Half-bridge modular multilevel single-phase inverter and modulation method

Abstract

The invention provides a half-bridge modular multi-level single-phase inverter and a modulation method. The half-bridge modular multi-level single-phase inverter comprises a capacitor bridge arm and amodular multi-level bridge arm, the modular multi-level bridge arm comprises a two-port sub-module and a multi-port sub-module, each of the capacitor bridge arm and the modular multilevel bridge armcomprises a direct-current positive end point, a direct-current negative end point and an alternating-current end point; the direct-current positive electrode end point of the capacitor bridge arm isconnected with the direct-current positive electrode end point of the modular multi-level bridge arm and is connected with the positive electrode of the direct-current power supply; the direct currentnegative terminal of the capacitor bridge arm is connected with the direct current negative terminal of the modular multilevel bridge arm and is connected with the negative electrode of the direct current power supply; the alternating-current endpoints of the capacitor bridge arms and the alternating-current endpoints of the modular multilevel bridge arms jointly form an alternating-current output port of the single-phase inverter. According to the novel nearest level approximation modulation strategy provided for the topology, accurate topology output can be achieved, and effective work of the system is maintained.

Description

technical field [0001] The invention relates to the field of direct current transmission and the field of design and control of power electronic converters, in particular to a half-bridge modular multi-level single-phase inverter and a modulation method. Background technique [0002] The rapid development of power electronic technology and the wide application of power electronic equipment have significantly improved the controllability and intelligence level of the power grid, and promoted the transformation of the power grid form. A large number of HVDC transmission lines and equipment have appeared in the AC grid. DC load and DC power distribution system will also be an important part of the future power system. In the future, there will be a situation of multi-voltage level AC and DC hybrid connection in the power system. As the core equipment of DC-AC power conversion, the steady-state and dynamic performance of the inverter will directly affect the safe and stable op...

AI Technical Summary

Problems solved by technology

This patent still has room for improvement in reducing the size of the inverter and simplifying the modulation strategy of the inverter

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