CN108777558A - A kind of brushless dual-feed motor feedforward current control system, feedforward current controller and its design method - Google Patents

Abstract

The invention discloses a feedforward current control system of a brushless double-fed motor, a feedforward current controller and a design method thereof. The control system includes a power grid, a brushless double-fed motor, a first converter, a second converter, and a flux linkage Calculation module, angle calculation module, angular velocity calculation module, photoelectric encoder disc, feedforward current controller, third converter, fourth converter, SVPWM pulse generator, control winding side power converter and DC side; the control system of the present invention The medium feedforward current controller has a simple and compact control structure, high control precision, and fast current dynamic response; this system adds feedforward compensation on the basis of fully considering the complete current loop characteristics of the control winding, which greatly improves the stator current of the control winding. The control effect can achieve better stability and faster dynamic performance; the control system has high stability and can effectively expand the stable operation range of the brushless doubly-fed motor, and maintain good performance at different operating speeds.

Description

A brushless doubly-fed motor feed-forward current control system, feed-forward current controller and its design method

technical field

The invention relates to a brushless doubly-fed motor control system, in particular to a brushless doubly-fed motor feed-forward current control system, a feed-forward current controller and a design method thereof.

Background technique

With the development of motor manufacturing technology, an AC motor with better performance - brushless doubly-fed motor has played an increasingly important role in the fields of ship power generation, variable speed and constant frequency power generation systems, and speed control systems. Brushless double-fed motors can realize asynchronous operation, synchronous operation and double-fed operation. Brushless double-fed motor has stable performance and simple structure. At the same time, the inverter required for control has a small capacity and low cost. Compared with the widely used double-fed motor, it has no brushes and slip rings and has higher reliability. However, there are still problems such as high control difficulty and large rotor loss, and further research on the control performance of brushless doubly-fed motors is still needed.

The control methods of brushless doubly-fed motors include scalar control, vector control, direct torque control, etc. Scalar control is to directly control the stator voltage and frequency of the power winding and control winding, and then change the running state of the motor. Since only the voltage and frequency need to be controlled, the control algorithm is relatively simple, but its anti-interference ability is poor; vector control mainly through The current loop controls the brushless double-fed motor, and the existing research has not considered the analysis of the stability and dynamics of the control system; the direct torque control needs to measure the terminal voltage, current and speed of the motor to estimate the flux linkage and rotation speed of the motor. Torque, and then realize the control of the motor, the existing control method lacks the research on the characteristics of the current loop of the control winding, and the stability and dynamics of the control system are not good.

Contents of the invention

Purpose of the invention: In order to solve the problems of the prior art, the present invention proposes a brushless doubly-fed motor feed-forward current control system, a feed-forward current controller and a design method thereof.

Technical solution: The present invention provides a feed-forward current control system for a brushless doubly-fed motor, the control system includes a power grid, a brushless doubly-fed motor, a first converter, a second converter, a flux calculation module, and an angle calculation module , angular velocity calculation module, photoelectric encoder disk, feedforward current controller, third converter, fourth converter, SVPWM pulse generator, control winding side power converter and DC side;

Among them, the power winding and control winding of the brushless doubly-fed motor are respectively connected to the power grid and the power converter, and the other end of the power converter is connected to the DC side; the input of the first converter is connected to the power winding of the brushless doubly-fed motor, and the output Connect the feed-forward current controller; the input of the second converter is connected to the power winding of the brushless doubly-fed motor, and the output is connected to the flux calculation module; one output of the flux calculation module is connected to the feed-forward current controller, and the other output is connected to the first One converter, the other is connected to the angle calculation module, and the third is connected to the angular velocity calculation module through a differentiator; the output of the angular velocity calculation module is connected to the feedforward current controller; the photoelectric encoder disc is installed on the brushless doubly-fed motor rotor, and the photoelectric encoder disc One output of the output is connected to the angular velocity calculation module through the differentiator, and the other is connected to the angle calculation module. The output of the angle calculation module is respectively connected to one input of the third converter and the fourth converter; the other input of the third converter is connected to the brushless The control winding of the double-fed motor is connected, and its output is connected with the feedforward current controller; the output of the feedforward current controller is connected with the fourth converter, and the output of the fourth converter is connected with the input of the SVPWM pulse generator, and the SVPWM pulse is generated The output of the converter is connected to the input of the power converter.

