Techniques to Control the Electricity Generation in a Series Hybrid Electrical Vehicle

In a series hybrid electric vehicle (SHEV), an electric generator feeds a dc busbar (containing an electrochemical accumulator), which, in turn, feeds the vehicle traction system. A very important part of the vehicle is its control system that has to maximize the vehicle efficiency, while keeping the emissions within predetermined limits. To attain this goal it can act in two ways: it can switch the electric generator ON or OFF, or when in ON state, it can impose a given power to be delivered. To choose the control actions to perform it needs: an algorithm to understand the behavior of the battery (determine the state-of-charge, maximum power, losses) and an algorithm to make some forecast of the system load (i.e., the power required in the future of the trip, as a function of time). This paper discusses the main problems arising when trying to synthesize the control system of the vehicle, keeping into particular account the second two issues. Some lab tests are also presented, in which some of the proposed controlled techniques are experimentally checked.