The　core　loss　of　magnetic　components　in　power　converter　is　difficult　to　be　quantified　accurately.　To　solve　this　problem,　a　DC　power　measurement　system　is　established　for　pulse　width　modulation　(PWM)　excitation　without　or　with　DC　bias.　Calibration　and　verification　are　implemented　by　using　the　linear　air　core　inductor　whose　loss　can　be　accurately　measured.　The　maximum　relative　error　of　DC　power　measurement　system　by　calorimetry　is　6.59%,　which　can　accurately　measure　the　core　loss　of　PWM　wave　without　or　with　DC　bias.　The　hysteresis　loop　of　PWM　wave　excitation　without　DC　bias　is　analyzed.　The　magnetization　and　demagnetization　of　hysteresis　loops　with　asymmetric　PWM　excitation　are　asymmetric.　A　weighted　average　MSE　model　is　proposed　to　predict　the　core　loss　of　PWM　wave　excitation　without　DC　bias.　The　influences　of　frequency,　duty　cycle,　AC　flux　density　and　DC　flux　density　on　the　core　losses　of　PWM　wave　excitation　with　DC　bias　are　analyzed.　Based　on　the　analysis　results,　a　model　for　the　core　losses　of　PWM　wave　excitation　with　DC　bias　is　proposed.　Experimental　results　show　that　the　maximum　relative　error　of　the　prediction　model　is　-6.9%,　which　has　high　accuracy.　©　2020,　Science　Press.　All　right　reserved.