Solid-State Bidirectional Relay With Conductor Bar Current Path
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Solution Overview
Problem
Existing solid-state bidirectional relays with back-to-back MOSFETs face challenges in high-current applications due to high resistance and limited current handling capability, especially when using specialized PCBs with heavy copper cladding or copper busses, which are expensive and not scalable for various high-current conditions.
Innovation Solution
A high current solid-state bidirectional relay assembly using MOSFETs aligned in a back-to-back configuration with an intermediate conductor bar, where all current flow is through the conductor bar, eliminating the need for current to pass through the PCB, and utilizing conductive metallic materials like copper, brass, or silver for low resistance paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specialized PCBs with heavy copper cladding or copper busses are used to provide low-resistance path, then current handling capability is improved, but resistance increases and cost increases
Solution Approach 1:
The patent extracts the current-carrying function from the PCB by introducing separate conductor bars. The PCB is removed from the high-current path entirely, with only control signals remaining on the PCB. This separation allows the PCB to be a standard low-cost board while the conductor bars handle all high-current transmission, achieving low resistance without specialized PCB construction.
Solution Approach 2:
The patent segments the electrical connection system into two distinct functional paths: a control path through the PCB and a power path through separate conductor bars. This segmentation allows each component to be optimized for its specific function - the PCB for control signals and the conductor bars for high-current transmission with minimal resistance.
2Reliability
If specialized PCBs with heavy copper cladding are used, then current handling capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the high-current transmission function from the PCB structure entirely. Instead of modifying the PCB with heavy copper cladding or embedded copper busses, the current path is moved to separate conductor bars that connect to the MOSFETs. This eliminates the need for complex PCB construction while maintaining high current handling capability.
3Ease of manufacture
If standard PCBs are used for back-to-back MOSFET connection, then manufacturing simplicity is improved, but current handling capability deteriorates
Solution Approach 1:
The patent segments the electrical system into control and power functions. Standard PCBs are used for control signal routing to the MOSFET gates, while separate conductor bars handle the high-current power path. This segmentation allows use of simple, standard PCB manufacturing processes while achieving high current handling capability through the dedicated conductor bars.
4Reliability
If conductor bars are used instead of PCB for current path, then resistance is reduced and current handling is improved, but PCB control board integration becomes more complex
Solution Approach 1:
The patent extracts the high-current transmission function from the PCB and places it in separate conductor bars. The PCB is reduced to providing only control signals to the MOSFET gates, while the conductor bars with MOSFETs mounted directly form a separate power transmission subsystem. This extraction simplifies the PCB to a standard board while the assembly integration complexity is managed through direct mounting of MOSFETs to the conductor bars.
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 provides a scalable, low-resistance current path capable of handling high currents (greater than 50 amperes) with resistance less than 1 milliohm, eliminating the need for expensive specialized PCBs and enhancing reliability and cost-effectiveness in applications such as battery isolation in vehicles.
Implementation Method 1
provides a low resistance current path for a solid-state bidirectional relay that is separate from the printed circuit control board
Data Source
AI summary
A high current solid-state bidirectional relay assembly includes a first conductor bar, a second conductor bar, and a third intermediate conductor bar. A plurality of MOSFET switching elements are disposed in two back-to-back arrays of switching elements. Either all of the source leads or all of the drain leads of the plurality of MOSFET switching element are electrically connected to the third intermediate conductor bar. The other leads of each MOSFET switching element in one of the arrays are electrically connected to the first conductor bar, and the other leads of each MOSFET switching element in the other array are electrically connected to the second conductor bar. A printed circuit board has control circuitry to control the bidirectional relay. All of the gate leads of the plurality of MOSFET switching elements are electrically connected to the control circuitry of the printed circuit board.