US20030067343A1 - Ac transfer switch using semiconductor devices - Google Patents
Ac transfer switch using semiconductor devices Download PDFInfo
- Publication number
- US20030067343A1 US20030067343A1 US09/974,252 US97425201A US2003067343A1 US 20030067343 A1 US20030067343 A1 US 20030067343A1 US 97425201 A US97425201 A US 97425201A US 2003067343 A1 US2003067343 A1 US 2003067343A1
- Authority
- US
- United States
- Prior art keywords
- line
- system load
- coupled
- sense circuit
- scrs
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
- H03K17/79—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled controlling bipolar semiconductor switches with more than two PN-junctions, or more than three electrodes, or more than one electrode connected to the same conductivity region
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/72—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region
- H03K17/735—Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors
Definitions
- the present invention relates generally to the data processing field, and more particularly, relates to an AC transfer switch utilizing semiconductor devices to switch between two or more AC lines.
- An AC transfer switch is used to switch between the different AC lines.
- Conventional ATS designs typically use electromechanical relay devices to switch between two or more AC lines. Electromechanical relay devices are much slower and much less reliable than semiconductor devices. Previous architectures using semiconductor devices have not been able to meet safety agency approvals.
- a principal object of the present invention is to provide an AC transfer switch (ATS) utilizing semiconductor components.
- Other important objects of the present invention are to provide such an AC transfer switch (ATS) utilizing semiconductor components substantially without negative effect and that overcome many of the disadvantages of prior art arrangements.
- an AC transfer switch 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.
- 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.
- SCRs silicon controlled rectifiers
- FIG. 1 is a schematic diagram illustrating an AC transfer switch (ATS) in accordance with the preferred embodiment
- FIG. 2 is a schematic diagram illustrating an exemplary logic and optical isolator circuit to drive line A or line B silicon controlled rectifiers (SCRs) of the AC transfer switch (ATS) of FIG. 1 in accordance with the preferred embodiment.
- SCRs silicon controlled rectifiers
- FIG. 1 there is illustrated an AC transfer switch (ATS) generally designated by the reference character 100 and arranged in accordance with the preferred embodiment.
- AC transfer switch 100 is used to switch a system load between a first AC line A and a second AC line B.
- AC transfer switch 100 includes a first pair of oppositely poled silicon controlled rectifiers (SCRs), a first SCR A- 1 102 and a second SCR A- 2 104 connected to a bridge rectifier (BRIDGE A) 106 A connected to the first AC line A.
- SCRs silicon controlled rectifiers
- BRIDGE A bridge rectifier
- AC transfer switch 100 includes a second pair of oppositely poled silicon controlled rectifiers (SCRs), a first SCR B- 1 102 and a second SCR B- 2 104 connected to a bridge rectifier (BRIDGE B) 106 B that is connected to the second AC line B.
- Bridge rectifier BRIDGE A 106 A includes four diodes 108 A, 110 A, 112 A and 114 A connected for full wave rectification of the input of AC line A.
- Bridge rectifier BRIDGE B 106 B includes four diodes 108 B, 110 B, 112 B and 114 B connected for full wave rectification of the input of AC line B.
- double insulated safety protection is provided between the AC mains generated hazardous voltage and an unplugged line cord of the AC transfer switch 100 .
- AC transfer switch 100 cannot present a safety hazard if a person physically touches the terminals of one of the AC transfer switch unplugged input AC line input, such as AC line A, while another input AC, such as AC line B, is connected to the potentially hazardous AC line.
- Double insulated safety protection must be provided between the AC line A and AC line B generated hazardous voltage and an unconnected AC line input, such as an unplugged line cord of the AC transfer switch.
- electromechanical relays provide this protection by physically separating the AC input of one AC line A from the other AC line B.
- relays are not required since the input AC lines A and B are separated from each other through SCR and bridge rectifier semiconductor devices, SCRs SCR A- 1 102 , SCR A- 2 104 ; SCR B- 1 104 , SCR B- 2 102 and bridge rectifier BRIDGE A 106 A, BRIDGE B 106 B.
- the safety isolation of the series combination of an SCR and bridge rectifier described by the preferred embodiment has been used to achieve safety isolation in a 192V DC battery back-up between an unplugged AC line cord and the hazardous voltage created by a 192V battery string.
