Busbar as current sensor

Patent metadata

Field	Value
Publication number	US-12228591-B2
Application number	US-202017780444-A
Country	US
Kind code	B2
Filing date	Nov 25, 2020
Priority date	Nov 27, 2019
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

A current sensing system includes a pre-calibrated busbar, a voltage sensor, a temperature sensor and a controller. The pre-calibrated busbar has a known resistance, a known variation in resistance with respect to temperature and known dimensions. The voltage sensor detects a difference in voltage between a first location and a second location on the pre-calibrated busbar. The temperature sensor detects an ambient temperature of the pre-calibrated busbar. The controller determines a resistance of the busbar between the first location and the second location based on the known resistance, known variation in resistance, known dimensions and the ambient temperature. The controller additionally determines a current flowing through the pre-calibrated busbar based on the difference in voltage and the determined resistance. The current sensing system has numerous applications including using the determined current to control an operating condition of a solid state circuit breaker or a solid state power controller.

First claim

What is claimed:

1. A solid state circuit breaker system, comprising:
a parallel configuration comprising an electronic switching module connected in parallel with an electronic energy absorbing module, the parallel configuration connected between a voltage source, via a busbar, and a load;
a voltage sensor detecting a difference in voltage between a first location and a second location on the busbar;
a temperature sensor indicating a temperature of the busbar;
a controller determining the current flowing to the parallel configuration based on the difference in voltage and the electrical resistance of the busbar based on the following:

I
=

V
R

 Where:
I=determined current;
V=difference in voltage detected between the first location and the second location;
R=f(r,t,l,A);
Where:
R=electrical resistance of the busbar;
r=electrical resistivity of the busbar material;
t=temperature of first busbar provided by the temperature sensor;
l=length of the first busbar between the first location and the second location;
A=area of the first busbar between the first location and the second location.

2. The system of claim 1 , wherein the over current fault trips a switch in the electronic switching module to open a circuit between the power source and the load.

3. A method of determining an over current fault to activate a solid state circuit breaker, the solid state circuit breaker being coupled between a power supply, via a busbar, and a load, the method comprising:
obtaining a difference in voltage between a first location and a second location on the busbar;
determining a temperature of the busbar;
determining an electrical resistance of the busbar between the first and second locations;
determining a current flowing to the solid state circuit breaker based on the difference in voltage and the electrical resistance of the busbar based on the following;

I
=

V
R

 Where:
I=determined current;
V=difference in voltage detected between the first location and the second location;
R=f(r,t,l,A);
Where:
R=electrical resistance of the busbar;
r=electrical resistivity of the busbar material;
t=temperature of first busbar provided by the temperature sensor;
l=length of the first busbar between the first location and the second location;
A=area of the first busbar between the first location and the second location;

determining that an over current fault has occurred based on the determined current exceeding a rated amperage capacity of the load; and
in response to determining that an over current fault has occurred, tripping a switch in an electronic switching module to open a circuit between the power source and the load.

4. A solid state circuit breaker system, comprising:
a parallel configuration of an electronic switching module connected in parallel with an electronic energy absorbing module, the parallel configuration connected between a voltage source, via a busbar, and a load;
a temperature sensor detecting an ambient temperature of the busbar; and
a voltage sensor detecting a difference in voltage between a first location on the busbar and a second location on the busbar;
a controller determining the current flowing to the parallel configuration based on the following equation:

I
=

V
R

 Where:
I=determined current;
V=difference in voltage detected on busbar;
R=f(r, t, l, A);
Where:
R=electrical resistance of first busbar;
r=electrical resistivity of the first busbar material;
t=temperature of first busbar provided by T 1 ;
l=length of the first busbar between V 1 and V 2 ;
A=area of the first busbar between V 1 and V 2 .

5. A current sensing system, comprising:
a pre-calibrated busbar having a known resistance, a known variation in resistance with respect to temperature and known dimensions;
a voltage sensor detecting a difference in voltage between a first location and a second location on the pre-calibrated busbar;
a temperature sensor detecting an ambient temperature of the pre-calibrated busbar; and
a controller determining:
a resistance of the busbar between the first location and the second location based on the known resistance, known variation in resistance, known dimensions and the ambient temperature;
a current flowing through the pre-calibrated busbar based on the difference in voltage and the determined resistance based on

I
=

V
R

 Where:
I=determined current;
V=difference in voltage detected between the first location and the second location;
R=f(r,t,l,A);
Where:
R=electrical resistance of the busbar;
r=electrical resistivity of the busbar material;
t=temperature of first busbar provided by the temperature sensor;
l=length of the first busbar between the first location and the second location;
A=area of the first busbar between the first location and the second location; and

an electronic switching module configured to open a circuit between a power source and a load in response to determining that an over current fault has occurred based on the determined current flowing through the pre-calibrated busbar.

6. A current sensing method comprising:
obtaining a difference in voltage between a first location and a second location of a pre-calibrated busbar, the pre-calibrated busbar having a known resistance, a known variation in resistance with respect to temperature and known dimensions;
obtaining an ambient temperature of the busbar;
determining a resistance of the busbar between the first location and the second location based on the known resistance, known variation in resistance, known dimensions and the ambient temperature;
determining a current flowing through the pre-calibrated busbar based on the difference in voltage and the determined resistance according to

I
=

V
R

 Where:
I=determined current;
V=difference in voltage detected between the first location and the second location;
R=f(r,t,l,A);
Where:
R=electrical resistance of the busbar;
r=electrical resistivity of the busbar material;
t=temperature of first busbar provided by the temperature sensor;
l=length of the first busbar between the first location and the second location;
A=area of the first busbar between the first location and the second location; and

controlling an operating condition of a solid state circuit breaker or an operating condition of a solid state power controller based on the determined current.

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Baronian Armen
• Singh Yash Veer
• Suntharalingam Piranavan
• Goykhman Mikhail
• Chui Galen

Classifications

• H02M7/003

  Constructional details, e.g. physical layout, assembly, wiring or busbar connections · CPC title

• G01R19/32

  Compensating for temperature change · CPC title

• G01R19/0023

  Measuring currents or voltages from sources with high internal resistance by means of measuring circuits with high input impedance, e.g. OP-amplifiers (electrostatic instruments G01R5/28; measuring electrostatic potential G01R15/165; measuring electrostatic fields G01R29/12; amplifiers per se H03F) · CPC title

• G01R1/203 Primary

  Resistors used for electric measuring, e.g. decade resistors standards, resistors for comparators, series resistors, shunts (resistors in general H01C; microwave or radiowave terminations H01P1/26; coupling devices H01R) · CPC title