Abstract:
An AC-AC power source conversion device, comprising a rectifier circuit ( 10 ), an active power factor correction circuit ( 20 ), an automatic charge pumping circuit ( 30 ) and an inverter circuit ( 40 ), wherein the rectifier circuit is connected to an AC power source ( 100 ), receives the electric energy therefrom, and then converts the same into the DC electric energy for output; the active power factor correction circuit is connected to the rectifier circuit, receives the electric energy therefrom, and outputs the same after promoting a power factor; the automatic charging pumping circuit is connected to the active power factor correction circuit, receives the electric energy therefrom, and then adjusts and outputs same; and the inverter circuit is connected to the automatic charge pumping circuit and a load ( 200 ), receives the electric energy therefrom, converts same into the AC electric energy, and then outputs same to the load.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to power conversion, in particular to an AC-AC power source conversion device and the conversion method thereof. 
       BACKGROUND 
       [0002]    A conventional AC-AC power conversion device usually has a rectifier circuit, an output capacitor and an inverter so as to convert an AC power source into a DC power source; the output capacitor is connected to the output side of the rectifier circuit in parallel; the inverter is connected to the output capacitor, and then connected to a load. 
         [0003]    When the AC-AC power conversion device is in operation, the phase of the output voltage of the AC power source tends to be different from the phase of the input current of the AC power source, which will result in low power factor and serious total harmonic distortion. In addition, the rectifier circuit will not charge the output capacitor unless the output voltage of the DC electric energy outputted from the rectifier circuit is higher than the voltage of the output capacitor; accordingly, the charging time of the output capacitor will be reduced, and the on time of the diode in the rectifier circuit will also be reduced to further increase the peak value of the turn-on current, which will not only distort the waveform of the input current and reduce the power factor, but also will further influence the current response speed of the inverter; for the reason, the AC electric energy outputted to the load will be seriously distorted. 
         [0004]    Therefore, the above conventional AC-AC power source conversion device still has a lot of shortcomings and defects in structure and use needed to be further improved. In order to solve the above problems, a lot of circuit designers have kept trying hard to find a solution, but a proper solution has yet to be successfully developed until now; besides, the currently available products have no proper structure to solve the above problems; thus, how to create a novel AC-AC power source conversion device and the conversion method thereof not only have become an important R&amp;D object, but also have become the most important problem to be solved in the world. 
       SUMMARY 
       [0005]    In view of above, the object of the present invention is to provide an AC-AC power source conversion device and the conversion method thereof to overcome the shortcomings of the currently available AC-AC power source conversion devices; the technical problems solved by the present invention are not only to achieve high power factor, but also achieve swift response and low-ripple output voltage. 
         [0006]    The object of the present invention can be realized by adopting the following technical schemes. The present invention provides an AC-AC power source conversion device for converting the electric energy of an AC power source and then supply the electric energy to a load; the AC-AC power source conversion device includes a rectifier circuit, an active power factor correction circuit, an automatic charge pumping circuit and an inverter circuit. More specifically, the input side of the rectifier circuit is connected to the AC power source for receiving the electric energy of the AC power source, converting the electric energy into the DC electric energy, and outputting the DC electric energy from the output side of the rectifier circuit; besides, the output side has a positive terminal and a negative terminal. The active power factor correction circuit is connected to the output side of the rectifier circuit for receiving the DC electric energy of the rectifier circuit, increasing the power factor of the DC electric energy and outputting the DC electric energy; the active power factor correction circuit includes a first diode, where the cathode of the first diode is connected to the positive terminal; a first capacitor, where one end of the first capacitor is connected to the anode of the first diode; an electronic switch, where one end of the electric switch is connected to the other end of the first capacitor, and the other end of the electronic switch being connected to the negative terminal; a first inductor, where one end of the first inductor is connected to the junction of the cathode of the first diode and the positive terminal, and the other end of the first inductor is connected to the junction