Abstract:
A power switching device includes a primary power source, a backup power source, and a power switching circuit, and the power switching circuit can switch rapidly between the two or more power sources. The power switching circuit includes a first switching module, a second switching module, and a control module. The first switching module includes first through fourth relays, and first through fourth driving units. The first switching module also includes a first bidirectional thyristor and a second bidirectional thyristor. A power switching circuit is also provided.

Description:
FIELD 
       [0001]    The subject matter herein generally relates to a device and a circuit for power switching. 
       BACKGROUND 
       [0002]    An automatic transfer switch is used to switch power among two power sources. The automatic transfer switch should keep operating to be ready to switch power. That will cost lot of electric energy. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
           [0004]      FIG. 1  is a block diagram of an embodiment of a power switching device of the present disclosure. 
           [0005]      FIG. 2  is a circuit diagram of the embodiment of the power switching device in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0006]    It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. 
         [0007]    Several definitions that apply throughout this disclosure will now be presented. 
         [0008]    The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently coupled or releasably coupled. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the like. 
         [0009]    The disclosure will now be described in relation to a power switching device. 
         [0010]      FIG. 1  illustrates an embodiment of a power switching device  100 . 
         [0011]    The power switching device  100  can comprise a primary power source  10 , a backup power source  11 , and a power switching circuit  200 . 
         [0012]    The power switching circuit  200  can comprise a first switching module  12 , a second switching module  13 , and a control module  14 . 
         [0013]    The primary power source  10  is coupled to the first switching module  12 . The backup power source  11  is coupled to the second switching module  13 . The control module  14  is coupled to the first switching module  12  and the second switching module  13 . 
         [0014]    The first switching module  12  and the second switching module  13  are coupled to a load  20 . 
         [0015]    The first switching module  12  is coupled to the primary power source  10  to transmit power from the primary power source  10  to the load  20 . When the primary power source  10  fails to supply a voltage for the operating of the load  20 , the control module  14  controls the first switching module  12  to disconnect the connection between the primary power source  10  and the load  20 , and the control module  14  controls the second switching module  13  to connect the backup power source  11  to the load  20 . The backup power source  11  then supplies power for the load  20 . 
         [0016]      FIG. 2  illustrates a circuit of the power switching device  100 . 
         [0017]    The first switching module  12  can comprise a first relay  121 , a second relay  122 , a third relay  123 , a fourth relay  124 , a first driving unit  125 , a second driving unit  126 , a third driving unit  127 , a fourth driving unit  128 , a first bidirectional thyristor TR 1 , and a second bidirectional thyristor TR 2 . 
         [0018]    The second switching module  13  can comprise a fifth relay  131 , a sixth relay  132 , a seventh relay  133 , an eighth relay  134 , a fifth driving unit  135 , a sixth driving unit  136 , a seventh driving unit  137 , an eighth driving unit  138 , a third bidirectional thyristor TR 3 , and a fourth bidirectional thyristor TR 4 . 
         [0019]    The control module  14  can comprise a first reset terminal  1 , a first set terminal  2 , a second reset terminal  3 , a second set terminal  4 , a third reset terminal  5 , a third set terminal  6 , a first signal terminal  7 , a second signal terminal  8 , and a third signal terminal  9 . 
         [0020]    A first terminal of the first relay  121  is coupled to a first terminal  101  of the primary power source  10 . A second terminal of the first relay  121  is coupled to a first terminal of the third relay  123 . A second terminal of the first relay  121  is coupled to a first terminal of the first bidirectional thyristor TR 1 . A third terminal and a fourth terminal of the first relay  121  is coupled to the first driving unit  125 . 
         [0021]    A first terminal of the second relay  122  is coupled to a second terminal  102  of the primary power source  10 . A second terminal of the second relay  122  is coupled to a first terminal of the fourth relay  124 . A second terminal of the second relay  122  is coupled to a first terminal of the second bidirectional thyristor TR 2 . A third terminal and a fourth terminal of the second relay  122  are coupled to the first driving unit  125 . 
