Non-isolated LLC resonant converter
View Patent ↗The present disclosure discloses a non-isolated LLC resonant converter, comprising a first switch network module, a second switch network module, a resonance network module, a transformer module, a rectification network module and an output module, wherein via signals under drive control input on the first switch network module, the second switch network module and the rectification network module, it is controlled to realize zero-voltage switching (ZVS) and zero-current switching (ZCS) of a switch in a resonant state, thereby reducing switching loss of a switch unit, improving electric energy conversion efficiency and reducing production cost and power density, wherein simultaneously a quantity of turns of a primary winding of a transformer is saved, a loss of the primary winding of the transformer is reduced, a manufacturing cost of the power converter is reduced, simultaneously, a space of a transformer winding is saved, and design requirements of smaller volume are realized.
1. A non-isolated LLC resonant converter, characterized by comprising a first switch network module ( 101 ), a second switch network module ( 102 ), a resonance network module ( 103 ), a transformer module ( 104 ), a rectification network module ( 105 ) and an output module, wherein
the first switch network module ( 101 ) and the second switch network module ( 102 ) are connected to a power supply, the resonance network module ( 103 ), the transformer module ( 104 ) and the rectification network module ( 105 ) simultaneously for communicating with each module;
the transformer module ( 104 ), the rectification network module ( 105 ) and the output module are connected;
the first switch network module ( 101 ) comprises a first switch (Q 1 ) and a second switch (Q 2 ); the second switch network module ( 102 ) comprises a third switch (Q 3 ) and a fourth switch (Q 4 );
a first end of the first switch (Q 1 ) is connected to a positive electrode of the power supply, and a second end of the first switch (Q 1 ) is connected to a first end of the second switch (Q 2 ) and one end of the resonance network module ( 103 ) simultaneously;
a second end of the second switch (Q 2 ) is connected to the transformer module ( 104 ) and the rectification network module ( 105 ) simultaneously;
a first end of the third switch (Q 3 ) is connected to the positive electrode of the power supply, and a second end of the third switch (Q 3 ) is connected to the other end of the resonance network module ( 103 ) and a first end of the fourth switch (Q 4 ) simultaneously;
a second end of the fourth switch (Q 4 ) is connected to the transformer module ( 104 ) and the rectification network module ( 105 ) simultaneously;
the resonance network module ( 103 ) comprises an excitation inductance (Lm), a resonance inductance (Lr) and a resonance capacitance (Cr);
one end of the resonance capacitance (Cr) is connected to the first switch network module ( 101 ), the other end of the resonance capacitance (Cr) is connected to one end of the excitation inductance (Lm), the other end of the excitation inductance (Lm) is connected to one end of the resonance inductance (Lr), and the other end of the resonance inductance (Lr) is connected to the second switch network module ( 102 );
the transformer module ( 104 ) comprises a primary winding (Np), a first secondary winding (Ns 1 _ 1 ), a second secondary winding (Ns 2 _ 1 ), a third secondary winding (Ns 2 _ 2 ) and a fourth secondary winding (Ns 1 _ 2 );
the primary winding (Np) is connected in parallel to the excitation inductance (Lm), a same-name end of the first secondary winding (Ns 1 _ 1 ) is connected to the first switch network module ( 101 ) and the rectification network module ( 105 ) simultaneously, a different-name end of the first secondary winding (Ns 1 _ 1 ) is connected to a same-name end of the second secondary winding (Ns 2 _ 1 ), a same-name end of the third secondary winding (Ns 2 _ 2 ), a different-name end of the fourth secondary winding (Ns 1 _ 2 ) and the output module simultaneously;
a different-name end of the second secondary winding (Ns 2 _ 1 ) is connected to the second switch network module ( 102 ) and the rectification network module ( 105 ) simultaneously, a different-name end of the third secondary winding (Ns 2 _ 2 ) is connected to the rectification network module ( 105 ), and a same-name end of the fourth secondary winding (Ns 1 _ 2 ) is connected to the rectification network module ( 105 );
the rectification network module ( 105 ) comprises a fifth switch (SR 1 ), a sixth switch (SR 2 ), a seventh switch (SR 3 ) and an eighth switch (SR 4 );
a first end of the fifth switch (SR 1 ) is connected to the same-name end of the first secondary winding (Ns 1 _ 1 ), and a second end of the fifth switch (SR 1 ) is connected to a negative electrode of the power supply;
a first end of the sixth switch (SR 2 ) is connected to the different-name end of the third secondary winding (Ns 2 _ 2 ), and a second end of the sixth switch (SR 2 ) is connected to the negative electrode of the power supply;
a first end of the seventh switch (SR 3 ) is connected to the same-name end of the fourth secondary winding (Ns 1 _ 2 ), and a second end of the seventh switch (SR 3 ) is connected to the negative electrode of the power supply;
a first end of the eighth switch (SR 4 ) is connected to the different-name end of the second secondary winding (Ns 2 _ 1 ), and a second end of the eighth switch (SR 8 ) is connected to the negative electrode of the power supply;
the output module comprises an output capacitance (Co) and a load resistance (Ro);
one end of the output capacitance (Co) is connected to the different-name end of the first secondary winding (Ns 1 _ 1 ), and the other end of the output capacitance (Co) is connected to the negative electrode of the power supply; and
one end of the load resistance (Ro) is connected to the different-name end of the first secondary winding (Ns 1 _ 1 ), and the other end of the load resistance (Ro) is connected to the negative electrode of the power supply.
