Patent Publication Number: US-2015076914-A1

Title: Power conversion system and electronic device using same

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a power conversion system and an electronic device using the power conversion system. 
     2. Description of Related Art 
     Electronic devices, such as servers, usually employ an alternating current power supply unit (AC PSU) and a direct current power supply unit (DC PSU) connected to the AC PSU in parallel. When an AC power source supplies AC voltage to the electronic device, the AC PSU converts the AC voltage from the AC power source into a predetermined DC voltage, and outputs the predetermined DC voltage to a load of the electronic device. The DC PSU is in a standby mode when the AC power source normally supplies the AC voltage to the electronic device. The DC PSU receives a DC voltage from a DC power source and converts the DC voltage into the predetermined DC voltage, but does not output the predetermined DC voltage to the load when the DC PSU is in the standby mode. 
     When the AC power source is cut off from supplying the AC voltage to the AC PSU, the DC PSU switches to an operating mode and outputs the predetermined DC voltage to the load. However, because the AC power source normally supplies the AC voltage to the AC PSU, power is wasted keeping the DC PSU in the standby mode. 
     Therefore, what is needed is a power conversion system and an electronic device that can overcome the described limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural diagram illustrating a first embodiment of an electronic device according to the present disclosure. 
         FIG. 2  is a schematic structural diagram illustrating a second embodiment of an electronic device according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to the drawings to describe specific exemplary embodiments of the present disclosure. 
       FIG. 1  is a schematic structural diagram illustrating a first embodiment of an electronic device  1 . The electronic device  1  includes a power conversion system  100  and a load  200  connected to the power conversion system  100 . The power conversion system  100  is configured to connect to a direct current (DC) power source  300  and an alternating current (AC) power source  400 . The DC power source  300  is configured to supply a first DC voltage to the power conversion system  100 . The AC power source  400  is configured to supply AC voltage to the power conversion system  100 . The power conversion system  100  selectively converts either the first DC voltage or the AC voltage into a second DC voltage based on whether the AC power source  400  supplies the AC voltage to the power conversion system  100 , and outputs the second DC voltage to the load  200 . The load  200  operates based on the second DC voltage. The load  200  can be a server, a data center, or a storage, for example. The DC power source  300  can be a plurality of batteries connected in parallel, for example. 
     The power conversion system  100  converts the AC voltage into the second DC voltage when the AC power source  400  supplies the AC voltage to the power conversion system  100 , even though the DC power source  300  simultaneously supplies the first DC voltage to the power conversion system  100 . The power conversion system  100  converts the first DC voltage into the second DC voltage when the AC power source  400  is cut off from supplying the AC voltage to the power conversion system  100 . A range of each of the AC voltage and the first DC voltage can be from about 90 volts (V) to about 264 V. A range of the second DC voltage can be from about 127V to about 375V, in one example. 
     The power conversion system  100  includes a power distribution unit  10  and a first AC power supply unit (PSU)  12  connected between the power distribution unit  10  and the load  200 . The power distribution unit  10  selectively electrically connects the AC power source  400  or the DC power source  300  to the first AC PSU  12  based on whether the AC power source  400  supplies the AC voltage to the power distribution unit  10 , and transmits the AC voltage or the first DC voltage to the first AC PSU  12 . The first AC PSU  12  receives the AC voltage or the first DC voltage, converts the AC voltage or the first DC voltage into the second DC voltage, and outputs the second DC voltage to the load  200 . 
     The power distribution unit  10  includes a detection circuit  101  and a selection circuit  103 . The selection circuit  103  is connected to the detection circuit  101 , the first AC PSU  12 , the DC power source  300 , and the AC power source  400 . The detection circuit  101  detects whether the AC voltage is supplied to the selection circuit  103  and outputs corresponding control signals to the selection circuit  103  based on the detected AC voltage. The selection circuit  103  selectively outputs the AC voltage or the first DC voltage to the first AC PSU  12  based on the corresponding control signals. The corresponding control signals can include a first control signal and a second control signal. The first and second control signals can be digital signals, for example. 
     When the detection circuit  101  detects that the AC voltage is supplied to the selection circuit  103 , the detection circuit  101  outputs the first control signal to the selection circuit  103 . The selection circuit  103  receives the first control signal, selectively electrically connects the AC power source  400  to the first AC PSU  12  based on the first control signal, and transmits the AC voltage to the first AC PSU  12 . In contrast, when the detection circuit  101  detects that the AC voltage is not supplied to the selection circuit  103 , the detection circuit  101  outputs the second control signal to the selection circuit  103 . The selection circuit  103  receives the second control signal, selectively electrically connects the DC power source  300  to the first AC PSU  12  based on the second control signal, and transmits the DC voltage to the first AC PSU  12 . 
     The selection circuit  103  includes a first input  103   a , a second input  103   b , and a conductive pole  103   c . The conductive pole  103   c  includes a first end A and a second end B. The first input  103   a  is connected to the AC power source  400  and receives the AC voltage. The second input  103   b  is connected to the DC power source  300  and receives the first DC voltage. The first end A is selectively connected to either the first input  103   a  or the second input  103   b  based on which one of the first and second control signals is received from the detection circuit  101 . The second end B is connected to the first AC PSU  12 . The detection circuit  101  detects whether the AC voltage is supplied to the first input  103   a  and controls whether the first end A is electrically connected to the first input  103   a  or the second input  103   b  based on the detection. 
