Power Converter Mode Switching for Capacitor Size Reduction

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Solution Overview

Problem

Existing power-converting devices face challenges in maintaining a constant output voltage due to capacitor voltage fluctuations, leading to inefficiencies and increased size requirements for capacitors to manage these fluctuations.

Innovation Solution

A power-converting device with a conversion circuit and controller that switches between sustaining, charging, and discharging modes based on a comparison between a signal wave and a reference wave, using a capacitor with a small capacitance to minimize voltage fluctuations and achieve desired output voltages, while reducing the overall device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a capacitor with relatively large capacitance is used to suppress voltage fluctuations, then voltage stability is improved, but device size increases

Engineering Contradiction:
Improvevoltage stabilityVSAvoidcapacitor size
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The patent applies dynamics by switching between multiple operation modes (first operation mode and second operation mode) depending on the instantaneous voltage level. The controller dynamically adjusts the circuit configuration based on real-time voltage conditions, allowing the system to maintain voltage stability without requiring a large fixed capacitance. This dynamic switching enables effective voltage suppression with smaller capacitors.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes operational parameters by transitioning between different operation modes with distinct circuit configurations. In the first operation mode, the circuit operates with one set of connections, while in the second operation mode, the connections are reconfigured. This parameter change allows the system to adapt to voltage fluctuations and maintain stability without increasing capacitor size, as the control strategy adjusts rather than relying solely on increased capacitance.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If multiple operation modes are implemented to maintain voltage stability, then voltage control precision is improved, but device complexity increases

Engineering Contradiction:
Improvevoltage control precisionVSAvoidcontrol complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements feedback by continuously monitoring the voltage level and using this information to determine which operation mode to activate. The controller compares the instantaneous voltage against reference levels and switches modes accordingly, creating a closed-loop control system. This feedback mechanism enables precise voltage control while keeping the control logic relatively simple, as it relies on straightforward voltage threshold comparisons rather than complex control algorithms.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3214749B1Power-converting device, and power conditioner using same
Publication Date: 2019.01.23 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3214749B1 patent drawingFigure 1
  • EP3214749B1 patent drawingFigure 2A~2B
  • EP3214749B1 patent drawingFigure 3A~3B

AI summary

In order to provide a power-converting device for reducing a capacitor size and a power conditioner therewith, a controller (6) switches between modes each having a different connection state of a DC power supply (100) and the capacitor with respect to first and second output points (103, 104) by controlling switches. A generation unit (3) generates a reference wave including at least one carrier wave. The modes are classified into a sustaining mode in which no current is caused to flow to the capacitor, a charging mode in which a current is caused to flow to the capacitor, and a discharging mode in which a current in a direction opposite to that in the charging mode is caused to flow to the capacitor. The controller (6) switches between the sustaining mode and a charging or discharging mode according to the comparison result between a signal wave and the reference wave.