of the first capacitor and the electronic switch; a second diode, where the anode of the second diode is connected to the junction of the electronic switch and the negative terminal; a second inductor, where one end of the second inductor is connected to the junction of the anode of the first diode and the first capacitor, and the other end of the second inductor is connected to the cathode of the second diode. The automatic charge pumping circuit is connected to the active power factor correction circuit for receiving the DC electric energy outputted from the active power factor correction circuit, adjusting the DC electric energy and outputting the DC electric energy; the automatic charge pumping circuit includes a third diode, where the anode of the third diode is electrically connected to the junction of the cathode of the second diode and the second inductor, and the cathode of the third diode is electrically connected to the junction of the second inductor, the anode of the first diode and the first capacitor; a second capacitor, where one end of the second capacitor is connected to the cathode of the third diode; a third inductor, where one end of the third inductor is connected to the other end of the first capacitor, and the other end of the third inductor is electrically connected to the junction of the cathode of the third diode and the second capacitor; an equivalent capacitor, where one end of the equivalent capacitor is connected to the junction of the second capacitor and the third inductor, and the other end of the equivalent capacitor is connected to the junction of the anode of the third diode, the cathode of the second diode and the second inductor; the inverter circuit is electrically connected to the equivalent capacitor of the automatic charge pumping circuit, and connected to the load for receiving the DC electric energy outputted from the automatic charge pumping circuit, and converting the DC electric energy into an AC electric energy with a predetermined frequency, and then outputting the AC electric energy with the predetermined frequency to the load. 
         [0007]    The object of the present invention can be further realized by adopting the following technical measures. 
         [0008]    Regarding the aforementioned AC-AC power source conversion device, the equivalent capacitor is composed of a third capacitor and a fourth capacitor, and the third capacitor is connected to one end of the fourth capacitor; the inverter circuit includes a first switch and a second switch, and the first switch is connected to one end of the second switch; besides, the third capacitor and the other end of the first switch are connected to the junction of the second capacitor and the third inductor, and the fourth capacitor and the other end of the second switch are connected to the junction of the anode of the third diode, the cathode of the second diode and the second inductor; moreover, one end of the load is connected to the junction of the third capacitor and the fourth capacitor, and the other end of the load is connected to the junction of the first switch and the second switch. 
         [0009]    Regarding the aforementioned AC-AC power source conversion device, the inverter circuit includes a first switch, a second switch, a third switch and a fourth switch; the first switch is connected to one end of the third switch, and the second switch is connected to one end of the fourth switch; besides, the other end of the first switch and the other end of the second switch are connected to the junction of the equivalent capacitor, the second capacitor and the third inductor, and the other end of the third switch and the other end of the fourth switch are connected to the junction of the equivalent capacitor, the anode of the third diode, the cathode of the second diode and the second inductor; moreover, one end of the load is connected to the junction of the first switch and the third switch, and the other end of the load is connected to the junction of the second switch and the fourth switch. 
         [0010]    Regarding the aforementioned AC-AC power source conversion device, the automatic charge pumping circuit further includes a fourth diode; one end of the fourth diode is connected to the junction of the cathode of the third diode and the second capacitor, and the other end of the fourth diode is connected to the third inductor, whereby the third inductor is electrically connected to the junction of the cathode of the third diode and the second capacitor via the fourth diode. 
         [0011]    Regarding the aforementioned AC-AC power source conversion device, the anode of the fourth diode is connected to the junction of the cathode of the third diode and the second capacitor, and the cathode of the fourth diode is connected to the third inductor. 
         [0012]    Regarding the aforementioned AC-AC power source conversion device, the automatic charge pumping circuit further includes a fifth diode; one end of the fifth diode is connected to the junction of the second inductor, the anode of the first diode and the first capacitor, and the other end of the fifth diode is connected to the junction of the cathode of the third diode and the second capacitor, whereby the cathode of the third diode and the second capacitor are electrically connected to the junction of the second inductor, the anode of the first diode and the first capacitor via the fifth diode. 
