Method for controlling desaturation detection protective circuit in T-shaped three-level inverter

Abstract

The invention relates to a method for controlling a desaturation detection protective circuit in a T-shaped three-level inverter. The method comprises the steps of: analyzing and judging an output voltage current signal of the inverter through sampling, filtering, amplifying and comparing circuits by a digital signal processor to determine the direction of the output voltage current; sorting the output state of voltage current combination in different directions: area I (v)0,i)0), area II (v)0,i(0), area III (v(0,i(0) and area IV (v(0,i)0), respectively; then judging the positive and negative semi-cycle reversing condition in each state of current, including positive reversing to negative reversing and negative reversing to positive reversing; carrying out enabled logic control on the desaturation detection protective circuit of a switch under different output states and current reversing conditions; and receiving an enabled control signal by a switching drive chip or a peripheral circuit, so that a desaturation detection function is alternately activated and inhibited when the inverter converts and inverses. The method avoids a spurious triggering fault of the desaturation detection circuit caused by factors such as oscillation in the converting and reversing process of the T-shaped three-level inverter, and the reliability of fault diagnosis by the system is effectively improved, so that the normal work of the circuit is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of power electronic equipment, and in particular relates to a control method for a desaturation detection and protection circuit in a T-shaped three-level inverter. Background technique [0002] In recent years, solar power generation technology represented by photovoltaic power generation has been widely promoted and supported by various countries. China's "Twelfth Five-Year Plan" plans that by 2015, China's total photovoltaic installed capacity will reach more than 40GW. As the most important link in the photovoltaic power generation system, the inverter directly determines the efficiency and reliability of photovoltaic power generation. As the three-level inverter gradually replaces the two-level inverter, the efficiency and output power quality of the inverter have been greatly improved, and it is also faced with more complex control circuits and higher reliability requirements. [0003] In current thre...

AI Technical Summary

Problems solved by technology

However, the voltage value of this terminal is easily affected by other IGBTs and commutation during the current commutation process of the T-shaped three-level inverter, and circuit oscillation and other phenomena occur.

These phenomena will cause the terminal voltage to rise, causing the driver chip to misjudge and trigger by mistake, thereby performing false short-circuit protection actions, affecting the normal operation of the three-level inverter and reducing system reliability.

Images