The invention discloses an
elevator frequency converter IGBT over-temperature
closed loop protection method based on
switching frequency adjustment. The
elevator frequency converter IGBT over-temperature
closed loop protection method comprises the steps that firstly, IGBT junction resistance is detected; secondly, IGBT
junction temperature is worked out; thirdly,
switching frequency is adjusted. According to the
elevator frequency converter IGBT over-temperature
closed loop protection method, the IGBT junction resistance is directly detected, the
junction temperature is accurately worked out for an NPC three-level frequency converter, and the IGBT
internal temperature can be reflected more truly; a temperature closed loop is manufactured, through adjustment of the IGBT
switching frequency, the IGBT temperature of a
rectifier and the IGBT temperature of an
inverter are adjusted independently and dynamically in real time so that the
rectifier and the
inverter can work in a safe temperature range, the frequency converter is controlled to enable the rotation speed of an elevator to be reduced and guarantee
constant torque, and then a
system is in a low-speed stable operation stage; the
junction temperature is displayed visibly, so that operation personnel make judgments and execute corresponding operation conveniently; the real temperature of an IGBT
chip can be accurately detected, and non-shutdown protection can also be conducted.