Rotary Transformer Sensor Integration for Brushless Rotor Position Sensing
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Solution Overview
Problem
Traditional wound rotor synchronous machines (WRSMs) face challenges with brushes and slip rings causing friction, wear, and frequent maintenance, while polyphase rotary transformers offer a solution by eliminating these components, but there is a need for a compact and efficient design with integrated rotary position sensors for monitoring rotating members.
Innovation Solution
A rotary transformer system is integrated with a stationary PCB containing an excitation and sensing coils, and a rotating diode holder with targets, allowing for a compact design that includes an inductive position sensor to monitor rotor position efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotary transformer is used to eliminate brushes and slip rings, then reliability is improved, but device complexity increases due to the need for integration with position sensors
Solution Approach 1:
The patent combines the rotary transformer and inductive position sensor into a single integrated assembly. The transformer housing serves as the sensor housing, the primary coil acts as the excitation coil, and the transformer core functions as the sensor target, eliminating the need for separate components and reducing overall system complexity while maintaining reliability improvements from brushless operation
Solution Approach 2:
The patent makes the transformer components serve dual functions: the transformer housing provides both transformer support and sensor housing, the primary coil provides both power transfer and excitation for the position sensor, and the transformer core provides both magnetic coupling and a target for position sensing. This multi-functionality reduces the number of separate components needed
2Volume of moving object
If a compact design with integrated position sensor is implemented, then volume is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent merges the transformer and position sensor into a single compact assembly where components occupy shared space. The transformer housing is the sensor housing, the primary coil is the excitation coil, and the transformer core is the sensor target, achieving volume reduction without requiring additional manufacturing precision beyond what is already needed for the transformer itself
3Ease of manufacture
If traditional separate mounting of position sensor is used, then ease of manufacture is maintained, but device complexity increases and space efficiency decreases
Solution Approach 1:
The patent integrates the position sensor directly into the transformer assembly during manufacturing. The transformer housing serves as the sensor housing, eliminating the need for separate mounting operations. This merging approach actually simplifies manufacturing by reducing the number of assembly steps and components, while simultaneously reducing device complexity
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
The integrated rotary transformer with position sensor provides a compact, efficient, and cost-effective solution for monitoring rotating components, suitable for high-speed applications like electric vehicles, reducing manufacturing costs and improving efficiency.
Implementation Method 1
A stationary printed circuit board (PCB) is provided with the transmitter, sensing coils and position sensor circuitry in the external face of the rotary transformer housing
Implementation Method 2
Polyphase rotary transformers have been utilized in various applications to enable wireless power transfer to the rotor windings of WRSMs
Data Source
AI summary
A rotary transformer is disclosed herein comprising a stationary portion and a rotating portion. The stationary portion includes a transformer housing, a primary coil positioned within the transformer housing and defining a central axis, and a stationary printed circuit board (PCB). The stationary PCB includes an excitation coil of an inductive position sensor and at least one sensing coil of the inductive position sensor. The rotating portion of the rotary transformer includes a rotating PCB with a secondary coil of the rotary transformer positioned on the rotating PCB. The rotating portion further includes a diode holder connected to the rotating PCB. The diode holder includes at least one target for the inductive position sensor.