基于功能安全的旋转变压器解码系统设计

Design of Decoding System for Resolver Based on Functional Safety

针对旋转变压器解码芯片成本高以及常规软件解码系统难以满足高等级功能安全需求的问题,提出了一种无需硬件解码芯片但能符合功能安全需求的解码方案。硬件层面设计了冗余的反馈信号调理电路,分别使用DSADC和常规ADC对正余弦信号进行采样。设计了励磁过流自保护电路和励磁波形监控电路,以降低单点失效和共因失效。将所设计的解码电路制作成电路板进行功能实验,结果表明,该解码系统不仅可以实时准确地输出转子速度,还能满足汽车功能安全需求。

Aiming at the high price of resolver decoding chip and the difficulty of conventional software decoding system to meet the high level functional safety requirements,a decoding scheme which could meet the functional safety requirements without using hardware decoding chip was proposed.A redundant feedback signal conditioning circuit was designed on the hardware,and the signals were sampled by DSADC and VADC respectively.In addition,excitation overcurrent self-protection circuit and excitation waveform monitoring circuit were designed to reduce single point failure and common cause failure.The decoder circuit was made into PCBA for functional experiments.The results show that the decoder system could not only output the rotor speed accurately in real time,but also meet the requirements of automobile functional safety.