         [0022]    A second terminal of the third relay  123  is coupled to a first output terminal O 1  of the power switching circuit  200 . The second terminal of the third relay  123  is also coupled to a second terminal of the first bidirectional thyristor TR 1 . A third terminal and a fourth terminal of the third relay  123  are coupled to the second driving unit  126 . 
         [0023]    A second terminal of the fourth relay  124  is coupled to a second output terminal O 2  of the power switching circuit  200 . The second terminal of the fourth relay  124  is also coupled to a second terminal of the second bidirectional thyristor TR 2 . A third terminal and a fourth terminal of the fourth relay  124  are coupled to the second driving unit  126 . 
         [0024]    A control terminal of the first bidirectional thyristor TR 1  is coupled to the third driving unit  127 . A control terminal of the second bidirectional thyristor TR 2  is coupled to the fourth driving unit  128 . 
         [0025]    A first terminal of the fifth relay  131  is coupled to a first output terminal O 1  of the power switching circuit  200 . The first terminal of the fifth relay  131  is also coupled to a first terminal of the third bidirectional thyristor TR 3 . A second terminal of the fifth relay  131  is coupled to a first terminal of the seventh relay  133 . The second terminal of the fifth relay  131  is also coupled to a second terminal of the third bidirectional thyristor TR 3 . A third terminal and a fourth terminal of the fifth driving unit  135  are coupled to the fifth driving unit  135 . 
         [0026]    A first terminal of the sixth relay  132  is coupled to a second output terminal O 2  of the power switching circuit  200 . The first terminal of the sixth relay  132  is also coupled to a first terminal of the fourth bidirectional thyristor TR 4 . A second terminal of the sixth relay  132  is coupled to a first terminal of the eighth relay  134 . The second terminal of the sixth relay  132  is also coupled to a second terminal of the fourth bidirectional thyristor TR 4 . A third terminal and a fourth terminal of the sixth relay  132  is coupled to the fifth driving unit  135 . 
         [0027]    A second terminal of the seventh relay  133  is coupled to a first terminal  111  of the backup power source  11 . A third terminal and a fourth terminal of the seventh relay  133  are coupled to the sixth driving unit  136 . 
         [0028]    A second terminal of the eighth relay  134  is coupled to a second terminal  112  of the backup power source  11 . A third terminal and a fourth terminal of the eighth relay  134  are coupled to the sixth driving unit  136 . 
         [0029]    A control terminal of the third bidirectional thyristor TR 3  is coupled to the seventh driving unit  137 . A control terminal of the fourth bidirectional thyristor TR 4  is coupled to the eighth driving unit  138 . 
         [0030]    The primary power source  10  and the backup power source  11  are both configured to provide a voltage V 1 . The first driving unit  125  receives the voltage V 1 . The first driving unit  125  is also coupled to the first reset terminal  1  and the first set terminal  2  of the control module  14 . 
         [0031]    The second driving unit  126  receives the voltage V 1 . The second driving unit  126  is also coupled to the second reset terminal  3  and the second set terminal  4  of the control module  14 . 
         [0032]    The third driving unit  127  is coupled to the second signal terminal  8  of the control module  14 . The fourth driving unit  128  is coupled to the second signal terminal  8  of the control module  14 . 
         [0033]    The fifth driving unit  135  receives the voltage V 1 . The fifth driving unit  135  is coupled to the first signal terminal  7  of the control module  14 . 
         [0034]    The sixth driving unit  136  receives the voltage V 1 . The sixth driving unit  136  is coupled to the third reset terminal  5  and the third set terminal  6  of the control module  14 . 
         [0035]    The seventh driving unit  137  is coupled to the third signal terminal  9  of the control module  14 . The eighth driving unit  138  is coupled to the third signal terminal  9  of the control module  14 . 
