RU1812603C - Half-bridge resonant converter of direct voltage - Google Patents

Description

The invention relates to electrical engineering and can be used to power electronic equipment.

The purpose of the invention is to increase efficiency.

To achieve the goal in a half-bridge resonant constant-voltage converter, the smoothing inductor is double-wound, with its windings connected between free power switches and input terminals, and the rectifier output connected to the output terminals and shunted by an additional capacitor.

Figure 1 shows a diagram of the proposed Converter; in Fig.2 - time diagrams of his work.

The half-bridge resonant DC / DC converter contains de-connected power switches 1, 2 and a capacitive voltage divider consisting of capacitors 5, 6, a resonant capacitor 7, a resonant inductor 8, a transformer 9, a rectifier connected to the input terminals 3, 4 10, a smoothing inductor 11, an additional capacitor 12 connected to the output terminals 13, 14. The power switches 1, 2 are controlled by the control unit 15.

In the diagrams of FIG; 2 is indicated:

Uyi, the voltage at the outputs of the control unit 15;

Uc is the voltage at the resonant capacitor 7; (

JK is the current in the circuit of the resonant throttle 8;

Jl.Ja currents in power switch circuits 1, 2;

Ut, U2 - voltage at power switches 1,2.

A half-bridge resonant DC / DC converter operates as follows.

At a point in time. under the influence of signals Uyi, Uy2 from the control unit 15, the power switch 1 is locked and the power switch 2 is open. The resonant capacitor 7 begins to charge with a current of a smoothing jumper 11 along the circuit; input terminal 3, capacitor 5, resonant capacitor 7, power switch 2, lower winding of smoothing throttle 11, input terminal 4, When the voltage at resonant capacitor 7 reaches a value equal to the value converted to the primary winding of transformer 9 of the output voltage On the other hand, the current of the resonant choke 8 begins to increase. Under the action of this current, energy is transferred to the additional capacitor 12 and to the load connected to the output terminals 13, 14. At time t2, the power switch 1 is unlocked by the signal Uyi from bl Single control 15. The current smoothing choke 11 is closed along the chain; input terminal 3, upper winding of smoothing throttle 11, power switch 1, power switch 2, lower winding of smoothing throttle 11, input terminal 4. Its amplitude decreases in this case

two times due to a twofold increase in the number of turns with a constant magnetic flux in the core of the smoothing jumper 11. The current of the resonant jumper 8 recharges the resonant capacitor 7.

At time t3, the energy stored in the resonant inductor 8, as well as the current through it and the voltage at the resonant capacitor 7, are reduced to zero. At time T4 SIGNAL Uy2 POWER KEY

2 is locked, the described processes are repeated when the keys are switched in the opposite order, the voltage polarity on the resonant capacitor 7 and the flow direction

current through the resonant inductor 8,

In accordance with the diagram of Fig. 2, switching of the power switches 1,2 occurs at zero voltages on them. At the same time, dynamic losses in power switches 1, 2

minimized, since the value of the through current through them is limited by a smoothing inductor 11, the efficiency of the described converter is higher than in the prototype device also by reducing losses

power in the resonant circuit due to the exclusion of an additional capacitor from it.

Formulas of the invention

A half-bridge resonant DC / DC converter, comprising two series-connected power switches and a capacitive voltage divider connected to the input terminals,

the midpoint of which is connected to the combined terminals of the power switches through the resonant capacitor and through the resonant inductor and the primary winding of the transformer connected in series,

the secondary winding of which is connected to the input of the rectifier, a smoothing inductor and an additional capacitor, characterized in that, in order to increase the efficiency, the smoothing inductor is made

double winding, with its windings connected between the free terminals of the power switches and the extreme terminals of the capacitive voltage divider, and the rectifier output connected to the output terminals and shunted by an additional capacitor.

and.,

L i

FIG. 2