A Filtering Method Applied to Ups Bus Voltage Sampling

Abstract

For UPS, the accuracy of bus voltage sampling is particularly important. In order to effectively filter out sampling burrs caused by interference, the present invention continuously collects the sampling signal values ​​of N bus voltages and sorts them, takes two values ​​in the middle of the value and calculates their average value, which is recorded as this time The processed value avg_cur sampled from the bus voltage Udc is compared with the last sampled processed value avg_pre, and the Udc voltage change limit value Limit is set, and the value is a positive number. If avg_cur is greater than the sum of avg_pre and Limit, take the sum of avg_pre and Limit as the current bus voltage Udc; if avg_cur is less than the difference between avg_pre and Limit, then use the difference between the avg_pre and the Limit as the current bus voltage value Udc; otherwise, take the avg_cur as the current bus voltage Udc. The filtering method of the present invention is simple and practical, and can reduce the computing overhead of the CPU as much as possible so as to meet the real-time requirement of participating in the control computing.

Description

technical field [0001] The invention relates to the field of analog signal sampling and processing, in particular to a filtering method applied to UPS bus voltage sampling. Background technique [0002] With the development of information technology, UPS (Uninterruptible Power System / Uninterruptible Power Supply, uninterruptible power supply) is widely used in banking, securities, military, medical, aerospace and many other fields to protect some loads sensitive to power supply such as computer systems , communication systems, medical systems, etc. For the entire UPS system architecture, it can be said that the inverter is the core of the uninterruptible power supply system and determines the quality of the output voltage waveform. [0003] For UPS power supply, the accuracy of bus voltage sampling is particularly important, which not only affects the charging and discharging management of UPS power supply, but also affects the voltage quality of inverter control and invert...

AI Technical Summary

Problems solved by technology

When the UPS is running, it is affected by various factors, such as the sampling disturbance caused by the fluctuation of the ground level caused by internal electromagnetic interference when the whole UPS system is running, the fluctuation of the power supply of the hardware sampling circuit leads to the sampling waveform, ADC (Analog -to-Digital Converter (i.e., analog-to-digital converter) sampling itself has certain acquisition errors and other factors that will make the bus voltage obtained by sampling easy to be disturbed, especially when the load power is large, the interference is more serious, DSP (Digital Signal Processing The signal waveform sampled by the inverter) is often accompanied by very high peaks. If the sampled value of the disturbed UPS bus voltage is used directly, it will seriously affect the stability of the inverter system.

Images