A method for equalizing device loss of sic MOS MMC sub-module

Abstract

The invention discloses a method for equalizing the device loss of SiC MOS MMC sub-modules. The working modes of the sub-modules are divided into synchronous rectification mode and non-synchronous rectification mode. Based on the channel bidirectional conduction characteristics of SiC MOSFET, through continuous Adjust the current threshold, so that the two working modes can be adaptively converted in the whole working cycle, thereby adjusting the proportion of the two working modes in the whole working cycle, so as to minimize the loss of the MMC sub-module device. This method is controlled by the device From the perspective, without changing the output power quality of the converter, using the characteristics of the SiC MOSFET channel to conduct current bidirectionally, the balance of the loss of the sub-module devices will be achieved under the condition that the output waveform of the MMC remains unchanged, and will not cause damage to the top-level control of the MMC system. In addition, this method does not need to add additional power devices, is suitable for the most basic half-bridge sub-module topology, is not limited by the topology, and can achieve loss balance within the full power factor range of ‑π / 2 to π / 2 , with rich application scenarios.

Description

technical field [0001] The invention belongs to the field of voltage converters, and more specifically relates to a method for equalizing the loss of SiC MOS MMC sub-module devices. Background technique [0002] Modular Multilevel Converter (MMC) has broad application prospects in DC transmission, motor drive, and renewable energy integration due to its good modularity, flexible scalability, and good waveform quality. . In order to adapt to the operation requirements of complex application scenarios and environments, the efficiency, cost, and environmental adaptability requirements of MMC are gradually increased. At present, Si-based devices are generally used as switching devices in MMC sub-modules. However, traditional Si-based devices belong to the first generation of devices, which have high losses and are difficult to operate in a high temperature environment above 125°C. It is difficult to further improve the transmission efficiency and need to sacrifice a lot of volu...

AI Technical Summary

Problems solved by technology

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a method for equalizing the loss of the SiC MOS MMC sub-module device, which is used to solve the problem that the existing method will affect the output power quality of the MMC after loss equalization due to the change of the modulation strategy of the system technical issues

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