CN101154816A - Parallel power supply system and method for acquiring nonuniform fluid - Google Patents

Abstract

The invention discloses a method of acquiring uneven fluidity of parallel power system, which includes that the following steps that: current is sampled from the parallel power system to acquire the actual output current of each stand-aloe of in the parallel power system and actual output whole load current of the parallel power system; the uneven fluidity of each stand-alone is got according to the actual output current of each stand-alone and the whole load current; the uneven fluidity of the parallel power system is got by averaging the uneven fluidity of each stand-alone and output. The uneven fluidity of the parallel power system acquired with the method reflects the physical meaning of the uneven fluidity better and provides an evaluating standard for evaluating the system performance of the parallel power system. The invention discloses a parallel power system at the same time.

Description

The method of a kind of parallel power supply system and acquisition nonuniform fluid

Technical field

The present invention relates to power technique fields, relate in particular to a kind of method and device thereof that in parallel power supply system, obtains nonuniform fluid.

Background technology

Adopt uninterrupted power supply (UPS, Uninterruptable Power Source) parallel technology can improve the extendible capacity and the redundant reliability of UPS electric power system.Through research and practice in recent years, the parallel technology of UPS has been obtained significant progress and plentiful and substantial application achievements.But present UPS parallel technology much all is confined to adopt the unit of a plurality of same capability grades to carry out parallel connection, carries out system in parallel based on the different capacitance grade unit and is in the starting stage.Wherein, be used to weigh a nonuniform fluid that important indicator is exactly a parallel power supply system of UPS parallel power supply system performance.

In the prior art, the method that obtains the nonuniform fluid of parallel power supply system is the nonuniform fluid that obtains each unit of this parallel power supply system of composition, then with the nonuniform fluid of the maximum in the nonuniform fluid of each unit as parallel power supply system.When the parallel power supply system that adopts this method that the unit of same capability grade is formed is evaluated and tested, because it is all identical that each single-machine capacity accounts for the weight of parallel power supply system rated capacity, the nonuniform fluid of parallel power supply system can objectively reflect the performance of this parallel power supply system.

Each single-machine capacity grade in parallel power supply system is not simultaneously, obtain the nonuniform fluid of parallel power supply system according to aforesaid way, because the nonuniform fluid of low capacity type will be worse than the nonuniform fluid of big capacity type under the identical condition of performance, get maximum as the apparent reasonability of losing of the nonuniform fluid of system.For example: adopt the system of two machine parallel connections, wherein the capacity of a unit is 3 times of another unit, and for these two units, under any circumstance always direction is opposite for their circulation, and size is identical; The output-current rating of large capacity single machine then is 3 times of low capacity unit output-current rating, then the nonuniform fluid of low capacity type is 3 times of big capacity type nonuniform fluid, get the nonuniform fluid of the nonuniform fluid of each unit maximum as parallel power supply system, then the nonuniform fluid of the parallel power supply system that obtains according to this mode may not meet the demands, for need making the low capacity type, the nonuniform fluid that reduces parallel power supply system reaches the requirement of the nonuniform fluid index identical with big capacity type, and very harsh and unreasonable for the low capacity type.Simultaneously, the physical significance of the nonuniform fluid of parallel power supply system is the power system capacity percentage that self circulation of parallel power supply system is consumed, the physical significance of the inreal reflection nonuniform fluid of the nonuniform fluid index of the parallel system that the method for employing prior art obtains index.

Summary of the invention

The invention provides the method for a kind of parallel power supply system and acquisition nonuniform fluid,, make and parallel power supply system is carried out objective evaluating according to this nonuniform fluid in order to the nonuniform fluid of parallel power supply system to be provided.

The invention provides following technical scheme:

A kind of method that obtains the parallel power supply system nonuniform fluid comprises the steps:

Each output current of sampling obtains the actual output current of each unit in this system and the load total current of the actual output of this parallel power supply system in parallel power supply system;

The nonuniform fluid that obtains each unit according to the actual output current and the described load total current of each unit;

The nonuniform fluid of each unit is averaged the nonuniform fluid that obtains described parallel power supply system and exports this nonuniform fluid.

