The present disclosure relates to power conversion, in particular to a flyback AC-DC conversion device and the conversion method thereof.
The most obvious different between a flyback electricity energy transmission system and a common contact-type energy transmission is that the flyback electricity energy transmission system does not need to directly transmit the electricity energy via the power lines, but transmit the electricity energy from the primary side to the secondary side via the electromagnetic coupling of the flyback transformer; however, due to the poor coupling of the flyback transformer, the power conversion efficiency will be decreased. Thus, the conventional flyback electricity energy transmission system usually uses the resonant-type impedance matching method to increase the power conversion efficiency; however, the circuit realized by the resonant-type impedance matching method tends to be influenced by the coupling coefficients of the flyback transformer, so cannot reach the anticipated effect, which will reduce the power conversion efficiency.
In addition, as the output voltage of the electricity energy transmission system should be higher than the voltage of the load so as to overcome the potential of the output end to transmit the electricity energy to the load; thus, the flyback electricity energy transmission system always needs a transformer with high turn ratio to increase the voltage to the desired voltage; in this way, the copper loss of the flyback transformer will be increased with the increase of turn number of the coil, which will reduce the power conversion efficiency.
Accordingly, the usage and structure of the aforementioned currently available flyback electricity energy transmission system still have a lot of inconveniences and shortcomings needed to be further improved. For the purpose of solving the existing 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, which currently become the most serious problems that the circuit designers need to solve in a short time.
The major object of the present invention is to provide a flyback AC-DC conversion device, which can provide negative potential to compensate for the barrier of the load voltage so as to further reduce the coil turn ratio of the transformer and reduce the copper loss to increase the power conversion efficiency; therefore, the electricity energy of the primary side of the transformer can be more smoothly and efficiently transmitted to the load in order to further better the power conversion efficiency.
The object of the present invention can be realized by adopting the following technical schemes. The present invention provides a flyback AC-DC conversion device for converting the electricity energy of an AC power source and outputting the electricity energy to a load; the flyback AC-DC conversion device includes: a rectifier circuit, which is connected to the AC power source, and used for receiving the electricity energy of the AC power source, converting the electricity energy into the DC electricity energy and outputting the DC electricity energy; an electronic switch, which is electrically connected to the rectifier circuit; a flyback transformer, which has a primary side and a secondary side, and two terminals of the primary side are electrically connected to the rectifier circuit and the electronic switch respectively, and the secondary side has a first terminal and a second terminal; and the automatic charge pumping circuit, wherein one side thereof is electrically connected to the flyback transformer, and the other side thereof is electrically connected to the load; the automatic charge pumping circuit includes: a first diode, wherein the anode thereof is connected to the second terminal of the secondary side, and the cathode thereof is connected to the first terminal of the secondary side; a first capacitor, wherein one end thereof is connected to the cathode of the first diode; an inductor, wherein one end thereof is connected to the other end of the first capacitor, and the other end thereof is electrically connected to the cathode of the first diode; a second capacitor connected to the load in parallel, wherein one end thereof is connected to the first capacitor and the inductor, and the other end thereof is connected to the anode of the first diode and the second terminal of the secondary side.
The object of the present invention can be further realized by adopting the following technical measures.
Preferably, regarding the aforementioned flyback AC-DC conversion device, the automatic charge pumping circuit further includes a second diode; one end thereof is connected to the first terminal of the secondary side of the flyback transformer, and the other end thereof is connected to the cathode of the first diode, whereby the first diode is electrically connected to the first terminal of the secondary side of the flyback transformer via the second diode.
Preferably, regarding the aforementioned flyback AC-DC conversion device, the anode of the second diode is connected to the first terminal of the secondary side of the flyback transformer, and the cathode thereof is connected to the cathode of the first diode.
Preferably, regarding the aforementioned flyback AC-DC conversion device, the automatic charge pumping circuit further includes a third diode; one end thereof is connected to the cathode of the first diode, and the other end thereof is connected to the inductor, whereby the inductor is electrically connected to the cathode of the first diode via the third diode.
Preferably, regarding the aforementioned flyback AC-DC conversion device, the anode of the third diode is connected to the anode of the first diode, and the cathode thereof is connected to the inductor.
The object of the present invention can be realized by adopting the following technical schemes. The present invention provides a power conversion method of the aforementioned flyback AC-DC conversion device, including the following steps: A. turning on the electronic switch to charge the primary side of the flyback transformer by the DC electricity energy outputted by the rectifier circuit, and powering the load by the inductor, the first capacitor and the second capacitor; B. turning off the electronic switch to make the rectifier circuit stop outputting the DC electricity energy and make the secondary side of the flyback transformer charge the inductor, the first capacitor and the second capacitor, and make the second capacitor keep powering the load; C. the flyback transformer stopping charging to make the inductor charge the first capacitor, and reverse the polarity of the voltage across the first capacitor, and powering the load by the second capacitor; D. turning on the first diode to reverse the polarity of the voltage across the first capacitor and the polarity of the voltage across the inductor to charge the second capacitor, and making the second capacitor keep powering the load.
