Multi-Power Converter Unit for Trailer Refrigeration Flexibility
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Solution Overview
Problem
Trailer refrigeration units face challenges with diesel engine-driven systems due to high fuel costs, emissions, noise pollution, and inefficiencies, while electric TRUs lack flexibility in incorporating cleaner power sources and efficient part-load operation.
Innovation Solution
A multi-power converter unit (MPCU) that selectively couples various power sources, including diesel generators, onboard engines, and energy storage, to a compressor and fan system, controlled by a microcontroller to optimize operation based on environmental parameters, allowing for flexible power usage and efficient compressor speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diesel engine driven TRU is utilized, then refrigeration capability is maintained, but fuel costs, emissions, and noise pollution increase
Solution Approach 1:
The power converter unit is designed to accept multiple types of power sources (diesel engine, solar panels, grid power) and convert them all to DC power for the refrigeration system. This multi-functionality allows the system to maintain reliable refrigeration capability while selecting cleaner power sources to reduce emissions and noise pollution.
Solution Approach 2:
The system changes the power source parameter dynamically based on availability and environmental conditions. By switching between different power sources (diesel, solar, grid), the system maintains refrigeration reliability while minimizing harmful emissions and noise by preferring cleaner sources when available.
2Object-generated harmful factors
If an electric TRU is utilized, then emissions and noise are reduced, but flexibility to add other power sources is lost
Solution Approach 1:
The power converter unit incorporates multiple input interfaces and conversion circuits that can accept various power sources including AC grid power, DC power sources, and solar panels. This universal design maintains the low-emission benefit of electric TRUs while restoring flexibility to incorporate multiple cleaner power sources.
Solution Approach 2:
The power conversion system is segmented into multiple independent conversion paths (AC to DC, DC to DC, solar input handling) that can operate independently or in parallel. This segmentation allows flexible addition of different power sources without compromising the electric TRU's emission reduction benefits.
3Ease of operation
If mechanical devices are used for part load operation, then compressor speed control is achieved, but efficiency decreases
Solution Approach 1:
The system replaces mechanical part-load control devices with an electronic power converter that uses electronic switching and PWM control to regulate compressor motor speed. This substitution eliminates the efficiency losses associated with mechanical control while maintaining ease of operation for part-load conditions.
Solution Approach 2:
The power converter provides dynamic speed control of the compressor motor by adjusting the electrical power output in real-time based on cooling load requirements. This dynamic electronic control achieves efficient part-load operation without the energy losses of mechanical control devices.
Data Source
AI summary
A trailer refrigeration unit is provided. Aspects include a plurality of power sources, wherein the plurality power sources are selectively coupled to a power converter and at least one compressor. The power converter is coupled to at least one fan and is selectively coupled to the at least one compressor. A microcontroller circuit is included and is configured to selectively operate the trailer refrigeration unit in one of a plurality of modes based on an environmental parameter within the trailer refrigeration unit. The plurality of modes includes a first mode where the at least one compressor and at least one fan are powered by the power converter and a second mode where the at least one compressor is powered by at least one of the plurality of power sources.