Semiconductor Automatic Transfer Switch for High-Current Reliability
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Solution Overview
Problem
Automatic transfer switches using relays face issues with slow switching times and reliability at high currents, leading to potential damage and switching failures due to mechanical limitations and the inability to withstand instantaneous large currents.
Innovation Solution
The power supply system incorporates two switch apparatuses for each power source, each comprising a relay switch, a bypass switch, a semi-controllable switch, and a fully-controllable switch, with a control unit managing the switches to ensure seamless transitions between power sources, utilizing fully-controllable semiconductor switches like IGBTs or MOSFETs for improved control and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If relay switches are used for automatic transfer switching, then the system can provide simple and reliable power source switching, but the switching time becomes slow and the reliability deteriorates at high currents due to mechanical limitations and electric arc damage
Solution Approach 1:
The patent replaces mechanical relay switches with semiconductor switches (IGBTs or MOSFETs) that have no moving parts. This substitution eliminates mechanical wear and contact arc damage, enabling instantaneous switching responses while maintaining high reliability under large currents. The semiconductor switches are controlled by gate signals to achieve rapid power source transitions without mechanical limitations.
Solution Approach 2:
The patent introduces a control unit as an intermediary between the power sources and load. This control unit coordinates the switching operations of multiple semiconductor switches, ensuring proper sequencing and preventing simultaneous connections that could cause short circuits. The control unit manages the transition process to maintain system reliability during switching operations.
2Device complexity
If relay switches are used for automatic transfer switching, then the system structure remains simple, but the reliability deteriorates due to contact damage from electric arcs and switching failures after multiple operations
Solution Approach 1:
The patent replaces mechanical relay switches with semiconductor switches (IGBTs or MOSFETs) that have no moving parts. This substitution eliminates mechanical wear and contact arc damage, enabling instantaneous switching responses while maintaining high reliability under large currents. The semiconductor switches are controlled by gate signals to achieve rapid power source transitions without mechanical limitations.
Solution Approach 2:
The patent introduces a control unit as an intermediary between the power sources and load. This control unit coordinates the switching operations of multiple semiconductor switches, ensuring proper sequencing and preventing simultaneous connections that could cause short circuits. The control unit manages the transition process to maintain system reliability during switching operations.
3Reliability
If SCR is used to replace relay switches, then the ability to withstand instantaneous large currents improves and mechanical life limits are eliminated, but the switching control capability deteriorates because SCR cannot be turned off by external control signals
Solution Approach 1:
The patent changes the control parameter mechanism from SCR's latching characteristic to fully controllable semiconductor switches (IGBTs/MOSFETs) that respond to gate signals. These switches can be turned on and off by external control signals, providing bidirectional control capability. The gate control mechanism allows precise timing and sequencing of switch operations, enabling reliable automatic transfer switching with full controllability.
4Extent of automation
If relay switches are used for power source switching, then the system can operate with simpler control logic, but the productivity deteriorates due to slow switching time affecting power supply continuity
Solution Approach 1:
The patent replaces mechanical relay switches with semiconductor switches (IGBTs or MOSFETs) that have no moving parts. This substitution eliminates mechanical wear and contact arc damage, enabling instantaneous switching responses while maintaining high reliability under large currents. The semiconductor switches are controlled by gate signals to achieve rapid power source transitions without mechanical limitations.
Solution Approach 2:
The patent implements preliminary detection of power source status by the control unit before switching occurs. The control unit monitors voltage levels and detects failures in advance, preparing the switching sequence beforehand. This preliminary action ensures that when a power source fails, the transition to backup power occurs instantly without interruption, maintaining continuous power supply to the load.
Data Source
AI summary
A power supply system for automatic transfer switch applications comprises two first switch apparatuses, two second switch apparatuses, and a control unit. Each first switch apparatus comprises a first relay switch and a first switch assembly. The first switch assembly comprises a first bypass switch, a first semi-controllable switch, and a first fully-controllable switch. Each second switch apparatus comprises a second relay switch and a second switch assembly. The second switch assembly comprises a second bypass switch, a second semi-controllable switch, and a second fully-controllable switch. The control unit controls the two first switch apparatuses and the two switch apparatuses to uninterruptedly supply power to a load.