Converter Module Switching Loss Reduction via Parasitic Inductance Management
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Solution Overview
Problem
Switching regulators face significant switching losses due to turn-ON and turn-OFF losses, primarily influenced by parasitic inductance and reverse recovery losses, which affect the efficiency of power conversion in DC/DC and DC/AC converters.
Innovation Solution
The implementation of a series circuit to temporarily store energy induced by parasitic inductance and an active circuit to control the release of this energy, along with inductive decoupling of switching stages and strategic grouping of components on different power substrates to minimize inductive coupling, reduces switching losses and improves efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If switching elements are used to convert DC input voltage to DC or AC output voltage, then power conversion function is achieved, but switching losses occur due to turn-ON and turn-OFF losses
Solution Approach 1:
A parasitic inductance is intentionally introduced as an intermediary element in the circuit. This parasitic inductance acts as a mediator that temporarily stores energy during switching transitions, reducing the direct impact of turn-ON and turn-OFF losses on the switching elements. The parasitic inductance absorbs the harmful switching transients and releases them in a controlled manner, thereby improving power conversion efficiency by reducing switching losses.
Solution Approach 2:
The invention converts the harmful effect of parasitic inductance, which typically causes voltage spikes and oscillations during switching, into a beneficial effect. By deliberately utilizing the parasitic inductance to store energy during switching transitions, the circuit transforms what would normally be a source of loss and instability into a mechanism that reduces switching losses and improves overall efficiency.
2Device complexity
If switching elements are grouped on the same power substrate, then device complexity is reduced, but inductive coupling between stages increases causing cross-conduction losses
Solution Approach 1:
The invention segments the power substrate into multiple isolated regions or layers, each housing specific switching elements or circuit stages. This segmentation physically separates the switching elements to minimize parasitic inductive coupling between stages while maintaining low parasitic inductance within each segment. The segmented structure allows for independent optimization of each region, reducing cross-conduction losses while managing device complexity.
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 approach effectively reduces switching losses by managing parasitic inductance effects, enhancing the overall efficiency of switching regulators and reducing cross-conduction losses in multi-stage converters.
Implementation Method 1
Switching losses of switching regulators do not only depend on the built-in parameters and the control of the switching regulator but are also influenced by the surrounding circuit design. Parasitic inductances, for instance, which are present in every power electronic circuit, also affect the switching losses of a regulator.
Implementation Method 2
For this purpose, a controller controls switching element 1304 to change between a conducting and a non-conducting state. When switching ON switching element 1304, current flows from input terminal 1301 to output terminal 1303
Implementation Method 3
In case of an inductive load, as indicated in FIG. 13 by inductor Lload, when switching OFF of the switching element 1304 a current is induced by the inductor Lload which may circle between diode 1305, Rload and Lload. The induced current is often referred to as freewheeling current
Data Source
AI summary
The invention relates to converters for converting a DC input voltage a DC or an AC output voltage. The converters have a parasitic inductance. The converters comprise at least one switching element connected to an input terminal for providing a first voltage at an output terminal. In order to allow temporarily storing, in a capacitor, energy induced by the parasitic inductance when switching OFF the switching element, a first series circuit of a diode and a capacitor is provided in the converter, wherein the diode is coupled to the one input terminal. An active circuit coupled in parallel with the diode enables controlling the release of temporarily stored energy from the capacitor of the first series circuit.