The　parallel　hybrid　permanent　magnet　(PM)　magnetic　circuit　used　for　the　constant　and　variable　magnetization　state　application　of　PM　machines,　possesses　the　disadvantages　of　the　severe　cross-coupling　effect　and　complicated　magnetic　pole　structure.　To　deal　with　this　issue,　the　series　hybrid　PM　magnetic　circuit　has　been　presented　to　offer　a　promising　solution.　Based　on　3-D　finite　element　analysis,　the　static　and　dynamic　magnetization　state　analysis　of　the　series　hybrid　PM　magnetic　circuit　in　the　constant　and　variable　magnetization　state　will　be　investigated　in　detail.　A　prototypemagnetization　device　will　be　fabricated　and　corresponding　test　platform　is　built　to　validate　the　theoretical　analysis.　The　analysis　results　confirm　that　the　residual　flux　density　can　well　varies　depending　on　the　applied　external　magnetic　field.