Laminated busbar design and stray parameter analysis of three-level converter based on HVIGBT series connection

Multilevel technology and power semiconductor devices in series connection can both effectively improve the converter system power capacity. But both of them will enlarge the system size and lead to complex busbar structure which may cause large stray parameters, especially the stray inductances. Large stray inductance has a critical effect during the device transient process and may cause device damage and failure. Therefore, the laminated busbar structure is widely used in high power converters to decrease the wiring stray inductances. In this paper, based on the current commutation loop (CCL) analysis of a 3-level high-voltage insulated gate bipolar transistor (HVIGBT) series bridge, the structure design method of the 3-level HVIGBT series connection test platform is described. The influence of the laminated busbar to the adjacent busbar is analyzed and the improved stray parameter calculation method is proposed. The experimental results verify the validity of the structure design method and the veracity of the stray parameter calculation method.