Parasitic Inductance Voltage Sensing for Parallel Power Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In power electronics, parallel-connected power semiconductor devices often experience unequal current distribution due to variations in device characteristics, leading to increased losses and asymmetrical switching operations.
Innovation Solution
A voltage measuring method that measures voltage over parasitic elements, such as stray inductances, in a power circuit, allowing for active control of switching operations to ensure uniform current sharing between parallel power modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage is measured directly across parallel-connected power semiconductor devices, then current distribution can be monitored, but the measurement circuit influences the power circuit and switching operations
Solution Approach 1:
The patent introduces parasitic elements (stray inductances) as intermediary components through which voltage measurements are indirectly obtained. By measuring voltage across these parasitic elements rather than directly across the power semiconductor devices, the measurement circuit does not directly influence the power circuit operation, yet still provides information about current distribution and switching operations
2Power
If parallel-connected power semiconductor devices are used to increase power handling capacity, then power capacity is improved, but unequal current distribution occurs due to characteristic variations
Solution Approach 1:
The patent employs feedback by continuously monitoring voltage across parasitic elements during switching operations and using this information to detect and correct unequal current distribution. The measurement of time-dependent voltage provides feedback about the switching state of each device, enabling active control to equalize current sharing and reduce switching losses
Solution Approach 2:
The patent changes the measurement parameter from static voltage to time-dependent voltage during switching operations. By measuring voltage as a function of time during the switching transient, the system can detect the switching state and use this information to adjust operating parameters and achieve more uniform current distribution
3Ease of operation
If voltage is measured over parasitic elements during switching operations, then current distribution can be controlled, but measurement complexity increases
Solution Approach 1:
The patent utilizes the inherent parasitic elements already present in the power circuit as measurement sensors. These parasitic elements naturally generate measurable voltage signals during normal operation without requiring additional external components. The power circuit's own parasitic characteristics are turned into a self-service measurement mechanism, reducing overall system 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 method enables more uniform current distribution across parallel power modules, reducing switching losses and extending the temperature range of power semiconductor devices.
Implementation Method 1
measuring the voltage over a parasitic element of the power circuit... Preferably, the parasitic element is a stray inductance... a time-dependent voltage is measured during a switching operation
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to the field of power electronics. In order to enable a more uniform current flow through multiple power modules that are coupled in parallel during switching operations, a voltage measuring method for measuring voltage in an electrical power circuit (14) comprising at least one switching element is provided. The voltage measuring method comprises measuring the voltage over a parasitic element (42, L1-L4) of the power circuit (14).