This paper presents a real time FPGA implementation of a Direct Torque Controller for Surface Mounted Permanent magnet Synchronous Motor (SPM) using PID controller. The Direct Torque algorithm with PID controller is designed and implemented using VHDL.The complete digital controller is divided into three modules. From first module position of flux vector is found based on the flux error and torque error and the sector. The torque error is obtained from PID controller. From second module the switching state of the inverter is found based on the position of the flux vector, whereas third module indicates the complete digital controller. The digital controller algorithm presented in this paper has been implemented on a Xilinx Spartan-3 FPGA board. The inverter keeps the same state till the outputs of the hysteresis controllers change states. This inverter is fed to the SPM to maintain a desired constant speed when the load varies. Experimental results on FPGA implementation of a Direct Torque Controller for SPM using PID controller are provided in this paper for two reference speeds and two load torques.
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