A detection method for overvoltage and undervoltage of frequency conversion fan

Abstract

The invention provides a method for detecting overvoltage and undervoltage of a frequency conversion fan, which includes a single-phase bridge rectifier capacitor filter circuit and a control chip; the single-phase bridge rectifier capacitor filter circuit and an AC power supply V AC , and output the DC bus voltage to the control chip; the AC power supply V AC The AC frequency is 50HZ or 60HZ, and the frequency rectified by the single-phase bridge rectifier capacitor filter circuit is 100HZ or 120HZ; the control chip includes a storage unit, an arithmetic unit, a timer, a fault timer, and a high-voltage counter; thereby ensuring At least one peak can be collected in each sampling period. In a single sampling period, compare the values ​​collected each time, keep the larger value, discard the smaller value, and finally get the maximum value collected in this cycle. The circuit structure of the method is simple, and the algorithm processing process of the control chip is simple and easy to operate. The error of the overvoltage and undervoltage protection voltage value is within ±2VAC from the design value under various speed regulation voltages and various static pressures, and the effect is good.

Description

technical field [0001] The invention relates to the technical field of voltage detection algorithms, in particular to a method for detecting overvoltage and undervoltage of a variable frequency fan. Background technique [0002] In the prior art, the detection algorithm for the bus voltage is generally as follows: when a fan with a declared rated input voltage of 230VAC is allowed to work normally within a voltage range of ±10%, that is, 207-253VAC. However, in order to ensure normal operation within this range, including errors and ensuring redundancy, a 5% tolerance will be added to the debugging program, that is, the overvoltage recovery voltage is 264VAC (+15%, corresponding to DC voltage 373VDC), and the undervoltage The recovery voltage is 195VAC (-15%, corresponding to DC voltage 276VDC). The voltage value of the overvoltage and undervoltage protection is a little larger than this range. Generally, such a setting is called "hysteresis". If the overvoltage recovery v...

AI Technical Summary

Problems solved by technology

[0009] Combining the above factors, the existing bus voltage sampling algorithm is affected by individual capacitors, operating environment temperature, and input AC frequency, and the difference is very large, and as time goes by, the error will become larger and larger

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