Static Transfer Switch Off Detection And Transfer Management

• US 20140097689A1
• Filed: 03/14/2013
• Published: 04/10/2014
• Est. Priority Date: 09/14/2012
• Status: Active Grant

• Current Assignee: Vetriv S.R.L.
• Original Assignee: Chloride SRL (Emerson Electric Company)
• Inventors: GALUPPI, Graziano, BERTUZZI, Giancarlo, CINTI, Ugo
• Granted Patent: US 9,537,348 B2
• Time in Patent Office: Days
• US Class Current: 307/64
• CPC Class Codes: H02J 9/04 in which the distribution system is disconnected from the normal source and connected to a standby source
• CPC Class Codes: H03K 17/18 Modifications for indicating state of switch
• CPC Class Codes: H03K 17/725 for ac voltages or currents H03K17/722, H03K17/735 take precedence
• CPC Class Codes: H03K 17/735 Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors H03K17/722 takes precedence; logic circuits H03K19/00; code converters H03M5/00, H03M7/00

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.

Claims

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 to determine whether at least one of the first SCR or the second SCR is active, wherein the at least one of the first SCR or the second SCR is active when voltage between the gate and the cathode is at least 150 mV.

2. The static transfer switch of claim 1 wherein the first SCR communicates with a first firing circuit and the second SCR communicates with a second firing circuit.

3. The static transfer switch of claim 1 wherein the control circuit outputs a status signal in accordance with the activation of the at least one of the first or the second SCR.

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:

a first switching unit having a first pair of silicon controlled rectifiers (SCRs) arranged in an anti-parallel relationship; and

a second switching unit having a second pair of SCRs arranged in an anti-parallel relationship;

wherein the at least one of the SCRs is active when a voltage level of the at least one of the SCRs is at least 150 mV until direct current through the at least one of the SCRs is below a holding current level.

5. The static transfer switch of claim 4 further comprising a control circuit communicating with the at least one of the SCRs, the control circuit determining whether the at least one of the SCRs is active and generating an output signal in accordance with the activation of the at least one of the SCRs.

6. The static transfer switch of claim 5 wherein the control circuit outputs a control signal to activate at least one of the SCRs.

7. A static transfer switch, comprising:

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 maintaining 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 determines that the one of the first SCR or second SCR and the one of the third SCR or fourth SCR is active when the voltage between the gate and the cathode of the respective SCR is at least 150 mV.

8. The static transfer switch of claim 7 wherein the first switching unit communicates with a first firing circuit and the second switching unit communicates with a third firing circuit.

9. The static transfer switch of claim 7 wherein the first switching unit communicates with a second firing circuit and the second switching unit communicates with a fourth firing circuit, wherein the first, second, third, and fourth SCRs communicate with a respective first, second, third, and fourth firing circuit.