- the DC battery back-up using this isolation has UL, CSA and European safety agency approvals. If the AC transfer switch 100 is running off of AC line A and the line cord receptacle for AC line B is physically unplugged, two semiconductor devices, SCRs 102 , 104 and bridge rectifier 106 A, 106 B, must fail in order for hazardous voltage or energy to become available on AC line cord receptacle B. This double fault protection of the AC transfer switch 100 meets safety agency requirements.
- electromechanical relays have an intrinsic failure rate that is at least 3.1 times greater than that of semiconductor devices even for the worst semiconductor suppliers.
- Speed of a relay device is dependent on its size. The larger the relay, the slower its switching transition.
- a relay In order to meet IBM power line disturbance requirements a relay must be able to switch within 10 milliseconds. Lab experience shows the largest relay to switch this fast is rated at 5 amperes.
- the use of parallel relays is required. Wiring relays in parallel requires more cost and more space. Parallel relays will not always switch at the same time.
- the first relay to switch will be operating above its rating for a short amount of time contributing to an early life failure. While a semiconductor device's speed is also dependent on its size, a very large semiconductor rated at 30 amperes can achieve switching transitions in the order of microseconds.
- AC line A is fed through the bridge rectifier (BRIDGE A) 106 A where the AC line voltage is rectified into a full wave rectified AC waveform.
- the rectified waveform of the bridge rectifier (BRIDGE A) 106 A is applied to the anode of silicon-controlled-rectifier (SCR) A- 1 102 and the cathode of SCR A- 2 104 .
- the input AC line A is sensed by line A AC sense circuit 116 A via a first pair of diodes 118 A, 120 A connected to AC line A before the bridge rectifier (BRIDGE A) 106 A.
- AC line B similarly is fed through a bridge rectifier (BRIDGE B) 106 B where the AC line voltage is rectified into a full wave rectified AC waveform.
- the rectified waveform of the bridge rectifier (BRIDGE B) 106 B is applied to the anode of silicon-controlled-rectifier (SCR) B- 1 102 and the cathode of SCR B- 2 104 .
- the input AC line B similarly is sensed by a line B AC sense circuit 116 B via a second pair of diodes 118 B, 120 B connected to AC line B before the bridge rectifier (BRIDGE B) 106 B.
- a respective one of a pair of gate drives 122 A, 122 B is connected to the SCRs A- 1 102 , A- 2 104 of line A and the SCRs B- 1 102 , B- 2 104 of line B.
- the outputs of line A AC sense circuit 116 A and line B AC sense circuit 116 B are applied to logic and optical isolator circuit 124 providing control inputs to the pair of gate drives 122 A, 122 B to drive line A SCRs A- 1 102 , A- 2 104 or line B SCRs B- 1 102 , B- 2 104 .
- AC transfer switch 100 In operation of AC transfer switch 100 initially if AC line A is sensed to be within a specified AC line tolerance by line A AC sense circuit 116 A, the logic and optical isolator circuit 124 drives SCR A- 1 102 and SCR A- 2 , 104 on via gate drive of SCRs line A 122 A while keeping SCR B- 1 102 and SCR B- 2 104 off via gate drive of SCRs line B 122 B. Once SCR A- 1 102 and SCR A- 2 104 are on, the rectified AC voltage of line A is available to the system load.
- the logic and optical isolator circuit 124 drives SCR B- 1 102 and SCR B- 2 104 on via gate drive of SCRs line B 122 B, while keeping SCR A- 1 102 and SCR A- 2 104 off via gate drive of SCRs line A 122 A. Once SCR B- 1 102 and SCR B- 2 104 are on, the rectified AC voltage of line B will be available to the system load.
- AC line A is the default AC line whenever AC line A is within the specified AC line tolerance. If AC line A is not within the specified AC line tolerance and AC line B is within the specified AC line tolerance, the AC transfer switch 100 will supply AC line B to the load. If the AC transfer switch 100 is supplying AC line B to the load and AC line A falls within the specified tolerance, AC transfer switch 100 will switch to AC line A once AC line A has been determined to be stable. A switch of the AC lines will not occur unless AC line A falls out of tolerance. In the case where both AC lines come up at the same time, the logic defaults to AC line A. The transition from AC line A to AC line B is less than 5 milliseconds or a time depending on the speed of the AC sensing circuits.
- the semiconductor AC transfer switch 100 provides full-wave rectified AC to the connected system load.
- Most IT equipment can run off of full-wave rectified AC. Almost 100% of IT equipment power supplies are designed such that they will run off of full-wave rectified AC.
