Inverter Idle Mode Control for Energy Consumption Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional converters exhibit poor no-load behavior when no energy flow is desired between connection sides, leading to higher energy consumption during idle states.

Innovation Solution

A converter with a control device that enables two idle operating modes: one where at least one sub-module is active and another where all sub-modules are inactive, switching between these modes based on energy store state and voltage conditions to minimize energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional converters operate in idle state with sub-modules active, then the energy stores can be maintained charged, but energy consumption increases due to continuous current flow

Engineering Contradiction:
Improveenergy store charge maintenanceVSAvoidenergy consumption during idling
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The converter dynamically switches between two idle operating modes based on real-time monitoring of energy store charge levels. The control device transitions from first idle mode (with active sub-modules and higher energy consumption) to second idle mode (with inactive sub-modules and minimal energy consumption) when charge thresholds are met, creating a dynamic adaptation to operational conditions that optimizes energy usage while maintaining reliability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameters of the sub-modules by switching between two distinct idle modes. In the first idle mode, sub-modules operate with specific voltage and current parameters to maintain energy store charge. In the second idle mode, parameters are changed to minimize energy consumption by deactivating sub-modules. This parameter switching resolves the contradiction between maintaining charge and reducing energy use

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If all sub-modules are kept inactive to minimize energy consumption, then energy efficiency improves, but voltage levels may drop below operational thresholds

Engineering Contradiction:
Improveenergy consumption during idlingVSAvoidvoltage level maintenance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The control device implements a feedback mechanism that continuously monitors the charge level of energy stores and voltage levels of module series circuits. When voltage or charge thresholds are approached during second idle mode operation, the system receives feedback and automatically transitions to the first idle mode to recharge energy stores, ensuring voltage levels remain above operational thresholds while maximizing energy efficiency during appropriate periods

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary recharging actions by transitioning to the first idle mode before voltage levels drop below critical thresholds. This proactive approach ensures that when the converter needs to transition to the energy-efficient second idle mode, the voltage levels are already sufficient, preventing future voltage drops and maintaining system reliability

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If frequent switching between idle modes occurs, then energy optimization is achieved, but hardware stress and voltage transients increase

Engineering Contradiction:
Improveenergy consumption optimizationVSAvoidvoltage transients and hardware stress
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The converter employs periodic action by establishing defined threshold levels for energy store charge and voltage that dictate mode transitions. Rather than switching frequently or continuously, the system transitions between idle modes only when predetermined thresholds are reached, creating a periodic rather than continuous switching pattern. This reduces the frequency of transitions and associated voltage transients while still achieving energy optimization over time

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control device implements beforehand cushioning by monitoring voltage levels and charge states continuously and anticipating the need for mode transitions before critical conditions occur. By detecting approaching thresholds and preparing for transitions in advance, the system can execute mode changes more smoothly with reduced voltage transients and hardware stress, rather than reacting abruptly when thresholds are exceeded

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3866326A1Converter and method for the operation of same
Publication Date: 2021.08.18 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3866326A1 patent drawingFigure 1
  • EP3866326A1 patent drawingFigure 2~3
  • EP3866326A1 patent drawingFigure 4

AI summary

The invention relates, inter alia, to an inverter (10) with a first connection side (AS1) and a second connection side (AS2), wherein the inverter (10) has at least one series module connection (TS) with two electrically series-connected sub-modules (SM) and a control device (20) for controlling the sub-modules (SM), wherein the sub-modules (SM) each comprise an energy storage device and at least two switching elements (S), of which at least one switching element (S) is switched on during active operation of the sub-module (SM), and wherein the control device (20) is suitable to ensure a predetermined energy flow between the two connection sides (AS1, AS2) by controlling the switching elements (S) or to enable an idle state in which there is no energy flow between the two connection sides (AS1, AS2) by controlling the switching elements (S).According to the invention, the control device (20) is designed in such a way that it enables at least two idle operating modes (LL1, LL2), namely a first idle operating mode (LL1) in which at least one of the sub-modules (SM) is in active operation, and a second idle operating mode (LL2) in which all sub-modules (SM) are inactive, and the control device (20) is also designed in such a way that, when idle operation is desired, it sets the second idle operating mode (LL2) as long as the state of charge of the or a predetermined group of energy storage devices of the inverter (10) meets a predetermined charging condition, and otherwise sets the first idle operating mode (LL1).