Single-phase three-level inverter circuit

Abstract

The invention discloses a single-phase three-level inverter circuit which comprises a bus, a first power switch module 1, a second power switch module 2, a third power switch module 3, a fourth power switch module 4, a fifth power switch module 5, a sixth power switch module 6, a first diode D1, a first inductor L1 and a second inductor L2. Or the fifth power switch module 5 and the sixth power switch module 6 are replaced by a seventh power switch module 7 and an eighth power switch module 8. The first power switch module 1 to the eighth power switch module 8 respectively comprise a main power switch and an auxiliary circuit. The auxiliary circuit is unidirectionally conducted when the main power switch is conducted, and reverse current is prevented from flowing through the main power switch. The auxiliary circuit for protecting the main power switch is added, the main power switch is prevented from being attacked by reverse current, the service life of a device is prolonged, the stability of the circuit is improved, soft switching of the main power switch can be achieved, and the working efficiency of the inverter is improved.

Description

technical field [0001] The invention relates to the field of inverters, in particular to a single-phase three-level inverter circuit. Background technique [0002] Inverters are widely used in new energy power generation and energy storage systems. Its working principle is to convert direct current (photovoltaic panels, batteries) into alternating current through an inverter circuit. With the gradual advancement of the national strategy of building distributed power stations, the application of single-phase inverters in photovoltaic and energy storage systems is becoming more and more extensive. The commonly used topologies of inverters used in single-phase photovoltaic and energy storage systems mainly include H full bridge, Heric topology, and H5 topology. [0003] H full bridge is the most common inverter topology, and its control methods mainly include unipolar modulation and bipolar modulation. Compared with bipolar modulation, unipolar modulation has less switching l...

AI Technical Summary

Problems solved by technology

Since the inverters used in photovoltaic or energy storage systems have the requirement of generating reactive power, the switch tubes currently used in photovoltaic and energy storage inverters are mainly IGBT (Insulated Gate Bipolar Transistor, Insulated Gate Bipolar Transistor, Insulated Gate Bipolar Transistor, Pole transistor), although IGBT has lower conduction loss than MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, Metal-Oxide-Semiconductor Field-Effect Transistor), its large switching loss and tail current loss also limit its Difficult to apply to higher switching frequencies

Therefore, it also limits the development of photovoltaic and energy storage inverters to higher power density

Images