Application of CORDIC Algorithm in Resolver-to-digital and PMSM Vector-control Based on FPGA
Deng Shigang · Micromotors · 2013
In PMSM vector-control,resolver-to-digital needs the arctangent calculations,CLARK-PARK transform needs the sine and cosine calculations,and determining SVPWM sectors and clamp the amplitude of current and voltage vector need to convert the rectangular coordinates into the polar coordinates.All these algorithms are difficult to implement in FPGA with traditional methods.The look-up table often is used in DSP,but it is difficult to meet desired accuracy required frequently.Coordinate rotation digital computer(CORDIC) algorithm is suited to process resolver-to-digital directly and vector-control algorithm in FPGA.Basic theory of CORDIC and application of CORDIC in resolver-to-digital,coordinates convert,SVPWM,and clamp the length of output were discussed in this paper.Operation method and contrast calculation values with real values were provided too.It indicated that the CORDIC algorithm was high accuracy,good performance and low consume of LE.At last,the experiment of PMSM for electric motorcar showed all these algorithms was correct and useful.