High Efficient BLDC Controller for Automobile Cooling Fan

This paper presents a design of a BLDC (Brush less Direct Current) controller in the automobile engine cooling fan system which has the independent intellectual property. The controller mainly focuses on the control of a four phase sensor less BLDC motor with bifilar windings. The half-wave circuit is adopted, and it can also achieve the demand of high torque performance and similar effect compared with the full-bridge circuit, so the controller has the advantages of low cost, high efficiency and high reliability. Meanwhile, a multi-task operation algorithm applied in automotive electronic controller is designed in the system. By using the time-based multi-task operation, the tasks, including out of step protection, over-current protection, over/under voltage protection, open/short circuit protection and communication diagnose are separated according to their priority. The arbitration unit commands all the tasks, so, the high reliability and real-time demands of cooling fan controller in automotive application can be satisfied. The whole system has been tested and the results achieve the anticipation.