This application claims priority of Chinese Application No. 201510362114.5, filed on Jun. 26, 2015.
This disclosure relates to electrical power conversion, and more particularly to a resonant converter.
Conventional resonant converters generally perform electrical power conversion using a half bridge scheme (i.e., requiring two switches) or a full bridge scheme (i.e., requiring four switches). A conventional half bridge resonant converter is advantageously relatively low in cost, but disadvantageously has relatively low conversion efficiency. A conventional full bridge resonant converter advantageously has relatively high conversion efficiency, but is disadvantageously relatively high in cost.
Therefore, an object of this disclosure is to provide a resonant converter that is moderate in cost and that has moderate conversion efficiency.
According to this disclosure, a resonant converter includes a transformer, a first switch, a resonant inductor, a resonant capacitor, a second switch and a third switch. The transformer includes a first primary winding, a second primary winding and a secondary winding. Each of the first and second primary windings has a first end terminal and a second end terminal. The first switch is coupled to the first end terminal of the first primary winding. The resonant inductor and the resonant capacitor are connected in series between the second end terminal of the first primary winding and the first end terminal of the second primary winding. The second switch is coupled between the first end terminals of the first and second primary windings. The third switch is coupled between the second end terminals of the first and second primary windings.
Other features and advantages of this disclosure will become apparent in the following detailed description of the embodiment with reference to the accompanying drawings, of which:
Referring to
The transformer 1 includes a first primary winding 11, a second primary winding 12 and a secondary winding 13. Each of the first and second primary windings 11, 12 and the secondary winding 13 has a first end terminal and a second end terminal. The secondary winding 13 further has an intermediate terminal. In this embodiment, the first and second primary windings 11, 12 have the same number of turns, the first end terminals of the first and second primary windings 11, 12 have the same voltage polarity, and the secondary winding 13 is a center tapped winding.
The first switch 2 is coupled to the first end terminal of the first primary winding 11. In this embodiment, the first switch 2 is an N-type metal oxide semiconductor field effect transistor, and has a drain terminal, a source terminal that is coupled to the first end terminal of the first primary winding 11, and a gate terminal that receives a first control signal (Vgs1).
The resonant inductor 3 and the resonant capacitor 4 are connected in series between the second end terminal of the first primary winding 11 and the first end terminal of the second primary winding 12. In this embodiment, the resonant inductor 3 has one end connected to the second end terminal of the first primary winding 11 and another end connected to the resonant capacitor 4, and the resonant capacitor 4 is connected between said another end of the resonant inductor 3 and the first end terminal of the second primary winding 12.
The second switch 5 is coupled between the first end terminals of the first and second primary windings 11, 12. In this embodiment, the second switch 5 is an N-type metal oxide semiconductor field effect transistor, and has a drain terminal that is coupled to the first end terminal of the first primary winding 11, a source terminal that is coupled to the first end terminal of the second primary winding 12, and a gate terminal that receives a second control signal (Vgs2).
The third switch 6 is coupled between the second end terminals of the first and second primary windings 11, 12. In this embodiment, the third switch 6 is an N-type metal oxide semiconductor field effect transistor, and has a drain terminal that is coupled to the second end terminal of the first primary winding 11, a source terminal that is coupled to the second end terminal of the second primary winding 12, and a gate terminal that receives a third control signal (Vgs3).
The DC input voltage (Vin) is received at the drain terminal of the first switch 2 and the second end terminal of the second primary winding 12. As shown in
The rectifying-and-filtering circuit 7 is coupled to the secondary winding 13 for receiving the AC voltage therefrom, and for rectifying and filtering the AC voltage to generate the DC output voltage (Vo). In this embodiment, the rectifying-and-filtering circuit 7 includes a first diode 71 and a second diode 72 that are used for rectification, and an output capacitor 73 that is used for filtering. The first diode 71 has an anode that is coupled to the first end terminal of the secondary winding 13, and a cathode. The second diode 72 has an anode that is coupled to the second end terminal of the secondary winding 13, and a cathode that is coupled to the cathode of the first diode 71. The output capacitor 73 is coupled between the cathode of the first diode 71 and the intermediate terminal of the secondary winding 13, and a voltage thereacross serves as the DC output voltage (Vo).
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In view of the above, the resonant converter of this embodiment has the following advantages:
1. Since three switches (i.e., the first to third switches 2, 5, 6) are required, the resonant converter of this embodiment has moderate conversion efficiency (i.e., higher than the conversion efficiency of the conventional half bridge resonant converter, but lower than the conversion efficiency of the conventional full bridge resonant converter), and moderate costs (i.e., greater than the costs of the conventional half bridge resonant converter, but lower than the costs of the conventional full bridge resonant converter).
2. Since a maximum value of each of the voltages respectively across the second and third switches 5, 6 is about (⅔)×Vin, each of the second and third switches 5, 6 endures relative low voltage stress as compared to the switches of the conventional half bridge and full bridge resonant converters.
3. The voltage across each of the first and second primary windings 11, 12 of the transformer 1 has an amplitude of about (⅓)×Vin. Therefore, as compared to a transformer of the conventional half bridge resonant converter, a turn ratio of the first primary winding 11 to the secondary winding 13 and a turn ratio of the second primary winding 12 to the secondary winding 13 are relatively small, and each of the first and second primary windings 11, 12 endures relatively low current stress. In addition, as compared to the switches of the conventional half bridge resonant converter, each of the second and third switches 5, 6 endures relatively low current stress, resulting in relatively low conduction loss.
4. Zero voltage switching can be achieved.
While this disclosure has been described in connection with what is considered the exemplary embodiment, it is understood that this disclosure is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
Number | Date | Country | Kind |
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2015 1 0362114 | Jun 2015 | CN | national |
Number | Name | Date | Kind |
---|---|---|---|
3711747 | Sahara | Jan 1973 | A |
3745440 | Lord | Jul 1973 | A |
4130862 | Holt | Dec 1978 | A |
4255782 | Joyce | Mar 1981 | A |
5946206 | Shimizu | Aug 1999 | A |
7920391 | Vinciarelli | Apr 2011 | B1 |
8693222 | Yonezawa | Apr 2014 | B2 |
20020001203 | Jitaru | Jan 2002 | A1 |
20050047175 | Kawasaki | Mar 2005 | A1 |
20050226008 | Harada | Oct 2005 | A1 |
20060139970 | Cheng | Jun 2006 | A1 |
20060250822 | Nakagawa | Nov 2006 | A1 |
20120025720 | Chen | Feb 2012 | A1 |
20120320638 | Boysen | Dec 2012 | A1 |
20140098572 | Scarlatescu | Apr 2014 | A1 |
20140232282 | Rooijackers | Aug 2014 | A1 |
20140268904 | Reddy | Sep 2014 | A1 |
20150049517 | Yan | Feb 2015 | A1 |
20150109831 | Ohashi | Apr 2015 | A1 |
20150229216 | Kyono | Aug 2015 | A1 |
20160072388 | Dubus | Mar 2016 | A1 |
Number | Date | Country | |
---|---|---|---|
20160380548 A1 | Dec 2016 | US |