Method and system for feedback-based load control of a climate control system in transport

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Solution Overview

Problem

Transport refrigeration systems face instability due to asynchronous parallel loads causing unstable ripple current demands, which can lead to power shortages and inefficient battery charging in climate control systems during transport.

Innovation Solution

Implementing a feedback-based load control system that monitors current demands from DC components and synchronizes power supply using phase angle control to stabilize power systems and enhance battery charging efficiency by coordinating power requirements among asynchronous parallel loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If asynchronous parallel loads are used in climate control system, then device complexity is reduced, but power system stability deteriorates due to unstable ripple current demands

Engineering Contradiction:
Improveclimate control system complexityVSAvoidpower system stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements periodic action by using phase angle control to periodically modulate the switching of parallel loads. The controller adjusts the phase angle of each load's switching cycle to distribute peak current demands across different time intervals, converting the unstable asynchronous operation into a controlled periodic pattern that stabilizes the power system while maintaining the simplicity of parallel load architecture

Inventive Principle:
Principle #19Periodic action

2Productivity

If multiple DC components operate simultaneously, then productivity of climate control functions is improved, but energy loss increases due to battery depletion and power shortages

Engineering Contradiction:
Improveclimate control function efficiencyVSAvoidbattery charging efficiency
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by having the controller pre-coordinate the switching schedules of multiple DC components before they operate. By calculating and setting appropriate phase angles in advance, the system prepares the power distribution pattern to avoid simultaneous peak demands, thereby preventing power shortages and optimizing battery charging efficiency before the actual loading occurs

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3399618B1Method and system for feedback-based load control of a climate control system in transport
Publication Date: 2023.02.15 THERMO KING CORP
  • EP3399618B1 patent drawingFigure 1
  • EP3399618B1 patent drawingFigure 2
  • EP3399618B1 patent drawingFigure 3

AI summary

Methods and systems for feedback-based load control of a climate control system while in transport are provided. The method can include monitoring a current demand from each of a plurality of DC components of the climate control system. The method can also include determining whether the current demand for two or more of the plurality of DC components is in a discontinuous DC format. Also, the method can include, when two or more of the plurality of DC components is in the discontinuous DC format, determining a synchronization pattern for supplying power to the two or more of the plurality of DC components. Further, the method can include a DC power source of the climate control system directing power to the two or more of the plurality of DC components in the discontinuous DC format based on the synchronization pattern.