Abstract:
A rectifier circuit includes a three-phase alternating current (AC) voltage, a first rectifier unit, a second rectifier unit, a third rectifier unit, a first voltage output terminal, a second voltage output terminal, a first energy storing circuit and a second energy storing circuit. The three-phase AC voltage generates a first AC voltage, a second AC voltage, and a third AC voltage, and outputs them to the first rectifier circuit, a second rectifier circuit, and a third rectifier circuit correspondingly. The first energy storing circuit and the second storing circuit are connected in series and are coupled between the first voltage output terminal and the second voltage output terminal, to drive a load. In a positive period of each AC voltage, the second energy storing circuit is charged by each rectifier unit. In a negative period of each AC voltage, the first energy storing circuit is charged by each rectifier unit.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to voltage rectifying technologies, and more particularly to a rectifier circuit having a power factor correction function and an electronic device using the same. 
         [0003]    2. Description of Related Art 
         [0004]    When an alternating current (AC) voltage is converted into a direct current (DC) voltage, a converter is used. A boost circuit can be used as a converter. A DC voltage generated by the converter can be too great that the DC voltage cannot be directly used by an electronic device. Thus, a transformer is needed to convert the DC voltage into a suitable voltage for the electronic device. However, the circuit will require more space to place the transformer. 
         [0005]    Therefore, what is needed is to provide a means that can overcome the above-described limitations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The components in the drawings are not necessarily drawn to scale, the emphasis instead placed upon clearly illustrating the principles of at least one embodiment. In the drawings, like reference numerals designate corresponding parts throughout the various views, and all the views are schematic. 
           [0007]      FIG. 1  is a circuit diagram of a rectifier circuit according to one embodiment of the present disclosure; the rectifier circuit includes a signal generating unit, a first switch, and a three-phase AC power supply. 
           [0008]      FIG. 2  is a block diagram of the signal generating unit of  FIG. 1 . 
           [0009]      FIG. 3  is a circuit diagram of the first switch of  FIG. 1 . 
           [0010]      FIG. 4  is a waveform diagram of a first AC voltage, a second AC voltage, and a third AC voltage generated by the three-phase AC power supply of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” 
         [0012]      FIG. 1  is a circuit diagram of a rectifier circuit  100  according to one embodiment of the present disclosure; the rectifier circuit includes a signal generating unit, a first switch, and a three-phase AC power supply. The rectifier circuit  100  is adapted to provide a driving voltage to a load  200 . The rectifier circuit  100  includes a three-phase AC power supply  10 , a first rectifier unit  20 , a second rectifier unit  30 , a third rectifier unit  40 , a first energy storing circuit  50 , a second energy storing circuit  60 , a first voltage output terminal  70 , a second voltage output terminal  80 , and a signal generating unit  90  (see  FIG. 2 ) 
         [0013]    The three-phase AC power supply  10  includes a first AC voltage output terminal  11 , a second AC voltage output terminal  12 , a third AC voltage output terminal  13 , and a common terminal  14 . The three-phase AC power supply  10  generates a first AC voltage, a second AC voltage, and a third AC voltage. The first AC voltage, the second AC voltage, and the third AC voltage have a same frequency. Phase differences between the first AC voltage and the second AC voltage, the second AC voltage and the third AC voltage, and the third AC voltage and the first AC voltage, are each 120 degrees (in one example), as shown in  FIG. 4 . The first AC voltage is output via the first AC voltage output terminal  11  and the common terminal  14 . The second AC voltage is output via the second AC voltage output terminal  12  and the common terminal  14 . The third AC voltage is output via the third AC voltage output terminal  13  and the common terminal  14 . The first AC voltage, the second AC voltage, and the third AC voltage each has a periodic and sinusoidal waveform. The sinusoidal waveform includes a positive period and a negative period. A voltage value of the AC voltage is greater than zero in the positive period, and less than zero in the negative period. 
         [0014]    The first rectifier unit  20  receives the first AC voltage and discharges to the first energy storing circuit  50  and the second energy storing circuit  60 . The second rectifier unit  30  receives the second AC voltage and discharges to the first energy storing circuit  50  and the second energy storing circuit  60 . The third rectifier unit  40  receives the third AC voltage and discharges to the first energy storing circuit  50  and the second energy storing circuit  60 . The first energy storing circuit  50  and the second energy storing circuit  60  store energy, and converts the energy into a DC voltage. The DC voltage serves as a driving voltage for the load  200 . 
