Analysis And Majorization Of Single-Chip Dual-Gate Bidirectional IGBT

With the development of power electronics, industrial manufacture require the new semiconductor devices to have more flexible controllability. For example, the matrix converter has been studied for three decades because of its many unique advantages. However, its market acceptance is seriously limited by the lack of true bidirectional power semiconductor switches, which are capable of blocking voltage and conducting current in both directions.A concept of monolithic dual-gate bidirectional IGBTs (BD-IGBTs) was initially proposed by Nakagawa in 1988 with simulation results demonstrating superior performance. It can be manufactured by bonding two IGBT chips back to back or proceeding the same processing on the top and bottom sides of one single chip. This kind of bidirectional device can replace the bidirectional combo switch in ac converters, greatly reducing the component cost and stray parameters. However, depending on the two gate biasing voltages and the conduction current level, a BD-IGBT can operate in different operation modes, presenting a much more complicated control challenge than the conventional FS-IGBT. Conventional control methods, commonly used for the IGBT-diode combo switch, may no longer be applicable for the new BD-IGBT.This paper develops the physics-based device model for the BD-IGBT. Afterwards, the characteristics of BD-IGBT is analyzed and the operation modes of the new device is summarized in this paper. The influences of carrier lifetime, P well’s dosage concentration and gate structure on the forward voltage drop and turn off loss of BD-IGBT are also discussed. The parameters of BD-IGBT are optimized to reduce the power losses.The matrix converter is selected for the case study to analyze the applicability of BD-IGBT in ac converter. The power loss, efficiency, and component cost of a 13kW matrix converter are analyzed using the conventional IGBT/diode combo cell and the new single-chip BD-IGBT, respectively. A new variable-step-size control approach is proposed to maximize the benefit of the BD-IGBT, showing considerably lower switching losses. It is observed that the BD-IGBT with the new variable-step-size control approach offers 18% reduction in power loss over the conventional IGBT-diode combo approach, resulting in 0.6% improvement in efficiency in additional to component count reduction. In conclusion, the BD-IGBT exhibits significant advantages over the conventional IGBT/diode cell in efficiency and cost in same application, presenting a highly promising device option for ac converters.