H bridge motor driver fed by current source SMPS is OK?

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Flyback

Well-Known Member
Hello,
Is it the done thing to supply a 750W fuel pump motor with a 25 Amp current source switch mode power supply?
That is, the fuel pump motor is a Brushless DC motor which is driven by a H bridge, which in turn is supplied by a Current source SMPS...(the output of the SMPS is 25A maximum at 32v).
They say that the current source is partly adjusted by the tacho feedback from the motor....via a Frequency to voltage converter which goes into an error amplifier feeding the SMPS.. so the faster the motor goes, the more current is delivered by the current source SMPS.
What I am wondering is, do the engineers know what they are doing?....I mean, surely all one needs to drive the fuel pump motor is the H bridge driver?...why are they wanting to use the current source SMPS upstream of the H bridge?
Is this a common technique?
 
Sounds odd to me... Surely the motor speed is controlled by the drive frequency to the H bridge, so that's what you'd want to control in your feedback loop - not the drive current.
The only thing I can think of is that the H-bridge is used to determine the direction of current (to generate AC for the windings) and the current-regulator circuit is used to shape the current profile within each half cycle.
Does that sound likely? I know naff all about motor driving mind you...
 
thanks, its the best account i've heard, certainly. Ive searched google and it says nothing, -there is something called a "current source inverter", but that appears to be just a motor with a inductor in series with it.
 
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