I plan to use a BLDC motor of around 1/3 hp supplied by a DC rail that is generated from AC mains. If the AC voltage is from 100 to 250Vac, I would have a rectified DC supply of from 141Vdc to 352Vdc.
The speed of the motor will be controlled by a purpose-built 3 phase electronic speed controller. In order to be able to use a single model of DC motor at any mains voltage I intend to use PWM to control the motor DC voltage to be about 140 VDC. ie the purpose of the variable voltage control is to keep the DC rail at about 140 VDC when the AC mains voltage varies between about 100 to 250 VAC.
For example, when VDC=141V I will apply 100% duty PWM
and when VDC=353V I will apply 40% PWM.
Is this voltage control system adequate?
Can a single motor model be used this way.
I have a single DC bulk voltage generated from mains, this is the dc voltage that would be commuted by the 3 pairs of high and low side IGBTs, not filtered, its 120 degree control where PWM only sets voltage.
The DC bus voltage ripple would be very low because I would use a pair of 470uF x 450V capacitors on the DC rail.
I will shown my current schematics regarding the BLDC motor, if that helps.