Switch assembly and application and control method thereof

Abstract

The invention discloses a switch assembly. The switch assembly comprises a unit chain which is connected in series with an inductor. The unit chain comprises a plurality of half-bridge active clamping units which are successively connected in series. Each half-bridge active clamping unit has a conducting state and a clamping state. When all half-bridge active clamping units are in the conducting state, the switch assembly is closed. When all half-bridge active clamping units are in the clamping state, the switch assembly is open. By clamping or turning on the half-bridge active clamping units one by one, the voltage across both ends of the switch assembly rise or fall step-by-step, which reduces the device requirement of the switch assembly. The invention discloses a modular multi-level DC/DC converter. The switch assembly replaces a single-power device in a conventional DC/DC converter to acquire the modular multi-level DC/DC converter. The device requirement in the modular multi-level DC/DC converter is reduced. The invention discloses a modulation method and a clamping capacitor voltage balancing method.

Description

technical field [0001] The invention relates to the technical field of power electronics. More specifically, the present invention relates to a switch assembly and its application and control method. Background technique [0002] High-voltage direct current (HVDC) transmission technology has been developed rapidly in these years because it is very suitable for long-distance high-power energy transmission. At present, the vast majority of HVDC transmission projects are two-terminal systems, that is, power is transmitted from one point to another without additional connection points in between. However, the high-voltage direct current grid that includes multiple transmission lines and presents a mesh structure is the development trend of direct current transmission in the future. The advantages of the HVDC grid mainly lie in optimizing the utilization of power transmission facilities, improving the flexibility of power trading and operation, and enhancing the reliability and...

AI Technical Summary

Problems solved by technology

[0006] In view of the above-mentioned defects, the present invention provides a switch assembly and its application and control method, aiming to solve the problem of series connection of the existing DC / DC converter due to the simultaneous disconnection and cut-off of the series switch tubes to realize the operation of the DC / DC converter. The voltage at both ends of the switch tube presents a very steep rising and falling edge, which makes it a technical problem with high requirements for the components in the DC / DC converter

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