CN103795319A - AC motor revolving speed tracking method, speed control device and AC motor - Google Patents

Abstract

The invention discloses an AC motor revolving speed tracking method which is used to track a revolving speed when an AC motor restarts. The method includes the following steps: 1, a current flux linkage angle is estimated; 2, a stator current vector carries out coordinate conversion so as to obtain a first current value and a second current value which are respectively in line with and perpendicular to the flux linkage angle; 3, the first current value and a preset non-zero current values serve as input, and through calculation of a current regulator, a voltage is obtained (img file = 'dest_path_image002. TIF' wi = '24' he = '16'/); the second current value and 0 serve as input, and through calculation of the current regulator, a voltage is obtained (img file = 'dest_path_image004. TIF' wi = '16' he = '16'/); 4, voltages (img file ='891979dest_path_image002. TIF' wi = '24' he = '16' /) and (img file ='996071dest_path_image004. TIF' wi ' = '16' he = '16' /) carry out pulse width modulation to generate a driving control signal to drive the AC motor; and 5, steps from 1 to 4 are repeated, until the second current value is lower than a current threshold value and maintains for a period of a preset time, and differential calculation of a current flux angle is carried out to get the revolving speed when the AC motor restarts. The invention also discloses an AC motor speed control device and the AC motor. According to the invention, the advantages of being fast, accurate and low-cost are realized.

Description

A kind of rotating-speed tracking method, speed regulating device and alternating current machine of alternating current machine

Technical field

The rotating-speed tracking method, speed regulating device and the alternating current machine that the present invention relates to a kind of alternating current machine, belong to alternating current machine technical field.

Background technology

Because complexity and the technological requirement at industrial applicability scene are various, the performance requirement while having determined frequency conversion speed-adjusting system except normal operation, also requiring to possess has enough disposal abilities to irregular operating state.As: large-scale ventilation equipment freely reverse because the remaining air quantity in air channel may cause motor, and large inertia load runs into after unexpected power failure, and motor can rotate freely considerable time, is dozens of minutes; If now direct starter motor, can may make to start unsuccessfully (overcurrent protection) in the slip state compared with large because of motor.In order to prevent this phenomenon, after service restoration is normal, require the governing system of motor to possess alternating current machine rotating-speed tracking restart function.

(application number is 201110077358.0 to one piece of Chinese patent literature, within open day, be 2012-09-26) a kind of rotating-speed tracking method of induction motor disclosed, it is to the effect that: be more than or equal to setting DC bus voltage when DC bus voltage error judgment module judges this detection DC bus voltage, or in the time that current error judge module judges that feedback current is less than or equal to setting electric current, DC bus voltage error judgment module or current error judge module send a switch controlling signal this control end to switch, first control signal to this voltage modulation module to allow switch transmit this, this voltage modulation module is received control inverter driven induction motor after this first control signal, otherwise this frequency searching module transmits this and second controls signal to voltage modulation module, so that this this inverter of voltage modulation module controls changes the stator field frequency of this induction motor, and again carry out the judgement of aforementioned DC bus voltage error judgment module and this current error judge module.

Again, in the document, also record following content: the Speed search device that a kind of induction motor is provided, it is by a DC bus voltage, the error judgment module output current judge module of arranging in pairs or groups, judge whether that the rotor field frequency of induction motor is more than or equal to the output voltage frequency of frequency converter, that is the rotor frequency that whether has induction motor is more than or equal to the stator field frequency situation generation of induction motor, allow whereby Speed search device can find out induction motor rotating speed at that time, and rotating speed starts the switch element switching running of control inverter thus, so can improve the success rate that searches induction motor rotating speed.

There is following problem in the technical scheme of recording in above-mentioned document: 1) the definite of the first control signal is more very difficult, if arrange improperly, probably can cause the generation of overcurrent or overvoltage phenomenon of the failure.2), if the stator field frequency of current search and induction motor actual speed gap are large, especially when stator field frequency and induction motor actual speed opposite direction, so, the search time of Speed search device can be long.Therefore, this scheme has some limitations in practice.

Summary of the invention

Technical problem to be solved by this invention is to overcome prior art deficiency, a kind of rotating-speed tracking method, speed regulating device and alternating current machine of alternating current machine are provided, rotating speed size and Orientation can estimate fast and effectively alternating current motor and restart time, and then realize the steady restart function of motor.

