CN205847086U - A kind of switching capacity type high-gain quasi-Z source DC DC changer - Google Patents

Abstract

This utility model provides a kind of switching capacity type high-gain quasi-Z source DC DC converter circuit, including voltage source, by the first electric capacity, the first diode, the first inductance, second inductance, the two ends quasi-Z source unit that 3rd electric capacity is constituted, the switching capacity unit being made up of the second electric capacity, the second diode, a metal-oxide-semiconductor, output diode, output filter capacitor and load.The whole circuit structure of this utility model is simple, combines quasi-Z source unit single-stage buck characteristic and switching capacity charges the characteristic of discharged in series parallel, it is achieved that the expansion of changer output voltage gain.

Description

A kind of switching capacity type high-gain quasi-Z source DC-DC converter

Technical field

This utility model relates to Power Electronic Circuit technical field, is specifically related to a kind of switching capacity type high-gain quasi-Z source DC-DC converter circuit.

Background technology

In fuel cell power generation, photovoltaic generation, due to single solaode or single fuel cell provide straight Stream voltage is relatively low, it is impossible to meets the need for electricity of existing electrical equipment, can not meet grid-connected demand, generally requires multiple Battery is together in series the voltage reaching required.On the one hand this method greatly reduces the reliability of whole system, on the other hand Also need 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.Closely The Z source converter proposed for several years is a kind of high-gain DC-DC converter, but this circuit has higher impedance network capacitance voltage Stress, and during circuit start, there is the biggest inrush current problem, limit the application in practice of this circuit.In order to enter one Step improves the output voltage of Z source converter, it is necessary to is improved by topology and expands its output voltage gain.

Utility model content

The purpose of this utility model is to overcome above-mentioned the deficiencies in the prior art, it is provided that a kind of switching capacity type high-gain Quasi-Z source DC-DC converter circuit, concrete technical scheme is as follows.

A kind of switching capacity type high-gain quasi-Z source DC-DC converter circuit, including voltage source, by the first electric capacity, the one or two Pole is managed, the first inductance, the second inductance, the two ends quasi-Z source unit that the 3rd electric capacity is constituted, and is made up of the second electric capacity, the second diode Switching capacity unit, a metal-oxide-semiconductor, output diode D_o, output filter capacitor and load.Described quasi-Z source unit is by first Inductance, the first diode, the first electric capacity, the second inductance and the 3rd electric capacity are constituted；Described switching capacity unit by the second electric capacity and Second diode is constituted.

In above-mentioned a kind of switching capacity type high-gain quasi-Z source DC-DC converter circuit, the positive pole of described voltage source is respectively It is connected with the negative pole of the first electric capacity and one end of the first inductance；The positive pole of described first electric capacity respectively with the moon of the first diode The anode of pole, one end of the second inductance and output diode connects；The anode of described first diode respectively with the 3rd electric capacity The other end of negative pole and the first inductance connects；The positive pole of described 3rd electric capacity respectively with the other end, the leakage of metal-oxide-semiconductor of the second inductance Pole, the positive pole of the second electric capacity connect；The negative pole of described second electric capacity respectively with the anode of the second diode, output filter capacitor One end of negative pole and load connects；The negative electrode of described output diode respectively with another of the positive pole of output filter capacitor and load End connects；The negative pole of described voltage source is connected with source electrode, the negative electrode of the second diode of metal-oxide-semiconductor respectively.

Compared with prior art, this utility model circuit has the advantage that and technique effect: the whole electricity of this utility model Line structure is simple, has only used a metal-oxide-semiconductor, and easy to control, output voltage gain is higher；This utility model circuit is combined with The single-stage buck characteristic of quasi-Z source unit and switching capacity charge the characteristic of discharged in series parallel, thus increase output voltage, Achieve the expansion of quasi-Z source DC-DC converter output voltage gain.

Accompanying drawing explanation

Fig. 1 is a kind of switching capacity type high-gain quasi-Z source DC-DC converter electricity in this utility model detailed description of the invention Road.

Fig. 2 a, Fig. 2 b are that a kind of switching capacity type high-gain quasi-Z source DC-DC converter circuit shown in Fig. 1 is at its MOS respectively The equivalent circuit diagram of pipe S turn-on and turn-off period.

Fig. 3 a is gain curve and Boost, switching capacity Boost, the traditional Z of this utility model circuit Source DC-DC converter and the gain curve comparison diagram of novel quasi-Z source DC-DC converter.

Fig. 3 b is the gain curve of this utility model circuit and Boost, switching capacity Boost conversion in Fig. 3 a The comparison in dutycycle D is less than 0.5 of the gain curve of device, traditional Z source DC-DC converter and novel quasi-Z source DC-DC converter Figure.

