Hi Jeremy,
I believe that the ME0913 is actually a PMAC motor, not a BLDC motor. There is a difference between the motor types (see my recent post about the differences). I agree that a BLDC (trapezoidal wave-form) controller will run a PMAC motor and vice versa, but both types of motors will run better with a correctly matched controller.
I also think that sinusoidal wave-form controllers are more common and reasonably priced than you make them sound. Even the old Sevcon Millipak controller could "operate in Trapezoidal or Sinusoidal wave-form switching modes" (Sevcon, 2008). Since the newer Gen4 controllers are designed for both PMAC or ACIM motors, I believe that they only operate in sinusoidal mode, though there may be a configuration setting to force one into a trapezoidal wave-form. I know that the Gen4 does allow for field weakening to extend the speed range of a PMAC motor beyond the BLCD limitation of max RPM when the motor back-EMF reaches the drive bus voltage. Another way to look at it is that BLDC controllers are based on a speed control loop and PMAC controllers are based on a torque control loop.
On the other hand, Kelly's brushless controllers appear to be exclusively BLDC (trapezoidal wave-form) controllers.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "Jeremy" <jeremy_harris_uk@...> wrote:
>
> The ME0193 is a permanent magnet brushless DC motor (often just abbreviated to BLDC). It uses a trapezoidal three phase drive from a controller that generates this waveform from the DC battery supply. Because the motor provides absolute rotor position feedback (using Hall sensors) to the controller, you need a separate controller for each motor, as the chances of getting a couple of motors to remain mechanically synced to the accuracy required to allow them to run from a single controller is pretty slim.
>
> The controllers are pretty simple things, just some electronics that generates the three phase switched waveform from the sensor position feedback signals and a pulse width modulated part that in essence is the same principle as that used on a brushed motor for power control, except it pulse width modulates all three phase outputs.
>
> I've designed and built fairly high power BLDC controllers and they can be pretty simple if lots of fancy features aren't required. They can also get to be pretty complex if all these fancy features, like user-programmability etc, are required!
>
> I've seen it mentioned that these motors need sinusoidal drive. This isn't the case, although they will run more quietly and very slightly (only maybe 1%) more efficiently with a sinusoidal three phase drive. However, sinusoidal drive controllers are both pretty rare and rather expensive, so most folks stick with straight trapezoidal switched controllers, like those from Sevcon, Kelly etc.
>
> Jeremy
>
>
>
> --- In electricboats@yahoogroups.com, Michael Mccomb <mccomb.michael@> wrote:
> >
> do you know, does a motor such as a ME0913 require an individual controller due to some sort of frequency feedback that the motor must supply?
> >
>
No comments:
Post a Comment