CN102751933B - A kind of motor torque lifting device and method - Google Patents

Abstract

The present invention discloses a kind of motor torque lifting device and method, comprises the frequency converter be connected with motor, and described frequency converter includes current sampling unit, and inverter control unit and voltage compensation adjuster AUR, by the stator current vector of described motor stator voltage vector with given instruction voltage-mode value U _ref, as the input of described voltage compensation adjuster AUR, after this voltage compensation adjuster AUR regulates, obtain described given instruction voltage-mode value U _refvoltage compensation quantity U _rs, by formula U ' _ref=U _ref+ U _rs, calculate compensation rate U with voltage _rsnew command voltage modulus value U ' _ref, U ' _refas the controlled quentity controlled variable of described inverter control unit; By the stator current vector of motor stator voltage vector given instruction voltage-mode value U _refwith recognize stator resistance R _s, go out given instruction voltage-mode value U through voltage compensation adjuster AUR real-time operation _refvoltage compensation quantity U _rs, and then obtain the given instruction voltage-mode value U ' of compensation rate with voltage _ref.Dynamic of the present invention compensates the amount of pressure drop on stator, makes output current more level and smooth and has good running frequency change adaptivity.

Description

A kind of motor torque lifting device and method

Technical field

The present invention relates to motor control technology field, be specifically related to a kind of novel frequency converter torque magnification device and method.

Background technology

The development of universal frequency converter is very rapid, applies increasingly extensive.Use the drive system of frequency converter, energy-conservation, enhance productivity, aspect of improving the quality of products possesses advantage.Thus, in production practices, just giving play to increasing effect.

At present, a large amount of V/f frequency converter used in blower fan, water pump application, although can meet the needs of most of production process, its load capacity when low frequency is often not fully up to expectations.In such cases, there has been proposed and increase torque magnification function in V/f frequency converter, the amount of pressure drop on the most directly compensated setpoint stator resistance of this type of function, and then increase magnetic flux, improve load capacity.But for most of frequency converter control system, even if used such torque magnification function, in 1.5 times of loaded starting processes, also usually cannot normally work: the amount of pressure drop on compensated setpoint stator resistance is little, band carries and cannot start; Amount of pressure drop on compensated setpoint stator resistance is large, direct overcurrent in loaded starting process.Even if under a certain running frequency, have found comparatively suitable value complement and repay amount of pressure drop on stator resistance, motor is successfully with and is carried.But along with the change of running frequency, its value also can no longer adapt to, need again to find, this is just in different running frequency section, and the amount of pressure drop that given suitable value complement is repaid on stator resistance brings trouble.Therefore, in starting process, how to make compensation rate make self-adaptative adjustment with the change of amount of pressure drop on stator resistance, become and be even more important.

Therefore; how to design a kind of in starting process according to the pressure drop on stator; amount of pressure drop on dynamic compensation stator; thus effectively promote the method for torque; the method makes output current more level and smooth and has good running frequency change adaptivity; improving torque characteristics and can motor protected, becoming the direction that those skilled in the art make great efforts.

Summary of the invention

The object of the invention is to provide a kind of motor torque lifting device and method, its in starting process the method according to the pressure drop on stator, the amount of pressure drop on dynamic compensation stator, thus the method effectively promoting torque; And make output current more level and smooth and have good running frequency change adaptivity, improve torque characteristics, also protect motor.

For achieving the above object, the technical solution used in the present invention is: motor torque lifting device, comprise the frequency converter be connected with motor, described frequency converter includes current sampling unit, inverter control unit and voltage compensation adjuster AUR, by the stator current vector of described motor stator voltage vector with given instruction voltage-mode value U _ref, as the input of described voltage compensation adjuster AUR, after this voltage compensation adjuster AUR regulates, obtain described given instruction voltage-mode value U _refvoltage compensation quantity U _rs, by formula U ' _ref=U _ref+ U _rs, calculate compensation rate U with voltage _rsnew command voltage modulus value U ' _ref, U ' _refas the output voltage control instruction of described inverter control unit.

The technical scheme improved further in technique scheme is as follows:

1, in such scheme, by voltage compensation, described voltage compensation adjuster AUR estimates that PI controller and feedback voltage estimate that device forms, and wherein, this feedback voltage estimation device is by the stator current vector of described motor and stator voltage vector calculate stator vector voltage deduct Stator resistance voltage dropping after feedback voltage estimated value E, described voltage compensation estimation PI controller is by stator vector voltage deduct Stator resistance voltage dropping after feedback voltage estimated value E and given instruction voltage-mode value U _reftwo inputs, calculate described given instruction voltage-mode value U _refvoltage compensation quantity U _rs.

