Virtual Multi-Shaft Controller for Power Converter Stability
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Solution Overview
Problem
Existing methods for controlling power converters in interconnected power systems fail to effectively coordinate the control actions of multiple virtual synchronous machines (VRCs) to improve dynamic stability and power flow, leading to potential instabilities and instability risks during disturbances.
Innovation Solution
A Virtual Multi-Shaft (VMS) controller that emulates mechanical shafts between power converters using digital models to coordinate active power exchanges, adjusting system parameters in real-time to enhance damping and stability by mimicking the natural power exchange between coupled masses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power converters are interconnected through power electronics-based active systems to increase capacity and flexibility, then the power transmission capability and optimization of power flows are improved, but dynamic stability and system coherence deteriorate due to lack of coordination between converters
Solution Approach 1:
The patent introduces a central coordinator that acts as an intermediary between multiple power converters. This coordinator schedules and coordinates the control actions of converters, enabling them to exchange active power in a coordinated manner that maintains dynamic stability while achieving high power transmission capability. The coordinator mediates between the individual converters to prevent instability caused by uncoordinated control actions.
2Adaptability or versatility
If multiple virtual synchronous machines operate independently to provide flexibility, then individual converter control autonomy is improved, but system-wide coordination and damping capability worsen due to lack of coherent response
Solution Approach 1:
The patent segments the control function into two parts: individual converter control (maintaining autonomy) and central coordination (ensuring system-wide coordination). Each converter maintains its own control capabilities while the central coordinator schedules their interactions. This segmentation allows converters to operate autonomously while achieving coherent system-wide response through coordinated scheduling.
Solution Approach 2:
The patent merges independent converter control with central coordination to achieve both autonomy and coherence. The control system combines local converter decisions with global scheduling information, allowing converters to maintain their autonomous operation while being coordinated by the central system to provide unified damping capability and coherent response to disturbances.
3Ease of operation
If traditional control methods are used without coordination, then implementation simplicity is maintained, but power flow optimization and stability enhancement capability are lost
Solution Approach 1:
The central coordinator serves as an intermediary that adds coordination capability without requiring complex modifications to individual converter control structures. The coordinator handles the scheduling and coordination logic, allowing converters to maintain relatively simple control implementations while achieving enhanced stability through coordinated operation.
Data Source
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AI summary
The invention provides a control method and system for power converters that are electrically interconnected through a power grid. The control mechanism uses a digital model of a mechanical shaft for emulating the electrical coupling between each pair of power converters. Power transfers computed using this multi-shaft model are applied at the corresponding power converters, which results in stable and disturbance-resilient power signals throughout the power network.