The design of high performance Rogowski coils

Rogowski coils have become an increasingly popular method of measuring current within power electronics equipment due to their advantages of low insertion loss and reduced size compared to an equivalent current transformer. But there are problems in achieving the essential high bandwidth and high noise immunity required when taking such measurements, particularly on fast IGBT invertor systems. This paper presents a method of achieving a measuring system bandwidth in excess of 20 MHz while maintaining high noise immunity. Part of this advance is within the integrator design but emphasis is also placed on RF design considerations for the coil.