Detection method for servo driver output default phase

Abstract

The embodiment of the invention relates to the field of driver state detection and discloses a detection method for servo driver output default phase. The detection method provided by the invention comprises the following steps: sampling an output current of a servo driver when the servo driver is in an enabled non-self-adjusting state, wherein the output current is a three-phase current; detecting whether the output current meets a condition I or a condition II; when the condition I is met, accumulating first duration, when the condition II is met, accumulating second duration, and when the first duration is longer than a first default phase threshold value or the second duration is longer than a second default phase threshold value, determining that one output default phase exists, wherein the condition I comprises that absolute value of one phase current is smaller than the first threshold value and that the sum of absolute values of other two-phase currents is higher than the second threshold value, and the condition II comprises that an effective current is higher than a third threshold value, and that absolute value of one phase current is smaller than the first threshold value. When the method is used for judging whether one output default phase exists, misjudgment probability is greatly reduced, and default phase judgment accuracy is enhanced.

Description

technical field [0001] The embodiment of the present invention relates to the field of driver state detection, and in particular to the detection technology of output phase loss of a servo driver. Background technique [0002] Servo drives are devices used to precisely control the torque, speed and position of servo motors. The servo driver stores rectified and filtered DC power or externally input DC power in the internal capacitor, and then uses the inverter unit to convert the DC power into 3-phase AC power and output it to the servo motor. Indirectly control the torque, speed and position of the servo motor by controlling the frequency and amplitude of the output voltage and current, such as figure 1 shown. [0003] If more than one phase is disconnected between the output of the servo driver and the UVW phase line of the servo motor, it is called output phase loss. The reasons for the output phase loss include: a. The cable between the servo drive and the servo motor...

AI Technical Summary

Problems solved by technology

The inventors of the present application have found that there are at least the following problems in this method: Problem 1: the criterion is related to the frequency of the output current

At low frequency, the current stays near 0 for a long time, which may cause misjudgment; Question 2: The limit case of Question 1 is that the output frequency is 0, that is, when the shaft is locked, if the current of a certain phase is just close to 0, it may cause misjudgment. Judgment; Question 3: The sinusoidal current generated by the PWM method contains more harmonics, and the harmonics may be sampled to cause misjudgment

The inventors of the present application have found that this method has at least the following problems: this method can complete the phase loss judgment when the three phases are all sine waves, but the output current waveform of the servo is not a pure sine wave, especially at high speeds. Judgment failure due to harmonics in the sampling current

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