SU1585894A1 - Frequency-controllable electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used in systems of adjustable asynchronous electric drives of the textile industry and in other sectors. The aim of the invention is to improve the accuracy of regulation. This goal is achieved by introducing the EMF module calculation unit 21, the rotor current module calculating unit 22, the rotor current module calculating unit 23, the stator current modulus calculating unit 23, the voltage drop calculation on the stator and rotor inductive resistances, adders 26 - 28, the amplifier 29 and the unit 30 minimizing the angle between the EMF and the rotor current. In this case, the coordinate transformation is performed without multiplication operations and, in addition, the effect of feedback on EMF is compensated using a more accurate model 20 of the asynchronous motor, thereby improving the control accuracy. 2 Il.

Description

CPIJ2.1

The invention relates to electrical engineering, namely, automatic devices for controlling AC electric drives, and can be used in controlled asynchronous electric drive systems in the textile industry and in other sectors.

The purpose of the invention is to increase the exact HJocTH regulation,

I FIG. Figure 1 shows the functional scheme of the frequency-controlled e | pectropulse; FIG. 2 is a diagram of a mode | epi asynchronous motor; a variable-frequency electric drive (one contains an asynchronous motor 1 (| FIG, 1) with a short-circuited rotor, connected to the outputs of the inverter 2 Voltage, frequency control unit 3). and a voltage module with two inputs, the first of which is connected to the output of the unit 4 setting the voltage vector, and the output is connected to the control input of the voltage inverter 2, shaper 5 components of the voltage vector 1, sequentially connected Comparison element 6, one of the inputs of which is intended for supplying a flux link setting signal, flux linkage regulator 7, equation element 8, a stator current component regulator magnetizing the current component 9, connected in series to the intensity setpoint 10, the input of the reference frequency element 11, variable speed controller 12, dividing unit 13, comparator element 14, regulator 15 of the active component of the stator current, the output of which and the output of regulator 9 of the magnetizing component of the stator current are connected to the inputs of the former 5 voltages, also a voltage inverter model 16 connected by an input to the output of frequency control unit 3 and a voltage module, and an output to an input of converter 17 of the number of phases, unit 18 for calculating the flux coupler module, asynchronous model 20 for rotational speed motor, each phase of which is in a T-shaped replacement circuit, the variable-frequency drive module 21, the module for calculating the rotor current module, the block 23 for calculating the stator current module, blocks 24

and 25 calculating the voltage drop modules on inductive resistances of the stator and rotor dissipation of phase T-shaped replacement circuits, adders, amplifier 29 and unit 30 minimizing the angle between the EMF and the rotor current, the inputs of which are connected to the outputs of blocks 2 VI 22 calculating the EMF module and the rotor current module, and the output is connected to the second input (frequency control) of unit 3. At the same time, the outputs of the driver 5 were made up of voltage across the adders 26 and 27, respectively, connected to the inputs of the voltage vector setting unit 4. The other inputs of the adder 26 are connected respectively to the outputs of the EMC module 21 calculating unit and block 24. The input of the amplifier 29 is combined with another input of the divider unit 13 and connected to the output of the calculating unit 18 module of the flux linking module. The other input of the comparison element 11 is connected to the output of the rotational speed calculation unit 19 connected by the input with the model 20 moment output,

The model 20 asynchronous motor in each phase is completed in a T-shaped replacement circuit. Each model phase (FIG. 2) is composed of series-connected resistors 31, chokes 32 and 33, and resistor 34 in the first phase, resistor 35, chokes 36 and 37, and resistor 38. in the second phase, simulating the stator and inductors, respectively. and the rotor and forming the horizontal branch of the replacement scheme. In addition, phase replacement circuits include chokes 39 and 40, which simulate the mutual induction resistance, respectively. Model 20 also includes two integrators 41 and 42, multiplication elements 43 and 44, an inverting amplifier 45, and a block 46 for calculating the moment.

