Method and circuit for online monitoring capacity state of bus capacitor

Abstract

The invention discloses a method for online monitoring the capacity state of a bus capacitor. According to the method, a capacitor current real-time value ic and a capacitor voltage real-time value Uc of the bus capacitor in the charge / discharge process are detected in real time; as the bus capacitor C is a function of the capacitor current ic, the capacitor voltage Uc and time t, the capacitor capacity is estimated according to the functional relationship; and the capacity state of the bus capacitor is monitored online by judging whether the estimated value of the capacitor capacity is normal. The method can discover the performance drop of the capacitor and possible failure caused by the performance drop in time and does not require forced regular replacement of the bus capacitor, thereby reducing the maintenance cost; and moreover, as the method does not have low requirement on the maintenance personnel, the maintenance cost and the technical difficulty in maintenance are reduced.

Description

technical field [0001] The invention relates to a detection circuit of bus capacitance, in particular to a method and circuit for on-line monitoring of the state of bus capacitance. Background technique [0002] A capacitor is a component that can store charges, and it is also one of the most commonly used electronic components. In the field of power electronics technology, capacitors are used in almost all power electronic circuits. Such as Picture 1-1 with Figure 1-2 As shown in the circuit of , the role played by the capacitor in the circuit is the basic charge and discharge function. by Picture 1-1 For example, first the soft start switch K2 is closed, the input switch K1 is opened, the input voltage Us charges the bus capacitor C through K2 and the soft start resistor R, and when the bus capacitor Uc reaches a certain value, the input switch K1 is closed to complete the soft start of the bus capacitor. Boot process. Figure 1-2 In the circuit, first the soft start...

AI Technical Summary

Problems solved by technology

[0004] Bus capacitors are generally high-voltage and large-capacity electrolytic capacitors, which are expensive, and the cost of regular replacement is high. In addition, testing equipment is required, which requires high maintenance personnel. In addition, manual testing has low efficiency and low accuracy. Timely replacement, there is a greater safety hazard

Images