CN104218835B - The circular current control method of parallel power converting means and device - Google Patents

Abstract

The invention discloses the circular current control method of a kind of parallel power converting means, this control method includes: step 1: selected reference carrier signal generator and carrier signal generator to be adjusted；Step 2: calculate the spill current in k moment；Step 3: calculate the spill current size in k moment according to the spill current in k moment；Step 4: utilize phase-shift phase that k moment carrier signal phase is adjusted；Step 5: calculate the spill current in k+g moment；Step 6: calculate the spill current size in k+g moment according to the spill current in k+g moment₂；Step 7: determine that phase place adjusts the situation of change of pre-post difference size of current；Step 8: adjust the carrier signal phase in k+g moment according to the situation of change of spill current size.The present invention can effectively and reliably suppress the circulation caused in parallel power transformation system because of the phase contrast between the PWM carrier signal of each power converter.The present invention discloses a kind of control device for parallel power converting means.

Description

The circular current control method of parallel power converting means and device

Technical field

The present invention relates to power-converting device control field, particularly relate to a kind of be made up of also multiple power converters Connection power converter device ring method of flow control.The invention still further relates to a kind of control device for parallel power converting means.

Background technology

Power-converting device parallel technology is expansion power-converting device power, improves reliability, realizes power converter dress Put the important technical that power is adjusted flexibly.Circulation is the problem that parallel power converting means must solve, and this makes circulation Control technology becomes key and the core of power-converting device parallel technology.Chinese invention patent CN200810166314.3 (Shen Please day: 2008.09.19) propose to utilize the positive and negative busbar voltage difference of the inverter constituting many power-converting devices and circulation detection Circulation is controlled by value sum.Chinese invention patent CN201110275998.2 (applying date: 2011.09.08) proposes logical Cross and respectively produce a residual voltage at three-phase and be injected into this phase voltage command, the thereby correction to this phase voltage command, thus Realize the control to circulation.Chinese invention patent CN200710121110.3 (applying date: 2007.08.30) proposes by controlling In SVM, proportionate relationship between action time and the action time of nnn of zero vector ppp regulates the action time of zero vector, Thus reach the purpose of the zero sequence circulation between back-to-back converter.Document 1 (Analysis of parallel operation methods of PWM inverters sets for an ultra-high speed elevator,IEEE,2000, P944-950) propose a kind of based on the circular current control method controlled with spill current.Document 2 (uses the parallel connection of reference voltage regulation Adverser control technology, Electric Machines and Control, 2011 (2): P84-88) the voltage compensation letter exported by circulation controller is proposed Number the torque voltage signal of motor current controller output is compensated thus realizes loop current suppression.Document 3 (Distributed Control for AC Motor Drive Inverters in Parallel Operation,IEEE Tran.I.E., 2011:58 (12), 5361-5370) propose to utilize line synchro to realize modulating wave by synchronous control mode Synchronize, asynchronous between eliminating because of each inverter output voltage with this.

Research shows, constitutes the phase place between the carrier signal in each power converter PWM of parallel power convertor device Difference situation has material impact to the circulation in parallel power convertor device: the phase contrast between carrier signal is the biggest, and circulation is also The biggest.For the circulation in the parallel power convertor device that caused by the phase contrast of intercarrier, above-mentioned prior art or It is not directed to, though or relate to, but its regulating object is modulating wave rather than carrier signal (such as document 3), therefore cannot utilize State prior art eliminate by carrier signal between the parallel power convertor device that caused of phase contrast in circulation.For this One problem, can utilize in engineering practice use based on same clock signal carry out each power converter PWM or Eliminate the phase contrast between carrier signal by bus mode, communication modes etc., and then eliminate by the phase contrast between carrier signal Circulation in the parallel power convertor device caused.But when parallel power changer in parallel power convertor device When quantity is too much, cannot be able to tackle because of the PWM port resource limit of controller based on same clock signal method；Bus side Formula, communication modes etc. need to set up line synchro (synchronization line), communication line etc., and when line synchro, communication Circuit is easily caused phase difference variable between carrier signal after receiving interference big, and then causes bigger circulation to occur.Even if it is additionally, logical After crossing the phase contrast eliminating between carrier signal based on same clock signal method or the method such as bus mode, communication modes, raw The pwm switching signal become still may be because of drive amplification circuit before delivering to power model through the drive amplification of drive amplification circuit The nuance of self or external interference etc. and to cause pwm switching signal to produce before and after drive amplification inconsistent, thus cause There is bigger circulation in parallel power convertor device person.

