Power failure detection method

Abstract

The invention discloses a power failure detection method, which comprises the following steps of: 1, setting a sampling period, and setting a sampling number Ns in the sampling period Ts; step 2, sampling Ns three-phase line voltage instantaneous values in a sampling period, and calculating absolute values of the sampled three-phase line voltage instantaneous values; 3, judging whether the three-phase line voltage is in a power-down state or not according to the absolute value of the sampled three-phase line voltage instantaneous value; 4, according to the number of sampling periods of continuous power failure of the three-phase line voltage, the power failure types of the three-phase line voltage are judged, and the power failure types include single-phase power failure and three-phase power failure. According to the method, the collected line voltage is compared with the set threshold value and calculated in the set period, the operation condition of the power grid is deduced, the specific power-down state such as power-down of a certain phase or power-down of three phases is obtained through analysis, the power-down alarm signal and the power-down state are sent out in time, and timely adjustment of a rear-end servo system is facilitated.

Description

technical field [0001] The invention relates to the field of power-off detection, in particular to a power-off detection method. Background technique [0002] With the rapid development of power electronics technology and computer control technology, the AC speed control system composed of servo drive and servo motor has been widely used in CNC machine tools. However, in the work of CNC machine tools, there are grid voltage fluctuations and power failures to varying degrees. When the grid fluctuates abnormally or suddenly loses power, the DC bus capacitor inside the intelligent power module can be maintained for a period of time for the back-end The servo system continues to run, and the maintenance time generally lasts tens of milliseconds to one hundred milliseconds. [0003] However, if the abnormal situation of the power grid cannot be detected in time and the power failure phenomenon of the power grid side is judged, after the DC bus capacitor is exhausted, there will ...

AI Technical Summary

Problems solved by technology

However, in the work of CNC machine tools, there are grid voltage fluctuations and power failures to varying degrees. When the grid fluctuates abnormally or suddenly loses power, the DC bus capacitor inside the intelligent power module can be maintained for a period of time for the back-end The servo system continues to run, and the maintenance time generally lasts from tens of milliseconds to a hundred milliseconds

[0003] However, if the abnormal situation of the power grid cannot be detected in time and the power failure phenomenon of the power grid side is judged, after the DC bus capacitor is exhausted, there will not be enough energy to maintain the continuous operation of the back-end servo system, which will cause alarms or failures to the working whole system. , and even damage the workpiece being processed. This power failure phenomenon will not only affect the normal operation and stability of its own equipment, but also bring the risk of damage to the workpiece being processed. Electric detection, higher cost

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