- a load of an AC motor or a 50/60 Hz transformer would not be directly connected to the semiconductor AC transfer switch 100 , since these devices require full wave AC voltage.
- Logic and optical isolator circuit 124 to drive line A or line B silicon controlled rectifiers (SCRs) 102 , 104 of the AC transfer switch 100 .
- Logic and optical isolator circuit 124 includes a first N-channel field effect transistor (NFET) 202 having a gate input from the line A AC sense circuit 116 A.
- NFET 202 is coupled between a DC voltage supply rail VCC and a first optical isolator 204 with a first resistor 206 connected between NFET 202 and the DC voltage supply rail VCC.
- Logic and optical isolator circuit 124 includes a second N-channel field effect transistor (NFET) 210 having a gate input from the line B AC sense circuit 116 B.
- NFET N-channel field effect transistor
- NFET 210 is coupled between the DC voltage supply rail VCC and a second optical isolator 212 via a resistor 214 .
- a third NFET 216 connected between the gate of FET 210 and ground has a gate input coupled to the drain of FET 202 .
- a parallel connected diode 220 and a resistor 222 connected to the DC voltage supply rail VCC is connected in series with a capacitor 224 that is connected to ground.
- the gate of NFET 218 is connected to bias voltage provided by diode 220 , resistor 222 and capacitor 224 .
- the circuit of NFET 218 , diode 220 , resistor 222 and capacitor 224 is used to keep the optical isolators 204 and 212 off when the DC voltage supply rail VCC is not within tolerance.
- the first optical isolator 204 provides an optically isolated line A SCR gate drive for SCR A- 1 102 , SCR A- 2 , 104 .
- NFET 216 is turned on when NFET 202 is activated keeping NFET 210 off and keeping the second optical isolator 212 off and SCR B- 1 102 and SCR B- 2 104 off.
- NFET 202 is turned off, keeping the first optical isolator 204 off, and SCR A- 1 102 , SCR A- 2 , 104 off. Then NFET 216 is turned off and NFET 210 is turned on via the gate input from Line B AC sense circuit 116 B, the second optical isolator 212 provides an optically isolated line B SCR gate drive for SCR B- 1 102 , SCR B- 2 , 104 .
- the preferred embodiment implements the semiconductor AC transfer switch 100 with AC line A being the default AC line
- the semiconductor AC transfer switch 100 can be implemented so that AC line B is the default AC line or that the first AC line that is within the specified tolerance is the default AC line.
- the semiconductor AC transfer switch 100 of the preferred embodiment with AC line A being the default AC line is provided for customers using the AC transfer switch to balance loads across specified AC lines.
- the semiconductor AC transfer switch 100 of the preferred embodiment provides a faster, less expensive and more reliable method of switching between AC voltage supply grids than conventional relay ATS designs.
Landscapes
- Electronic Switches (AREA)
Abstract
Description
- The present invention relates generally to the data processing field, and more particularly, relates to an AC transfer switch utilizing semiconductor devices to switch between two or more AC lines.
- Applications requiring an AC transfer switch are increasing. Information technology customers are required to run 24 hours a day, 7 days a week for 365 days a year. In order to achieve this kind of up time, many information technology customers are requiring their equipment to be plugged into two separate AC main grids. When a first AC line goes down, the information technology equipment will run off a second AC line. The two separate power grids are distributed throughout the customer's facility.
- Information technology equipment must be able to reliably, quickly and safely switch between a bad AC line to a good AC line without affecting equipment operation.
- An AC transfer switch (ATS) is used to switch between the different AC lines. Conventional ATS designs typically use electromechanical relay devices to switch between two or more AC lines. Electromechanical relay devices are much slower and much less reliable than semiconductor devices. Previous architectures using semiconductor devices have not been able to meet safety agency approvals.
- A need exists for an AC transfer switch (ATS) capable of reliably, quickly and safely switching between AC lines. It is desirable to provide an AC transfer switch (ATS) utilizing semiconductor components capable of reliably, quickly and safely switching between two or more AC lines.
- A principal object of the present invention is to provide an AC transfer switch (ATS) utilizing semiconductor components. Other important objects of the present invention are to provide such an AC transfer switch (ATS) utilizing semiconductor components substantially without negative effect and that overcome many of the disadvantages of prior art arrangements.
- In brief, an AC transfer switch (ATS) for switching a system load between at least two AC lines is provided. 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.
