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Hybrid electric vehicles -- Evaluation, Nonlinear control theory, MATLAB


Electric vehicle manufacturers are looking for ways to optimize energy use for vehicle range extension and reduction of battery capacity. Electric motors have lower efficiencies at very low speed and high torque. This is typically at vehicle launch from standstill, at very low speeds, and during energy regeneration at lower speeds and approaching standstill. The KersTech solution is a breakthrough technology allowing supplement of the electric drive with a hydraulic drive, active in lower speeds ranges, dropping out as the electric motor takes over in its higher efficiency range of operation. The report consists of four parts. Part I presents novel the hybrid vehicle simulations in MATLAB. Both the Diesel-Hydraulic Hybrid Vehicle and Electric-Hydraulic Hybrid Vehicle have been simulated and compared in this report. Part II deals with the electrical system control design. Permanent magnet synchronous motors have been widely used in hybrid electric vehicle applications. Permanent magnet synchronous motors have a small size, high efficiency and high performance. This report presents a mathematical model of permanent magnet synchronous motor. Power switching electronics are used to generate the desired voltage/current from DC source. A pulse width modulation technique controls the switching power electronic by creating a control signals which are applied to their gates. The whole circuit of the inverter based on space vector pulse width modulation is simulated in MATLAB/Simulink and its results are presented. Field-oriented control is implemented via digital signal processors to control the permanent magnet synchronous motor. Clarke and Park transformations are applied to “abc" coordinate frame of the permanent magnet synchronous motor model to get the “qd" coordinate frame used in the field oriented control technique. Hence, the developed torque and the magnetizing the flux component are controlled separately. PI controller is used to control the motor speed and torque. PI controllers are designed using frequency response method and a symmetric optimum method. The whole system is simulated based on the mathematical model of PMSM and field oriented control method with designed PI controllers. Simulation results show the PMSM to have perfect dynamic response. A digital signal processor can be used to implement the field oriented control algorithms and compute the parameters in real time. Implementation of field oriented control of a permanent magnet synchronous motor shows that the motor has satisfactory response in terms of torque ripple and speed response. Nonlinear control, including Sliding Mode Controller and State Dependent Linear Matrix Inequality Controller, are also proposed as a powerful control technique to govern the speed of the permanent magnet synchronous motor in hybrid vehicle applications. In Part III, we discuss the hydraulic system design. Finally, in Part IV, the dSPACE hardware controller is used for the overall control system design.


This is a final report, NITC-RR-555, from the NITC program of TREC at Portland State University, and can be found online at:



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