Bypass control method for fault power module of modular multilevel converter

Abstract

The invention discloses a bypass control method for a fault power module of a modular multilevel converter. The bypass control method comprises the following steps that 1), enabling the fault power module of the modular multilevel converter to execute an instruction for triggering a bypass operation; 2), judging whether a current value Iarm of a bridge arm of the modular multilevel converter where the fault power module is located exceeds a current protection fixed value Iarm_MAX of the bridge arm or not: if yes, executing the step 3), or executing the step 4); 3), executing all power module instructions of the bridge arm of the modular multilevel converter where the temporary blocking fault power module is located; 4), judging whether the fault power module completes an instruction of bypass operation or not: if yes, determining that the bypass control of the fault power module is successful. According to the method, the requirements of the bypass function of the power module on the capacitance capacity in the power module and the switching-on speed of a bypass mechanical switch can be effectively reduced, the size and the cost of the modular multilevel converter are reduced, and the reliability is improved.

Description

technical field [0001] The invention relates to the technical field of bypass control of converter power modules, and more particularly, to a bypass control method for a faulty power module of a modular multilevel converter. Background technique [0002] With the increasing shortage of fossil energy and environmental pollution, people's demand for access to distributed renewable clean energy such as wind power and solar energy is becoming more and more urgent. The high-voltage power supply based on voltage source converter (VSC) On the one hand, the DC transmission system has the characteristics that the active and reactive power can be independently and flexibly controlled. On the other hand, the HVDC transmission system can supply power to the passive system. The waveform quality is good, and the voltage polarity does not need to be changed when the power flow is reversed. Access to renewable energy provides an effective solution. Among them, the modular multilevel conver...

AI Technical Summary

Problems solved by technology

However, limited by the low overvoltage level of the power module and the slow bypass speed (generally not less than 5ms), the bridge arm current will still pass through the anti-parallel diode in the upper side IGBT during the bypass process of the faulty power module. It flows into the capacitor of the faulty module and raises the voltage of the faulty power module. In order to protect the safe exit of the faulty power module, most of the power module capacitors are still reserved in the existing project

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