The Research And Realization On PWM Converter Of Permanent Magnet Synchronous Generator

The energy provides a powerful drinving force for the technology advance,rapid economic growth,continuous improvement of people's living standard and great wealth of material and spiritual civilization.The electric energy is so clean,convenient,efficient and controllable that leads other energy to converting to it.As the Organic Rankine Cycle become the main way of collection and convertion of the low temperature heat source,high efficient expansion turbine is used as the tool converting the internal energy to mechanical energy.The high-speed and high-efficiency PMSG(Permanent Magnet Sysnchronous Generator)becomes the inevitable choice the converts from mechanical energy to electic energy because of the feature of the expansion turbine.Moreover,the high-speed PMSG is also applicable to high-speed gas turbine power generation.The paper mainly researchs a high-speed permanent magnet synchronous grid power generation,which is not only applicable for low temperature waste heat,geothermal and solar thermal power generation,but also for gas turbine power generation.The increasement of the PMSG working speed leads the AC power frequency of the generator output to being high accordingly,so that could no be connected to the grid.So the AC-DC-AC converter is of importance for the power utilization.The PWM converter used in motor side could play an important role in reduction of the low order current harmonic,efficiency improvement of the generator and real-time adjustment of the output power.Therefore,the paper mainly researched the high speed PMSG PWM converter based on the project development experience of the 350kW high-speed permanent magnet synchronous grid power generation system.The main contents are as follows:Firstly,the paper proposed the direct-drive permanent magnet topplogical structure.And further analysis has been carried on the motor side PWM converter.Then,The PMSG and PWM converter model have been built,and rotor flux oriented,the voltage and current double-loop vector control strategy of the motor side PWM converter has been proposed.And the design of the PI(proportion integration)controller parameter in the double-loop vector control strategy has been introduced in it.Moreover,the simulation and experience results of the 400kW PMSG PWM converter verified the strategy is correct.Secondly,the mothod of improving the current waveform has been propose by increasing the stator inductance for the problems of small inductance of the generator,poor current waveform,rotor fever.The flux-weakening contol strategy based on the d-axis voltage loop has been proposed to weaken cross-axis armature reaction for the interior permanent magnet generator(IPMSG)PWM converter after the increasement of the inductance and high output voltage.The simulaton analysis of PWM converter control in rated state and the dynamic process of speed mutation and load changing,which verified the method is correct and applicable.Finally,the problem of the output power for high-speed permanent magnet synchronous grid power generation in the case of open-loop thermal conversion system has been solved.According to the control strategy of the motor side converter,two power tracking control methods have been proposed on the basis of the basic theory analysis of the thermal con-version system.And the control theory and the advantages and disadvantages have been analyzed in this paper.At last,the paper simulated the speed and current double-loop control method and the process of geothermal power system,which proved the strategy is corrent.Furthermore,the last two power tracking control method and no shock grid integration in the motor side has been analysed and verified by experience.