Drive Device Rotation Sensor Noise Reduction
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Solution Overview
Problem
The proximity of the switching elements in the inverter circuit to the rotation sensor in existing drive devices leads to noise interference, affecting the accuracy and performance of the rotation sensor.
Innovation Solution
The rotation sensor is positioned to overlap the motor axis, while the switching elements of the inverter circuit are disposed along the outer peripheral edge of the wiring board, minimizing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the switching element of the inverter circuit is disposed close to the rotation sensor, then the device complexity is reduced, but the rotation sensor is affected by noise generated from the switching element
Solution Approach 1:
The patent applies dimensional separation by arranging components in different spatial zones on the wiring board. The rotation sensor is positioned in a first area while switching elements are placed in a second area, utilizing the planar dimension of the wiring board to achieve physical separation. This spatial distribution reduces electromagnetic noise coupling while maintaining a compact overall device structure.
2Object-affected harmful factors
If the switching element is disposed along the outer peripheral edge of the wiring board, then the noise influence on the rotation sensor is reduced, but the device complexity increases
Solution Approach 1:
The patent segments the wiring board into distinct functional areas: a first area for the rotation sensor and a second area for switching elements. This segmentation allows independent optimization of each zone - the sensor area can be designed for low noise while the peripheral switching area handles power electronics. The wiring board itself acts as a segmented platform that organizes components to minimize interference while maintaining manageable device complexity.
Data Source
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AI summary
A drive device according to the present disclosure includes: a motor including a rotary shaft, a rotor fixed to the rotary shaft, and a winding configured to rotate the rotor around a motor axis by a current flowing through the winding; and a control unit attached to the motor and configured to control a current to be supplied to the winding, in which the control unit includes an inverter circuit including a plurality of switching elements and configured to supply a current to the winding, a rotation sensor configured to determine a rotation angle of the rotary shaft, and a wiring board on which the inverter circuit and the rotation sensor are mounted, and in a planar view, the rotation sensor is disposed in a position overlapping the motor axis and the plurality of switching elements are disposed along an outer peripheral edge of the wiring board.