The present invention specifically solves the problems of the technologies described above by the following technical solutions:

A rotating-speed tracking method for alternating current machine, the rotating speed while restarting for following the tracks of alternating current machine, described rotating-speed tracking method comprises:

When step 1, alternating current machine are restarted, first estimate the current magnetic linkage angle of described alternating current machine;

Step 2, the stator current vector of described alternating current machine is carried out to coordinate transform, obtains respectively first current value identical with estimated magnetic linkage angle direction, and one with orthogonal the second current value of estimated magnetic linkage angle direction;

Step 3, using the predetermined current value of the first current value and a non-zero as input, obtain a voltage u through automatic current regulator computing _m; Using the second current value and 0 as input, obtain a voltage u through automatic current regulator computing _t;

Step 4, with voltage u _mand u _tas input, utilize pulse-width modulation to generate drive control signal and drive described alternating current machine;

Step 5, repeated execution of steps 1～step 4, until described the second current value is lower than default current threshold and maintain one default period; The magnetic linkage angle that described alternating current machine is current is differentiated, the rotating speed when obtaining described alternating current machine and restarting.

Speed regulating device for alternating current machine, comprising: PWM module, inverter module and voltage reconstructed module; Described PWM module is modulated to the voltage signal of input the control signal of inverter module, and described inverter module drives described alternating current machine according to the control signal of PWM module output, and described voltage reconstructed module is used for calculating stator voltage vector; Described speed regulating device also comprise rotating speed search module, and described rotating speed search module comprises coordinate transformation module, the first current regulator, the second current regulator, magnetic linkage angle estimation device and differential module; In the time that described alternating current machine is restarted, magnetic linkage angle estimation device first estimates the current magnetic linkage angle of described alternating current machine, and by the current magnetic linkage angle input coordinate conversion module estimating; Coordinate transformation module carries out coordinate transform to the stator current vector of described alternating current machine, obtain respectively first current value identical with estimated magnetic linkage angle direction, and one with orthogonal the second current value of estimated magnetic linkage angle direction, and the first current value and the second current value are inputted respectively to the first current regulator, the second current regulator; The first current regulator is using the predetermined current value of the first current value and a non-zero as input, and computing obtains a voltage u _m; The second current regulator is using the second current value and 0 as input, and computing obtains a voltage u _t; Described PWM module is with voltage u _mand u _tas input, the control signal that generates inverter module drives described alternating current machine; When described the second current value is lower than default current threshold and maintain one section of default time t, the current magnetic linkage angle that described differential module estimates magnetic linkage angle estimation device is differentiated, the rotating speed when obtaining described alternating current machine and restarting.

In technical scheme of the present invention, described magnetic linkage angle can be stator magnetic linkage angle, can be also rotor flux angle, can utilize existingly maybe the various Flux Observation Model/computational methods that have to be obtained the preferably following three kinds of schemes of the present invention:

The first preferred version: the stator magnetic linkage angle that described magnetic linkage angle is described alternating current machine, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{{\mathrm{\ψ}}_{\mathrm{s\α}}}\right)$

In formula,

for estimated stator magnetic linkage angle; ψ _{s α}, ψ _{s β}be respectively stator magnetic linkage vector under alpha-beta two-phase static coordinate

at the component of α, β direction, obtain according to following formula:

Wherein,

with

be respectively the stator voltage vector stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance.

The second preferred version: the rotor flux angle that described magnetic linkage angle is described alternating current machine, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{r\β}}}{{\mathrm{\ψ}}_{\mathrm{r\α}}}\right)$

In formula,

for estimated rotor flux angle; ψ _{r α}, ψ _{r β}be respectively alpha-beta two-phase static coordinate lower rotor part flux linkage vector

at the component of α, β direction, obtain according to following formula:

Wherein,

with

be respectively the stator voltage vector stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance,

l _mfor alternating current machine mutual inductance, L _rfor AC motor rotor inductance, L _sfor alternating-current motor stator self-induction.

The third preferred version: described magnetic linkage angle is described alternating current machine without stator resistance magnetic linkage angle, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{{\mathrm{\ψ}}_{\mathrm{s\α}}}\right)$

In formula,

for estimated without stator resistance magnetic linkage angle; ψ _{s α}, ψ _{s β}be respectively under alpha-beta two-phase static coordinate without stator resistance flux linkage vector

at the component of α, β direction,

obtain according to following formula:

Wherein,

for the stator voltage vector of described alternating current machine.

Further, described rotating speed search module also comprises filtration module, and its input is connected with the output of described differential module; Utilize filtration module to process the rotating speed of differential module output, can obtain motor more stably and restart rotating speed.

