Back to results
US 11,211,816 B1Granted
Delta connected resonant turn off circuits
AssigneeABB Schweiz AG
InventorsVeerakumar Bose, Thomas Kendzia, III, Christopher Alan Belcastro
Life of this patent
Estimating the term…
Abstract
A static transfer switch is provided for supplying power to a load alternately from two different power sources. Switching between the two power sources may occur within a fraction of one electrical cycle. In response to sensing degraded performance in the power source supplying the load, resonant turn off circuits connected directly to the main switches of two phases of the power source are actuated to commutate the respective main switches. The main switch of the third phase is commutated with one or more of the resonant turn off circuits through the delta side of a transformer connected to the three phases of the power source.
Claims21
A static transfer switch, comprising:
- a first three-phase electrical power source comprising a first phase A, a first phase B and a first phase C;
- a second three-phase electrical power source comprising a second phase A, a second phase B and a second phase C;
- a three-phase transformer comprising a delta side with a phase A input, a phase B input and a phase C input;
- a first phase A switch between the first phase A and the phase A input to the delta side of the three-phase transformer;
- a second phase A switch between the second phase A and the phase A input to the delta side of the three-phase transformer;
- a first phase B switch between the first phase B and the phase B input to the delta side of the three-phase transformer;
- a second phase B switch between the second phase B and the phase B input to the delta side of the three-phase transformer;
- a first phase C switch between the first phase C and the phase C input to the delta side of the three-phase transformer;
- a second phase C switch between the second phase C and the phase C input to the delta side of the three-phase transformer;
- a first resonant turn off circuit coupled to the first phase A switch;
- a second resonant turn off circuit coupled to the first phase B switch;
- wherein during a switching event, the first and second resonant turn off circuits force the first phase A switch and the first phase B switch to open, respectively, through a direct connection therebetween to disconnect the first phase A and the first phase B from the three-phase transformer;
- wherein during the switching event, the first and/or second resonant turn off circuits force the first phase C switch to open through the delta side of the three-phase transformer to disconnect the first phase C from the three-phase transformer;
- and
- wherein the during the switching event, the second phase A switch, the second phase B switch and the second phase C switch are closed to connect the second three-phase electrical power source to the three-phase transformer.
12 more elements
A static transfer switch, comprising:
- a set of first power inputs coupled to a first three-phase electrical power source, each of the first power inputs being coupled to one phase of the first three-phase electrical power source;
- a set of second power inputs coupled to a second three-phase electrical power source, each of the second power inputs being coupled to one phase of the second three-phase electrical power source;
- a set of power outputs coupled to a delta side of a three-phase transformer;
- a set of first switches coupled between the set of first power inputs and the set of power outputs;
- a set of second switches coupled between the set of second power inputs and the set of power outputs;
- a set of third switches coupled between a set of energy storages and two of the first switches, each third switch being coupled between one of the energy storages and a respective first switch;
- a sensor to determine an electrical property of the first three-phase electrical power source;
- a power transfer controller, the sensor being an input to the power transfer controller and the sets of first and second switches being outputs of the power transfer controller;
- wherein during normal operation the power transfer controller closes the set of first switches to electrically connect the set of first power inputs and the set of power outputs together and opens the set of second switches to electrically disconnect the set of second power inputs and the set of power outputs, the first three-phase electrical power source thereby supplying power to the three-phase transformer;
- wherein when the sensor identifies degraded performance of the first three-phase electrical power source, the power transfer controller initiates a switching event, comprising:
- turning off a gate signal to each of the first switches;
- closing at least one third switch between each of the two first switches and each respective energy storage after the gate signal of the respective first switch has been turned off, the set of energy storages thereby releasing a current to the input or output of the respective first switch to force a drop in current conducted through the respective first switch, the drop in current causing the respective first switch to open and stop conducting current therethrough between the first three-phase electrical power source and the three-phase transformer;
- opening a third one of the first switches with current conducted from one or more of the energy storages through the delta side of the three-phase transformer to force a drop in current conducted through the third one of the first switches, the drop in current causing the third one of the first switches to open and stop conducting current therethrough between the first three-phase electrical power source and the three-phase transformer without a separate energy storage or third switch for the third one of the first switches;
- closing the set of second switches after respective first switches have been opened, the second three-phase electrical power source thereby supplying power to the three-phase transformer.
11 more elements
Dependencies are inferred from the claim text.