High-precision current sensor detecting circuit and detecting method thereof

Abstract

The invention provides a high-precision current sensor detecting circuit which comprises a combined magnetoelectricity conversion unit, a positive threshold comparator, a negative threshold comparator, an OR gate circuit, an output buffer, an analog switch and an ADC (analog-to-digital converter). The combined magnetoelectricity conversion unit comprises a large-range first current sensor and a small-range second current sensor. The output end of the first current sensor is connected to the input end of the ADC through the normally open contact of the analog switch. The output end of the second current sensor is connected to the input end of the ADC through the normally closed contact of the analog switch. The output end of the ADC is connected with the input end of a post-stage circuit. The invention further provides a detecting method of the high-precision current sensor detecting circuit. The high-precision current sensor detecting circuit is wide in measuring range, fast in response, high in measuring precision, good in linearity and dynamic performance, wide in working band, high in reliability, high in overload capacity, and the like.

Description

technical field [0001] The invention relates to the technical field of charging and discharging current detection of electric vehicle power battery systems, in particular to a high-precision current sensor detection circuit and a detection method thereof. Background technique [0002] At present, the isolation detection of the charge and discharge current of the electric vehicle power battery system often adopts the Hall sampling method. The Hall sampling method uses a Hall current sensor for current sampling. The Hall current sensor is based on the magnetic balance Hall principle, that is, the closed-loop principle. The magnetic flux generated by the primary current is concentrated in the magnetic circuit through a high-quality magnetic core. The element is fixed in the air gap to detect the magnetic flux. After processing by a special circuit, the output terminal of the Hall current sensor can output a voltage signal that accurately reflects the change of the primary curre...

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Problems solved by technology

[0003] Therefore, the output linearity of the Hall current sensor is mainly affected by the non-linearity of the magnetic core permeability. When the magnetic field strength increases, its output voltage no longer increases, which affects the measurement accuracy

On the contrary, when the change of the magnetic field is not obvious, the change of the output voltage is relatively small. In this case, when the change of the current is small, the change of the output voltage is not obvious, and it is easy to cause measurement errors.

[0004] In the application process of electric vehicles, when the current flowing through the wire changes by hundreds of amperes, a magnetic core and a Hall element related to the magnetic induction intensity are used, and the output voltage changes linearly, which can reflect the current real current change; When the electric vehicle is in static operation, the main driver has no output, and its operating current varies around ±10-35A. Not obvious, the current output voltage resolution is low, it cannot truly reflect current changes, and there are obvious deviations in SOC statistics, resulting in large current accumulation errors

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