         [0013]    Regarding the aforementioned AC-AC power source conversion device, the anode of the fifth diode is connected to the junction of the second inductor, the anode of the first diode and the first capacitor, and the cathode of the fifth diode is connected to the junction of the cathode of the third diode and the second capacitor. 
         [0014]    The object of the present invention can be further realized by adopting the following technical schemes. According to the above design, the conversion method of the AC-AC power source conversion device includes the following steps: 
         [0015]    A. turning on the electronic switch to charge the first inductor by the DC electric energy outputted from the rectifier circuit, and charging the second inductor by the first capacitor, and charging the equivalent capacitor by the second capacitor and the third inductor to make the equivalent capacitor power the load via the inverter circuit; 
         [0016]    B. turning off the electronic switch to stop the DC electric energy outputted from the rectifier circuit to charge the first capacitor by the first inductor, and change the third inductor, the second capacitor and the equivalent capacitor by the second inductor to make the equivalent capacitor keep powering the load via the inverter circuit; 
         [0017]    C. stopping the second inductor from charging the third inductor, the second capacitor and the equivalent capacitor to turn off the third diode, and make the third inductor charge the second capacitor so as to reverse the voltage across the second capacitor and make the equivalent capacitor keep powering the load via the inverter circuit; 
         [0018]    D. turning on the third diode to reverse the voltage across the second capacitor and the voltage across the third inductor, and charging the equivalent capacitor to make the equivalent capacitor keep powering the load via the inverter circuit. 
         [0019]    The object of the present invention can be further realized by adopting the following technical measures. 
         [0020]    Regarding the aforementioned conversion method, wherein the method further includes a step after the step D, and the step is to repeat executing the step A to the step D. 
         [0021]    Regarding the aforementioned conversion method, wherein after the step B, the first inductor stops charging the first capacitor to turn off the first diode. 
         [0022]    Regarding the aforementioned conversion method, wherein during the step B, the second inductor charges the equivalent capacitor via the resonant circuit formed by the second capacitor and the third inductor. 
         [0023]    Regarding the aforementioned conversion method, wherein after the second capacitor and the third inductor form the resonant circuit in the step C, the third inductor charges the second capacitor to reverse the polarity of the voltage across the second capacitor; then, when the voltage across the third inductor is higher than the voltage across the equivalent capacitor, the third diode is turned on, and then the method proceeds to the step D. 
         [0024]    Compared with prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical schemes, the AC-AC power source conversion device and the conversion method thereof in accordance with the present invention have at least the following advantages and beneficial effects: via the above design, the present invention can not only increase the power factor during the power conversion, but also can achieve swift response and low-ripple output voltage. 
         [0025]    Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is a circuit diagram of a preferred embodiment of an AC-AC power source conversion device in accordance with the present invention; 
           [0027]      FIG. 2A ,  FIG. 2B ,  FIG. 3A ,  FIG. 3B ,  FIG. 4A ,  FIG. 4B ,  FIG. 5A ,  FIG. 5B  are the equivalent circuit diagram of the steps; 
           [0028]      FIG. 6  is a circuit diagram of another preferred embodiment of an AC-AC power source conversion device in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The technical content of the present invention will become apparent by the detailed description of the following embodiments and the illustration of related drawings as follows. 
         [0030]    Please refer to  FIG. 1 , which is a preferred embodiment of an AC-AC power source conversion device in accordance with the present invention; the AC-AC power source conversion device can convert the electric energy of an AC power source  100  and then supply the electric energy to a load  200 . The AC-AC power source conversion device includes a rectifier circuit  10 , an active power factor correction circuit  20 , an automatic charge pumping circuit  30  and an inverter circuit  40 , wherein: 
         [0031]    In the embodiment, the rectifier circuit  10  is a bridge rectifier, and its input side is connected to the AC power source  100  for receiving the electric energy of the AC power source  100 , converting the electric energy into the DC electric energy, and outputting the DC electric energy from its output side; besides, its output side has a positive terminal  12  and a negative terminal  14  according to the polarity of the DC electricity energy outputted. 
