On-line AC detection method and system for internal resistance of accumulator

Abstract

The invention discloses an online alternating current detection method for an internal resistance of an accumulator. The method comprises the following steps: when power is charged with stored energy or power is discharged in operation, a current signal with set frequency band passing through ripple of the accumulator is acquired, and the effective value of alternating current is calculated; when the power is charged with stored energy or the power is discharged in operation, a voltage signal with the set frequency band responding the ripple on a monomer cell of the accumulator is acquired, and the effective value of alternating voltage is calculated; and the internal resistance of the monomer cell is calculated by the effective value of the alternating current and the effective value of the alternating voltage. The invention also discloses an online alternating current detection system for the internal resistance of the accumulator adopting the alternating current detection method. With working property of power equipment, the invention provides the online alternating current detection method and a device for the internal resistance of the accumulator with simple detection means and high detection precision.

Description

technical field [0001] The invention relates to a power supply device powered by a storage battery, in particular to an on-line AC detection method and system for the internal resistance of the storage battery using the working property of the power supply equipment itself. Background technique [0002] As a backup power source for power system failures, batteries have been widely used in industries such as industrial production, transportation and communications. If the battery fails or the capacity is insufficient, it may cause a major accident, so it is necessary to carry out comprehensive online monitoring of the operating parameters of the battery. One of the important signs of the state of the battery is its internal resistance. Whether the battery is about to fail, the capacity is insufficient, or the charge and discharge are improper, it can be reflected in the change of its internal resistance. Therefore, the working state of the battery can be evaluated by measur...

AI Technical Summary

Problems solved by technology

For example: for a UPS system, the tester using the DC discharge method discharges a battery in the battery pack at 50A at a certain moment to measure the internal resistance, but at the same time, the UPS charger may be discharging the battery at 40A. To charge the battery, the tester must also take into account the influence of the charging current to accurately calculate the internal resistance of the battery

Similarly, for a tester using the AC injection method, a 100HZ 500mA current may be injected into a certain battery cell in the battery pack at a certain moment. For a common UPS storage battery, this injection may obtain hundreds of microvolts to 1 millivolts. voltage response in volts

During the operation of the power supply equipment, the voltage response to the AC current of various frequencies injected by the battery may reach hundreds of millivolts, and the internal resistance tester must accurately select the microvolts corresponding to the injected current from the background voltage of several hundred millivolts. Level response, but this usually requires complex circuits, and the accuracy is bound to be difficult to guarantee

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