An IGBT (insulated-gate bipolar
transistor) stuck-open fault diagnosis method for a three-phase
inverter bridge of a frequency converter belongs to the technical field of IGBT fault diagnosis of three-phase
inverter bridges and solves problem that misdiagnosis is caused in instant load or instant unload when stuck-open fault of IGBTs of an
inverter bridge is determined through the Park
vector method. The method comprises the following steps: firstly,
three phase currents ia, ib and ic of a motor
stator used for speed regulation and controlled by the frequency converter are collected; secondly, the
three phase currents ia, ib and ic are transformed through
discrete Fourier transform to obtain cosine component aj, k and sine component bj, k of
direct current component amplitude and fundamental component amplitude of the
three phase currents ia, ib and ic; thirdly, the
direct current component amplitude is normalized through the fundamental component amplitude to obtain a
direct current component normalization value hj; fourthly, a fault
phrase of the three-phase inverter bridge is determined according to the direct current component normalization value hj; and then whether the faultphrase is in an upper
transistor or a lower
transistor is determined. The invention is suitable for fault diagnosis of three-phase inverter bridges.