Preferably, the feedforward current controller includes a first comparison unit, a proportional-integral controller, a first feedforward compensation item, a second feedforward compensation item, a third feedforward compensation item, a second comparison unit and a third comparison unit unit, wherein the input of the first comparison unit is the control winding reference current vector i _cs ^* and the actual current vector i _cs , the output of the first comparison unit is connected with the input of the proportional-integral controller, and the output of the proportional-integral controller is connected with the second One input of the comparison unit is connected, the third feedforward compensation item is used as another input of the second comparison unit, the output of the second comparison unit is connected with an input of the third comparison unit, the first feedforward compensation item and the second feedforward compensation The compensation item is used as the other two input items of the third comparison unit, the output of the third comparison unit is the reference voltage vector u _cs ^* of the control winding, the actual current vector i _ps of the power winding is taken as the input of the first feed-forward compensation item, and the actual current vector of the control winding is The current vector i _cs is used as the input of the second feed-forward compensation term.

Preferably, the flux linkage calculation module collects the values u _pαs and _{up pβs} of the power winding stator voltage in the two-phase stationary coordinate system, and uses _{up pαs} and _{up pβs to} calculate the phase angle θ _u and the amplitude |u of the power winding stator voltage _s |:

According to the relationship between the stator voltage of the power winding and the flux linkage, the phase angle θ _p and the amplitude ψ _p of the power winding flux linkage are calculated:

Among them, ω _p is the angular velocity of the electric quantity of power winding.

Preferably, the angle calculation module calculates the angle θ _c of the control winding electricity from the rotor position angle θ _m obtained by the photoelectric encoder disk and the flux calculation module and the phase angle θ _p of the power winding flux, and the relationship between them is:

θ _c = θ _p -(p _p +p _c ) θ _m ;

Among them, p _p and p _c are the pole pairs of the power motor and the control motor respectively.

Preferably, the angular velocity calculation module differentiates the rotor position angle θ _m and the power winding flux linkage phase angle θ _p obtained by the photoelectric encoder disc and the flux linkage calculation module, and calculates the rotor angular velocity ω _m and the angular velocity ω _p of the power winding electric quantity :

Then, according to the relationship between the angular velocity ω _c of the control winding electric quantity and ω _m and ω _p , the size of ω _c is calculated, and the relationship between them is:

ω _c =ω _p -(p _p +p _c )ω _m ;

Among them, p _p and p _c are the pole pairs of the power motor and the control motor respectively.

Preferably, the SVPWM pulse generator uses space vector pulse width modulation technology to generate three-phase PWM waves.

Preferably, the control winding side power converter adopts a three-phase full-bridge inverter circuit.

The present invention also provides a feedforward current controller, including a first comparison unit, a proportional-integral controller, a first feedforward compensation item, a second feedforward compensation item, a third feedforward compensation item, a second comparison unit and The third comparison unit, wherein the input of the first comparison unit is the control winding reference current vector i _cs ^* and the actual current vector i _cs , the output of the first comparison unit is connected with the input of the proportional-integral controller, and the output of the proportional-integral controller It is connected with one input of the second comparison unit, the third feedforward compensation item is used as another input of the second comparison unit, the output of the second comparison unit is connected with an input of the third comparison unit, the first feedforward compensation item and the second The second feed-forward compensation item is used as the other two input items of the third comparison unit, the output of the third comparison unit is the reference voltage vector u _cs ^* of the control winding, and the actual current vector i _ps of the power winding is used as the input of the first feed-forward compensation item, The actual current vector i _cs of the control winding is used as the input of the second feed-forward compensation term.

Preferably, the first feed-forward compensation item is It includes the first-order inertia link, where k ₂ =L _mc /L _mp , L _mc , L _mp , and L _sp are the mutual inductance of the control winding, the mutual inductance of the power winding, and the self-inductance of the power winding, respectively, and τ is the first-order inertia link The time constant of , ω _c is the electric angular velocity of the control winding, _ips is the actual current vector of the power winding, and its dq axis current components are i _pds and i _pqs ;

The second feedforward compensation item is the inductance feedforward item jω _c L _sc i _cs , L _sc is the self-inductance of the control winding, i _cs is the actual current vector of the control winding, and its dq axis current components are i _cds and i _cqs ;

The third feedforward compensation item is the flux feedforward item jω _c k ₂ ψ _p , and ψ _p is the magnitude of the power winding flux linkage.

