A high voltage fluid heater (HVCH)
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Solution Overview
Problem
Conventional high voltage fluid heaters (HVCHs) face packaging issues due to the stacking of components along one direction, limited creepage distance between high voltage PCB portions and bolt heads, and the need to bend lead frames, which increases assembly time and spacing between power transistors.
Innovation Solution
The HVCH design includes a housing with components arranged such that the power transistor assembly, thermal pad, and spring element are disposed along a side wall at an angle to the PCB, preventing stacking and ensuring sufficient creepage distance. Lead frames are orthogonally connected to the PCB, eliminating the need for bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If components (power transistor assembly, thermal pad, spring element) are stacked along one direction in conventional HVCH, then the height is reduced, but packaging issues arise and creepage distance is limited
Solution Approach 1:
The patent redistributes components from a vertical stacking arrangement to a horizontal distribution along the housing perimeter. The power transistor assembly, thermal pad, and spring element are positioned along a side wall at an angle to the PCB, utilizing the horizontal plane rather than stacking vertically. This dimensional change increases creepage distance while maintaining compact overall dimensions.
2Ease of manufacture
If lead frames are bent to connect power transistors to PCB, then connection is achieved, but assembly time increases and spacing between power transistors increases
Solution Approach 1:
The lead frames are pre-configured in a straight configuration during power transistor assembly, eliminating the need for bending operations during final assembly. The power transistors are positioned and connected to the PCB using straight lead frames that extend directly from the transistor bodies, removing the bending step entirely and reducing assembly complexity.
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 addresses packaging issues by maintaining a compact height, enhances creepage distance to prevent short-circuits, and simplifies the assembly process by eliminating lead frame bending, thereby improving the overall performance and reliability of the HVCH.
Implementation Method 1
The power transistors 3b are cooled by the fluid circulating across the conventional high voltage fluid heater 1
Implementation Method 2
The thermal pad 4 disposed between the power transistor 3b and the corresponding flat platform portion 1b further enhances the surface contact between the power transistor 3b and the flat platform portion 1b, thereby resulting in improved cooling of the power transistor through the fluid circulating in the conventional HVCH and improved heat dissipation from the power transistors 3b
Data Source
AI summary
A high voltage fluid heater includes a housing that includes at least one of walls and openings along different sides of the housing to define at least one enclosure. The housing also includes an inlet and an outlet for fluid to flow into and out of the housing. The heater also includes a printed circuit board along a first plane along one side of the housing, a heating element controlled by the printed circuit board, a power transistor assembly including a plurality of power transistors, at least one thermal pad along a side wall of the housing, and at least one spring element. Each power transistor includes a plurality of lead frames emanating from the transistor and adapted to be connected to the printed circuit board. The fluid heater also includes a spring element adapted to be mounted on the housing.