Current control methods to protect against abnormal operation of permanent-magnet synchronous motor

Abstract As the single-phase asynchronous motor, the permanent-magnet synchronous motor in the actual use process may be in an abnormal working state due to the bad use environment, large load impact, and other fault reasons. Abnormal operation of the motor for a long time will not only lead to motor wear, demagnetization, or gridlock but also have a great impact on the load and test system driven by the motor. In order to meet the characteristics of high stability and low loss during the operation of the motor, this paper proposes two current control methods for the abnormal operation of the motor. The methods can continuously monitor and collect the three-phase phase current of the motor through the software of variable frequency controller and determine whether the motor is in a state of abnormal operation timely and accurately according to the detected phase current data. Using the current control methods through the variable frequency controller can effectively come true to the purpose of stopping the motor when it is in abnormal operation. The experimental results show that the methods proposed in this paper can be flexibly applied to any permanent-magnet synchronous motor of any structure, which not only can minimize the risk of motor burnout or damage but also significantly improve the stability of the test system. Compared with the traditional current control method, it has the advantages of high intelligence, excellent reliability, and strong safety.