Optimal efficiency based Gen-set control for series hybrid work machine

In series hybrid drivelines primary power producer produces majority of the required traction and auxiliary power. Optimizing the efficiency of the primary power producer helps minimizing the fuel consumption of the whole driveline. In this paper primary power producer is a diesel-generator (Gen-set). Diesel is both, torque and speed controlled. Fuel consumption chart, as a function of diesel speed and torque, is used to find optimal efficiency operating point in regard of system load. Supercapacitor is connected to dc-link via actively controlled dc/dc-converter. This supercapacitor module is controlled to provide residual power and it supports gen-set so that the optimal operating point can be used during all phases of the vehicle operation. Control design is tested using simulation model that has been verified with actual hardware components. Results are presented and analyzed, proving that the concept of optimal efficiency control contributes significantly to reduced fuel consumption.