基于FPGA的整数开方运算

在使用FPGA作为控制芯片对发电机进行控制时,发电机的三相电压有效值计算涉及到开方运算。若要在FPGA上实现某个数的开方运算,QuartusII提供了开方模块altfp_sqrt,但是这个模块有严格的使用要求,要求用户输入的被开方数是IEEE754标准浮点数,altfp_sqrt模块的输出结果也是IEEE754标准浮点数。这种浮点数不便于用户使用和阅读。用VHDL语言提出了一种基于FPGA的整数转换为IEEE754标准浮点数的方法,同时也提出了基于FPGA的IEEE754标准浮点数转化为整数的方法,应用这两种方法再结合Quartus II提供的altfp_sqrt模块实现了对整数的开方运算。以Quartus II为软件工具,以Cyclone II系列的EP2C8Q208C8为硬件平台,在发电机控制应用中对方法的正确性给予了证明。

Operation of Integer Square Root Based on FPGA

When FPGA is used as a control chip in generator control, the operation of three - phase virtual value is necessary, and the operation is referred to operation of square root. When operation of square root is implemented on FPGA, module alffp_sqrt is given by QuartuslI. But this module restricts its input to be IEEE754 standard floating number, and its output to be IEEE754 standard floating number too. It＇ s inconvenient for users to use this module, for they have to change integer to IEEE754 floating number and have to change IEEE754 floating number to integer for the result. Two methods are proposed in VHDL language in this paper. One implements conversions from integer to IEEE754 standard floating ods is proved by being applied in generator control, using Quartus II as software tool and EP2C8Q208C8 of Cyclone II series as hardware platform.