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My friend and I are doing a sort of academic research about heavy electric vehicles. A sub-project involves choosing the wheel motor and defining the control method.

Aside from what currently exists on the market (this is academic research) we are interested in debating why one solution is preferred above the others (or the pro/cons of each one.)

The main design requirement is the motor power: 50kW to 100kW.

The other important factors for the motor are:

  • Construction complexity
  • Reliability
  • Weight
  • Price

For the control unit:

  • Reliability
  • Weight (e.g. due to big heat sink)
  • Price

Currently, modern technology pushes towards BLDC but we need to explain WHY it is better than other alternatives. We currently considered as a possible alternative an AC motor + inverter (or induction motor?)

My questions are:

  • What are the pro/cons of one compared to the other?
  • In case of AC motor + inverter, could be the inverter be a PWM generator and using the engine coil as low pass filter to optimize everything? yes/no/WHY?
  • Can you please provide reference literature? I investigated myself but most are just one page sheet which just tell the generic stuff about this or that.
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    \$\begingroup\$ I’m voting to close this question because you are asking for a discussion ("debate.") The stackexchange system is set up to provide concrete answers to concrete questions rather than a discussion. \$\endgroup\$ – JRE May 12 at 11:50
  • \$\begingroup\$ This is my first question and if written in bad form I can either edit it or open a new one with specific questions. What is the preferred way? Specific questions can be: * Can the engine coil be used for a (PWM) low pass filter when power is in the order or 50-100kW? * How much temperature should an heat sink for this kind of PWM controller dissipate? \$\endgroup\$ – W'Dragon May 12 at 11:58
  • \$\begingroup\$ PS: I read again my post. About the "debate" in "we are interested in debating why one solution is preferred above the others", I was not asking the community to debate, I pointed out that, since we need to debate internally later on, we need precise answer instead of just "use this" or "don't do that". Sorry for the misunderstading! \$\endgroup\$ – W'Dragon May 12 at 11:59
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    \$\begingroup\$ ROFL Do you want us to write the paper too! \$\endgroup\$ – StainlessSteelRat May 12 at 12:10
  • \$\begingroup\$ circuitdigest.com/article/… Go do some "re-search" and include the diminishing returns of battery mass/energy storage \$\endgroup\$ – Tony Stewart EE75 May 12 at 12:36
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Asynchronous machines (induction motors) are used because of their simplicity and robustness. As soon you add additional circuitry, that advantage diminishes. In difference to a synchronous machine (brushless DC motor),

  • the torque of an asynchronous machine is a function of slip. For a given motor, demanding more torque means having more slip and that means more losses, which have to be supplied through extra reactive power. This is even true for generative braking!
  • losses are mainly on the rotor side, and have to be dissipated by forced convection through the air gap. This creates a requirement for lots of clean air, which is a problem in a vehicle. Pumps for heating systems use the 80°C hot heating water as a convection agent instead. It's worth looking into that idea.

All other differences can be addressed by picking the correct inverter for the machine, but those two differences remain.

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  • \$\begingroup\$ One other advantage of asynch machines is that they are basically copper and iron(maybe held together with aluminium) ... no rare earth materials involved. \$\endgroup\$ – user_1818839 May 12 at 12:56
  • \$\begingroup\$ In a 100kW synchronous machine, you are going to have an excitation winding instead. It's also useful for better control of the machine. \$\endgroup\$ – Janka May 12 at 20:16
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Currently, modern technology pushes towards BLDC

That is not exactly true. Reluctance-permanent magnet hybrids are also and perhaps reluctance-only are also being considered.

What are the pro/cons of one compared to the other?

Advantages in efficiency, reliability, physical size, and performance are under consideration. Each of the advantages can be increased by adding cost or possibly by more clever design.

Can you please provide reference literature? I investigated myself but most are just one page sheet which just tell the generic stuff about this or that.

There are a lot of IEEE publications and a number of texts to consult. The only way to develop a proper comparison is to look for that kind of material.

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