Power Conversion Apparatus Secondary Side Amplitude Control

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Solution Overview

Problem

Existing power conversion apparatuses experience significant power losses due to circulating currents generated in the inverter circuit when controlling the amplitude of output voltage or current, particularly in full-bridge type inverter circuits.

Innovation Solution

The power conversion apparatus employs a configuration where the control unit manages the switching devices in the secondary side to prevent circulating currents by controlling the amplitude of output voltage or current without relying on the inverter circuit in the primary side, using specific timing controls for the switching devices to maintain zero transformer current during power supply and regeneration modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the inverter circuit controls the amplitude of output voltage or current, then the output amplitude can be adjusted, but circulating currents are generated causing power losses

Engineering Contradiction:
Improveoutput amplitude controlVSAvoidpower losses
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the amplitude control function from the inverter circuit on the primary side and relocates it to switching devices on the secondary side. This separation eliminates the source of circulating currents while preserving the amplitude control capability, thereby resolving the contradiction between adaptability and energy loss

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary control mechanism where the control unit manages secondary side switching devices to achieve amplitude control. This intermediary approach allows control without requiring the primary side inverter to operate in amplitude modulation mode, thus preventing circulating current generation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the inverter circuit is used for power conversion, then DC power can be converted to AC power, but circulating currents are generated in the inverter circuit

Engineering Contradiction:
Improvepower conversionVSAvoidcirculating currents
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent segments the power conversion system into distinct functional components: the inverter circuit for basic DC-to-AC conversion and secondary side switching devices for amplitude control. This segmentation isolates the harmful circulating current generation to minimal periods while maintaining continuous power conversion functionality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs periodic action by controlling the secondary side switching devices to operate in specific time periods. The switching devices are activated during periods when the transformer current is zero or minimal, creating a periodic pattern that eliminates circulating currents while maintaining power conversion

Inventive Principle:
Principle #19Periodic action

3Loss of energy

If the switching devices are controlled to prevent circulating currents, then power losses are reduced, but the control complexity increases

Engineering Contradiction:
Improvepower lossesVSAvoidcontrol complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements feedback control where the control unit monitors transformer current and switching device states to optimize the timing of amplitude control operations. This feedback mechanism automates the complex timing coordination, reducing the perceived control complexity while maintaining the benefit of eliminated circulating currents

Inventive Principle:
Principle #23Feedback

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 power losses by eliminating circulating currents in the inverter circuit, allowing for efficient power supply and regeneration modes with minimal wasteful regenerative or supply currents.

Implementation Method 1

a transformer 9 that includes a primary winding 19 and a secondary winding 21, which is magnetically coupled with the primary winding 19

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3007348B1Power conversion apparatus
Publication Date: 2020.01.08 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3007348B1 patent drawingFigure 1
  • EP3007348B1 patent drawingFigure 2
  • EP3007348B1 patent drawingFigure 3

AI summary

A control unit controls the amplitude of at least either an output voltage or an output current by shifting at least either a first on time or a second on time.