CN105939108A - A Switched Inductance Quasi-Switch Step-Up DC-DC Converter - Google Patents

Abstract

The invention provides a switch inductance type quasi-switch boosting DC-DC converter circuit which comprises a voltage source, a switch inductance unit, a two-end quasi-switch boosting unit, a second MOS (metal oxide semiconductor) tube, a second capacitor, a second diode, an output filter capacitor and a load, wherein the switch inductance unit is composed of a first inductor, a second inductor, a fourth diode, a fifth diode and a sixth diode, the two-end quasi-switch boosting unit is composed of a first capacitor, a first diode, a first MOS tube, a third diode and a switch inductance unit, and the two-end quasi-switch boosting unit is composed of a second capacitor, a first diode. The whole circuit is simple in structure, and the respective single-stage boosting characteristics of the quasi-switch boosting unit, the switch capacitor unit and the switch inductor unit are combined, so that the expansion of output voltage gain is realized.

Description

A kind of switched inductors type quasi-boost switching DC-DC converter

Technical field

The present invention relates to Power Electronic Circuit technical field, be specifically related to a kind of switched inductors type quasi-boost switching DC-DC converter circuit.

Background technology

In fuel cell power generation, photovoltaic generation, the DC voltage provided due to single solaode or single fuel cell is relatively low, the need for electricity of existing electrical equipment cannot be met, grid-connected demand can not be met, generally require the voltage reaching required that is together in series by multiple batteries.On the one hand this method greatly reduces the reliability of whole system, the most also needs to solve series average-voltage problem.For this reason, it may be necessary to can be high-tension high-gain DC-DC converter low voltage transition.The switching boost converter SBI proposed in recent years is little due to the excursion of its output voltage, and in the occasion of low-voltage high input voltage output, such as distributed energy grid-connected system and fuel cell system, tradition SBI changer becomes no longer to be suitable for.In order to expand the scope of application of tradition SBI changer, it is necessary to improved by topology and expand its output voltage gain.

Summary of the invention

It is an object of the invention to overcome above-mentioned the deficiencies in the prior art, it is provided that a kind of switched inductors type quasi-boost switching DC-DC converter circuit, concrete technical scheme is as follows.

A kind of switched inductors type quasi-boost switching DC-DC converter circuit, including voltage source, by the first inductance, the switched inductors unit that second inductance, the 4th diode, the 5th diode and the 6th diode are constituted, by the first electric capacity, the first diode, the first metal-oxide-semiconductor, the two ends quasi-boost switching unit that 3rd diode and switched inductors unit are constituted, second metal-oxide-semiconductor, the second electric capacity, the second diode, output diode, output filter capacitor and load are constituted.

In above-mentioned a kind of switched inductors type quasi-boost switching DC-DC converter circuit, the positive pole of described voltage source is connected with the negative pole of the first electric capacity and the anode of the 3rd diode respectively；The positive pole of described first electric capacity anode with negative electrode, the drain electrode of the first metal-oxide-semiconductor and the output diode of the first diode respectively is connected；The source electrode of described first metal-oxide-semiconductor anode with negative electrode, one end of the first inductance and the 4th diode of the 3rd diode respectively is connected；The negative electrode of described 4th diode is connected with the negative electrode of the 5th diode and one end of the second inductance respectively；The other end of described first inductance is connected with the anode of the 5th diode and the anode of the 6th diode respectively；The anode of described first diode negative electrode with the other end, the drain electrode of the second metal-oxide-semiconductor, the positive pole of the second electric capacity and the 6th diode of the second inductance respectively is connected；The negative pole of described second electric capacity one end with the anode of the second diode, the negative pole of output filter capacitor and load respectively is connected；The negative electrode of described output diode is connected with the positive pole of output filter capacitor and the other end of load respectively；The negative pole of described voltage source is connected with source electrode, the negative electrode of the second diode of the second metal-oxide-semiconductor respectively.

Compared with prior art, circuit of the present invention has the advantage that and technique effect: the whole circuit structure of the present invention is simple, and easy to control, output voltage gain is higher；Circuit of the present invention utilizes the single-stage buck characteristic of quasi-boost switching unit and switched inductors and switching capacity to charge parallel the characteristic of discharged in series, thus increases output voltage, it is achieved that the expansion of quasi-switching boost converter output voltage gain.

