Converter Apparatus Third Switch Power Transfer
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Solution Overview
Problem
Existing high-power inverters face energy losses due to voltage drops in multiple switches during power transfer, and the use of transistors like IGBTs and MOSFETs is not suitable for the 100-500 kVA range, leading to inefficiencies and high energy losses.
Innovation Solution
The introduction of a third switch connected between the input and the modulated signal output, which remains open during the transition from the first to the second switching state, reduces energy losses by allowing power transfer through a single switch, and the use of IGBT-type transistors and field-effect transistors made of silicon carbide or MOSFETs with parallel diodes to manage switching and voltage handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple switches (first switch and second switch) are used in series for power transfer, then voltage handling capability is improved, but energy losses increase due to cumulative voltage drops
Solution Approach 1:
The power transfer path is segmented into two parallel routes: one through the first switch for voltage handling, and another through the third switch for efficient power transfer. This segmentation allows each switch to be optimized for its specific function, reducing cumulative losses while maintaining voltage handling capability.
Solution Approach 2:
The third switch acts as an intermediary element that provides a low-loss alternative path for power transfer. By introducing this intermediate component, the system achieves efficient power transfer without requiring current to pass through multiple switches in series, thus reducing energy losses.
2Strength
If IGBT-type transistors are used for switching, then voltage handling is improved, but switching energy losses increase
Solution Approach 1:
Different switch types are assigned to different functional requirements: IGBT-type transistors are used where voltage handling is critical, while MOSFETs are used where low switching losses are prioritized. This local optimization of component quality allows the system to achieve both high voltage handling and low switching losses in different parts of the circuit.
Solution Approach 2:
The system employs a composite switching architecture that combines IGBT-type transistors and MOSFETs in parallel configurations. This composite approach leverages the complementary strengths of both transistor types, achieving a balance between voltage handling capability and switching efficiency that neither component could achieve alone.
3Loss of energy
If the third switch is closed during power transfer, then energy losses are reduced, but control complexity increases
Solution Approach 1:
The third switch is controlled to close and open periodically in synchronization with the switching cycles of the first and second switches. This periodic action ensures that the low-loss power transfer path is activated only when needed, reducing energy losses during critical power transfer intervals while maintaining manageable control complexity through rhythmic, predictable switching patterns.
Data Source
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AI summary
A converter (21) for providing an alternating voltage on a modulated signal output (MS) comprising two switching units (UC1, UC4), each having a DC voltage input (P, N) and a switching output (S1, S4) for providing pulses varying between the input voltage in a first switching state and a reference voltage in a second switching state. Each switching unit has a first switch (T1, T4) connected between the input and the switching output to establish said first switching state. Each switching unit has a second switch (T2, T3) connected between said switching output and said modulated signal output to activate said switching unit, and a third switch (TX1, TX4) connected between the input of said switching unit and the modulated signal output. An uninterruptible power supply (101) equipped with this converter.