Unidirectional AC-DC Supply for Predictable Grid-Connected Local Power
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Solution Overview
Problem
Smart inverters, certified under UL1741 SA standards, are capacity limited and congested when producing reactive power for the electric utility grid, leading to unpredictable energy delivery from local renewable sources to the grid, impacting flexibility in energy storage and generation, and affecting grid stability as more renewables are deployed.
Innovation Solution
A power system that operates independently of the electric utility grid using a unidirectional AC-to-DC power supply, allowing energy flow only from the AC side to the DC side, eliminating the need for smart inverters and enabling optimal energy production and usage without impacting grid stability, by prioritizing local energy sources and utility power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If smart inverters are used to support electric utility grid stability by producing reactive power, then grid stability is improved, but the amount of real power the inverter can provide to local load is reduced
Solution Approach 1:
The patent divides the inverter's power delivery function into two separate devices: a smart inverter dedicated to grid support functions (reactive power, frequency regulation) and a unidirectional power supply dedicated to local load power delivery. This segmentation eliminates the capacity conflict by assigning different functional responsibilities to separate devices, allowing the smart inverter to fully support grid stability while the unidirectional power supply provides real power to local loads without capacity limitations from reactive power production.
2Adaptability or versatility
If smart inverters are used to meet electric utility grid demands for reactive power, then grid support capability is improved, but the inverter becomes congested and real power delivery to local load is limited
Solution Approach 1:
The patent segments the power conversion system into two independent devices: a smart inverter that adapts to grid support needs (reactive power, voltage regulation, frequency control) and a unidirectional power supply that maximizes real power delivery to local loads. This segmentation allows each device to operate at full capacity for its designated function without congestion, as the unidirectional power supply is not constrained by reactive power production requirements.
Solution Approach 2:
The smart inverter is designed with multi-functionality to handle various grid support tasks (reactive power compensation, voltage regulation, frequency control, harmonic filtering), while the unidirectional power supply provides universal real power delivery to local loads. This multi-functional design allows the smart inverter to adapt to different grid conditions and requirements without compromising real power delivery, as that function is handled by the dedicated unidirectional power supply.
3Adaptability or versatility
If local energy producers are tied to the grid through smart inverters, then grid integration is improved, but control and predictability of power delivery to the grid is reduced
Solution Approach 1:
The patent segments the grid connection function from the local power delivery function. The smart inverter handles grid integration, synchronization, and compliance with utility interconnection standards, while the unidirectional power supply handles local power delivery with full user control. This segmentation allows local energy producers to maintain predictability and control over their power delivery to local loads, as the unidirectional power supply operates independently of grid conditions that would otherwise constrain smart inverter-based systems.
4Productivity
If more renewable energy is deployed to the electric utility grid, then renewable energy penetration is improved, but grid stability is affected requiring additional smart inverter support
Solution Approach 1:
The patent segments the renewable energy system into a smart inverter component for grid stability support and a unidirectional power supply component for local power delivery. This segmentation allows renewable energy systems to increase penetration and production without proportionally increasing the burden on smart inverters for stability support, as the unidirectional power supply handles local load demands independently, freeing the smart inverter to focus exclusively on grid stability functions.
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 allows for predictable and flexible energy delivery from local sources to the grid, maintaining grid stability while optimizing energy usage, and reducing the complexity of interconnection agreements and compliance with utility standards.
Implementation Method 1
a unidirectional AC-to-DC power supply electrically interposed between the electric utility grid and the local bus, the power supply having an AC side and a DC side, wherein the power supply is configured to allow energy flow only from the AC side to the DC side
Data Source
AI summary
A power system connectable to an electric utility grid includes a local bus connected to at least one non-grid source of electrical energy; an electrical connection between the local bus and an electric utility grid; and a unidirectional AC-to-DC power supply electrically interposed between the electric utility grid and the local bus, the power supply having an AC side and a DC side, wherein the power supply is configured to allow energy flow only from the AC side to the DC side.