CN103944365B - A kind of Single-phase PWM Rectifier is eliminated secondary ripple circuit - Google Patents

Abstract

The invention discloses a kind of Single-phase PWM Rectifier and eliminate secondary ripple circuit, 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 end₂, be connected with capacitor C at AC input and DC side positive terminal₁. Circuit provided by the invention is than original H bridging parallel operation, AC filter inductance is divided into two, and add electric capacity brachium pontis, both for absorbing secondary ripple power, play 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.

Description

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

Technical field

The present invention relates to a kind of Single-phase PWM Rectifier and eliminate secondary ripple circuit.

Background technology

In middle low power occasion, Single-phase PWM Rectifier obtains applying very widely. Existing most widely used PWM rectificationDevice is the parallel operation of H bridging shown in Fig. 1, but when AC voltage is for exchanging, when interchange that input current is same frequency, DC side meetingProduce secondary ripple, this ripple can be to the DC side quality of power supply, the stability of system, and the service life of DC side equipment etc.Adverse influence is caused in capital. 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, and cost rises, and the power density of system reduces greatly. And, the partyMethod can only suppress to eliminate the secondary ripple of DC side, when DC voltage is higher or higher to DC voltage required precisionTime, the volume of whole converter and cost more can significantly rise.

To this, document proposes corrective measure with invention to above-mentioned H bridge translation circuit, for example, and at periodical " IEEETRANSACTIONSONINDUSTRIALELECTRONICS " 1997 years, the 44th volume, the 4th phase, the 447th to 455Publication " AUnityPowerFactorPWMRectifierwithDCRippleCompensation " literary composition (author in pageToshihisaShimizu etc.) propose at the additional one group of switching tube brachium pontis of H bridging parallel operation DC side, by the storage of secondary ripple energyIn AC filter capacitor; Periodical " IEEETRANSACTIONSONINDUSTRYAPPLICATIONS " 2000,The 36th volume, the 5th phase, publication " DCRippleCurrentReductiononaSingle-Phase in the 1419th to 1429 pagesPWMVoltage-SourceRectifier " literary composition (author ToshihisaShimizu etc.) proposes at H bridging parallel operation DC sideAdditional one group of switching tube brachium pontis, and two ripple energy are stored in additional inductor. The patent No. is the Canada of CA02732525Patent 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 byThis secondary ripple power storage is in additional capacitor; At international conference " AppliedPowerElectronicsConferenceandExposition2014 " the 96-102 page publication " DecouplingofFluctuatingPowerin that concentrates of meeting paperSingle-PhaseSystemsThroughaSymmetricalHalf-BridgeCircuit " literary composition (author YiTang etc.) carriesGo out 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 storageAmong 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 canTo 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 needAdditionally add two switching tubes, greatly increased cost and the out of order probability of system of converter, and because extra switch pipe is depositedAt switching loss and conduction loss, thereby greatly reduce the efficiency of converter.

A kind of PWM rectification that uses four switching tubes proposed in the application documents that are CN201210545899.6 in the patent No.Circuit secondary ripple is eliminated circuit, but the DC voltage utilization rate of this circuit is lower, and DC voltage need to be much higher than interchangeThe peak value of side voltage, has therefore reduced its applicable scope greatly, and also can have a negative impact to the efficiency of converter.

Summary of the invention

The present invention, in order addressing the above problem, to have proposed a kind of Single-phase PWM Rectifier and has eliminated secondary ripple circuit, and it has useElectric capacity absorbs secondary ripple power, thereby reaches the advantage of subduing DC side secondary ripple.

To achieve these goals, the present invention adopts following technical scheme:

A kind of Single-phase PWM Rectifier is eliminated secondary ripple circuit, comprises AC, converter and DC side, described ACBe connected with converter by inductance, the opposite side of converter is connected with DC side, connects at AC input and DC side negative pole endBe connected to capacitor C₂, be connected with capacitor C at AC input and DC side positive terminal₁。

Described AC is divided into the first interchange end and exchanges end with second, and described converter comprises A phase brachium pontis in parallel, B phase brachium pontisWith electric capacity brachium pontis, first exchanges end is connected with the A phase brachium pontis of converter by inductance L 2, and second exchanges end connects with electric capacity brachium pontisConnect, 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, and B phase brachium pontis is by switching tube S3 and the switch of connectingPipe S4 composition, 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 withInductance L 2 connects, and the tie point of switching tube S3 and switching tube S4 is connected with inductance L 1, the tie point of capacitor C 1 and capacitor C 2The tie point that exchanges end with inductance L 1 with second is connected.

