{"title":"Minimization of steady-state torque tracking error in direct-torque controlled PM brushless AC drives","authors":"J. H. Leong, Z. Zhu, J. Liu","doi":"10.1109/EVER.2013.6521612","DOIUrl":null,"url":null,"abstract":"In conventional direct-torque controlled permanent-magnet brushless AC motor drives, the stator flux-linkage and electromagnetic torque are regulated using hysteresis controllers. Unlike the analog counterpart, a digital hysteresis controller operates at fixed sampling period and no control action can be taken between any two sampling instants. Consequently, the controlled variable in a discrete time hysteresis controller may exceed the predefined hysteresis band limits. When the conventional direct torque control scheme is employed, the stator flux-linkage and torque feedbacks are found to exceed the hysteresis band limits. Although the feedback stator flux-linkage goes beyond the band limits, its average tracks the commanded value relatively well. However, due to a significant difference between the rising and falling rates of the feedback electromagnetic torque, a steady-state torque tracking error is resulted. The steady-state torque tracking error can be minimized by employing an improved torque regulator with asymmetric hysteresis band limits.","PeriodicalId":386323,"journal":{"name":"2013 Eighth International Conference and Exhibition on Ecological Vehicles and Renewable Energies (EVER)","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2013-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2013 Eighth International Conference and Exhibition on Ecological Vehicles and Renewable Energies (EVER)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/EVER.2013.6521612","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 1
Abstract
In conventional direct-torque controlled permanent-magnet brushless AC motor drives, the stator flux-linkage and electromagnetic torque are regulated using hysteresis controllers. Unlike the analog counterpart, a digital hysteresis controller operates at fixed sampling period and no control action can be taken between any two sampling instants. Consequently, the controlled variable in a discrete time hysteresis controller may exceed the predefined hysteresis band limits. When the conventional direct torque control scheme is employed, the stator flux-linkage and torque feedbacks are found to exceed the hysteresis band limits. Although the feedback stator flux-linkage goes beyond the band limits, its average tracks the commanded value relatively well. However, due to a significant difference between the rising and falling rates of the feedback electromagnetic torque, a steady-state torque tracking error is resulted. The steady-state torque tracking error can be minimized by employing an improved torque regulator with asymmetric hysteresis band limits.