Distributed Inverter Harmonic Injection for Power Quality Control
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Solution Overview
Problem
Existing power networks with distributed energy resources and inverters face challenges in managing harmonic content, leading to issues like overheating, thermal tripping, and reduced power quality, as current harmonic filters are burdensome and inefficient.
Innovation Solution
A controller system identifies and coordinates distributed energy resources and inverter systems to inject constructive harmonic content, reducing destructive harmonic content without the need for additional harmonic filters by testing and optimizing the phase and amplitude of constructive harmonic injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If harmonic filters are used to reduce destructive harmonic content, then harmonic content is reduced, but power is wasted and system complexity increases
Solution Approach 1:
The patent converts the harmful harmonic content into beneficial constructive harmonics by injecting harmonics that are 180 degrees out of phase with the destructive harmonics. Instead of filtering out the harmful harmonics, the system uses the distributed inverter resources to generate counter-phase harmonics that cancel the destructive effects, thereby transforming the problem into a solution.
Solution Approach 2:
The patent enables distributed inverter systems to perform multiple functions: they continue to provide their primary power conversion function while simultaneously injecting constructive harmonics to reduce destructive harmonic content. This multi-functionality eliminates the need for separate harmonic filter devices, reducing system complexity and energy waste.
2Object-affected harmful factors
If harmonic filters are deployed at each load, then harmonic content is reduced, but device complexity and installation burden increase
Solution Approach 1:
The patent merges the harmonic reduction function into the existing distributed inverter systems rather than adding separate filter devices at each load. By combining multiple inverter resources into a coordinated harmonic injection system, the solution reduces the need for additional hardware and simplifies the overall system architecture.
Solution Approach 2:
The patent introduces a controller system as an intermediary that coordinates the harmonic injection from distributed inverters. This central controller manages the complex task of identifying destructive harmonics and directing counter-phase injection, thereby reducing the complexity burden from individual loads to a centralized management system.
3Object-affected harmful factors
If distributed inverter systems inject constructive harmonic content, then destructive harmonic content is reduced, but control complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the harmonic content in the power network, identifies destructive harmonics, and adjusts the injection of constructive harmonics from distributed inverters accordingly. This closed-loop control ensures that the system adapts to changing conditions while maintaining harmonic reduction effectiveness.
Solution Approach 2:
The patent performs preliminary identification and coordination of distributed inverter resources before harmonic reduction is needed. The controller system pre-establishes communication channels and capability assessments with potential inverter participants, so that when harmonic reduction is required, the system can quickly deploy the appropriate resources without extensive real-time coordination overhead.
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
Effectively reduces destructive harmonic content while optimizing resource usage, avoiding the need for additional wiring and load restrictions, thus enhancing power quality and system efficiency.
Implementation Method 1
inverter systems coupled to the distributed energy resources and configured to transform between direct current (DC) energy and alternating current (AC) energy bidirectionally between the distributed energy resources and the grid
Implementation Method 2
the injected constructive harmonic content includes at least a portion of the destructive harmonic content 180 degrees out of phase
Data Source
AI summary
A controller system reduces destructive harmonic content within a power network system, the power network system comprising one or more distributed energy resources, one or more distributed inverter systems, one or more nonlinear loads, and a bus coupling the one or more distributed energy resources to the one or more nonlinear loads. The controller system comprises one or more sensors; one or more hardware processors; and memory storing computer instructions, the computer instructions when executed by the one or more hardware processors configured to perform receiving, by the one or more sensors, sensor data indicative of destructive harmonic content of a particular order on the bus; and using a particular distributed energy resource and a particular distributed inverter system to inject constructive harmonic content to reduce the destructive harmonic content.