Wow, this project sounds super cool! Would love to see results.

A question which was not answered was "what is the difference between BLDC and PMSM". It is kind of a religious discussion, as in essence, all of these motors are Brushless DC (i.e. have no brushes and a DC bus voltage is used to drive them by employing a 3 phase inverter).

The main difference seems to be whether the motor commutation is achieved in a trapezoidal or sinusoidal fashion. In other words, if you use a six step trapezoidal commutatation scheme, then it is a BLDC commutation scheme. On the other hand, if you use any of the many sinusoidal commutation schemes, then it is PMSM. Then, there is the variable on how the motor is wound and what is the resulting BEMF signature. BLDC motors have trapezoidal BEMF and PMSM have sinusoidal BEMF.

At the end of the day, however, you can use any motor with any algorithm. That is you can drive a BLDC motor with BLDC or PMSM algorithms, or a PMSM motor with BLDC or BEMF algorithms. The premise, however, is that you maximize efficiency if you drive each motor with its own pertinent algorithm. Not a big problem for most programmable 3 phase inverters out there which can do either with little effort.

 

If you use 3 phase sinusoidal, then it is not BLDC, it is 3ph AC syncronous, BLDC has only two winding's energized at any one time and is a essentially a DC brushed motor 'inside-out'.
Otherwise both motors are basically the same, physically.
Max.

 

If you use 3 phase sinusoidal, then it is not BLDC, it is 3ph AC syncronous, BLDC has only two winding's energized at any one time and is a essentially a DC brushed motor 'inside-out'.
Otherwise both motors are basically the same, physically.
Max.

Also i think their Magnet to Pole(teeth) ratio are different.
I will make my first E-car using 3Phase Induction electromotor(like tesla model s)(not soon)

 

Also i think their Magnet to Pole(teeth) ratio are different.

I have successfully converted the AC synchronous types to BLDC.
Max.

 

I have successfully converted the AC synchronous types to BLDC.
Max.

Oh Tnx god! How did U do that?!Would u mind Explaining your methods and sharing your experience and results with us?

 

It was a Fanuc AC CNC servo motor that had a proprietary encoder/commutation.
I just replaced this with a standard quadrature encoder that has commutation tracks on it.
Alignment with a scope is required.
Max.

 

Oh Tnx god! How did U do that?!Would u mind Explaining your methods and sharing your experience and results with us?

Switching from BLDC to PMSM is very easy. As I had explained before, you can use either algorithm with either motor topology. They both can use the exact same 3 phase inverter. What you do is to use six step trapezoidal for BLDC, and sine wave commutation for PMSM. In six step trapezoidal, you have six different sectors giving you the six possible currents. Your motor speed will be directly proportional to how fast you commutate through the sectors. On sine wave commutation, however, you would need to implement an algorithm in which the tri phase currents are three sines 120 degrees out of phase. You can use space vector modulation to achieve this. I have a blog posting on eBLDC which details the six currents for six step trapezoidal. Just do a search for "Tackling the Brushless DC Motor Experience" and you should find it.