Preferable, the actual output current of each unit of sampling respectively, and obtain the load total current of the actual output of parallel power supply system according to the actual output current of each unit.

Perhaps, sample the respectively actual output current of unit and the load total current of the actual output of described parallel power supply system.

Preferable, determine that the nonuniform fluid of each unit comprises step:

Obtain the load current that each unit be should bear respectively according to the specified total capacity of described load total current, parallel power supply system and the rated capacity of unit;

Calculate the difference between the actual output current of each unit and the load current that this unit be should bear, and with the ratio of the effective value of this difference and this unit output-current rating effective value nonuniform fluid as this unit.

Preferable, the weight that accounts for the specified total capacity of described parallel power supply system according to each unit rated capacity is weighted on average the nonuniform fluid of each unit.

Perhaps, the nonuniform fluid to each unit carries out arithmetic average.

The paralleling model of described parallel power supply system is redundant fashion or is dilatation way.

A kind of nonuniform fluid measurement mechanism comprises:

Sampling unit, each output current of the parallel power supply system that is used for sampling, and the sampled value of exporting described electric current;

Processing unit, be used for receiving the sampled value of each electric current of described parallel power supply system, obtain the actual output current of each unit in this system and the load total current of the actual output of this system, and obtain the nonuniform fluid of each unit and the nonuniform fluid that the nonuniform fluid of each unit is averaged the described parallel power supply system of acquisition according to the load total current of the actual output current of each unit and the actual output of this system;

Output unit is used to export the nonuniform fluid of described parallel power supply system.

Preferable, sample the respectively actual output current of each unit of described sampling unit;

Described processing unit receives the sampled value of the actual output current of each unit in the described parallel power supply system, and obtains the load total current of the actual output of parallel power supply system according to the actual output current of each unit.

Perhaps, sample the respectively actual output current of unit and the load total current of the actual output of described parallel power supply system of described sampling unit.

Described processing unit accounts for the specified total capacity of described parallel power supply system according to each unit rated capacity weight is weighted on average the nonuniform fluid of each unit.

Perhaps, described processing unit carries out arithmetic average to the nonuniform fluid of each unit.

A kind of parallel power supply system comprises:

A plurality of ups powers, this ups power is connected in parallel, and is used for providing power supply to load;

The nonuniform fluid measurement mechanism, each output current of ups power system is used for sampling, obtain the actual output current of each ups power in this system and the load total current of the actual output of this system, and the nonuniform fluid that obtains each unit according to the actual output current and the described load total current of each unit, and the nonuniform fluid of each unit averaged the nonuniform fluid that obtains described parallel power supply system and export this nonuniform fluid.

Preferable, the nonuniform fluid measurement mechanism in the described parallel power supply system comprises:

Sampling unit, each output current of the described parallel power supply system that is used for sampling, and the sampled value of exporting described electric current.

Processing unit, be used for receiving the sampled value of each electric current of described parallel power supply system, obtain the actual output current of each unit in this system and the load total current of the actual output of this system, and obtain the nonuniform fluid of each unit and the nonuniform fluid that the nonuniform fluid of each unit is averaged the described parallel power supply system of acquisition according to the load total current of the actual output current of each unit and the actual output of this system;

Output unit is used to export the nonuniform fluid of described parallel power supply system.

Beneficial effect of the present invention is as follows:

The nonuniform fluid of the parallel power supply system that employing the present invention obtains has reflected the power system capacity percentage that circulation consumed of parallel power supply system self, the physical significance that not only meets this index, this index also can rationally reflect the performance in parallel of parallel power supply system simultaneously, for evaluation and test parallel power supply system performance provides standard.

Description of drawings

Fig. 1 is the system configuration schematic diagram in the embodiment of the invention;

Fig. 2 is the nonuniform fluid measurement mechanism structural representation in the embodiment of the invention;

Fig. 3 is the process chart in the embodiment of the invention;

Fig. 4 is the structural representation of parallel power supply system in the embodiment of the invention.