In this case, the inputs of the integrators 41 and 42 are connected respectively to the common points of connection of the resistor 34 and the throttles 33 of the first phase and the resistor 38 and the throttles 37 of the second phase. The output of the integrator 41 through the multiplication element 43 is connected to the free output of the resistor 38 of the second phase. The output of the integrator 42 through the inverting amplifier 45 and the multiplication element 44 is connected to the free output of the first phase resistor 34. Other inputs. The elements 43 and 44 multiplied are interconnected and connected to the output of the block.

51585894

19 calculate the rotational speed. The outputs of the integrators 41 and 42 are connected to the input-block-unit 18 of the module calculation. flux linking. The common points of resistors, pa 31 and droplets 32, resistors 35 and droplets 36, as well as the outputs of integrators 41 and 42 are connected to the inputs of the torque calculation unit 46 connected to the input of the unit 19. you have to calculate the rotation frequency.

The terminals of the resistors 39 and 40 are connected to the inputs of the unit 21 of the calculation of the emf module.

The terminals of the resistors 34 and 38 are connected to the inputs of the unit 22 for calculating the rotor current module. The common point of the resistor 35 and drossel 36 and the common point of resistor 31 and drossel 32 are connected to the input of the unit 23 for calculating the stator current component modules.

The outputs of series-connected chokes 32 and 33 in the first phase and / chokes 36 and 37 in the second phase are under, C, i; / R, +; - h i s total inductive

the stability of the stator and rotor; - active resistance

stator and rotor; magnetic factor

rotor coupling;

 - mutual inductance of stator and rotor windings.

The signals and (and, are further corrected for the purpose of complete uncoupling of the flux linkage control loops and the electromagnetic moment and are fed to the inputs of the unit for specifying the voltage vector

The signals of phase flux couplings j 20 Hjb of the outputs of the integrators 41 and 42 are fed to the inputs of the unit 18 for calculating the flux-linking module, the output of which is supplied as a ".-. G..". "" Feedback signal to the element

They are connected to the inputs of blocks 24 and 25, respectively-25 comparisons, as well as to the input of amplification,. 29,

The frequency-controlled electric unit 25 calculates the module (flU)

water works as follows, the voltage drops across the inductive signal of the reference (through the element of stator resistance and rotor 6 comparison is fed to the input of the regulator - 30 - second phase, realized by the linker 7 of the linkage, and 37 by expression

It simulates the transient process of establishing a given rotor flux linkage. At the output of the specified regulator 7, a task is generated to the controller 9 for the magnetizing component of the current, the stator.

Another setpoint signal from the intensity sensor 10 and the comparison element 11 is fed to the input of the rotational speed controller 12, the output of which, after dividing in block 13 by the flow coupling module, determines the reference for the active stator current controller 15.

The outputs of the regulators 9 and 15 u.i | til, uiips are fed to the inputs of format 5 and the voltage of the terminal, and the following is done:

35

40

45

   W, .L i | i, pl,

where OEc, is the frequency of rotation of the rotor current-coupled vector, lead; denoted by the number of pole pairs equal to unity. In block 24, the module luU Ip is calculated - the voltage across the inductive resistances of the stator and the rotor. the first phase, implemented using chokes 32 and 33, by the expression

U -VI 05t L; I i, |.

Ha output adder 26 receive (

and

R

 and + b5n1 - -E,

tde | E | - h EMF module, formed with the help of block 21, according to the signals Ej (, Ер,, we remove from the conclusions of the mutual induction resistance realized by the throttles 39 and 40,

1 iT

and

 9

duiji dt

where and / l, ul g,

-c7

H

and

F

- voltage at the outputs of block 5;

, C, i; / R, +; - h i s total inductive

the stability of the stator and rotor; - active resistance

stator and rotor; magnetic factor

rotor coupling;

 - mutual inductance of stator and rotor windings.