The present invention also provides a method of designing the above-mentioned feedforward current controller, the method comprising the following steps:

(1) Construct a complete model of the control winding current loop, and its complete model formula is:

(R _sc +sL _sc )i _cs (s)＝u _cs (s)-k ₂ (s+jω _c )L _sp i _ps (s)-jω _c L _sc i _cs (s)+k ₂ (s+ jω _c )ψ _p (s);

Among them, R _sc is the resistance of the control winding, L _sc is the self-inductance of the control winding, u _cs is the actual voltage vector of the control winding, and its dq axis components are u _cds and u _cqs ; k ₂ =L _mc /L _mp , L _mc , L _mp , L _sp are the mutual inductance of the control winding, the mutual inductance of the power winding, and the self-inductance of the power winding respectively; ω _c is the electric angular velocity of the control winding; ip _ps is the actual current vector of the power winding, and its dq axis components are i _pds and i _pqs ; _ics is the actual current vector of the control winding, and its dq axis components are i _cds and i _cqs ; ψ _p is the flux linkage amplitude of the power winding;

(2) Establish the coupling relationship between the actual current vector i _ps of the power winding and the actual current vector i _cs of the control winding, the coupling relationship is:

Among them, k=L _mp L _mc /(L _sp L _r ′), k ₁ ＝L _r /L _r ′, L _r is the rotor inductance, L _r ′=L _r -L _mp ² /L _sp is the transient state of the rotor inductance; and

Among them, ω _m is the rotor speed, T _r 'is the transient time constant of the rotor, T _r '=L _r ′/R _r , L _r ′=L _r -L _mp ² /L _sp is the transient inductance of the rotor, R _r is the rotor resistance;

(3) Based on the model in step (1) and the coupling relationship in step (2), construct the structure of the control winding current loop, where the first-order inertia link G _RL (s)=1/(R _sc +sL _sc ) It is the core of the current loop of the control winding. The current loop has two i _cs feedback branches, respectively denoted as branch I and branch II, where branch I is the coupling path between the two currents of i _ps and i _cs , and the control The actual current vector i _cs of the winding is fed back to the actual voltage vector u _cs of the control winding through two series links, represented by k(1+G _r (s)) and k ₂ L _sp (s+jω _c ) respectively; Branch II is jω _c L _sc ;

(4) According to the structure of the control winding current loop in step (3), design the compensation item of the feedforward current controller

Will As a feed-forward term, the branch I is equivalently cut off, so that As the first feed-forward compensation item, where, k ₂ =L _mc /L _mp , L _mc , L _mp , L _sp are the mutual inductance of the control winding, the mutual inductance of the power winding, and the self-inductance of the power winding respectively, and τ is the first-order inertia The time constant of the link, ω _c is the angular velocity of the control winding electricity, _ips is the actual current vector of the power winding, and its dq axis current components are i _pds and i _pqs ; the second feedforward compensation item is the inductance feedforward jω _c L _sc i _cs , where L _sc is the self-inductance of the control winding, _ic is the actual current vector of the control winding, and its dq-axis current components are i _cds and i _cqs ; the third feed-forward compensation item is the flux feed-forward item jω _c k ₂ ψ _p , where ψ _p is the magnitude of the power winding flux linkage.

Beneficial effects: Compared with the prior art, the control structure of the feedforward current controller in the control system of the present invention is simple and compact, with high control precision and fast current dynamic response; the control system provided by the present invention fully considers the complete current of the control winding On the basis of loop characteristics, feedforward compensation is added, which greatly improves the control effect of controlling the stator current of the winding, and can achieve better stability and faster dynamic performance; at the same time, the control system of the present invention has high stability and can effectively expand infinite The brush double-fed motor has a stable operating range and maintains good performance at different operating speeds.

Description of drawings

Fig. 1 is a structural representation of the control system of the present invention;

Figure 2 is a schematic diagram of the control winding current loop structure;

Fig. 3 is a structural schematic diagram of a feedforward current controller;

Figure 4 is the experimental waveform diagram of the brushless doubly-fed motor running at 400r/min;

Figure 5 is the experimental waveform diagram of the brushless doubly-fed motor running at 600r/min;

Figure 6 is the experimental waveform diagram of the brushless doubly-fed motor running at 666r/min.

