lewood
Newbie level 3
Hi all,
Can somebody please clarify what a 4 quadrant drive is when used in brushless dc motor servo control. My understanding has always been that this drive allows control in all four quadrants of operation (+ve and -ve torque with +ve and -ve speed). I have read a few articles now that seem to go one step further and classify 4 quadrant control as allowing control in all four quadrants but also more specifically modulating the diagonally opposing switches in the bridge in the off period of the PWM. I understood this to be locked anti phase method of controlling the PWM. As far as I can tell, allowing the inductor to discharge to the supply through the flyback diodes in the off period rather than switching on the opposing switches on will still give four quadrant control (although discontinuous operation will degrade performance when current levels are low).
Any thoughts?
Can somebody please clarify what a 4 quadrant drive is when used in brushless dc motor servo control. My understanding has always been that this drive allows control in all four quadrants of operation (+ve and -ve torque with +ve and -ve speed). I have read a few articles now that seem to go one step further and classify 4 quadrant control as allowing control in all four quadrants but also more specifically modulating the diagonally opposing switches in the bridge in the off period of the PWM. I understood this to be locked anti phase method of controlling the PWM. As far as I can tell, allowing the inductor to discharge to the supply through the flyback diodes in the off period rather than switching on the opposing switches on will still give four quadrant control (although discontinuous operation will degrade performance when current levels are low).
Any thoughts?