     When the detection circuit  101  detects that the AC voltage is supplied to the first input  103   a , the detection circuit  101  outputs the first control signal to the selection circuit  103 . The selection circuit  103  controls the conductive pole  103   c  to electrically connect to the first input  103   a  (shown as a solid arrow in  FIG. 1 ) based on the first control signal. The AC voltage is output to the first AC PSU  12  via the first input  103   a  and the conductive pole  103   c . In contrast, when the detection circuit  101  detects that the AC voltage is not supplied to the first input  103   a , the detection circuit  101  outputs the second control signal to the selection circuit  103 . The selection circuit  103  controls the conductive pole  103   c  to electrically connect to the second input  103   b  (shown as a dashed arrow in  FIG. 1 ). The first DC voltage is output to the first AC PSU  12  via the second input  103   b  and the conductive pole  103   c  based on the second control signal. 
     The first AC PSU  12  includes a full-bridge rectification circuit  121 , a resistor R, and a capacitor C. The full-bridge rectification circuit  121  includes a first input I1, a second input  12 , a first output O1, and a second output O2. The resistor R and the capacitor C are connected between the first output O1 and the second output O2 in parallel. The first input I1 is connected to the second end B of the conductive pole  103   c  to receive the AC voltage or the first DC voltage. The second input  12  is connected to ground. The first output O1 is connected to the load  200 . The second output O2 is connected to ground. 
     The full-bridge rectification circuit  121  includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. A cathode of the first diode D1 is connected to an anode of the second diode D2. A first node N1 is defined between the first diode D1 and the second diode D2. The first node N1 is connected to the first input I1. A cathode of the third diode D3 is connected to an anode of the fourth diode D4. A second node N2 is defined between the third diode D3 and the fourth diode D4. The second node N2 is connected to the second input  12 . A cathode of the second diode D2 is connected to an anode of the fourth diode D4. A third node N3 is defined between the second diode D2 and the fourth diode D4. The third node N3 is connected to the first output O1. An anode of the first diode D1 is connected to an anode of the third diode D3. A fourth node N4 is defined between the first diode D1 and the third diode D3. The fourth node N4 is connected to the second output O2. 
     The full-bridge rectification circuit  121  receives the AC voltage or the first DC voltage, converts the AC voltage or first DC voltage into the second DC voltage, and outputs the second DC voltage to the load  200 . A capacitance of the capacitor C can be about 4700 microfarads (uF), for example. 
     Since the power conversion system  100  detects whether the AC voltage is inputted, the power conversion system  100  selectively outputs the AC voltage or the first DC voltage to the first AC PSU  12  based on the detection. Accordingly, the first AC PSU  12  converts the AC voltage or the first DC voltage into the second DC voltage and outputs the second DC voltage to the load  200 . Thus, the power conversion system  100  need not employ a separate DC PSU as required in the prior art, and the first AC PSU  12  remains in an operating state whether the AC power source  400  is cut off or not. As a result, efficiency of supplying power to the load  200  is improved. 
       FIG. 2  is a schematic structural diagram illustrating a second embodiment of an electronic device  2 . The electronic device  2  includes a power conversion system  500  and a load  600  connected to the power conversion system  500 . The electronic device  2  differs from the electronic device  1  of the first embodiment in that the power conversion system  500  differs from the power conversion system  100  of the electronic device  1 . The load  600  can be identical with the load  200  of the electronic device  1 . 
     The power conversion system  500  includes a power distribution unit  50 , a first AC PSU  52 , and at least one second AC PSU  54 . A number of the second AC PSU  54  can be N+1, wherein N is an integer more than one. The first AC PSU  52  and the at least one second AC PSU  54  are connected between the power distribution unit  50  and the load  600  in parallel. The first AC PSU  52  is substantially identical to the first AC PSU  12  of the power conversion system  100 . In the embodiment, the at least one second AC PSU  54  can be identical to the first AC PSU  52 . The second AC PSU  54  is connected between a second end D of a conductive pole  503   c  of a selection circuit  503  and the load  600 . 
     The power distribution unit  50  selectively outputs the AC voltage from the AC power source  400  or the first DC voltage from the DC power source  300  to the first AC PSU  52  and the second AC PSU  54 , based on whether the AC power source  400  supplies the AC voltage to the power distribution unit  50 . The first AC PSU  52  and the second AC PSU  54  receive the AC voltage from the AC power source  400  or the first DC voltage from the DC power source  300 , convert the AC voltage or the first DC voltage into the second DC voltage, and output the second DC voltage to the load  600 . 
     Since the power conversion system  500  further includes the second AC PSU  54  connected to the first AC PSU  52  in parallel, an amount of current passing through the first AC PSU  52  is reduced. Accordingly, power consumed by the first AC PSU  52  is reduced. As a result, the first AC PSU  52  generates less heat. 
     It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the present disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments.