Power Inverter Inductance Reduction via Integrated Capacitor Module
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Solution Overview
Problem
In-car power inverters face challenges in reducing heat generation and size while maintaining high torque demand and efficiency, particularly due to high inductance in existing power inverter designs, which affects heat management and compactness.
Innovation Solution
The power inverter design incorporates a laminated structure with closely placed positive and negative busbars, a capacitor module with laminated busbars, and direct connections between the power module and capacitor module to reduce inductance, along with a coolant passage for efficient cooling, enabling miniaturization and heat reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If inductance is reduced by shortening wiring between the smoothing capacitor and the switching device, then spike voltage is reduced, but the device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The patent combines the smoothing capacitor and busbar into a single integrated capacitor module structure. The capacitor is directly mounted on the busbar, eliminating separate wiring connections and reducing inductance while simplifying the overall device structure and manufacturing process.
Solution Approach 2:
The capacitor is nested within the busbar structure, with the capacitor housing containing the capacitor and the busbar extending from it. This nested arrangement minimizes the distance between components and reduces wiring complexity while maintaining low inductance.
2Object-generated harmful factors
If the number of switching device operations per unit time is reduced to decrease heat generation, then heat generation is reduced, but control accuracy deteriorates
Solution Approach 1:
The patent extracts the heat generation problem from the control system by providing a dedicated cooling system. The cooling device is separately integrated into the inverter structure, allowing the switching device to operate at high frequency for accurate control while the heat is actively removed through cooling passages and heat dissipation structures.
3Volume of moving object
If the power inverter size is reduced to minimize volume, then volume is reduced, but heat dissipation becomes more difficult
Solution Approach 1:
The patent uses three-dimensional cooling passages that extend through the capacitor module and busbar structure. The cooling passages are arranged in multiple dimensions, with some extending in the vertical direction and others in horizontal directions, enabling efficient heat dissipation from the switching device while maintaining a compact overall volume.
Solution Approach 2:
The capacitor module serves as an intermediary heat dissipation structure. The cooling passages are formed within the capacitor module, which acts as a heat sink and thermal conductor. This intermediary structure efficiently transfers heat from the switching device to the cooling fluid while maintaining compact dimensions.
4Object-generated harmful factors
If inductance is reduced by compacting the busbar structure, then inductance is reduced and heat generation decreases, but manufacturing precision requirements increase
Solution Approach 1:
The busbar is pre-formed with integrated cooling passages and mounting structures before final assembly. The capacitor is pre-mounted on the busbar in a controlled manufacturing environment, ensuring precise positioning. This preliminary preparation reduces the precision requirements during final assembly while maintaining the low-inductance compact structure.
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 design effectively reduces inductance and heat generation, enhances cooling efficiency, and miniaturizes the power inverter, increasing the maximum convertible electric power per unit volume while maintaining high performance.
Implementation Method 1
a laminated structure with closely placed positive and negative busbars, a capacitor module with laminated busbars, and direct connections between the power module and capacitor module to reduce inductance
Implementation Method 2
a coolant passage for efficient cooling
Data Source
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AI summary
In a power inverter (200), a coolant passage (19) is fixed to a chassis to cool the chassis (12); the chassis is divided into a first region and a second region by providing the coolant passage in the chassis; a power module (300) is provided in the first region as fixed to the coolant passage; a capacitor module (500) is provided in the second region; and the DC terminal (504; 506) of the capacitor module is directly connected to the DC terminal (314; 316) of the power module.