Maximize Motor Efficiency with Encoder Feedback
When comparing all the different types of electric motors currently available; the Permanent Magnet Brushless DC Servomotor (PMBDC) can provide the highest continuous torque density (i.e., torque output per unit volume) along with the highest power efficiency compared to any other type of electric motor. Hence, as design engineers constantly seek to select and use the smallest possible, least costly, and most highly efficient electric motor for their increasingly demanding applications the PMBDC motor is becoming the preferred choice. However, as described in this paper, to obtain maximum continuous torque output and power efficiency from a PMBDC motor one must use the proper feedback and control method that allows the Drive to keep each phase-current "in phase" with the motor's corresponding back EMF/Torque function(s). Hence, the purpose of this paper is to discuss how optical encoder feedback is used in combination with the Drive Electronics to maximize the continuous torque output and power efficiency that each PMBDC motor is capable of producing.