Bidirectional DC-AC Power Converter with High-Frequency Transformer
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Solution Overview
Problem
Existing DC-AC power conversion systems in uninterruptible power supplies (UPS) face inefficiencies due to the use of bulky low-frequency transformers and high complexity, requiring many high-voltage switches and additional components, which increase manufacturing costs and reduce power conversion efficiency.
Innovation Solution
A bi-directional power converter with a high-frequency transformer and selectively configurable circuitry that operates in both inverter and charger modes using a single power conversion channel, minimizing the number of high-voltage components and utilizing shared components to achieve high power conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a low-frequency transformer is used to step up battery voltage and provide isolation, then voltage transformation and isolation are achieved, but the transformer becomes bulky, heavy, and power conversion efficiency deteriorates
Solution Approach 1:
The patent changes the operating frequency parameter from low-frequency (50/60 Hz) to high-frequency operation. This allows the transformer to be much smaller and lighter while maintaining the same power transformation capability, and simultaneously improves power conversion efficiency due to reduced core losses and smaller magnetic components.
Solution Approach 2:
The patent employs high-frequency switching of power electronic devices to generate high-frequency AC signals that drive the transformer. This high-frequency excitation enables the transformer to operate efficiently at reduced size while maintaining voltage transformation and isolation functions.
2Adaptability or versatility
If a high-frequency transformer is used with separate power conversion channels for inverter and charger, then bidirectional power conversion is achieved, but the number of high-voltage switches and components increases, raising manufacturing costs
Solution Approach 1:
The patent designs a single power conversion channel that can operate in both inverter mode (converting DC from battery to AC for load) and charger mode (converting AC from mains to DC for battery charging). The same high-frequency transformer, switching devices, and control circuitry are used bidirectionally, eliminating the need for separate conversion channels and reducing component count.
Solution Approach 2:
The patent merges the inverter and charger functions into a single integrated power conversion channel. The high-frequency transformer and switching network are configured to perform both power conversion directions using the same components, thereby reducing the total number of high-voltage switches and other components required.
3Power
If many high-voltage switches and additional components are used to support load reactive power and large current, then power conversion capability is improved, but manufacturing costs increase and power conversion efficiency decreases
Solution Approach 1:
The patent uses high-frequency operation to reduce the stress and current requirements on individual switching devices. By operating at high frequency, the same power capability is achieved with fewer and smaller components, reducing manufacturing cost while maintaining power conversion capability.
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
The solution achieves high power conversion efficiency, reduces component utilization inefficiencies, and lowers manufacturing costs by using a simplified control device and shared components across multiple operating modes, while minimizing energy wastage and thermal stress.
Implementation Method 1
a transformer, a first connection node switchably connected to the power line in the second interconnection configuration and switchably connected to the transformer in the first interconnection configuration
Data Source
Figure 1
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Figure 3A
AI summary
A power converter includes a power input configured to receive input power from an AC power source, a power output configured to provide output power to a load, a battery interface configured to exchange DC power with a battery, and power converter circuitry. The power converter circuitry is adapted to, in a first interconnection configuration, convert the input power into the DC power at the battery interface, and, in a second interconnection configuration, convert the DC power at the battery interface into the output power. The power converter circuitry has a power line, a transformer, a first connection node switchably connected to the power line in the first interconnection configuration and switchably connected to the transformer in the second interconnection configuration, and a second connection node switchably connected to the transformer in the first interconnection configuration and switchably connected to the power line in the second interconnection configuration.