| Multilevel is a novel technology of power converter since 21stcentury. Multilevel is used in a lot of fields, such as, middle or highvoltage converter and flexible AC transmission system and so on, as afocus of middle or high voltage and space vector pulse widthmodulation(SVPWM) algorithm is studied, which is based on thetopology and mathematical model of multilevel converter. MultilevelAsynchronous motor SVPWM control system is constructed, the systemis simulated and implemented.Multilevel converter is a key of multilevel asynchronous motorSVPWM control system, because it is core of the system. The topology ofmultilevel converter is studied in this paper, such as, NPC converter,flying capacitor converter, cascaded converter and hybrid. Mathematicalmodel is constructed when converter is worked on rectifying state, activeinverting state and passive inverting state. This is a basis for systemimplementation.Multilevel PWM technology is a key of the study of multilevelconverter, because it's affection is important to the output of converter,for example, waveform quality. A lot of modulation algorithm isformulated, for instance, carrier wave modulation and so on.Synchronously, SVPWM technology is introduced at length. Vector timeof operation is calculated, switch sequence is obtained and the problem ofneutral-point potential balancing is discussed as well. Open loop andclosed loop control mode is generalized. A novel SVPWM algorithm isput forward base on geometric idea. The algorithm owes an advantage ofsimplified calculation, performance of system is improved. A novelswitch sequence control technology is put forward. Simulation resultshows that the technology may decrease the fluctuation of neutral-pointpotential.Take these into accounts, multilevel asynchronous motor SVPWMcontrol system is implemented by TMS320F2407A DSP,revolutiondetector,PWM pulse model,IPM and so on. |
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