Capacitor operation state online monitoring method based on PCB Rogowski coil

Abstract

The invention discloses a capacitor operation state online monitoring method based on a PCB Rogowski coil. The method uses a PCB Rogowski coil as a current sensor for online monitoring, and comprisesthe following steps: (1) designing a corresponding PCB Rogowski coil according to an actually monitored capacitor, and sleeving the PCB Rogowski coil on any pole of the capacitor to measure ripple current of the capacitor; (2) obtaining ripple voltage and DC voltage of the capacitor by using an isolation operational amplifier; (3) filtering the ripple current and the ripple voltage and inputting the ripple current and the ripple voltage into a microcontroller; (4) measuring the temperature of the capacitor shell to indirectly obtain the core temperature of the capacitor; (5) looking up a tableor calculating to obtain an ESR initial value at the core temperature of the capacitor in step (4); and (6) calculating the ripple voltage and the ripple current of the capacitor to obtain the real-time ESR of the capacitor, comparing the real-time ESR with the initial ESR to obtain the operation state of the capacitor, and finally transmitting the information to a data center. According to the invention, the operation state of the capacitor can be monitored in real time.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to an online monitoring method for capacitor operating states based on PCB Rogowski coils. Background technique [0002] Capacitors are an integral part of most power electronic devices. According to statistical analysis, the failure of power electronic equipment is mostly due to the damage of capacitors, especially electrolytic capacitors. In order to avoid greater losses after capacitor failure, it is best to replace the capacitor before it is about to fail. The reliability and expected life of the device are studied. At present, the reliability and life prediction of capacitors are mostly based on various technical manuals and life prediction models, but the actual reliability and life estimates based on technical manuals and life prediction models are very different from the actual ones. Therefore, it is necessary to monitor the state of capacitors. The m...

AI Technical Summary

Problems solved by technology

Among them, the calculation method based on the circuit model is greatly affected by the various devices in the circuit. The change of any factor will lead to the change of the actual transmission information, and the final result will also deviate greatly from the actual; the sensor-based measurement method often uses additional The sensor measures the ripple voltage and ripple current of the capacitor, and then obtains the capacitance and ESR of the capacitor, but most methods use an external power supply and the sensor is large in size, which causes inconvenience in practical application and is not conducive to Large-scale promotion and application; the advanced algorithms based on data mostly adopt methods such as adaptive neuro-fuzzy reasoning system. Although the actual detection results are good, the technology is not mature and cannot be widely used

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