Accompanying drawing explanation

Fig. 1 is a kind of switched inductors type quasi-boost switching DC-DC converter circuit in the specific embodiment of the invention.

Fig. 2 a, Fig. 2 b are the equivalent circuit diagram that a kind of switched inductors type quasi-boost switching DC-DC converter circuit shown in Fig. 1 simultaneously turned at its first metal-oxide-semiconductor and the second metal-oxide-semiconductor and simultaneously turn off the period respectively.

Fig. 3 is gain curve and Boost, switching capacity Boost, traditional Z source DC-DC converter and the gain curve comparison diagram of novel quasi-Z source DC-DC converter of circuit of the present invention.

Detailed description of the invention

Technical scheme is explained in detail by above content, is embodied as being further described to the present invention below in conjunction with accompanying drawing.

With reference to Fig. 1, a kind of switched inductors type quasi-boost switching DC-DC converter circuit of the present invention, including voltage source, by the first inductance, the second inductance, the 4th diode, the switched inductors unit that 5th diode and the 6th diode are constituted, by the first electric capacity, the first diode, first metal-oxide-semiconductor, the two ends quasi-boost switching unit that 3rd diode and switched inductors unit are constituted, the second metal-oxide-semiconductor, the second electric capacity, second diode, output diode D_o, output filter capacitor and load R_L.As the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂When simultaneously turning on, described first diode D₁, the second diode D₂, the 3rd diode D₃With the 5th diode D₅It is turned off, the 4th diode D₄, the 6th diode D₆Conducting；Described voltage source V_iWith the first electric capacity C₁Together to the first inductance L in parallel₁With the second inductance L₂Charging energy-storing；Meanwhile, voltage source V_i, the first electric capacity C₁With the second electric capacity C₂Together to output filter capacitor C_fWith load R_LPower supply.As the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂When simultaneously turning off, described first diode D₁, the second diode D₂, the 3rd diode D₃With the 5th diode D₅It is both turned on, the 4th diode D₄, the 6th diode D₆With output diode D_oTurn off；First inductance L₁With the second inductance L₂With the first electric capacity C after series connection₁Parallel connection, forms loop；Described voltage source V_iWith the first inductance L₁With the second inductance L₂Together to the second electric capacity C₂Charging, forms loop；Meanwhile, output filter capacitor C_fTo load R_LIt is powered.Whole circuit structure is simple, has higher output voltage gain.

The concrete connected mode of circuit of the present invention is as follows: the positive pole of described voltage source is connected with the negative pole of the first electric capacity and the anode of the 3rd diode respectively；The positive pole of described first electric capacity anode with negative electrode, the drain electrode of the first metal-oxide-semiconductor and the output diode of the first diode respectively is connected；The source electrode of described first metal-oxide-semiconductor anode with negative electrode, one end of the first inductance and the 4th diode of the 3rd diode respectively is connected；The negative electrode of described 4th diode is connected with the negative electrode of the 5th diode and one end of the second inductance respectively；The other end of described first inductance is connected with the anode of the 5th diode and the anode of the 6th diode respectively；The anode of described first diode negative electrode with the other end, the drain electrode of the second metal-oxide-semiconductor, the positive pole of the second electric capacity and the 6th diode of the second inductance respectively is connected；The negative pole of described second electric capacity one end with the anode of the second diode, the negative pole of output filter capacitor and load respectively is connected；The negative electrode of described output diode is connected with the positive pole of output filter capacitor and the other end of load respectively；The negative pole of described voltage source is connected with source electrode, the negative electrode of the second diode of the second metal-oxide-semiconductor respectively.

Fig. 2 a, Fig. 2 b give the process chart of circuit of the present invention.Fig. 2 a, Fig. 2 b correspondence respectively is the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂Simultaneously turn on and simultaneously turn off the equivalent circuit diagram of period.Having the part that electric current flows through during solid line represents changer in figure, dotted line represents the part that in changer, no current flows through.

The work process of the present invention is as follows:

Stage 1, such as Fig. 2 a: the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂Simultaneously turn on, now the first diode D₁, the second diode D₂, the 3rd diode D₃With the 5th diode D₅It is turned off, the 4th diode D₄, the 6th diode D₆Conducting.Circuit defines two loops, respectively: voltage source V_iWith the first electric capacity C₁With the second electric capacity C₂Give output filter capacitor C together_fWith load R_LCharging, forms loop；Voltage source V_iWith the first electric capacity C₁To the first inductance L in parallel₁With the second inductance L₂It is charged energy storage, forms loop.

