Isolated Voltage Optimization Module for Fast Grid-Edge Sag Control
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Solution Overview
Problem
Conventional solutions for precise voltage control at the grid edge face challenges such as slow response, high losses, and high costs, especially in reducing energy consumption and peak demand, while maintaining voltage within allowed ANSI bands and handling voltage sags, which are not efficiently addressed by existing technologies.
Innovation Solution
The stackable isolated voltage optimization module (SIVOM) uses a transformer with a switching circuit and controller to dynamically adjust voltage and phase angle, providing +/-5% voltage control and +/-6° phase angle adjustment, with a compact, passive cooling design suitable for high-power applications, scalable from 1MW to 20MW, and capable of handling short circuit currents up to 50kA, with a fail-normal architecture and communication-enabled integration with grid ancillary markets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If transformers with tapped windings using electromechanical switching are used for voltage control, then voltage regulation can be achieved, but response speed is slow and switching contact life is limited
Solution Approach 1:
The patent replaces electromechanical switching with solid-state power electronic switches (IGBTs or MOSFETs) in a bridge circuit configuration. This substitution eliminates mechanical moving parts, providing instantaneous response speed while ensuring long operational life without contact wear, directly resolving the contradiction between response speed and reliability.
2Measurement precision
If series connected transformers are used to inject voltage for precise regulation, then precise voltage control can be achieved, but grid faults cause high short circuit currents that impress high stress on the series transformer making design challenging and expensive
Solution Approach 1:
The patent introduces a bridge circuit with power electronic switches as an intermediary between the voltage source and the load. This intermediary provides precise voltage control through controlled switching and simultaneously limits short circuit currents through the inherent impedance of the bridge circuit and controlled switching sequences, resolving the contradiction between control precision and stress resistance.
3Adaptability or versatility
If shunt VAR sources are used for voltage control, then local voltage control can be provided, but the level of control is limited and not dispatchable as it depends on load current, power factor, service transformer impedance and injected VARs
Solution Approach 1:
The patent employs a dynamic bridge circuit with controllable power electronic switches that can independently adjust voltage magnitude and phase angle. This dynamic control mechanism is not dependent on load conditions or transformer parameters, providing fully dispatchable voltage control that adapts to any grid condition, resolving the contradiction between adaptability and control complexity.
4Loss of energy
If conventional voltage control solutions are used, then voltage regulation can be achieved, but energy consumption is high and losses are significant
Solution Approach 1:
The patent uses periodic pulse-width modulation (PWM) switching of power electronic devices to control voltage. This periodic switching action allows precise control of power transfer with minimal losses, as the switches operate in their high-efficiency switching mode rather than continuous linear regulation, significantly reducing energy losses while maintaining effective voltage control.
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
The SIVOM achieves sub-cycle response to voltage sags, reduces energy consumption by 5-7%, minimizes losses to less than 0.3%, and provides rapid resilience against voltage fluctuations, enabling efficient energy management and peak demand reduction while maintaining high reliability and flexibility in industrial and utility applications.
Implementation Method 1
a transformer having a turns ratio between a primary winding and a secondary winding of the transformer
Data Source
Figure 1
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Figure 3A
AI summary
Various examples are provided for isolated voltage optimization and control. In one example, a stackable isolated voltage optimization module (SIVOM) includes a transformer having a turns ratio between a primary winding and a secondary winding; a switching circuit configured to energize the secondary winding with a voltage provided from the three-phase power system or short the secondary winding; and a connection block configured to couple the switching circuitry to the first phase and a neutral, or to second and third phases of the three-phase power system. In another example, a system includes a SIVOM coupled to each phase of a three-phase power system, where each SIVOM comprises: a transformer and a switching circuit configured to boost or buck a voltage or change a phase angle of the phase coupled to that SIVOM by energizing a secondary winding of the transformer with a voltage provided from the three-phase power system.