Embodiment

Present embodiment obtains the actual output current of each unit and the load total current of the actual output of this parallel power supply system by each output current in the sampling parallel power supply system, and obtaining the nonuniform fluid of each unit, the nonuniform fluid with each unit averages the nonuniform fluid that obtains described parallel power supply system then.It is the weight calculation weighted average that accounts for the specified total capacity of parallel power supply system according to each unit rated capacity that the nonuniform fluid of each unit is averaged.

Consult Fig. 1, the parallel power supply system in the present embodiment comprises: a plurality of ups powers 110 and nonuniform fluid measurement mechanism 120.Each ups power 110 power supply is connected in parallel, and is used for providing power supply to load; Nonuniform fluid measurement mechanism 120 be used for sampling each output current of ups power system, obtain the actual output current of each ups power in this system and the load total current of the actual output of this system, and the nonuniform fluid that obtains each unit according to the actual output current and the described load total current of each unit, and the nonuniform fluid of each unit averaged the nonuniform fluid that obtains described parallel power supply system and export this nonuniform fluid.

Consult Fig. 2, nonuniform fluid measurement mechanism 120 comprises: sampling unit 1201, processing unit 1202 and output unit 1203.Sampling unit 1201 be used for sampling each output current of parallel power supply system and the sampled value of exporting described electric current; Processing unit 1202 is used to receive the sampled value of each electric current, obtain the actual output current of each unit in the parallel power supply system and the load total current of the actual output of this system according to sampled value, and obtain the nonuniform fluid of each unit and the nonuniform fluid that the nonuniform fluid of each unit is averaged the described parallel power supply system of acquisition according to the load total current of the actual output current of each unit and the actual output of this system; Output unit 1203 is used to export the nonuniform fluid of described parallel power supply system.

According to practical application, each unit in this parallel power supply system can be the same capability grade, also can be different capacitance grade; The paralleling model of parallel power supply system can be redundant fashion, also can be dilatation way.

Below unit by different capacitance grade carry out power-supply system in parallel and describe.

Consult shown in Figure 3ly, the processing procedure of nonuniform fluid that obtains parallel power supply system is as follows:

Each output current in step 301, the sampling parallel power supply system obtains the actual output current of each unit in this system and the load total current of the actual output of this parallel power supply system.

When each output current in the parallel power supply system is sampled, can sample the respectively actual output current of each unit, obtain the actual output current of each unit, then with the algebraical sum of the actual output current of each unit load total current as the actual output of parallel power supply system; Perhaps, when each output current in the parallel power supply system is sampled, the load total current of the actual output current of the unit of sampling respectively and the actual output of this parallel power supply system.

Step 302, obtain the load current that each unit be should bear respectively according to the rated capacity of described load total current, parallel power supply system and the rated capacity of unit.

Step 303, calculate the difference between the actual output current of unit and the load current that this unit be should bear, and with the ratio of the effective value of this difference and this unit output-current rating effective value nonuniform fluid as this unit.

Step 304, the weight that accounts for the specified total capacity of this parallel power supply system according to each unit rated capacity average the nonuniform fluid that obtains parallel power supply system with the nonuniform fluid of each unit.

The nonuniform fluid of step 305, output-parallel power-supply system.

Below further above-mentioned processing procedure is described.

Consult parallel power supply system shown in Figure 4, after parallel power supply system is sampled, obtain the actual output current I of each unit _iLoad total current I with the actual output of this parallel power supply system ₀, then according to (1) formula

${\∂}_i=\frac{|I_i-I_0\×\frac{C_i}{C_{\mathrm{total}}}|}{I_{\mathrm{ir}}}\×100\%---\left(1\right)$

Calculate the nonuniform fluid of each unit; (1) in the formula _ _iBe the nonuniform fluid of unit, I _iBe unit actual output current, I ₀Be the load total current of the actual output of system, I _IrBe unit output-current rating, C _iBe unit rated capacity, C _TotalBe the specified total capacity of system.

