Techniques for improving operation of static transfer switches during voltage disturbances
First Claim
Patent Images
1. A static transfer switch, comprising:
- a preferred input terminal configured to receive an AC voltage signal from a preferred voltage source;
a data port configured to receive a message via a data link from a device associated with the preferred voltage source, where the message is indicative of a voltage disturbance in the voltage signal;
a load terminal;
a first switch arrangement electrically connected between the preferred input terminal and the load terminal and operates to selectively output the voltage signal to the load terminal, wherein the first switch arrangement includes one or more semiconductor switches; and
a controller configured to receive the message from the data port and operable, in response to receiving the message, to initiate a timer and compare duration of the timer to a threshold,wherein the controller, in response to the duration being less than the threshold, to controls conductive state of the semiconductor switches to change waveform of the voltage signal output by the first switch arrangement to the load terminal, thereby avoiding magnetic flux saturation in a downstream transformer; and
wherein the controller, in response to the duration being greater than the threshold, couple an alternate input terminal to the load terminal, where the alternate input terminal is configured to receive an AC voltage signal from an alternate voltage source.
9 Assignments
0 Petitions
Accused Products
Abstract
When the preferred voltage source for a static transfer switch is a UPS, there can be a brief interruption in the voltage received from the UPS while the UPS is switching from economy mode to normal mode. Operation of the static transfer switch can be improved during such voltage disturbances. Specifically, the static transfer switch may be in data communication with the UPS and thereby made aware that the voltage disturbance is temporary. As a result, the static transfer switch can avoid an unnecessary transfer to an alternate voltage source.
-
Citations
16 Claims
-
1. A static transfer switch, comprising:
-
a preferred input terminal configured to receive an AC voltage signal from a preferred voltage source; a data port configured to receive a message via a data link from a device associated with the preferred voltage source, where the message is indicative of a voltage disturbance in the voltage signal; a load terminal; a first switch arrangement electrically connected between the preferred input terminal and the load terminal and operates to selectively output the voltage signal to the load terminal, wherein the first switch arrangement includes one or more semiconductor switches; and a controller configured to receive the message from the data port and operable, in response to receiving the message, to initiate a timer and compare duration of the timer to a threshold, wherein the controller, in response to the duration being less than the threshold, to controls conductive state of the semiconductor switches to change waveform of the voltage signal output by the first switch arrangement to the load terminal, thereby avoiding magnetic flux saturation in a downstream transformer; and wherein the controller, in response to the duration being greater than the threshold, couple an alternate input terminal to the load terminal, where the alternate input terminal is configured to receive an AC voltage signal from an alternate voltage source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A static transfer switch, comprising:
-
a preferred input terminal configured to receive an AC voltage signal from a preferred voltage source; a load terminal; a first switch arrangement electrically connected between the preferred input terminal and the load terminal and operates to selectively output the voltage signal to the load terminal, wherein the first switch arrangement includes one or more semiconductor switches; and a controller configured to detect a voltage disturbance in a given half cycle of the voltage signal and operable, in response to detecting the voltage disturbance, to control conductive state of the semiconductor switches to change waveform during a next half cycle of the voltage signal immediately following the given half cycle, thereby avoiding magnetic flux saturation in a downstream transformer; wherein the controller determines a quantity of sag in a nominal waveform of the voltage signal in the given half cycle of the voltage signal and controls conductive state of the semiconductor switches such that magnitude of voltage output to the load terminal during the next half cycle correlates to quantity of sag. - View Dependent Claims (13, 14, 15, 16)
-
Specification