CN104242700A - Nonlinear control method of inverter and equipment thereof - Google Patents

Abstract

The invention provides a nonlinear control method of an inverter and equipment thereof. The nonlinear control method comprises the steps of: acquiring a deviation of an output voltage, wherein the deviation of the output voltage is a difference between a given voltage reference value and an output voltage of an inverter; when the deviation of the output voltage increases in a positive direction, continuously reducing an inner-right feedback coefficient of an inverter inductor current to a first preset value; and the deviation of the output voltage increases in a negative direction, continuously increasing the inner-right feedback coefficient of the inverter inductor current to a second preset value. When a load reduces suddenly, the output voltage of the inverter increases; the deviation of the output voltage increases in the negative direction; the inertia of the current inner ring increases; the gain reduces; and action of the current inner ring slows, thereby performing a function of weakening voltage increase. When the output voltage reduces, the deviation of the output voltage increases in the positive direction; the inertia of the current inner ring reduces; the gain increases; and action of the current inner ring quickens, thereby performing a function of reducing voltage reduction. The nonlinear control method of the inverter further has functions of: improving adaptability of the inverter to the load, enlarging damping to oscillation, and improving system stability.

Description

A kind of nonlinear control method of inverter and equipment

Technical field

The present invention relates to inverter Closed loop Control field, particularly a kind of nonlinear control method of inverter and equipment.

Background technology

Adapt to the ability of load changing to strengthen inverter, existing voltage source inverter generally adopts the double-closed-loop control method of current inner loop and outer voltage.

The effect of current inner loop is inertia by feedback reduction system thus improves systematic function, and current inner loop is divided into inductive current inner ring and capacitive current inner ring two kinds.Wherein, inductive current inner ring is adopted to control to facilitate current-limiting protection; be because in inverter system, a lot of electric device can bear maximum voltage and current is conditional, control effectively to avoid overcurrent to occur by inductive current inner ring, and then protection device be not damaged.The ability adopting capacitive current inner ring to control reply load changing is eager to excel, but is not easy to control electric current.

In some application scenario, such as, there is grid-connected and photovoltaic DC-to-AC converter that is separate inverter unit dual-mode functions.In order to electric current when effective control inverter is incorporated into the power networks, the general control method adopting inductive current inner ring.There is dual mode operated inverter, want that there is good adaptive load ability when independent inverter mode runs, general employing load-current feedforward control or employing capacitor current feedback control, but these modes add the consumption of hardware resource undoubtedly, also reduce the reliability of system equally.

If the double-closed-loop control device under inverter independence inverter mode is preset parameter PI controller, so should according to the parameter designing PI controller during inverter no-load running when designing PI controller, at this moment inverter is equivalent to a underdamped second-order system, voltage overshoot is larger, therefore voltage PI controller gain can not be too large, otherwise the stability of inverter will reduce.

When inverter run with load, need the voltage of stable output, at this moment just need the build-in attribute of change system to meet the requirement of load changing.

Therefore, how to provide a kind of nonlinear control method of inverter, under the condition not increasing system hardware, reach good dynamic property, improving the stability of system, is those skilled in the art's technical issues that need to address.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of nonlinear control method and equipment of inverter, can not increase system hardware, makes inverter reach good dynamic property, improves the stability of system.

The embodiment of the present invention provides a kind of nonlinear control method of inverter, comprises the following steps:

Obtain the deviation e of output voltage, the deviation e of described output voltage is given voltage reference value with inverter output voltage u _odifference;

When the deviation e of output voltage increases to positive direction, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point;

When the deviation e of output voltage increases to negative direction, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point.

Preferably, also comprise:

If the absolute value of the deviation e of output voltage is less than the first preset value delta, then inverter inductance current inner loop feedback coefficient is constant.

Preferably, described when the deviation e of output voltage increases to positive direction, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point; Be specially: if the absolute value of the deviation e of output voltage is more than or equal to described first preset value delta and is less than the second predetermined value a, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point;

When the deviation e of output voltage increases to negative direction, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point, be specially: if the absolute value of the deviation e of output voltage is more than or equal to described second predetermined value a, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point.