Detailed description of the invention

The technical solution of the utility model is explained in detail by above content, new to this practicality below in conjunction with accompanying drawing Being embodied as of type is further described.

Reference Fig. 1, a kind of switching capacity type high-gain quasi-Z source described in the utility model DC-DC converter circuit, including Voltage source, by the first electric capacity, the first diode, the first inductance, the second inductance, the two ends quasi-Z source unit that the 3rd electric capacity is constituted, by The switching capacity unit that second electric capacity, the second diode are constituted, a metal-oxide-semiconductor, output diode D_o, output filter capacitor is with negative Carry.Described quasi-Z source unit is made up of the first inductance, the first diode, the first electric capacity, the second inductance and the 3rd electric capacity；Described open Close capacitor cell to be made up of the second electric capacity and the second diode.When metal-oxide-semiconductor S turns on, described first diode D₁, the two or two pole Pipe D₂It is turned off, voltage source V_iWith the first electric capacity C₁To the second inductance L₂Charging；Voltage source V_iWith the 3rd electric capacity C₃With the first inductance L₁Charging；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.When When metal-oxide-semiconductor S turns off, described first diode D₁, the second diode D₂It is both turned on, output diode D_oTurn off.Described first inductance L₁With the first electric capacity C₁Parallel connection, forms loop；Described second inductance L₂With the 3rd electric capacity C₃Parallel connection, forms loop；Described voltage source V_i, the first inductance L₁With the second inductance L₂To the second electric capacity C₂Charging；Meanwhile, output filter capacitor C_fGive load R_LPower supply.Whole Circuit structure is simple, has higher output voltage gain.

The concrete connected mode of this utility model circuit is as follows: the positive pole of described voltage source respectively with the negative pole of the first electric capacity Connect with one end of the first inductance；The positive pole of described first electric capacity respectively with negative electrode, one end of the second inductance of the first diode Connect with the anode of output diode；The anode of described first diode another with the negative pole of the 3rd electric capacity and the first inductance respectively One end connects；The positive pole of described 3rd electric capacity respectively with the other end of the second inductance, the drain electrode of metal-oxide-semiconductor, the positive pole of the second electric capacity Connect；The negative pole of described second electric capacity respectively with the anode of the second diode, the negative pole of output filter capacitor and one end of load Connect；The negative electrode of described output diode is connected with the positive pole of output filter capacitor and the other end of load respectively；Described voltage The negative pole in source is connected with source electrode, the negative electrode of the second diode of metal-oxide-semiconductor respectively.

Fig. 2 a, Fig. 2 b give the process chart of this utility model circuit.Fig. 2 a, Fig. 2 b correspondence respectively is metal-oxide-semiconductor S 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.

Work process of the present utility model is as follows:

Stage 1, as Fig. 2 a:MOS pipe S turns on, now the first diode D₁, the second diode D₂, be turned off.Circuit is formed Three loops, respectively: voltage source V_iWith the first electric capacity C₁With the second electric capacity C₂Give output filter capacitor C together_fWith load R_L Charging, forms loop；Voltage source V_iWith the first electric capacity C₁To the second inductance L₂It is charged, forms loop；Voltage source V_iWith the 3rd Electric capacity C₃To the first inductance L₁It is charged, forms loop.

Stage 2, as Fig. 2 b:MOS pipe S turns off, now the first diode D₁, the second diode D₂It is both turned on, output diode D_oTurn off.Circuit defines four loops, respectively: voltage source V_i, the first inductance L₁With the second inductance L₂To the second electric capacity C₂Fill Electricity, forms loop；First inductance L₁To the first electric capacity C₁Charging, forms loop；Second inductance L₂To the 3rd electric capacity C3 charging, shape Become loop；Output filter capacitor C_fGive load R_LPower supply, forms loop.

To sum up situation, if the dutycycle of metal-oxide-semiconductor S is D, switch periods is T_s.And set V_L1And V_L2It is respectively inductance L₁ And L₂The voltage at two ends, V_C1、V_C2And V_C3It is respectively the first electric capacity C₁, the second electric capacity C₂With the 3rd electric capacity C₃Voltage, V_SFor MOS Voltage between pipe S drain electrode and source electrode.Switch periods T_sIn, making output voltage is V_o.When changer enters steady operation After, draw following voltage relationship derivation.

