IGBT Modules - Technologies, Driver and Application (Second Edition) - page 449

12M
437
When using Hall sensors, there are a number of sources of error to be borne in mind,
whichmust be compensated for by appropriatemeasures. Typical sources of error are:
Shape
The influence of imprecisemanufacturing, such as the positioning of the sense
contacts.
Thermoelectriceffect
The influence of regions of varying temperature in the Hall sensor, caused by
internal or external sources of heat. There is also the influence of the Seebeck
effect
23
T
U
Sb
∆⋅α=
between the contacts.
Mechanical strain
The action of other influences on the Hall sensors, e.g. mounting, package,
etc. that lead tomechanical strain on the component.
Self-induction
The influence of the magnetic field that is induced via the leads of the Hall
sensor.
Tominimise the above sources of error to the greatest extent possible, Hall sensors are
offered in complex, integrated solid-state circuitswith compensation functions.
Fig. 12.21
Hall sensor
Hall sensors can also be used to directlymeasuremagnetic fieldswhich are shown by a
proportionateHall voltageU
H
. Indirectly, Hall sensors can also be used for potential-free
measurement of current. Typical applications fall intooneof two categories:
Open loop converters
Closed loop converters
23
Electric voltage that can occur between two points that show different temperatures on an electrical conductor
is named after German physicist Thomas Seebeck (1770 - 1831).
T is the difference in temperature between
the points being observed and
α
the Seebeck coefficient or the thermoelectric force a material constant
represents.
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