Preferably, the inductive current i of described inductive current inner loop feedback " _lthe inductive current i exported with inductive current inner ring _lrelational expression be specially:

i" _L=i _L[1-Kf(e)]；

Wherein, described inductive current inner loop feedback coefficient is 1-Kf (e);

F (e) is a band dead band saturation nonlinearity function, $f\left(e\right)=\left\{\begin{array}{c}0,\left|e\right|<\mathrm{\&Delta;}\\ k(e-\mathrm{\&Delta;}),\mathrm{\&Delta;}\&le;\left|e\right|a\\ k(a-\mathrm{\&Delta;}),\left|e\right|\&GreaterEqual;a\end{array}\right.;$

Wherein, K and k is setting coefficient.

Preferably, the deviation e and the inductive current inner ring sensing function that are obtained the output voltage of nonlinear Control by described inductive current inner loop feedback coefficient are:

$\frac{i_L}{e}=\frac{K_1{K}_2{K}_{\mathrm{PWM}}}{\mathrm{sL}+R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Wherein, K ₁, K ₂be respectively used to the simplification coefficient representing voltage PI controller and current PI controller;

Equivalent time constant is:

$T=\frac{L}{R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Open-loop gain is:

k ₀=K ₁K ₂K _PWM/(R+K ₂K _PWM[1-Kf(e)])。

The embodiment of the present invention also provides a kind of nonlinear Control equipment of inverter, comprising: output voltage deviation obtains unit, deviation judging unit, feedback factor adjustment unit;

Described output voltage deviation obtains unit, for by given voltage reference value with inverter output voltage u _odifference obtain the deviation e of output voltage;

Described deviation judging unit, for judging that the deviation e of described output voltage increases to positive direction, or increases to negative direction;

Described feedback factor adjustment unit, when the deviation e of described output voltage increases to positive direction, for continuing to be reduced to the first set point by inverter inductance current inner loop feedback coefficient; When the deviation e of described output voltage increases to negative direction, for described inductive current inner loop feedback coefficient is continued to increase to the second set point.

Preferably, described deviation judging unit, also for judging whether the absolute value of the deviation e of described output voltage is less than the first preset value delta;

Described feedback factor adjustment unit, when the absolute value of the deviation e of described output voltage is less than the first preset value delta, for not adjusting described inductive current inner loop feedback coefficient.

Preferably, described deviation judging unit comprises: the first judgment sub-unit;

When described first judgment sub-unit judges that the absolute value of the deviation e of output voltage is more than or equal to described first preset value delta and is less than the second predetermined value a, then described inductive current inner loop feedback coefficient continues to be reduced to the first set point by feedback factor adjustment unit;

When described first judgment sub-unit judges that the absolute value of the deviation e of output voltage is more than or equal to described second predetermined value a, then described inductive current inner loop feedback coefficient continues to increase to the second set point by described feedback factor adjustment unit.

Preferably, the inductive current i of described inductive current inner loop feedback " _lthe inductive current i exported with inductive current inner ring _lrelational expression be specially:

i" _L=i _L[1-Kf(e)]；

Wherein, described inductive current inner loop feedback coefficient is 1-Kf (e);

F (e) is a band dead band saturation nonlinearity function, $f\left(e\right)=\left\{\begin{array}{c}0,\left|e\right|<\mathrm{\&Delta;}\\ k(e-\mathrm{\&Delta;}),\mathrm{\&Delta;}\&le;\left|e\right|a\\ k(a-\mathrm{\&Delta;}),\left|e\right|\&GreaterEqual;a\end{array}\right.;$

Wherein, K and k is setting coefficient.

