在降本增效要求的推动下,智能电表的电机控制单元(MCU)逐渐采用片上系统(SoC)方案,在集成电子技术发展基础上趋向多元件集成.针对目前应用的大多数SoC芯片内置实时时钟(RTC)模块需要时钟补偿才能满足国网±0.5 s/d精度要求的问题,提出了通过硬件温度检测和在软件上采用最小二乘法曲线拟合晶体振荡器温度特性对RTC进行温度补偿的方案,结合Matlab最小二乘法曲线拟合工具进行数据分析与研究,并采用三次曲线拟合补偿曲线,经测试验证可达到在-45～ +75℃的温度范围内±0.5 s/d的系统精度要求.该方法已通过批量验证,完全能满足国家电网新一代智能电表的时钟精度要求,为智能电表等自动化仪表的RTC方案选择提供了新思路和新方向.%Driven by the requirements of the cost reduction and higher efficiency,the System-on-a-Chip (SoC) scheme has been adopted gradually for MCU of the smart meters,and on the basis of the development of integrated electronic technology,the multi-component integration is the trend.At present,most of the built-in real time clock (RTC) modules of SoC need clock compensation for meeting the accuracy requirement of ± 0.5 s/d for the State Grid;aiming at this issue,the strategy of temperature compensation for RTC is proposed;with this strategy,temperature is detected by using hardware,and the least square curve fitting for temperature characteristics of the crystal oscillator is used in software.Combining with Matlab least squares curve fitting tool,data analysis and research are conducted,by using cubic curve fitting compensation curve,and by test and verification that this method can reach the demand of ± 5 s/d system accuracy between temperature-45 ～ + 75 ℃.Batch verification of this method has been passed;the accuracy of the clock in new generation of smart meters can be fully satisfied,which provides a new concept and direction in selecting RTC scheme for smart meters and other automation instruments.
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