CHARGED Electric Vehicles Magazine – July-August 2019

CURRENT

SENSORS

28

P

By Jeffrey Jenkins

IN EVS

A CLOSER

LOOK AT

retty much every electronic circuit that

handles significant power utilizes some

means of measuring current, whether to

simply protect against overload or because

it is a basic functional requirement. In this article we’ll

cover some of the more common devices and circuit

techniques for measuring current in the major subsys-

tems of an EV, including when to choose one over the

others.

Current can be sensed or measured in one of two

ways, really: via the voltage drop across a resistor of

some sort, otherwise known as a shunt, or via the

intensity of the magnetic field which radiates from any

current-carrying conductor. In the former case, the

shunt can be an actual resistor made expressly for the

THE TECH