Therefore, the most reliably and do not limited by the quantity of parallel power changer in connection power converter device and effectively pressed down The circulation caused because of the phase contrast between the PWM carrier signal of each power converter in parallel power changer system processed just becomes One of power-converting device parallel technology has important technological problems to be solved.

Summary of the invention

The technical problem to be solved in the present invention is to propose the circular current control method of a kind of parallel power converting means, the method Can effectively and reliably suppress in parallel power changer system because of the phase contrast between the PWM carrier signal of each power converter And the circulation caused, and not by connection power converter device, the quantity of parallel power changer is limited, loop current suppression realizes Convenient.

For solving above-mentioned technical problem, the technology solution party of the circular current control method of the parallel power converting means of the present invention Case is, comprises the steps:

Step 1: selected reference carrier signal generator and carrier signal generator to be adjusted；

Step 2: calculate the spill current in k moment；

Step 3: calculate the spill current size in k moment according to the spill current in k moment；

Step 4: utilize phase-shift phase that k moment carrier signal phase is adjusted；

Step 5: calculate the spill current in k+g moment, wherein g >=1；

Step 6: calculate the spill current size in k+g moment according to the spill current in k+g moment₂, wherein g >=1；

Step 7: determine that phase place adjusts the situation of change of pre-post difference size of current；

Step 8: adjust the carrier signal phase in k+g moment, wherein g >=1 according to the situation of change of spill current size.

In described step 3 and step 6, calculating for spill current size is to be with spill current by being expressed as by spill current The monotonic increasing function of independent variable realizes.

Carrier signal phase is adjusted by described step 8 according to following arbitrary rule:

Rule 1: if f₁>f₂, i.e. Δ f < 0, then keep Ph (k+g) currency constant, otherwise Ph (k+g) ← Ph (k), Δ Ph ←-Δ Ph；

Rule 2: if f₁>f₂, i.e. Δ f < 0, then keep Ph (k+g) currency constant, otherwise Ph (k+g) ← Ph (k)-Δ Ph；

Rule 3: if Δ f≤α, keep Ph (k+g) currency constant, if α < Δ f < β, Ph (k+g) ← Ph (k), if β≤Δ F, then Ph (k+g) ← Ph (k)-Δ Ph；

Wherein f₁For the spill current size in k moment in step 3；

f₂For the spill current size in k+g moment in step 6；

Spill current size variation amount Δ f=f₂-f₁；

Ph (k) is the carrier signal phase in k moment；

Ph (k+g) is the carrier signal phase in k+g moment；

Δ Ph is phase-shift phase；

← for assignment operator；

α, β are respectively preset value, and α < β.

Described phase-shift phase Δ Ph meets following condition:

0<ΔPh≤0.5×T_car×ω_e

Wherein T_carIt is the cycle of described carrier wave, ω_eIt is electrical angle speed.

Described phase-shift phase Δ Ph is a steady state value preset；Or,

Described phase-shift phase Δ Ph be one with spill current big small function f or spill current size variation amount Δ f the letter as independent variable Number；Phase-shift phase Δ Ph calculates according to following arbitrary formula:

ΔPh=ζ×f×ΔPh₀；

ΔPh=ζ×Δf×ΔPh₀；

ΔPh=ζ×f×ΔPh₀+δ×Δf×ΔPh₀

In formula, benchmark phase-shift phase Δ Ph₀Being steady state value set in advance, ζ and δ is constant.

Described circular current control method is persistently carried out for the adjustment of carrier phase；Or

Perform s time when exceeding threshold value set in advance according to some cycles or the size of current function f that is on duty, wherein s >=1； Or

Continuously perform until spill current big small function f stops less than after threshold value set in advance again.

The present invention also provides for a kind of control device for parallel power converting means, and described control device includes:

Current controller；Current controller enters according to the current feedback values of current instruction value and each parallel power converting means Row controls, and exports modulated signal；

Carrier signal generator；Carrier signal generator generates the carrier signal needed for PWM unit；

PWM unit；Modulated signal that PWM unit exports according to current controller and the carrier wave that carrier signal generator generates Signal carries out pulsewidth modulation, and output is for controlling the switching signal of power model；

Wherein, also include:

Spill current computer；Spill current computer calculates difference electricity according to the current feedback values of each parallel power converting means Stream；

Spill current size counter；It is poor that spill current size counter calculates according to the result of calculation of described spill current computer The size of electric current；

Phase regulator；The spill current size that phase regulator exports according to spill current size counter, utilizes aforesaid The carrier signal phase that carrier signal generator to be adjusted is generated by method is adjusted.

