HEV Converter Asymmetric Phase Layout for Thermal Management
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Solution Overview
Problem
The existing 48V mild hybrid electric vehicle (HEV) converters experience heat concentration and noise issues due to the phase dropping mode (PDM) technology, leading to malfunctions and inefficiencies under low load conditions, as heat and noise are concentrated in adjacent phases.
Innovation Solution
A converter design that disperses heat by strategically arranging metal oxide semiconductor field effect transistors (MOSFETs) and inductors on a printed circuit board (PCB) with a pulse width modulation (PWM) integrated circuit, ensuring that non-adjacent MOSFETs and inductors operate in different phases, thereby minimizing heat concentration and noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phase dropping mode (PDM) technology is used to minimize switching loss and inductor conduction loss, then energy efficiency is improved, but heat concentration and noise occur in adjacent phases leading to malfunctions
Solution Approach 1:
The patent applies asymmetry by intentionally creating non-uniform spacing between adjacent phases on the PCB. Specifically, at least one phase is positioned at a different distance from its adjacent phases, breaking the symmetric arrangement that causes heat concentration. This asymmetric layout allows heat to disperse more evenly across the board while maintaining the energy efficiency benefits of PDM technology.
Solution Approach 2:
The patent implements local quality by varying the spacing characteristics of different phases on the PCB. Each phase can have different spacing distances from its neighbors, creating localized thermal management zones. This allows specific high-heat areas to be spaced further apart while maintaining compact overall design, addressing heat concentration problems locally without sacrificing system-wide energy efficiency.
2Device complexity
If elements operating in four phases are arranged adjacently on the PCB under low load condition, then device complexity is reduced, but heat concentration causes malfunction
Solution Approach 1:
The patent resolves this contradiction by implementing asymmetric spacing where at least one phase is positioned at a non-uniform distance from adjacent phases. This breaks the symmetric pattern that causes heat concentration while still maintaining a relatively simple four-phase configuration, thus preserving low device complexity while improving reliability through better thermal distribution.
Solution Approach 2:
The patent applies preliminary action by pre-planning the asymmetric phase arrangement during the design stage to prevent heat concentration before it occurs. By intentionally positioning phases with varied spacing distances in advance, the design anticipates and prevents thermal problems that would otherwise arise during operation, ensuring reliability without adding operational complexity.
3Productivity
If PWM signals are output to adjacent MOSFETs, then switching operation efficiency is improved, but PWM noise causes malfunction
Solution Approach 1:
The patent addresses PWM noise by implementing asymmetric spatial arrangement of MOSFETs on the PCB. By positioning at least one MOSFET at a non-uniform distance from adjacent MOSFETs, the design reduces electromagnetic interference and noise coupling between switching elements while maintaining efficient switching operation sequences for high productivity.
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 effectively disperses heat and reduces noise interference between phases, enhancing the converter's efficiency and reliability by ensuring that heat is not concentrated in adjacent phases, even under low load conditions, and minimizing malfunctions caused by PWM noise.
Implementation Method 1
a first inductor, which is magnetized according to the switching operation of the first MOSFET to operate in one phase
Data Source
AI summary
Provided is a converter for an HEV system. The converter includes a PCB, a PWM (IC) mounted on the PCB to output a plurality of PWM signals including a first PWM signal and a second PWM signal, a plurality of MOSFETs mounted on the PCB, the plurality of MOSFETs including a first MOSFET, which performs a switching operation according to the first PWM signal, and a second MOSFET which performs a switching operation according to the second PWM signal, and a plurality of inductors including a first inductor, which is magnetized according to the switching operation of the first MOSFET to operate in one phase, and a second inductor which is magnetized according to the switching operation of the second MOSFET to operate in other one phase.