During　the　operation　of　the　electromagnetic　switches,　the　flux　linkage　can　replace　the　mechanical　parameters　to　characterize　the　motion　of　the　actuator.　But　the　observation　errors　of　the　flux　linkage　will　lead　to　a　failure　of　the　control　strategy.　To　address　this　issue,　a　cascade　control　strategy　based　on　flux　linkage　slope　is　proposed.　The　observed　flux　linkage　is　intercepted　by　a　sliding　window,　the　flux　linkage　slope　is　calculated,　then　the　flux　linkage　slope　is　used　to　establish　a　cascade　control　strategy.　This　strategy　consists　of　an　outer　loop　of　the　flux　linkage　slope　and　an　inner　loop　of　the　coil　current.　The　theoretical　deduction　proves　that　the　flux　linkage　slope　can　be　compatible　with　the　flux　linkage　observation　error　and　reflect　the　change　of　the　real　flux　linkage　caused　by　the　motion　of　the　armature.　The　simulation　results　show　that　the　proposed　cascade　control　strategy　has　good　compatibility　with　the　flux　linkage　observation　error　while　realizing　the　self-adjusting　of　coil　current　with　the　displacement　of　the　armature.　©　Beijing　Paike　Culture　Commu.　Co.,　Ltd.　2025.