Galvanically Isolated DC/DC Converter Switching Control
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Solution Overview
Problem
Previous DC/DC converters experience voltage peaks that are damaging to semiconductor elements due to switching between power transfer states, leading to potential failure or shutdown, which is not effectively managed by existing designs.
Innovation Solution
A galvanically isolated DC/DC converter design that controls switching elements to extend the conductive state of switches beyond the diode's transition from conductive to blocking state, providing a parallel path for discharge currents and reducing voltage peaks, thereby preventing damage to semiconductor components without the need for additional circuit components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If switching elements are controlled to alternate between power transfer states, then power is transferred from first side DC terminals to second side DC terminals, but voltage peaks occur that are damaging to semiconductor elements
Solution Approach 1:
The switch is closed before the diode transitions from conductive to blocking state, preparing a parallel current path in advance. This preliminary action ensures that when the diode stops conducting, the current can seamlessly transition through the switch, preventing voltage peaks that would otherwise damage semiconductor elements.
Solution Approach 2:
The switch acts as an intermediary element that provides an alternative current path. By closing the switch before the diode transitions, it mediates the current flow between the diode and the rest of the circuit, absorbing the current that would otherwise cause damaging voltage peaks when the diode becomes non-conductive.
2Reliability
If additional circuit components are added to protect against voltage peaks, then semiconductor elements are protected, but device complexity and cost increase
Solution Approach 1:
The switch in each parallel circuit serves multiple functions: it enables power transfer during its conductive phase and simultaneously provides voltage peak protection during the diode's transition phase. This multi-functionality eliminates the need for separate protection components, reducing overall device complexity while maintaining semiconductor element reliability.
Solution Approach 2:
The existing switching elements in the parallel circuits serve their primary power transfer function while also providing自我保护 (self-protection) against voltage peaks. By controlling the switch timing to close before the diode transitions, the circuit protects itself without requiring external protection components, thereby reducing device complexity and cost.
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 solution effectively mitigates voltage peaks, reducing the risk of semiconductor damage and eliminating the need for additional components, thus enhancing the reliability and efficiency of the DC/DC converter while maintaining low component count and cost.
Implementation Method 1
a transformer circuit (30), which couples the at least one first side converter circuit (20) to the at least one second side converter circuit (40)
Implementation Method 2
each of the first and second switching elements comprising a switch and a diode connected in parallel
Data Source
AI summary
A galvanically isolated DC/DC converter includes at least one first side converter circuit coupled between a pair of first side DC terminals, and at least one second side converter circuit coupled between a pair of second side DC terminals. The second side converter circuit has at least a first and a second switching element, each including a switch and a diode connected in parallel. When the DC/DC converter is in power transfer operation from the pair of first side DC terminals to the pair of second side DC terminals, the diodes of the first and second switching elements are alternately in a conductive state, with each of the first and second switching elements being controlled such that a closed state of the respective switch extends beyond a transitioning of the diode of the same switching element from the conductive state to a blocking state.