CN103607161A - IGBT cascade speed regulation system, control method and control system thereof - Google Patents

Abstract

The invention discloses an IGBT type cascade speed regulation system. The circuit structure is that a motor rotor is connected with a diode uncontrollable rectifier, an alternating current is rectified into a direct current; the diode uncontrollable rectifier matches a rectifier side direct current voltage with an inverter side direct current voltage through a Boost chopper circuit, and regulates the rotation speed of the motor; an inverter used at the inverter side is an IGBT fully-controlled bridge, a direct current is converted into an alternating current, and slip power is fed back to a power grid; and finally the inverter side is connected to a motor stator side through a transformer T1. Correspondingly, the invention also discloses a reactive compensation control method and a control system of the abovementioned system, the robustness is strong, the system power factor can be effectively improved and regulation effects of the rotation speed of the motor are good, and energy and electricity are saved.

Description

A kind of IGBT type cascade adjustable-speed system and control method and control system

Technical field

The present invention relates to Cascade Speed Regulation for AC Asynchronous Motor system and control system thereof, belong to electrical machine energy-saving control field.

Background technology

The One's name is legion that blower fan and load of the pumps are applied in all kinds of industrial and mining enterprises, power consumption is huge, by cascade adjustable-speed system, reduces motor speed, to mate the rotating speed of blower fan and load of the pumps actual motion, can greatly reduce energy loss.

Common industrial cascade adjustable-speed system adopts thyristor inverter more at present, and after it puts into operation, power factor can reduce greatly.Analyze its reason and be that the rear active power of the rotating speed reduction of motor own can be less, and reactive power (lagging reactive power) is substantially constant; Diode rectifier and thyristor inverter are operated in respectively under uncontrollable rectification and phased inverting simultaneously, can consume huge reactive power, have caused waste of energy.

The industrial Cascade Speed Regulation Systems adopting with chopper more, the inversion angle of inverter is fixed on to the minimum value of permission, although the reactive power that can make inverter absorb from electrical network reduces to minimum degree, but do not change thyristor inverter bridge by the essence of the line voltage change of current, still exist phase place to lag behind, also just fundamentally do not solve the problem that power factor is low; Although also someone proposes to replace brake tube with IGBT in recent years, but its Theoretical Framework is complicated, and the control of inverter is adopted to vector PI type controller more, and controller parameter is difficult to adjust, and PI controller changes the inner parameter of inverter and external disturbance is comparatively responsive, poor robustness.

Summary of the invention

Defect for prior art, the invention discloses a kind of IGBT type cascade adjustable-speed system, and for realizing the control method of this controller, by adopt IGBT on hardware, modulation system adopts SPWM or SVPWM, when can realize inverter output amplitude and phase place, control, by internal compensation, solve the low problem of power factor.By control method of the present invention, controller strong robustness, when the generation disturbance of internal system parameter or while being subject to external disturbance, still can improve system power factor and motor speed regulating effect is good effectively.

For achieving the above object, the present invention is achieved through the following technical solutions:

An IGBT type cascade adjustable-speed system, circuit structure is: motor rotor connects the uncontrollable rectifier of diode, and AC rectification is become to direct current; The uncontrollable rectifier of diode is by Boost chopper circuit, and coupling rectification side direct voltage and inversion side direct voltage, regulate motor speed; The inverter that inversion side adopts is IGBT fully controlled bridge, by converting direct-current power into alternating-current power, slip power is fed back to electrical network; Finally, by transformer TI, be connected to motor stator side.

By said structure, the size that changes duty ratio just can be controlled the size of motor speed, finally realizes energy-conservation object.

For filtering high order harmonic component, IGBT fully controlled bridge is connected with inductance.

In the present invention, the adjusting of motor rotor rotating speed is closed and is

$n=n_0[1-(1-\frac{\mathrm{\τ}}{T})\frac{U_{\mathrm{dc}}}{2.34E_{r0}}]$

N wherein ₀for initial speed, U _dcfor DC capacitor voltage.

for the duty ratio of Boost chopper circuit, E _r0for motor rotor winding open circuit voltage.