         [0015]    Referring to  FIG. 2 , the signal generating unit  90  includes twelve terminals. The twelve terminals are a first terminal  91 , a second terminal  92 , a third terminal  93 , a fourth terminal  94 , a fifth terminal  95 , a sixth terminal  96 , a seventh terminal  97 , an eighth terminal  98 , a ninth terminal  99 , a tenth terminal  910 , an eleventh terminal  911 , and a twelfth terminal  912 . The signal generating unit  90  generates a first control signal, a second control signal, a third control signal, a fourth control signal, a fifth control signal, sixth control signal, a seventh control signal, an eighth control signal, a ninth control signal, a tenth control signal, an eleventh control signal, and a twelfth control signal. The control signals are output via the corresponding terminals. For example, the first control signal is output via the first terminal  91 , the second control signal is output via the second terminal  92 , and so on. The twelve control signals are periodic signals. In the embodiment, the control signals are pulse width modulation (PWM) signals. Duty ratio of the PWM signals can be modulated. Frequencies of the twelve control signals are greater than a frequency of the AC voltages. In the embodiment, the frequencies of the twelve control signals are integer times greater than the frequency of the AC voltages. Each of the control signals includes a first half period and a second half period. For example, a voltage of the first half period of the control signals is greater than zero, and a voltage of the second half period of the control signals is less than zero. In the embodiment, each first half period of the twelve control signals occurs at the same time, and each second half period of the twelve control signals occurs at the same time. 
         [0016]    The first rectifier unit  20 , the second rectifier unit  30 , and the third rectifier unit  40  have substantially the same electronic components and connections. Hereafter, the first rectifier unit  20  will be described. 
         [0017]    Referring to  FIG. 3 , the first rectifier unit  20  includes a first switch  21 , a second switch  22 , a first energy storing sub-unit  23 , a third switch  24 , a first unidirectional circuit  25 , a second unidirectional circuit  26 , and a fourth switch  27 . In this embodiment, the first switch  21 , the second switch  22 , the third switch  24 , and the fourth switch  27  are N-channel metal-oxide semiconductor field-effect transistors (NMOSFET). The first energy storing sub-unit  23  is an inductor. 
         [0018]    The first switch  21  includes a first gate  211 , a first drain  212 , and a first source  213 . The first gate  211  receives the first control signal output from the first terminal  91  and controls the first switch  21  to switch on or off according to the first control signal. The first drain  212  is electronically coupled to the first AC voltage output terminal  11  and the first drain  212  serves as an input terminal of the first rectifier unit  20 . The second switch  22  includes a second gate  221 , a second drain  222 , and a second source  223 . The second gate  221  receives the second control signal output from the second terminal  92  and controls the second switch  22  to switch on or off according to the second control signal. The second source  223  is electronically coupled to the first source  213 . The second switch  22  switches on when the first switch  21  switches on, and the second switch  22  switches off when the first switch  21  switches off under control of the second control signal. 
         [0019]    The first energy storing sub-unit  23  is connected between the second source  222  and a node  231 . The node  231  is between the first energy storing circuit  50  and the second energy storing circuit  60 . The third switch  24  includes a third gate  241 , a third drain  242 , and the third source  243 . The third gate  241  receives the third control signal output from the third terminal  93  and controls the third switch  24  to switch on or off according to the third control signal. The third source  243  is electronically coupled to a node  232 . The node  232  is between the second drain  222  and the first energy storing sub-unit  23 . The third drain  242  is electronically connected to the first voltage output terminal  70  via the first unidirectional circuit  25 . In the embodiment, the first unidirectional circuit  25  is a diode, and includes a first anode  251  and a first cathode  252 . The first unidirectional circuit  25  turns on when a voltage of the second anode  251  is greater than a voltage of the second cathode  252 , and turns off when the voltage of the second anode  251  is less than the voltage of the second cathode  252 . The first anode  251  is electronically connected to the third drain  242 , and the first cathode  252  is electronically connected to the first voltage output terminal  70 . 
         [0020]    In the embodiment, the second unidirectional circuit  26  includes a second anode  261  and a second cathode  262 . The second unidirectional circuit  26  turns on when a voltage of the second anode  261  is greater than a voltage of the second cathode  262 , and turns off when the voltage of the second anode  261  is less than the voltage of the second cathode  262 . The second cathode  262  is electronically connected to the node  232 . The fourth switch  27  includes a fourth gate  271 , a fourth drain  272 , and a fourth source  273 . The fourth gate  271  receives the fourth control signal output from the fourth terminal  94  and controls the fourth switch  27  to switch on or off according to the fourth control signal. The fourth drain  272  is electronically connected to the second anode  261 . The fourth source  273  is electronically connected to the second voltage output terminal  80 . 
         [0021]    The conversion of the first AC voltage into a first DC voltage is described below. 
         [0022]    When the first AC voltage is in the positive period, the first switch  21  switches on during the first half period of the first control signal, and switches off during the second half period of the first control signal. The second switch  22  switches on when the first switch  21  switches on, and switches off when the first switch  21  switches off. That is, the second switch  22  switches on during the first half period of the second control signal, and switches off during the second half period of the second control signal. The third switch  24  switches off during the first half period of the third control signal and during the second half period of the third control signal. The fourth switch  27  switches off during the first half period of the fourth control signal, and switches on during the second half period of the fourth control signal. When the first AC voltage is in the positive period, the first energy storing sub-circuit  23  stores energy during the first half period of the control signals. During the second half period of the control signals, the first energy storing sub-circuit  23  discharges to the second energy storing circuit  60 , and the second energy storing circuit  60  stores energy. 
