Mixed Critical Resolver-to-Digital Conversion for Safety-Related Servo Drive Applications

Abstract:
A σ-δ ADC-based approach for converting the analog resolver signals into three independent digital position signals – two safety-related and one non-safe – including diagnostics is presented. Comparable to functionally safe encoders for motorintegration, both safe position signals are ready for evaluation by a higher-level safe logic. The almost completely digital signal processing enables a low-cost implementation that efficiently suppresses even high electromagnetic interferences (EMI) from the power stage.