Parallel Branch Rectifying Circuit for High-Frequency Soft Switching
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Solution Overview
Problem
Existing rectifying circuits face inefficiencies at high frequencies due to parasitic elements and 'hard switching' issues, limiting their operational frequency and increasing energy losses, particularly in synchronous rectification systems.
Innovation Solution
A rectifying circuit design featuring parallel inductive elements and electric current controlling elements, such as transistors, which operate efficiently up to high frequencies without the need for bootstrap circuits and minimize losses by using transistors in anti-series configuration, allowing for selective voltage adjustment and inversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional rectifying circuits (diodes, MOSFETs) are used, then rectification function is achieved, but energy losses increase and operational frequency is limited due to parasitic elements and hard switching
Solution Approach 1:
The rectifying circuit is divided into two parallel branches, each containing a controllable electric current element (transistor). This segmentation allows independent control of each branch, enabling soft switching operation and reducing parasitic effects that limit frequency and increase losses in conventional single-branch rectifiers
Solution Approach 2:
The patent employs dynamic control of the electric current controlling elements (transistors) through complementary switching signals. The transistors are switched on and off dynamically based on the input voltage polarity, enabling operation at high frequencies (tens or hundreds of MHz) without the hard switching losses that plague conventional circuits
2Loss of energy
If synchronous rectification with transistors is used, then energy losses are reduced, but complexity increases due to need for control circuits and bootstrap circuits
Solution Approach 1:
The rectifying circuit uses the input voltage itself to control the switching of the transistors. When the input voltage is positive, one transistor conducts; when negative, the other conducts. This self-controlled operation eliminates the need for external bootstrap circuits and complex control logic, reducing device complexity while maintaining low losses
Solution Approach 2:
The control function is merged into the rectification process itself. The transistors are configured such that their gate control is derived from the input voltage polarity, combining the rectification and control functions into a single integrated operation rather than separate stages
3Productivity
If Graetz bridge rectifier is used, then both positive and negative half-waves are rectified, but diode losses double compared to single diode solution
Solution Approach 1:
Instead of using four diodes in series as in the Graetz bridge, the patent inverts the approach by using two transistors in parallel branches with complementary switching. Current flows through only one transistor per half-cycle rather than two diodes in series, halving the conduction losses while still rectifying both half-waves
4Loss of energy
If centre-tapped transformer is used, then diode losses are halved compared to Graetz bridge, but cost, weight, and bulk increase substantially
Solution Approach 1:
The patent extracts and eliminates the transformer component entirely from the rectifying circuit. By using direct parallel branches with controllable electric current elements, the circuit achieves efficient rectification without the weight, bulk, and cost of a centre-tapped transformer, while also avoiding transformer losses at high frequencies
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 proposed solution significantly reduces energy losses and enables efficient operation at frequencies up to tens or hundreds of MHz, providing a compact, cost-effective, and efficient rectification with adjustable output voltage, eliminating the need for transformers and reducing bulk and cost.
Implementation Method 1
A rectifying circuit (10) comprises a first circuit branch (20) and a second circuit branch (30) in parallel between an output node (Out) and a reference node (GND). Each circuit branch (20, 30) comprises an inductive element (L1, L2) and an electric current controlling element (23, 33).
Data Source
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AI summary
A rectifying circuit (10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6) comprising a first circuit branch (20) and a second circuit branch (30) in parallel between an output node (Out) and a reference node (GND), each circuit branch (20, 30) comprising an inductive element (L1, L2) in series with an electric current controlling element (23, 33) and an input node (In1, In2) arranged between the inductive element (L1, L2) and the electric current controlling element (23, 33), a voltage that is variable over time being applied between the input nodes (In1, In2) during the operation of the rectifying circuit.