Stage 2, such as Fig. 2 the b: the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂Simultaneously turn off, now the first diode D₁, the second diode D₂, the 3rd diode D₃With the 5th diode D₅It is both turned on, the 4th diode D₄, the 6th diode D₆With output diode D_oTurn off.Circuit defines three loops, respectively: voltage source V_iWith the first inductance L₁With the second inductance L₂Give the second electric capacity C together₂Charging energy-storing, forms loop；First inductance L₁With the second inductance L₂Together to the first electric capacity C after series connection₁Charging, forms loop；Output filter capacitor C_fGive load R_LPower supply, forms loop.

To sum up situation, due to the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂Switch triggering pulse identical, if switching tube S₁And S₂Dutycycle be D, switch periods is T_s.And set V_L1And V_L2It is respectively the first inductance L₁With the second inductance L₂The voltage at two ends, V_C1、V_C2It is respectively the first electric capacity C₁With the second electric capacity C₂Voltage, V_S1For and V_S2It is respectively the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂Voltage between drain electrode and source electrode.Switch periods T_sIn, making output voltage is V_o.After changer enters steady operation, draw following voltage relationship derivation.

Operation mode 1: the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂Simultaneously turn on, shown in corresponding equivalent circuit diagram 2a, therefore have an equation below:

V_L1on=V_L2on=V_i+V_C1 (1)

V_O=V_i+V_C1+V_C2 (2)

V_S1=V_S2=0 (3) metal-oxide-semiconductor S₁And S₂ON time be DT_s。

Operation mode 2: the first metal-oxide-semiconductor S₁With the second metal-oxide-semiconductor S₂Being turned off, corresponding equivalent circuit as shown in Figure 2 b, therefore has an equation below:

V_L1-off+V_L2-off=-V_C1

(4)

V_L1-off+V_L2-off=V_i-V_C2 (5)

V_S2=V_C2 (6)

V_S1=V_C1 (7)

Metal-oxide-semiconductor S₁And S₂Turn-off time be (1-D) T_s。

Analyze according to above, the first inductance L1 and the second inductance L2 use inductance Flux consumption conservation principle, simultaneous formula (1), formula (4), formula (5) can obtain respectively:

D(V_i+V_C1)-(1-D)(V_C1+V_L2-off)=0 (8)

D(V_i+V_C1)-(1-D)(V_C1+V_L1-off)=0 (9) simultaneous formula (8) and formula (9) can be tried to achieve:

$V_{L1\_off}=V_{L2\_off}=-\frac{V_{C1}}{2}---\left(10\right)$

Thus, simultaneous formula (8), formula (9) and formula (10) can draw the first electric capacity C₁Voltage V_C1, the second electric capacity C₂Voltage V_C2With voltage source V_iBetween relational expression be:

$V_{C1}=\frac{2D}{1-3D}{V}_i---\left(11\right)$

$V_{C2}=\frac{1-D}{1-3D}{V}_i---\left(12\right)$

Then by formula (2), formula (11) and formula (12), the output voltage V of circuit of the present invention can be obtained_oExpression formula is:

$V_o=\frac{2(1-D)}{1-3D}{V}_i---\left(13\right)$

The expression formula of the output voltage gain of circuit the most of the present invention is:

$G=\frac{V_o}{V_i}=\frac{2(1-D)}{1-3D}---\left(14\right)$

It is illustrated in figure 3 gain curve and Boost, switching capacity Boost, traditional Z source DC-DC converter and the gain curve comparison diagram of novel quasi-Z source DC-DC converter of circuit of the present invention, figure includes the gain curve of circuit of the present invention, the gain curve of novel quasi-Z source DC-DC converter, the gain curve of traditional Z source DC-DC converter, the gain curve of switching capacity Boost, and the gain curve of Boost.As seen from the figure, circuit of the present invention is in the case of dutycycle D is less than 0.33, and gain G just can reach very big, and dutycycle D of circuit of the present invention is not over 0.33.Therefore, by contrast, the gain of circuit of the present invention is the highest.

In sum, circuit overall structure of the present invention is simple, easy to control, combine the characteristic of quasi-boost switching unit single-stage buck and switched inductors and switching capacity charges the characteristic of discharged in series parallel, achieve the further lifting of output voltage gain, and there is not inrush current and metal-oxide-semiconductor opens the dash current of moment.

