Near Zero Current-Ripple Inversion Circuit Topology
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Solution Overview
Problem
Conventional half-bridge power converters experience high input current-ripple and related electromagnetic interference, leading to increased di/dt noise, which complicates circuit implementation and reduces efficiency, while also requiring higher voltage rating switches that increase conduction losses.
Innovation Solution
The design incorporates a power inversion circuit with a topology that includes clamping capacitors and leakage inductance as a lossless snubber circuit to recycle leakage energy, reducing input current-ripple and voltage stress on semiconductor switches, and employs simple control timing for driver signals to minimize complexity and conduction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional half-bridge converter topology is used, then circuit implementation is simple, but input current-ripple is high causing increased electromagnetic interference
Solution Approach 1:
The patent divides the single primary winding into two separate primary windings (P1 and P2) with identical turns. These two windings are controlled independently with complementary duty cycles, allowing their current ripples to cancel each other out. This segmentation approach reduces the overall current-ripple and electromagnetic interference while maintaining circuit simplicity.
Solution Approach 2:
The patent employs periodic switching of the two primary windings with complementary duty cycles (D and 1-D). By alternately activating the windings in a periodic manner, the current ripples occur at different phases and cancel each other, reducing electromagnetic interference while maintaining continuous power transfer.
2Object-generated harmful factors
If higher voltage rating switches are used to reduce current-ripple, then electromagnetic interference is reduced, but conduction losses increase
Solution Approach 1:
The patent changes the voltage stress parameter on the switches by using two primary windings with complementary duty cycles. This configuration limits the voltage stress on each switch to a lower level, allowing the use of switches with lower voltage ratings and lower RDS(on), thereby reducing conduction losses while maintaining electromagnetic interference reduction.
3Object-generated harmful factors
If interleaving two identical power converters is used to reduce current-ripple, then electromagnetic interference is reduced, but circuit complexity increases
Solution Approach 1:
The patent merges the functions of two interleaved converters into a single converter by using two primary windings on the same transformer core. This integration achieves current-ripple cancellation and electromagnetic interference reduction while avoiding the complexity of implementing two separate converters, as the windings share common components like the transformer core and output circuitry.
4Loss of energy
If clamping diodes are added to limit voltage on switches, then lower voltage rating switches can be used, but control circuit complexity increases
Solution Approach 1:
The patent employs clamping diodes that automatically limit the voltage on switches during their off-state without requiring active control. The diodes inherently clamp the voltage to a safe level, allowing the use of lower voltage rating switches with reduced conduction losses, while the control circuit only needs to manage the switching signals without additional complexity for voltage protection.
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 achieves near zero input or output current-ripple, reduces electromagnetic interference, and improves efficiency by using lower voltage rating switches with lower RDS(on) and forward voltage drop, resulting in reduced conduction losses and simplified control circuits.
Implementation Method 1
leakage inductance and capacitor being a lossless snubber circuit for recycling the leakage energy
Implementation Method 2
a transformer T1 has a primary winding P1 connected between center nodes of the two series-connected capacitors (C1, C2) and switches (Q1, Q2). Alternative operation of the switches Q1 and Q2 results in the generation of an AC output voltage on a secondary winding S1 of the transformer T1
Data Source
AI summary
The present invention relates to a near zero current-ripple inversion circuit including top and bottom cells, a transformer (T1) comprising primary windings (P1, P2) and a secondary winding (S1), and at least one middle cell connected in series between the top and bottom cells. The top cell comprises two capacitors (C1, C2) and a switch (Q1) each connecting to the middle cell, and an inductor (Lr1) and the primary winding (P1) connected in series between the capacitor (C1) and switch (Q1), wherein the switch (Q1) is connected to the capacitors (C1, C2) respectively. The bottom cell comprises a capacitor (C3) and a switch (Q2) each connecting to the middle cell, and an inductor (Lr2) and the primary winding (P2) connected in series between the capacitor (C3) and switch (Q2), wherein the primary winding (P2) is connected to the middle cell, and the capacitor (C3) and switch (Q2) are connected.