         [0032]    The active power factor correction circuit  20  is connected to the output side of the rectifier circuit  10  for receiving the DC electric energy of the rectifier circuit  10 , increasing the power factor of the DC electric energy and then outputting the DC electric energy; the active power factor correction circuit includes 2 diodes (the first diode D 1  and the second diode D 2 ), a capacitor (the first capacitor C 1 ),  2  inductors (the first inductor L 1  and the second inductor L 2 ) and an electronic switch SW. The connection relations of the above components are as follows: 
         [0033]    The cathode of the first diode D 1  is connected to the positive terminal  12 . 
         [0034]    One end of the first capacitor C 1  is connected to the anode of the first diode D 1 . 
         [0035]    One end of the electric switch SW is connected to the other end of the first capacitor C 1 , and the other end thereof is connected to the negative terminal  14 . 
         [0036]    One end of the first inductor L 1  is connected to the junction of the cathode of the first diode D 1  and the positive terminal  12 , and the other end of the first inductor L 1  is connected to the junction of the first capacitor C 1  and the electronic switch SW. 
         [0037]    The anode of the second diode D 2  is connected to the junction of the electronic switch SW and the negative terminal  14 . 
         [0038]    One end of the second inductor L 2  is connected to the junction of the anode of the first diode D 1  and the first capacitor C 1 , and the other end thereof is connected to the cathode of the second diode D 2 . 
         [0039]    The automatic charge pumping circuit  30  is connected to the active power factor correction circuit  20  for receiving the DC electric energy outputted from the active power factor correction circuit  20 , adjusting the DC electric energy and outputting the DC electric energy, which includes 3 diodes (the third diode D 3 , the fourth diode D 4  and the fifth diode D 5 ),  3  capacitors (the second capacitor C 2 , the third capacitor C 3  and the fourth capacitor C 4 ) and an inductor (the third inductor L 3 ). The connection relations of the above components are as follows: 
         [0040]    The anode of the fifth diode D 5  is connected to the junction of the second inductor L 2 , the anode of the first diode D 1  and the first capacitor C 1 . 
         [0041]    The anode of the third diode D 3  is electrically connected to the junction of the cathode of the second diode D 2  and the second inductor L 2 , and its cathode is electrically connected to the cathode of the fifth diode D 5  so as to be electrically connected to the junction of the anode of the first diode D 1 , the second inductor L 2  and the first capacitor C 1  via the fifth diode D 5 . 
         [0042]    The anode of the fourth diode D 4  is connected to the junction of the cathode of the third diode D 3 , the cathode of the fifth diode D 5  and the second capacitor C 2 . 
         [0043]    One end of the third inductor D 3  is connected to the other end of the first capacitor C 1 , and the other end thereof is connected to the cathode of the fourth diode D 4  so as to be electrically connected to the junction of the cathode of the third diode D 3 , the cathode of the fifth diode D 5  and the second capacitor C 2 . 
         [0044]    The third capacitor C 3  is connected to one end of the fourth capacitor C 4 , and the other end of the third capacitor C 3  is connected to the junction of the second capacitor C 2  and the third inductor L 3 ; the other end of the fourth capacitor C 4  is connected to the junction of the anode of the third diode D 3 , the cathode of the second diode D 2  and the second inductor L 2 . 
         [0045]    The inverter circuit  40  is electrically connected to the automatic charge pumping circuit  30 , and connected to the load  200  for receiving the DC electric energy outputted from the automatic charge pumping circuit  30 , and converting the DC electric energy into the AC electric energy with a predetermined frequency, and then outputting the AC electric energy with the predetermined frequency to the load  200 . In the embodiment, the inverter circuit  40  is of half-bridge structure and includes a first switch S 1  and a second switch S 2 , and the first switch S 1  is connected to one end of the second switch S 2 ; besides, the other end of the first switch S 1  is connected to the junction of the second capacitor C 2  and the third capacitor C 3  and the third inductor L 3 , and the other end of the second switch S 2  is connected to the junction of the fourth capacitor C 4 , the anode of the third diode D 3 , the cathode of the second diode D 2  and the second inductor L 2 . In the embodiment, the specifications of the capacitors C 1 ˜C 4 , the inductors L 1 ˜L 3 , the input voltage, the electronic switch SW. the switching frequency of the switches S 1 , S 2  and the load  200  are as shown in the following table: 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 First inductor L1 
                 300 
                 μH 
               