In order to realize the feedback of slip power and the compensation of lagging reactive power, the invention provides the power-less compensation control method for above-mentioned IGBT type cascade adjustable-speed system, comprise the control of IGBT and the control of feedback inversion transformation device for copped wave.

Wherein copped wave adopts speed and current double closed loop PI to control with IGBT, and the output by the deviation of rotary speed instruction value and measured value after PI controller regulates, as the command value that flows out the direct current of rectifier, then passes through the adjusting of PI link, realizes the control of rotating speed.

Wherein, because the Mathematical Modeling of inverter is a System with Nonlinear Coupling, the control strategy that the present invention adopts method of inverse and Sliding mode variable structure control to combine to the control of inverter, this control method specifically comprises the steps:

1) set up the Mathematical Modeling of IGBT voltage source inverter under three phase static coordinate, set up Mathematical Modeling is carried out to Park conversion and obtain the Mathematical Modeling under dq0 coordinate system;

2) according to Mathematical Modeling, solve the inverse system of voltage source inverter, be connected on original system and form a pseudo-linear system before;

3) adopt exponential approach rule to design the sliding mode control law of above-mentioned pseudo-linear system, and this control law is applied to above-mentioned inverse system, the anti-controlled quentity controlled variable that solves original system;

4) input original system controlled quentity controlled variable, draws through Park inverse transformation and sinusoidal pulse width modulation (sinusoidal pulse width modulation, SPWM) and the drive control signal of inverter completes control.

Accordingly, the invention provides for realizing the control system of above-mentioned functions, be connected to IGBT type cascade adjustable-speed system, act on IGBT fully controlled bridge, this control system comprises IGBT controller and circuit control device for copped wave, and wherein copped wave adopts speed and current double closed loop PI to control the control that realizes rotating speed with IGBT controller; Wherein circuit control device comprises Mathematical Modeling construction unit, is used for building the Mathematical Modeling of inverter under dq coordinate system; Pseudo-linear system unit, for solving the inverse system of inverter Mathematical Modeling, and forms pseudo-linear system before being connected on original system; Become structure control unit, be used for designing the control law of inverter ac-side current component with the method for exponential approach rule, and be applied to the anti-controlled quentity controlled variable that solves original system of inverse system as output; Control signal output unit, is used for after original system control inputs amount it, through Park inverse transformation and sinusoidal pulse width modulation, drawing the drive control signal of inverter.

By above-mentioned control method and control system, the control procedure strong robustness of governing system of the present invention, can improve system power factor effectively and motor speed regulating effect is good.

Accompanying drawing explanation

Fig. 1 is the structured flowchart of IGBT type cascade adjustable-speed system;

Fig. 2 is the additional schematic diagram that becomes structure control of IGBT cascade adjustable-speed system;

Fig. 3 is the method for designing flow chart of controller used thereby of the present invention;

Fig. 4 is method of inverse Linearization Principle figure in the method for designing of controller used thereby of the present invention.

Specific implementation method

With reference to accompanying drawing 1, for the schematic diagram of IGBT type cascade adjustable-speed system of the present invention, wherein UR is the uncontrollable rectifier of diode, and intermediate module is Boost booster circuit, rear end is IGBT three-phase thyristor bridge inverter circuit, and contravariant transformer T1 draws telegram in reply machine stator side by energy.

Wherein inductance L plays filtering and energy storage, the pulsation of inhibition rotor current, reduces stator current higher harmonic components, and capacitor C forms the buffer circuit of chopper together with diode.

Wherein, the method for work of this governing system is as follows:

Motor rotor voltage:

u _r=sE _r0(1)

In formula, the revolutional slip that S is motor; E _r0for rotor winding open circuit voltage.

