Soft-Switching PWM DC-DC Converter for Lower Switching Loss
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Solution Overview
Problem
Existing switch-mode DC-DC power converters face challenges in improving power density and conversion efficiency, particularly when delivering large amounts of electrical power, due to high switching losses and thermal dissipation issues, which increase design complexity and cost.
Innovation Solution
A switch-mode DC-DC power converter that combines a hard-switching circuit with a soft-switching circuit, incorporating a first capacitance, inductance, and a controlled discharger to minimize switching losses by using a soft-switching circuit to store and recover electrical energy during hard-switching transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hard-switching is used to achieve fast switching and good dynamic control, then switching speed is improved, but switching losses increase due to charging and discharging of parasitic capacitances
Solution Approach 1:
The patent segments the switching process into two distinct modes: hard-switching for fast response and dynamic control, and soft-switching for low-loss energy transfer. The dual-mode operation divides the switching functions between hard-switching circuit (for speed) and soft-switching circuit (for efficiency), resolving the contradiction between switching speed and switching losses.
Solution Approach 2:
The patent changes the switching parameters dynamically by transitioning between hard-switching and soft-switching modes. During hard-switching mode, high-frequency switching is employed for fast response. During soft-switching mode, the switching frequency and timing are adjusted to achieve zero-voltage or zero-current switching, minimizing switching losses while maintaining acceptable speed performance.
2Power
If switching frequency is increased to use small and lightweight magnetic components, then power density is improved, but switching losses increase due to parasitic capacitance charging and discharging
Solution Approach 1:
The patent applies segmentation by dividing the power conversion function into hard-switching circuit (providing high-frequency switching for small magnetic components and high power density) and soft-switching circuit (providing low-loss energy transfer). This allows the system to operate at high frequencies without proportionally increasing switching losses.
Solution Approach 2:
The patent converts the harmful effect of parasitic capacitance charging and discharging into a beneficial energy transfer mechanism. The soft-switching circuit recovers energy that would otherwise be lost during switching transitions, transforming the harmful parasitic effects into useful energy transfer, thereby enabling high power density without proportional increase in losses.
3Loss of energy
If soft-switching is used to reduce switching losses, then energy efficiency is improved, but device complexity increases due to additional circuit components
Solution Approach 1:
The patent merges the hard-switching circuit and soft-switching circuit into a unified dual-mode power converter system. The soft-switching components (capacitors, inductors, diodes) are integrated with the hard-switching topology, allowing the system to achieve low switching losses without requiring entirely separate soft-switching circuitry. The merged design shares common components and reduces overall complexity compared to standalone soft-switching solutions.
Solution Approach 2:
The patent implements multi-functionality where the soft-switching components serve multiple purposes: energy storage, voltage clamping, current limiting, and loss reduction. The capacitors and inductors in the soft-switching circuit not only reduce switching losses but also provide voltage regulation, current shaping, and protection functions, thereby reducing the need for additional dedicated components and lowering overall circuit complexity.
4Power
If high-power DC voltage conversion is performed to deliver large amounts of electrical power, then power output is improved, but thermal dissipation requirements increase, resulting in higher design complexity and cost
Solution Approach 1:
The patent converts the harmful energy losses that would normally be dissipated as heat into useful energy transfer through the soft-switching circuit. By recovering energy during switching transitions and transferring it through the soft-switching path, the system minimizes thermal dissipation while maintaining high power output capability, thereby reducing thermal management requirements and associated design complexity.
Solution Approach 2:
The patent changes the energy dissipation parameters by operating in dual-mode: hard-switching for fast response and soft-switching for low-loss energy transfer. During soft-switching operation, the switching losses are reduced to minimal levels, significantly lowering thermal dissipation requirements for high-power applications. This parameter change enables high power output without proportionally increasing thermal management complexity.
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 combined circuit reduces switching losses and improves conversion efficiency, allowing for higher power density and reduced energy losses, while maintaining a simple and reliable design.
Implementation Method 1
a second inductance coupled to the first capacitance and to at least one of the plurality of semiconducting devices
Implementation Method 2
a first rectifying element coupled to the second inductance and the second capacitance to charge the second capacitance by forward biasing the first rectifying element based on an induced voltage across the second inductance
Implementation Method 3
a first capacitance coupled in parallel across one of the at least two power ports at one side of the hard-switching circuit... a second capacitance
Data Source
AI summary
A switch-mode DC-DC power converter including an input port and an output port, wherein the switch-mode DC-DC power converter includes a hard-switching circuit. The switch-mode DC-DC power converter further includes a first capacitance, a first inductance and a soft-switching circuit. The first capacitance is coupled in parallel across one of input and output ports at one side of the hard-switching circuit whereas the first inductance is coupled in series with another of the input and output ports and the hard-switching circuit at a second side of the hard-switching circuit opposite the first capacitance. A soft-switching circuit includes a second capacitance, a second inductance, a first rectifying element and a controlled discharger. The first rectifying element is coupled to the second inductance and the second capacitance. The controlled discharger is coupled to the second capacitance.