Preferably, the deviation e and the inductive current inner ring sensing function that are obtained the output voltage of nonlinear Control by described inductive current inner loop feedback coefficient are:

$\frac{i_L}{e}=\frac{K_1{K}_2{K}_{\mathrm{PWM}}}{\mathrm{sL}+R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Wherein, K ₁, K ₂be respectively used to the simplification coefficient representing voltage PI controller and current PI controller;

Equivalent time constant is:

$T=\frac{L}{R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Open-loop gain is:

k ₀=K ₁K ₂K _PWM/(R+K ₂K _PWM[1-Kf(e)])。

Compared with prior art, the present invention has the following advantages:

Method provided by the invention carries out nonlinear Control to inverter, the feedback factor of inductive current inner ring is adjusted by the deviation of output voltage, when load reduces suddenly, the output voltage of inverter rises, the deviation e of output voltage is that negative direction increases, and such current inner loop inertia increases, and gain reduces, current inner loop reaction is slack-off, has the effect weakening voltage rise; When output voltage declines, the deviation e of output voltage is that positive direction increases, and current inner loop inertia reduces, and gain increases, and current inner loop reaction accelerates, and has the effect reducing voltage drop.Therefore, the present invention adopts the adaptive capacity of nonlinear Control to load to be strengthened to inverter, increases the damping to vibration, improves the stability of system.

Accompanying drawing explanation

Fig. 1 is the outer voltage inductive current inner ring double-closed-loop control theory diagram of inverter in prior art;

Fig. 2 is the transfer function model schematic diagram that Fig. 1 is corresponding;

Fig. 3 is nonlinear control method embodiment one flow chart of inverter provided by the invention;

Fig. 4 is nonlinear control method embodiment two flow chart of inverter provided by the invention;

Fig. 5 is the transfer function model schematic diagram of nonlinear Control provided by the invention;

Fig. 6 is the transfer function model schematic diagram after simplification provided by the invention;

Fig. 7 is inverter equivalent voltage outer shroud current inner loop transfer function schematic diagram provided by the invention;

Fig. 8 is a concrete simulated effect figure provided by the invention;

Fig. 9 is nonlinear Control apparatus embodiments one schematic diagram of inverter provided by the invention;

Figure 10 is nonlinear Control apparatus embodiments two schematic diagram of inverter provided by the invention.

Embodiment

Understand better to enable those skilled in the art and implement technical scheme of the present invention, the outer voltage first introduced below in inverter system controls and current inner loop controls.

See Fig. 1, this figure is the outer voltage inductive current inner ring control principle block diagram of inverter in prior art.

In figure, microprocessor is responsible for data acquisition and control.

Inverter output voltage u ₀after voltage sensor, microprocessor carries out acquisition process and and given voltage reference value compare, voltage difference exports given current reference value after voltage controller , the actual inductive current i that inverter exports _lthrough current sensor collection and and given current reference value compare, current differential, after current controller process, exports control inverter after the algorithm process that recycling is relevant.As required, inverter can access and excise load Z, output voltage u ₀fluctuate within the specific limits.

See Fig. 2, this figure is the transfer function model schematic diagram that Fig. 1 is corresponding.

As shown in Figure 2, modeling analysis is carried out to inverter, ignores the impedance of connection and the whole system nonlinear element little to performance impact, have:

Voltage controller transfer function:

$G_v\left(s\right)=K_{\mathrm{vp}}\frac{1+T_{\mathrm{vi}}s}{T_{\mathrm{vi}}s}---\left(1\right)$

Current controller transfer function:

$G_i\left(s\right)=K_{\mathrm{ip}}\frac{1+T_{\mathrm{ii}}s}{T_{\mathrm{ii}}s}---\left(2\right)$

Inverter model is divided into switch element and inductive part transfer function:

$G\left(s\right)=\frac{K_{\mathrm{PWM}}}{\mathrm{SL}+R}---\left(3\right)$

Capacitance transfer function:

$G_c\left(s\right)=\frac{1}{\mathrm{sC}}---\left(4\right)$

In Fig. 2, the inductive current of current sensor collection is equivalent to 1:1 after treatment and feeds back, and is all be 1 carry out processing by the feedback factor of inductive current in prior art.

And in the present invention, the feedback factor of inductive current is adjusted, the feedback factor of dynamic conditioning inductive current is carried out according to the deviation of output voltage.

