电网瞬时停电保持变频器母线电压的新方法

Novel Method of Maintaining D.C. Link Voltage of Inverter in Power Interruption

工业现场中,变频器带大惯性负载运行时,有时会遇到电网瞬时停电的情况,由于负载惯性大,电网瞬时停电再来电后,电机不能立即起动运行。针对这种情况,提出了一种新的解决方法:瞬时停电后,变频器有规律地降频运行,使异步电动机进入微发电状态,电机与变频器构成一个自治系统,以维持变频器母线电压。来电后,变频器从当前运行频率处,再恢复到额定运行状态。对所提出的方案,在山东新风光电子科技发展有限公司生产的JD?BP32变频器上进行了试验,试验结果验证了控制方案的正确性。

Power interruption sometimes occurs in industrial process where inverters are operating with large inertial load. Due to the large inertial load, the induction motor cannot be restarted up when power supply comes back. This article proposes a new method to solve this problem. In the process of power interruption the inverter reduces the operate frequency regularly to make the induction motor enter into the slightly generating mode and then the induction motor and the inverter make up of an autonomous system to maintain the d.c. link voltage of the inverter. When power supply comes back, the inverter recovers to rated operate state from the current operate frequency. The proposed method is tested with JD-BP32 inverter made by Shandong Xin Fengguang Electronic Science and Technology Development Ltd. and the correction of the control strategy is verified.