- In accordance with features of the invention, 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.
- The present invention together with the above and other objects and advantages may best be understood from the following detailed description of the preferred embodiments of the invention illustrated in the drawings, wherein:
- FIG. 1 is a schematic diagram illustrating an AC transfer switch (ATS) in accordance with the preferred embodiment;
- FIG. 2 is a schematic diagram illustrating an exemplary logic and optical isolator circuit to drive line A or line B silicon controlled rectifiers (SCRs) of the AC transfer switch (ATS) of FIG. 1 in accordance with the preferred embodiment.
- Having reference now to the drawings, in FIG. 1 there is illustrated an AC transfer switch (ATS) generally designated by the
reference character 100 and arranged in accordance with the preferred embodiment.AC transfer switch 100 is used to switch a system load between a first AC line A and a second AC line B.AC transfer switch 100 includes a first pair of oppositely poled silicon controlled rectifiers (SCRs), afirst SCR A-1 102 and asecond SCR A-2 104 connected to a bridge rectifier (BRIDGE A) 106A connected to the first AC line A.AC transfer switch 100 includes a second pair of oppositely poled silicon controlled rectifiers (SCRs), a first SCR B-1 102 and a second SCR B-2 104 connected to a bridge rectifier (BRIDGE B) 106B that is connected to the second AC line B. Bridge rectifier BRIDGE A 106A includes fourdiodes diodes - In accordance with features of the preferred embodiment, double insulated safety protection is provided between the AC mains generated hazardous voltage and an unplugged line cord of the
AC transfer switch 100. In order to meet safety agency requirements,AC transfer switch 100 cannot present a safety hazard if a person physically touches the terminals of one of the AC transfer switch unplugged input AC line input, such as AC line A, while another input AC, such as AC line B, is connected to the potentially hazardous AC line. Double insulated safety protection must be provided between the AC line A and AC line B generated hazardous voltage and an unconnected AC line input, such as an unplugged line cord of the AC transfer switch. In other conventional ATS designs, electromechanical relays provide this protection by physically separating the AC input of one AC line A from the other AC line B. In the semiconductorAC transfer switch 100 of the preferred embodiment, relays are not required since the input AC lines A and B are separated from each other through SCR and bridge rectifier semiconductor devices,SCRs SCR A-1 102, SCRA-2 104; SCR B-1 104, SCR B-2 102 and bridge rectifier BRIDGE A 106A, BRIDGE B 106B. - The safety isolation of the series combination of an SCR and bridge rectifier described by the preferred embodiment has been used to achieve safety isolation in a 192V DC battery back-up between an unplugged AC line cord and the hazardous voltage created by a 192V battery string. The DC battery back-up using this isolation has UL, CSA and European safety agency approvals. If the
AC transfer switch 100 is running off of AC line A and the line cord receptacle for AC line B is physically unplugged, two semiconductor devices,SCRs bridge rectifier AC transfer switch 100 meets safety agency requirements. - Advantages of using semiconductor devices of the
AC transfer switch 100 over electromechanical relays are speed, reliability and cost. According to reliability engineering analysis, electromechanical relays have an intrinsic failure rate that is at least 3.1 times greater than that of semiconductor devices even for the worst semiconductor suppliers. Speed of a relay device is dependent on its size. The larger the relay, the slower its switching transition. In order to meet IBM power line disturbance requirements a relay must be able to switch within 10 milliseconds. Lab experience shows the largest relay to switch this fast is rated at 5 amperes. In order to build an AC transfer switch rated at more than 5 amperes, the use of parallel relays is required. Wiring relays in parallel requires more cost and more space. Parallel relays will not always switch at the same time. The first relay to switch will be operating above its rating for a short amount of time contributing to an early life failure. While a semiconductor device's speed is also dependent on its size, a very large semiconductor rated at 30 amperes can achieve switching transitions in the order of microseconds. - Referring to FIG. 1, in the
AC transfer switch 100, AC line A is fed through the bridge rectifier (BRIDGE A) 106A where the AC line voltage is rectified into a full wave rectified AC waveform. The rectified waveform of the bridge rectifier (BRIDGE A) 106A is applied to the anode of silicon-controlled-rectifier (SCR)A-1 102 and the cathode ofSCR A-2 104. The input AC line A is sensed by line AAC sense circuit 116A via a first pair ofdiodes AC sense circuit 116B via a second pair ofdiodes gate drives SCRs A-1 102,A-2 104 of line A and the SCRs B-1 102, B-2 104 of line B. The outputs of line AAC sense circuit 116A and line BAC sense circuit 116B are applied to logic andoptical isolator circuit 124 providing control inputs to the pair ofgate drives A SCRs A-1 102,A-2 104 or line B SCRs B-1 102, B-2 104. - In operation of
