Hybrid Buck Converter With Zero-Voltage Switching for High Step-Down
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Solution Overview
Problem
Existing DC-DC converters in distributed power architectures face challenges in achieving high efficiency and power density, particularly when dealing with high step-down ratios, and lack effective soft switching mechanisms to minimize switching losses.
Innovation Solution
A DC-DC switching hybrid converter incorporating a switched-capacitor converter circuit with a coupled inductor or transformer, combined with a zero-voltage switching network, to achieve a fixed step-down ratio and reduce component stress and switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional DC-DC converter is used with high step-down ratio, then the voltage conversion is achieved, but the efficiency decreases due to increased switching losses
Solution Approach 1:
The zero-voltage switching network performs preliminary action by discharging the switches between switching states, ensuring that switches are discharged before the next switching event occurs. This preliminary discharge action eliminates voltage spikes and reduces switching losses, directly resolving the contradiction between achieving voltage conversion and minimizing energy loss.
Solution Approach 2:
The zero-voltage switching network acts as an intermediary between the switched-capacitor converter circuit and the coupled inductor/transformer. It mediates the switching transitions by providing a controlled discharge path, thereby reducing the harmful switching effects while maintaining the high step-down ratio voltage conversion functionality.
2Loss of energy
If high step-down ratio is implemented, then voltage conversion is achieved, but power density decreases
Solution Approach 1:
The patent merges the switched-capacitor converter circuit with the coupled inductor/transformer in a hybrid configuration. This merging allows the system to achieve high step-down ratios while maintaining compact size and high power density, as the combined topology utilizes space and components more efficiently than separate stages would.
Solution Approach 2:
The hybrid converter employs dynamic switching control where the switched-capacitor circuit and coupled inductor/transformer work in coordinated switching states. This dynamic operation enables the system to adaptively manage power transfer, achieving both high voltage conversion ratios and high power density through optimized switching sequences.
3Loss of energy
If conventional switching is used, then voltage conversion is achieved, but component stress increases due to current spiking
Solution Approach 1:
The zero-voltage switching network performs preliminary discharge of switches between switching states, preventing voltage spikes before they occur. This preliminary action protects components from excessive stress and current spiking, resolving the contradiction between achieving voltage conversion and minimizing component stress.
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 hybrid converter supports high step-down ratios with high efficiency and power density, while enabling soft switching to minimize current spiking and achieve low switching losses.
Implementation Method 1
a zero-voltage switching network coupled between the second node and the ground potential to discharge voltages at some of the switches between switching states of the hybrid converter
Implementation Method 2
first and second inductors each having a first terminal coupled to the output node, the first and second inductors being configured as coupled inductors
Implementation Method 3
a transformer including a first primary winding and a second primary winding inductively coupled to a first secondary winding and a second secondary winding, center taps of the first and second primary windings being coupled to respective second and third capacitors, each primary winding and each secondary winding have a turns ratio of N1/N2
Implementation Method 4
a first capacitor coupled between a first node and a second node, the first node being switchably coupled to the input voltage and the second node being switchably coupled to a ground potential; and second and third capacitors coupled to the set of switches in a cross-coupled configuration
Data Source
AI summary
A non-isolated DC-to-DC switching hybrid converter is implemented using a cross-coupled series-capacitor quadruple step-down buck converter topology. In some embodiments, the DC-to-DC switching hybrid converter includes a switched-capacitor converter circuit and incorporates a zero-voltage switching network to implement soft switching and a coupled inductor to realize a fixed step-down ratio. The hybrid converter is capable of supporting a high step-down ratio (such as 8:1) while providing high efficiency. In other embodiments, the DC-to-DC switching hybrid converter incorporates a transformer in place of the coupled inductor to further increase the step-down ratio.