Flexible PCB Discharge Resistor for Vehicle Inverter Safety
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Solution Overview
Problem
Existing power circuit assemblies for vehicles, particularly in inverters for electric machines, face challenges in safely discharging high-voltage energy stores to safe voltage levels below 60 volts, which is hazardous for humans, and require complex and costly discrete resistor components for effective discharge.
Innovation Solution
A power circuit assembly that integrates a discharge resistor as a conductor structure into a flexible printed circuit board, thermally coupled to a heat sink, allowing for efficient thermal management and reduced component complexity by using existing structural elements to convert electrical energy into thermal energy within a predetermined time frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete resistors are used for discharging energy stores, then discharge function is achieved, but device complexity and production costs increase
Solution Approach 1:
The discharge resistor is integrated directly into the flexible printed circuit board as a conductor structure, merging the discharge function with the existing PCB structure. This eliminates the need for separate discrete resistor components and their associated wiring, thereby reducing device complexity while maintaining the discharge function.
Solution Approach 2:
The flexible printed circuit board serves multiple functions: it provides electrical connections between circuit carriers and simultaneously acts as the discharge resistor through its integrated conductor structure. This multi-functionality reduces the number of separate components needed in the system.
2Reliability
If discrete resistors are used for discharging energy stores, then discharge function is achieved, but production time and costs increase
Solution Approach 1:
The discharge resistor is integrated directly into the flexible printed circuit board as a conductor structure, merging the discharge function with the existing PCB structure. This eliminates the need for separate discrete resistor components and their associated wiring, thereby reducing device complexity while maintaining the discharge function.
3Productivity
If high power dissipation is achieved in discharge resistor, then discharge speed improves, but thermal management becomes more difficult
Solution Approach 1:
The heat generated by the discharge resistor, which is normally a harmful byproduct requiring thermal management, is converted into a beneficial feature by using the flexible printed circuit board as a heat sink. The large surface area of the PCB dissipates the heat efficiently, transforming the thermal management challenge into an advantage.
Solution Approach 2:
The flexible printed circuit board serves multiple functions: it provides electrical connections between circuit carriers and simultaneously acts as the discharge resistor through its integrated conductor structure. This multi-functionality reduces the number of separate components needed in the system.
4Reliability
If discrete resistors and wiring are used, then discharge function is achieved, but module size increases
Solution Approach 1:
The discharge resistor is integrated directly into the flexible printed circuit board as a conductor structure, merging the discharge function with the existing PCB structure. This eliminates the need for separate discrete resistor components and their associated wiring, thereby reducing device complexity while maintaining the discharge function.
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 solution enables high power dissipation with minimal space consumption, reduces production time and costs, and enhances reliability by eliminating the need for discrete resistors, while ensuring safe discharge of high-voltage energy stores.
Implementation Method 1
convert the charged electrical energy into thermal energy within a predetermined time period
Implementation Method 2
The flexible printed circuit board is thermally coupled to a heat sink in the region of the at least one conductor structure so that heat from resistor power losses of the at least one conductor structure is transferred directly to the heat sink
Data Source
AI summary
A power circuit assembly for a vehicle. The power circuit assembly includes a first circuit carrier on which at least two power semiconductor switches are arranged; at least one energy store which provides a high voltage and which can be discharged via at least one discharge resistor; a second circuit carrier on which at least two driver circuits are arranged, which are respectively assigned to one of the at least two power semiconductor switches; and a flexible printed circuit board which includes at least one line and electrically connects the first circuit carrier and the second circuit carrier to one another. An inverter including the power circuit assembly for a vehicle is also described.