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

Beneficial effect of the present invention is:

Circuit provided by the invention, than traditional H bridge translation circuit, adds electric capacity brachium pontis, both for absorbing secondary ripple meritRate, plays again the effect that DC bus-bar voltage directly supports, and subdues DC side secondary ripple thereby both reached, and substitutes again original DC sideThe object of large electric capacity.

Compared with the H bridge translation circuit shown in Fig. 1, although the present invention needs an electric capacity brachium pontis, required capacitor C 1 and C2Value sum is much smaller than the value of the required DC bus capacitor of original H bridge translation circuit, and required capacitor C 1 is also less than with the withstand voltage of C2H bridge translation circuit DC bus capacitor, will greatly reduce the use of electric capacity in converter like this, makes the volume of whole converter largeReduce greatly, cost declines greatly; Moreover, the present invention can also subdue the secondary ripple of DC side, subdues original secondary lineThe impact of ripple on DC side equipment, when especially higher at DC voltage or higher to DC voltage required precision, the present invention existsVolume, the aspect advantages such as cost and power density are more obvious.

Compared with circuit shown in Fig. 2, the present invention has realized the function in energy-storage travelling wave tube by secondary ripple power storage equally, disappearsSubtract the secondary ripple of direct current, to have the power density of Fig. 2 circuit high, when the advantage such as volume is little, than Fig. 2 electricityRoad, the present invention also has the following advantages:

A. the present invention saves two switching tubes. Due to each switching tube demand motive, protection, buffer circuit and heat abstractorEtc. a series of auxiliary circuits or device, these devices and switching tube itself all can take volume, produces loss, the event of increase systemBarrier probability, and switching tube work time can produce conducting and switching loss, and the loss of switching tube is the most main in convertersThe loss of wanting, has therefore saved switching tube and can make the loss of converter greatly decline, and cost declines greatly, and volume reduces, stableProperty also can increase.

B. the present invention is divided into two original H bridging parallel operation AC filter inductance, is divided into two inductance of L1 and L2, due toTwo inductance all play the function of filtering AC switching harmonics. Therefore than the bridge of H shown in Fig. 1 translation circuit, the present invention withoutNeed additional inductor, than circuit shown in Fig. 2, the present invention saves an additional inductor.

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

A. the present invention has also saved DC bus capacitor C_dcThereby, further reduced the use of electric capacity in converter.

B. the present invention can significantly increase converter DC voltage utilization rate, and DC voltage value no longer needs significantly higher than alternating currentThe peak value of pressing, thus converter of the present invention has wider range of application, and there is higher efficiency.

Than the bridge of H shown in Fig. 1 translation circuit, the present invention has substituted DC bus capacitor with electric capacity brachium pontis, in order to absorb secondary ripplePower, thus can reach the object of subduing DC side secondary ripple. The present invention has reduced the bridge of H shown in Fig. 1 translation circuit DC side electricityCapacitance, has reduced volume and the cost of converter, also can produce Beneficial Effect to the life-span of DC side equipment; Shown in Fig. 2Circuit, the present invention has saved two switching tubes and an inductance, thereby has reduced converter cost, loss and volume, and strengthensThe stability of system. Shown in Fig. 3, the present invention has not only saved DC bus capacitor but also has increased its DC voltage utilizationRate, thus wider range of application there is, and there is 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 invention;

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. alternating currentSource or load, 8. dc source or load.

Detailed description of the invention:

Below in conjunction with accompanying drawing and embodiment, the invention will be further described.

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 andDC side 3, 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, and described converter 2 comprises electric capacity brachium pontis 4 in parallel, APhase brachium pontis 5 and B phase brachium pontis 6, the first exchange end and are connected with the A phase brachium pontis 5 of converter 2 by inductance L 2, and second exchangesEnd 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 alternating currentSource or load 7, AC power or load 7 one sides are connected with inductance L 2, and opposite side is connected with inductance L 1, described DC side 3Comprise dc source or load 8.

