DC-DC Converter Bypass Switches for Lower Conduction Loss
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Solution Overview
Problem
DC-DC converters in battery systems for electric and hybrid vehicles experience conduction loss and potential damage due to continuous operation of power switches, especially when power delivery exceeds system capacity.
Innovation Solution
Incorporating bypass switches that can be selectively controlled to reduce conduction loss by transitioning between different operational modes, such as buck, boost, and bypass modes, using pulse-width modulated signals to manage the switching of power and bypass switches, thereby minimizing the conduction and switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power switches are continuously on to maintain power delivery, then power supply stability is improved, but conduction loss increases
Solution Approach 1:
The patent implements dynamic switching between different operational modes (buck mode, boost mode, and bypass mode) based on real-time system conditions. The bypass switch enables the system to dynamically transition from a high-loss continuous conduction state to a low-loss bypass state when conditions permit, thereby reducing energy loss while maintaining power supply stability through adaptive control.
2Power
If DC/DC converter handles high power delivery, then power output capability is improved, but component damage risk increases
Solution Approach 1:
The bypass switch acts as an intermediary protective element that can rapidly activate to divert excess power away from the DC/DC converter components. When power delivery exceeds safe operating limits, the bypass switch provides a alternative current path, protecting the converter from damage while still allowing the system to handle high power demands.
3Loss of energy
If bypass switches are added to reduce conduction loss, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The bypass switch is designed to serve multiple functions: it reduces conduction loss during normal operation, protects components during high-power events, and enables smooth mode transitions. By consolidating these multiple functions into a single switch element with unified control logic, the patent minimizes the increase in device complexity while achieving significant energy efficiency improvements.
Data Source
AI summary
A power control system includes a battery system and a DC-DC converter with first, second, third, and fourth power switches. A second terminal of the first power switch is connected to a first terminal of the second power switch. A second terminal of the third power switch is connected to a first terminal of the fourth power switch. A first inductor includes a first terminal connected to the second terminal of the first power switch and the first terminal of the second power switch and a second terminal connected to the second terminal of the third power switch and the first terminal of the fourth power switch. A first bypass switch is connected in parallel to the first power switch. A second bypass switch is connected in parallel to the third power switch.