After obtaining the nonuniform fluid of each unit, according to (2) formula

$\mathrm{\δ}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{K}_i*{\∂}_i---\left(2\right)$

Calculate the nonuniform fluid of parallel power supply system; (2) δ is the nonuniform fluid of parallel power supply system in the formula, K _iBe the weight that i unit rated capacity accounts for the specified total capacity of system, K _iCan obtain by (3) formula:

$K_i=\frac{C_i}{C_{\mathrm{total}}}=\frac{I_{\mathrm{ir}}}{I_{\mathrm{total}}}---\left(3\right)$

(3) I _IrBe unit output-current rating, I _TotalBe the specified total output current of system, C _iBe unit rated capacity, C _TotalBe the specified total capacity of system.

In the above-mentioned processing, the weight that accounts for the specified total capacity of parallel power supply system according to each unit rated capacity averages the nonuniform fluid of acquisition parallel power supply system to the nonuniform fluid of each unit, this nonuniform fluid index has showed the specified total capacity percentage of system that self circulation of parallel power supply system is consumed, and has really reflected the physical significance of nonuniform fluid.

Below prove the physical significance of the nonuniform fluid that this case method obtains by derivation.

Adopt UPS parallel power supply system shown in Figure 4, for convenience of description, further be defined as follows:

C _i--the rated capacity of i unit;

I _Ir--the output-current rating of i unit;

I _i--the actual output current of i unit;

I _Icir--the circulation of i unit;

K _i--the ratio of i the specified total capacity of unit rated capacity and system;

_ _i--the nonuniform fluid of i unit;

C _Total--the specified total capacity of parallel power supply system;

I _Total--the specified total output current of parallel power supply system;

I _o--parallel power supply system load total current,

δ--parallel power supply system nonuniform fluid.

Each electric current homophase directly is converted into scalar operation with vector calculus in the supposing the system.Equivalent electric circuit by parallel power supply system has:

$I_{\mathrm{total}}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{I}_{\mathrm{ir}}---\left(4\right)$

$C_{\mathrm{total}}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{C}_i---\left(5\right)$

$K_i=\frac{C_i}{C_{\mathrm{total}}}=\frac{I_{\mathrm{ir}}}{I_{\mathrm{total}}}---\left(6\right)$

$I_o=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{I}_i---\left(7\right)$

I _icir＝I _i-K _i*I ₀ (8)

Association type (4), (5), (6), (7) and (8):

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{I}_{\mathrm{icir}}\≡0---\left(9\right)$

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{K}_i\≡1---\left(10\right)$

According to the definition of IEC standard to nonuniform fluid, the nonuniform fluid of each unit is expressed as in the parallel power supply system:

${\∂}_i=\frac{\left|I_{\mathrm{icir}}\right|}{I_{\mathrm{ir}}}\×100\%---\left(11\right)$

According to the method that obtains the parallel power supply system nonuniform fluid, the nonuniform fluid that obtains the parallel connection of UPS with different capacitance grade power-supply system is as follows:

$\mathrm{\δ}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{K}_i*{\∂}_i=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{I_{\mathrm{ir}}}{I_{\mathrm{total}}}*\frac{\left|I_{\mathrm{icir}}\right|}{I_{\mathrm{ir}}}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\left|I_{\mathrm{icir}}\right|}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{I}_{\mathrm{ir}}}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\left|I_{\mathrm{icir}}\right|}{I_{\mathrm{total}}}---\left(12\right)$

From the derivation of (12) formula as can be seen, parallel connection of UPS with different capacitance grade power-supply system nonuniform fluid δ has characterized physically that each unit circulation is to the consumption degree of the specified total capacity of system in the parallel power supply system, and this physical meaning with parallel power supply system nonuniform fluid index is consistent.