         [0023]    When the first AC voltage is in the negative period, the first switch  21  switches on during the first half period of the first control signal, and switches off during the second half period of the first control signal. The second switch  22  switches on when the first switch  21  switches on, and the second switch  22  switches off when the first switch  21  switches off. That is, the second switch  22  switches on during the first half period of the second control signal, and the second switch  22  switches off during the second half period of the second control signal. The third switch  24  switches off during the first half period of the third control signal, and the third switch  24  switches on during the second half period of the third control signal. The fourth switch  27  switches off during the first half period and the second half period of the fourth control signal. When the first AC voltage is in the negative period, the first energy storing sub-unit  23  stores energy during the first half period of the control signals. During the second half period of the control signals, the first energy storing sub-circuit  23  discharges to the first energy storing circuit  50 , and the first energy storing circuit  50  stores energy. 
         [0024]    The first energy storing circuit  50  and the second energy storing circuit  60  are fully charged after a few periods of the first AC voltage. A time to fully charge the first energy storing circuit  50  and the second energy storing circuit  60  relates to a voltage value of the AC voltage, and a capacity of the first energy storing circuit  50  and the second energy storing circuit  60 . 
         [0025]    When the first energy storing circuit  50  and the second energy storing circuit  60  are fully charged, the principle of the rectifier circuit  100  is described in detail below. 
         [0026]    When the first AC voltage is in a positive period, during the first half period of the control signals, the first energy sub-unit  23  is charged by the first AC voltage. At the same time, the first energy storing circuit  50  and the second energy storing circuit  60  discharge to the load  200  via the first output terminal  70 . During the second half period of the control signals, the first energy sub-unit  23  discharges energy to the second energy storing circuit  60 . At the same time, the first energy storing circuit  50  and the second energy storing circuit  60  discharge to the load  200  via the first output terminal  70 . 
         [0027]    When the first AC voltage is in a negative period, during the first half period of the control signals, the first energy sub-unit  23  is charged by the first AC voltage. At the same time, the first energy storing circuit  50  and the second energy storing circuit  60  discharge to the load  200  via the second output terminal  80 . During the second half period of the control signals, the first energy sub-unit  23  discharges energy to the first energy storing circuit  50 . At the same time, the first energy storing circuit  50  and the second energy storing circuit  60  discharge to the load  200  via the second output terminal  80 . In the positive period and the negative period of the first AC voltage, when the first energy sub-unit  23  discharges to the first energy circuit  50  and the second energy storing circuit  60 , a first DC voltage is generated. Thus, the first AC voltage is converted into a first DC voltage. The second AC voltage is converted into a second DC voltage by the second rectifier unit  30 , and the third AC voltage is converted into a third DC voltage by the third rectifier unit  70  similar to the first AC voltage being converted into the first DC voltage by the first rectifier unit  20 . 
         [0028]      FIG. 4  is a waveform diagram of the first AC voltage, the second AC voltage, and the third voltage generated by the three-phase AC power supply of  FIG. 1 . A waveform “a” refers to a waveform of the first AC voltage, a waveform “b” refers to a waveform of the second AC voltage, and a waveform “c” refers to a waveform of the third AC voltage. Periods of the waveform a, the waveform b, and the waveform c are divided equally into three time periods: time period “T 1 ,” time period “T 2 ,” and time period “T 3 .” In each of the three time periods, two waveforms have a positive voltage while the third waveform has a negative voltage, or two waveforms have a negative voltage while the third waveform has a positive voltage. For example, at the first time period “T 1 ,” the first AC voltage and the third AC voltage are positive, and the second AC voltage is negative. At a point “A,” the first energy storing circuit  50  is charged by the first energy storing sub-unit  23  of the second rectifier unit  30 , and the second energy storing circuit  60  is charged by the first energy storing sub-units  23  of the first rectifier unit  20  and the third rectifier unit  40 . At a point “B,” the first energy storing circuit  50  is charged by the first energy storing sub-unit  23  of the second rectifier unit  30 , and the first energy storing sub-unit  23  of the third rectifier unit  40 , and the second energy storing circuit  60  is charged by the first energy storing sub-unit  23  of the first rectifier circuit  20 . Thus, energy storage in the first energy storing circuit  50  and the second energy storing circuit  60  are approximately the same. Therefore, the voltage output by the first energy storing circuit  50  and the second storing circuit  60  to the load  200  is steady. 
         [0029]    Although certain embodiments of the present disclosure have been specifically described, the present disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the present disclosure without departing from the scope and spirit of the present disclosure.