CN203482133U - IGBT type cascade speed regulation system - Google Patents

Abstract

The utility model discloses an IGBT type cascade speed regulation system. The circuit structure of the IGBT type cascade speed regulation system is that a motor rotor is connected with a diode uncontrollable rectifier to rectify alternating current into direct current; the diode uncontrollable rectifier matches rectification side direct current voltage with inversion side direct current voltage through a Boost chopper circuit to regulate the motor rotating speed; an inverter adopted by the inversion side is an IGBT fully controlled bridge to convert direct current into alternating current and feedback slip power to an electrical network; and finally the circuit structure is connected to a motor stator side through a transformer T1. The IGBT type cascade speed regulation system is simple in design method and strong in robustness of the control process, the power factor of the system can be effectively improved and the motor rotating speed regulation effect is good, and energy is saved.

Description

A kind of IGBT type cascade adjustable-speed system

Technical field

The utility model relates to the controller of Cascade Speed Regulation for AC Asynchronous Motor system inverter, belongs 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.

Utility model content

Defect for prior art, the utility model discloses a kind of IGBT type cascade adjustable-speed system, and for realizing control method and the control system 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 utility model, 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 utility model 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, 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.

Wherein, electric capacity and diode form the buffer circuit of Boost chopper circuit.

In the utility model, 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.

The utility model also provides for realizing the control system of above-mentioned functions, is connected to IGBT type cascade adjustable-speed system, acts on IGBT fully controlled bridge, and this control system comprises IGBT controller and circuit control device for copped wave.

Wherein, copped wave adopts speed and current double closed loop PI to control the control that realizes rotating speed with IGBT controller; Circuit control device is used for providing the drive control signal of inverter.

By above-mentioned control system, the control procedure strong robustness of the utility model governing system, 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 a, 2b are the additional schematic diagram that becomes structure control of IGBT cascade adjustable-speed system;

Fig. 3 is the method for designing flow chart of the utility model controller used thereby;

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

Specific implementation method

With reference to accompanying drawing 1, for the schematic diagram of the utility model IGBT type cascade adjustable-speed system, 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:

Voltage matches before and after chopper is closed:

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:

$n=n_0[1-(1-\frac{\mathrm{\τ}}{T})\frac{U_c}{2.34E_{r0}}]---\left(4\right)$

IGBT type cascade adjustable-speed system of the present utility model changes the size of duty ratio just can control the size of motor speed n, finally realizes energy-conservation object.

With reference to figure 2a, 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 a 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 with IGBT controller 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

pass through again the adjusting of PI link, realize the control of rotating speed.The controller 20 of inverter provides the drive control signal of inverter.

Wherein, the controller 20 of inverter is comprised of a plurality of hardware cells and circuit interface, provided as shown in Figure 2 b a kind of specific implementation of the control system 20 of inverter, comprise following unit: Mathematical Modeling construction unit 210, 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 in capacitor 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:

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

In formula, i _d, i _gfor d axle and the q axle component of AC three-phase current under dq coordinate, as the output variable of system; U _d, U _gfor d axle and the q axle component of transformer primary side three-phase voltage under dq coordinate; S _d, S _gfor 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 _g=0, now meritorious, reactive power P, the Q of system under dq coordinate system is:

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

From above formula, can be by controlling i _dand i _gcontrol 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 _g, U _dc], controlled quentity controlled variable is [u ₁, u ₂]=[S _d, S _g], output variable is [y ₁, y ₂]=[x ₁, x ₂]=[i _d, i _g], formula (6) can be changed into

$\left\{\begin{array}{c}{\stackrel{.}{x}}_1=(-{\mathrm{Rx}}_1+{\mathrm{L\ω}x}_2-U_d+u_1{x}_3)/L\\ {\stackrel{.}{x}}_2=(-{\mathrm{Rx}}_2-{\mathrm{L\ωx}}_1-U_g+u_2{x}_3)/L\\ {\stackrel{.}{x}}_3=[i_{\mathrm{dc}}-1.5(u_1{x}_1+u_2{x}_2)]/C\\ y_1=x_1\\ y_2=x_2\end{array}\right.---\left(8\right)$

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

$\left\{\begin{array}{c}{\stackrel{.}{y}}_1=({-\mathrm{Rx}}_1+\mathrm{L\ω}{x}_2-U_d+u_1{x}_3)/L\\ {\stackrel{.}{y}}_2=({-\mathrm{Rx}}_2-\mathrm{L\ω}{x}_1-U_g+u_2{x}_3)/L\end{array}\right.---\left(9\right)$

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:

$\left\{\begin{array}{c}{u}_1=\frac{1}{x_3}(U_d+{\mathrm{Rx}}_1-\mathrm{L\ω}{x}_2+L{\stackrel{.}{y}}_1)\\ u_2=\frac{1}{x_3}(U_g+{\mathrm{Rx}}_2+{\mathrm{L\ωx}}_1+L{\stackrel{.}{y}}_2)\end{array}\right.---\left(10\right)$

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 utility model 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:

$\left\{\begin{array}{c}{\stackrel{.}{x}}_1=v_1\\ {\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="DEST\_PATH\_HDA0000420541090000023.png"\; state="\{\{state\}\}">y</figure-callout>}}_1=x_1\end{array}\right.---\left(12\right)$

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

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 utility model 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

${\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="DEST\_PATH\_HDA0000420541090000023.png"\; state="\{\{state\}\}">s</figure-callout>}}_1=x_1-x_1^{+}---\left(14\right)$

Choose exponential approach rule, order

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

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

${\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="DEST\_PATH\_HDA0000420541090000023.png"\; state="\{\{state\}\}">v</figure-callout>}}_1=k_1(x_1^{+}-x_1)+{\mathrm{\&epsiv;}}_1\mathrm{sgn}(x_1^{+}-x_1)---\left(16\right)$

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,

$s_1{\stackrel{.}{s}}_1=-k_1{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="DEST\_PATH\_HDA0000420541090000023.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^2-{\mathrm{\&epsiv;}}_1{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="DEST\_PATH\_HDA0000420541090000023.png"\; state="\{\{state\}\}">s</figure-callout>}}_1\mathrm{sgn}\left(s_1\right)<0---\left(17\right)$

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

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:

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 utility model, formula (19) is the Mathematical Modeling form of presentation of the controller of the drawn IGBT type cascade adjustable-speed system inverter of the utility model method for designing.

Above-mentioned each unit all can be realized according to the disclosed formula of the utility model and Mathematical Modeling on the devices such as single-chip microcomputer, microcontroller, processor, and it is that those skilled in the art are very easy to realize that above-mentioned calculating process is realized on the computing units such as single-chip microcomputer, microcontroller, processor.

Claims (4)

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, 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 electric capacity and diode form the buffer circuit of Boost chopper circuit.

4. IGBT type cascade adjustable-speed system described in claim 1, is also connected with reactive compensation control system, comprises IGBT controller and circuit control device for copped wave.

Images