Reversible AC-DC Converter Triac Topology
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Solution Overview
Problem
Conventional totem pole converters are unidirectional and lack the capability to handle inrush current effectively, limiting their application in reversible AC-DC and DC-AC conversion scenarios.
Innovation Solution
The proposed solution involves a reversible totem pole converter architecture using two field-effect transistors in series with an inductive element and replacing diodes with triacs, allowing for bidirectional operation and eliminating the need for an inrush current limiting circuit by utilizing triacs that are continuously turned on during alternating voltage phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional totem pole converter architecture is used, then the converter can operate in AC-DC mode, but it cannot operate in DC-AC mode and requires inrush current limiting circuits
Solution Approach 1:
The patent applies universality by making the converter circuit capable of both AC-DC and DC-AC operation modes. The same circuit topology with triacs and field effect transistors serves dual purposes: rectification in AC-DC mode and inversion in DC-AC mode, eliminating the need for separate circuits for each function.
Solution Approach 2:
The patent employs inversion by reversing the operational mode of the converter. By controlling the triacs and field effect transistors appropriately, the circuit can operate in reverse direction, converting DC back to AC, thus achieving bidirectional functionality from a unidirectional base design.
2Device complexity
If diodes are used in the conventional totem pole converter, then the circuit is simple, but inrush current must be limited requiring additional circuits
Solution Approach 1:
The patent changes the parameter of the switching element from diode (unidirectional, passive) to triac (bidirectional, controllable). This parameter change allows the triac to be turned on continuously during its conduction phase, eliminating inrush current peaks without requiring additional limiting circuits, thus resolving the contradiction between circuit simplicity and inrush current control.
3Loss of energy
If unidirectional converter is used, then the circuit is simpler, but conduction losses are higher and efficiency is reduced
Solution Approach 1:
The patent applies dynamics by making the converter architecture adaptable and flexible. The circuit can dynamically switch between AC-DC and DC-AC modes, and the triacs can be controlled to conduct continuously during their respective phases, optimizing current flow paths and reducing conduction losses compared to fixed unidirectional designs.
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 configuration enables efficient bidirectional operation, reducing conduction losses and eliminating the requirement for an inrush current limiting circuit, thereby enhancing the converter's efficiency and versatility in both AC-DC and DC-AC conversion modes.
Implementation Method 1
an inductive element connecting a first midpoint of the series association of the two transistors to a first terminal intended for an alternating voltage
Data Source
Figure 1~2
Figure 3A~3H
Figure 4A~4H
AI summary
The invention relates to a reversible AC-DC converter, comprising: a first field-effect transistor (S1) and a second field-effect transistor (S2) in series between a first terminal (11) and a second terminal (12) of a DC voltage (Vdc); an inductive element (L1) connecting a first midpoint (13) of the series association of the two transistors to a first terminal (15) of an AC voltage (Vac); a first triac (T1) and a second triac (T2) in series between the DC voltage terminals, a second midpoint (17) of the series association of the two triacs being connected to a second terminal (16) of the AC voltage.