the higher-order sliding mode (HOSM) controller for the genset is established and presented. The robustness of the controller is investigated and the performance is compared with that obtained by a commercial genset controller and a classical proportional-integral controller.