The output voltage of diode rectifier bridge is:

U _DR=2.34sE _r0(2)

Voltage matches before and after chopper is closed:

$U_{\mathrm{DR}}=(1-\frac{\mathrm{\τ}}{T})U_{\mathrm{dc}}---\left(3\right)$

In formula, U _dcfor DC capacitor voltage.

duty ratio for chopper circuit.

By speed control principle and formula (3), (4), can obtain rotating speed formula and be:

$n=n_0[1-(1-\frac{\mathrm{\τ}}{T})\frac{U_{\mathrm{dc}}}{2.34E_{r0}}]$

IGBT type cascade adjustable-speed system of the present invention changes the size of duty ratio just can control the size of motor speed n, finally realizes energy-conservation object.The Boost chopper circuit of foregoing circuit is just in time contrary with traditional B oost circuit, is a reverse procedure.

With reference to figure 2, be the control principle of IGBT type cascade adjustable-speed system, Fig. 2 top is tandem control pie graph: the uncontrollable rectifier UR of diode connects motor rotor, and AC rectification is become to direct current; Then pass through Boost chopper circuit, by control, account for copped wave with the opening, turn-off of IGBT, mate rectification side direct voltage and inversion side direct voltage, realize the object that regulates motor speed; What inverter adopted is IGBT fully controlled bridge, by converting direct-current power into alternating-current power, slip power is fed back to electrical network, realizes energy-conservation object, and the inductance L connecing after inverter plays filtering high order harmonic component, and R is equivalent loss resistance; Finally, by transformer TI, be connected to stator side.

Fig. 2 below is the control system block diagram of IGBT type cascade adjustable-speed system, and wherein copped wave adopts speed and current double closed loop PI to control by IGBT control system 10, rotary speed instruction value n ^*with the output after PI controller regulates of the deviation of measured value n, as the direct current i that flows out rectifier _dccommand value i ^* _dc, then pass through the adjusting of PI link, realize the control of rotating speed.

By reference to the accompanying drawings 3 and 2, the control system 20 of inverter comprises following unit: Mathematical Modeling construction unit 210, and as shown in step 101,102 in Fig. 3, the Mathematical Modeling of these Mathematical Modeling construction unit 210 model inverters under three phase static coordinate system:

$\left\{\begin{array}{c}{\mathrm{Ldi}}_a/\mathrm{dt}=S_a{U}_{\mathrm{dc}}-{\mathrm{Ri}}_a-U_a\\ {\mathrm{Ldi}}_b/\mathrm{dt}=S_b{U}_{\mathrm{dc}}-{\mathrm{Ri}}_b-U_b\\ {\mathrm{Ldi}}_c/\mathrm{dt}=S_c{U}_{\mathrm{dc}}-{\mathrm{Ri}}_c-U_c\\ {\mathrm{CdU}}_{\mathrm{dc}}/\mathrm{dt}=i_{\mathrm{dc}}-(S_a{i}_a+S_b{i}_b+S_c{i}_c)\end{array}\right.---\left(5\right)$

In formula, U _a, U _b, U _cfor the former limit of contravariant transformer three-phase voltage, i _a, i _b, i _cfor flowing out the three-phase current of inverter, L, R are respectively filter inductance and the equivalent loss resistance of AC, and c is DC bus capacitor, U _dcfor the voltage on electric capacity c, S _a, S _b, S _cbe respectively the pulse triggering signal of the turn-off device of three-phase inverter, i _dcfor flowing into the DC side electric current of electric capacity and inverter.Then Mathematical Modeling being carried out to Park by three phase static coordinate transforms under dq0 coordinate system:

$\left\{\begin{array}{c}L\frac{{\mathrm{di}}_d}{\mathrm{dt}}=S_d{U}_{\mathrm{dc}}-{\mathrm{Ri}}_d+\mathrm{\ω}{\mathrm{Li}}_q-U_d\\ L\frac{{\mathrm{di}}_q}{\mathrm{dt}}=S_q{U}_{\mathrm{dc}}-{\mathrm{Ri}}_q-\mathrm{\ω}{\mathrm{Li}}_d-U_q\\ C\frac{{\mathrm{dU}}_{\mathrm{dc}}}{\mathrm{dt}}=i_{\mathrm{dc}}-\frac{3}{2}(S_d{i}_d+S_q{i}_q)\end{array}\right.---\left(6\right)$

In formula, i _d, i _qfor d axle and the q axle component of AC three-phase current under dq coordinate, as the output variable of system; U _d, U _qfor d axle and the q axle component of transformer primary side three-phase voltage under dq coordinate; S _d, S _qfor d axle and the q axle component of switch function under dq coordinate, as the input variable of system; ω is system angle frequency.

