Adaptive digital drive for high power and voltage IGBT in multi-MW wind power converter

In multi-MW level wind power converter, high current and high voltage IGBT power modules are widely used. And due to the wind power fluctuation, IGBT's power handling ability together with its drive power is fluctuating largely and rapidly. Therefore, the conventional analogy drive circuit has its own limitations such as the parameters in the drive circuit are fixed, which cannot be on-line changed to follow the change of the main circuit's power. In this paper, first, the dynamic characteristics of high power and voltage IGBT are researched; then, the gate drive voltage and gate resistance's influences to driving transients are investigated. According to the research of IGBT's dynamic characteristics, combined with the drawbacks of conventional analog drive method, adaptive digital drive is proposed. In the proposed digital drive, the IGBT's current and voltage are digitally fed back to FPGA; then, the drive circuit's parameters are dynamically changed to implement closed loop di/dt and du/dt control. Hence, adaptive digital drive has a good dynamic response to change of operating conditions.