CN103795319B - A kind of rotating-speed tracking method of alternating current machine, speed regulating device and alternating current machine - Google Patents

Abstract

The invention discloses a kind of rotating-speed tracking method of alternating current machine, for following the tracks of rotating speed when alternating current machine is restarted.The method comprises: 1, estimate current magnetic linkage angle; 2, coordinate transform is carried out to stator current vector, obtain first current value identical, orthogonal with magnetic linkage angle direction, the second current value respectively; 3, using the pre-set current value of the first current value and a non-zero as input, a voltage is obtained through current regulator computing u _m; Using the second current value and 0 as input, obtain a voltage u through current regulator computing _r; 4, to voltage u _mand u _rcarry out pulse-width modulation and generate drive control signal driving alternating current machine; 5, repeated execution of steps 1 ~ 4, until the second current value maintains one default period lower than a current threshold; Current magnetic linkage angle is differentiated, obtains rotating speed when alternating current machine is restarted.The invention also discloses a kind of speed regulating device and alternating current machine of alternating current machine.The present invention has quick and precisely and the low advantage of cost.

Description

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

Technical field

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

Background technology

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

(application number is 201110077358.0 to one section of Chinese patent literature, publication date is 2012-09-26) disclose a kind of rotating-speed tracking method of induction motor, it is to the effect that: when DC bus voltage error judgment module judges that this detection DC bus voltage is more than or equal to setting DC bus voltage, or when 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, transmit this to allow switch and first control signal to this voltage modulation module, this voltage modulation module receives control inverter driven induction motor after this first control signal, otherwise this frequency searching module then transmits this and second controls signal to voltage modulation module, with the stator field frequency making this this inverter of voltage modulation module controls change this induction motor, and again carry out the judgement of aforementioned DC bus voltage error judgment module and this current error judge module.

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

There is following problem in technical scheme described in above-mentioned document: 1) determination of the first control signal is more very difficult, if arrange improper, 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, when especially stator field frequency is contrary with induction motor actual speed 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 of alternating current machine, speed regulating device and alternating current machine are provided, rotating speed size and Orientation when alternating current motor is restarted can be estimated fast and effectively, 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, for following the tracks of rotating speed when alternating current machine is restarted, described rotating-speed tracking method comprises:

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

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

Step 3, using the pre-set 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 second current value maintains one default period lower than the current threshold preset; The magnetic linkage angle current to described alternating current machine is differentiated, and namely obtains rotating speed when described alternating current machine is restarted.

Speed regulating device for alternating current machine, comprising: PWM module, inverter module and voltage reconstruction module; The voltage signal modulation of input is the control signal of inverter module by described PWM module, and described inverter module drives described alternating current machine according to the control signal that PWM module exports, and described voltage reconstruction module is 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; When described alternating current machine is restarted, magnetic linkage angle estimation device first estimates the current magnetic linkage angle of described alternating current machine, and the current magnetic linkage angle input coordinate conversion module that will estimate; Coordinate transformation module carries out coordinate transform to the stator current vector of described alternating current machine, obtain first current value identical with estimated magnetic linkage angle direction respectively, and the second current value that orthogonal with estimated magnetic linkage angle direction, and the first current value and the second current value are inputted the first current regulator, the second current regulator respectively; First current regulator is using the pre-set current value of the first current value and a non-zero as input, and computing obtains a voltage u _m; 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 generating inverter module drives described alternating current machine; When described second current value maintains one section of default time t lower than the current threshold preset, described differential module is differentiated to the current magnetic linkage angle that magnetic linkage angle estimation device estimates, obtain rotating speed when described alternating current machine is restarted.

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

The first preferred version: described magnetic linkage angle is the stator magnetic linkage angle of 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 in α, β direction, obtain according to following formula:

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

The second preferred version: described magnetic linkage angle is the rotor flux angle of 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 in α, β direction, obtain according to following formula:

Wherein, with be respectively stator voltage vector and the 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 be described alternating current machine without stator resistance magnetic linkage angle, obtain according to the estimation of following formula:

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

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 in 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 that differential module exports, more stable motor can be obtained 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; Thus the rotating speed size and Orientation that can fast and effeciently estimate when restarting, and then realize stable restart function.

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 and direction synchronously to estimate, rotating speed is short and controlled for 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 wide, easily to realize and compatible strong;

Three, the present invention can based on existing device and circuit realiration, 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 described in detail:

Fig. 1 shows 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 reconstruction module, the voltage signal modulation of input is the input control signal of inverter module by PWM module, the control signal that inverter module exports according to PWM module drives alternating current motor, and voltage reconstruction module calculates stator voltage vector by the control signal gathering busbar voltage Udc and PWM module output as shown in the figure, speed regulating device of the present invention also comprise rotating speed search module (as shown in dotted box portion in figure), this rotating speed search module comprises: coordinate transformation module, first current regulator ACR_M, 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 of the first switch S 1 holds and connects VF(Variable-frequency, frequency conversion) output of control unit, the input b of the first switch S 1 holds the output of connection second current regulator ACR_T, the input a of second switch S2 holds the output connecting VF control unit, the input b of second switch S2 holds the output of connection first current regulator ACR_M, when speed regulating device normally run, switch S 1 and S2 hold with respective a and are connected, VF control unit receiving frequency signals ω output voltage signal are to PWM module, the voltage signal modulation of input is the input control signal of inverter module by PWM module, described inverter module controls output power to alternating current motor according to the output control signal of PWM module, when starting again after RHVC shuts down, need to follow the tracks of the rotating speed of alternating current motor, first switch S 1 and second switch S2 are switched to respective b end by PWM module.