Above-described embodiment is the present invention preferably embodiment; but embodiments of the present invention are also not restricted by the embodiments; the change made under other any spirit without departing from the present invention and principle, modify, substitute, combine, simplify; all should be the substitute mode of equivalence, within being included in protection scope of the present invention.

Claims (3)

1. A switched inductance type quasi-switch boost DC-DC converter circuit, characterized in that it includes a voltage source (V _i ), a switched inductance unit, a quasi-switch boost unit, a second MOS tube (S ₂ ), a second Capacitor (C ₂ ), second diode (D ₂ ), output diode (D _o ), output filter capacitor (C _f ) and load (R _L ); the switch inductance unit consists of first inductor (L ₁ ), The second inductor (L ₂ ), the fourth diode (D ₄ ), the fifth diode (D ₅ ), and the sixth diode (D ₆ ); the quasi-switching boost unit consists of the first two Pole transistor (D ₁ ), first capacitor (C ₁ ), first MOS transistor (S ₁ ), third diode (D ₃ ) and the aforementioned switching inductance unit. 2. A switched inductance type quasi-switching step-up DC-DC converter circuit according to claim 1, characterized in that the positive pole of the voltage source (V _i ) is connected to the negative pole of the first capacitor (C ₁ ) and The anode of the third diode (D ₃ ) is connected; the anode of the first capacitor (C ₁ ) is respectively connected to the cathode of the first diode (D ₁ ), the drain of the first MOS transistor (S ₁ ) and The anode of the output diode (D _o ) is connected; the source of the first MOS transistor (S ₁ ) is connected to the cathode of the third diode (D ₃ ), one end of the first inductor (L ₁ ) and the fourth two The anode of the diode (D ₄ ) is connected; the cathode of the fourth diode (D ₄ ) is respectively connected with the cathode of the fifth diode (D ₅ ) and one end of the second inductor (L ₂ ); the The other end of the first inductor (L ₁ ) is respectively connected to the anode of the fifth diode (D ₅ ) and the anode of the sixth diode (D ₆ ); the anode of the first diode (D ₁ ) respectively connected to the other end of the second inductor (L ₂ ), the drain of the second MOS transistor (S ₂ ), the anode of the second capacitor (C ₂ ) and the cathode of the sixth diode (D ₆ ); The cathode of the second capacitor (C ₂ ) is respectively connected to the anode of the second diode (D ₂ ), the cathode of the output filter capacitor (C _f ) and one end of the load ( _RL ); the output diode (D _o ) The cathode of the output filter capacitor (C _f ) and the other end of the load ( _RL ) are respectively connected; the negative electrode of the voltage source (V _i ) is respectively connected to the source of the second MOS tube (S ₂ ), the second Cathode connection of diode (D ₂ ). 3. A switch inductance type quasi-switch step-up DC-DC converter circuit according to claim 1, characterized in that when the first MOS transistor (S ₁ ) and the second MOS transistor (S ₂ ) are turned on at the same time , the first diode (D ₁ ), the second diode (D ₂ ), the third diode (D ₃ ) and the fifth diode (D ₅ ) are all off, the fourth diode The tube (D ₄ ) and the sixth diode (D ₆ ) conduct, the voltage source (V _i ) and the first capacitor (C ₁ ) give the parallel connection of the first inductor (L ₁ ) and the second inductor (L ₂ ) At the same time, the voltage source (V _i ) supplies power to the output filter capacitor (C _f ) and the load (R _L ) together with the first capacitor (C ₁ ) and the second capacitor (C ₂ ); when the first MOS tube ( When S ₁ ) and the second MOS transistor (S ₂ ) are turned off at the same time, the first diode (D ₁ ), the second diode (D ₂ ), the third diode (D ₃ ) and the The five diodes (D ₅ ) are all turned on, the fourth diode (D ₄ ) and the sixth diode (D ₆ ) are turned off, and the output diode (D _o ) is turned off; the first inductor (L ₁ ) and the second inductance (L ₂ ) are connected in parallel with the first capacitor (C ₁ ) in series to form a loop; the voltage source (V _i ), the first inductance (L ₁ ) and the second inductance (L ₂ ) give The second capacitor (C ₂ ) is charged; at the same time, the output filter capacitor (C _f ) supplies power to the load ( _RL ).