Contactor Position Detection Using Dual Sense Circuits

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Solution Overview

Problem

Existing systems for controlling contactors lack an effective method to determine whether a contactor is in a closed operational position, leading to inefficiencies in opening the contactor.

Innovation Solution

A system utilizing a microcontroller with analog-to-digital converters and output ports to measure low and high side sense signals from sense circuits coupled to the contactor coil, determining if the contactor is closed by comparing signal values to threshold voltages and adjusting control signals accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single sense circuit is used to detect contactor position, then the system complexity is reduced, but the reliability of contactor position detection is insufficient

Engineering Contradiction:

Improvecontactor position detection reliabilityVSAvoidsense circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements different sense circuits at different locations (high side and low side) of the contactor coil, where each circuit measures voltage at its specific location. This local differentiation allows the system to detect contactor position through multiple independent measurements, improving reliability without requiring a single overly complex circuit.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The detection system is segmented into two independent sense circuits: a high side sense circuit measuring voltage near the power source and a low side sense circuit measuring voltage near ground. By dividing the detection function into separate segments, the system achieves more reliable position detection through comparative analysis while keeping each individual circuit relatively simple.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If the microcontroller continuously monitors both high side and low side sense signals, then the diagnostic accuracy is improved, but the processing time and energy consumption increase

Engineering Contradiction:

Improvecontactor position measurement precisionVSAvoidprocessing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The microcontroller is programmed with pre-established threshold values for high side and low side voltage measurements. When a command message to open the contactor is received, the system immediately compares the sense signals against these pre-set thresholds to quickly determine contactor position, avoiding the need for complex real-time calculations and reducing processing time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the microcontroller continuously monitors both sense signals and uses the combined information to accurately determine contactor position. The feedback from both high side and low side measurements allows the system to cross-validate readings and improve measurement precision while using efficient comparison logic to minimize processing time.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10170259B2System for controlling operation of a contactor using a high side sense circuit and a low side sense circuit

Publication Date: 2019.01.01 LG ENERGY SOLUTION LTD

AI summary

A system for controlling operation of a contactor is provided. The system stops outputting a control signal to open the contactor, and then measures a low side sense signal from a low side sense circuit electrically coupled to a low side end of a contactor coil, or a high side sense signal from a high side sense circuit that is electrically coupled to a high side end of the contactor coil, to determine whether the contactor has a closed operational position, and if not, the system stops outputting another control signal to open the contactor.