Variable DC-Link Boost Converter for Partial-Load Efficiency
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Solution Overview
Problem
Existing HVAC systems face inefficiencies in powering variable speed electric machines due to the limitations of single-output voltage boost converters, which result in suboptimal performance and increased energy losses, especially at partial loads.
Innovation Solution
The implementation of a DC to DC boost converter system with multiple tapped winding electromagnetic coils and a controller that adjusts switch configurations to generate variable boosted voltages based on sensed load parameters, optimizing inductance and reducing power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single-output voltage boost converter is used, then the device complexity is reduced, but the energy efficiency deteriorates at partial loads
Solution Approach 1:
The patent implements a dynamic voltage selection mechanism where the controller automatically switches between first and second boosted voltages based on real-time load detection. This dynamic adaptation allows the system to operate at optimal efficiency points across varying load conditions, resolving the contradiction between maintaining simple converter structure and achieving high energy efficiency at partial loads.
Solution Approach 2:
The system changes the output voltage parameter from a fixed single value to a variable parameter that can take on two distinct values (first boosted voltage and second boosted voltage). This parameter change enables the converter to adapt its operating point to match load requirements, thereby improving energy efficiency without significantly increasing device complexity.
2Adaptability or versatility
If multiple boosted voltages are sourced, then the adaptability to different load conditions is improved, but the device complexity increases
Solution Approach 1:
The boost converter is designed to perform multiple functions by providing two distinct boosted voltages from a single converter unit. The controller enables the same hardware to adapt to different load conditions by switching between voltage levels, achieving multi-functionality without requiring separate converters for each voltage level, thus improving adaptability while controlling complexity.
Solution Approach 2:
The system employs dynamic voltage switching controlled by a controller that detects load conditions in real-time. This dynamic control mechanism allows the converter to adapt its output voltage based on actual load requirements, achieving high adaptability through software/control logic rather than through complex hardware reconfiguration.
3Productivity
If variable speed operation is enabled, then the productivity of the HVAC system is improved, but the energy loss increases without optimized voltage control
Solution Approach 1:
The controller implements a feedback mechanism that continuously monitors the load on the variable speed electric machine and uses this information to determine the appropriate boosted voltage level. This feedback loop ensures that the system maintains optimal efficiency by matching the output voltage to the actual load requirements, thereby improving productivity while minimizing energy losses that would otherwise occur with fixed voltage operation.
Solution Approach 2:
The system dynamically changes the output voltage parameter based on detected load conditions, switching between first and second boosted voltages. This parameter adaptation allows the variable speed electric machine to operate efficiently across its full speed range, improving overall system productivity while preventing the energy losses that would result from mismatched voltage-speed combinations.
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 approach enhances electrical efficiency, extends component lifespan, and optimizes energy usage, particularly at partial loads, while meeting emissions standards and improving system performance.
Implementation Method 1
A typical switch-mode boost converter includes an inductor, a switch, and a flywheel diode
Implementation Method 2
The switch can be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET)
Implementation Method 3
The flywheel diode can be replaced by a MOSFET
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.