DC-DC Converter Capacitor Discharge via Sequential Switching Paths
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Solution Overview
Problem
When external power connection to a DC-DC converter is disconnected, there is a risk of electric shock due to the formation of high voltage in the internal capacitor, as the charge cannot be discharged to the outside, posing a safety hazard.
Innovation Solution
A DC-DC converter with a controller that controls switching elements to provide multiple sequential discharge paths through parallel converting circuits, including inductors and switching elements, to safely discharge the internal capacitor when external power is disconnected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the connector is separated to disconnect external power connection during accident or maintenance, then the risk of electric shock increases due to stored charge in internal capacitor that cannot be discharged, but maintaining connector connection prevents safe discharge path formation
Solution Approach 1:
The patent applies preliminary action by providing a discharge path configuration that is prepared in advance within the DC-DC converter. When external power connection is disconnected, the controller automatically activates pre-configured discharge paths through switching elements to safely discharge the internal capacitor before maintenance or accident response begins, eliminating the need for connector reconnection.
Solution Approach 2:
The patent uses switching elements (MOSFETs or IGBTs) as intermediaries to create controlled discharge paths. These switching elements act as mediators between the internal capacitor and the external environment, allowing safe discharge of stored energy without requiring direct connection to external power sources or ground references.
2Speed
If multiple discharge paths are provided simultaneously, then discharge speed increases, but switching elements may become overloaded
Solution Approach 1:
The patent segments the discharge process into multiple sequential phases, each utilizing a different discharge path. Instead of activating all discharge paths simultaneously, the controller switches between different path configurations in sequence, dividing the total discharge current burden across multiple time intervals and preventing overload of individual switching elements.
Solution Approach 2:
The patent implements periodic action by sequentially activating different discharge paths at different time intervals. The controller periodically switches between various discharge path configurations, allowing each switching element to rest between activation cycles, thereby managing thermal and electrical stress while maintaining effective discharge performance.
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 prevents overload of switching elements and safely discharges the internal capacitor, reducing the risk of electric shock by providing multiple discharge paths that consume the stored charge.
Implementation Method 1
a first capacitor connected to a first DC terminal; a second capacitor connected to a second DC terminal
Implementation Method 2
a plurality of converting circuits each including at least an inductor and a plurality of switching elements
Data Source
AI summary
A DC-DC converter, a vehicle including the converter, and a controlling method thereof are provided. The DC-DC converter includes a first capacitor connected to a first DC terminal, a second capacitor connected to a second DC terminal, a plurality of converting circuits each including at least an inductor and a plurality of switching elements, and connected to each other in parallel between the first capacitor and the second capacitor, and a controller configured to control an ON/OFF state of the plurality of switching elements provided of each of the converting circuits. When external power connection with respect to each of the first DC terminal and the second DC terminal is disconnected, the controller is configured to control states of the plurality of switching elements to sequentially provide a plurality of different discharge paths between opposite terminals of the second capacitor via the plurality of converting circuits.