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Nissan first Japanese Co. to offer EV with RE.

26K views 130 replies 17 participants last post by  Deanwvu 
Conceptually the Volt type serial ICE/electric motor hybrid is much simpler than the parallel hybrid. I think Toyota tried several different ideas before reaching the Prius type drivetrain, which is much more complex mechanically than the serial design. Why? It is possibly because of the very nature of electric motor; i.e. the motor is generating electricity (back or counter electromotive force) while it is rotating. The voltage of this force increases in direct relationship to the rotational speed and the strength of field magnetism, and if the voltage becomes equal to the incoming (driving) voltage the motor loses torque (no incoming current). In order to reduce this current impeding force you have to either increase the supply voltage or weaken the field magnetism. For a small EV intended for slow max speed (golf cart) you do not have to worry about this phenomenon. But for freeway speed this can be a challenge. You might need a transmission mechanism so that you can keep motor speed low and torque high. Toyota, I speculate, abandoned the idea of using the motor all the way to the freeway speed, and utilized the high torque nature of electric motor at low rpm as the source of start up power and slow-speed runabout as well as a power booster (green turbo) to supplement a smallish ICE. By looking at the Prius motor you know it is very well designed for high efficiency and high torque. Basically it is a permanent magnet synchronous motor with additional reluctance torque poles intended to be driven by a variable voltage (PWM) and variable frequency inverter, a Toshiba original.
 
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