A novel insulation space charge non-contact measurement method based on elasto-optical sensing and ellipsometric detection

To clarify the insulation charge accumulation mechanism under complex PWM (Pulse width modulation) stress condition, a novel insulation space charge non-contact measurement method based on elasto-optical sensing and ellipsometric detection is proposed. Then, polymorphic signal propagation model between electrical pulse, space charge, elastic wave and optical probe signal is constructed. Meanwhile, the charge measurement feasibility is evaluated experimentally by comparing with traditional PEA (Pulsed Electro-Acoustic) charge detection system. It is shown that the charge ellipsometric detection system could achieve the charge measurement without averaging. In addition, the spatial resolution of the ellipsometric detection system could be about 15 mu m, which is consistent with the traditional PEA detection system. The related work could provide a reliable technical means to achieve dynamic tracking of insulation charge evolution under complex stress, supporting the optimization design of the power electronic equipment insulation system.