For enabling above-mentioned purpose of the present invention, feature and advantage become apparent more, are described in detail the specific embodiment of the present invention below in conjunction with accompanying drawing.

See Fig. 3, this figure is nonlinear control method embodiment one flow chart of inverter provided by the invention.

S301: the deviation e obtaining output voltage, the deviation e of described output voltage is given voltage reference value with inverter output voltage u _odifference;

It should be noted that, inverter output voltage u _obeing DC quantity, is the DC quantity of alternating voltage after d-q coordinate transform that inverter exports.

Given voltage reference value also be DC quantity.

S302: when the deviation e of output voltage increases to positive direction, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point;

When load increases suddenly, the output voltage of corresponding inverter can decline instantaneously, will the deviation positive direction of output voltage be caused to increase like this, and namely deviation increases.Therefore, need inductive current inner loop feedback coefficient to continue to be reduced to the first set point.

S303: when the deviation e of output voltage increases to negative direction, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point.

When load reduces suddenly, the output voltage of corresponding inverter can increase instantaneously, will the deviation negative direction of output voltage be caused to increase like this, and namely deviation reduces.Therefore, need inductive current inner loop feedback coefficient to continue to increase to the second set point.It should be noted that, described deviation e is likely positive number, is likely negative.When described e refers to that e is positive number to positive direction increase, e changes to large direction; When described e refers to that e is negative to negative direction increase, the absolute value of e changes to large direction.

Be understandable that, the first set point and the second set point are the values preset, and have relation with inverter system itself, and inverter system is different, then the concrete value of set point is different.

Method provided by the invention carries out nonlinear Control to inverter, the feedback factor of inductive current inner ring is adjusted by the deviation of output voltage, when load reduces suddenly, the output voltage of inverter rises, the deviation e of output voltage is that negative direction increases, and such current inner loop inertia increases, and gain reduces, current inner loop reaction is slack-off, has the effect weakening voltage rise; When output voltage declines, the deviation e of output voltage is that positive direction increases, and current inner loop inertia reduces, and gain increases, and current inner loop reaction accelerates, and has the effect reducing voltage drop.Therefore, the present invention adopts the adaptive capacity of nonlinear Control to load to be strengthened to inverter, increases the damping to vibration, improves the stability of system.

See Fig. 4, this figure is nonlinear control method embodiment two flow chart of inverter provided by the invention.

The nonlinear control method of the inverter that the present embodiment provides also comprises:

S401 and S301 is identical, does not repeat them here.

S402: if the absolute value of the deviation e of output voltage is less than the first preset value delta, then inverter inductance current inner loop feedback coefficient is constant.

S403: described when the deviation e of output voltage increases to positive direction, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point; Be specially: if the absolute value of the deviation e of output voltage is more than or equal to described first preset value delta and is less than the second predetermined value a, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point;

S404: when the deviation e of output voltage increases to negative direction, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point, be specially: if the absolute value of the deviation e of output voltage is more than or equal to described second predetermined value a, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point.

The method of nonlinear Control is introduced below in conjunction with formula.

The inductive current i of described inductive current inner loop feedback " _lthe inductive current i exported with inductive current inner ring _lrelational expression be specially:

i" _L=i _L[1-Kf(e)]； （5）

Wherein, described inductive current inner loop feedback coefficient is 1-Kf (e);

F (e) is a band dead band saturation nonlinearity function, $f\left(e\right)=\left\{\begin{array}{c}0,\left|e\right|<\mathrm{\&Delta;}\\ k(e-\mathrm{\&Delta;}),\mathrm{\&Delta;}\&le;\left|e\right|a\\ k(a-\mathrm{\&Delta;}),\left|e\right|\&GreaterEqual;a\end{array}\right.;$

Wherein, K and k is coefficient, specifically can set according to the needs of concrete inverter system.

See Fig. 5, this figure is the transfer function model schematic diagram of nonlinear Control provided by the invention.

As can be seen from Figure 5, invention increases the difference of the transfer function after nonlinear Control and the transfer function shown in Fig. 2.

Nonlinear element f (e) is added in Fig. 5.

