Integrated Inverter Bus Bar Bleed Resistor for Safe Capacitor Discharge
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Solution Overview
Problem
Inverters in electrified vehicles face challenges in dissipating residual energy stored in capacitors when the contactor switch is open, as conventional bleed resistors may not effectively manage this energy dissipation and can cause accidental contact between bus bars.
Innovation Solution
The integration of a molded bleed resistor made from polymer or ceramic infused with fine carbon particles, which is bonded directly to the bus bars, provides both energy dissipation and rigid fastening, ensuring safe and efficient energy discharge while maintaining bus bar alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional bleed resistors are used to dissipate residual energy from capacitors, then energy dissipation function is provided, but the bus bars may come into accidental contact and reliability deteriorates
Solution Approach 1:
The patent combines the bleed resistor function with the bus bar support structure into a single integrated component. The molded bleed resistor is positioned between the bus bars and provides both electrical energy dissipation and mechanical separation, eliminating the need for separate components and ensuring bus bars cannot come into contact while maintaining the bleed function.
Solution Approach 2:
The molded bleed resistor performs multiple functions simultaneously: it dissipates residual electrical energy from capacitors through its resistive material, provides mechanical support and positioning for the bus bars, and prevents accidental contact between bus bars through its physical structure. This multi-functional design resolves the contradiction by making the component that provides energy dissipation also the component that ensures safety.
2Loss of energy
If separate bleed resistors are used for energy dissipation, then energy dissipation is achieved, but device complexity increases
Solution Approach 1:
The patent merges the bleed resistor with the bus bar support structure into one integrated component. The molded bleed resistor is positioned between the bus bars and serves both as the energy dissipation element and as the structural support, reducing the total component count and simplifying the overall device architecture while maintaining full functionality.
Solution Approach 2:
The molded bleed resistor is designed to perform multiple functions: electrical energy dissipation through its carbon-loaded material, mechanical support for bus bars, and positional alignment. This multi-functionality eliminates the need for separate bleed resistor components and support structures, thereby reducing device complexity while achieving energy dissipation.
3Loss of energy
If conventional bleed resistors are used, then energy dissipation is provided, but manufacturing and assembly difficulty increases
Solution Approach 1:
The patent combines the bleed resistor and bus bar support into a single molded component that can be manufactured as one piece. This integrated design allows for simplified manufacturing processes and easier assembly, as the component is installed as a single unit rather than requiring separate assembly of multiple components, thereby improving ease of manufacture while providing energy dissipation.
Solution Approach 2:
The molded bleed resistor is designed to perform multiple functions including energy dissipation, mechanical support, and positioning. By integrating these functions into a single component, the patent simplifies the manufacturing process and assembly operations, as the component can be produced and installed as one unit rather than requiring coordination of multiple separate parts.
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 solution ensures safe and efficient dissipation of residual energy from capacitors, preventing accidental contact between bus bars and facilitating assembly, thereby enhancing the reliability and safety of the inverter system.
Implementation Method 1
The molded bleed resistor is configured to dissipate energy from the capacitor
Implementation Method 2
The molded bleed resistor is formed from a polymer or a ceramic and fine carbon particles
Data Source
AI summary
An electric drive system includes a power electronics module with a prefabricated DC bus bar assembly. The prefabricated DC bus bar assembly includes a molded bleed resistor which serves two different functions. First, it dissipates energy from a capacitor when the battery is disconnected. Secondly, it physically supports the positive bus bar and the negative bar with respect to one another.