The invention discloses an isolation switch current measurement method based on a double-magnetic-core
alternative energy supply type. The method comprises the steps that the isolation switch current I # corresponding to the
saturation magnetic flux density of a first
magnetic core is set and serves as a threshold value of
magnetic core alternative energy supply; during first-time working, the two magnetic cores operate together, and the test
capacitor is charged through the controllable
rectifier bridge; when the
capacitance reaches a
discharge threshold value, the
microprocessor is started, and the first
magnetic core is set to work firstly (A1 is low and A2 is high); when the
energy management module Vout1 is at a low level, the
capacitor is charged, and the processor records the time and enters a low-power-consumption state; when the
capacitor reaches the
discharge threshold value again, the processor is awakened and records the
current time, and the charging time is calculated; inverting current I1 through a pre-stored current and charging time fitting function, and if I1 is greater than I #, switching a second magnetic core to
supply energy; otherwise, the first magnetic core is still used. According to the invention, the charging time of the test capacitor is measured in a
magnetic field inversion mode to reversely deduce the current of the isolating switch, and the accuracy of measuring the current of the isolating switch can be improved by alternately supplying energy through double magnetic cores.