Integrated Electric Drive Module Cooling for Compact Inverter Packaging
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Solution Overview
Problem
The electrification of vehicle drivelines faces challenges such as high cost, volume constraints, and the robustness of electronics in packaging and space within vehicles, which hinder their widespread adoption over internal combustion engine-powered vehicles.
Innovation Solution
An electric drive module design that includes a housing assembly, electric motor with stator and rotor, and an inverter with power semiconductor devices and heat sinks, featuring liquid cooling and a compact configuration to enhance efficiency and packaging within limited vehicle spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact configuration is used to improve packaging efficiency, then the volume of the electric drive module is reduced, but the cooling efficiency and robustness of electronics may be compromised
Solution Approach 1:
The inverter is nested within the housing assembly of the electric motor, with the circuit board assembly positioned on the first side of the end plate and power semiconductor devices on the second side. This nested configuration allows the inverter components to occupy the radial space within the motor housing, significantly reducing the overall volume of the electric drive module while maintaining proper spacing for cooling and electrical isolation.
Solution Approach 2:
Heat sinks with fins are introduced as intermediary components between the power semiconductor devices and the cooling fluid. The heat sinks receive cooling fluid through inlet ports in the end plate, absorb heat from the power terminals, and dissipate it through the fins into the cooling fluid circulating through the housing assembly. This intermediary heat transfer mechanism enables effective cooling in the compact nested configuration.
2Volume of moving object
If power semiconductor devices are mounted close to the stator windings to save space, then packaging efficiency improves, but thermal management becomes more challenging
Solution Approach 1:
The heat sinks are positioned locally adjacent to the stator windings with their fins extending into the annular region where cooling fluid flows. This local placement of heat dissipation components ensures that thermal management is optimized at the specific location where heat is generated by the power semiconductor devices, allowing compact packaging while maintaining effective cooling through the cooling passages in the stator.
3Volume of moving object
If the inverter components are integrated within the motor housing, then the overall module volume is reduced, but the complexity of assembly and manufacturing increases
Solution Approach 1:
The inverter is segmented into distinct modular components: the circuit board assembly with control electronics on the first side of the end plate, and the power semiconductor devices mounted on heat sinks on the second side. The retaining member is separately formed to hold these components. This segmentation allows each component to be manufactured and tested independently before final assembly within the motor housing, reducing overall manufacturing complexity despite the integrated configuration.
Solution Approach 2:
The end plate serves multiple functions: it provides structural closure for the housing assembly, supports the circuit board assembly on its first side, supports the power semiconductor devices and heat sinks on its second side, and contains inlet ports for cooling fluid distribution. This multi-functionality reduces the number of separate components needed, simplifying the overall assembly process while achieving compact integration.
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
The design improves the packaging efficiency, cooling, and robustness of electric drive modules, addressing cost and space constraints while maintaining performance, thus facilitating the transition to electrified vehicle drivelines.
Implementation Method 1
The power terminal of each of the power semiconductor devices is mounted to the one or more heat sinks
Implementation Method 2
The fins of the heat sinks are disposed in an annular region that is adjacent to the axial ends of the sets of field windings. The annular region is in fluid communication with the stator cooling passages
Implementation Method 3
An inlet port is formed through the end plate. The inlet port is adapted to receive a liquid cooling fluid therethrough. The inlet port is coupled in fluid communication to the annular region
Implementation Method 4
The annular region is in fluid communication with the stator cooling passages
Data Source
AI summary
An electric drive unit having a stator, a rotor received in the stator and rotatable about a central longitudinal axis, and an inverter assembly that includes a plurality of power semiconductors, a plurality of heat sinks and an end plate. The power semiconductors are thermally coupled to the heat sinks. Each of the heat sinks has a plurality of fins that extend into a flow channel that is coaxial with the plurality of sets of field windings. The end plate is coupled to the power semiconductors and has a projection, which is sealingly coupled to the stator and which and partly defines an annular cavity, and a coolant port that is coupled in fluid communication with the annular cavity. The flow channel is in fluid communication with and disposed in a flow path between the annular cavity and the cooling channels in the stator body.