               
                   
                 Second inductor L2 
                 300 
                 μH 
               
               
                   
                 Third inductor L3 
                 1000 
                 mH 
               
               
                   
                 First capacitor C1 
                 200 
                 μF 
               
               
                   
                 Second capacitor C2 
                 8 
                 nF 
               
               
                   
                 Third capacitor C3 
                 100 
                 μF 
               
               
                   
                 Fourth capacitor C4 
                 100 
                 μF 
               
               
                   
                 Input voltage Vin 
                 200 
                 Vrms 
               
               
                   
                 Switching frequency of electronic switch SW 
                 100 
                 KHz 
               
               
                   
                 Switching frequency of switches S1, S2 
                 200 
                 Hz 
               
               
                   
                 Load resistance 
                 100 
                 Ω 
               
               
                   
                   
               
             
          
         
       
     
         [0046]    By means of the above structure design and specification, one end of the load  200  can be connected to the junction of the third capacitor C 3  and the fourth capacitor C 4 , and the other end of the load  200  can be connected to the junction of the first switch S 2  and the second switch S 2 ; then, the above structure can not only increase the power factor, but also can achieve swift response and low-ripple output voltage by using the following conversion method; the method includes the following steps: 
         [0047]    A. please refer to  FIG. 2A  and  FIG. 2B , turning on the electronic switch SW to charge the first inductor L 1  by the DC electric energy outputted from the rectifier circuit  10 , and charging the second inductor L 2  by the first capacitor C 1 , and charging the third capacitor C 3  and the fourth capacitor C 4  by the second capacitor C 2  and the third inductor L 3  to make the third capacitor C 3  and the fourth capacitor C 4  power the load via the inverter circuit  40 . In addition, if the operation of the AC-AC power source conversion device is during the positive alternation status, the second switch S 2  is turned on; in the meanwhile, the fourth capacitor C 4  powers the load  200 ; the equivalent circuit is as shown in  FIG. 2A . If the operation of the AC-AC power source conversion device is during the negative alternation status, the first switch S 1  is turned on; in the meanwhile, the third capacitor C 3  powers the load  200 ; the equivalent circuit is as shown in  FIG. 2B . 
         [0048]    B. please refer to  FIG. 3A  and  FIG. 3B , turning off the electronic switch SW to stop the DC electric energy outputted from the rectifier circuit  10  to charge the first capacitor C 1  by the first inductor L 1 , and make the second inductor L 2  change the third inductor L 3  and the second capacitor C 2 ; then, making the second inductor L 2  charge the third capacitor C 3  and the fourth capacitor C 4  via the resonant circuit formed by the second capacitor C 2  and the third inductor L 3  so as to make the third capacitor C 3  and the fourth capacitor C 4  keep powering the load  200  via the inverter circuit  40  according to the positive alternation status or the negative alternation status. 
         [0049]    C. please refer to  FIG. 4A  and  FIG. 4B , after the first inductor L 1  stops outputting electricity energy, the first diode D 1  is turned off; after the second inductor stops outputting electric energy, the fifth diode D 5  is turned off. Meanwhile, the second capacitor C 2  and the third inductor L 3  form a resonant circuit to make the third inductor L 3  charge the second capacitor C 2  so as to reverse the polarity of the voltage across the second capacitor C 2 , and make the third capacitor C 3  and the fourth capacitor C 4  keep powering the load  200  via the inverter circuit  40  according to the positive alternation status or the negative alternation status. 
         [0050]    D. when the voltage across the third inductor C 3  is higher than the total voltage across the third capacitor C 3  and the fourth capacitor C 4 , the third diode D 3  is turned on to reverse the voltage across the second capacitor C 2  and the voltage across the third inductor L 3  of the step C to charge the third capacitor C 3  and the fourth capacitor C 4  in order to make the third capacitor C 3  and the fourth capacitor C 4  keep powering the load  200  via the inverter circuit  40  according to the positive alternation status or the negative alternation status. 
         [0051]    After each of the step A˜step D is executed for one time, it means one operation cycle is finished. Thus, when the AC-AC power source conversion device keeps being in operation, the step A˜step D will be repeatedly executed after the step D until the AC-AC power source conversion device is turned off. 
         [0052]    By means of the above design of the AC-AC power source conversion device, in each operation cycle, the voltage across the second capacitor C 2  can automatically provide negative potential to turn on the third diode D 3  to completely change the circuit structure, which can achieve swift response and low-ripple output voltage; in the meanwhile, the switching of the electronic switch SW can increase the power factor. 
         [0053]    Moreover, the design of the fourth diode D 4  and the fifth diode D 5  can further effectively prevent the backflow of the circuit from influencing the operations of the active power factor correction circuit  20  and the automatic charge pumping circuit  30  respectively, which can make the whole circuit more stable so as to better the power conversion and the ripple voltage suppression effect of the AC-AC power source conversion device. Of course, in practice, the objects of increasing the power conversion efficiency and the ripple voltage suppression effect can be still achieved without the fourth diode D 4  and the fifth diode D 5 . 
         [0054]    Furthermore, the AC-AC power source conversion device in accordance with the present invention can not only be applied to the half-bridge type inverter circuit  40 , but also can be applied to the full-bridge type inverter circuit  50  shown in  FIG. 6 ; the difference between them is that the full-bridge type inverter circuit  50  has the first switch S 3 ˜the fourth switch S 6 , and the third capacitor C 3  and the fourth capacitor C 4  serve as the equivalent capacitors; their connection relations are as follows: 
         [0055]    The first switch S 3  is connected to one end of the third switch S 5 , and the second switch S 4  is connected to one end of the fourth switch S 6 . Besides, the first switch S 3  and the other end of the second switch S 4  are connected to the junction of the equivalent capacitor C 5 , the second capacitor C 2  and the third inductor L 3 , and the third switch S 5  and the other end of the fourth switch S 6  are connected to the junction of the equivalent capacitor C 5 , the anode of the third diode D 3 , the cathode of the second diode D 2  and the second inductor L 2 . 
         [0056]    By means of the above structure design, one end of the load  200  can be connected to the junction of the first switch S 3  and the third switch S 5 , and the other end thereof can be connected to the junction of the second switch S 4  and the fourth switch S 6 ; the above circuit structure integrated with the aforementioned conversion method can also achieve high power factor, swift response and low-ripple output voltage. 
         [0057]    It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.