DC-bus Voltage Regulation Control Of Permanent Magnet Synchronous Motor Fed By Z-source Inverter

Due to its outstanding characteristics, Permanent Magnet Synchronous Motor(PMSM) has always been a favorable choice in small or medium size electric vehicles(EV). A newly-presented inverter topology, Z-Source inverter, can achieve both voltageboosting and inversion at the same time with an attractive single-stage topology insteadof the conventional two-stage arrangement. Therefore, this novel inverter is quite suitablefor battery or fuel cell electric vehicle applications where wide range operating voltage ofboth dc and ac sides is desired. In the dissertation, an electric propulsion system based onSurface Mounted Permanent Magnet Synchronous fed by Z-Source inverter is presented,with the emphasis on Z-Source network design, the unexpected additional effectsintroduced by sunbber circuit, the load freewheeling path during shoot-through state andthe overall efficiency optimization of the motor/inverter system.The performance of Z-Source is to be affected by the selection of passivecomponents in this unique X-shape Z-Source network. The cause of low-frequencycapacitor voltage and inductor current ripples in single-phase Z-Source network will beanalyzed for the purpose of deriving design guidelines for single-phase Z-Sourcenetwork.A series of new characteristics and problems are introduced by shoot-through state,which should be definitely avoided in conventional topologies, and some of them deservefurther research effort. In this thesis, one unexpected phenomenon brought by twocommonly used sunbber options, namely RCD and C sunbber, will be investigatedthoroughly. Efforts wil be devoted to analyzing the freewheeling path of load currentduring shoot-through and its associated effects on load current ripple and perhaps motortorque ripple.In the electric propulsion system based on Permanent Magnet Synchronous Motorfed by Z-Source inverter, trade-off between voltage boosting and flux weakening has tobe made in order to achieve optimum system efficiency. In the dissertation, various typesof losses, both with the inverter and motor, are calculated theoretically, which paves theway to derive an optimal overall efficiency DC-bus voltage regulation control.