Described A phase brachium pontis is made up of the switching tube S1 connecting and switching tube S2, and B phase brachium pontis is by switching tube S3 and the switch of connectingPipe S4 composition, 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 withInductance L 2 connects, and the tie point of switching tube S3 and switching tube S4 is connected with inductance L 1, the tie point of capacitor C 1 and capacitor C 2The tie point that exchanges end with inductance L 1 with second is connected.

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

Be illustrated in figure 1 existing H bridging converter circuit; Fig. 2 is that existing 6 switching tubes are subdued the single-phase conversion of DC side secondary rippleDevice 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 table of its voltage, electric currentReach formula 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 folder between voltage and electric currentAngle, i.e. power-factor angle,Ignore and input the energy storage of inductance and the loss of switching tube, AC 1 is instantaneousPower, 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 and flow into DC side instantaneous power not only from formula (3)Comprising DC component is mean power p_o, and to contain quadratic component be ripple power p_r, they are respectively:

Can be found out by formula (4), whenTime, p_o> 0, power is flowed to DC side by AC, this converterWork in rectification state; WhenTime, p_o< 0, power is flowed to AC by DC side, and this converter works inInverter mode; WhenTime, p_o=0, DC side and AC only have idle exchange, and this converter works in quietStop idle generation state.

If electric capacity brachium pontis two capacitor's capacities equate, i.e. C₁＝C₂＝C_f, in the time of circuit steady operation, the voltage of two electric capacity is at direct currentSide voltage half is sentenced sinusoidal fluctuation, and two capacitance voltage sums are DC voltage value, and its voltage pulsation equation is as formula (6) instituteShow:

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

In formula, v_c1With v_c2Represent respectively capacitor C₁With C₂Voltage, v_dcFor DC voltage, V_cFor capacitance fluctuations peak value, andV_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, asShown in formula (7):

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

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, when dominated formulate (8)Shown in electric capacity brachium pontis absorb power p_cEqual twice ripple power p of system shown in formula (5)_rTime, twice ripple merit of systemRate is absorbed by electric capacity brachium pontis completely.

Illustrate the working method of this circuit below: make power-factor angleBe that circuit working is in unit power factor rectifierState, equates with formula (5) according to formula (8), obtains θ=-π/4+k π, and k is integer. Make θ=-π/4, DC sideVoltage v_dc=450V, the capacitance fluctuations peak value V in formula (6)_c=190V, can draw two capacitance voltage ripples according to formula (6)Moving equation is 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,Be equal to capacitor C₂Voltage, 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, DPoint 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 of a 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 circuit of the present invention can reach 300V. And shown in Fig. 3In circuit, 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 invention is than circuit shown in Fig. 3, and it is straightStream voltage utilization has improved approximately one times, thereby the present invention has wider range of application, and has higher efficiency.

By reference to the accompanying drawings the specific embodiment of the present invention is described although above-mentioned, not the limit to protection domain of the present inventionSystem, one of ordinary skill in the art should be understood that on the basis of technical scheme of the present invention, those skilled in the art do not need to payGo out various amendments that creative work can make or distortion still in protection scope of the present invention.

Claims (2)

1. Single-phase PWM Rectifier is eliminated a secondary ripple circuit, it is characterized in that: comprise AC, converter and straightStream side, described AC is connected with converter by inductance, and the opposite side of converter is connected with DC side, at AC inputBe connected with capacitor C with DC side negative pole end₂, be connected with capacitor C at AC input and DC side positive terminal₁；

Described AC is divided into the first interchange end and exchanges end with second, and described converter comprises A phase brachium pontis in parallel, B phase brachium pontisWith electric capacity brachium pontis, first exchanges end is connected with the A phase brachium pontis of converter by inductance L 2, and second exchanges end connects with electric capacity brachium pontisConnect, 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, and B phase brachium pontis is by switching tube S3 and the switch of connectingPipe S4 composition, 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 withInductance L 2 connects, and the tie point of switching tube S3 and switching tube S4 is connected with inductance L 1, the tie point of capacitor C 1 and capacitor C 2The tie point that exchanges end with inductance L 1 with second is connected.

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