Electric Power Steering Motor Drive Thermal Management
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Solution Overview
Problem
Existing motor drive control devices for electric power steering experience increased temperature rise due to heat generation from smoothing capacitors and coils, which affects the reliability and compactness of the control board.
Innovation Solution
The motor drive control device design includes a configuration where the smoothing capacitor and coil are positioned away from the control board, with an electrical connection member interposed between them, and a heat sink with varying thickness to absorb and dissipate heat, reducing temperature rise and allowing for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the smoothing capacitor and coil are placed near the control module to achieve a compact design, then the device size is reduced, but the temperature rise in the control module becomes larger due to heat generation
Solution Approach 1:
The device is divided into distinct functional modules: a control module for signal processing and a power module for heat-generating components (smoothing capacitor and coil). This segmentation allows each module to be optimized independently, with the power module positioned away from the control module to dissipate heat effectively while maintaining overall device compactness through modular integration.
Solution Approach 2:
A heat dissipation structure is introduced as an intermediary between the power module and control module. This intermediary component actively manages thermal transfer, preventing heat from the smoothing capacitor and coil from reaching the temperature-sensitive control module, thereby enabling closer placement of components without compromising thermal performance.
2Ease of manufacture
If the smoothing capacitor is placed near the microcomputer to simplify the circuit layout, then the manufacturing process is simplified, but the temperature rise in the control board increases affecting reliability
Solution Approach 1:
The circuit is segmented into a control board containing the microcomputer and a separate power module containing the smoothing capacitor. This segmentation maintains manufacturing simplicity through standardized module interfaces while ensuring reliability by physically isolating the heat-generating capacitor from the temperature-sensitive microcomputer on the control board.
Solution Approach 2:
The smoothing capacitor is extracted from the control board and placed in a separate power module. This extraction removes the primary heat source from the control board environment, thereby protecting the microcomputer and other control components from thermal stress while maintaining ease of manufacture through modular assembly procedures.
3Length of stationary object
If the switching element and control board are placed close together to reduce device height, then the device becomes more compact, but the temperature rise in the control element increases
Solution Approach 1:
The device is segmented vertically into a control module and a power module. The control element resides in the control module while heat-generating components (switching element, smoothing capacitor, coil) are positioned in the power module. This segmentation enables compact vertical integration while maintaining thermal separation through strategic module placement and heat dissipation structures.
Solution Approach 2:
The design transitions from two-dimensional planar layout to three-dimensional vertical stacking with thermal zoning. By utilizing the vertical dimension and creating distinct thermal zones through module separation, the design achieves compact height while preventing thermal coupling between the control element and power components through careful spatial arrangement.
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 configuration effectively suppresses temperature rise on the control board, enhancing reliability and allowing for a lower, more compact motor drive control device by spreading the distance between the control board and heat-generating components, and efficiently dissipating heat.
Implementation Method 1
a heat sink with varying thickness to absorb and dissipate heat, reducing temperature rise
Data Source
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AI summary
A device designed to reduce temperature rise in its control board, and to be compact. The device includes a switching element(4); a coil(9); a smoothing capacitor (10); an electrical connection member(7) for electrically connecting the switching element(9) with the smoothing capacitor (10) and the coil(9); a control board(1) that mounts a control element; a control signal line(5) for electrically connecting the switching element(4) with the control board(1); and a switching element placing portion(6) for placing the switching element (4) thereon. The electrical connection member(7) is arranged between the switching element(4) and the control board(1); the smoothing capacitor(10) and the coil(9) are arranged, with respect to the electrical connection member(7), on a side of the switching element(4); and end surfaces of the smoothing capacitor(10) and the coil(9) are positioned, with respect to the electrical connection member(7), apart from a plane where the switching element(4) and the switching element placing portion(6) are adjoined together.