DC to DC converter sourcing variable DC link voltage
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Solution Overview
Problem
Existing DC to DC converters for HVACR systems face inefficiencies in powering variable speed electric machines, particularly at partial loads, due to limitations in generating multiple output voltages, which affects energy utilization and component longevity.
Innovation Solution
The implementation of a DC to DC boost converter system with multiple electromagnetic coils and a switch set that operates in different voltage states, allowing for the generation of multiple boosted voltages based on sensed load parameters, optimizing energy efficiency and extending component lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a typical boost converter is used to convert DC voltage, then the source voltage is boosted to a fixed output voltage, but the system cannot efficiently power variable speed electric machines at partial loads
Solution Approach 1:
The patent divides the single boost converter into multiple independent boost circuits (first boost circuit, second boost circuit, etc.), each capable of generating a specific output voltage. This segmentation allows the system to provide multiple output voltages (e.g., 300V, 400V, 500V) by selectively activating different boost circuits based on load requirements, thereby improving adaptability while managing complexity through modular design.
Solution Approach 2:
Each boost circuit is designed to perform the same voltage boosting function but with different output voltage characteristics. The system achieves multi-functionality by having multiple boost circuits that can be selectively activated, allowing a single converter system to serve multiple voltage requirements for variable speed electric machines at different load conditions.
2Loss of energy
If a fixed output voltage is used in the boost converter, then the converter structure is simple, but energy efficiency is reduced at partial loads
Solution Approach 1:
The patent implements dynamic voltage selection by enabling the controller to selectively activate different boost circuits based on real-time load conditions. When the electric machine operates at partial load, a lower output voltage boost circuit is activated to reduce energy losses. When full load is required, a higher voltage boost circuit is activated. This dynamic adaptation optimizes energy efficiency across different operating conditions while maintaining the necessary voltage adjustment capability.
3Productivity
If multiple boost circuits are implemented to provide multiple voltages, then energy efficiency improves, but the converter complexity increases
Solution Approach 1:
The patent combines multiple boost circuits into a single integrated converter system with a unified control architecture. The controller manages all boost circuits and selectively activates them based on load requirements. This merging approach allows the system to achieve high energy utilization efficiency through multiple voltage options while managing complexity through integration and centralized control, rather than having completely separate converter systems.
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 solution enhances electrical efficiency by providing variable boosted voltages to match the load requirements of variable speed electric machines, optimizing energy use and extending the life of components like DC link capacitors, while meeting emissions standards.
Implementation Method 1
a first boost circuit having a first electromagnetic coil; a second boost circuit having a second electromagnetic coil
Data Source
AI summary
An inverter-converter system includes a DC source, a DC to DC boost converter, a DC link capacitor, an inverter circuit, a variable speed electric machine, and a controller. The DC to DC boost converter receives an input DC voltage from the DC source. The inverter circuit converts the variable boosted voltage to an AC voltage to drive the variable speed electric machine. The controller senses a plurality of parameters from the variable speed electric machine, and controls the DC to DC boost converter to boost up the input DC voltage to a variable output voltage based on the plurality of parameters and/or the voltage (or load) needed by the variable speed electric machine. The design of the inverter-converter system can achieve an electrical efficiency and cost savings for the overall system.