Integrated Reactor for Power Conversion Devices
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Solution Overview
Problem
Conventional power conversion devices face challenges in downsizing and reducing current ripple, particularly in bridge-less power factor correction configurations, where integrating reactors for multiple phases leads to increased size and inefficiencies due to leakage magnetic fluxes.
Innovation Solution
A power conversion device with a magnetic core where a DC winding and coupled windings are integrated, allowing magnetic fluxes to merge in the same direction, and switching elements are controlled to manage the relationship between DC and AC current ripples, reducing losses and ripple currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If reactors for multiple phases are integrated into one core, then device size is reduced, but current ripple increases due to leakage magnetic fluxes
Solution Approach 1:
The patent divides the integrated reactor into multiple independent windings (first winding, second winding, third winding) wound around different portions of the magnetic core. Each winding corresponds to a specific phase and can be controlled independently, allowing segmentation of the magnetic flux paths to reduce leakage flux and current ripple while maintaining compact integration.
Solution Approach 2:
The patent applies local quality by winding the coupled windings in opposite directions around different portions of the magnetic core. This creates localized magnetic flux cancellation in specific regions, reducing leakage flux and current ripple in those local areas while maintaining the overall integrated structure.
2Reliability
If windings are arranged to cancel DC magnetic fluxes, then magnetic flux saturation is prevented, but DC inductance can only be formed by leakage magnetic flux
Solution Approach 1:
The patent segments the magnetic core into multiple portions with windings wrapped around each portion. The first and second windings are wound in opposite directions to cancel DC magnetic fluxes and prevent saturation, while the third winding is configured to generate additive magnetic flux for DC inductance formation, separating the functions of saturation prevention and inductance generation.
Solution Approach 2:
The patent introduces a third winding as an intermediary element that mediates between the conflicting requirements of DC flux cancellation and DC inductance formation. This third winding provides the necessary DC inductance through its additive magnetic flux while the first and second windings handle the flux cancellation function.
3Loss of energy
If switching is performed with phases shifted by 360/N degrees, then loss is reduced and input/output current ripple is reduced, but device complexity increases
Solution Approach 1:
The patent implements periodic action by configuring the coupled windings to operate with phase shifts (such as 180 degrees for two-phase operation). This periodic phase shifting reduces current ripple and losses while the integrated magnetic core structure maintains manageable complexity by providing magnetic coupling that naturally coordinates the phase relationships.
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 effectively suppresses losses and current ripples, enabling a more compact power supply filter by optimizing inductance and reducing AC copper losses, while maintaining high power factor operation.
Implementation Method 1
magnetic fluxes generated by currents flowing through the DC winding and the coupled windings merge with each other in the same direction
Implementation Method 2
a reactor formed such that a DC winding and a plurality of coupled windings are wound around one magnetic body
Data Source
AI summary
A power conversion device including: a reactor formed such that a DC winding and a plurality of coupled windings are wound around one magnetic body, one end of the DC winding is connected to a voltage source, one end of each of the plurality of coupled windings is connected to another end of the DC winding, another end of each of the plurality of coupled windings is connected to each intermediate connection point between a plurality of upper and lower arms composed of switching elements, and a control device for controlling the switching elements, wherein switching of the upper arms or the lower arms is controlled in accordance with a magnitude of a duty of the switching operation and a magnitude relationship between DC current ripple and AC current ripple composing current ripple in the coupled windings.