Series-Connected Switching Voltage Balancing With EES Timing
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Solution Overview
Problem
Semiconductor-based switching devices connected in series face challenges in maintaining equal voltage during switching transients due to delays, parameter differences, and parasitic elements, leading to potential voltage imbalances over time.
Innovation Solution
The apparatus incorporates switching device voltage balancing circuits (VBCs) with electrical energy storage modules and a control module that adjusts switching timing and charging/discharging to equalize voltages across series-connected switching devices, using resistive circuitry to manage voltage thresholds and prevent overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If semiconductor-based switching devices are connected in series to facilitate standardized solution and high-power capability, then power capacity and reliability are improved, but voltage sharing balance deteriorates during switching transients
Solution Approach 1:
The patent applies preliminary action by pre-charging or pre-discharging the EES modules before the main switching event. The control module adjusts the timing of charging/discharging operations in advance of the switching transient, ensuring that voltage balance is established before the critical switching moment occurs. This prevents voltage divergence by preparing the voltage balancing circuits proactively rather than reacting after imbalance occurs.
Solution Approach 2:
The patent implements feedback through the control module that continuously monitors the voltage across each switching device and dynamically adjusts the charging/discharging timing of the corresponding EES module. The control module obtains voltage values and uses this feedback information to control the timing of switching and EES operations, creating a closed-loop system that actively maintains voltage balance despite variations in device characteristics or switching delays.
2Stability of the object's composition
If very fast dynamic feedback systems are employed to address voltage sharing issues, then voltage balance is improved, but system complexity and reliability deteriorate
Solution Approach 1:
Instead of relying on fast feedback during the transient, the patent uses preliminary action by pre-adjusting the EES module voltages before switching. This approach achieves voltage balance without requiring complex real-time feedback systems during the critical transient period, thereby reducing system complexity while maintaining effectiveness.
Solution Approach 2:
The patent introduces EES modules as intermediary elements between the switching devices and the voltage balancing control. These EES modules act as buffers that can be independently charged or discharged to compensate for voltage imbalances, simplifying the control architecture compared to direct fast feedback on the switching devices themselves.
3Stability of the object's composition
If switching timing is adjusted to compensate for voltage imbalance, then voltage distribution is improved, but control complexity increases
Solution Approach 1:
The patent changes the timing parameter of EES charging/discharging operations to compensate for voltage imbalances. By adjusting when the EES modules are charged or discharged rather than changing the switching device timing directly, the control complexity is reduced while still achieving the desired voltage distribution across the series-connected devices.
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
This solution effectively balances voltages across series-connected switching devices during and after switching, reducing the risk of voltage divergence and ensuring equal voltage distribution, even in the presence of delays and parameter variations, and is scalable for various configurations.
Implementation Method 1
Each of the plurality of switching device VBCs comprises an electrical energy storage (EES) module which can be (e.g., controllably) charged or discharged
Implementation Method 2
using resistive circuitry to manage voltage thresholds and prevent overvoltage
Data Source
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AI summary
An apparatus (100) is disclosed, comprising a plurality of interconnected switching devices (1, 2), at least two of which are connected in series so as to form at least one series-connection of switching devices (1, 2; 18, 19), and a plurality of switching device voltage balancing circuits, VBCs, (3, 4) for balancing of voltages over the switching devices of the at least one series-connection of switching devices during and after switching the switching devices from a first operational state to a second operational state. Each of the plurality of switching device VBCs (3, 4) comprises an electrical energy storage, EES, module (6, 7) which can be controllably charged or discharged. Each of the plurality of switching device VBCs (3, 4) corresponds to a respective switching device (1, 2) of the at least one series-connection of switching devices (1, 2). For each series-connection of switching devices, timing of switching the switching devices (1, 2) of the series-connection of switching devices between the operational states in relation to each other and/or timing of charging and/or discharging the EES modules (6, 7) of the respective ones of the switching device VBCs (3, 4) corresponding to the switching devices (1, 2) of the series connection of switching devices is/are controlled based on one or more values indicative of the voltage of each of the EES modules (6, 7) such that any differences between the voltages of the EES modules (6, 7) are decreased.