AC transfer switch 100 initially if AC line A is sensed to be within a specified AC line tolerance by line AAC sense circuit 116A, the logic andoptical isolator circuit 124drives SCR A-1 102 and SCR A-2, 104 on via gate drive ofSCRs line A 122A while keeping SCR B-1 102 and SCR B-2 104 off via gate drive ofSCRs line B 122B. OnceSCR A-1 102 andSCR A-2 104 are on, the rectified AC voltage of line A is available to the system load. - If AC line A is sensed to be outside a specified AC line tolerance by line A
AC sense circuit 116A, and AC line B is sensed to be within the specified AC line tolerance by line BAC sense circuit 116B, the logic andoptical isolator circuit 124 drives SCR B-1 102 and SCR B-2 104 on via gate drive ofSCRs line B 122B, while keepingSCR A-1 102 andSCR A-2 104 off via gate drive ofSCRs line A 122A. Once SCR B-1 102 and SCR B-2 104 are on, the rectified AC voltage of line B will be available to the system load. - In operation of
AC transfer switch 100, AC line A is the default AC line whenever AC line A is within the specified AC line tolerance. If AC line A is not within the specified AC line tolerance and AC line B is within the specified AC line tolerance, theAC transfer switch 100 will supply AC line B to the load. If theAC transfer switch 100 is supplying AC line B to the load and AC line A falls within the specified tolerance,AC transfer switch 100 will switch to AC line A once AC line A has been determined to be stable. A switch of the AC lines will not occur unless AC line A falls out of tolerance. In the case where both AC lines come up at the same time, the logic defaults to AC line A. The transition from AC line A to AC line B is less than 5 milliseconds or a time depending on the speed of the AC sensing circuits. - Unlike conventional relay driven ATS designs that provide full wave AC to the system plugged into them, the semiconductor
AC transfer switch 100 provides full-wave rectified AC to the connected system load. Most IT equipment can run off of full-wave rectified AC. Almost 100% of IT equipment power supplies are designed such that they will run off of full-wave rectified AC. A load of an AC motor or a 50/60 Hz transformer would not be directly connected to the semiconductorAC transfer switch 100, since these devices require full wave AC voltage. - Referring to FIG. 2, there is shown exemplary logic and
optical isolator circuit 124 to drive line A or line B silicon controlled rectifiers (SCRs) 102, 104 of theAC transfer switch 100. Logic andoptical isolator circuit 124 includes a first N-channel field effect transistor (NFET) 202 having a gate input from the line AAC sense circuit 116A.NFET 202 is coupled between a DC voltage supply rail VCC and a firstoptical isolator 204 with afirst resistor 206 connected betweenNFET 202 and the DC voltage supply rail VCC. Logic andoptical isolator circuit 124 includes a second N-channel field effect transistor (NFET) 210 having a gate input from the line BAC sense circuit 116B.NFET 210 is coupled between the DC voltage supply rail VCC and a secondoptical isolator 212 via aresistor 214. Athird NFET 216 connected between the gate ofFET 210 and ground has a gate input coupled to the drain ofFET 202. Afourth NFET 218 connected between the connection of cathodes ofoptical isolators connected diode 220 and aresistor 222 connected to the DC voltage supply rail VCC is connected in series with acapacitor 224 that is connected to ground. The gate ofNFET 218 is connected to bias voltage provided bydiode 220,resistor 222 andcapacitor 224. The circuit ofNFET 218,diode 220,resistor 222 andcapacitor 224 is used to keep theoptical isolators - When
NFET 202 is activated via the gate input from Line AAC sense circuit 116A, the firstoptical isolator 204 provides an optically isolated line A SCR gate drive forSCR A-1 102, SCR A-2, 104.NFET 216 is turned on whenNFET 202 is activated keepingNFET 210 off and keeping the secondoptical isolator 212 off and SCR B-1 102 and SCR B-2 104 off. If AC line A is sensed to be outside a specified AC line tolerance by line AAC sense circuit 116A and AC line B is sensed to be within the specified AC line tolerance by line BAC sense circuit 116B, then NFET 202 is turned off, keeping the firstoptical isolator 204 off, andSCR A-1 102, SCR A-2, 104 off. ThenNFET 216 is turned off andNFET 210 is turned on via the gate input from Line BAC sense circuit 116B, the secondoptical isolator 212 provides an optically isolated line B SCR gate drive for SCR B-1 102, SCR B-2, 104. - Although the preferred embodiment implements the semiconductor
AC transfer switch 100 with AC line A being the default AC line, it should be understood that the semiconductorAC transfer switch 100 can be implemented so that AC line B is the default AC line or that the first AC line that is within the specified tolerance is the default AC line. The semiconductorAC transfer switch 100 of the preferred embodiment with AC line A being the default AC line is provided for customers using the AC transfer switch to balance loads across specified AC lines. - In brief summary, the semiconductor
AC transfer switch 100 of the preferred embodiment provides a faster, less expensive and more reliable method of switching between AC voltage supply grids than conventional relay ATS designs. - While the present invention has been described with reference to the details of the embodiments of the invention shown in the drawing, these details are not intended to limit the scope of the invention as claimed in the appended claims.