According to invention thinking of the present invention, also can obtain a kind of alternating current machine, comprise speed regulating device described in above any one; Thereby can fast and effeciently estimate the rotating speed size and Orientation while restarting, and then realize restart function stably.

Compared to existing technology, the present invention has following beneficial effect:

One, in technical solution of the present invention, alternating current machine rotating speed size is synchronizeed estimation with direction, and rotating speed is short and controlled search time;

Two, the present invention is based on size and the direction of rotating speed search module estimation alternating current machine rotating speed, can estimated speed scope extensively, easily realize and compatible strong;

Three, the present invention can realize based on existing device and circuit, without the pressure of hardware cost aspect.

Accompanying drawing explanation

Fig. 1 is the system configuration schematic diagram of alternating current machine of the present invention.

Embodiment

Below in conjunction with accompanying drawing, technical scheme of the present invention is elaborated:

Fig. 1 has shown the structured flowchart of an embodiment of alternating current machine of the present invention, as shown in the figure, alternating current machine of the present invention comprises alternating current motor and speed regulating device, speed regulating device comprise: PWM module, inverter module and voltage reconstructed module, PWM module is modulated to the voltage signal of input the input control signal of inverter module, inverter module drives alternating current motor according to the control signal of PWM module output, and voltage reconstructed module calculates stator voltage vector by the control signal that gathers busbar voltage Udc and the output of PWM module

as shown in the figure, speed regulating device of the present invention also comprise rotating speed search module (as shown in dotted line frame part in figure), this rotating speed search module comprises: coordinate transformation module, the first current regulator ACR_M, the second current regulator ACR_T, magnetic linkage angle estimation device G and differential module D, at the input of PWM module, the first switch S 1 and second switch S2 are set, the input a end of the first switch S 1 connects VF(Variable-frequency, frequency conversion) output of control unit, the input b end of the first switch S 1 connects the output of the second current regulator ACR_T, the input a end of second switch S2 connects the output of VF control unit, the input b end of second switch S2 connects the output of the first current regulator ACR_M, in the time that speed regulating device normally move, switch S 1 is connected with a end separately with S2, VF control unit receiving frequency signals ω output voltage signal are to PWM module, PWM module is modulated to the voltage signal of input the input control signal of inverter module, described inverter module is controlled output power to alternating current motor according to the output control signal of PWM module, while starting again after RHVC shuts down, need to follow the tracks of the rotating speed of alternating current motor, the first switch S 1 and second switch S2 are switched to b end separately by PWM module.

In the time carrying out rotating-speed tracking, first by the stator current vector of current sample device sampling alternating current motor

calculate stator voltage vector by voltage reconstructed module according to the control signal of busbar voltage Udc and the output of PWM module simultaneously

and will

with

input magnetic linkage angle estimation device G; Estimate the angle of current magnetic linkage and by the angle of the current magnetic linkage estimating

input to coordinate transformation module; Stator current vector

in conjunction with the angle of current magnetic linkage

through coordinate transformation module (in the present embodiment for Clark and Park coordinate conversion) transform operation go out one with

current value i on equidirectional _mwith another with

the current value i that direction is orthogonal _t; The first current regulator ACR_M is by the non-zero current value of a setting

with i _mas input, calculate an input variable u of PWM module _m, the second current regulator ACR_T is by set point 0 and i _tas input, calculate an input variable u of PWM module _t(the first and second current regulators are identical); PWM module is by the voltage signal u of input _m, u _tbe modulated to the input control signal of inverter module, inverter module drives alternating current motor according to the output control signal of PWM module; Repeat said process, until with

the current value i that direction is orthogonal _tleveling off to 0(can be by relatively judging with a predefined current threshold of 0 of leveling off to), and maintain after one section of default time t, by the angle of the magnetic linkage obtaining

after differential module D computing, obtain output variable

be the rotating speed of required alternating current motor; Further, output variable

can obtain through filtration module LP computing

obtain alternating current motor rotating speed more stably; Finally the first switch S 1 and second switch S2 are connected to a end separately, by the rotating speed obtaining

as the input of VF control unit, thereby two of outputs are controlled voltages and are input to PWM module and carry out control inverter module and follow the tracks of and control the operation of motor.

