Filtering method applied to UPS bus voltage sampling

Abstract

For a UPS, the bus voltage sampling precision is particularly important. In order to effectively filter out sampling burrs caused by interference, the invention discloses a filtering method applied toUPS bus voltage sampling. The filtering method comprises the steps of: continuously acquiring sampling signal values of N bus voltages, ranking the sampling signal values, taking two values with thenumerical values in the middle, calculating an average value of the two values, recording the average value as a processing value avg_cur for sampling the bus voltage Udc at this time, comparing the processing value avg_cur with a last sampling processing value avg_pre, and setting a Udc voltage change amplitude limit value Limit as a positive number; if the avg_cur is greater than a sum of the avg_pre and the Limit, taking the sum of the avg_pre and the Limit as a bus voltage Udc of this time; and if the avg_cur is smaller than a difference between the avg_pre and the Limit, taking the difference between the avg_pre and the Limit as a bus voltage value Udc of this time; otherwise, taking the avg_cur as a bus voltage Udc of this time. The filtering method provided by the invention is simple and practical, and can reduce the operation overhead of the CPU as much as possible so as to meet the real-time requirement of participating in control operation.

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 (ie Uninterruptible Power System / Uninterruptible Power Supply) is widely used in many fields such as banking, securities, military, medical, aerospace, etc. to protect some sensitive loads such as computer systems. , Communication systems, medical systems, etc. For the overall system architecture of UPS, 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 supplies, the accuracy of bus voltage sampling is particularly important. It not only affects the charge and discharge management of UPS power supplies, but also affects inverter control and the voltage quality of inverter output. The inverter output waveform is ...

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.

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