Integrating functional safety in motor drives with redundancy and diagnostic coverage

Abstract

Functional safety has become an integral part of motor drives. The main objective of functional safety is to bring the machine to a safe state quickly. A fail-safe system is fault-tolerant and inherently responds in a way that causes no or minimal harm to the machinery and operator. This paper presents the method of implementing safety functions defined in IEC-61800-5-2 like Safe torque off and Safe brake control. It also shows implementation of Safe power supply and Safe digital I/O to be integrated in the power converter for achieving high safety standards. These implementations not only add redundancy but also facilitate diagnostic coverage. The solutions proposed in this paper are validated under different test conditions.