Resonant Switching Power Converter Pre-Charging Circuit
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Solution Overview
Problem
Conventional resonant switching power converters experience high inrush current during switching operations, which can lead to voltage stress and inefficiencies, and require additional components for pre-charging and hot-swapping operations.
Innovation Solution
A resonant switching power converter design that includes a pre-charging circuit with an amplifier, ramp, and pre-charging control circuits to control switch connections, allowing capacitors to be charged in series or parallel, and using inductors to manage voltage conversion, eliminating the need for additional hot-swapping switches and regulators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional switches are used for capacitor switching operations, then voltage conversion can be achieved, but high inrush current occurs during switching
Solution Approach 1:
The pre-charging circuit charges the capacitor to a predetermined voltage before the main switching operation begins. This preliminary charging action prevents the capacitor from being completely uncharged during switching, thereby eliminating the inrush current that would otherwise occur when switching from a fully discharged state.
Solution Approach 2:
The pre-charging circuit acts as an intermediary between the power source and the main switching circuit. It provides a controlled charging path that prepares the capacitor in advance, serving as a buffer that prevents direct high-current transfer during the main switching operation.
2Object-generated harmful factors
If additional pre-charging components are added to reduce inrush current, then inrush current is reduced, but device complexity increases
Solution Approach 1:
The pre-charging circuit is designed to perform multiple functions: it charges the capacitor before switching operations, maintains voltage during idle periods, and enables hot-swapping capability. By consolidating these functions into a single circuit design, the patent avoids adding separate dedicated components for each function, thereby reducing overall complexity.
Solution Approach 2:
The pre-charging circuit is integrated with the main switching circuit rather than being a completely separate system. The same switches and control logic are used for both pre-charging and main voltage conversion operations, merging multiple functions into a unified circuit architecture that reduces component count.
3Power
If capacitors are switched frequently for voltage conversion, then voltage regulation is achieved, but voltage stress on switches increases
Solution Approach 1:
By pre-charging the capacitor to the target voltage before switching operations, the circuit avoids repeated charging and discharging cycles that would subject the switches to high voltage stress. The pre-charged capacitor can be directly connected or disconnected without undergoing full charge-discharge transitions, reducing stress on the switching components.
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 solution reduces unwanted inrush current, achieves soft starting, and supports hot-swapping and parallel operation without additional components, while reducing voltage stress and enabling efficient voltage conversion.
Implementation Method 1
resonant switching power converter capable of executing pre-charging operation
Implementation Method 2
a plurality of switches, which are coupled to the plurality of capacitors, wherein the plurality of switches are configured to operably switch electrical connection relationships of the plurality of capacitors
Implementation Method 3
at least one charging inductor, which is connected in series to at least one of the plurality of capacitors; at least one discharging inductor, which is connected in series to at least one of the plurality of capacitors
Data Source
AI summary
A resonant switching power converter includes: capacitors, switches, at least one charging inductor, at least one discharging inductor and a pre-charging circuit. The pre-charging circuit controls a first switch of the switches when the resonant switching power converter operates in a pre-charging mode, to control an electrical connection relationship between the input voltage and a first capacitor of the capacitors and to control other capacitors of the capacitors, thus controlling the capacitors to be connected in parallel to one another or to be connected in series to one another, so that when a voltage drop across the first capacitor is lower than a predetermined voltage, the voltage drop across each capacitor is charged to the predetermined voltage. After operating in the pre-charging mode, the resonant switching power converter subsequently operates in a resonant voltage conversion mode, to thereby convert an input voltage to an output voltage.