The object of the present invention can be realized by adopting the following technical measures.
Preferably, the aforementioned power conversion method further includes a step after the step D, and the step is to repeat executing the step A to the step D.
Preferably, regarding the aforementioned power conversion method, during the step B, the secondary side of the flyback transformer charges the second capacitor via the resonant circuit formed by the first capacitor and the inductor.
Preferably, regarding the aforementioned power conversion method, during the step C, after the first capacitor and the inductor form the resonant circuit, the inductor charges the first capacitor to reverse the polarity of the voltage across the first capacitor; when the voltage across the inductor is higher than the voltage across the second capacitor, the first diode is turned on, and the method proceeds to the step D.
By means of the above technical schemes, the flyback AC-DC conversion device and the conversion method thereof in accordance with the present invention have at least the following advantages and beneficial effects: via the design of the present invention, the device can provide negative potential to compensate for the barrier of the load voltage so as to further reduce the coil turn ratio of the flyback transformer and reduce the copper loss to increase the power conversion efficiency; therefore, the electricity energy of the primary side of the transformer can be more smoothly and efficiently transmitted to the load in order to further better the power conversion efficiency.
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.
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.
Please refer to
The rectifier circuit R is connected to the AC power source 100; in the embodiment, the rectifier circuit R is a bridge rectifier, and used for receiving the electricity energy of the AC power source, converting the electricity energy into the DC electricity energy and outputting the DC electricity energy. Of course, in another embodiment, the rectifier circuit R can be a center-tapped type rectifier, a vacuum-tube type rectifier and the like, which can also achieve the same object.
The electronic switch SW is electrically connected to the rectifier circuit R to be controlled to turn on or turn off the DC electricity energy outputted by the rectifier circuit R.
The flyback transformer 10 has a primary side 11 and a secondary side 12. Two terminals of the primary side 11 is electrically connected to the rectifier circuit R and the electronic switch SW respectively, and the secondary side 12 has a first terminal 121 and a second terminal 122.
One side of the automatic charge pumping circuit 20 is electrically connected to the flyback transformer 10, and the other side thereof is electrically connected to the load 200. The automatic charge pumping circuit 20 includes 3 diodes (the first diode D1, the second diode D2 and the third diode D3), 2 capacitors (the first capacitor C1 and the second capacitor C2) and an inductor L. The connection relations of the above components are as follows:
The anode of the first diode D1 is connected to the second terminal 122 of the secondary side 12, and the cathode thereof is connected to the first terminal 121 of the secondary side 12.
One end of the first capacitor C is connected to the cathode of the first diode D1 and the cathode of the second diode D2.
One end of the inductor L is connected to the other end of the first capacitor C1, and the other end thereof is connected to the cathode of the third diode D3 so as to be electrically connected to the cathode of the first diode D1 via the third diode D3.
The second capacitor C2 is connected to the load 200 in parallel and is a non-electrolyte capacitor; one end thereof is connected to the first capacitor C1 and the inductor L, and the other end thereof is connected to the anode of the first diode D1 and the second terminal 122 of the secondary side 12.
In the embodiment, the specifications of the capacitors C1˜C2, the inductor L, the input voltage, the switching frequency of the electronic switch SW and the load 200 are as shown in the following Table 1:
The object of bettering the power conversion efficiency can be achieved by integrating the above structure design and specification with the following power conversion method; the method includes the following steps:
A. please refer to
B. please refer to
C. please refer to
D. please refer to
After each of the step A˜step D is executed for one time, it means one operation cycle is finished. Thus, when the flyback AC-DC conversion device keeps being in operation, the step A˜step D will be repeatedly executed after the step D until the flyback AC-DC conversion device is turned off.
By means of the above design of the flyback AC-DC conversion device, in each operation cycle, the voltage Vc1 across the first capacitor C1 can automatically provide negative potential, as shown in
Moreover, the design of the second diode D2 and the third diode D3 can further effectively prevent the backflow of the circuit from influencing the operations of the flyback transformer 10 and the automatic charge pumping circuit 20 respectively, which can make the whole circuit more stable so as to better the power conversion and the ripple voltage suppression effect of the flyback AC-DC 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 second diode D2 and the third diode D3.
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.
Number | Date | Country | Kind |
---|---|---|---|
201310616349.3 | Nov 2013 | CN | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/CN2014/000914 | 10/15/2014 | WO | 00 |