A sensor-less four-phase BLDC fan for automotive engine cooling applications was accomplished. By means of special design of free-wheeling circuits, the energy stored in the motor winding can be effectively dissipated during the switching off of the power switches, thus effectively alleviating the EMC problems. Moreover, the protection of polarity reverse fault was also accomplished in the system. In order to further improve the reliability, a sensor-less control strategy based on EMF zero-crossing detection method with software sampling was put forward and applied to the fan system. Experimental results were presented to validate the feasibility of the ayatem.%针对汽车引擎冷却应用实现了一种新型三相半波无刷直流风机系统.该控制系统通过特殊续流电路设计,可在逆变器功率开关器件关断时为无刷直流电机绕组储能提供良好的续流通路,有效避免由于较高感应电势导致的电磁干扰问题.同时,该控制器具有电源反接保护功能,可以避免由于电源极性反接导致的大电流故障.为了进一步提高该风机系统的可靠性,采用基于软件实时采样反电势过零点的方法实现了无位置传感器控制,进一步简化了系统结构、提高了可靠性.最后,给出了试验结果,验证了这一方案的可行性.
展开▼
