POWER MANAGEMENT AND CONTROL STRATEGIES FOR A HYBRID VEHICLE WITH A DUAL MODE POWER SPLIT TRANSMISSION

The design of hybrid vehicles inevitably involves two, or sometimes more, power sources. Although successful designs have required a whole range of technological developments, two particular aspects are highlighted here (a) the power splitting or power combining transmission often based on a combination of mechanical and electrical components and (b) the supervisory control strategy for managing the power flows to obtain both high efficiency and good driveability.First, power splitting transmissions (PST) have been reviewed and the performance properties of single and dual mode systems have been analysed and compared. Second, the control system problem has been analysed, focusing on the high level, supervisory controller. Various control approaches are described and comparisons made about the relative merits of competing strategies.It is concluded that a Dynamic Programming approach to this complex multivariable optimization problem offers significant advantages in understanding the problem and in setting a benchmark target for the optimum performance of the hybrid vehicle operation.