Consider that the proportional component of voltage PI controller, current PI controller produces major effect to the dynamic response of system, use K respectively ₁, K ₂the voltage controller transfer function in formula (1) and (2) and current controller transfer function is replaced to carry out Simplified analysis.

It should be noted that, current controller in the embodiment of the present invention and voltage controller are only introduced for PI controller, be understandable that, at control field, controller can adoption rate controller, pi controller or proportional plus integral plus derivative controller.The present invention does not specifically limit the particular type of controller.

Transfer function after simplification is see Fig. 6.

The deviation e of output voltage of the prior art and inductive current i _lthe pass of inner ring transfer function is:

$\frac{i_L}{e}=\frac{K_1{K}_2{K}_{\mathrm{PWM}}}{\mathrm{sL}+R+K_2{K}_{\mathrm{PWM}}}---\left(6\right)$

The time constant of equivalence is: T=L/ (R+K ₂k _pWM), gain is: k _o=K ₁k ₂k _pWM/ (R+K ₂k _pWM).

The deviation e of the output voltage that nonlinear Control provided by the invention is corresponding and inductive current i _lthe pass of inner ring transfer function is:

$\frac{i_L}{e}=\frac{K_1{K}_2{K}_{\mathrm{PWM}}}{\mathrm{sL}+R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}---\left(7\right)$

After transformation, the time constant of equivalence becomes: $T=\frac{L}{R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]},$ Gain becomes: k _o=K ₁k ₂k _pWM/ (R+K ₂k _pWM[1-Kf (e)]).

In order to be illustrated more clearly in the technique effect of nonlinear Control provided by the invention, be introduced below in conjunction with an instantiation.

See Fig. 7, this figure is inverter equivalent voltage outer shroud current inner loop transfer function schematic diagram provided by the invention.

According to the requirement of the design of inverter double-closed-loop control, current inner loop is generally according to typical 1 type design, if current PI controller, voltage PI controller designs (when not considering variation PI controller herein according to preset parameter, the equivalence change of current inner loop), inner ring can according to the variation tendency of nonlinear Control, the current inner loop Simplified equivalent model during damping increasing system is equivalent in first box 600, the current inner loop Simplified equivalent model during damping reducing system is equivalent in 3rd frame 700, current inner loop Simplified equivalent model when not changing system damping is equivalent in second frame 800.

Understand better to make this technical staff and implement transfer function corresponding to Fig. 7, being introduced for first box 600 below.

Derivation in conjunction with formula (5) illustrates.

According to the double-closed-loop control pi regulator parameter tuning rule of current inner loop outer voltage in inverter, general current inner loop designs according to typical I type, then the degeneration factor of current inner loop is 1, and now current inner loop can be equivalent to a first order inertial loop.Equivalent time constant is 3Ts(Ts is the sampling time), so transfer function is

In the present invention, nonlinear Control is carried out to inverter, if now inner ring pi regulator parameter constant moves, according to formula (5), must respective change be there is in first order inertial loop gain and time constant when nonlinear Control of equivalence, if inner ring equivalent time constant becomes 2.5Ts, the time constant of current inner loop equivalence $T=\frac{L}{R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]},$ Other parameters do not change, and in description time constant formula, denominator becomes large 1.2 times, then open-loop gain K ₁k ₂k _pWM/ (R+K ₂k _pWM[1-Kf (e)]) become original 1/1.2 times; Together should by after nonlinear Control effect, if the time constant of the first order inertial loop of equivalence becomes 3.5Ts, so gain then becomes 1.16, just can obtain the transfer function in Fig. 7 in first box 600.According to the equivalent model that Fig. 7 is corresponding, simulation parameter is set, just can obtains the simulated effect figure shown in Fig. 8.

See Fig. 8, this figure is a concrete simulated effect figure provided by the invention.

The control object (this object is known for those skilled in the art, and voltage PI controller parameter method for designing a lot, adopts second order " symmetrical best method " here) that typical single order adds integration is equivalent to when inverter is unloaded.