Or, described control device includes:

Current controller；Current controller enters according to the current feedback values of current instruction value and each parallel power converting means Row controls, and output controls voltage moment components；

Calculation of circulating current device；Calculation of circulating current device calculates circulation value according to the current feedback values of each parallel power converting means；

Circulation controller；The circulation value that circulation controller exports according to circulation command value and described calculation of circulating current device is controlled System, output controls voltage loop current suppression component；

Carrier signal generator；Carrier signal generator generates the carrier signal needed for PWM unit；

Modulated signal maker；The control voltage moment components that modulated signal maker exports according to described current controller And the control voltage loop current suppression component of described circulation controller output generates modulated signal；

PWM unit；Modulated signal and carrier signal generator that PWM unit exports according to described modulated signal maker are raw The carrier signal become carries out pulsewidth modulation, and output is for controlling the switching signal of power model；

Wherein, also include:

Spill current computer；Spill current computer calculates difference electricity according to the current feedback values of each parallel power converting means Stream；

Spill current size counter；It is poor that spill current size counter calculates according to the result of calculation of described spill current computer The size of electric current；

Phase regulator；The spill current size that phase regulator exports according to spill current size counter, utilizes aforesaid The carrier signal phase that carrier signal generator to be adjusted is generated by method is adjusted.

In the circular current control method of the parallel power converting means of the present invention and engineering practice based on same clock signal, The difference of the method such as bus mode, communication modes (follow-up referred to as engineering method) is:

The fully utilized software algorithm of a, the inventive method can be implemented, it is impossible to increases additional hardware resources, engineering method Implement then to depend on line synchro, communication line etc.；

B, the present invention are directly to suppress parallel power converting means by the phase place adjusting parallel connection converter carrier signal The circulation of person, engineering method be then by eliminating by carrier signal based on same clock signal, line synchro, communication line etc. between Phase contrast indirectly suppress the circulation of parallel power converting means person (therefore cannot tackle pwm switching signal at drive amplification Front and back produce this situation inconsistent)；

The closed-loop fashion that the suppression of c, the inventive method circulation for being caused by the phase contrast between carrier signal uses, And engineering method uses open loop approach for the elimination of phase contrast between carrier signal, for by the phase contrast between carrier signal The suppression of the circulation caused is open loop approach equally, it is clear that the closed-loop fashion of the present invention is better than the open loop side of engineering method Formula.

What the present invention can reach has the beneficial effect that

A, without be completely dependent in the case of increasing additional hardware resources software control can effectively suppress to be believed by carrier wave Phase contrast between number suppresses the circulation of parallel power converting means person indirectly；

B, can have reply pwm switching signal before and after drive amplification, produce this special applications of circulation that is inconsistent and that cause Occasion；

C, directly judge that phase place regulates whether suitably with loop current suppression effect, therefore loop current suppression effect the most direct, Rapidly, accurately.

Accompanying drawing explanation

The present invention is described in further detail with detailed description of the invention below in conjunction with the accompanying drawings:

Fig. 1 is that the parallel power transformation system of the circular current control method of the parallel power converting means applying the present invention should A kind of structural representation for electric machine speed regulation；

Fig. 2 is the parallel power transformation system application of the circular current control method applying parallel power converting means of the present invention Another kind of structural representation in electric machine speed regulation.

Detailed description of the invention

The application parallel power transformation system of the circular current control method of the parallel power converting means of the present invention Including control device two parts of parallel power converting means and parallel power converting means, wherein parallel power converting means by Two power converters being connected in parallel and corresponding reactor composition, power converter here can be biphase, three-phase very To being more heterogeneous inverter or PWM rectifier, the correspondence of the AC of power converter is after concatenating corresponding reactor It is connected, is then connected to load or power supply (electrical network or TRT) afterwards；All anodes of power converter DC side are with all Negative terminal is connected with common DC source or Equivalent DC power supply (such as the DC side of diode rectifier) after being respectively connected with again, or Person's power converter DC side is connected with the most independent DC source (or Equivalent DC power supply) respectively, or some electrical power becomes The DC side anode of parallel operation and negative terminal be respectively connected with after again with common DC source or Equivalent DC power supply (such as diode rectification The DC side of device) be connected, the DC side of remaining power converter respectively with the most independent DC source (or Equivalent DC electricity Source) it is connected；The control device of parallel power converting means includes current-order generator, current controller, PWM unit, carrier wave Signal generator etc..

Next circulation to the parallel power converting means of the present invention as a example by the parallel power converting means shown in Fig. 1 Control method and the control device for parallel power converting means illustrate.It is pointed out that the electricity in parallel of the present invention The certain types of parallel power conversion dress that the application of the circular current control method of force conversion system is not limited in Fig. 1 Put, and the power converter constituting parallel power converting means is 2.

