DSP Based N-Motor Speed Control of Brushless DC Motors Using External FPGA Design

This paper presents n-motor speed control system of brushless DC motors for variety applications. The n-motor speed control system is implemented by interfacing an external FPGA buffering design with the PWM generation unit of the mixed signals ADSP-21992. Using this technique for the practical of variety application, N number of motors can be controlled using one DSP processor with one PWM generation unit with high performance low cost control system. The control scheme uses only one current sensor for each motor to measure the DC bus feedback current instead of two current sensors for three phase currents of each motor. Three position hall sensors are used for each motor to perform the six-step commutation technique instead of expensive decoder. Each motor speed is estimated and calculated based on hall sensors signals instead of tachometer. Theoretical derivation, simulation and experimental verification for proposed control scheme are presented in this paper. The hardware implementation is carried out based on three-phase brushless DC motors, ADSP-21992 and Vertex-E FPGA boards.