Impeller Wheel Position Sensing Beyond Back-EMF Saturation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rotating machines and turbochargers face challenges in accurately determining the angular position of the shaft at low and high rotational speeds due to limitations in sensing systems, which are often non-compact, disruptive to airflow, expensive, and prone to inaccuracies from voltage saturation and high acceleration rates.
Innovation Solution
A compact rotating machine design featuring a backplate with a circuit board and sensors to detect target elements on the impeller wheel, allowing for accurate angular position determination without disrupting airflow or requiring expensive sensors, and enabling operation beyond bus saturation levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional position sensors are used to determine angular position, then measurement capability is provided, but the sensors are not compact, disrupt airflow/exhaust flow, and are expensive
Solution Approach 1:
The patent uses target elements (magnetic, reflective, or capacitive markers) attached to the impeller wheel that create detectable signals without requiring complex sensor assemblies. The target elements are simple geometric features that can be detected by relatively simple sensors, effectively copying the function of complex position encoders through simplified marker-sensor interactions.
Solution Approach 2:
The patent extracts the sensing function from the main airflow path by placing sensors on the housing rather than in the exhaust or air streams. The target elements are attached to the rotating impeller while sensors remain stationary on the housing, separating the measurement function from the fluid flow paths.
2Measurement precision
If BEMF sensing is used to determine angular position during electric assembly operation, then sensing capability is provided, but accurate determination is difficult during low and high rotational speeds due to voltage saturation
Solution Approach 1:
The patent introduces target elements as intermediary objects between the impeller wheel and the sensor system. These target elements create distinct magnetic, reflective, or capacitive signatures that provide unambiguous position information independent of the electric assembly's BEMF signals, serving as a reliable mediator for position detection across all speed ranges.
Solution Approach 2:
The patent replaces electrical sensing methods (BEMF-based sensing) with a hybrid approach using physical target elements detected by magnetic, optical, or capacitive sensors. This substitution provides position information that is not dependent on the electrical characteristics of the motor/generator, eliminating the voltage saturation problem inherent in BEMF sensing.
3Productivity
If high current is used to achieve high acceleration rates of the impeller wheel, then productivity is improved, but voltage saturation occurs making angular position sensing increasingly difficult
Solution Approach 1:
The target elements serve as intermediaries that provide position information independent of the electrical system's voltage and current state. The magnetic, reflective, or capacitive targets create detectable signals that are not affected by the voltage saturation caused by high current operation, allowing position sensing to remain accurate during high-acceleration transient conditions.
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
This solution provides a cost-effective, accurate, and compact method to determine the angular position of the impeller wheel across various rotational speeds, enabling precise control and reducing processing power needed for the controller, thus improving the performance and efficiency of rotating machines and turbochargers.
Implementation Method 1
at least one sensor disposed on the circuit board for detecting the at least one target element to determine the angular position of the impeller wheel
Data Source
AI summary
A rotating machine includes a machine housing defining a housing interior, a shaft disposed in the housing interior, with the shaft having a length and an axis extending along the length. The shaft is rotatable about the axis. The rotating machine also includes an impeller wheel disposed in the housing interior and coupled to and rotatable by the shaft, with the impeller wheel having an angular position with respect to the axis. The rotating machine further includes a backplate coupled to the machine housing and having a first side facing the impeller wheel, at least one target element coupled to and rotatable with the impeller wheel, a circuit board coupled to the first side of the backplate and facing the impeller wheel, and at least one sensor disposed on the circuit board for detecting the at least one target element to determine the angular position of the impeller wheel.