Stator voltage vector in the present embodiment, the calculating of stator current vector, the calculating of magnetic linkage angle, and current regulator, PWM module, coordinate transformation module etc. all can adopt existing mature technology.The present invention preferably adopts stator magnetic linkage angle, rotor flux angle and without these three kinds of magnetic linkage angles of stator resistance magnetic linkage angle, the evaluation method of three kinds of magnetic linkage angles is as follows respectively:

(1) the stator magnetic linkage angle that the magnetic linkage angle of described magnetic linkage angle estimation device output is described alternating current machine, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{{\mathrm{\ψ}}_{\mathrm{s\α}}}\right)$

In formula,

for estimated stator magnetic linkage angle; ψ _{s α}, ψ _{s β}be respectively stator magnetic linkage vector under alpha-beta two-phase static coordinate at the component of α, β direction, obtain according to following formula:

Wherein,

with

be respectively the stator voltage vector stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance.Wherein, stator resistance R _scan pass through a given d. c. voltage signal U, sampling alternating current motor output current I, then by formula R _s=U/I computing is obtained.

(2) the rotor flux angle that the magnetic linkage angle of described magnetic linkage angle estimation device output is described alternating current machine, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{r\β}}}{{\mathrm{\ψ}}_{\mathrm{r\α}}}\right)$

In formula, for estimated rotor flux angle; ψ _{r α}, ψ _{r β}be respectively alpha-beta two-phase static coordinate lower rotor part flux linkage vector

at the component of α, β direction,

obtain according to following formula:

Wherein,

with

be respectively the stator voltage vector stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance,

l _mfor alternating current machine mutual inductance, L _rfor AC motor rotor inductance, L _sfor alternating-current motor stator self-induction.L _m, L _r, L _sbe the intrinsic parameter of alternating current machine, can pre-enter magnetic linkage angle estimation device.

(3) the magnetic linkage angle of described magnetic linkage angle estimation device output is described alternating current machine without stator resistance magnetic linkage angle, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{{\mathrm{\ψ}}_{\mathrm{s\α}}}\right)$

In formula,

for estimated without stator resistance magnetic linkage angle; ψ _{s α}, ψ _{s β}be respectively under alpha-beta two-phase static coordinate without stator resistance flux linkage vector

at the component of α, β direction, obtain according to following formula:

Wherein,

for the stator voltage vector of described alternating current machine.

Claims (10)

1. a rotating-speed tracking method for alternating current machine, the rotating speed while restarting for following the tracks of alternating current machine, is characterized in that, described rotating-speed tracking method comprises:

When step 1, alternating current machine are restarted, first estimate the current magnetic linkage angle of described alternating current machine;

Step 2, the stator current vector of described alternating current machine is carried out to coordinate transform, obtains respectively first current value identical with estimated magnetic linkage angle direction, and one with orthogonal the second current value of estimated magnetic linkage angle direction;

Step 3, using the predetermined current value of the first current value and a non-zero as input, obtain a voltage u through current regulator computing _m; Using the second current value and 0 as input, obtain a voltage u through current regulator computing _t;

Step 4, with voltage u _mand u _tas input, utilize pulse-width modulation to generate drive control signal and drive described alternating current machine;

Step 5, repeated execution of steps 1～step 4, until described the second current value is lower than default current threshold and maintain one default period; The magnetic linkage angle that described alternating current machine is current is differentiated, the rotating speed when obtaining described alternating current machine and restarting.

2. the rotating-speed tracking method of alternating current machine as claimed in claim 1, is characterized in that, the stator magnetic linkage angle that described magnetic linkage angle is described alternating current machine obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{{\mathrm{\ψ}}_{\mathrm{s\α}}}\right)$

In formula,

for estimated stator magnetic linkage angle; ψ _{s α}, ψ _{s β}be respectively stator magnetic linkage vector under alpha-beta two-phase static coordinate

at the component of α, β direction,

obtain according to following formula:

Wherein,

with be respectively the stator voltage vector stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance.

3. the rotating-speed tracking method of alternating current machine as claimed in claim 1, is characterized in that, the rotor flux angle that described magnetic linkage angle is described alternating current machine obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{r\β}}}{{\mathrm{\ψ}}_{\mathrm{r\α}}}\right)$

In formula,

for estimated rotor flux angle; ψ _{r α}, ψ _{r β}be respectively alpha-beta two-phase static coordinate lower rotor part flux linkage vector

at the component of α, β direction, obtain according to following formula:

Wherein,

with be respectively the stator voltage vector stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance,

l _mfor alternating current machine mutual inductance, L _rfor AC motor rotor inductance, L _sfor alternating-current motor stator self-induction.

