CN203840193U - Circuit for eliminating secondary ripple of single-phase PWM rectifier - Google Patents

Abstract

The utility model discloses a circuit for eliminating secondary ripple of a single-phase PWM rectifier, which comprises an alternating-current side, a converter and a direct-current side, wherein the alternating-current side is connected with the converter through an inductor, the other side of the converter is connected with the direct-current side, a capacitor C2 is connected between the input end of the alternating-current side and a negative electrode end of the direct-current side, and a capacitor C1 is connected between the input end of the alternating-current side and a positive electrode end of the direct-current side. Compared with an original H-bridge converter, the circuit provided by the utility model divides filter inductance at the alternating-current side into two parts, and a capacitance bridge arm is additionally arranged, thereby not only being used for absorbing power of the secondary ripple, but also playing a role of supporting direct-current bus voltage, and achieving purposes of reducing the secondary ripple at the direct-current side and replacing a large capacitor at the direct-current side.

Description

A kind of Single-phase PWM Rectifier is eliminated secondary ripple circuit

Technical field

The utility model relates to a kind of Single-phase PWM Rectifier and eliminates secondary ripple circuit.

Background technology

In middle low power occasion, Single-phase PWM Rectifier obtains applying very widely.Existing most widely used PWM rectifier is the parallel operation of H bridging shown in Fig. 1, but when AC voltage is for exchanging, when input current is the interchange of same frequency, DC side can produce secondary ripple, this ripple can be to the DC side quality of power supply, the stability of system, and all can cause adverse influence in useful life of DC side equipment etc.Traditional solution is in the very large capacitor C of DC side parallel _dc, be used for suppressing secondary ripple, but the method can cause the volume of whole converter to increase, cost rises, and the power density of system reduces greatly.And the method can only suppress to eliminate the secondary ripple of DC side, when DC voltage is higher or when higher to DC voltage required precision, the volume of whole converter and cost more can significantly rise.

To this, document and utility model propose corrective measure to above-mentioned H bridge translation circuit, for example, in periodical " IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS " 1997, the 44th volume, the 4th phase, in the 447th to 455 pages, publication " A Unity Power Factor PWM Rectifier with DC Ripple Compensation " literary composition (author Toshihisa Shimizu etc.) proposes, at the additional one group of switching tube brachium pontis of H bridging parallel operation DC side, secondary ripple energy to be stored in to AC filter capacitor; Periodical " IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS " 2000, the 36th volume, the 5th phase, in the 1419th to 1429 pages, publication " DC Ripple Current Reduction on a Single-Phase PWM Voltage-Source Rectifier " literary composition (author Toshihisa Shimizu etc.) proposes at the additional one group of switching tube brachium pontis of H bridging parallel operation DC side, and two ripple energy are stored in additional inductor.The patent No. is that the Canadian Patent of CA02732525 proposes a kind of method of subduing DC side secondary ripple, at the two-way chopper circuit of H bridging parallel operation DC side parallel, and can be by this secondary ripple power storage in additional capacitor; 96-102 page publication " Decoupling of Fluctuating Power in Single-Phase Systems Through a Symmetrical Half-Bridge Circuit " literary composition (author Yi Tang etc.) of concentrating at the meeting paper of international conference " Applied Power Electronics Conference and Exposition2014 " proposes at the additional one group of switch brachium pontis of H bridging parallel operation DC side, an inductance and an electric capacity brachium pontis, by secondary ripple power storage among electric capacity brachium pontis, as shown in Figure 2.

Above-mentioned four kinds of methods are and are not changing on the basis of original H bridge translation circuit, at converter DC side extra switch pipe, and add energy storage device, thereby make secondary ripple power storage in energy storage device by controlling extra switch pipe, they all can reduce the DC bus capacitor C of converter _dc, the power density of system is raise, volume reduces.But above four kinds of methods all need additionally to add two switching tubes, have greatly increased cost and the out of order probability of system of converter, and because extra switch pipe exists switching loss and conduction loss, thereby greatly reduce the efficiency of converter.

