Concatenated multilevel inverter circuit capable of realizing energy feedback and control method

Abstract

The invention discloses a concatenated multilevel inverter circuit capable of realizing energy feedback and a control method. The circuit is formed by concatenating power units based on a three-phase uncontrolled rectifier circuit and power units based on a three-phase pulse width modulation (PWM) rectifier circuit. The control method provided by the invention comprises the following steps of: controlling the switching-on of insulated gate bipolar transistors of inverter circuits in the power units based on the three-phase uncontrolled rectifier circuit to make the feedback energy of a load not flow into intermediate direct current voltage circuits in the power units based on the three-phase uncontrolled rectifier circuit but directly flow into intermediate direct current voltage circuits in the power units based on the three-phase PWM rectifier circuit. The circuit provided by the invention can realize a load energy feedback power grid to achieve an energy saving effect, simultaneously simplifies the complexity of a topology structure of a power unit system and a control link to a certain extent and decreases the number of the insulated gate bipolar transistors, thereby decreasing the construction cost, and has high economic value.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a cascaded multilevel inverter circuit and a control method thereof. Background technique [0002] With the development of power electronics technology, high-voltage frequency converter is one of the main achievements of power electronics technology development. Because of its high power factor, high efficiency, high precision and wide speed range, it is widely used in various fields of national economy, such as metallurgy, Mining, petrochemical, electric power and other industries have been widely used and are playing an increasingly important role. [0003] At present, most of the general-purpose high-voltage inverters on the market are single-quadrant inverters, and their main circuit topology mostly uses power units based on uncontrolled rectification circuits to form a cascaded multi-level inverter circuit structure. The circuit of traditional cascaded ...

AI Technical Summary

Problems solved by technology

However, the PWM rectifier control circuit needs to detect the amount of information such as the AC side current and the DC side voltage to implement the PWM rectification control algorithm, which increases the cost in the detection and control link and also increases the complexity of the system control, which also brings a negative impact on the reliability of the system. Negative Effects

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