Detailed ways

The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, a feed-forward current control system for a brushless doubly-fed motor, its structure includes a grid 1, a brushless doubly-fed motor 2, a first converter 3, a second converter 4, a flux calculation module 5, Angle calculation module 6, angular velocity calculation module 7, photoelectric encoder disk 8, feedforward current controller 9, third converter 14, fourth converter 10, SVPWM pulse generator 11, control winding side power converter 12 and DC side 13. The power winding and control winding of the brushless double-fed motor are respectively connected to the grid 1 and the power converter 12, and the other end of the power converter is connected to the DC side 13; the input of the first converter is connected to the grid and the brushless double-fed motor The output of the power winding is connected to the feed-forward current controller; the input of the second converter is connected to the grid and the power winding of the brushless doubly-fed motor, the output is connected to the flux calculation module, and one output of the flux calculation module is connected to the feed-forward current controller , the other output is connected to the first converter, the other is connected to the angle calculation module, the third is connected to the angular velocity calculation module through the differentiator, and the output of the angular velocity calculation module is connected to the feedforward current controller; the photoelectric encoder is installed on the brushless double-fed On the motor rotor, it is used to measure the rotor position angle θ _m of the brushless doubly-fed motor. The output of the photoelectric encoder is connected to the angular velocity calculation module through a differentiator, and the other is connected to the angle calculation module. The output of the angle calculation module is respectively connected to the third transformation The input of the converter 14 is connected with the fourth converter 10; the other input of the third converter is connected with the control winding of the brushless doubly-fed machine, and its output is connected with the feed-forward current controller; the output of the feed-forward current controller is connected with the The fourth converter is connected, the output of the fourth converter is connected with the input of the SVPWM pulse generator, and the output of the SVPWM pulse generator is connected with the input of the power converter.

Among them, the first converter is a 3s/2r converter, which transforms the power from the three-phase stationary coordinate system to the two-phase rotating coordinate system; the second converter is a 3s/2s converter, which transforms the power from the three-phase stationary coordinate system to the two-phase rotating coordinate system. Two-phase stationary coordinate system; the third converter is a 3s/2r converter, which transforms the power from the three-phase stationary coordinate system to a two-phase rotating coordinate system; the fourth converter is a 2r/2s converter, which converts the power from two-phase rotation The coordinate system is transformed to a two-term stationary coordinate system.

The control system of the present invention first converts the three-phase voltage signals u _pas , u _pbs , and u _pcs collected by the power grid into up _pαs and up _pβs in the two-phase static coordinate system through the second converter, and uses the flux linkage calculation module to calculate Obtain the phase angle θ _p and amplitude ψ _p of the flux linkage of the power winding; collect the three-phase current signals i _pas , i _pbs , and i _pcs and convert them into i _pds and i _pqs in the two-phase rotating coordinate system through the first converter; Combining the rotor position angle θ _m and the power winding flux phase angle θ _p , use the angle calculation module to obtain the angle θ _c of the control winding electric quantity; differentiate the rotor position angle θ _m and the power winding flux phase angle θ _p respectively, and calculate The rotor angular velocity ω _m and the angular velocity ω _p of the power winding electric quantity are obtained, and combined with the angular velocity calculation module, the angular velocity ω _c of the control winding electric quantity is calculated. Then input the dq-axis reference current i _cds ^* , i _cqs ^* and actual current i _pds , i _pqs , and other variables ψ _p , θ _c , ω _c etc. into the feedforward current controller to obtain the control voltage u of the controlled object _cds ^* , u _cqs ^* . After that, u _cds ^* and u _cqs * are transformed into two-phase stationary coordinate system control voltages u _cαs ^* and u _cβs ^* through the fourth converter ^. Combining u _cαs ^* and u _cβs ^* , use SVPWM pulse generator to get the control pulse of the power converter, input it to the power converter on the control winding side to get the control voltage of the control winding, and finally realize the effective control of the brushless doubly-fed motor .

The present invention proposes the design method of feedforward current controller, comprises the following steps:

(1) Construct a complete model of the control winding current loop, and its complete model can be expressed as:

(R _sc +sL _sc )i _cs (s)＝u _cs (s)-k ₂ (s+jω _c )L _sp i _ps (s)-jω _c L _sc i _cs (s)+k ₂ (s+ jω _c )ψ _p (s) (1);

Among them, R _sc is the resistance of the control winding, L _sc is the self-inductance of the control winding, u _cs is the actual voltage vector of the control winding, and its dq axis components are u _cds and u _cqs , k ₂ =L _mc /L _mp , L _mc , L _mp , and L _sp are the mutual inductance of the control winding, the mutual inductance of the power winding, and the self-inductance of the power winding respectively; ω _c is the electrical angular velocity of the control winding; _{ip ps} is the actual current vector of the power winding, and its dq axis components are i _pds and i _pqs , i _cs is the actual current vector of the control winding, its dq axis components are i _cds and i _cqs , and ψ _p is the magnitude of the power winding flux linkage.