         [0036]    A relay can comprise a contact switch and a coil. 
         [0037]    In the embodiment, a contact switch and a coil of the third relay  123  is coupled in parallel with the first bidirectional thyristor TR 1 . The fourth relay  124  and the second bidirectional thyristor TR 2  are coupled in parallel. The fifth relay  131  and the third bidirectional thyristor TR 3  are coupled in parallel. The sixth relay  132  and the fourth bidirectional thyristor TR 4  are coupled in parallel. 
         [0038]    The first relay  121 , the second relay  122 , the third relay  123 , the fourth relay  124 , the seventh relay  133 , and the eighth relay  134  are latching relays. Latching relays cost less energy to maintain conduction of contact switches. The fifth relay  131  and the sixth relay  132  are non-latching relays. 
         [0039]    When the power switching device  100  starts up, the voltage V 1  is ready to supply current via the first to eighth relays,  121  to  124 ,  131  to  134 . 
         [0040]    At start up, the control module  14  outputs signals through the first reset terminal  1 , the second reset terminal  3 , and the third reset terminal  5  respectively to ensure that the first relay  121 , the second relay  122 , the third relay  123 , the fourth relay  124 , the seventh relay  133 , and the eighth relay  134  are turned off. 
         [0041]    When the power switching device  100  is operating and using the primary power source  10 , the control module  14  turns on the first relay  121 , the second relay  122 , the third relay  123 , the fourth relay  124 . The first terminal  101  of the primary power source  10  is coupled to the output terminal O 1  of the power switching circuit  200 . The second terminal  102  of the primary power source  10  is coupled to the output terminal O 2  of the power switching circuit  200 . The primary power source  10  supplies power for the load  20 . 
         [0042]    After the primary source  10  is coupled to the output terminals, the first bidirectional thyristor TR 1  and the second bidirectional thyristor TR 2  is turn off. 
         [0043]    After the primary source  10  is coupled to the output terminals, the control module  14  outputs control signals through the third set terminal  6  to control the sixth driving unit  136  to turn on the seventh relay  133  and the eighth relay  134 . 
         [0044]    When the power switching device  100  is operating and using the primary power source  10 , the third bidirectional thyristor TR 3 , the fourth bidirectional thyristor TR 4 , the relay  131 , and relay  132  are off. 
         [0045]    When the power switching device  100  operates and needs to switch from the primary power source  10  to the backup power source  11 , the control module  14  turns on the first bidirectional thyristor TR 1  and the second bidirectional thyristor TR 2 , and the control module  14  turns off the first relay  121 , the second relay  122 , the third relay  123 , and the fourth relay  124 . The third relay  123  and the fourth relay  124  are turned off at zero voltage. The primary power source  10  is disconnected from the power switching circuit  200 . Then the control module  14  outputs control signals through the third signal terminal  9  to turn on the third bidirectional thyristor TR 3  and the fourth bidirectional thyristor TR 4 . The control module  14  also outputs control signals through the first signal terminal  7  to turn on the fifth relay  131  and the sixth relay  132 . The control module  14  outputs control signals through the third reset terminal  5  and the third set terminal  6  to control the sixth driving unit  136  to turn on the seventh relay  133  and the eighth relay  134 . The output terminal O 1  of the power switching circuit  200  is coupled to the first terminal  111  of the backup power source  11 . The output terminal O 2  of the power switching circuit  200  is coupled to the second terminal  112  of the backup power source  11 . 
         [0046]    After the backup source  11  is coupled to the output terminals, the third bidirectional thyristor TR 3  and the fourth bidirectional thyristor TR 4  is turned off. 
         [0047]    The control module  14  outputs control signals through the first set terminal  2  to control the first driving unit  125  to turn on the first relay  121  and the second relay  122 . 
