A kind of half-bridge LC resonance translation circuit based on PWM controls
Technical field
The utility model belongs to Switching Power Supply applied technical field, and in particular to a kind of half-bridge LC based on PWM controls is humorous
Shake translation circuit.
Background technology
When the voltage change of input translator, the stabilization of output voltage is realized, fixed in the switching frequency of converter
When, the pulsewidth for being input to half-bridge power pipe also can be with changing, and power tube realizes the item of zero current turning-on zero-current switching
Part is the LC harmonic periods that pulse width (turn-on time) is equal to loop of power circuit;So power tube pulse width variations, the parameter of LC
It must be there are one changing.
Utility model content
In view of this, the main purpose of the utility model is to provide a kind of half-bridge LC resonant transformations based on PWM controls
Circuit.
In order to achieve the above objectives, the technical solution of the utility model is realized in:
The utility model embodiment provides a kind of half-bridge LC resonance translation circuit controlled based on PWM, which includes:
Input power BT1, for providing electric energy for entire circuit;
First main power tube Q1, the second main power tube Q2, for forming half-bridge circuit;
Resonant inductance L1 and its primary side winding N1, vice-side winding N2, resonant capacitance C1, for forming LC resonance circuit;
First clamp diode D1, the second clamp diode D2 are used for the original edge voltage spike of the main power transformer of clamper
Less than input supply voltage;
First input filter capacitor C2, the second input filter capacitor C3, for being filtered to input voltage;
Main power transformer T1 and its primary side winding N1 and vice-side winding N2, N3, have been used for transformer action;
First output rectifier diode D3, the second output rectifier diode D4, output filter capacitor C4, for forming rectification
And filter circuit.
In said program, the positive and negative anodes of the input power BT1 are coupled with by the poles D of the first main power tube Q1 and
The poles S of two main power tube Q2;Positive and negative anodes difference after the first input filter capacitor C2, the second input filter capacitor C3 series connection
It is connected to the positive and negative anodes of input power BT1;Primary side N2, the resonant capacitance of the midpoint priority series resonance inductor L1 of the half-bridge circuit
One end of the primary side winding N1 of main power transformer T1 is connected to after C1, one end of the primary side winding N1 also connects the first pincers simultaneously
The cathode of the anode and the second clamp diode D2 of position diode D1, the cathode and D2 anodes of clamp diode D1 connect input respectively
The positive and negative anodes of power supply, the former other end for becoming winding N1 of main power transformer T1 are connected to the cathode of input filter capacitor C2 simultaneously
With the anode of C3;The vice-side winding N2 and N3 of the main power transformer T1 is coupled with the first output rectifier diode D3,
The anode of two output rectifier diode D4, described first exports the cathode of rectifier diode D3, the second output rectifier diode D4
The vice-side winding N2 of series resonance inductor L1, is connected to the anode of output filter capacitor C4 later after being connected together.
In said program, the primary side winding N1 of the resonant inductance L1 is connected on resonant tank, and vice-side winding N2 is connected on
The commutating circuit on transformer T1 pairs side.When loading constant, with the increase of input voltage, the duty ratio of power tube can be smaller,
The peak point current on primary side pair side can all increase.Since the peak point current on secondary side increases, the coupling of N1 and N2, so the inductance meeting of N1
Reduce, this results in primary side resonant frequency to rise, and harmonic period reduces.When meet transformer primary side pair side turn ratio be equal to it is humorous
It shakes the turn ratio on inductance L1 primary side pairs side, variation of the variation equal to harmonic period of power tube pulsewidth can be met.
In said program, the turn ratio of the primary side vice-side winding of the transformer T1 is equal to the primary side pair of resonant inductance L1
The turn ratio of side winding.
Compared with prior art, the beneficial effects of the utility model:
The principle that inductance double winding is mutually coupled electromagnetic induction is dexterously utilized in the utility model, realizes resonant inductance
It follows input voltage and load variation and changes, follow PWM to open the period to realize harmonic period, become in input voltage
All whole process realizes power tube and the ZCS of rectifying tube is turned on and off when changing and loading variation, to greatly improve power supply
Efficiency and EMC performances;Resonant inductance L follows the pulse width variations of power tube and changes in the utility model.
