AC transfer switch using semiconductor devices
First Claim
1. An AC transfer switch for switching a system load between at least two AC lines comprising:
- a first bridge rectifier connected to a first AC line for providing a first full wave rectified AC waveform;
a first pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to said first bridge rectifier and to the system load;
a second bridge rectifier connected to a second AC line for providing a second full wave rectified AC waveform;
a second pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to said second bridge rectifier and to the system load; and
control logic coupled to a gate input of said first pair of oppositely poled silicon controlled rectifiers (SCRs) and a gate input of said second pair of oppositely poled silicon controlled rectifiers (SCRs) for applying one of said first full wave rectified AC waveform or said second full wave rectified AC waveform to the system load.
1 Assignment
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Accused Products
Abstract
An AC transfer switch (ATS) is provided for switching a system load between at least two AC lines. A first bridge rectifier is connected to a first AC line for providing a first full wave rectified AC waveform. A first pair of oppositely poled silicon controlled rectifiers (SCRs) is coupled to the first bridge rectifier and to the system load. A second bridge rectifier is connected to a second AC line for providing a second full wave rectified AC waveform. A second pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to the second bridge rectifier and to the system load. Control logic is coupled to a gate input of the first pair of oppositely poled silicon controlled rectifiers (SCRs) and a gate input of the second pair of oppositely poled silicon controlled rectifiers (SCRs) for applying one of the first full wave rectified AC waveform or the second full wave rectified AC waveform to the system load. The control logic includes a first AC line sense circuit for sensing the first AC line input and a second AC line sense circuit for sensing the second AC line input. A first optical isolator is responsive to an output signal provided by the first AC line sense circuit sensing the first AC line input within a predefined AC line tolerance for activating the gate input of the first pair of oppositely poled silicon controlled rectifiers (SCRs) and applying the first full wave rectified AC waveform to the system load. A second optical isolator is responsive to an output signal provided by the first AC line sense circuit sensing the first AC line input outside the predefined AC line tolerance and an output signal provided by the second AC line sense circuit sensing the second AC line input within the predefined AC line tolerance for activating the gate input of the second pair of oppositely poled silicon controlled rectifiers (SCRs) and applying the second full wave rectified AC waveform to the system load.
40 Citations
19 Claims
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1. An AC transfer switch for switching a system load between at least two AC lines comprising:
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a first bridge rectifier connected to a first AC line for providing a first full wave rectified AC waveform;
a first pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to said first bridge rectifier and to the system load;
a second bridge rectifier connected to a second AC line for providing a second full wave rectified AC waveform;
a second pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to said second bridge rectifier and to the system load; and
control logic coupled to a gate input of said first pair of oppositely poled silicon controlled rectifiers (SCRs) and a gate input of said second pair of oppositely poled silicon controlled rectifiers (SCRs) for applying one of said first full wave rectified AC waveform or said second full wave rectified AC waveform to the system load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An AC transfer switch for switching a system load between at least two AC lines comprising:
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a first bridge rectifier connected to a first AC line for providing a first full wave rectified AC waveform;
a first pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to said first bridge rectifier and to the system load;
a second bridge rectifier connected to a second AC line for providing a second full wave rectified AC waveform;
a second pair of oppositely poled silicon controlled rectifiers (SCRs) coupled to said second bridge rectifier and to the system load; and
a first optical isolator coupled to a gate input of said first pair of oppositely poled silicon controlled rectifiers (SCRs);
a second optical isolator coupled to a gate input of said second pair of oppositely poled silicon controlled rectifiers (SCRs);
a first AC line sense circuit for sensing the first AC line input;
a second AC line sense circuit for sensing the second AC line input;
control logic coupled to said first AC line sense circuit and said second AC line sense circuit;
said control logic for activating said first optical isolator and applying said first full wave rectified AC waveform to the system load responsive to said first AC line sense circuit sensing said first AC line input within a predefined AC line tolerance; and
said control logic for deactivating said first optical isolator responsive to said AC line sense circuit sensing said first AC line input outside a predefined AC line tolerance and for activating said second optical isolator and applying said second full wave rectified AC waveform to the system load responsive to said second AC line sense circuit sensing said second AC line input within a predefined AC line tolerance.- View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification