Photovoltaic inverter protection device and method based on CPLD (complex programmable logic device)

Abstract

The invention discloses a photovoltaic inverter protection device and method based on a CPLD (complex programmable logic device). A CPLD logic control unit is provided with a CPLD chip; the CPLD chip is provided with 16 first-class fault detection pins, 26 second-class fault detection pins, 6 PWM (pulse width modulation) signal output pins, a signal sending pin in the case of first-class faults and a signal sending pin in the case of second-class faults, wherein the first-class and second-class fault detection pins are connected with a second-class fault acquisition unit respectively; the DSP chip samples a voltage / current sampling signal according to a voltage / current sensor and generates a PWM wave and inputs the PWM wave into the CPLD chip; in the case of first-class faults, the DSP chip gives an alarm and cuts the PWM wave signal; and in the case of second-class faults, the DSP chip gives an alarm and does not cut the PWM wave signal. The device and method disclosed by the invention can collect multiple fault signals at the same time and classify the first-class and second-class faults, and quickly take corresponding protection alarm measures respectively so as to improve the reliability and stability of a photovoltaic inverter.

Description

technical field [0001] The invention discloses a CPLD-based photovoltaic inverter protection device, which belongs to the technical field of photovoltaic power generation. Background technique [0002] CPLD (Complex Programmable Logic Device, Complex Programmable Logic Device) is a digital integrated circuit in which users can construct logic functions according to their own needs. The basic design method is to use the integrated development software platform to generate corresponding target files by means of schematic diagrams and hardware description languages, and transmit the code to the target chip through the download cable ("online system" programming) to realize the designed digital system. . [0003] In a photovoltaic grid-connected system, perfect protection functions play a vital role in the good operation of the system, among which the protection of the inverter is the most critical. The main circuit of the photovoltaic inverter is powered by the solar cell arr...

AI Technical Summary

Problems solved by technology

[0006] DSP is used for protection, and the types of faults are not classified during the protection process, and because DSP has to complete other control functions of the system, the general I / O expandability of DSP itself is limited, and it cannot meet the detection function of multiple fault types

In addition, the DSP sampling frequency and alarm speed are not timely compared with the occurrence time of a type of fault [Microsoft user 1], which makes the reliability and stability of the photovoltaic inverter system worse

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