Research On Electrical Characteristics Measurement Of Polyetheretherketone And Its Impact On Electric Field Distribution In IGBT Submodules

As the key device of a converter valve,the stability of a press-pack IGBT modules is very important.Inside a press-pack IGBT module,there are several submodule installation bases made out of polyetheretherketone(PEEK)and be subjected directly to high voltage.Due to the structural sharp corners of a PEEK frame,partial discharge is likely to occur inside a submodule or between frames,which could jeopardize the insulation performance of a press-pack IGBT module or even lead to breakdown.First,introduction and comparison of different approaches to conductive characteristics are carried out and a test platform aimed at the PEEK conductivity measurement with a wide temperature and field strength range is constructed from the very beginning of designing the device-under-test.After measurement and analysis,the model of the PEEK conductivity to temperature and electric filed strength is obtained.Second,Using the broadband dielectric spectrometer,the frequency domain spectroscopies under different temperatures are analyzed and fitting with extended debye model is carried out.Last,targeted at a press-pack IGBT module currently under development,of which the rating voltage is 3300 V,a 2-D model of submodule and a 3-D model of two-boss submodules are put up,and computer simulations using measurement data of conductivity and permittivity are conducted and hence the field distribution inside the PEEK frame and between two frames.The insulation performance under different temperature is analyzed and of which a practical improving method is brought up.