Claims (19)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/974,252 US6542023B1 (en) | 2001-10-10 | 2001-10-10 | AC transfer switch using semiconductor devices |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/974,252 US6542023B1 (en) | 2001-10-10 | 2001-10-10 | AC transfer switch using semiconductor devices |
Publications (2)
Publication Number | Publication Date |
---|---|
US6542023B1 US6542023B1 (en) | 2003-04-01 |
US20030067343A1 true US20030067343A1 (en) | 2003-04-10 |
Family
ID=30116330
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/974,252 Expired - Fee Related US6542023B1 (en) | 2001-10-10 | 2001-10-10 | AC transfer switch using semiconductor devices |
Country Status (1)
Country | Link |
---|---|
US (1) | US6542023B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10491036B1 (en) * | 2017-03-30 | 2019-11-26 | Amazon Technologies, Inc. | Solid-state automatic transfer switch |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6630753B2 (en) * | 2001-10-29 | 2003-10-07 | International Business Machines Corporation | Low cost redundant AC to DC power supply |
US7777600B2 (en) * | 2004-05-20 | 2010-08-17 | Powerpath Technologies Llc | Eddy current inductive drive electromechanical liner actuator and switching arrangement |
US7368836B2 (en) * | 2005-03-31 | 2008-05-06 | Power Distribution, Inc. | Volt-second synchronization for magnetic loads |
KR100559955B1 (en) | 2005-09-21 | 2006-03-13 | 한광전기공업주식회사 | Electrical automatic transfer switch having thermal overload protection |
US8232680B2 (en) * | 2009-12-21 | 2012-07-31 | International Business Machines Corporation | Selecting a single AC source for a switching power supply |
US9250274B2 (en) * | 2011-08-25 | 2016-02-02 | Asco Power Technologies, L.P. | Power analysis module for monitoring an electrical power source |
US9166410B1 (en) | 2012-03-14 | 2015-10-20 | Google Inc. | Line balancing for a three-phase alternating current system |
US9490663B1 (en) | 2012-07-16 | 2016-11-08 | Google Inc. | Apparatus and methodology for battery backup circuit and control in an uninterruptible power supply |
BR112015024546A2 (en) * | 2013-03-27 | 2017-07-18 | Flexenclosure Ab Publ | power supply apparatus, power supply system, and, power switching method |
US11050250B2 (en) | 2015-10-30 | 2021-06-29 | Abb Schweiz Ag | Static transfer switch system with real time flux control |
US10355514B2 (en) * | 2016-08-29 | 2019-07-16 | Apple Inc. | Rectifier arbitration in wireless charging systems |
US11747373B2 (en) | 2020-12-04 | 2023-09-05 | International Business Machines Corporation | Detecting electrical power line disturbances |
TWI811805B (en) * | 2021-10-05 | 2023-08-11 | 群光電能科技股份有限公司 | Power supply, power management module and power management method |
Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3243605A (en) * | 1963-08-08 | 1966-03-29 | Potter Instrument Co Inc | Simplified method for scr turnoff |
US3348063A (en) * | 1963-09-16 | 1967-10-17 | Monsanto Co | Solid state a-c contactor with momentary start-stop buttons |
US3308340A (en) * | 1964-05-04 | 1967-03-07 | Marquette Corp | Current control apparatus having phase controlled means for variably controlling the period of conduction |
DE1763303A1 (en) * | 1968-05-02 | 1970-08-13 | Bosch Gmbh Robert | Voltage regulator for a permanent magnet excited alternator |
US3678354A (en) * | 1968-10-16 | 1972-07-18 | Canon Kk | A dc motor control apparatus |
US3601674A (en) * | 1970-02-05 | 1971-08-24 | Gen Electric | Control system for firing scr{3 s in power conversion apparatus |
US4197992A (en) * | 1977-11-14 | 1980-04-15 | Leonard Klebanoff | Thermostat control device |