In the application documents that are CN201210545899.6 in the patent No., proposing a kind of uses the PWM rectification circuit secondary ripple of four switching tubes to eliminate circuit, but the direct voltage utilance of this circuit is lower, it is the peak value that DC voltage need to be much higher than AC voltage, therefore greatly reduced its applicable scope, and also can have a negative impact to the efficiency of converter.

Utility model content

The utility model is in order to address the above problem, and proposed a kind of Single-phase PWM Rectifier and eliminated secondary ripple circuit, and it has and absorbs secondary ripple power with electric capacity, thereby reaches the advantage of subduing DC side secondary ripple.

To achieve these goals, the utility model adopts following technical scheme:

A kind of Single-phase PWM Rectifier is eliminated secondary ripple circuit, comprises AC, converter and DC side, and described AC is connected with converter by inductance, and the opposite side of converter is connected with DC side, is connected with capacitor C at AC input and DC side negative pole end ₂, be connected with capacitor C at AC input and DC side positive terminal ₁.

Described AC is divided into the first interchange end and exchanges end with second, described converter comprises A phase brachium pontis, B phase brachium pontis and electric capacity brachium pontis in parallel, first exchanges end is connected with the A phase brachium pontis of converter by inductance L 2, second exchanges end is connected with electric capacity brachium pontis, and electric capacity brachium pontis is connected with B phase brachium pontis by inductance L 1.

Described A phase brachium pontis is made up of the switching tube S1 connecting and switching tube S2, B phase brachium pontis is made up of the switching tube S3 connecting and switching tube S4, electric capacity brachium pontis is made up of the capacitor C 1 of connecting and capacitor C 2, the tie point of switching tube S1 and switching tube S2 is connected with inductance L 2, the tie point of switching tube S3 and switching tube S4 is connected with inductance L 1, and the tie point of capacitor C 1 and capacitor C 2 exchanges end with second tie point with inductance L 1 is connected.

Described switching tube S1, switching tube S2, switching tube S3 and switching tube S4 are field effect transistor or gated transistor.

The beneficial effects of the utility model are:

The circuit that the utility model provides is than traditional H bridge translation circuit, add electric capacity brachium pontis, both, for absorbing secondary ripple power, played again the effect that DC bus-bar voltage directly supports, subdue DC side secondary ripple thereby both reached, substituted again the object of the large electric capacity of original DC side.

Compared with the H bridge translation circuit shown in Fig. 1, although the utility model needs an electric capacity brachium pontis, but required capacitor C 1 and the value of C2 value sum much smaller than the required DC bus capacitor of original H bridge translation circuit, and required capacitor C 1 is also less than H bridge translation circuit DC bus capacitor with the withstand voltage of C2, will greatly reduce like this use of electric capacity in converter, the volume of whole converter is reduced greatly, and cost declines greatly; Moreover, the utility model can also be subdued the secondary ripple of DC side, subdue the impact of original secondary ripple on DC side equipment, especially when higher at DC voltage or higher to DC voltage required precision, the utility model is at volume, and the aspect advantages such as cost and power density are more obvious.

Compared with circuit shown in Fig. 2, the utility model has been realized the function in energy-storage travelling wave tube by secondary ripple power storage equally, subdue the secondary ripple of direct current, high in the power density with Fig. 2 circuit, when the advantages such as volume is little, than Fig. 2 circuit, the utility model also has the following advantages:

A. the utility model is saved two switching tubes.Due to a series of auxiliary circuits or devices such as each switching tube demand motive, protection, buffer circuit and heat abstractors; these devices and switching tube itself all can take volume; produce loss; increase system fault probability, and switching tube work time can produce conducting and switching loss, the loss of switching tube is topmost loss in converters; therefore having saved switching tube can make the loss of converter greatly decline; cost declines greatly, and volume reduces, and stability also can increase.

