Power Converter Capacitor-Switch Parallel Structure for Voltage Peak Reduction
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Solution Overview
Problem
Current power converters face inefficiencies and potential damage due to high voltage peaks generated by current sampling circuits connected in series with switches, leading to increased noise and switching losses.
Innovation Solution
A power converter design incorporating a capacitor-switch parallel structure, where a smaller capacitor is connected in parallel with a switch unit and a larger capacitor is connected in series with the current sampling unit, effectively reducing voltage peaks and maintaining accurate current sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current sampling circuit is directly connected in series to a switch (MOSFET), then current sampling accuracy is improved, but voltage peak increases causing high frequency noise and decreased efficiency
Solution Approach 1:
The patent divides the sampling circuit into two separate paths: one path with the first capacitor and current sampling unit for accurate current measurement, and another path with the second capacitor for voltage peak suppression. This segmentation allows each path to perform its specific function without interfering with the other, resolving the contradiction between sampling accuracy and voltage peak reduction.
Solution Approach 2:
The patent introduces capacitors as intermediary elements between the switch and sampling circuit. The first capacitor coupled to the switch terminal and the second capacitor in the sampling path act as mediators that filter voltage peaks while allowing accurate current sampling, thus eliminating the direct harmful interaction between the sampling circuit and voltage peaks.
2Object-generated harmful factors
If gate driving resistance is increased or high frequency capacitor is connected in parallel to decrease switching speed, then voltage peak is reduced, but switching loss increases decreasing efficiency
Solution Approach 1:
The patent changes the circuit configuration parameters by introducing a specific capacitor arrangement (first capacitor coupled to switch terminal, second capacitor in series with sampling unit) rather than changing the switching speed. This parameter change allows voltage peak reduction through capacitive filtering while maintaining optimal switching speed, thus avoiding increased switching losses.
3Object-generated harmful factors
If snubber circuit is used to absorb power of voltage peak, then peak value is reduced, but switching speed decreases increasing switching loss
Solution Approach 1:
Instead of using a traditional snubber circuit that slows down switching, the patent segments the circuit into separate capacitive filtering paths. The first capacitor handles voltage peak absorption at the switch terminal, while the second capacitor maintains sampling accuracy, allowing fast switching to be preserved while still reducing voltage peaks.
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 configuration reduces high frequency noise, enhances converter efficiency, and prevents permanent damage to switch elements by mitigating voltage peaks while preserving current sampling accuracy.
Implementation Method 1
The first capacitor and the switch unit are connected to each other in parallel to form a capacitor-switch parallel structure. The capacitance of the second capacitor is more than ten times larger than the capacitance of the first capacitor.
Implementation Method 2
The current sampling unit is configured to detect at least one of the current of the first switch and the current of the second switch, and the current sampling unit and the capacitor-switch parallel structure are connected to each other in series to form a capacitor-sampling unit series structure.
Data Source
AI summary
A power converting circuit includes a converter. The converter receives and converts an input power to provide power for a load. The converter includes a power storage unit, a switch unit, a capacitor unit, and a current sampling unit. The power storage unit includes input and output terminals. The switch unit includes first and second switches, which are series connected at a common terminal, and the common terminal is coupled to the output terminal of the power storage unit. The capacitor unit includes first and second capacitors. The first capacitor and the switch unit are parallel connected to form a capacitor-switch parallel structure. The second capacitor capacitance is more than ten times larger than the first capacitor capacitance. The current sampling unit and the capacitor-switch parallel structure are series connected to form a capacitor-sampling unit series structure. The capacitor-sampling unit series structure and the second capacitor are parallel connected.