(2) Establish the coupling relationship between the actual current vector i _ps of the power winding and the actual current vector i _cs of the control winding, the coupling relationship is:

Among them, k=L _mp L _mc /(L _sp L _r ′), k ₁ ＝L _r /L _r ′, L _r is the rotor inductance, L _r ′=L _r -L _mp ² /L _sp is the transient state of the rotor inductance. and

Among them, ω _m is the rotor speed, T _r 'is the transient time constant of the rotor, T _r '=L _r ′/R _r , L _r ′=L _r -L _mp ² /L _sp is the transient inductance of the rotor, R _r is the rotor resistance.

(3) Based on the model in step (1) and the coupling relationship in step (2), construct the structure of the control winding current loop, as shown in Figure 2. In Fig. 2, the first-order inertial link G _RL (s)=1/(R _sc +sL _sc ) is the core of the control winding current loop, and the current loop has two i _cs feedback branches, respectively denoted as branch I and branch Road II. Branch I represents the coupling path between the currents of the two electrical ports (i _ps and i _cs ). Among them, the actual current vector i _cs of the control winding is fed back to the actual voltage vector u _cs of the control winding through two series links, represented by k(1+G _r (s)) and k ₂ L _sp (s+jω _c ) respectively; Branch II is jω _c L _sc .

(4) According to the structure of the control winding current loop in step (3), design the compensation item of the feedforward current controller

As shown in the branch I in Fig. 2, the control winding current vector i _cs is fed back to the control winding actual voltage vector u _cs through two series links, respectively by k(1+G _r (s)) and k ₂ L _sp (s+jω _c ) means. Since branch I is more complex, it is not appropriate to add the whole branch as a feed-forward item, however, the above two links are _coupled through the actual current vector i of the power _winding , which is easy to measure. Will As a feed-forward term, the branch I can be cut off equivalently, so that As the first feed-forward compensation item, where, k ₂ =L _mc /L _mp , L _mc , L _mp , L _sp are the mutual inductance of the control winding, the mutual inductance of the power winding, and the self-inductance of the power winding respectively, and τ is the first-order inertia The time constant of the link, ω _c is the angular velocity of the electric quantity of the control winding, _ips is the actual current vector of the power winding, and its dq-axis current components are i _pds and i _pqs ; at the same time, in order to optimize the control effect, a second front feed-forward current controller is added The feed-forward compensation item and the third feed-forward compensation item, the second feed-forward compensation item is the inductance feed-forward item jω _c L _sc i _cs , where L _sc is the self-inductance of the control winding, _ic is the actual current vector of the control winding, and its dq The shaft current components are i _cds and _icqs ; the third feedforward compensation item is the flux feedforward item jω _c k ₂ ψ _p , where ψ _p is the magnitude of the power winding flux linkage.

In summary, the block diagram of the feedforward current controller designed according to the above design method is shown in Figure 3, and its structure includes a first comparison unit 21, a proportional-integral controller 22, a first feedforward compensation item 23, a second Feedforward compensation item 24, the third feedforward compensation item 25, the second comparison unit 26 and the third comparison unit 27, wherein the input of the first comparison unit is the dq axis of the control winding reference current vector i _cs ^* (i _cs ^* The components are i _cds ^* and i _cqs ^* ) and the actual current vector i _cs (the dq axis components of i _cs are i _cds and i _cqs ), the output of the first comparison unit is connected with the input of the proportional-integral controller, and the proportional-integral controller The output of the second comparison unit is connected to an input of the second comparison unit, the third feedforward compensation item is used as another input of the second comparison unit, the output of the second comparison unit is connected to an input of the third comparison unit, and the first feedforward compensation item and the second feed-forward compensation item as the other two input items of the third comparison unit, the output of the third comparison unit is the control winding reference voltage vector u _cs ^* (the dq axis components of u _cs ^* are u _cds ^* and u _cqs ^* ), the actual current vector i _ps of the power winding (the dq axis components of i _ps are i _pds and i _pqs ) is used as the input of the first feedforward compensation item, and the actual current vector i _cs of the control winding is used as the input of the second feedforward compensation item.

The first comparison unit 21 is used to obtain the difference between the dq axis reference current vector i _cs ^* and the actual current vector i _cs of the control winding.

The proportional-integral controller 22 is used to obtain the control signal of the controlled object, and the PI parameters of the proportional-integral controller are set as k _p =gL _sc and _ki =gR _sc , where g is the gain of the PI controller.

