Rotating Electric Machine Sensor Fusion for Torque Stability
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Solution Overview
Problem
Existing methods for controlling multiphase rotating electrical machines face challenges in accurately determining rotor positions at varying speeds, particularly requiring complex electronics at low speeds and being cost-inefficient at high speeds, leading to torque jumps and noise when switching between sine and block commutation methods.
Innovation Solution
A method using two sensor devices with different resolutions, where the first sensor with higher resolution at low speeds and the second sensor with lower resolution at high speeds, forming weighted average values to maintain accurate rotor position determination without hard switching, thus avoiding torque jumps and noise, and using sinus commutation for all speeds to eliminate method switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution sensor device is used for rotor position detection at low rotor speeds, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the rotor speed range into multiple speed ranges and assigns different sensor devices to different ranges. A first sensor device with high resolution is used for low speed ranges, while a second sensor device with lower resolution is used for high speed ranges. This segmentation allows each sensor to be optimized for its specific operating range, reducing overall system complexity and cost while maintaining measurement precision where needed.
2Measurement precision
If sine commutation is used at low rotor speeds, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic switching between sine commutation and block commutation based on rotor speed. At low speeds where precision is critical, sine commutation is used. At higher speeds where simplicity is more important, block commutation is used. This dynamic adaptation allows the system to maintain control precision when needed while reducing electronic complexity in other operating conditions.
3Device complexity
If block commutation is used at high rotor speeds, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent changes the commutation method parameter based on rotor speed. Block commutation with lower resolution requirements is applied at high speeds where the mechanical system's inherent smoothing effects mask the lower precision, while sine commutation is used at low speeds where precision is critical. This parameter change allows the system to optimize for simplicity at high speeds without sacrificing necessary precision at low speeds.
4Adaptability or versatility
If switching between sine commutation and block commutation is implemented, then adaptability is improved, but stability deteriorates due to torque jumps and noise
Solution Approach 1:
The patent implements smooth transitions between commutation methods by carefully managing the switching criteria and using intermediate transition zones. The switching between sine and block commutation is designed to minimize torque disturbances, and the use of weighted average values for rotor position determination during transitions helps maintain stability while still providing adaptability to different speed ranges.
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 allows for precise rotor position determination across all speeds, reducing the need for costly high-resolution sensors at high speeds and avoiding torque jumps and noise, while maintaining high accuracy and cost-effectiveness.
Implementation Method 1
the first sensor device comprises at least one magnetoresistive sensor or a Hall sensor as an angular position sensor for the acquisition of the first measured values (A) for the rotor positions
Implementation Method 2
the first sensor device comprises at least one magnetoresistive sensor or a Hall sensor as an angular position sensor for the acquisition of the first measured values (A) for the rotor positions
Implementation Method 3
the second sensor device comprises at least three Hall switches with an angular resolution of about 60 degrees for the rotor positions
Data Source
Figure 1~2
AI summary
The invention relates to a method for operating a rotating electrical machine (1) comprising a rotor (3), a polyphase field winding (5) and a commutation apparatus (9) for commutating field winding currents of the field winding (5) depending on rotor position values (R) for rotor positions of the rotor (3). First measurement values (A) for the rotor positions are detected by means of a first sensor apparatus (13) and second measurement values (B) for the rotor positions are detected by means of a second sensor apparatus (15). The rotor position values (R) are formed from weighted average values (M) of the first measurement values (A) and of the second measurement values (B) for the commutation of the field winding currents. The first sensor apparatus (13) has a higher resolution of the rotor positions than the second sensor apparatus (15) in a first rotation speed range of rotor rotation speeds of the rotor (3), and the first measurement values (A) are weighted more heavily than the second measurement values (B) in the first rotation speed range when forming the weighted average values (M).