The signals and (and, are further corrected for the purpose of complete uncoupling of the flux linkage control loops and the electromagnetic moment and are fed to the inputs of the unit for specifying the voltage vector

The signals of the phase flux couplings j Hjb of the outputs of the integrators 41 and 42 are fed to the inputs of the block 18 for calculating the flux linkage module, the output of which is supplied as

   W, .L i | i, pl,

where OEc, is the frequency of rotation of the rotor current-coupled vector, lead; denoted by the number of pole pairs equal to unity. In block 24, the module luU Ip is calculated - the voltage across the inductive resistances of the stator and the rotor. the first phase, implemented using chokes 32 and 33, by the expression

U -VI 05t L; I i, |.

Ha output adder 26 receive (

and

R

 and + b5n1 - -E,

tde | E | - h EMF module, formed with the help of block 21, according to the signals Ej (, Ер,, we remove from the conclusions of the mutual induction resistance realized by the throttles 39 and 40,

IEI p „4ok | m / where p is the number of pairs of poles of the motor (JL) —the rotor speed.

At the output of the adder 27 get

w and ;, - "KL CR - -1 ,:

where KjR / / Lj is the conversion factor in the amplifier. 29 th Corrected signals,: correspond to the expressions:

C..i ,, C,

dt

Uw;

c, gS.

p,

TG2 P

where is ce. 1 / R- (+

In order to align the rotor flux vector, with the real axis of the coordinate system (), it is necessary to ensure a minimum angle between the emf and the rotor current, which is realized by the minimizing unit 30 of this angle. The inputs of the specified block, receives the current module of the rotor with | 5 block 22 and the EMF module from block 1. Block 30. It consists of a phase discriminator whose inputs receive signals TE) and, and an integrator whose output level is controlled by the key as a function of the angle between E and i

The output of block 30 is fed to the input of the frequency control of block 3, which causes an offset of the axes relative to the rotor.

Simultaneously, from the outputs of the adders 26, 27, the adjusted components of the stator voltage Ux, (and, where they are converted into a voltage module), (and) which is fed to the input of the control unit 3, enter the inputs of block 4. The output signal of block 3 is fed to an autonomous inverter 2 and on a voltage inverter model 16, representing a low-power analogue of the main inverter 2. An equivalent two-phase voltage system for powering the model 20 of an induction motor is obtained from the autonomous voltage inverter model 16, while the projections of the output voltage inverter y and U, g, on the motor C and B of the motor, stationary relative to the stator are represented in the 17 i converter of the three-phase voltage into the two-phase

five

0

5 0 5

0

five

0

five

as respectively the phase and linear voltages of a three-phase star-connected inverter load,

Model 20 of an asynchronous engine in a fixed coordinate system is described by a known system of differential equations, it works in real time, its output value is the torque of the engine, which is determined from the known relationship using block 46: And 1, (.

In this case, the current information is taken from the common point of the resistor 31 and droplets 32 in the first phase of the model, and the current information is taken from the common point of the resistor 35 and droplets 36 from the second phase of the model. Signals tiaLt C y. Come from the outputs of the integrators 41 and 42.

Since the task of determining the coordinates of the movement of the system is assigned to an analog model of the device, i.e. it performs the function of the observer and regulates the change in the frequency of rotation of the electric drive, the feedback on the frequency of rotation is implemented using the unit 19 for calculating the frequency of rotation. It consists of a transmission model and an actuator,. The first of which can be implemented using a T-reverse replacement circuit, with variable parameters of the vertical branch, taking into account the parameters of compliance and friction, and the second allows to take into account the change in load and moment of inertia and is a series-connected and separately adjustable inductance and resistor.

Thus, in the proposed h. The cost-adjustable electric drive performs coordinate transformations without multiplication operations and, in addition, compensates for the effect of feedback on EMF using a more accurate model of an asynchronous motor, thanks to the fact that the control accuracy is improved in comparison with the known solution.