2. The non-isolated LLC resonant converter according to claim 1 , characterized by further comprising an input capacitance (Cin), one end of the input capacitance (Cin) being connected to the positive electrode of the power supply and the other end being connected to the negative electrode of the power supply.
3. The non-isolated LLC resonant converter according to claim 1 , characterized in that the first switch (Q 1 ), the second switch (Q 2 ), the third switch (Q 3 ) and the fourth switch (Q 4 ) are controllable switching devices; and
the first switch (Q 1 ), the second switch (Q 2 ), the third switch (Q 3 ) and the fourth switch (Q 4 ) are a metal-oxide-semiconductor field effect transistor, an insulated gate bipolar transistor, a gallium nitride transistor, a silicon carbide MOS transistor or a first combined switch unit, and the first combined switch unit is a combined switch of a triode and a diode.
4. The non-isolated LLC resonant converter according to claim 1 , characterized in that the fifth switch (SR 1 ), the sixth switch (SR 2 ), the seventh switch (SR 3 ) and the eighth switch (SR 8 ) are controllable switching devices or uncontrollable switching devices.
5. The non-isolated LLC resonant converter according to claim 1 , characterized in that the fifth switch (SR 1 ), the sixth switch (SR 2 ), the seventh switch (SR 3 ) and the eighth switch (SR 8 ) are a metal-oxide-semiconductor field effect transistor, an insulated gate bipolar transistor, a gallium nitride transistor, a silicon carbide MOS transistor, a diode, a first combined switch unit or a second combined switch unit; and
the first combined switch unit is a combined switch of a triode and a diode, and the second combined switch unit is a combined switch of a diode and any one of a metal-oxide-semiconductor field effect transistor, an insulated gate bipolar transistor, a gallium nitride transistor and a silicon carbide MOS transistor.
6. The non-isolated LLC resonant converter according to claim 1 , characterized in that a resonance frequency of the resonance network module ( 103 ) is:
fr
=
1
2
π
LrCr
,
wherein Lr represents an inductance value of the resonance inductance (Lr) and Cr represents a capacitance value of the resonance capacitance (Cr).
7. The non-isolated LLC resonant converter according to claim 6 , characterized in that a setting range of a switch frequency of switches in the first switch network module ( 101 ), the second switch network module ( 102 ) and the rectification network module ( 105 ) are: 0.5*fr≤fs≤2*fr.
8. The non-isolated LLC resonant converter according to claim 7 , characterized in that the switch frequency of the switches in the first switch network module ( 101 ), the second switch network module ( 102 ) and the rectification network module ( 105 ) are set to: fs=fr.
9. The non-isolated LLC resonant converter according to claim 1 , characterized in that the first secondary winding (Ns 1 _ 1 ), the second secondary winding (Ns 2 _ 1 ), the third secondary winding (Ns 2 _ 2 ) and the fourth secondary winding (Ns 1 _ 2 ) have the same quantity of winding turns.
10. The non-isolated LLC resonant converter according to claim 1 , characterized in that when the non-isolated LLC resonant converter is operated in a resonant state, during one resonance cycle, a drive control signal PWM 1 is input on the first switch (Q 1 ), the fourth switch (Q 4 ), the fifth switch (SR 1 ), and the seventh switch (SR 3 ), and a drive control signal PWM 2 is input on the second switch (Q 2 ), the third switch (Q 3 ), the sixth switch (SR 2 ), and the eighth switch (SR 4 ), the drive control signal PWM 1 and the drive control signal PWM 2 are complementary and both have a duty ratio of 50%, and a dead time is set between the drive control signal PWM 1 and the drive control signal PWM 2 .