When the initial phase angle of Park conversion is identical with busbar voltage initial phase angle, there is U _q=0, now meritorious, reactive power P, the Q of system under dq coordinate system is:

$\left\{\begin{array}{c}P=\frac{3}{2}{U}_d{i}_d\\ Q=\frac{3}{2}{U}_d{i}_q\end{array}\right.---\left(7\right)$

From above formula, can be by controlling i _dand i _qcontrol separately active power and reactive power.

Shown in Fig. 3 step 103, pseudo-linear system unit 220 solves the inverse system of inverter Mathematical Modeling, the Mathematical Modeling for the inverter of formula (6) under dq coordinate system, and state variable is [x ₁, x ₂, x ₃]=[i _d, i _q, U _dc], controlled quentity controlled variable is [u ₁, u ₂]=[S _d, S _q], output variable is [y ₁, y ₂]=[x ₁, x ₂]=[i _d, i _q], formula (6) can be changed into

$\left\{\begin{array}{c}{\stackrel{\&CenterDot;}{x}}_1=(-{\mathrm{Rx}}_1+{\mathrm{L\&omega;x}}_2-U_d+u_1{x}_3)/L\\ {\stackrel{\&CenterDot;}{x}}_2=(-{\mathrm{Rx}}_2-{\mathrm{L\&omega;x}}_1-U_q+u_2{x}_3)/L\\ {\stackrel{\&CenterDot;}{x}}_3=[i_{\mathrm{dc}}-1.5(u_1{x}_1+u_2{x}_2)]/\mathrm{<figure-callout\; id="1"\; label="C\; y"\; filenames="HDA00003651803800022.png"\; state="\{\{state\}\}">C</figure-callout>}& \\ y_{}{}_1=x_1\\ y_2=x_2\end{array}\right.---\left(8\right)$

Output equation to formula (8) asks first derivative to obtain:

$\left\{\begin{array}{c}{\stackrel{\&CenterDot;}{y}}_1=(-{\mathrm{Rx}}_1+{\mathrm{L\&omega;x}}_2-U_d+u_1{x}_3)/L\\ {\stackrel{\&CenterDot;}{y}}_2=(-R{x}_2-L{\mathrm{\&omega;x}}_1-U_q+u_2{x}_3)/L\end{array}\right.---\left(9\right)$

From above formula, aobvious containing input variable in the first derivative of output equation, the inverse system equation that can try to achieve formula (6) is:

$\left\{\begin{array}{c}{u}_1=\frac{1}{x_3}(U_d+{\mathrm{Rx}}_1-{\mathrm{L\&omega;x}}_2+L{\stackrel{\&CenterDot;}{y}}_1)\\ u_2=\frac{1}{x_3}(U_q+{\mathrm{Rx}}_2+L{\mathrm{\&omega;x}}_2+{\mathrm{L\&omega;x}}_1+L{\stackrel{\&CenterDot;}{y}}_2)\end{array}\right.---\left(10\right)$

Order

for the new input variable of inverse system, before inverse system formula (10) is connected on to original system, as shown in Figure 4.From input/output relation, can find out, inverse system formula (10) has compensated original system formula (8) for the pseudo-linear system that has the decoupling zero of linear transitive relation into.

