Grid-Synchronizing Inverter Control With Virtual Inertia Loops
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Solution Overview
Problem
Inverter-based power supplies, which are not rotating machine based, lack automatic synchronization capabilities with the power grid and other power supplies in terms of droop, phase, inertia, voltage magnitude, and frequency, making seamless disconnection and reconnection challenging.
Innovation Solution
An apparatus and method for controlling inverters, incorporating controllers with droop control, virtual inertia control, and voltage control loops, enabling synchronization with the power grid and other power supplies by providing droop, phase, frequency, and inertia control, effectively acting as a synchronous machine emulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inverter-based power supplies are used, then efficiency and adaptability are improved, but automatic synchronization capability with the power grid deteriorates
Solution Approach 1:
The patent introduces a controller as an intermediary device between the inverter-based power supply and the power grid. This controller implements droop control, virtual inertia control, and voltage control loops to mediate the interaction, enabling the inverter to synchronize with the grid without requiring rotating machinery. The controller translates grid conditions into appropriate inverter responses, resolving the synchronization deficit while maintaining inverter efficiency.
Solution Approach 2:
The patent replaces the mechanical synchronization capability of rotating machines with an electronic control system. By using controllers that implement droop control, virtual inertia control, and voltage control loops, the system substitutes mechanical inertia and synchronization mechanisms with electronic algorithms, allowing inverter-based power supplies to achieve grid synchronization without rotating components.
2Reliability
If seamless disconnection and reconnection is achieved, then reliability is improved, but control complexity increases
Solution Approach 1:
The patent implements preliminary synchronization actions through droop control and virtual inertia control before actual grid connection. The controller pre-adjusts voltage magnitude, frequency, and phase angle based on anticipated grid conditions, enabling seamless disconnection and reconnection. This preliminary preparation reduces the complexity of real-time control during transition events.
Solution Approach 2:
The patent employs multiple feedback control loops including droop control loop, virtual inertia control loop, and voltage control loop. These loops continuously monitor system parameters and adjust inverter output accordingly, enabling seamless disconnection and reconnection. The feedback mechanisms automate the control process, reducing manual intervention complexity while ensuring reliable operation.
Data Source
AI summary
An example apparatus for controlling one or more inverters is provided herein. In some embodiments, the apparatus for controlling one or more inverters may include one or more controllers. In some embodiments, each of the one or more inverters is associated with at least one power source. In some embodiments, each of the one or more controllers may configured to provide droop control, voltage magnitude control, phase control, frequency control and inertia control for an associated inverter of the one or more inverters. In some embodiments, each of the one or more controllers comprises a voltage control loop, a virtual inertia control loop, and a droop control loop enabling the power supplies to sync with a power grid and/or other power supplies when the power supply is disconnected from the power grid and/or other power supplies and/or connected to a power supply to the power grid and/or other power supplies.