Wide bandwidth and low propagation time delay current sensor applied to a laminated bus bar

DC-side currents in an inverter circuit, which is used for a motor drive or an over-current protection circuit, is pulse string, so the frequency components of the DC-side current has DC to hundred kHz. In addition, almost of the current sensors can be applied to a wire, but it is difficult to detect the bus bar current. Therefore, it is important to consider both electric characteristics and a structure of the current sensors. Many papers focused on current sensors deal with only electric characteristics, so have never been discussed an arbitrary structure current sensor for a laminated bus bar. This paper proposes a current sensor applied to a laminated bus bar. The current sensor consists of the parallel connected chip resistors, so the arbitrary wiring structure such as a laminated bus bar can be applied. The proposed current sensor is applied to an over-current protection circuit, and it will be confirmed the validity of the proposed circuit by the 250-V, 20-A buck chopper circuit.