Coordinating Control for Power Semiconductor Switching
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Solution Overview
Problem
High voltage and current power semiconductor switching devices face challenges in synchronized control due to noisy electrical environments, leading to a significant risk of device failure and cascading failures in systems where multiple devices are connected in series or parallel.
Innovation Solution
A coordinating control system that synchronizes the switching of multiple power semiconductor switching devices by controlling them through discrete states, including fully-off, saturated-on, and intermediate states, ensuring all devices reach a synchronized state before transitioning to the final state, using a central controller and sub-controllers with dedicated bus connections for efficient communication and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple power semiconductor switching devices are connected in series or parallel to operate at desired voltages and currents, then the system can handle high voltage and current loads, but the risk of device failure and cascading failures increases significantly due to noisy electrical environments
Solution Approach 1:
The control system segments the switching operation into multiple discrete intermediate states (e.g., partial conduction states) between fully-off and saturated-on. Each device transitions through these segmented states in a controlled sequence, allowing individual device monitoring and failure isolation without cascading effects to other devices in the system.
Solution Approach 2:
The coordinating control system implements feedback mechanisms to monitor the state of each switching device during transitions through intermediate states. This feedback allows the system to detect device anomalies early, adjust control signals accordingly, and prevent failure propagation across the system, thereby improving reliability while maintaining high power handling capability.
2Device complexity
If conventional switching control is used without intermediate states, then the control system is simpler, but synchronized switching of multiple devices is difficult to achieve in noisy electrical environments
Solution Approach 1:
The control system prepares devices for synchronized switching by first transitioning them to intermediate states where they are partially conductive. This preliminary action allows the system to establish synchronized timing and monitoring before committing to full switching operations, improving synchronization reliability without excessive complexity.
Solution Approach 2:
The coordinating control system acts as an intermediary between individual device controllers and the power switching devices. It manages the transition through intermediate states and coordinates the timing signals, providing a structured approach to synchronization that balances control complexity with reliable synchronized operation.
3Speed
If devices switch directly from fully-off to saturated-on states, then the switching speed is faster, but the current/voltage load is not balanced between devices and failure risk increases
Solution Approach 1:
The switching operation is divided into periodic phases: transition through intermediate states, brief pause for synchronization verification, and then final switching to saturated-on state. This periodic structure allows load balancing checks at each phase transition while maintaining overall fast switching performance through optimized phase durations.
Solution Approach 2:
The control system dynamically changes operating parameters during the switching process. Devices transition through intermediate conduction states with controlled current levels, allowing the system to balance load distribution across devices. The gate voltage and current parameters are adjusted progressively rather than abruptly, achieving both load balancing and acceptable switching speed.
Data Source
Figure 1~6a
Figure 2a
Figure 2b
AI summary
We describe a system for controlling very large numbers of power semiconductor switching devices (132) to switch in synchronisation. The devices are high power devices, for example carrying hundreds of amps and/or voltages of the order of kilovolts. In outline the system comprises a coordinating control system (110, 120), which communicates with a plurality of switching device controllers (130) to control the devices into a plurality of states including a fully-off state, a saturated-on state, and at least one intermediate state between the fully-off and saturated-on states, synchronising the devices in the at least one intermediate state during switching.