Rotation Angle Estimation Noise Reduction via Vector Cancellation
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Solution Overview
Problem
Existing rotation angle estimation apparatuses for rotating electric machines face challenges in reducing noise generated by high-frequency voltages without compromising estimation accuracy, as previous techniques either fail to sufficiently reduce noise or sacrifice accuracy.
Innovation Solution
The apparatus sets high-frequency voltages with consideration for the spatial phase difference between winding groups, ensuring the magnitude of the resultant vector of high-frequency voltage vectors is smaller than individual vectors in a fixed coordinate system, allowing for noise reduction without sacrificing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency voltages are applied for rotation angle estimation, then rotation angle estimation accuracy is improved, but noise is generated
Solution Approach 1:
The patent converts the harmful noise generated by high-frequency voltage application into a beneficial effect by carefully controlling the phase relationships. By setting the high-frequency voltages such that their resultant vector magnitude is smaller than individual vector magnitudes, the noise is reduced while maintaining the estimation functionality. This transforms the harmful noise into a controllable parameter that can be optimized.
Solution Approach 2:
The patent changes the phase parameters of the high-frequency voltages applied to different winding groups. Specifically, it controls the phase differences between voltages applied to first and second winding groups, ensuring that the resultant vector magnitude is reduced. This parameter optimization allows simultaneous achievement of noise reduction and accurate rotation angle estimation.
2Object-generated harmful factors
If known noise reduction techniques are used (increasing frequency separation, lowering frequencies, or lowering amplitudes), then noise is reduced, but rotation angle estimation accuracy is sacrificed
Solution Approach 1:
The patent applies dynamic phase control to the high-frequency voltages. By continuously adjusting the phase relationships between voltages applied to different winding groups based on the spatial phase differences, the system dynamically optimizes the resultant vector magnitude. This dynamic control enables noise reduction without sacrificing estimation accuracy, overcoming the limitations of static approaches.
Solution Approach 2:
The patent segments the high-frequency voltage application into multiple independent winding groups (first and second winding groups with different spatial phase differences). By controlling each winding group's voltage phase independently and optimizing their combined effect, the system achieves noise reduction while maintaining sufficient signal strength for accurate estimation. This segmentation allows fine-grained control over the noise-estimation tradeoff.
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 effectively reduces noise generated by high-frequency voltages while maintaining the accuracy of rotation angle estimation, unlike previous methods which either failed to reduce noise or compromised accuracy.
Implementation Method 1
a rotation angle estimating unit that estimates a rotation angle of the rotating electric machine based on at least one of high-frequency currents that flow in the winding groups upon application of the high-frequency voltages to the winding groups
Data Source
AI summary
A rotation angle estimation apparatus includes: a high-frequency voltage setting unit that sets high-frequency voltages; a circuit operating unit that operates an electric power conversion circuit to apply each of the high-frequency voltages to a corresponding one of winding groups of a rotating electric machine; and a rotation angle estimating unit that estimates a rotation angle of the rotating electric machine based on at least one of high-frequency currents that flow in the winding groups upon application of the high-frequency voltages to the winding groups. Moreover, the high-frequency voltage setting unit sets the high-frequency voltages based on the spatial phase difference between the winding groups so that in a fixed coordinate system of the rotating electric machine, the magnitude of a resultant vector of a plurality of high-frequency voltage vectors, which are respectively applied to the winding groups, becomes smaller than the magnitude of each of the high-frequency voltage vectors.