According to inverse system relative rank definition, and convolution (9), the phase match exponents of trying to achieve above-mentioned inverse system is:

α=(α ₁，α ₂)=(1，1)=2 (11)

Because the exponent number of original system is 3, be greater than the phase match exponents 2 of inverse system, illustrate in pseudo-linear system, exist one hidden dynamically, i.e. the 3rd expression formula in equation (8), the stability problem of DC capacitor voltage.The present invention adopts PI controller to realize the stable of capacitance voltage.

With reference to figure 4, the independently linearisation subsystem that pseudo-linear system is decoupled into can be expressed as:

$\left\{\begin{array}{c}{\stackrel{\&CenterDot;}{x}}_1=v_1\\ {\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="HDA00003651803800022.png"\; state="\{\{state\}\}">y</figure-callout>}}_1=x_1\end{array}\right.---\left(12\right)$

$\left\{\begin{array}{c}{\stackrel{\&CenterDot;}{x}}_2=v_2\\ y_2=x_2\end{array}\right.---\left(13\right)$

In conjunction with in Fig. 3 shown in step 104, become the control law of the method design inverter AC dq shaft current component of structure control unit 230 based on sliding mode control theory Exponential Reaching Law: the present invention is from eliminating internal system parameter perturbation, the angle that strengthens controller robustness is set out, and uses the method for sliding mode control theory Exponential Reaching Law to design its controller.For subsystem formula (12), the design object of controller is:

by DC capacitor voltage U _dccommand voltage given with it

the output conduct of deviation after pi regulator regulates

Getting sliding-mode surface is

${\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="HDA00003651803800022.png"\; state="\{\{state\}\}">s</figure-callout>}}_1=x_1-x_1^{*}---\left(14\right)$

Choose exponential approach rule, order

${\stackrel{\&CenterDot;}{s}}_1=-k_1{s}_1-{\mathrm{\&epsiv;}}_1\mathrm{sgn}\left(s_1\right)---\left(15\right)$

The sliding mode control law that solves subsystem formula (12) is

${\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="HDA00003651803800022.png"\; state="\{\{state\}\}">v</figure-callout>}}_1=k_1(x_1^{*}-x_1)+{\mathrm{\&epsiv;}}_1\mathrm{sgn}(x_1^{*}-x_1)---\left(16\right)$

In formula (12): sgn (s ₁) be sign function; k ₁, ε ₁for Sliding mode variable structure control parameter, k ₁>0, ε ₁>0, s ₁sgn (s ₁) >0,

$s_1{\stackrel{\&CenterDot;}{s}}_1=-k_1{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="HDA00003651803800022.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^2-{\mathrm{\&epsiv;}}_1{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="HDA00003651803800022.png"\; state="\{\{state\}\}">s</figure-callout>}}_1\mathrm{sgn}\left(s_1\right)<0---\left(17\right)$

From formula (13), the control inputs amount of subsystem formula (12) meets the arrival condition of sliding-mode surface, therefore designed control law can be realized the timely tracking of controlling target,

in formula (12), suitably increase k ₁value can improve the velocity of approach that sliding formwork is controlled, and suitably reduces ε ₁value can weaken the buffeting that sliding formwork is controlled.

Design object for subsystem formula (13) controller is:

from the second formula of formula (7), can calculate (Q ^*compensation rate for given reactive power).The same, the sliding mode control law that can design subsystem formula (13) is:

$v_2=k_2(x_2^{*}-x_2)+{\mathrm{\&epsiv;}}_2\mathrm{sgn}(x_2^{*}-x_2)---\left(18\right)$

In conjunction with in Fig. 3 shown in step 105, the result substitution formula (10) of formula (16), (18) gained can be solved to original system control inputs amount u ₁, u ₂expression formula as follows:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="u"\; filenames="HDA00003651803800022.png"\; state="\{\{state\}\}">u</figure-callout>}}_1=\frac{1}{x_3}\{U_d+{\mathrm{Rx}}_1-\mathrm{\&omega;}{\mathrm{Lx}}_2+L[k_1(x_1^{*}-x_1)+{\mathrm{\&epsiv;}}_1\mathrm{sgn}(x_1^{*}-x_1)\left]\right\}\\ u_2=\frac{1}{x_3}\{U_q+{\mathrm{Rx}}_2+\mathrm{\&omega;}{\mathrm{<figure-callout\; id="1"\; label="Lx"\; filenames="HDA00003651803800022.png"\; state="\{\{state\}\}">Lx</figure-callout>}}_1+L[k_2(x_2^{*}-x_2)+{\mathrm{\&epsiv;}}_1\mathrm{sgn}(x_2^{*}-x_2)\left]\right\}\end{array}\right.---\left(19\right)$