For simplifying follow-up narration, with 2 inversions powered by same DC source as shown in Figure 1 in subsequent embodiment Device constitutes, with parallel power converting means that motor is load for the application ring to the parallel power converting means of the present invention Method of flow control illustrates.

Embodiment 1

As it is shown in figure 1, parallel power transformation system includes parallel power converting means and the control of parallel power converting means Device two parts processed, wherein parallel power converting means farther include the 1# inverter that is connected in parallel and 2# inverter, 1 straight Stream power supply, 1# amperometric and 2# amperometric；Each inverter is respectively by the control device of parallel power converting means It is controlled；The control device of parallel power converting means farther includes current-order generator (herein for speed controlling Device), current controller, calculation of circulating current device, circulation controller, modulated signal maker and PWM unit, carrier signal occur Device；The identical polar end of 1# inverter and the DC side of 2# inverter is connected with DC source after connecting again, 1# inverter and The corresponding reactor L in warp each concatenation of the AC of 2# inverter₁、L₂The most connected to each other, it is connected to afterwards Its common load (in the present embodiment, common load is a motor)；The control device of parallel power converting means is for electricity in parallel In force conversion system, the power model in 1# inverter and 2# inverter carries out on-off control；Additionally, based on parallel control device Control need, the parallel power transformation system of the present invention also includes for the motor in common load, i.e. the present embodiment, entering The load sensor of row detection, such as the speed detector encoder in the present embodiment or other inspection that can realize rotating detection Survey device；

Motor speed and speed command that speed control detects according to speed detector are controlled, output torque electricity Stream instruction；Torque current command that current controller exports according to speed control and 1# amperometric and 2# current detecting 1# inverter that device detects and the alternating current i of 2# inverter ac side₁、i₂Being controlled, output 1# controls Voltage force respectively Square component and 2# control voltage moment components；The 1# that calculation of circulating current device detects according to 1# amperometric and 2# amperometric Inverter and the alternating current i of 2# inverter ac side₁、i₂Calculate respective circulation value；Circulation controller is then according to calculation of circulating current Circulation value and circulation instruction (usually zero) that device calculates are controlled, and output controls voltage loop current suppression component；1# modulates The 1# that signal generator controls voltage moment components and the output of 1# circulation controller according to the 1# that current controller exports controls electricity Pressure loop current suppression component generates the modulated signal of 1# inverter and delivers to 1#PWM unit, and 2# modulated signal maker is according to electric current The 2# of controller output controls the 2# of voltage moment components and the output of 2# circulation controller and controls the generation of voltage loop current suppression component The modulated signal of 2# inverter also delivers to 2#PWM unit；

Two carrier signal generators generate carrier signal respectively；1#PWM unit and 2#PWM unit are respectively according to its carrier wave Carrier signal and the output of 1# modulated signal maker and 2# modulated signal maker that signal generator generates generate respectively 1# switching signal and 2# switching signal, 1# switching signal and 2# switching signal are being delivered to after the necessary process such as drive amplification respectively Power model in 1# inverter and 2# inverter carries out on-off control.

In selected two carrier signal generators wherein any one as reference carrier signal generator, (in Fig. 1,2# carries Wave generator is chosen to be reference carrier signal generator), its output carrier signal then on the basis of carrier wave, another carry Wave generator is as carrier signal generator to be adjusted；

Spill current computer is according to 1# inverter and the electric current i of 2# inverter ac side₁、i₂Calculate spill current；

1# spill current size counter calculates 1# power converter according to the calculated spill current of spill current computer Spill current size, 1# phase regulator is big according to the spill current of 1# spill current size counter calculated 1# power converter Little output phase adjustment also delivers to 1# carrier signal generator；1# carrier signal generator exports according to 1# phase regulator Its carrier signal phase exported is adjusted by phase adjustment.

The method that the carrier signal phase that carrier signal generator is exported by phase regulator is adjusted includes walking as follows Rapid:

Step 1: selected reference carrier signal generator and carrier signal generator to be adjusted；

Two carrier signal generators of control device constituting parallel power converting means are selected therein any one Individual as reference carrier signal generator (in Fig. 1,2# carrier signal generator is chosen to be reference carrier signal generator), its The carrier signal of output then on the basis of carrier wave, another carrier signal generator is as carrier signal generator to be adjusted (in Fig. 1 1# carrier signal generator is chosen to be carrier signal generator to be adjusted), the carrier signal of its output is then carrier wave to be adjusted Signal.

