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This thesis proposes a decoupled self-tuning proportional-integral controller applied to scooter idle stop system to deal with the parametric variation and external disturbances in the driving mode. At the same time, a novel method of directly adjusting voltage is proposed to solve the problem of excessive power potentially generated in the generation mode in order that the generated power can be charged to the scooter battery safely.
The dynamic mathematical model of permanent magnet synchronous motor (PMSM) in Integrated Starter Generator (ISG) is built using a simple space vector method. Then the PMSM equations are transferred into the steady state equations for the reference of the decoupling self-tuning proportional-integral controller design. The results of this study shows that the ISG has a fast and smooth transient current response in the driving mode and reaches the steady state at 0.15 second. Moreover, this controller has a good robustness under parametric variation and external disturbances condition. Experimental results in a 150 cm3 scooter demonatrated the same performances using the proposed controller.
In the generation mode of ISG, the virtual Hall signals are employed to trigger the gate switches of the Metal Oxide Semiconductor Field Effect Transistor module and thus to shift the phase voltages. As a result, the generated high ac power can be transferred into the low dc voltage to charge the scooter battery safely. The results of experiments shows that the phase voltages can be shifted real-time by the virtual Hall signals and the feasibility of phase voltage modulation under full speed range has been verified.
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