Active Rotor Rectification for Wireless Motor Power Transfer
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Solution Overview
Problem
Existing electric motor technologies face inefficiencies due to rotor current ripple, which leads to uneven motor operation and power loss, and passive rectification introduces voltage drops and locking states, compromising performance.
Innovation Solution
The implementation of actively rectified rotor windings that capture electrical energy wirelessly from a stator and control current flow, reducing ripple and enhancing torque efficiency through direct stator-rotor coupling for wireless power transfer and control signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive rectification is used for rotor windings, then the structure is simple, but voltage drops and locking states occur compromising performance
Solution Approach 1:
The patent inverts the traditional rectification approach by using active switching devices (MOSFETs/IGBTs) controlled by microcontroller-generated gate signals instead of passive diodes. This active rectification strategy eliminates the voltage drops and locking states inherent in passive rectification, thereby resolving the contradiction between structural simplicity and performance reliability.
Solution Approach 2:
The patent implements dynamic control of rotor current through actively switched rectification, where the microcontroller adjusts switching timing and duration based on motor operating conditions. This dynamic approach allows optimization of torque production and elimination of the static limitations of passive rectification, improving reliability while maintaining manageable complexity through intelligent control.
2Device complexity
If rotor current ripple is present, then the motor operation is simple, but torque generation is uneven and power loss increases
Solution Approach 1:
The patent employs periodic PWM switching signals generated by the microcontroller to control the active rectifier switches. By precisely timing these periodic switching actions, the system smooths rotor current ripple while maintaining simple motor structure, thereby improving torque generation efficiency without excessive complexity.
Solution Approach 2:
The patent implements feedback control where the microcontroller monitors motor operating conditions and adjusts the active rectifier switching accordingly. This feedback mechanism enables real-time optimization of rotor current waveform, reducing ripple and improving torque efficiency while keeping the control system manageable through integrated processing.
3Measurement precision
If wireless power transfer is implemented from stator to rotor, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the stator windings serve multiple functions: they provide both motor operation and wireless power/control signal transfer to the rotor through magnetic coupling. This multi-functionality approach enables precise control signaling without adding separate complex communication systems, resolving the contradiction between control precision and device complexity.
Solution Approach 2:
The patent uses magnetic field coupling through the air gap as an intermediary mechanism for wireless power and control signal transfer. This magnetic coupling acts as a natural mediator that enables precise control signaling to the rotor without requiring physical electrical connections or complex wireless communication hardware, thereby maintaining simplicity while achieving high control precision.
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 approach improves motor efficiency by minimizing torque ripple, reducing power dissipation, and allowing for active control of rotor field polarity, leading to increased torque output and lower core losses.
Implementation Method 1
The rotor is configured to be magnetically coupled to the stator to receive a power transfer signal wirelessly from the stator
Implementation Method 2
The rotor is configured to be magnetically coupled to the stator to receive a power transfer signal wirelessly from the stator
Data Source
AI summary
A stator defines multiple stator poles with associated stator windings. A rotor defines multiple rotor poles with associated rotor windings configured to be energized substantially by the stator. The rotor defines a rotor field energizable by magnetic fields produced by the stator windings to produce relative force between the rotor and the stator. An active rectifier is conductively coupled to one or more first rotor windings. The active rectifier is configured to control a direction of current flow through the one or more first rotor windings responsive to a signal received wirelessly from the stator by one or more second rotor windings.