Static transfer switch
First Claim
1. A static transfer switch to transfer an output load from a first power source to a second power source, the static transfer switch comprising:
- a first switching unit having a first silicon controlled rectifier (SCR);
a second switching unit having a second SCR; and
a control circuit configured to determine whether at least one of the first SCR or the second SCR is inactive, wherein the at least one of the first SCR or the second SCR is inactive when voltage between a gate and a cathode of the at least one SCR falls below 150 mV and a direct current between an anode and a cathode of the at least one SCR falls below a holding current, and the control circuit is further configured so that when the voltage between the gate and the cathode of the at least one SCR is greater than 150 mV or the direct current between the anode and the cathode of the at least one SCR remains above the holding current, the at least one SCR is active.
3 Assignments
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Accused Products
Abstract
A static transfer switch is used for switching an output load from a first power source to a second power source. A first switching unit has a first pair of silicon controlled rectifiers (SCR). A second switching unit has a second pair of SCRs arranged in an anti-parallel configuration. The control circuit determines whether at least one of the SCRs is activated in accordance with the voltage between the gate and the cathode of the at least one SCR. If the voltage between the gate in the cathode is at least 150 mV, the control circuit indicates that the at least one of the SCR is activated.
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Citations
9 Claims
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1. A static transfer switch to transfer an output load from a first power source to a second power source, the static transfer switch comprising:
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a first switching unit having a first silicon controlled rectifier (SCR); a second switching unit having a second SCR; and a control circuit configured to determine whether at least one of the first SCR or the second SCR is inactive, wherein the at least one of the first SCR or the second SCR is inactive when voltage between a gate and a cathode of the at least one SCR falls below 150 mV and a direct current between an anode and a cathode of the at least one SCR falls below a holding current, and the control circuit is further configured so that when the voltage between the gate and the cathode of the at least one SCR is greater than 150 mV or the direct current between the anode and the cathode of the at least one SCR remains above the holding current, the at least one SCR is active. - View Dependent Claims (2, 3)
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4. A static transfer switch to transfer an output load from a first power source to a second power source, the static transfer switch comprising:
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a first switching unit having a first pair of silicon controlled rectifiers (SCRs) arranged in an anti-parallel relationship; a second switching unit having a second pair of SCRs arranged in an anti-parallel relationship; and a control circuit configured to determine whether at least one of the SCRs is inactive when a voltage level between a gate and a cathode of the at least one of the SCRs falls below 150 mV and a direct current between an anode and a cathode of the at least one SCR falls below a holding current, and the control circuit is further configured so that when the voltage between the gate and the cathode of the at least one SCR is greater than 150 mV or the direct current between the anode and the cathode of the at least one SCR remains above the holding current, the at least one SCR is active. - View Dependent Claims (5, 6)
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7. A static transfer switch, comprising:
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a first switching unit having a first silicon controlled rectifier (SCR) and a second SCR arranged in an anti-parallel relationship; a second switching unit having a third SCR and a fourth SCR arranged in an anti-parallel relationship; and a control circuit, the control circuit configured to maintain one of the first SCR or second SCR in an active state, wherein the control circuit activates one of the third SCR or fourth SCR, causing the one of the first SCR or second SCR to transition to a not active state via a reverse voltage, after which the other of the third SCR or fourth SCR may be active, wherein the control circuit is configured to determine whether the one of the first SCR or second SCR and the one of the third SCR or fourth SCR is inactive when the voltage between a gate and a cathode of the respective SCR falls below at least 150 mV and a direct current between an anode and a cathode of the one of the first SCR or second SCR and the one of the third SCR or fourth SCR falls below a holding current, and the control circuit is further configured so that when the voltage between the gate and the cathode is greater than 15 mV or the direct current between the anode and the cathode of the one of the first SCR or second SCR and the one of the third SCR or fourth SCR remains above the holding current, the SCR is determined to be active. - View Dependent Claims (8, 9)
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Specification