Step 2: spill current computer calculates the spill current in k moment；

According to amperometric testing result calculate corresponding to carrier signal generator to be adjusted inverter electric current with Corresponding to the difference between the electric current of the inverter of carrier signal generator to be adjusted as spill current.

Step 3: spill current size counter calculates spill current size f in k moment according to the spill current in k moment₁；

Spill current size counter is by being expressed as by spill current with spill current for certainly for the calculating of spill current size The monotonic increasing function f of variable realizes；Specifically, monotonic increasing function f can with take in following form any one:

F (t)=Σ_j|i_{cir_j}(t)|; f(t)=max_j|i_{cir_j}(t)|;

$f\left(t\right)={\mathrm{\&Sigma;}}_j\left(i_{{\mathrm{cir}}_j}^m\left(t\right)\right);f\left(t\right)={\max }_j\left(i_{\mathrm{cir}\_j}^m\left(t\right)\right);$

$f\left(t\right)={\mathrm{\&Sigma;}}_j{\left(i_{\mathrm{cir}\_j}^2\left(t\right)\right)}^{(1/n)};f\left(t\right)={\max }_j{\left(i_{\mathrm{cir}\_j}^2\left(t\right)\right)}^{(1/n)};$

$f\left(t\right)={\mathrm{\&Sigma;}}_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}\left|i_{\mathrm{cir}\_j}\left(t\right)\right|\mathrm{dt};f\left(t\right)=\frac{1}{\mathrm{\&Delta;t}}{\mathrm{\&Sigma;}}_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}\left|i_{\mathrm{cir}\_j}\left(t\right)\right|\mathrm{dt};$

$f\left(t\right)={\max }_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}\left|i_{\mathrm{cir}\_j}\left(t\right)\right|\mathrm{dt};f\left(t\right)=\frac{1}{\mathrm{\&Delta;t}}{\max }_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}\left|i_{\mathrm{cir}\_j}\left(t\right)\right|\mathrm{dt};$

$f\left(t\right)={\mathrm{\&Sigma;}}_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}{i}_{\mathrm{cir}\_j}^m\left(t\right)\mathrm{dt};f\left(t\right)=\frac{1}{\mathrm{\&Delta;t}}{\mathrm{\&Sigma;}}_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}{i}_{\mathrm{cir}\_j}^m\left(t\right)\mathrm{dt};$

$f\left(t\right)={\max }_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}{i}_{\mathrm{cir}\_j}^m\left(t\right)\mathrm{dt};f\left(t\right)=\frac{1}{\mathrm{\&Delta;t}}{\max }_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}{i}_{\mathrm{cir}\_j}^m\left(t\right)\mathrm{dt};$

$f\left(t\right)={\mathrm{\&Sigma;}}_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}{\left(i_{\mathrm{cir}\_j}^2\left(t\right)\right)}^{(1/n)}\mathrm{dt};f\left(t\right)=\frac{1}{\mathrm{\&Delta;t}}{\mathrm{\&Sigma;}}_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}{\left(i_{\mathrm{cir}\_j}^2\left(t\right)\right)}^{(1/n)}\mathrm{dt};$

$f\left(t\right)={\max }_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}{\left(i_{\mathrm{cir}\_j}^2\left(t\right)\right)}^{(1/n)}\mathrm{dt};f\left(t\right)=\frac{1}{\mathrm{\&Delta;t}}{\max }_j{\&Integral;}_t^{t+\mathrm{\&Delta;t}}{\left(i_{\mathrm{cir}\_j}^2\left(t\right)\right)}^{(1/n)}\mathrm{dt}$

In formula, | * | is signed magnitude arithmetic(al) symbol, and m is positive even numbers, and n is any positive integer, and j is each electricity of changer to be adjusted Stream numbering, Δ t is any arithmetic number；Or

F (k)=∑_j|i_{cir_j}(k)|；F (k)=max_j|i_{cir_j}(k)|；

$f\left(k\right)={\mathrm{\&Sigma;}}_j\left(i_{{\mathrm{cir}}_j}^m\left(k\right)\right);f\left(k\right)={\max }_j\left(i_{\mathrm{cir}\_j}^m\left(k\right)\right);$

$f\left(k\right)={\mathrm{\&Sigma;}}_j{\left(i_{\mathrm{cir}\_j}^2\left(k\right)\right)}^{(1/n)};f\left(k\right)={\max }_j{\left(i_{\mathrm{cir}\_j}^2\left(k\right)\right)}^{(1/n)};$

