Composite Switching Device Heat Distribution via Periodic Current Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional bridge rectifier circuits experience uneven heat distribution and potential overheating of switches due to imbalanced turn-on times and voltage levels, especially with non-standard AC inputs and DC inputs, leading to inefficiencies and temperature issues.
Innovation Solution
A composite switching circuit is introduced, featuring first semiconductor devices connected in series and second semiconductor devices in parallel, with the latter being turned off during specific periods to transfer current to the former, thereby dispersing heat and reducing switch temperatures. This circuit includes power semiconductor switching devices with body diodes and is applied to bridge rectifier circuits, utilizing MOSFETs, GaN FETs, or SiC MOSFETs, and is thermally coupled to different heat dissipation substrates for enhanced cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If second semiconductor devices are turned on continuously, then current conduction is maintained, but heat concentration and temperature rise occur
Solution Approach 1:
The patent divides the semiconductor devices into two groups: first semiconductor devices (diodes) and second semiconductor devices (switches). By segmenting the current conduction paths and assigning different conduction periods to each group, the heat generation is distributed across multiple devices rather than concentrated in single continuously-conducting switches, thereby solving the temperature control issue.
Solution Approach 2:
The patent implements periodic switching of the second semiconductor devices, turning them on and off in alternating cycles. During the off-period, the first semiconductor devices conduct current; during the on-period, the second semiconductor devices conduct. This periodic action distributes heat generation over time and across different devices, preventing heat concentration and temperature rise.
2Loss of energy
If low turn-on resistance MOSFETs are used, then switching loss is reduced, but device complexity and cost increase
Solution Approach 1:
The patent changes the conduction time parameter of the semiconductor devices. Instead of using low turn-on resistance MOSFETs continuously, the patent allows MOSFETs to conduct only during specific time periods while diodes conduct during other periods. This parameter change (time-based conduction allocation) reduces switching loss without requiring continuously-conducting low-resistance MOSFETs, thereby simplifying the overall device requirements and reducing complexity.
3Power
If all switches conduct simultaneously, then current capacity is maximized, but heat distribution becomes uneven
Solution Approach 1:
The patent segments the total current conduction among different device groups (diodes and MOSFETs) operating in alternating periods. During MOSFET conduction periods, they handle the current; during diode conduction periods, they handle the current. This segmentation ensures that no single group of devices is overloaded, maintaining adequate current capacity while achieving even heat distribution across all devices.
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 reduces the temperature of switches by transferring heat from high-loss second semiconductor devices to first semiconductor devices, improving thermal performance and preventing overheating, while also allowing for the use of devices with higher on-resistance to lower costs.
Implementation Method 1
the second semiconductor device is a power semiconductor switching device having a body diode
Implementation Method 2
at least one of the first semiconductor devices and the at least one second semiconductor device are thermally coupled to different heat dissipation substrates, or thermally coupled to different positions of a same heat dissipation substrate
Data Source
AI summary
The present disclosure discloses a composite switching circuit, including a plurality of first semiconductor devices connected in series; and at least one second semiconductor device each connected in parallel to one of the plurality of first semiconductor devices. The composite switching circuit is connected to an input source. The second semiconductor device is turned off during a preset period to transfer a current flowing through the second semiconductor device to the first semiconductor devices connected in parallel to the second semiconductor device.