Rogowski Coil Current Sensing for Fast Power Converter Protection
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Solution Overview
Problem
Current sensors for power electronic converters are costly, large, and have slow response times with significant losses, making them inefficient for protection and control purposes.
Innovation Solution
A system utilizing high-bandwidth Rogowski coils and a digital signal processor (DSP) to measure and reconstruct drive current signals from power switching circuits, enabling fast and accurate current sensing by integrating Rogowski coils directly into the switching circuit, eliminating the need for magnetic cores and current-sense resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional current sensors are used for power electronic converters, then current sensing function is provided, but the sensors are costly, large, and have slow response times with significant losses
Solution Approach 1:
The patent segments the current sensing function into two separate high-bandwidth sensors that measure high-side and low-side current pulses independently. This segmentation allows each sensor to be optimized for specific switching conditions, achieving faster response times and reduced losses compared to a single traditional sensor
Solution Approach 2:
The patent replaces traditional magnetic core-based current sensors with Rogowski coils that have no magnetic core. This substitution eliminates the mechanical/physical constraints of magnetic saturation and core losses, enabling high-bandwidth operation with minimal energy losses and significantly faster response times
2Reliability
If traditional current sensors are used for power electronic converters, then current sensing function is provided, but the sensors are costly and large
Solution Approach 1:
The patent merges the current sensing function directly into the power switching circuit by integrating Rogowski coils at the switch nodes. This integration eliminates the need for separate traditional current sensor assemblies, reducing overall device complexity while maintaining high reliability for protection and control functions
Solution Approach 2:
The patent creates a digital copy of the current waveform by sampling high-side and low-side pulses and reconstructing the complete drive current signal in the digital domain. This digital copying approach provides accurate current information for protection and control without requiring complex analog sensor hardware
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 system provides a compact, low-loss, high-bandwidth solution for current sensing, enabling rapid protection and accurate control of power converters by reconstructing drive current signals with minimal fluctuations.
Implementation Method 1
a first Rogowski coil wound about the drain connection and a second Rogowski coil wound about the source connection
Data Source
AI summary
A system having: a power switching circuit providing a drive current to a load, and having: a power source; first and second serially connected switches convert DC power from the power source into AC current to form the drive current, or vice versa; a first high-bandwidth current sensor circuit measures high-side current pulses through the first switch and provides a first analog signal, proportional to the high-side pulses; a second high-bandwidth current sensor circuit measures low-side current pulses through the second switch and provides a second analog signal is proportional to the low-side pulses; a signal processing device coupled to the first and second current sensor circuits performs steps of: converting the first analog signal to a first digital signal and the second analog signal to a second digital signal; and reconstructing the drive current and obtaining its cycle average values from the first and second digital signals.