Multilevel Inverter Current Sensing With One 2D Magnetic Sensor

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Solution Overview

Problem

Existing multilevel inverters in vehicles require multiple current sensors for each phase output, increasing complexity and component count, which is inefficient and costly.

Innovation Solution

Implement a single two-dimensional magnetic field sensor to detect orthogonal magnetic fields from dual output currents in multilevel inverters, reducing the need for multiple current sensors by using a two-dimensional magnetic field detector positioned at strategic locations within the inverter circuit to estimate both output currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple current sensors are used for each phase output in multilevel inverters, then accurate current measurement is achieved, but device complexity and component count increase

Engineering Contradiction:

Improvecurrent measurement accuracyVSAvoidsensor system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple current sensing functions into a single two-dimensional magnetic field sensor. This sensor simultaneously detects orthogonal magnetic field components (Bx and By) that correspond to multiple phase currents, replacing what would traditionally require multiple separate current sensors. The magnetic field sensor integrates multiple measurement capabilities into one device, reducing overall system complexity while maintaining measurement accuracy.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The two-dimensional magnetic field sensor performs multiple measurement functions simultaneously. By positioning the sensor to detect magnetic fields from multiple phases and resolving orthogonal components, a single sensor accomplishes what would traditionally require multiple dedicated current sensors. This multi-functional approach reduces component count while preserving the ability to accurately measure all phase currents.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple current sensors are installed in multilevel inverters, then complete current monitoring is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvecurrent monitoring completenessVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple current sensing functions into a single two-dimensional magnetic field sensor, reducing the total number of components that need to be manufactured and assembled. This consolidation directly lowers manufacturing costs while maintaining complete current monitoring capability through simultaneous detection of orthogonal magnetic field components from multiple phases.

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If a single current sensor is used to detect multiple output currents, then device complexity is reduced, but measurement precision may be compromised

Engineering Contradiction:

Improvesensor system simplicityVSAvoidoutput current estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from one-dimensional current sensing to two-dimensional magnetic field sensing. By measuring orthogonal magnetic field components (Bx and By) in two perpendicular dimensions, the system can simultaneously resolve multiple phase currents from a single sensor position. This dimensional expansion enables the single sensor to capture sufficient information for accurate current estimation without compromising measurement precision.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent replaces traditional contact-based current sensors with a magnetic field-based detection system. This substitution allows non-contact measurement of multiple currents through magnetic field sensing, enabling a single sensor to measure multiple phases simultaneously without the physical constraints and interference issues of traditional current sensors, thereby maintaining accuracy while reducing complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Reduces the number of current sensors required by half, simplifying the system and lowering costs while maintaining accurate current measurement and estimation capabilities.

Implementation Method 1

the current sensor simultaneously detects orthogonal magnetic fields due to current flowing through the first diode and the second diode

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

the multilevel inverter has a full bridge topology connecting a first set of switches to a second set of switches, the first set of switches connected to the second set of switches by a bidirectional switch line

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12447833B2Multilevel inverter current sensing

Publication Date: 2025.10.21 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A conversion system includes a conversion device including a multilevel inverter configured to generate two alternating current (AC) output currents, a current sensor configured to sample a current through the multilevel inverter, or from the multilevel inverter, during a switching cycle, and a processor configure to estimate both of the two AC output currents based on the sampled current from the current sensor.