Operation mode 1:MOS pipe S turns on, and shown in corresponding equivalent circuit diagram 2a, therefore has an equation below:

V_L1=V_i+V_C3 (1)

V_L2=V_i+V_C1 (2)

V_O=V_i+V_C1+V_C2 (3)

V_S=0 (4)

The ON time of metal-oxide-semiconductor S is DT_s。

Operation mode 2:MOS pipe S turns off, and corresponding equivalent circuit as shown in Figure 2 b, therefore has an equation below:

V_L1=-V_C1 (5)

V_L2=-V_C3 (6)

V_i=V_C2-V_C3-V_C1 (7)

V_S=V_C2 (8)

The turn-off time of metal-oxide-semiconductor S is (1-D) T_s。

Analyze, to the first inductance L according to above₁With the second inductance L₂Use inductance Flux consumption conservation principle, simultaneous formula respectively (1), formula (2), formula (5), formula (6) can obtain:

D(V_i+V_C3)-(1-D)V_C1=0 (9)

D(V_i+V_C1)-(1-D)V_C3=0 (10)

The first electric capacity C can be obtained by formula (7), formula (9) and formula (11)₁Voltage V_C1, the second electric capacity C₂Voltage V_C2With 3rd electric capacity C₃Voltage V_C3With voltage source V_iBetween relational expression be:

$V_{C1}=V_{C3}=\frac{D}{1-2D}{V}_i---\left(11\right)$

$V_{C2}=\frac{1}{1-2D}{V}_i---\left(12\right)$

Then by formula (3), formula (11) and formula (12), the gain factor expression formula that can obtain this utility model circuit is:

$G=\frac{V_o}{V_i}=\frac{2-D}{1-2D}---\left(13\right)$

It is gain curve and Boost, the switching capacity Boost conversion of this utility model circuit as shown in Figure 3 a Device, traditional Z source DC-DC converter and the gain curve comparison diagram of novel quasi-Z source DC-DC converter；Fig. 3 b is this reality in Fig. 3 a With the gain curve of novel circuit gain curve and basic booster circuit comparison diagram in dutycycle D is less than 0.5, figure includes The gain curve of this utility model circuit, the gain curve of novel quasi-Z source DC-DC converter, traditional Z source DC-DC converter Gain curve, the gain curve of switching capacity Boost, and the gain curve of Boost.As seen from the figure, this reality By novel circuit in dutycycle D less than in the case of 0.5, gain G just can reach very greatly, and the accounting for of this utility model circuit Empty than D not over 0.5.Therefore, by contrast, the gain of this utility model circuit is the highest.

In sum, this utility model circuit overall structure is simple, has simply used a metal-oxide-semiconductor, easy to control, combines Quasi-Z source unit single-stage buck characteristic and switching capacity charge the characteristic of discharged in series parallel, it is achieved that output voltage gain Promote further, and there is not inrush current and metal-oxide-semiconductor opens the dash current of moment.

Above-described embodiment is this utility model preferably embodiment, but embodiment of the present utility model is not by described The restriction of embodiment, other any without departing from the change made under spirit of the present utility model and principle, modify, replace In generation, combine, simplify, all should be the substitute mode of equivalence, within being included in protection domain of the present utility model.

Claims (1)

1. a switching capacity type high-gain quasi-Z source DC-DC converter circuit, it is characterised in that include voltage source (V_i), quasi-Z source Unit, metal-oxide-semiconductor (S), switching capacity unit, output diode (D_o), output filter capacitor (C_f) and load (R_L)；Described quasi-Z source Unit is by the first inductance (L₁), the first diode (D₁), the first electric capacity (C₁), the second inductance (L₂) and the 3rd electric capacity (C₃) constitute； Described switching capacity unit is by the second electric capacity (C₂) and the second diode (D₂) constitute；

Described voltage source (V_i) positive pole respectively with the first electric capacity (C₁) negative pole and the first inductance (L₁) one end connect；Described First electric capacity (C₁) positive pole respectively with the first diode (D₁) negative electrode, the second inductance (L₂) one end and output diode (D_o) anode connect；Described first diode (D₁) anode respectively with the 3rd electric capacity (C₃) negative pole and the first inductance (L₁) The other end connect；Described 3rd electric capacity (C₃) positive pole respectively with the second inductance (L₂) the other end, the drain electrode of metal-oxide-semiconductor (S), Second electric capacity (C₂) positive pole connect；Described second electric capacity (C₂) negative pole respectively with the second diode (D₂) anode, output filter Ripple electric capacity (C_f) negative pole and load (R_L) one end connect；Described output diode (D_o) negative electrode respectively with output filtered electrical Hold (C_f) positive pole and load (R_L) the other end connect；Described voltage source (V_i) negative pole respectively with the source electrode of metal-oxide-semiconductor (S), Two diode (D₂) negative electrode connect.