B. the utility model is divided into two original H bridging parallel operation AC filter inductance, is divided into two inductance of L1 and L2, because two inductance all play the function of filtering AC switching harmonics.Therefore than the bridge of H shown in Fig. 1 translation circuit, the utility model is without additional inductor, and than circuit shown in Fig. 2, the utility model is saved an additional inductor.

Than circuit shown in Fig. 3, the utility model has adopted four switching tubes just can realize secondary ripple power storage in the function of energy-storage travelling wave tube equally, in the high efficiency with Fig. 3 circuit, when low cost, also has the following advantages:

A. the utility model has also been saved DC bus capacitor C _dcthereby, further reduced the use of electric capacity in converter.

B. the utility model can significantly increase converter direct voltage utilance, and DC voltage value no longer needs the significantly peak value higher than alternating voltage, thereby converter of the present utility model has wider range of application, and has higher efficiency.

Than the bridge of H shown in Fig. 1 translation circuit, the utility model has substituted DC bus capacitor with electric capacity brachium pontis, in order to absorb secondary ripple power, thereby can reach the object of subduing DC side secondary ripple.The utility model has reduced the bridge of H shown in Fig. 1 translation circuit DC bus capacitor value, has reduced volume and the cost of converter, also can produce Beneficial Effect to the life-span of DC side equipment; Than circuit shown in Fig. 2, the utility model has been saved two switching tubes and an inductance, thereby has reduced converter cost, loss and volume, and has strengthened the stability of system.Shown in Fig. 3, the utility model has not only been saved DC bus capacitor but also has been increased its direct voltage utilance, thereby has wider range of application, and has higher efficiency.

Brief description of the drawings

Fig. 1 is existing H bridging parallel operation topological structure

Fig. 2 is that existing 6 switching tubes are subdued DC side secondary ripple single-phase invertor circuit topology;

Fig. 3 is that existing 4 switching tubes are subdued DC side secondary ripple single-phase invertor circuit topology;

Fig. 4 is topological structure of the present utility model;

Fig. 5 is that the voltage v with respect to positive DC side end is held in the first interchange in the time of device steady operation _d, electric capacity brachium pontis mid-point voltage v _c, AC voltage v _acwaveform.

Wherein, 1. AC, 2. converter, 3. DC side, 4. electric capacity brachium pontis, 5.A phase brachium pontis, 6.B phase brachium pontis, 7. AC power or load, 8. DC power supply or load.

Embodiment:

Below in conjunction with accompanying drawing and embodiment, the utility model is described in further detail.

As shown in Figure 4, a kind of single-phase voltage code converter is eliminated secondary ripple circuit, and it comprises AC 1, converter 2 and DC side 3, and described AC 1 is connected with converter 2 by inductance, and the opposite side of converter 2 is connected with DC side 3.

Described AC 1 is divided into the first interchange end and exchanges end with second, described converter 2 comprises electric capacity brachium pontis 4 in parallel, A phase brachium pontis 5 and B phase brachium pontis 6, first exchanges end is connected with the A phase brachium pontis 5 of converter 2 by inductance L 2, second exchanges end is connected with electric capacity brachium pontis 4, and electric capacity brachium pontis 4 is connected with B phase brachium pontis 6 by inductance L 1.Described AC comprises AC power or load 7, and AC power or load 7 one sides are connected with inductance L 2, and opposite side is connected with inductance L 1, and described DC side 3 comprises DC power supply or load 8.

Described A phase brachium pontis is made up of the switching tube S1 connecting and switching tube S2, B phase brachium pontis is made up of the switching tube S3 connecting and switching tube S4, electric capacity brachium pontis is made up of the capacitor C 1 of connecting and capacitor C 2, the tie point of switching tube S1 and switching tube S2 is connected with inductance L 2, the tie point of switching tube S3 and switching tube S4 is connected with inductance L 1, and the tie point of capacitor C 1 and capacitor C 2 exchanges end with second tie point with inductance L 1 is connected.