Build PSIM simulation model, given reference voltage is 165, and during beginning, inverter is 0 slow to open from given voltage, inverter band purely resistive is fully loaded with load, and 0.02s drops into load, and 0.06s cuts away load, dead band saturation nonlinearity is set to Δ=3, a=10, and simulation result as shown in Figure 8.

As can be seen from Figure 8, nonlinear Control provided by the invention is when load increases suddenly, and output voltage declines 39, but linear PID controlling of the prior art is when load increases suddenly, and output voltage declines 47.And nonlinear Control provided by the invention is when load declines suddenly, output voltage peak value is 183, and linear PID controlling of the prior art is when load declines suddenly, and output voltage peak value is 207.

Nonlinear control method provided by the invention has better dynamic property when load changing as seen from Figure 8, and the stability of system also increases.

Method provided by the invention, when not increasing hardware cost, can obtain good dynamic property by nonlinear Control.And implementation is simple, can increase the reliability of system.

Based on the nonlinear control method of above-mentioned inverter, present invention also offers the system of the nonlinear Control of inverter, describe its part in detail below in conjunction with specific embodiment.

See Fig. 9, this figure is nonlinear Control apparatus embodiments one schematic diagram of inverter provided by the invention.

The nonlinear Control equipment of the inverter that the present embodiment provides, comprising: output voltage deviation obtains unit 801, deviation judging unit 802, feedback factor adjustment unit 803;

Described output voltage deviation obtains unit 801, for by given voltage reference value with inverter output voltage u _odifference obtain the deviation e of output voltage;

Described deviation judging unit 802, for judging that the deviation e of described output voltage increases to positive direction, or increases to negative direction;

Described feedback factor adjustment unit 803, when the deviation e of described output voltage increases to positive direction, for continuing to be reduced to the first set point by inverter inductance current inner loop feedback coefficient; When the deviation e of described output voltage increases to negative direction, for described inductive current inner loop feedback coefficient is continued to increase to the second set point.

When load increases suddenly, the output voltage of corresponding inverter can decline instantaneously, will the deviation positive direction of output voltage be caused to increase like this, and namely deviation increases.Therefore, need inductive current inner loop feedback coefficient to continue to be reduced to the first set point.

When load reduces suddenly, the output voltage of corresponding inverter can increase instantaneously, will the deviation negative direction of output voltage be caused to increase like this, and namely deviation reduces.Therefore, need inductive current inner loop feedback coefficient to continue to increase to the second set point.

Method provided by the invention carries out nonlinear Control to inverter, the feedback factor of inductive current inner ring is adjusted by the deviation of output voltage, when load reduces suddenly, the output voltage of inverter rises, the deviation e of output voltage is that negative direction increases, and such current inner loop inertia increases, and gain reduces, current inner loop reaction is slack-off, has the effect weakening voltage rise; When output voltage declines, the deviation e of output voltage is that positive direction increases, and current inner loop inertia reduces, and gain increases, and current inner loop reaction accelerates, and has the effect reducing voltage drop.Therefore, the present invention adopts the adaptive capacity of nonlinear Control to load to be strengthened to inverter, increases the damping to vibration, improves the stability of system.

Described deviation judging unit, also for judging whether the absolute value of the deviation e of described output voltage is less than the first preset value delta;

Described feedback factor adjustment unit, when the absolute value of the deviation e of described output voltage is less than the first preset value delta, for not adjusting described inductive current inner loop feedback coefficient.

See Figure 10, this figure is nonlinear Control apparatus embodiments two schematic diagram of inverter provided by the invention.

In the present embodiment, described deviation judging unit 802 comprises: the first judgment sub-unit 802a;

When described first judgment sub-unit 802a judges that the absolute value of the deviation e of output voltage is more than or equal to described first preset value delta and is less than the second predetermined value a, then described inductive current inner loop feedback coefficient continues to be reduced to the first set point by feedback factor adjustment unit 803;

When described first judgment sub-unit 802a judges that the absolute value of the deviation e of output voltage is more than or equal to described second predetermined value a, then described inductive current inner loop feedback coefficient continues to increase to the second set point by described feedback factor adjustment unit 803.

