基于查找表和Newton插值算法的正余弦函数的FPGA实现

Implementation of sin&cos function on FPGA based on look-up table and Newton algorithm of interpolation

正余弦函数在任意次谐波电流的无锁相环ip-iq检测法中有着重要应用。提出了一种基于查找表和Newton插值算法相结合的正余弦函数的实现方法,给出了具体计算公式和RTL级方框图;与查表法和CODIC算法相比,该方法所需时钟周期少(只需120个时钟周期),精度高(可达±1LSB),占用资源少(只需483个LE单元)。在Altera公司的Cyclone系列FPGA器件EP1C6Q240C8上完成了硬件验证,最终应用到某谐波检测ASIC设计中。

Sin＆cos function has important application in method for random harmonic current detection of ip-iq transformation without phase lock loop.A method is proposed for implementing sin＆cos function based on look-up table and NEWTON algorithm of interpolation, and the equation and the RTL frame are given.In contrast with other method ,this method is less clk time（only need 120 clk） and high precision （±1LSB） and less resource consumption （only need 483LE） . This paper implements the hardware on the cyclone II device of altera corporation, finally, it is applied into the design of ASIC for harmonic detection.