Try to achieve original system control inputs amount u ₁, u ₂after, by it through Park inverse transformation and SPWM sinusoidal pulse width modulation,

Draw the drive control signal of inverter, as shown in step 106 in Fig. 3, thereby the effective reactive power of control and compensation and realize the stable of capacitance voltage improves the power factor of whole system.

Be more than implementation method of the present invention, formula (19) is the Mathematical Modeling form of presentation of the controller of the drawn IGBT type cascade adjustable-speed system inverter of method for designing of the present invention.

Claims (6)

1. an IGBT type cascade adjustable-speed system, its circuit structure is: motor rotor connects the uncontrollable rectifier of diode, and AC rectification is become to direct current; The uncontrollable rectifier of diode is by Boost chopper circuit, and coupling rectification side direct voltage and inversion side direct voltage, regulate motor speed; The inverter that inversion side adopts is IGBT fully controlled bridge, by converting direct-current power into alternating-current power, slip power is fed back to electrical network; Finally, by transformer TI, be connected to motor stator side.

2. IGBT type cascade adjustable-speed system according to claim 1, is characterized in that IGBT fully controlled bridge is connected with inductance, filtering high order harmonic component.

3. IGBT type cascade adjustable-speed system according to claim 1, is characterized in that the adjusting pass of motor rotor rotating speed is n wherein ₀for initial speed, U _dcfor DC capacitor voltage.

for the duty ratio of Boost chopper circuit, E _r0for motor rotor winding open circuit voltage.

4. the power-less compensation control method of IGBT type cascade adjustable-speed system described in claim 1, it is characterized in that comprising that copped wave adopts speed and current double closed loop PI to control with IGBT, output by the deviation of rotary speed instruction value and measured value after PI controller regulates, as the command value that flows out the direct current of rectifier, pass through again the adjusting of PI link, realize the control of rotating speed.

5. the power-less compensation control method of IGBT type cascade adjustable-speed system described in claim 1, is characterized in that comprising the steps: the control strategy that adopts method of inverse and Sliding mode variable structure control to combine to the control of inverter

1) Mathematical Modeling of the inverter of model inversion side under three phase static coordinate system, and above-mentioned Mathematical Modeling Park is transformed to dq0 coordinate system;

2) solve the inverse system of inverter Mathematical Modeling, inverse system is connected in series to original system, compensate into the pseudo-linear system of the decoupling zero with linear transitive relation;

3) adopt the method design sliding mode control law of exponential approach rule, this control law is applied to pseudo-linear system and obtains original system controlled quentity controlled variable;

4) input original system controlled quentity controlled variable, through Park inverse transformation and sinusoidal pulse width modulation, draws the drive control signal of inverter by it.

6. IGBT type cascade adjustable-speed system described in claim 1, also be connected with reactive compensation control system, comprise IGBT controller and circuit control device for copped wave, wherein circuit control device comprises Mathematical Modeling construction unit, is used for building the Mathematical Modeling of inverter under dq coordinate system; Pseudo-linear system unit, for solving the inverse system of inverter Mathematical Modeling, and forms pseudo-linear system before being connected on original system; Become structure control unit, be used for designing the control law of inverter ac-side current component with the method for exponential approach rule, and be applied to the anti-controlled quentity controlled variable that solves original system of inverse system as output; Control signal output unit, is used for after original system control inputs amount it, through Park inverse transformation and sinusoidal pulse width modulation, drawing the drive control signal of inverter.

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