Inverter Layout With Central Capacitor for Low-Inductance Busbars
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Solution Overview
Problem
Existing inverters in electric vehicles are large, heavy, and generate significant heat and noise due to high electric resistance and magnetic changes in busbars, limiting space and performance in vehicles.
Innovation Solution
The inverter is redesigned with a central smoothing capacitor surrounded by power modules, short busbars with equalized inductance, and silicon carbide MOSFETs to reduce size, weight, and improve cooling and controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the wiring length of the busbar is increased to connect power modules and smoothing capacitor, then the inverter can accommodate more components, but electric resistance increases and copper loss is generated
Solution Approach 1:
The patent transitions from a planar arrangement to a three-dimensional spatial configuration by stacking power modules and the smoothing capacitor in multiple layers. This vertical stacking reduces the horizontal wiring distance while maintaining component capacity, thereby reducing copper loss without compromising the number of components.
Solution Approach 2:
The patent employs a nested arrangement where power modules are positioned around and near the smoothing capacitor in a compact configuration. This nesting minimizes the distance between connected components, reducing busbar length and associated energy losses while accommodating all necessary components within a confined space.
2Ease of manufacture
If the busbar has a complex shape to accommodate component layout, then components can be connected, but magnetic field changes generate noise, vibration, and electromagnetic interference
Solution Approach 1:
The patent employs asymmetric busbar routing that deliberately avoids creating loops, instead using straight-line connections from power modules to the smoothing capacitor. This asymmetric, non-looping path minimizes magnetic field changes and reduces noise, vibration, and electromagnetic interference while maintaining effective component connectivity.
Solution Approach 2:
The patent extracts and eliminates unnecessary busbar loops and complex routing paths that would create magnetic field interference. By taking out only the essential direct connection paths, the design maintains component connectivity while removing sources of electromagnetic interference.
3Loss of energy
If the inverter is disposed near the drive motor to shorten power transmission distance, then efficiency improves, but vehicle body balance and installation space are compromised
Solution Approach 1:
The patent merges the inverter with the drive motor into an integrated electric drive unit. This combination allows the inverter to be positioned immediately adjacent to the motor, minimizing power transmission distance and energy loss, while the integrated unit can be installed in various locations on the vehicle, providing installation flexibility and maintaining vehicle balance.
4Power
If high-voltage power sources are used to increase power output, then driving capability improves, but component sizes and weights increase
Solution Approach 1:
The patent changes the physical parameters of the inverter design by reducing component distances and optimizing spatial arrangement. This allows high-voltage power sources to deliver increased power output without proportionally increasing component sizes and weights, as the compact layout improves efficiency and reduces the mass required for structural support and cooling.
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 achieves a compact, lightweight inverter that enhances vehicle performance by reducing energy loss, noise, and electromagnetic interference, improving fuel and electricity consumption.
Implementation Method 1
Large current also flows through a metal part (busbar), which is an electronic component connecting these components. The metal part is thus also large and heavy. When the wiring length (corresponding to a distance over which current flows) of the busbar increases, electric resistance increases accordingly, and a copper loss is generated during energization.
Implementation Method 2
Moreover, since large current is turned on and off at a high speed by switching control in the inverter, a large change in magnetic field is generated in the busbar accordingly.
Implementation Method 3
a plurality of power modules each of which includes at least one switching element, the plurality of power modules constituting an inverter circuit configured to convert direct-current power into alternating-current power
Data Source
AI summary
An inverter is disposed adjacent to a motor. The inverter includes a plurality of power modules, a smoothing capacitor, and busbars connecting the power modules and the smoothing capacitor. The plurality of power modules are disposed to be arranged along the periphery of the smoothing capacitor. The smoothing capacitor is disposed at a central portion of the inverter and also disposed in the inner portion of the inverter such that the smoothing capacitor and each of the power modules are arranged on the same plane.