CURRENT SENSOR

• US 20200132736A1
• Filed: 09/20/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Abandoned Application

• Current Assignee: DENSO Corporation
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: FUJIOKA, Hideaki
• Application Number:
  US16/576,941
• Publication Number:
  US 20200132736A1
• Time in Patent Office: Days
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 19/25 using digital measurement techniques
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 7/003 Constructional details, e.g. physical layout, assembly, wiring or busbar connections
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H02P 29/68 based on the temperature of a drive component or a semiconductor component

Abstract

A current sensor includes a sensor element configured to output a value of physical quantity depending on current supplied to a load; and a sensor controller configured to output a current value based on the output value of the sensor element. The sensor controller is configured to: acquire the output value and a temperature of the sensor element while current is not supplied to the load; determine a correlation between the output value and the temperature based on a plurality of sets of the acquired output value and the acquired temperature; calculate an offset of the output value at a temperature while current is supplied based on the correlation for the temperature of the sensor element; calculate the current value from a value obtained by subtracting the offset from the output value of the sensor element while current is supplied; and output the calculated current value.

Claims

1. A current sensor comprising:

a sensor element configured to output a value of physical quantity depending on current supplied to a load; and

a sensor controller configured to output a current value based on the output value of the sensor element,

wherein the sensor controller is configured to;

acquire the output value and a temperature of the sensor element while current is not supplied to the load;

determine a correlation between the output value and the temperature based on a plurality of sets of the acquired output value and the acquired temperature;

calculate an offset of the output value at a temperature of the sensor element while current is supplied to the load based on the correlation;

calculate the current value from a value obtained by subtracting the offset from the output value of the sensor element while current is supplied to the load; and

output the calculated current value.

2. The current sensor of claim 1, wherein

the current sensor is mounted on a vehicle,

the load is a traction motor, and

the sensor controller is configured to acquire the output value and the temperature of the sensor element under a condition that a gearshift position of the vehicle is in one of P position and N position and a revolution of the traction motor is zero.

3. The current sensor of claim 2, wherein

the current sensor is provided with a power converter configured to convert electric power of a power source to electric driving power of the traction motor,

the vehicle is provided with a temperature sensor configured to measure a temperature of coolant which cools the power converter, and

the sensor controller is configured to estimate the temperature of the sensor element based on current supplied to the fraction motor, a measured value of the temperature sensor, and a voltage in the power converter.