Described switching tube S1, switching tube S2, switching tube S3 and switching tube S4 are field effect transistor or gated transistor.

Be illustrated in figure 1 existing H bridging converter circuit; Fig. 2 is that existing 6 switching tubes are subdued DC side secondary ripple single-phase invertor circuit topology; Fig. 3 is that existing 4 switching tubes are subdued DC side secondary ripple single-phase invertor circuit topology;

As shown in Figure 4, when AC 1 voltage is for exchanging, when interchange that input current is same frequency, the expression formula of its voltage, electric current is as follows:

v _ac＝Vsinωt (1)

V and I are respectively input voltage, the peak value of electric current, and ω is angular frequency, t is the time, for the angle between voltage and electric current, i.e. power-factor angle, ignore and input the energy storage of inductance and the loss of switching tube, AC 1 instantaneous power, is it and flows into the instantaneous power of DC side 3, has instantaneous power expression formula to be:

P _acfor AC 1 flows into the instantaneous power of DC side 3.Can find out that from formula (3) it is average power p that inflow DC side instantaneous power not only comprises DC component _o, and to contain quadratic component be ripple power p _r, they are respectively:

Can be found out by formula (4), when time, po > 0, power is flowed to DC side by AC, and this converter works in rectification state; When time, p _o< 0, power is flowed to AC by DC side, and this converter works in inverter mode; When time, p _o=0, DC side and AC only have idle exchange, and this converter works in static reacance generation state.

If electric capacity brachium pontis two capacitor's capacities equate, i.e. C ₁=C ₂=C _f, in the time of circuit steady operation, the voltage of two electric capacity is sentenced sinusoidal fluctuation in DC voltage half, and two capacitance voltage sums are DC voltage value, and its voltage fluctuation equation is as formula (6) institute

$\left\{\begin{array}{c}{v}_{c1}=\frac{c_{\mathrm{dc}}}{2}+V_c\sin (\mathrm{\&omega;}+\mathrm{\&theta;})\\ v_{c2}=\frac{v_{\mathrm{dc}}}{2}-V_c\sin (\mathrm{\&omega;t}+\mathrm{\&theta;})\end{array}\right.---\left(6\right)$

In formula, v _c1with v _c2represent respectively capacitor C ₁with C ₂voltage, v _dcfor DC voltage, V _cfor capacitance fluctuations peak value, and V _c< v _dc/ 2, θ is the angle of its fluctuation voltage and input voltage., according to formula (6), can draw the electric current of two electric capacity, as shown in formula (7):

$\left\{\begin{array}{c}{i}_{c1}=\mathrm{\&omega;}{C}_f{V}_c\cos (\mathrm{\&omega;t}+\mathrm{\&theta;})\\ i_{c2}=-\mathrm{\&omega;}{C}_f{V}_c\cos (\mathrm{\&omega;t}+\mathrm{\&theta;})\end{array}---\left(7\right)\right.$

The instantaneous power p of two capacitive absorptions _cas shown in formula (8):

$P_c=\mathrm{\&omega;}{C}_f{V}_c^2\sin (2\mathrm{\&omega;t}+2\mathrm{\&theta;})---\left(8\right)$

From formula (8), the power that electric capacity brachium pontis absorbs is also twice power.As ignore the energy storage of inductance, the power p absorbing when electric capacity brachium pontis shown in dominated formulate (8) _cequal twice ripple power p of system shown in formula (5) _rtime, twice ripple power of system is absorbed by electric capacity brachium pontis completely.

Illustrate the working method of this circuit below: make power-factor angle be circuit working in unit power factor rectifier state, equate with formula (5) according to formula (8), obtain θ=-π/4+k π, k is integer.Make θ=-π/4, DC voltage v _dc=450V, the capacitance fluctuations peak value V in formula (6) _c=190V, can show that according to formula (6) two voltage fluctuation of capacitor equations are formula (9).

