The Research On The Voltage Balancing Technology Of Series-Connected IGBTs

The power switch is one of the most important components in the pulse power system. The opening switch is the key technology to the development of the inductance stored energy pulse power in order to get the ideal quick pulse output with high power and steep rise. Under the premise of comparing various opening switches, IGBT becomes one of the pulse power switch’s best choices for its high input impedance, low drive power, high frequency and good switch characteristic. With the development of the modern power electronic technology, the voltage rank of a single IGBT was relatively low, which makes its application and development extremely limited. IGBT series can quickly meet the voltage rank requirement of the whole devices. Therefore, the study for the application of the IGBT series has very important practical significance.The IGBT series application is practical and feasible. Compared with a high single one, simulation analysis shows the superiority of the low-power IGBT series in the switch motion time, the switch energy loss, the collector over-voltage and the switch frequency with the OrCAD/PSpice software. As for the static and dynamic voltage unbalancing in the operation of the IGBT series, the paper shows simulation analysis from the differences of the individual performance and the outer circuit parameters (the absorption capacitance, the gate resistance, the IGBT parasitic inductance and the gate drive signal delay, etc). Some of the IGBT series voltage balancing technologies are summarized, which are divided into the load side passive voltage balancing technology and the gate side active voltage balancing technology. The advantages and disadvantages of various methods are analyzed, as well as the basic principles.On the foundation of the above analysis, a kind of hybrid voltage balancing control circuit is optimized, which is simple and reliable with few components as a whole. The simulation analysis and experiments show that it can suppress the surge voltage well at the switch motion instant, protecting the series IGBT against the overvoltage from breakdown damage, and then it can avoid the entire series circuit of failure.