AC Capacitor Induction Heating Neutralization
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Solution Overview
Problem
High voltage AC power capacitors experience significant heating due to dielectric, Ohmic, and inductive losses, limiting their number and configuration in electrical circuits and requiring derating to prevent overheating, despite existing cooling methods.
Innovation Solution
The AC capacitor design features a coaxial system with a protruding rod and bobbin, where the AC current flowing through the bobbin generates a magnetic field that induces a counter-current in the rod, neutralizing the magnetic fields and distributing current uniformly to prevent heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high currents flow through the capacitor at high voltage and frequency, then the capacitor can deliver high power, but induction heating occurs causing excessive temperature rise
Solution Approach 1:
The patent applies the principle of converting harm into benefit by using the magnetic field generated by the AC current flowing through the bobbin to induce a counter-current in the coaxial rod. This counter-current creates an opposing magnetic field that neutralizes the original magnetic field, thereby eliminating the harmful induction heating effect while allowing the capacitor to operate at high power levels
2Productivity
If multiple capacitors are mounted in parallel on a bus, then the system can handle higher currents, but the first or last capacitors in the series overheat due to magnetic field concentration
Solution Approach 1:
The patent eliminates magnetic field concentration effects by using the coaxial rod-bobbin structure where the rod's induced counter-current neutralizes the magnetic field at the capacitor terminals. This allows multiple capacitors to be mounted in parallel without the first or last capacitors overheating, enabling higher current handling capacity across the entire bus system
Solution Approach 2:
The patent achieves homogeneous current distribution and magnetic field cancellation across all capacitors in the parallel configuration. The coaxial rod-bobbin structure ensures that each capacitor experiences the same magnetic field neutralization effect, eliminating the non-uniform heating that previously occurred at the ends of the capacitor series
3Reliability
If derating is applied to prevent overheating, then capacitor life is extended, but the number of capacitors required increases
Solution Approach 1:
The patent eliminates the need for derating by converting the harmful magnetic field into a beneficial counter-field that neutralizes induction heating. This allows capacitors to operate at their full rated power without overheating, extending their operational life while reducing the total number of capacitors required in the system
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 design allows for efficient heat dissipation and extended capacitor life by minimizing induction heating and enabling the use of higher currents without overheating, supporting more efficient capacitor configurations and power usage.
Implementation Method 1
an AC current flows through the bobbin. The AC current flowing through the bobbin generates a magnetic field which in turn induces an AC current in the rod
Implementation Method 2
The magnetic field generated by the AC current flowing through the bobbin and the magnetic field generated by the current flowing in the rod create a coaxial system, practically neutralizing each other
Implementation Method 3
The structure of the AC capacitor facilitates prevention of harmful influence of a magnetic field generated on the AC capacitor when the AC capacitor is connected to an AC current supply bus
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
An AC capacitor including a first electrode with an electrically conductive rod protruding from surface of the first electrode, a second electrode including an opening, a bobbin located between the first and the second electrode the bobbin includes a hollow central section. The axis of the electrically conductive rod protruding from surface of the first electrode is coaxial with axis of the hollow bobbin and the electrically conductive rod passes through the hollow central section of the bobbin and through the opening in the second electrode allowing current flow.