$\left\{\begin{array}{c}{v}_{c1}=225+190\sin (\mathrm{\&omega;t}-\mathrm{\&pi;}/4)\\ v_{c2}=225-190\sin (\mathrm{\&omega;t}-\mathrm{\&pi;}/4)\end{array}\right.---\left(9\right)$

Ignore two pressure drops on inductance, and the current potential of establishing positive DC side end is 0V, the current potential that in Fig. 4, C point is ordered with B equates, is equal to capacitor C ₂voltage, its relation is as shown in formula (10):

v _B＝v _C＝v _c2＝225-190sin(ωt-π/4) (10)

If alternating voltage peak V=300V is known according to circuit diagram, the current potential that D is ordered is C point current potential v _cwith AC voltage v _acsum, and the current potential that D point is ordered with A equates, as shown in formula (11):

v _A＝v _D＝v _C+v _ac＝225-190sin(ωt-π/4)+300sin(ωt) (11)

In Fig. 5, draw C point voltage v _c, D point voltage v _dand AC voltage v _acoscillogram.From Fig. 4 circuit, D point voltage v _dshould be less than DC voltage v _dcjust make circuit controlled, in the time of design circuit, need ensure v _dmaximum be less than v _dc, v _dminimum value be greater than 0.From Fig. 5 oscillogram, can find out, under institute's setting parameter above, D point voltage meets the demands.

Due to, in the time that DC side is 450V, the alternating voltage peak of the utility model circuit can reach 300V.And in circuit shown in Fig. 3, the patent specification that is CN201210545899.6 according to the patent No., in the time that its DC voltage is similarly 450V, its alternating voltage peak meeting the demands can only reach 150V.Therefore, circuit of the present utility model is than circuit shown in Fig. 3, and its direct voltage utilance has improved approximately one times, thereby the utlity model has wider range of application, and has higher efficiency.

By reference to the accompanying drawings embodiment of the present utility model is described although above-mentioned; but the not restriction to the utility model protection range; one of ordinary skill in the art should be understood that; on the basis of the technical solution of the utility model, those skilled in the art do not need to pay various amendments that creative work can make or distortion still in protection range of the present utility model.

Claims (4)

1. a Single-phase PWM Rectifier is eliminated secondary ripple circuit, it is characterized in that: comprise AC, converter and DC side, described AC is connected with converter by inductance, and the opposite side of converter is connected with DC side, is connected with capacitor C at AC input and DC side negative pole end ₂, be connected with capacitor C at AC input and DC side positive terminal ₁.

2. a kind of Single-phase PWM Rectifier as claimed in claim 1 is eliminated secondary ripple circuit, it is characterized in that: described AC is divided into the first interchange end and exchanges end with second, described converter comprises A phase brachium pontis, B phase brachium pontis and electric capacity brachium pontis in parallel, first exchanges end is connected with the A phase brachium pontis of converter by inductance L 2, second exchanges end is connected with electric capacity brachium pontis, and electric capacity brachium pontis is connected with B phase brachium pontis by inductance L 1.

3. a kind of Single-phase PWM Rectifier as claimed in claim 1 is eliminated secondary ripple circuit, it is characterized in that: described A phase brachium pontis is made up of the switching tube S1 connecting and switching tube S2, B phase brachium pontis is made up of the switching tube S3 connecting and switching tube S4, electric capacity brachium pontis is made up of the capacitor C 1 of connecting and capacitor C 2, the tie point of switching tube S1 and switching tube S2 is connected with inductance L 2, the tie point of switching tube S3 and switching tube S4 is connected with inductance L 1, and the tie point of capacitor C 1 and capacitor C 2 exchanges end with second tie point with inductance L 1 is connected.

4. a kind of Single-phase PWM Rectifier as claimed in claim 1 is eliminated secondary ripple circuit, it is characterized in that: described switching tube S1, switching tube S2, switching tube S3 and switching tube S4 are field effect transistor or gated transistor.