Description of the drawings
Fig. 1 provides a kind of circuit diagram of the half-bridge LC resonance translation circuit controlled based on PWM for the utility model embodiment;
Fig. 2 provides the first master in a kind of half-bridge LC resonance translation circuit controlled based on PWM for the utility model embodiment
The current-voltage waveform figure of power tube Q1 and the second main power tube Q2.
Specific implementation mode
In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing and implementation
Example, the present invention will be further described in detail.It should be appreciated that specific embodiment described herein is only used to explain
The utility model is not used to limit the utility model.
The utility model follows the pulse width variations of power tube using resonant inductance L and changes.
The utility model embodiment provides a kind of half-bridge LC resonance translation circuit controlled based on PWM, as shown in Figure 1, should
Circuit includes:
Input power BT1, for providing electric energy for entire circuit;
First main power tube Q1, the second main power tube Q2, for forming half-bridge circuit;
Resonant inductance L1 and its primary side winding N1, vice-side winding N2, resonant capacitance C1, for forming LC resonance circuit;
First clamp diode D1, the second clamp diode D2 are used for the original edge voltage spike of the main power transformer of clamper
Less than input supply voltage;
First input filter capacitor C2, the second input filter capacitor C3, for being filtered to input voltage;
Main power transformer T1 and its primary side winding N1 and vice-side winding N2, N3, have been used for transformer action;
First output rectifier diode D3, the second output rectifier diode D4, output filter capacitor C4, for forming rectification
And filter circuit.
The positive and negative anodes of the input power BT1 are coupled with the poles D and the second main power tube Q2 by the first main power tube Q1
The poles S;Positive and negative anodes after the first input filter capacitor C2, the second input filter capacitor C3 series connection are coupled with input electricity
The positive and negative anodes of source BT1;It is connected to after primary side N2, the resonant capacitance C1 of the midpoint priority series resonance inductor L1 of the half-bridge circuit
One end of one end of the primary side winding N1 of main power transformer T1, the primary side winding N1 also meets the first clamp diode D1 simultaneously
Anode and the second clamp diode D2 cathode, the cathode and D2 anodes of clamp diode D1 connect the positive and negative of input power respectively
The former other end for becoming winding N1 of pole, main power transformer T1 is connected to the cathode of input filter capacitor C2 and the anode of C3 simultaneously;
The vice-side winding N2 and N3 of the main power transformer T1 is coupled with the first output rectifier diode D3, the second output rectification two
The anode of pole pipe D4, the first output rectifier diode D3, the second cathode for exporting rectifier diode D4 are gone here and there after being connected together
The vice-side winding N2 for joining resonant inductance L1, is connected to the anode of output filter capacitor C4 later.
The primary side winding N1 of the resonant inductance L1 is connected on resonant tank, and vice-side winding N2 is connected on transformer T1 pairs side
Commutating circuit.When loading constant, with the increase of input voltage, the duty ratio of power tube can be smaller, the peak on primary side pair side
Value electric current can all increase.Since the peak point current on secondary side increases, the coupling of N1 and N2, so the inductance of N1 can reduce, this just leads
Primary side resonant frequency is caused to rise, harmonic period reduces.When the turn ratio for meeting transformer primary side pair side is equal to resonant inductance L1 originals
Turn ratio in pair can meet variation of the variation equal to harmonic period of power tube pulsewidth.
The number of turns of primary side vice-side winding of the turn ratio of the primary side vice-side winding of the transformer T1 equal to resonant inductance L1
Than.
Main power tube can make MOSFET can also be IGBT and triode etc..Rectifier diode can be MOSFET,
IGBT and triode etc..
The LC resonance period follows PWM to open the period.
Primary side circuit in the utility model is not limited to half-bridge structure, is further adapted to full bridge structure, secondary side commutating circuit
It is not limited to full-wave rectification and applies also for full-bridge rectification.The secondary side of resonant inductance is not limited to be connected on before or after rectifying tube,
Still directly it is connected on main transformer pair side.
As shown in Fig. 2, Q1UDS is the DS pole tension waveforms of the first main power tube Q1;Q2UDS is the second main power tube Q2's
DS electrode current waveforms;Q1IDS is the DS pole tension waveforms of the first main power tube Q1;Q2IDS is the poles DS of the second main power tube Q2
Current waveform.
The above, the only preferred embodiment of the utility model, are not intended to limit the protection of the utility model
Range.