In addition, from (12) formula also as can be seen, the parallel power supply system nonuniform fluid is the weighted sum (flexible strategy are the ratio of the specified total capacity of each unit rated capacity and system) of each unit nonuniform fluid in the system, and this has characterized the parallel power supply system nonuniform fluid on mathematics be the weighted average of all unit nonuniform fluids in the system.Further specify the mathematical meaning of parallel power supply system nonuniform fluid below.

Suppose in the parallel power supply system maximum unit nonuniform fluid for _ _Max, flexible strategy are K _Max, minimum unit nonuniform fluid is _ _Min, flexible strategy are K _MinThen:

$\mathrm{\δ}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{K}_i*{\∂}_i=K_{\max }*{\∂}_{\max }+\underset{i=2}{\overset{n}{\mathrm{\Σ}}}{K}_i*{\∂}_i$

Because $\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{K}_i=1,$

Then:

$\mathrm{\δ}=(1-\underset{i=2}{\overset{n}{\mathrm{\Σ}}}{K}_i)*{\∂}_{\max }+\underset{i=2}{\overset{n}{\mathrm{\Σ}}}{K}_i*{\∂}_i={\∂}_{\max }+\underset{i=2}{\overset{n}{\mathrm{\Σ}}}{K}_i*({\∂}_i-{\∂}_{\max })$

Because _ _i-_ _Max＜0,

So:

$\mathrm{\&delta;}={\&PartialD;}_{\max }+\underset{i=2}{\overset{n}{\mathrm{\&Sigma;}}}{K}_i*({\&PartialD;}_i-{\&PartialD;}_{\max })<{\&PartialD;}_{\max }$

As a same reason, can obtain:

$\mathrm{\&delta;}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{K}_i*{\&PartialD;}_i=K_{\min }*{\&PartialD;}_{\min }+\underset{i=2}{\overset{n}{\mathrm{\&Sigma;}}}{K}_i*{\&PartialD;}_i={\&PartialD;}_{\min }+\underset{i=2}{\overset{n}{\mathrm{\&Sigma;}}}{K}_i*({\&PartialD;}_i-{\&PartialD;}_{\min })>{\&PartialD;}_{\min }$

So obtain: _ _Min＜δ＜_ _Max

As can be seen from the above analysis, the nonuniform fluid of the parallel power supply system that obtains in the present embodiment has embodied the mathematical meaning of nonuniform fluid.

Adopt the method for present embodiment to carry out actual measurement, the measurement result of acquisition is as follows:

In the experiment of the different capacitance grade three unit parallel power supply system model machines of three-phase 208V output system 30KVA, 15KVA and 5KVA, concrete nonuniform fluid data are shown in following each table.

Table 1 is the unloaded circulation data of parallel power supply system; Table 2 is the test data of the resistive full load of parallel power supply system; Table 3 is the test data of parallel power supply system rectification full load.

Table 1

Table 2,

5KVA(10KVA)

3.15％

1.89％

Table 3

From above-mentioned test result as can be seen, the nonuniform fluid of the parallel power supply system that the method in the employing present embodiment obtains has reflected the physical meaning of parallel power supply system nonuniform fluid to have the meaning of better guidance and actual reference preferably; When this method is applied to the measurement of same capability grade UPS parallel power supply system nonuniform fluid simultaneously, can directly (1) formula of calculating each unit nonuniform fluid be converted into:

${\&PartialD;}_i=\frac{|I_i-I_0\&times;\frac{1}{N}|}{I_{\mathrm{ir}}}\&times;100\%$

Obtain the nonuniform fluid of each unit in the parallel power supply system according to following formula after, obtain the nonuniform fluid of the parallel power supply system that the unit of same capability grade forms by the arithmetic average of calculating each unit nonuniform fluid.

Present embodiment is that example describes the present invention with the UPS parallel power supply system, but the present invention not only is confined to this, is equally applicable to parallel power supply systems such as direct current output-parallel power-supply system, frequency converter, and its method roughly the same repeats no more.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (14)

1. a method that obtains the parallel power supply system nonuniform fluid is characterized in that, comprises the steps:

Sample rate current in parallel power supply system obtains the actual output current of each unit in this system and the load total current of the actual output of this parallel power supply system;

The nonuniform fluid that obtains each unit according to the actual output current and the described load total current of each unit;

The nonuniform fluid of each unit is averaged the nonuniform fluid that obtains described parallel power supply system and exports this nonuniform fluid.

