Allan Roy Gale

Starter-alternator for hybrid electric vehicle: comparison of induction and variable reluctance machines and drives

This paper presents the experimental results of using induction and variable reluctance machines as the starter-alternator in a hybrid electric vehicle. The frame sizes of these machines are dictated by transient engine cranking loads. Therefore, in their design, the machines are assumed to be in deep magnetic saturation and the resultant thermally constrained electric loadings are predicted from the calculated electromagnetic air gap surface traction. This design approach results in machine performance predictions in close agreement with prototype measured results for the induction machine. Similar conditions hold for the variable reluctance machine. Experimental results show that both machines require substantial inverter kVA rating to meet magnetizing and overdrive requirements. The series configured induction motor developed 300 Nm of torque at 250 RPM with 115 A/sub RMS/ phase current from the inverter drive whereas in its parallel connection it required nearly 240 A/sub RMS/. The same held for the variable reluctance machine.

Electric drive subsystem for a low-storage requirement hybrid electric vehicle

Integrating an electric machine drive system into the powertrain of a hybrid electric vehicle (HEV) represents a challenging exercise in packaging complex electromechanical and power electronic subsystems. The Ford combined alternator starter (FCAS) and its attendant power and control electronics are physically partitioned because power electronics has not yet evolved to the stage in which fully packaged drives can be realized. A similar situation exists for the control and sensor subsystems necessary for a fully functional high-performance drive. Hardware partitioning requires that more attention be given to installation issues and to mitigating system interactions. The FCAS system consists of an integrated starter/alternator (S/A), an S/A module (SAM), and a vehicle electrical infrastructure that can support the power and energy levels demanded. Our field experience with the FCAS system is presented along with test results obtained from vehicle operation.

Nonlinear model and momentary performance capability of a cage rotor induction machine used as an automotive combined starter-alternator

This paper presents the calculated and the measured performance capability of a cage rotor induction machine used as a direct connected, crankshaft speed, combined starter-alternator for an automotive diesel engine in an experimental hybrid electric vehicle. The calculated results are based on a nonlinear equivalent circuit model of the machine which considers saturation in the stator and rotor magnetizing flux paths. The development details of this model are given as well as several sets of calculation results for the induction machine previously described. Finally, measured maximum performance results for the test machine are presented and compared with model based calculated results for the same operating conditions of speed, terminal voltage and current.

High efficiency operation of a hybrid electric vehicle starter/generator over road profiles

Efficient operation of induction motor starter/generator systems is an important part of the power management function that is required in the self contained vehicular environment. This paper characterizes the performance of a fuzzy logic controller for a hybrid electric vehicle starter/generator that is used to maintain optimum efficiency operation under both steady state and dynamic loading conditions. In steady state, automatic mapping of the maximum efficiency operating points is achieved. In-vehicle dynamic loading is emulated in the laboratory using a motor development platform that can replay industry standard FTP75 road profiles and apply them to the starter/generator. The effects of velocity transients and the bandwidth of the fuzzy controller on efficiency are presented. The effectiveness of the fuzzy controller in maintaining high efficiency operation and in reduced heating is demonstrated.

HEV S/G [hybrid electric vehicle starter/generator]

This article demonstrates the effectiveness of a fuzzy-logic controller to automatically operate an HEV S/G (hybrid electric vehicle starter/generator) at its maximum efficiency under static conditions and over industry-standard road-profile dynamic loads. The effects of transient behavior and controller bandwidth are investigated. Experimental results also show that reduced heating can be achieved.