Application Of Cascaded High Voltage Inverterin Induction Motor Drive System

Nowadays,the energy industry is of great importance to the development of society and economy and the improvement of people’s living standard.In the process of global economic development,the energy shorage not only restricts the economic growth of a large number of developing countriest,but also brings a lot of problems for many developed countries.In China’s electricity consumption,60%of the electricity consumption is consumed by the motor,as one of the major energy consumption of motor in the field of energy saving is a great potential to be tapped.AC variable frequency speed control system has excellent speed regulation performance,significant power saving effect,can greatly improve the utilization of equipment,thereby reducing the power consumption of the motor to achieve efficient operation of the system energy saving purposes.In order to meet the demand of high power AC speed regulation system,the multilevel converter technology with high voltage and high power conversion has become a hot research direction of high power AC speed regulation.Multilevel converters rely on low voltage devices combined traditional high-pressure output,it does not require a step-up transformer,do not use expensivehigh voltage devices,multilevel technology is an excellent structure based on two level converter which is based on the mature topology.Based on the above reasons,this paper focuses on the multi-level inverter type,topology,modulation algorithm,and the application of high voltage inverter AC induction motor speed control system.(1)This paper introduces the application of the multilevel structure,and their advantages and disadvantages are also elaborated,including:diode clamped multilevel inverter,flying capacitor multilevel converter,cascaded H bridge high voltage converter.(2)This paper focused on the H bridge cascaded topology relationship,and introduces the mathematical model of the expression of the output and switch state;from the angle of the multilevel modulation algorithm for cascaded H bridge multilevel converters,and the multilevel PWM algorithm detailed simulation,obtained modulation the algorithm is suitable for cascaded H bridge multilevel converters.(3)The mathematical model of induction motor is derived under the ideal condition,and transformed to the synchronous coordinates to obtain a vector control method for improving dynamic performance of induction motor speed control;According to the mathematical model,a kind of reasoning in order to obtain the speed sensor less control system of induction motor based on Cascaded High voltagehas been verified.(4)Combined with the proposed Cascaded High Voltage Inverter Induction Motor Based on MRAS sensorless control system,an experimental platform is built.The experimental results show that this scheme is feasible in theory and practical engineering.