A low cost brushless DC motor drive

This paper presents a low cost drive technique that allows three phase brushless DC machines to be driven without a DC link capacitor. The proposed technique uses a unique switching sequence and operates the machine without the intermediate DC link capacitor. The paper details the derivation of the switching sequence and presents a model for the motor drive in Matlab/Simulink environment. The performance of the technique is evaluated using a model of 320 W BLDC machine, which is operated in both torque and speed control modes, and simulated results indicate that the performance of the machine is comparable to existing techniques. The proposed technique is to implement, low in cost without a DC link capacitor, and would be attractive for low cost application where torque ripple is not a concern.