The first feedforward compensation item 23 is: It includes the first-order inertia link, where k ₂ =L _mc /L _mp , L _mc , L _mp , and L _sp are the mutual inductance of the control winding, the mutual inductance of the power winding, and the self-inductance of the power winding, respectively, and τ is the first-order inertia link The time constant of , ω _c is the electric angular velocity of the control winding, _ips is the actual current vector of the power winding, and its dq axis current components are i _pds and i _pqs ;

The second feed-forward compensation item 24 is the inductance feed-forward item jω _c L _sc i _cs , L _sc is the self-inductance of the control winding, i _cs is the actual current vector of the control winding, and its dq axis current components are i _cds and i _cqs .

The third feed-forward compensation item 25 is the flux feed-forward item jω _c k ₂ ψ _p , and ψ _p is the flux linkage amplitude of the power winding.

In Figure 1, the flux linkage calculation module first collects the values u _pαs and u _pβs of the stator voltage of the power winding in the two-phase stationary coordinate system, and uses u _pαs and u _{pβs to} calculate the phase angle θ _u and the amplitude |u _s of the stator voltage of the power winding |:

According to the relationship between the stator voltage of the power winding and the flux linkage, the phase angle θ _p and the amplitude ψ _p of the power winding flux linkage are calculated:

Angle calculation module, from the rotor position angle θ _m and the power winding flux phase angle θ _p obtained by the photoelectric encoder disk and the flux calculation module, the angle θ _c of the control winding electric quantity is calculated, and the relationship between them is

θ _c = θ _p -(p _p +p _c ) θ _m (8);

Among them, p _p and p _c are the pole pairs of the power motor and the control motor respectively.

The angular velocity calculation module first differentiates the rotor position angle θ _m and the power winding flux phase angle θ _p obtained by the photoelectric encoder disk and the flux linkage calculation module, and calculates the rotor angular velocity ω _m and the angular velocity ω _p of the power winding electricity:

Then, according to the relationship between the angular velocity ω _c of the control winding electric quantity and ω _m and ω _p , the size of ω _c is calculated, and the relationship between them is:

ω _c =ω _p -(p _p +p _c )ω _m (10);

Among them, p _p and p _c are the pole pairs of the power motor and the control motor respectively.

The SVPWM pulse generator uses space vector pulse width modulation technology to generate three-phase PWM waves, and then controls the power converter on the control winding side to realize the control of the brushless doubly-fed generator.

The power converter on the control winding side adopts a three-phase full-bridge inverter circuit, and its output waveform has small harmonics, which is beneficial to the control of the brushless doubly-fed motor.

The experimental waveforms of a brushless doubly-fed motor feed-forward current control system described in this embodiment are shown in FIGS. 4-6 . In the feed-forward current controller, the control winding dq axis reference current i _cds ^* , i _cqs ^* with step change is applied. Figure 4 shows the control winding current in the dq coordinate system when the brushless doubly-fed motor is running at 400r/min ( i _cds , i _cqs ) and the three-phase static coordinate system (i _cas , i _cbs ) waveforms, the current frequency is 10Hz; Fig. 5 shows the dq coordinates of the control winding current when the brushless doubly-fed motor is running at 600r/min System (i _cds , i _cqs ) and three-phase stationary coordinate system (i _cas , i _cbs ), the current frequency is -10Hz (anti-phase sequence); Figure 6 shows the brushless doubly-fed motor running at 666r/ Waveform diagrams of the control winding current in the dq coordinate system (i _cds , i _cqs ) and the three-phase stationary coordinate system (i _cas , i _cbs ) in the min state, and the current frequency is -16.6Hz (anti-phase sequence).

It can be seen from the figure that the current rise time of the feed-forward current controller at different speeds is very short, and the controller can achieve a faster response with a smaller oscillation during the step change, which shows that the A brushless double-fed motor feed-forward current control system has good stability and dynamics at different operating speeds; the synchronous speed of the brushless double-fed motor is 500r/min, and when the speed is higher than 600r/min ( 120% synchronous speed), the traditional current controller has poor robustness, and even appears unstable, while the feed-forward current controller can still maintain good control performance when the speed increases to 666r/min (133% synchronous speed), stable The operating range is expanded from 120% to 133% of the synchronous speed, which shows that the feed-forward current control system can effectively expand the stable operating range of the brushless doubly-fed motor.

