Rotating Electrical Machine Resonant Current Reversal
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Solution Overview
Problem
Current rotating electrical machines experience significant losses when altering current directions in their windings, which can be improved upon.
Innovation Solution
The implementation of a rotating electrical machine with serially connected switching cells and capacitors forming resonant LC circuits, allowing for efficient current direction alteration through natural oscillations, reducing switching losses and enabling higher power handling by arranging branches in parallel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current direction is altered in windings using conventional switching methods, then current direction control is achieved, but significant switching losses occur
Solution Approach 1:
The patent applies resonant oscillation principles to the electrical circuit, using the natural resonant frequency of the LC circuit formed by the capacitor and winding inductance to perform current direction reversal. The switching device operates at or near the resonant frequency, allowing current to naturally oscillate through zero and reverse direction without forced commutation, thereby minimizing switching losses.
Solution Approach 2:
The patent changes the operating parameters by introducing a capacitor to create a resonant circuit, transforming the switching process from a forced high-loss operation to a natural resonant oscillation. The switching frequency and timing are adjusted to match the resonant characteristics of the LC circuit, enabling efficient current reversal.
2Power
If multiple switching cells are connected in series to increase power handling, then power capacity increases, but device complexity increases
Solution Approach 1:
The patent divides the overall power system into multiple series-connected switching cells, each handling a portion of the total voltage and power. This segmentation allows the system to achieve high power capacity while maintaining manageable complexity at each cell level, as each cell operates independently with its own capacitor and switching device.
Solution Approach 2:
Each switching cell in the series connection serves multiple functions: voltage blocking, current direction control, and resonant oscillation generation. The capacitor in each cell not only provides resonance for its associated winding but also contributes to the overall voltage handling capability of the series string, reducing the need for additional dedicated components.
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 minimizes losses during current direction changes and enhances the machine's power capacity by leveraging resonant circuits and strategic capacitor placement, achieving efficient operation with reduced complexity and risk of resonance.
Implementation Method 1
each current reverser comprises a capacitor arranged to form a resonant circuit in cooperation with the winding subsection
Implementation Method 2
it is the natural oscillation of voltages and currents of the resonant LC circuit which provokes the alteration of the current flowing through winding subsection
Data Source
AI summary
A rotating electrical machine including a stator or rotor including a plurality of serially connected switching cells. Each switching cell includes a winding subsection and a current reverser arranged to controllably alter a current direction through the winding subsection, and each current reverser includes a capacitor arranged to form a resonant circuit in cooperation with the winding subsection.