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 converter is divided into multiple independent boost circuits (first boost circuit, second boost circuit, third boost circuit), each capable of generating a specific output voltage. This segmentation allows the system to provide multiple discrete voltage levels (e.g., 300V, 400V, 500V) by activating only the necessary circuits, thereby achieving adaptability while maintaining manageable complexity through modular design.
Solution Approach 2:
Each boost circuit is designed to perform the same voltage boosting function but at different output voltage levels. The circuits share common components such as the DC source, control unit, and electromagnetic coil structure, allowing a single converter system to universally serve multiple voltage requirements for variable speed electric machines across different load conditions.
2Loss of energy
If multiple boost circuits are implemented to provide multiple voltages, then energy efficiency at partial loads is improved, but the device complexity increases
Solution Approach 1:
The control unit dynamically selects and activates only the necessary boost circuit(s) based on the real-time load requirements and desired output voltage. This dynamic operation ensures that energy is efficiently utilized by avoiding unnecessary voltage conversion stages, thereby reducing energy losses while managing device complexity through intelligent control rather than permanent hardware multiplication.
Solution Approach 2:
Multiple boost circuits are merged into a single integrated converter system with shared components including the DC source, control unit, and electromagnetic coil architecture. This merging approach allows the system to achieve multiple voltage outputs without proportionally increasing overall complexity, as common components serve all circuits.
3Duration of action of stationary object
If a single output voltage is used, then the converter structure is simple, but the DC link capacitor lifespan is reduced due to inefficient operation at partial loads
Solution Approach 1:
The system changes the output voltage parameter dynamically by selecting different boost circuits based on load requirements. This parameter adaptation allows the DC link capacitor to operate within optimal voltage ranges, avoiding excessive voltage stress that would occur with a single high-voltage output, thereby extending capacitor lifespan while managing complexity through controlled parameter variation.
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.