Claims (1)

Invention Formula A variable frequency drive containing a squirrel cage rotor asynchronous motor connected to the outputs of the voltage inverter, a frequency control unit and a voltage module with two inputs, the first of which is connected to the output of the voltage vector setting unit and the output connected to the control input of the inverter the voltage, the driver of the components of the voltage vector, connected in series the first element of the comparison with the input for the signal of the task of the flow control, the flux linkage regulator, the second element of the comparison The regulator magnetizing component of the stator current, serially connected intensity setter with the input for the speed reference signal, the third comparison element the rotation frequency regulator dividing unit, the fourth comparison element, the active stator regulator of the stator current, the output of which the regulator output the magnetizing component of the stator current is connected to the shaper inputs of the voltage vector components, the voltage inverter model connected by the input to the output of the frequency control unit and the mode voltage, and output - to the input of the phase number converter, calculating units of the flux-linking module and rotation frequency, and the model of an asynchronous motor with two integrators, two multiplication elements, an inverting amplifier, and a torque calculating unit executed in each phase with T-obraz A replacement circuit, each phase of the model is made up of horizontal resistors and chokes in a horizontal branch, modeling, respectively, equivalent stator and stator resistances, inductive and act The actual resistance of the rotor, and in the vertical branch from the chokes, which model the resistance of mutual induction, the inputs of the integrators are connected respectively to the common connection points of the resistor and the chokes, which simulate the active and inductive resistances of the rotor in each phase of the T-shaped replacement circuit, the output the first integrator is connected to the free output of a resistor that simulates the rotor resistance in the second phase through the first multiplication element; the output of the second integrator is connected via an inverting amplifier of the second multiplying element with a free terminal of the resistor simulating ak0 five 0 five 0 five 0 five 0 five The rotor's primary resistance is in the first phase, the other inputs of the multiplication elements are combined and connected to the output of the rotation speed calculator connected to another input of the third comparator, the integrator outputs are connected to the inputs of the calculation module of the flux linkage module, the output of which is connected to another input of the first comparison element and with another input of the dividing unit, common points of resistors and chokes, simulating active and inductive resistance: the stator in each phase. T-shaped replacement circuit, and output The integrators are connected to the inputs of the torque calculation unit connected to the output of the rotation frequency calculation unit, characterized in that, in order to improve the control accuracy, the calculation blocks of the EMF module, the rotor current module, the stator current component modules, and the voltage drop modules are introduced inductive impedance of the scatter of the stator and rotor of fuzzy T-shaped replacement circuits, three adders, an amplifier and a unit for minimizing the angle between the emf and the current of the rotor, the inputs of which are connected to the outputs of the calculation units of the module The EMF and the rotor current module and the output are connected to the second input of the frequency control unit and the voltage module, while the outputs of the component voltages, respectively, through the first and second adders are connected to the inputs of the voltage vector setting unit, the other inputs of the first adder are connected to the outputs of the calculating unit — the EMF module and the calculating unit for dropping the voltage on the inductive resistance of the stator and rotor T-shaped replacement circuit of the first phase; another input of the second adder is connected to you the third adder connected by inputs to the output of the voltage drop calculating unit with inductive scattering stator and rotor of the T-shaped second-phase replacement circuit and to the output of the amplifier connected to the output of the slider of the flow coupling module simulating the resistance of mutual induction in each phase of the T-shaped replacement circuit, are connected to the inputs of the calculating unit of the EMF module, the terminals of the resistors simulating ac-: eleven 1585894 The effective rotor resistors in each phase of the T-shaped replacement circuit p are connected to the inputs of the calculating unit, the rotor current module, common resistor points and throttle points that simulate the stator active and inductive resistances of the first and second phases of the T-shaped replacement circuits components of the stator current, and conclusions after 12 inductively connected chokes simulating the inductive resistances of the stator and rotor in each phase of the T-shaped replacement circuit are connected to the inputs of the corresponding voltage drop calculator on the inductive resistances of the stator and rotor of the T-shaped phase replacement circuits. f /, M 1L i 40 Vpura fahg . hA FIG. I i - hV .-7 46 - .. f