The inductive current i of described inductive current inner loop feedback " _lthe inductive current i exported with inductive current inner ring _lrelational expression be specially:

i" _L=i _L[1-Kf(e)]；

Wherein, described inductive current inner loop feedback coefficient is 1-Kf (e);

F (e) is a band dead band saturation nonlinearity function, $f\left(e\right)=\left\{\begin{array}{c}0,\left|e\right|<\mathrm{\&Delta;}\\ k(e-\mathrm{\&Delta;}),\mathrm{\&Delta;}\&le;\left|e\right|a\\ k(a-\mathrm{\&Delta;}),\left|e\right|\&GreaterEqual;a\end{array}\right.;$

Wherein, K and k is coefficient, specifically can set according to the needs of concrete inverter system.The deviation e and the inductive current inner ring sensing function that are obtained the output voltage of nonlinear Control by described inductive current inner loop feedback coefficient are:

$\frac{i_L}{e}=\frac{K_1{K}_2{K}_{\mathrm{PWM}}}{\mathrm{sL}+R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Wherein, K ₁, K ₂be respectively used to the simplification coefficient representing voltage PI controller and current PI controller;

Equivalent time constant is:

$T=\frac{L}{R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Open-loop gain is:

k _o=K ₁K ₂K _PWM/(R+K ₂K _PWM[1-Kf(e)])。

Equipment provided by the invention, when not increasing hardware cost, can obtain good dynamic property by nonlinear Control.And implementation is simple, can increase the reliability of system.

The concrete simulated effect of present device is identical with embodiment of the method part, does not repeat them here.

The above is only preferred embodiment of the present invention, not does any pro forma restriction to the present invention.Although the present invention discloses as above with preferred embodiment, but and be not used to limit the present invention.Any those of ordinary skill in the art, do not departing under technical solution of the present invention ambit, the Method and Technology content of above-mentioned announcement all can be utilized to make many possible variations and modification to technical solution of the present invention, or be revised as the Equivalent embodiments of equivalent variations.Therefore, every content not departing from technical solution of the present invention, according to technical spirit of the present invention to any simple modification made for any of the above embodiments, equivalent variations and modification, all still belongs in the scope of technical solution of the present invention protection.

Claims (10)

1. a nonlinear control method for inverter, is characterized in that, comprises the following steps:

Obtain the deviation e of output voltage, the deviation e of described output voltage is given voltage reference value with inverter output voltage u _odifference;

When the deviation e of output voltage increases to positive direction, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point;

When the deviation e of output voltage increases to negative direction, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point.

2. the nonlinear control method of inverter according to claim 1, is characterized in that, also comprises:

If the absolute value of the deviation e of output voltage is less than the first preset value delta, then inverter inductance current inner loop feedback coefficient is constant.

3. the nonlinear control method of inverter according to claim 2, is characterized in that, described when the deviation e of output voltage increases to positive direction, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point; Be specially: if the absolute value of the deviation e of output voltage is more than or equal to described first preset value delta and is less than the second predetermined value a, then inverter inductance current inner loop feedback coefficient continues to be reduced to the first set point;

When the deviation e of output voltage increases to negative direction, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point, be specially: if the absolute value of the deviation e of output voltage is more than or equal to described second predetermined value a, then inverter inductance current inner loop feedback coefficient continues to increase to the second set point.

4. the nonlinear control method of inverter according to claim 3, is characterized in that, the inductive current i of described inductive current inner loop feedback " _lthe inductive current i exported with inductive current inner ring _lrelational expression be specially:

i" _L=i _L[1-Kf(e)]；

Wherein, described inductive current inner loop feedback coefficient is 1-Kf (e);

F (e) is a band dead band saturation nonlinearity function, $f\left(e\right)=\left\{\begin{array}{c}0,\left|e\right|<\mathrm{\&Delta;}\\ k(e-\mathrm{\&Delta;}),\mathrm{\&Delta;}\&le;\left|e\right|a\\ k(a-\mathrm{\&Delta;}),\left|e\right|\&GreaterEqual;a\end{array}\right.;$

Wherein, K and k is setting coefficient.