2. the method for claim 1 is characterized in that, the actual output current of each unit of sampling respectively, and obtain the load total current of the actual output of parallel power supply system according to the actual output current of each unit.

3. the method for claim 1 is characterized in that, the load total current of the actual output current of the unit of sampling respectively and the actual output of described parallel power supply system.

4. as claim 1,2 or 3 described methods, it is characterized in that, determine that the nonuniform fluid of each unit comprises step:

Obtain the load current that each unit be should bear respectively according to the specified total capacity of described load total current, parallel power supply system and the rated capacity of unit;

Calculate the difference between the actual output current of unit and the load current that this unit be should bear, and with the ratio of the effective value of this difference and this unit output-current rating effective value nonuniform fluid as this unit.

5. method as claimed in claim 4 is characterized in that, the nonuniform fluid of each unit is carried out arithmetic average.

6. method as claimed in claim 4 is characterized in that, the weight that accounts for the specified total capacity of described parallel power supply system according to each unit rated capacity is weighted on average the nonuniform fluid of each unit.

7. method as claimed in claim 4 is characterized in that, the paralleling model of described parallel power supply system is redundant fashion or is dilatation way.

8. a nonuniform fluid measurement mechanism is characterized in that, comprising:

Sampling unit, each output current of the parallel power supply system that is used for sampling, and the sampled value of exporting described electric current;

Processing unit, be used for receiving the sampled value of each output current of described parallel power supply system, obtain the actual output current of each unit in this system and the load total current of the actual output of this system, and obtain the nonuniform fluid of each unit and the nonuniform fluid that the nonuniform fluid of each unit is averaged the described parallel power supply system of acquisition according to the load total current of the actual output current of each unit and the actual output of this system;

Output unit is used to export the nonuniform fluid of described parallel power supply system.

9. device as claimed in claim 8 is characterized in that, sample the respectively actual output current of each unit of described sampling unit;

Described processing unit receives the sampled value of the actual output current of each unit in the described parallel power supply system, and obtains the load total current of the actual output of parallel power supply system according to the actual output current of each unit.

10. device as claimed in claim 8 is characterized in that, described sampling unit sample the respectively actual output current of unit and the load total current of the actual output of described parallel power supply system.

11., it is characterized in that described processing unit carries out arithmetic average to the nonuniform fluid of each unit as each described device of claim 8 to 10.

12., it is characterized in that described processing unit accounts for the specified total capacity of described parallel power supply system according to each unit rated capacity weight is weighted on average the nonuniform fluid of each unit as each described device of claim 8 to 10.

13. a parallel power supply system is characterized in that, comprising:

A plurality of ups powers, this ups power is connected in parallel, and is used for providing power supply to load;

The nonuniform fluid measurement mechanism, the electric current of ups power system is used for sampling, obtain the actual output current of each ups power in this system and the load total current of the actual output of this system, and the nonuniform fluid that obtains each unit according to the actual output current and the described load total current of each unit, and the nonuniform fluid of each unit averaged the nonuniform fluid that obtains described parallel power supply system and export this nonuniform fluid.

14. system as claimed in claim 13 is characterized in that, described nonuniform fluid measurement mechanism comprises:

Sampling unit, each output current of the described parallel power supply system that is used for sampling, and the sampled value of exporting described electric current;

Processing unit, be used for receiving the sampled value of each output current of described parallel power supply system, obtain the actual output current of each unit in this system and the load total current of the actual output of this system, and obtain the nonuniform fluid of each unit and the nonuniform fluid that the nonuniform fluid of each unit is averaged the described parallel power supply system of acquisition according to the load total current of the actual output current of each unit and the actual output of this system;

Output unit is used to export the nonuniform fluid of described parallel power supply system.

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