Digital wave-by-wave current limiting system and protection method based on fpga

Abstract

The invention provides an FPGA-based digital wave-by-wave current limiting system which comprises the components of a current measurement circuit, an electric power electronic switch device, a switch device driving circuit, an analog conversion circuit, an AD conversion circuit and an FPGA chip, wherein switch device current which is detected by the current measurement circuit is converted to a signal which is suitable for acquisition of the AD conversion circuit through the analog conversion circuit. The signal is then converted to a digital signal by the AD conversion circuit. The FPGA chip acquires the digital signal, performs overcurrent judgment and outputs a pulse width signal duty ratio to the switch device driving circuit to the switch device driving circuit for driving the electric power electronic switch device. According to the FPGA-based digital wave-by-wave current limiting system, a digital method is utilized for realizing wave-by-wave current suppression; high operating speed of the FPGA can be realized, wherein the operating speed can reach dozens of MHz and relatively high calculating function is realized; and a more complicated algorithm and a high-efficiency fault tolerance mechanism can be added into the wave-by-wave current limiting function, so that the wave-by-wave current limiting system has higher flexibility, higher safety and higher reliability.

Description

technical field [0001] The invention relates to the field of overcurrent protection of power electronic switching devices, in particular to an FPGA-based digital wave-by-wave current limiting system and protection method. Background technique [0002] With the continuous development of power electronic devices and control technology, power electronic conversion systems have been widely used in industrial electrical drives, transportation, power systems, communication systems, and new energy fields. Moreover, the voltage level and current level of switching devices are getting higher and higher, and there are also strict requirements for the safe and stable operation of power electronic conversion systems. In practical applications, short circuit or sudden fluctuation of current may occur in the main circuit. Although the overcurrent protection circuit provided by the power electronic device itself can be used to realize the judgment of overcurrent, and the control system can...

AI Technical Summary

Problems solved by technology

In practical applications, short circuit or sudden fluctuation of current may occur in the main circuit. Although the overcurrent protection circuit provided by the power electronic device itself can be used to realize the judgment of overcurrent, and the control system can complete the blocking of the switching device, but the power electronic device The threshold value of its own overcurrent protection is high, and it cannot be adjusted flexibly. At the same time, due to the inherent time delay of the blocking circuit and the control system, it will also lead to a longer execution time of the protection process.

Therefore, when an overcurrent problem occurs, it will have a great impact on the overcurrent impact of power electronic switching devices

[0003] The ideal way is to adopt the method of wave-by-wave current limitation, but the current implementation method of this technology is mainly based on the realization of analog circuits. Compared with the timing sampling using microprocessors, the speed of analog circuits is fast and can Realize the current limiting function, but the analog circuit also has the following problems: (1) The design of the analog circuit is relatively complicated, and it is not easy to upgrade later

And when the analog circuit realizes the wave-by-wave current limiting protection of multiple switching devices, each device needs to be configured with an independent circuit, which increases the complexity of the system

(2) It is difficult for analog circuits to implement complex algorithms and fault-tolerant functions

(3) In the analog circuit, once the overcurrent value, overcurrent return value, and minimum pulse width value are set, they cannot be modified online, and complex information is difficult to interact with the microprocessor

(4) The analog circuit only completes the wave-by-wave current limiting function, and the control system still needs

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