Protection control method of transformer power module with short-circuit protection unit

Abstract

The invention discloses a protection control method of a transformer power module with a short-circuit protection unit. In the method, a three-phase two-level space vector modulation manner is adopted for the transformer; a PWM (Pulse Width Modulation) unit outputs PWM waves to control on / off of the transformer power module; and after a command of outputting the PWM waves is received, the PWM control unit selects any two non-complementary basic voltage space vectors to regulate the pulse widths of the PWM control unit firstly participating in output modulation to preset pulse widths more than or equal to the detection time of the short-circuit protection unit; and if the short-circuit protection unit does not produce a protection action in the turn-on time of the pulse width, subsequent PWM waves are output, and if the short-circuit protection unit produces the protection action in the turn-on time of the pulse width, the output of the PWM waves is locked. The method disclosed by the invention has the advantages that the short-circuit protection unit can effectively detect the conditions of any two phases of short circuits at an output side, and effectively prevents the situation that a fault is extended because the transformer cannot detect the command of outputting the PWM waves in time due to short circuit when the command is received.

Description

technical field [0001] The invention relates to a control method for a converter power module, in particular to a protection control method for a converter power module with a short-circuit protection unit, and belongs to the technical field of power electronics. Background technique [0002] Power semiconductor modules have been widely used at home and abroad in recent years. At present, low-voltage two-level inverters on the market use power modules. While power modules are widely used, in order to improve product reliability, people pay more and more attention to the protection of power modules. The application practice shows that the short circuit is a frequent failure of the power module in the power circuit, and it is also one of the main reasons for the damage of the power module. The power module is a high-frequency switching device, and the internal current density of the chip is very large. When a short circuit occurs, its internal temperature rises rapidly, resul...

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Problems solved by technology

[0003] However, the protection units of most converter power modules have a certain range of protection blind zones

The protection blind zone refers to: the short-circuit protection circuit buffer time of the protection unit of the power module causes the protection action of the protection unit of the power module to be untimely, and (or) the rising rate of the short-circuit current is relatively slow due to some external reasons, resulting in The module has been damaged due to long-term overload before the protective unit protection action

[0004] For the above-mentioned latter protection blind zone, there are two possible reasons for this situation: one is due to the existence of inductance in the short-circuit circuit on the load side, the short-circuit current rises slowly, and rises to the protection of the power module after a long period of time. The protection threshold set by the unit triggers the short-circuit protection. At this time, the power module is likely to be damaged due to the rapid rise of the internal junction temperature due to the short-circuit current for a long time

[0005] Second, when the short-circuit current on the load side continuously outputs a small pulse width, the rising speed of the short-circuit current is limited, which may cause the power module to withstand the short-circuit current for a long time before the short-circuit current reaches the threshold rapid rise in junction temperature and damage

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