UPS DC Bus Control for Renewable Power Integration
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Solution Overview
Problem
Conventional uninterruptible power supplies (UPS) face inefficiencies when utilizing renewable energy sources due to the intermittent nature of these sources and the need for multiple power conversion stages, which increases energy loss and reduces efficiency in powering critical loads.
Innovation Solution
A power supply system that integrates a renewable power source, a DC bus, and a controller to monitor and manage power from both AC and renewable sources, optimizing power distribution by reducing the number of conversion stages through direct power provision to the DC bus or battery, and using energy storage to supplement power when necessary, thereby minimizing grid dependency and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If multiple power conversion stages are used to integrate renewable energy sources with conventional UPS, then the system can utilize renewable energy, but energy loss increases and efficiency decreases
Solution Approach 1:
The patent combines the renewable energy integration function directly into the UPS power conversion path by coupling the DC/DC converter to the DC bus, eliminating separate conversion stages. This merging of functions reduces the number of power conversion steps and associated energy losses while maintaining the ability to utilize renewable energy sources.
Solution Approach 2:
The DC/DC converter is designed to operate in multiple modes: it can convert renewable DC power to charge the battery or directly supply the load, and it can also function as a standard UPS converter when renewable power is unavailable. This multi-functionality eliminates the need for separate dedicated renewable energy conversion equipment, reducing overall system energy losses.
2Use of energy by stationary object
If renewable power sources are integrated into the UPS system, then energy costs are reduced, but the system complexity increases
Solution Approach 1:
The DC/DC converter serves multiple functions within the UPS system: it converts renewable DC power to appropriate voltage levels, charges the battery when excess renewable power is available, and can supply power directly to the load. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in system complexity while achieving energy cost reduction.
Solution Approach 2:
The controller automatically manages the integration of renewable power sources by monitoring power availability and system state, making decisions about charging the battery or supplying the load without external intervention. This self-service capability simplifies the user interface while handling the complexity of renewable energy integration internally.
3Productivity
If the DC/DC converter operates without monitoring output power capability, then the system is simpler, but power distribution efficiency decreases
Solution Approach 1:
The controller continuously monitors the output power capability of the renewable power source and uses this feedback information to adjust the operation of the DC/DC converter. This feedback mechanism ensures that the converter operates within the capabilities of the renewable source, optimizing power distribution efficiency while managing the complexity through automated control rather than manual intervention.
Solution Approach 2:
The DC/DC converter operation is dynamically adjusted based on real-time monitoring of the renewable power source's output capability. The converter can change its operating mode (charging battery vs. supplying load) based on current conditions, allowing the system to optimize power distribution efficiency in response to varying renewable energy availability without requiring complex fixed infrastructure.
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 improves the utilization of renewable energy by reducing energy losses and enhancing the efficiency of power delivery to critical loads, while also reducing energy costs associated with grid power usage.
Implementation Method 1
a first DC/DC converter coupled between the renewable power source and the DC bus and configured to provide DC power derived from the renewable power source to the DC bus
Implementation Method 2
a converter coupled to the input, an inverter coupled to the output, and a DC bus coupled between the converter and the inverter
Implementation Method 3
an inverter coupled to the output, and a DC bus coupled between the converter and the inverter
Implementation Method 4
the controller is configured to monitor a charge level of the energy storage device, to determine that the energy storage device is at least partially uncharged and that DC power from the renewable power source is unavailable
Data Source
AI summary
A power supply system including an uninterruptible power supply (UPS) comprising an input coupled to an AC source and configured to receive input AC power from the AC source and an output configured to provide AC output power to a load, the UPS including a converter coupled to the input, an inverter coupled to the output, and a DC bus coupled between the converter and the inverter, a renewable power source configured to provide DC power derived from a renewable energy source, a first DC/DC converter coupled between the renewable power source and the DC bus and configured to provide DC power derived from the renewable power source to the DC bus, and a controller in communication with the first DC/DC converter and configured to monitor an output power capability of the renewable power source, and to operate the first DC/DC converter to provide DC power derived from the renewable power source to the DC bus based on the output power capability of the renewable power source.