Claims (10)

1. a kind of brushless dual-feed motor feedforward current control system, it is characterised in that：The control system includes power grid (1), brushless Double feedback electric engine (2), the first converter (3), the second converter (4), flux linkage calculation module (5), angle calculation module (6), angle speed Spend computing module (7), photoelectric coded disk (8), feedforward current controller (9), third converter, the 4th converter (10), SVPWM Impulse generator (11), control winding side power inverter (12) and DC side (13)；

Wherein, the power winding of brushless dual-feed motor and control winding are connected respectively on power grid and power inverter, and power becomes The parallel operation other end is connected to DC side；The power winding of the input connection brushless dual-feed motor of first converter, before output connection Feed stream controller；The power winding of the input connection brushless dual-feed motor of second converter, output connection flux linkage calculation module； One output connection feedforward current controller of flux linkage calculation module, another output connect the first converter, another way all the way Angle calculation module is connected, third road passes through differentiator joint angle speed calculation module；The output of angular speed computing module connects Feedforward current controller；Photoelectric coded disk is mounted on brushless double-fed machine rotor, and the output of photoelectric coded disk is all the way by micro- Device joint angle speed calculation module, another way is divided to connect angle calculation module, the output of angle calculation module becomes with third respectively One input of parallel operation and the 4th converter is connected；The control winding of another input and brushless dual-feed motor of third converter Connection, output are connect with feedforward current controller；The output of feedforward current controller is connect with the 4th converter, the 4th transformation The output of device is connected with the input of SVPWM impulse generators, the output of SVPWM impulse generators and the input phase of power inverter Even.

2. a kind of brushless dual-feed motor feedforward current control system according to claim 1, it is characterised in that：The feedforward Current controller includes the first comparing unit (21), pi controller (22), the first feedforward compensation term (23), the second feedforward Compensation term (24), third feedforward compensation term (25), the second comparing unit (26) and third comparing unit (27), wherein the first ratio Compared with the input winding reference current vector i in order to control of unit_cs ^*With actual current vector i_cs, the output of the first comparing unit with than The input of example integral controller is connected, and the output of pi controller is connected with an input of the second comparing unit, third Feedforward compensation term as the second comparing unit another input, the output of the second comparing unit with one of third comparing unit Input is connected, other two input item of the first feedforward compensation term and the second feedforward compensation term as third comparing unit, third The output of comparing unit winding reference voltage vector u in order to control_cs ^*, power winding actual current vector i_psIt is mended as the first feedforward Repay the input of item, control winding actual current vector i_csInput as the second feedforward compensation term.

3. a kind of brushless dual-feed motor feedforward current control system according to claim 1, it is characterised in that：The magnetic linkage Numerical value u of the computing module acquisition power wound stator voltage in two-phase stationary coordinate system_pαsAnd u_pβs, and use u_pαsAnd u_pβsIt calculates The phase angle theta of power wound stator voltage_uAnd amplitude | u_s|：

According to the relationship of power wound stator voltage and magnetic linkage, the phase angle theta of power winding magnetic linkage is calculated_pWith amplitude ψ_p：

Wherein, ω_pFor the angular speed of power winding electricity.

4. a kind of brushless dual-feed motor feedforward current control system according to claim 1, it is characterised in that：The angle The rotor position angle θ that computing module is obtained by photoelectric coded disk and flux linkage calculation module_mWith power winding magnetic linkage phase angle theta_p, meter Calculation obtains the angle, θ of control winding electricity_c, relationship is between them：

θ_c=θ_p-(p_p+p_c)θ_m；

Wherein, p_pAnd p_cThe respectively number of pole-pairs of power motor and control motor.

5. a kind of brushless dual-feed motor feedforward current control system according to claim 1, it is characterised in that：The angle speed Spend the rotor position angle θ that computing module obtains photoelectric coded disk and flux linkage calculation module_mWith power winding magnetic linkage phase angle theta_pInto Rotor velocity ω is calculated in row differential_m, power winding electricity angular velocity omega_p：

Then according to control winding electricity angular velocity omega_cWith ω_m、ω_pRelationship, calculate ω_cSize, relationship between them For：

ω_c=ω_p-(p_p+p_c)ω_m；

Wherein, p_pAnd p_cThe respectively number of pole-pairs of power motor and control motor.

6. a kind of brushless dual-feed motor feedforward current control system according to claim 1, it is characterised in that：It is described SVPWM impulse generator use space Vector Pulse Width Modulation technologies generate three-phase PWM wave.

7. a kind of brushless dual-feed motor feedforward current control system according to claim 1, it is characterised in that：The control Winding side power inverter uses three-phase full-bridge inverting circuit.