4. the rotating-speed tracking method of alternating current machine as claimed in claim 1, is characterized in that, described magnetic linkage angle is described alternating current machine without stator resistance magnetic linkage angle, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{{\mathrm{\ψ}}_{\mathrm{s\α}}}\right)$

In formula, for estimated without stator resistance magnetic linkage angle; ψ _{s α}, ψ _{s β}be respectively under alpha-beta two-phase static coordinate without stator resistance flux linkage vector

at the component of α, β direction,

obtain according to following formula:

Wherein,

for the stator voltage vector of described alternating current machine.

5. speed regulating device for alternating current machine, comprising: PWM module, inverter module and voltage reconstructed module; Described PWM module is modulated to the voltage signal of input the control signal of inverter module, and described inverter module drives described alternating current machine according to the control signal of PWM module output, and described voltage reconstructed module is used for calculating stator voltage vector; It is characterized in that, described speed regulating device also comprise rotating speed search module, and described rotating speed search module comprises coordinate transformation module, the first current regulator, the second current regulator, magnetic linkage angle estimation device and differential module; In the time that described alternating current machine is restarted, magnetic linkage angle estimation device first estimates the current magnetic linkage angle of described alternating current machine, and by the current magnetic linkage angle input coordinate conversion module estimating; Coordinate transformation module carries out coordinate transform to the stator current vector of described alternating current machine, obtain respectively first current value identical with estimated magnetic linkage angle direction, and one with orthogonal the second current value of estimated magnetic linkage angle direction, and the first current value and the second current value are inputted respectively to the first current regulator, the second current regulator; The first current regulator is using the predetermined current value of the first current value and a non-zero as input, and computing obtains a voltage u _m; The second current regulator is using the second current value and 0 as input, and computing obtains a voltage u _t; Described PWM module is with voltage u _mand u _tas input, the control signal that generates inverter module drives described alternating current machine; When described the second current value is lower than default current threshold and maintain one section of default time t, the current magnetic linkage angle that described differential module estimates magnetic linkage angle estimation device is differentiated, the rotating speed when obtaining described alternating current machine and restarting.

6. the speed regulating device of alternating current machine as claimed in claim 5, is characterized in that, the stator magnetic linkage angle that the magnetic linkage angle of described magnetic linkage angle estimation device output is described alternating current machine, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{{\mathrm{\ψ}}_{\mathrm{s\α}}}\right)$

In formula,

for estimated stator magnetic linkage angle; ψ _{s α}, ψ _{s β}be respectively stator magnetic linkage vector under alpha-beta two-phase static coordinate

at the component of α, β direction,

obtain according to following formula:

Wherein,

with

be respectively the stator voltage vector stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance.

7. the speed regulating device of alternating current machine as claimed in claim 5, is characterized in that, the rotor flux angle that the magnetic linkage angle of described magnetic linkage angle estimation device output is described alternating current machine, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{r\β}}}{{\mathrm{\ψ}}_{\mathrm{r\α}}}\right)$

In formula,

for estimated rotor flux angle; ψ _{r α}, ψ _{r β}be respectively alpha-beta two-phase static coordinate lower rotor part flux linkage vector

at the component of α, β direction, obtain according to following formula:

Wherein,

with

be respectively the stator voltage vector stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance,

l _mfor alternating current machine mutual inductance, L _rfor AC motor rotor inductance, L _sfor alternating-current motor stator self-induction.

8. the speed regulating device of alternating current machine as claimed in claim 5, is characterized in that, the magnetic linkage angle of described magnetic linkage angle estimation device output is described alternating current machine without stator resistance magnetic linkage angle, obtains according to following formula estimation:

${\widehat{\mathrm{\θ}}}_2=\arctan \left(\frac{{\mathrm{\ψ}}_{\mathrm{s\β}}}{{\mathrm{\ψ}}_{\mathrm{s\α}}}\right)$

In formula,

for estimated without stator resistance magnetic linkage angle; ψ _{s α}, ψ _{s β}be respectively under alpha-beta two-phase static coordinate without stator resistance flux linkage vector

at the component of α, β direction,

obtain according to following formula:

Wherein,

for the stator voltage vector of described alternating current machine.

9. the speed regulating device of alternating current machine as claimed in claim 5, is characterized in that, described rotating speed search module also comprises filtration module, and its input is connected with the output of described differential module.

10. an alternating current machine, comprises speed regulating device as described in claim 5～9 any one.

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