Cascading AC Voltage Regulator for Fine Micro-Stepping Control
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Solution Overview
Problem
Conventional tap changing regulators suffer from limited regulation granularity, slow response, and inefficiencies due to the need for multiple taps and switches, which results in coarse voltage regulation, power quality issues, and high power dissipation, especially when integrating Distributed Energy Resources (DER) and managing AC waveforms.
Innovation Solution
A novel tap changing regulator topology that uses a combination of transformer voltage taps and switches in unique configurations, along with a commutation method that eliminates the need for voltage clamps or snubbers, allowing for a greater number of micro-steps within a given voltage range with fewer taps and switches, achieving a ratio of steps to switches or taps greater than unity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional tap changing regulators use multiple taps and switches to achieve fine voltage regulation, then regulation granularity is improved, but device complexity and power dissipation increase
Solution Approach 1:
The patent divides the voltage regulation function into multiple stages, where each stage has fewer taps and switches that work together to achieve fine-grained voltage control. The first stage provides coarse regulation with fewer steps, while the second stage provides fine regulation with smaller steps, eliminating the need for a single complex stage with many taps and switches.
Solution Approach 2:
The patent transitions from a single-dimension approach (one long list of taps and switches) to a multi-dimensional approach (multiple stages with hierarchical regulation). The first stage handles large voltage adjustments while the second stage handles fine adjustments, creating a two-dimensional regulation space that reduces the total number of required components.
2Device complexity
If mechanical tap changers are used to reduce the number of taps, then device complexity is reduced, but response speed deteriorates
Solution Approach 1:
The patent segments the regulation function into two stages: the first stage uses a mechanical tap changer with fewer taps for coarse regulation, while the second stage uses electronic switches for fine regulation. This segmentation allows the mechanical component to operate at lower complexity while the electronic component provides fast response for precise control.
Solution Approach 2:
The patent replaces mechanical switching in the second stage with electronic switching (using IGBTs or MOSFETs), which provides much faster response speed. The mechanical tap changer is retained only for the first stage where slower response is acceptable, combining the advantages of both mechanical and electronic systems.
3Speed
If electronic switches are used to achieve fast response and fine regulation, then response speed and regulation precision are improved, but power dissipation and cost increase
Solution Approach 1:
The patent segments the regulation function so that the first stage (coarse regulation) uses mechanical tap changers with lower power dissipation, while the second stage (fine regulation) uses electronic switches. This segmentation ensures that electronic switches are used only when necessary for precise control, minimizing overall power dissipation while maintaining fast response where needed.
Solution Approach 2:
The patent applies electronic switching partially, only in the second stage for fine regulation, rather than using it for all regulation steps. This partial application of electronic switching provides fast response and fine granularity where necessary while avoiding the excessive power dissipation that would result from using electronic switches for all voltage adjustments.
4Device complexity
If coarse voltage regulation steps are used, then device complexity is reduced, but power quality and waveform control deteriorate
Solution Approach 1:
The patent segments the regulation process into two stages: the first stage provides coarse regulation with larger steps, and the second stage provides fine regulation with smaller steps. This segmentation allows coarse regulation to handle major voltage adjustments while fine regulation eliminates large step changes that cause power quality issues, maintaining both simplicity and power quality.
Solution Approach 2:
The patent adds a second dimension to the regulation process by introducing a hierarchical two-stage structure. The first dimension (first stage) handles coarse regulation, while the second dimension (second stage) handles fine regulation, creating a multi-layered approach that resolves the conflict between simplicity and power quality.
Data Source
AI summary
A tap changing regulator with at least one regulator stage that has a set of input taps and a set of switches in a switching matrix. The have respective on-off modes to connect one or more of the taps to an output voltage to effect a number of regulation steps, where the ratio of the number of regulation steps to the number of taps is always greater than 1:1. The regulator taps are spaced between sets of windings having a progressive windings ratio of 1 to 3 to 2, or integer multiples of that ratio. Series connected additional regulator stages have an input tap with a windings ratio that is twice the sum of the first stage regulation steps, plus 1.