         [0048]    When the power switching device  200  is operating and using the backup power source  11 , the first bidirectional thyristor TR 1 , the second bidirectional thyristor TR 2 , the relay  123 , and relay  124  are off. 
         [0049]    Similarly, when the power switching device  1200  is operating and needs to switch from the backup power source  11  to the primary power source  10 , the control module  14  turns off the seventh relay  133  and the eighth relay  134 . The control module  14  turns on the first relay  121 , the second relay  122 , the third relay  123 , and the fourth relay  124 . The power switching circuit  200  is thus coupled to the primary power source  10 . 
         [0050]    The control module  14  turns on the third bidirectional thyristor TR 3  and the fourth bidirectional thyristor TR 4 , and the control module  14  turns off the fifth relay  131 , the sixth relay  132 , the seventh relay  133 , and the eighth relay  134 . The seventh fifth relay  1331  and the eighth sixth relay  1342  are turned off at zero voltage. The backup power source  11  is disconnected from the power switching circuit  200 . Then the control module  14  outputs control signals through the second signal terminal  8  to turn on the first bidirectional thyristor TR 1  and the second bidirectional thyristor TR 2 . The control module  14  also outputs control signals to turn on the third relay  123  and the fourth relay  124 . The control module  14  outputs control signals through the third reset terminal  5  and the third set terminal  6  to control the sixth driving unit  136  to turn on the seventh relay  133  and the eighth relay  134 . The output terminal O 1  of the power switching circuit  200  is coupled to the first terminal  101  of the primary power source  10 . The output terminal O 2  of the power switching circuit  200  is coupled to the second terminal  102  of the primary power source  10 . 
         [0051]    When the power switching device  100  needs to switch from the primary power source  10  to the backup power source  11 , the control module  14  controls the seventh driving unit  137  and the eighth driving unit  138  to turn on the third bidirectional thyristor TR 3  and the fourth bidirectional thyristor TR 4 . The time to conductivity of bidirectional thyristors is in the order of microseconds. The backup power source  11  can be coupled to the power switching circuit  200  to supply power in microseconds. Then the fifth relay  131  and the sixth relay  132  are turned on. The control module  14  controls the seventh driving unit  137  and the eighth driving unit  138  to turn off the third bidirectional thyristor TR 3  and the fourth bidirectional thyristor TR 4 . The first terminal  111  of the backup power source  11  is coupled to the power switching circuit  200  through the seventh relay  133  and the fifth relay  131 . The second terminal  112  of the backup power source  11  is coupled to the power switching circuit  200  through the eighth relay  134  and the sixth relay  132 . 
         [0052]    Similarly, when the power switching device  200  needs to switch from the backup power source  11  to the primary power source  10 , the control module  14  controls the third driving unit  127  and the fourth driving unit  128  to turn on the first bidirectional thyristor TR 1  and the second bidirectional thyristor TR 2 . The time to conductivity of bidirectional thyristors is in the order of microseconds. The backup power source  10  can be coupled to the power switching circuit  200  to supply power in microseconds. Then the third relay  123  and the fourth relay  124  are turned on. The control module  14  controls the third driving unit  127  and the fourth driving unit  128  to turn off the first bidirectional thyristor TR 1  and the second bidirectional thyristor TR 2 . The first terminal  101  of the primary power source  10  is coupled to the power switching circuit  200  through the first relay  121  and the third relay  123 . The second terminal  102  of the primary power source  10  is coupled to the power switching circuit  200  through the second relay  122  and the fourth relay  124   
         [0053]    At power off, the control module  14  outputs signals through the first reset terminal  1 , the second reset terminal  3 , and the third reset terminal  5  respectively to ensure that the first relay  121 , the second relay  122 , the third relay  123 , the fourth relay  124 , the seventh relay  133 , and the eighth relay  134  are turned off. 
         [0054]    While the disclosure has been described by way of example and in terms of the embodiment, it is to be understood that the disclosure is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the range of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.