8. a kind of feedforward current controller, it is characterised in that：Including the first comparing unit (21), pi controller (22), First feedforward compensation term (23), the second feedforward compensation term (24), third feedforward compensation term (25), the second comparing unit (26) and Three comparing units (27), wherein the input of the first comparing unit winding reference current vector i in order to control_cs ^*With actual current vector i_cs, the output of the first comparing unit is connected with the input of pi controller, the output of pi controller and the second ratio An input compared with unit is connected, another input of third feedforward compensation term as the second comparing unit, the second comparing unit Output be connected with an input of third comparing unit, the first feedforward compensation term and the second feedforward compensation term compare as third Other two input item of unit, the output of third comparing unit winding reference voltage vector u in order to control_cs ^*, power winding reality Current phasor i_psAs the input of the first feedforward compensation term, control winding actual current vector i_csAs the second feedforward compensation term Input.

9. a kind of feedforward current controller according to claim 8, it is characterised in that：First feedforward compensation term isIt includes first order inertial loops, wherein k₂=L_mc/L_mp, L_mc、L_mp、L_spRespectively in order to control The mutual inductance of winding, the mutual inductance of power winding, power winding self-induction, τ be first order inertial loop time constant, ω_cIn order to control Winding electricity angular speed, i_psFor power winding actual current vector, dq shaft current components are i_pdsAnd i_pqs；

Second feedforward compensation term is inductance feedforward term j ω_cL_sci_cs, L_scThe self-induction of winding in order to control, i_csWinding is real in order to control Border current phasor, dq shaft current components are i_cdsAnd i_cqs；

The third feedforward compensation term is magnetic flux feedforward term j ω_ck₂ψ_p, ψ_pFor power winding magnetic linkage amplitude.

10. a kind of method of any one of design claim 1-9 feedforward current controllers, which is characterized in that this method packet Include following steps：

(1) complete model of control winding current loop is built, complete model formula is：

(R_sc+sL_sc)i_cs(s)=u_cs(s)-k₂(s+jω_c)L_spi_ps(s)-jω_cL_sci_cs(s)+k₂(s+jω_c)ψ_p(s)；

Wherein, R_scThe resistance of winding in order to control, L_scThe self-induction of winding in order to control, u_csWinding virtual voltage vector in order to control, dq Axis component is u_cdsAnd u_cqs；k₂=L_mc/L_mp, L_mc、L_mp、L_spThe respectively mutual inductance of control winding, the mutual inductance of power winding, power The self-induction of winding, ω_cWinding electricity angular speed in order to control；i_psFor power winding actual current vector, dq axis components are i_pdsWith i_pqs；i_csWinding actual current vector in order to control, dq axis components are i_cdsAnd i_cqs；ψ_pFor power winding magnetic linkage amplitude；

(2) power winding actual current vector i is established_psWith control winding actual current vector i_csBetween coupled relation, coupling Closing relational expression is：

Wherein, k=L_mpL_mc/(L_spL_r'), k₁=L_r/L_r', L_rFor inductor rotor, L_r'=L_r-L_mp ²/L_spFor rotor transient inductance； And

Wherein, ω_mFor rotor speed, T_r' be rotor time constant, T_r'=L '_r/R_r, L '_r=L_r-L_mp ²/L_spFor rotor Transient inductance, R_rFor rotor resistance；

(3) coupled relation being based in the model and step (2) in step (1), builds the structure of control winding current loop, In, first order inertial loop G_RL(s)=1/ (R_sc+sL_sc) be control winding current loop core, current loop is there are two i_csInstead Branch is presented, branch I and branch II are expressed as, wherein branch I is i_psAnd i_csCoupling path between two electric currents, control Winding actual current vector i_csControl winding virtual voltage vector u is fed back to by two link in tandems_cs, respectively by k (1+G_r And k (s))₂L_sp(s+jω_c) indicate；Branch II is j ω_cL_sc；

(4) according to the structure of the control winding current loop in step (3), the compensation term of design feedforward current controller willAs feedforward term, branch I is equally cut off, is enabledAs first Feedforward compensation term, wherein k₂=L_mc/L_mp, L_mc、L_mp、L_spRespectively the mutual inductance of control winding, the mutual inductance of power winding, power around The self-induction of group, τ are the time constant of first order inertial loop, ω_cWinding electricity angular speed in order to control, i_psFor the practical electricity of power winding Flow vector, dq shaft current components are i_pdsAnd i_pqs；Second feedforward compensation term is inductance feedforward term j ω_cL_sci_cs, wherein L_scFor The self-induction of control winding, i_csWinding actual current vector in order to control, dq shaft current components are i_cdsAnd i_cqs；Third feedforward compensation Item is magnetic flux feedforward term j ω_ck₂ψ_p, wherein ψ_pFor power winding magnetic linkage amplitude.