$f\left(k\right)={\mathrm{\&Sigma;}}_j{\mathrm{\&Sigma;}}_{p=k-l}^k\left|i_{\mathrm{cir}\_j}\left(p\right)\right|;f\left(k\right)=\frac{1}{l\&times;T_{\mathrm{car}}}{\mathrm{\&Sigma;}}_j{\mathrm{\&Sigma;}}_{p=k-l}^k\left|i_{\mathrm{cir}\_j}\left(p\right)\right|;$

$f\left(k\right)={\max }_j{\mathrm{\&Sigma;}}_{p=k-l}^k\left|i_{\mathrm{cir}\_j}\left(p\right)\right|;f\left(k\right)=\frac{1}{l\&times;T_{\mathrm{car}}}{\max }_j{\mathrm{\&Sigma;}}_{p=k-l}^k\left|i_{\mathrm{cir}\_j}\left(p\right)\right|;$

$f\left(k\right)={\mathrm{\&Sigma;}}_j{\mathrm{\&Sigma;}}_{p=k-l}^k{i}_{\mathrm{cir}\_j}^m\left(p\right);f\left(k\right)=\frac{1}{l\&times;T_{\mathrm{car}}}{\mathrm{\&Sigma;}}_j{\mathrm{\&Sigma;}}_{p=k-l}^k{i}_{\mathrm{cir}\_j}^m\left(p\right);$

$f\left(k\right)={\max }_j{\mathrm{\&Sigma;}}_{p=k-l}^k{i}_{\mathrm{cir}\_j}^m\left(p\right);f\left(k\right)=\frac{1}{l\&times;T_{\mathrm{car}}}{\max }_j{\mathrm{\&Sigma;}}_{p=k-l}^k{i}_{\mathrm{cir}\_j}^m\left(p\right);$

$f\left(k\right)={\mathrm{\&Sigma;}}_j{\mathrm{\&Sigma;}}_{p=k-l}^k{\left(i_{\mathrm{cir}\_j}^2\left(p\right)\right)}^{(1/n)}$ $f\left(k\right)=\frac{1}{l\&times;T_{\mathrm{car}}}{\mathrm{\&Sigma;}}_j{\mathrm{\&Sigma;}}_{p=k-l}^k{\left(i_{\mathrm{cir}\_j}^2\left(p\right)\right)}^{(1/n)};$

$f\left(k\right)={\max }_j{\mathrm{\&Sigma;}}_{p=k-l}^k{\left(i_{\mathrm{cir}\_j}^2\left(p\right)\right)}^{(1/n)};f\left(k\right)=\frac{1}{l\&times;T_{\mathrm{car}}}{\max }_j{\mathrm{\&Sigma;}}_{p=k-l}^k{\left(i_{\mathrm{cir}\_j}^2\left(p\right)\right)}^{(1/n)}$

In formula, | * | is signed magnitude arithmetic(al) symbol, and m is positive even numbers, l and n is any positive integer, and nonnegative integer l≤k, and j is Each phase current numbering of power converter, T_carIt it is the cycle of described carrier wave.

Obviously, utilizing function f, spill current size counter can calculate, according to the spill current of each power converter, electricity of going on business Stream size f₁And f₂。

Step 4: phase regulator utilizes phase-shift phase to be adjusted k moment carrier signal phase；

Phase regulator is increased or decreased a phase-shift phase in the carrier signal phase of power converter, and phase-shift phase is one non- Zero real number；In view of increasing the phase-shift phase equivalence negative with reduction of positive phase-shift phase, increasing negative phase-shift phase and reduce positive phase shift Amount equivalence, simple for statement, follow-up explanation adjusts mode by above-mentioned four kinds unified for increasing by a phase-shift phase；K+g (g >=1, Under normal circumstances, g=1) carrier signal phase in moment can be expressed as:

Ph(k+g)←Ph(k)+ΔPh

In formula, Ph (k+1) and Ph (k) is k moment and the carrier signal phase in k+1 moment respectively, and Δ Ph is phase-shift phase, ← For assignment operator；

After obtaining the carrier phase in k+g moment, 1# carrier signal generator is i.e. according to the phase generated carrier letter after adjusting Number, the carrier signal after 1#PWM unit adjusts according to phase place is modulated.

