A novel IGBT gate driver to eliminate the dead-time effect

The IGBT switching dead time which prevents the DC link shoot-through of the voltage source converter causes problems such as the waveform distortion and the fundamental voltage loss of the converter output. To solve these problems, many dead-time compensation methods, most of which are implemented within the PWM controller and need the output current direction detection, were proposed. This paper presents a novel IGBT gate drive method which is easily implemented within the IGBT gate driver for the PWM voltage source converters. Using this method, the gate drivers of the upper and the lower IGBT´s within a converter phase leg can receive the ideal complimentary (without dead-time) PWM signals, and will not cause the DC link shoot through problem. The gate driver keeps the IGBT off if its anti-parallel diode is conducting current. This novel IGBT gate driver works effectively at low current, low output frequency, and the zero current crossing. In these situations the conventional dead-time compensation often meets problems since the current direction detection will become increasingly difficult, leading to erroneous compensation and waveform distortion. Additionally, the proposed IGBT gate driver is highly cost effective in the low cost, open loop voltage source converters, since no current sensor is required. In this paper, the principle of the proposed IGBT gate drive is described, and the simulation and experimental results validating the proposed method are presented.