5. the nonlinear control method of the inverter according to any one of claim 1-4, is characterized in that, the deviation e and the inductive current inner ring sensing function that are obtained the output voltage of nonlinear Control by described inductive current inner loop feedback coefficient are:

$\frac{i_L}{e}=\frac{K_1{K}_2{K}_{\mathrm{PWM}}}{\mathrm{sL}+R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Wherein, K ₁, K ₂be respectively used to the simplification coefficient representing voltage PI controller and current PI controller;

Equivalent time constant is:

$T=\frac{L}{R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Open-loop gain is:

k ₀=K ₁K ₂K _PWM/(R+K ₂K _PWM[1-Kf(e)])。

6. a nonlinear Control equipment for inverter, is characterized in that, comprising: output voltage deviation obtains unit, deviation judging unit, feedback factor adjustment unit;

Described output voltage deviation obtains unit, for by given voltage reference value with inverter output voltage u _odifference obtain the deviation e of output voltage;

Described deviation judging unit, for judging that the deviation e of described output voltage increases to positive direction, or increases to negative direction;

Described feedback factor adjustment unit, when the deviation e of described output voltage increases to positive direction, for continuing to be reduced to the first set point by inverter inductance current inner loop feedback coefficient; When the deviation e of described output voltage increases to negative direction, for described inductive current inner loop feedback coefficient is continued to increase to the second set point.

7. the nonlinear Control equipment of inverter according to claim 6, is characterized in that, described deviation judging unit, also for judging whether the absolute value of the deviation e of described output voltage is less than the first preset value delta;

Described feedback factor adjustment unit, when the absolute value of the deviation e of described output voltage is less than the first preset value delta, for not adjusting described inductive current inner loop feedback coefficient.

8. the nonlinear Control equipment of inverter according to claim 6, is characterized in that, described deviation judging unit comprises: the first judgment sub-unit;

When described first judgment sub-unit judges that the absolute value of the deviation e of output voltage is more than or equal to described first preset value delta and is less than the second predetermined value a, then described inductive current inner loop feedback coefficient continues to be reduced to the first set point by feedback factor adjustment unit;

When described first judgment sub-unit judges that the absolute value of the deviation e of output voltage is more than or equal to described second predetermined value a, then described inductive current inner loop feedback coefficient continues to increase to the second set point by described feedback factor adjustment unit.

9. the nonlinear Control equipment of inverter according to claim 8, is characterized in that, the inductive current i of described inductive current inner loop feedback " _lthe inductive current i exported with inductive current inner ring _lrelational expression be specially:

i" _L=i _L[1-Kf(e)]；

Wherein, described inductive current inner loop feedback coefficient is 1-Kf (e);

F (e) is a band dead band saturation nonlinearity function, $f\left(e\right)=\left\{\begin{array}{c}0,\left|e\right|<\mathrm{\&Delta;}\\ k(e-\mathrm{\&Delta;}),\mathrm{\&Delta;}\&le;\left|e\right|a\\ k(a-\mathrm{\&Delta;}),\left|e\right|\&GreaterEqual;a\end{array}\right.;$

Wherein, K and k is setting coefficient.

10. the nonlinear Control equipment of inverter according to claim 9, is characterized in that, the deviation e and the inductive current inner ring sensing function that are obtained the output voltage of nonlinear Control by described inductive current inner loop feedback coefficient are:

$\frac{i_L}{e}=\frac{K_1{K}_2{K}_{\mathrm{PWM}}}{\mathrm{sL}+R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Wherein, K ₁, K ₂be respectively used to the simplification coefficient representing voltage PI controller and current PI controller;

Equivalent time constant is:

$T=\frac{L}{R+K_2{K}_{\mathrm{PWM}}[1-\mathrm{Kf}\left(e\right)]}$

Open-loop gain is:

k ₀=K ₁K ₂K _PWM/(R+K ₂K _PWM[1-Kf(e)])。