Step 5: spill current computer calculates the spill current in k+g (g >=1) moment；

Step 6: it is big that spill current size counter calculates the spill current in k+g (g >=1) moment according to the spill current in k+g moment Little f₂；

Because the modulation of k+g (g >=1) moment 1#PWM unit is that the carrier signal after adjusting based on phase place is carried out, therefore abide by Following spill current size computational methods in step 1 utilizes the spill current in k+g (g >=1) moment can calculate carrier signal phase tune Spill current size f in parallel power converting means after whole₂。

Step 7: phase regulator determines that phase place adjusts the situation of change of pre-post difference size of current；

According to the f in step 3₁With the f in step 6₂, directly judge f₁And f₂Between magnitude relationship, or first calculate phase Spill current size variation amount Δ f=f before and after the adjustment of position₂-f₁, it is poor to judge further according to the symbol of spill current size variation amount Δ f Electric current is to increase or reduce after phase place adjusts than before adjusting, or judges spill current size variation spill current size variation amount Relation between Δ f and preset value α and β (α < β), i.e. judges in Δ f≤α, α < Δ f < β, β≤Δ f, which relational expression is set up.

Step 8: the situation of change of the spill current size that phase regulator obtains according to step 7 adjusts k+g (g >=1) moment Carrier signal phase；

The adjustment of k+g (g >=1) moment carrier signal phase can take following arbitrary rule:

Rule 1: if f₁>f₂, i.e. Δ f < 0, then keep Ph (k+g) currency constant, otherwise Ph (k+g) ← Ph (k), Δ Ph ←-Δ Ph；

Rule 2: if f₁>f₂, i.e. Δ f < 0, then keep Ph (k+g) currency constant, otherwise Ph (k+g) ← Ph (k)-Δ Ph；

Rule 3: if Δ f≤α, keep Ph (k+g) currency constant, if α < Δ f < β, Ph (k+g) ← Ph (k), if β≤Δ F, then Ph (k+g) ← Ph (k)-Δ Ph.

Actually rule 2 is equivalent to: (Δ f) × Δ Ph, wherein sign (*) is symbol letter to Ph (k+g) ← Ph (k)-sign Number.

In above-mentioned adjustment law, phase-shift phase Δ Ph is to meet following condition:

0<ΔPh≤0.5×T_car×ω_e

Wherein, T_carIt is the cycle of described carrier wave, ω_eIt is electrical angle speed.

Additionally, phase-shift phase Δ Ph be one preset steady state value, it is also possible to be one with spill current big small function f and/or difference electricity Stream size variation amount Δ f is the function of independent variable, and phase-shift phase Δ Ph can calculate according to following arbitrary formula:

ΔPh=ζ×f×ΔPh₀, Δ Ph=ζ × Δ f × Δ Ph₀,

ΔPh=ζ×f×ΔPh₀+δ×Δf×ΔPh₀

In formula, benchmark phase-shift phase Δ Ph₀Being steady state value set in advance, ζ and δ is constant.

The circular current control method of the present invention is persistently carried out for the adjustment of carrier phase, or according to some cycles or work as Perform s (s >=1) when spill current big small function f exceedes threshold value set in advance secondary, or continuously perform until spill current size letter Number f stops less than after threshold value set in advance again.

Obviously, in the present embodiment, the reference carrier signal phase invariant of reference carrier signal generator output, be only The phase place of the carrier signal to be adjusted exporting carrier signal generator to be adjusted is adjusted.

In parallel power changer field, it is however generally that, circulation is defined as each phase current of power converter with all Difference between the current average of changer AC correspondence phase, but also dependent on needing to carry out different definition, such as: select certain Changer on the basis of one power converter, then the circulation of remaining power converter may be defined as each phase current of this power converter Difference between the current value of phase corresponding with transformation of criterion device, now, calculation of circulating current device and spill current computer can unite two into one.

Embodiment 2

As in figure 2 it is shown, the present embodiment is similar to Example 1, difference is to have minused circulation controller and modulated signal generation Device, the output of current controller is i.e. sent to PWM unit as modulated signal, and remaining is same as in Example 1.

Claims (8)

1. the circular current control method of a parallel power converting means, it is characterised in that: described control method comprises the steps:

Step 1: selected reference carrier signal generator and carrier signal generator to be adjusted；

Step 2: calculate the spill current in k moment；

Step 3: calculate the spill current size in k moment according to the spill current in k moment；

Step 4: utilize phase-shift phase that k moment carrier signal phase is adjusted；

Step 5: calculate the spill current in k+g moment, wherein g >=1；

Step 6: calculate the spill current size in k+g moment, wherein g >=1 according to the spill current in k+g moment；

Step 7: determine that phase place adjusts the situation of change of pre-post difference size of current；

Step 8: adjust the carrier signal phase in k+g moment, wherein g >=1 according to the situation of change of spill current size.

The circular current control method of parallel power converting means the most according to claim 1, it is characterised in that: described step 3 It is by spill current being expressed as the monotonic increasing function with spill current as independent variable with calculating for spill current size in step 6 Realize.