US4335321A (en) * | 1979-12-14 | 1982-06-15 | American Standard Inc. | Electronic balance control circuit arrangement |
US4747061A (en) | 1986-03-17 | 1988-05-24 | Westinghouse Electric Corp. | Automatic transfer switch for a wide range of source voltage |
US4791545A (en) * | 1987-04-20 | 1988-12-13 | Unisys Corporation | Zero-crossover SCR power supply regulator |
US4761563A (en) | 1987-10-27 | 1988-08-02 | International Business Machines Corporation | Asynchronous multiphase switching gear |
US5182464A (en) | 1991-01-09 | 1993-01-26 | Techmatics, Inc. | High speed transfer switch |
US5566339A (en) | 1992-10-23 | 1996-10-15 | Fox Network Systems, Inc. | System and method for monitoring computer environment and operation |
US5892299A (en) | 1996-09-24 | 1999-04-06 | Siewert; James Carl | Simultaneous power supply source |
US6046917A (en) * | 1999-05-03 | 2000-04-04 | Eaton Corporation | Controlled rectifier bridge and system |
US6317346B1 (en) * | 2000-11-09 | 2001-11-13 | At&T Corporation | Redundant multiphase power supplies for common load device |
-
2001
- 2001-10-10 US US09/974,252 patent/US6542023B1/en not_active Expired - Fee Related
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10491036B1 (en) * | 2017-03-30 | 2019-11-26 | Amazon Technologies, Inc. | Solid-state automatic transfer switch |
Also Published As
Publication number | Publication date |
---|---|
US6542023B1 (en) | 2003-04-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6542023B1 (en) | AC transfer switch using semiconductor devices | |
US5790394A (en) | Dual AC power supply input module | |
US11070047B2 (en) | Overcurrent protection driving circuit and display apparatus | |
US5179337A (en) | Over-discharge protection for rechargeable batteries | |
US4659942A (en) | Fault-tolerant power distribution system | |
US20100042344A1 (en) | System and method for detecting an electrical short across a static switch of an uninterruptible power supply | |
CN104578383A (en) | Input redundant circuit | |
GB2326035A (en) | Overvoltage and surge protection circuit for hard disk drive | |
US20020145895A1 (en) | Power supply system with AC redundant power sources and safety device | |
US7763993B2 (en) | DC UPS with auto-ranging backup voltage capability | |
US4628431A (en) | Power supply on/off switching with inrush limiting | |
CN102150339B (en) | Redundant power supply | |
CN112542880A (en) | Input power switching circuit, system and method for single-input redundant power module | |
EP0389515B1 (en) | Integratable synchronous rectifier | |
US4311950A (en) | Excitation system for a synchronous machine | |
US5656871A (en) | Circuit arrangement for an uninterrupted power supply | |
TW201023479A (en) | Loop apparatus and method with low voltage and dual power | |
JPS61220221A (en) | Fault detector for switch | |
JP3108851B2 (en) | Overvoltage detection circuit | |
JPS6359717A (en) | Dc voltage feeder circuit | |
JP3051320B2 (en) | Power supply for communication equipment | |
JPS61231846A (en) | Direct transmission interruption-free switch type power failure free power source unit | |
Rosenberg | Trends in telecom power supplies | |
JP2005260721A (en) | Solid state relay | |
JPS60139126A (en) | Electronic device |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: INTERNATIONAL BUSINESS MACHINES CORPORATION, NEW Y Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:DAUN-LINDBERG, TIMOTHY CHARLES;PENTEK, CHARLES J.;STEELE, STEVEN WILLIAM;AND OTHERS;REEL/FRAME:012258/0031 Effective date: 20011009 |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
LAPS | Lapse for failure to pay maintenance fees |
Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20110401 |