Design Of SPWM Inverter For Asynchronous Motor Based On FPGA

SPWM inverter is a product which is used as a conversion to change DC to AC.And it is widely used in motor drive inverter system,DC power grid inverter system and so on.Design quality of the inverter controller and the main inverter circuit directly determines the performance of the SPWM inverter.Aiming at the disadvantages in existing inverter design schemes,this paper proposed an research idea of using Field Programmable Gate Array hardware devices and Nios ? soft-core processor to design a high-quality SPWM inverter.The main contributions of this paper are as follows:(1)At present,most SPWM inverters use special chips to generate SPWM wave,which lead to some problems such as difficult secondary development,large size and high complexity.Meanwhile FPGA is flexible to use,has fast running speed,rich resources,and can be run in parallel.FPGA was used to produce SPWM wave,which greatly reduced the development cycle time and the difficulty of the development.(2)The core CPU processor of SPWM inverter was designed by using Nios ? soft-core processor,which is supported by most FPGA devices.The core processor of the inverter was realized by combining the hardware design with the software design.Qsys system integration tool was used for the design of hardware part of the processor,and Nios ? IDE integration tool was used for the design of software system.(3)Top-down method was used to design the whole inverter by dividing the inverter into multiple functional modules The inverter was divided into several main modules which includes triangular wave generating module,DDS sine wave generating module,SPWM wave generating module,dead zone module,Nios ? processor module,driving module,filtering module and feedback module.After completing each design of hardware circuits according to the function of each module,each module were finally connected to form the complete system.The modular design scheme greatly reduces the difficulty of design,and the independent function module is conducive to the late maintenance and upgrade.At the end of this paper,a simulation test and a physical test were used to verify the various functions and properties of this FPGA-based SPWM inverter.The experimental results show that the design scheme of the inverter in this paper has simple structure,small size and high integration,basic functions can be completed correctly and effectively.The design scheme of this inverter is feasible.