The circular current control method of parallel power converting means the most according to claim 1, it is characterised in that: described step 8 According to following arbitrary rule, carrier signal phase is adjusted:

Rule 1: if f₁>f₂, i.e. Δ f < 0, then keep Ph (k+g) currency constant, otherwise Ph (k+g) ← Ph (k), Δ Ph ←- ΔPh；

Rule 2: if f₁>f₂, i.e. Δ f < 0, then keep Ph (k+g) currency constant, otherwise Ph (k+g) ← Ph (k)-Δ Ph；

Rule 3: if Δ f≤α, keep Ph (k+g) currency constant, if α < Δ f < β, Ph (k+g) ← Ph (k), if β≤Δ f, then Ph (k+g) ← Ph (k)-Δ Ph；

Wherein f₁For the spill current size in k moment in step 3；

f₂For the spill current size in k+g moment in step 6；

Spill current size variation amount Δ f=f₂-f₁；

Ph (k) is the carrier signal phase in k moment；

Ph (k+g) is the carrier signal phase in k+g moment；

Δ Ph is phase-shift phase；

← for assignment operator；

α, β are respectively preset value, and α < β.

The circular current control method of parallel power converting means the most according to claim 3, it is characterised in that: described phase-shift phase Δ Ph meets following condition:

0<ΔPh≤0.5×T_car×ωe

Wherein T_carBeing the cycle of described carrier wave, ω e is electrical angle speed.

The circular current control method of parallel power converting means the most according to claim 3, it is characterised in that: described phase-shift phase Δ Ph is a steady state value preset；Or,

Described phase-shift phase Δ Ph be one with spill current big small function f and/or spill current size variation amount Δ f the letter as independent variable Number；Phase-shift phase Δ Ph calculates according to following arbitrary formula:

Δ Ph=ζ × f × Δ Ph₀；

Δ Ph=ζ × Δ f × Δ Ph₀；

Δ Ph=ζ × f × Δ Ph₀+δ×Δf×ΔPh₀

In formula, benchmark phase-shift phase Δ Ph₀Being steady state value set in advance, ζ and δ is constant.

The circular current control method of parallel power converting means the most according to claim 1, it is characterised in that: described circulation control Method processed is persistently carried out for the adjustment of carrier phase；Or

Perform s time when exceeding threshold value set in advance according to some cycles or the size of current function f that is on duty, wherein s >=1；Or Continuously perform until spill current big small function f stops less than after threshold value set in advance again.

7., for a control device for parallel power converting means, described control device includes:

Current controller；Current controller is controlled according to the current feedback values of current instruction value and each parallel power converting means System, exports modulated signal；

Carrier signal generator；Carrier signal generator generates the carrier signal needed for PWM unit；

PWM unit；Modulated signal that PWM unit exports according to current controller and the carrier signal that carrier signal generator generates Carrying out pulsewidth modulation, output is for controlling the switching signal of power model；

It is characterized in that, also include:

Spill current computer；Spill current computer calculates spill current according to the current feedback values of each parallel power converting means；

Spill current size counter；Spill current size counter calculates spill current according to the result of calculation of described spill current computer Size；

Phase regulator；The spill current size that phase regulator exports according to spill current size counter, utilize claim 1 to The carrier signal phase that carrier signal generator to be adjusted is generated by the method described in 6 any one is adjusted.

8., for a control device for parallel power converting means, described control device includes:

Current controller；Current controller is controlled according to the current feedback values of current instruction value and each parallel power converting means System, output controls voltage moment components；

Calculation of circulating current device；Calculation of circulating current device calculates circulation value according to the current feedback values of each parallel power converting means；

Circulation controller；The circulation value that circulation controller exports according to circulation command value and described calculation of circulating current device is controlled, Output controls voltage loop current suppression component；

Carrier signal generator；Carrier signal generator generates the carrier signal needed for PWM unit；

Modulated signal maker；Control voltage moment components that modulated signal maker exports according to described current controller and The control voltage loop current suppression component of described circulation controller output generates modulated signal；

PWM unit；Modulated signal that PWM unit exports according to described modulated signal maker and carrier signal generator generate Carrier signal carries out pulsewidth modulation, and output is for controlling the switching signal of power model；

It is characterized in that, also include:

Spill current computer；Spill current computer calculates spill current according to the current feedback values of each parallel power converting means；

Spill current size counter；Spill current size counter calculates spill current according to the result of calculation of described spill current computer Size；

Phase regulator；The spill current size that phase regulator exports according to spill current size counter, utilize claim 1 to The carrier signal phase that carrier signal generator to be adjusted is generated by the method described in 6 any one is adjusted.