When carrying out rotating-speed tracking, first by the stator current vector of current sampling devices Sample AC motor the control signal simultaneously exported according to busbar voltage Udc and PWM module by voltage reconstruction module calculates stator voltage vector and will with input magnetic linkage angle estimation device G; Estimate the angle of current magnetic linkage and the angle of current magnetic linkage that will estimate 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 non-zero current value that one sets by the first current regulator ACR_M 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 _tlevel off to 0(by with one preset level off to 0 current threshold compare judge), and after maintaining one section of default time t, by the angle of magnetic linkage obtained output variable is obtained after differential module D computing be the rotating speed of required alternating current motor; Further, output variable can obtain through filtration module LP computing namely the more stable rotating speed of alternating current motor is obtained; Finally the first switch S 1 and second switch S2 are connected to respective a end, by the rotating speed obtained as the input of VF control unit, export two control voltages and be input to PWM module and carry out control inverter module thus the operation of tracing control 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, and the evaluation method of three kinds of magnetic linkage angles is as follows respectively:

(1) the magnetic linkage angle that described magnetic linkage angle estimation device exports is the stator magnetic linkage angle of 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 in α, β direction, obtain according to following formula:

Wherein, with be respectively stator voltage vector and the stator current vector of described alternating current machine, R _sfor described alternating-current motor stator resistance.Wherein, stator resistance R _sa given d. c. voltage signal U, Sample AC motor output current I can be passed through, then by formula R _s=U/I computing is obtained.

(2) the magnetic linkage angle that described magnetic linkage angle estimation device exports is the rotor flux angle of 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 in α, β direction, obtain according to following formula:

Wherein, with be respectively stator voltage vector and the 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, magnetic linkage angle estimation device can be pre-entered.

(3) the magnetic linkage angle that described magnetic linkage angle estimation device exports be described alternating current machine without stator resistance magnetic linkage angle, obtain according to the estimation of following formula:

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

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 in 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, for following the tracks of rotating speed when alternating current machine is restarted, is characterized in that, described rotating-speed tracking method comprises:

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

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

Step 3, using the pre-set current value of the first current value and a non-zero as input, obtain a voltage u through the first current regulator computing _m; Using the second current value and 0 as input, obtain a voltage u through the second 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 second current value maintains one default period lower than the current threshold preset; The magnetic linkage angle current to described alternating current machine is differentiated, and namely obtains rotating speed when described alternating current machine is restarted.

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

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

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 in α, β direction, obtain according to following formula:

Wherein, with be respectively stator voltage vector and the 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, it is characterized in that, described magnetic linkage angle is the rotor flux angle of described alternating current machine, obtains according to following formula estimation:

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

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 in α, β direction, obtain according to following formula:

Wherein, with be respectively stator voltage vector and the 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 be described alternating current machine without stator resistance magnetic linkage angle, obtain according to following formula estimation:

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

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 in 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 reconstruction module; The voltage signal modulation of input is the control signal of inverter module by described PWM module, and described inverter module drives described alternating current machine according to the control signal that PWM module exports, and described voltage reconstruction module is 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; When described alternating current machine is restarted, magnetic linkage angle estimation device first estimates the current magnetic linkage angle of described alternating current machine, and the current magnetic linkage angle input coordinate conversion module that will estimate; Coordinate transformation module carries out coordinate transform to the stator current vector of described alternating current machine, obtain first current value identical with estimated magnetic linkage angle direction respectively, and the second current value that orthogonal with estimated magnetic linkage angle direction, and the first current value and the second current value are inputted the first current regulator, the second current regulator respectively; First current regulator is using the pre-set current value of the first current value and a non-zero as input, and computing obtains a voltage u _m; 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 generating inverter module drives described alternating current machine; When described second current value maintains one section of default time t lower than the current threshold preset, described differential module is differentiated to the current magnetic linkage angle that magnetic linkage angle estimation device estimates, obtain rotating speed when described alternating current machine is restarted.

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

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 in α, β direction, obtain according to following formula:

Wherein, with be respectively stator voltage vector and the 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 magnetic linkage angle that described magnetic linkage angle estimation device exports is the rotor flux angle of described alternating current machine, obtains according to following formula estimation:

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 in α, β direction, obtain according to following formula:

Wherein, with be respectively stator voltage vector and the 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 that described magnetic linkage angle estimation device exports be described alternating current machine without stator resistance magnetic linkage angle, obtain according to the estimation of following formula:

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 in 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, it 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 any one of claim 5 ~ 9.