Short-circuit protection device and method for I-type three-level APF

Abstract

The invention provides a short-circuit protection device and method for an I-type three-level APF. The device and method can achieve switching-off of an outer tube and an inner tube, and achieve short-circuit protection. The device comprises a topology circuit; the topology circuit comprises IGBT T1 to T4, freewheel diodes D1 to D4, and clamping diodes D5 and D6; IGBT T1 and T4 are used as outer tubes; IGBT T2 and T3 are used as inner tubes; the device further comprises short-circuit fault detection circuits, a fault signal logic circuit and a driving signal logic circuit; a short-circuit fault detection circuit is connected between the collector and the emitter of each IGBT; the output ends of the short-circuit fault detection circuits are connected with the input end of the fault signallogic circuit, and the output end of the fault signal logic circuit is connected with the input end of a driving signal logic circuit; the short-circuit fault detection circuits are used for generating fault signals corresponding to the IGBTs; the fault signal logic circuit is used for summarizing the fault signals sent by the IGBTs T1 to T4 to generate a total fault signal; and the driving signallogic circuit is used for realizing delayed turn-off of the IGBT T2 and the IGBT T3 which are used as the inner tubes.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a short-circuit protection device and method for an I-type three-level APF. Background technique [0002] With the continuous development of solar energy and UPS technology and the continuous expansion of the market, manufacturers are paying more and more attention to the requirements for inverter efficiency. Therefore, the three-level topology has emerged. As we all know, it is different from the traditional Compared with the two-level structure, the three-level structure not only halves the blocking voltage of a single IGBT tube, but also has the advantages of small harmonics, low loss, and high efficiency. Therefore, the three-level APF has been widely used; among them, In practical applications, when a short-circuit fault or an over-current fault occurs, the I-type three-level APF needs to turn off the outer tube first, and then turn off the inner tube. The reasons ...

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Problems solved by technology

[0004] (2) If the inner tube is turned off first, the inner tube IGBT will bear the entire bus voltage, and the inner tube will be damaged due to overvoltage. Usually, the IGBT will break down due to overvoltage, and the subsequent explosion of the module may occur;

[0006] Based on this, the traditional fault protection method of I-type three-level APF is to use the built-in short-circuit protection detection module in the driver IC chip, which can immediately close the fault tube after detecting the fault signal, and at the same time transmit the fault signal to the MCU , trigger an interrupt, and the MCU will turn off the rest of the tubes. The delay of the transmission signal plus the interrupt response time is generally more than ten microseconds or even longer; however, when a short circuit occurs in the inner tube, the inner tube will give priority to itself shut off, it is impossible to close the outer tube first and then the inner tube

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