Modern Ac Drive System Of The Flux Observer And Svpwm Technology Research

Motor is the device that completes the conversion between mechanicalenergy and electrical energy. It can be both power source and the actuator.Nowadays, regardless of production area, or consumption area, motors arenecessary in our daily life. Because of its good performance, DC motorundertakes most of the earliest electricity drives. However, its extensionapplication is limited due to its complex structure, high manufacturing andmaintenance cost and unessential explosion protection. Compared with DC motor,AC motor has simple structure and low production and maintenance cost whichcan be used in bad environment, particular where explosion protection is needed.All its advantages have made AC motor be widely acknowledged and appliedsince it came to the world. What we feel pity for is that the control performanceof AC motor is inferior to DC motor, so DC motor almost controlled the wholemotor market half century ago. The development of AC velocity modulationsystem was accelerated due to the energy crisis, control theory and thedevelopment of high-speed switch component and the microprocessor technology.In today's society, velocity modulation system updates very quickly. AC velocitymodulation system has the potential of taking the place of DC velocitymodulation system. Therefore, enhancing the research of AC velocity modulationsystem and making it have or surpass the high performance that the DC systemhas (width velocity modulation scope, high efficiency, etc.) are certainly a topicthat full of challenge and practical significance.The field oriented control (FOC) and the direct torque control (DTC) arenowadays two mainstream control strategy in Modern AC velocity modulationsystem in which the object is AC motor. Without exception, all of them need touse dynamic motor model, stator or rotor flux estimation and the PWM powersource realized by switching power components. The main content of this paperjust centers on the above three aspects, namely: (ⅰ) establish the dynamicsimulation platform of AC motor; (ⅱ) discuss the flux estimation (observation) indifferent situation; (ⅲ) study the inversion switch algorithm used to realize space vector pulse-width modulation (SVPWM) to guarantee a high voltage use ratio,the least on-off number and symmetry. The conclusion of the project objectresearch needs to be confirmed by test and at least a simulation experiment isneeded. It is also an important part of this paper. Research products have beenseparately published in the "Electrical Machinery Technology", "Proceedings ofChinese control and Decision Conference in 2006", "Proceedings of The 2ndIEEE Conference on Industrial Electronics and Applications (ICIEA 2007, thesource of EI)" and "Small & Special Machines (Chinese core magazine)".The chapters of this Paper are arranged as follows:After outlining the present situation and the development of AC velocitymodulation technology, the second chapter of this paper constructs the simulationmodel of AC motor using modularization method according to its dynamicmathematical model. Base on the work above, we established FOC and DTCsystem simulation platform of AC motor separately and carried on theconfirmation experiment. Based on several main flux observation methods, thethird chapter proposed a novel one which is named mix-switch method anddiscussed the switch issue between different flux observer models. And then,applying mix flux observer model to FOC and DTC systems was carried on. Thefourth chapter of this paper mainly focuses on the SVPWM (space vectorpulse-width modulation) technology and proposed a novel method based on theprinciple and traditional algorithm of SVPWM. And then, we discuss the issue ofapplying SVPWM technology to FOC system. Utilizing the FOC and DTCsimulation platform established in the second chapter, the fifth chapter of thispaper carries on the simulation experiments of applying mix flux model to FOCand DTC system and SVPWM technology to FOC system. All results are givenand simple analysis is carried on in order to confirm the validity of the work wedone before.