2, in such scheme, described feedback voltage estimated value E is by stator current vector $\stackrel{\→}{I}=\left[\begin{array}{c}\mathrm{Ialfa}\\ \mathrm{Ibeta}\end{array}\right],$ Stator voltage vector $\stackrel{\→}{U}=\left[\begin{array}{c}\mathrm{Ualfa}\\ \mathrm{Ubeta}\end{array}\right],$ Stator resistance voltage dropping ${\stackrel{\→}{U}}_{R_s}=\left[\begin{array}{c}{R}_s\·\mathrm{Ialfa}\\ R_s\·\mathrm{Ibeta}\end{array}\right]$ With stator resistance R _s, pass through formula $E=\sqrt{{(\mathrm{Ubeta}-R_s\·\mathrm{Ibeta})}^2+{(\mathrm{Ualfa}-R_s\·\mathrm{Ialfa})}^2}$ Described feedback voltage estimated value E is obtained after computing.

Be applied to an above-mentioned motor torque method for improving, comprise following concrete steps:

Step 1: after frequency converter receives action command, first passes into a certain amount of DC pre-excitation electric current and carries out pre-excitation to motor;

Step 2: after DC pre-excitation current stabilization, by pre-excitation electric current and motor stator voltage, with voltammetry identification stator resistance R _s;

Step 3: recognize stator resistance R _safter transfer normal operating condition to, in this case, by the stator current vector of motor stator voltage vector given instruction voltage-mode value U _refwith the stator resistance R recognized _s, go out given instruction voltage-mode value U through voltage compensation adjuster AUR real-time operation _refvoltage compensation quantity U _rs, and then obtain the new command voltage modulus value U ' of compensation rate with voltage _refi.e. formula U ' _ref=U _ref+ U _rs, U ' _refas the output voltage control instruction of inverter controller.。

Because technique scheme is used, the present invention compared with prior art has following advantages and effect:

Motor torque lifting device of the present invention and method, according to the pressure drop on stator in starting process, the amount of pressure drop on dynamic compensation stator, reduces the complexity using torque magnification greatly, thus effectively promotes the method for torque, torque magnification successful during starting; The method makes output current more level and smooth and has good running frequency change adaptivity, and improving torque characteristics, there is realistic meaning widely protection motor aspect; Secondly, during the present invention runs, current curve is level and smooth, and during low frequency, mechanical property improves.Accompanying drawing explanation

Accompanying drawing 1 is electrical principle block diagram of the present invention;

Accompanying drawing 2 is electrical schematic diagram of the present invention;

Accompanying drawing 3 is resolution chart of the present invention.

Embodiment

Below in conjunction with drawings and Examples, the invention will be further described:

As shown in Figure 1: a kind of motor torque lifting device, comprises the frequency converter be connected with motor, and described frequency converter includes current sampling unit, inverter control unit and voltage compensation adjuster AUR, by the stator current vector of described motor stator voltage vector with given instruction voltage-mode value U _ref, as the input of described voltage compensation adjuster AUR, after this voltage compensation adjuster AUR regulates, obtain described given instruction voltage-mode value U _refvoltage compensation quantity U _rs, by formula U ' _ref=U _ref+ U _rs, calculate compensation rate U with voltage _rsnew command voltage modulus value U ' _ref, U ' _refas the output voltage control instruction of described inverter control unit.

By voltage compensation, above-mentioned voltage compensation adjuster AUR estimates that PI controller and feedback voltage estimate that device forms, wherein, this feedback voltage estimation device is by the stator current vector of described motor and stator voltage vector calculate stator voltage vector deduct Stator resistance voltage dropping after feedback voltage estimated value E, described voltage compensation estimation PI controller is by stator vector voltage deduct Stator resistance voltage dropping after feedback voltage estimated value E and given instruction voltage-mode value U _reftwo inputs, calculate described given instruction voltage-mode value U _refvoltage compensation quantity U _rs.

Above-mentioned feedback voltage estimated value E is by stator current vector $\stackrel{\→}{I}=\left[\begin{array}{c}\mathrm{Ialfa}\\ \mathrm{Ibeta}\end{array}\right],$ Stator voltage vector $\stackrel{\→}{U}=\left[\begin{array}{c}\mathrm{Ualfa}\\ \mathrm{Ubeta}\end{array}\right],$ Stator resistance voltage dropping ${\stackrel{\→}{U}}_{R_s}=\left[\begin{array}{c}{R}_s\·\mathrm{Ialfa}\\ R_s\·\mathrm{Ibeta}\end{array}\right]$ With stator resistance R _s, pass through formula $E=\sqrt{{(\mathrm{Ubeta}-R_s\·\mathrm{Ibeta})}^2+{(\mathrm{Ualfa}-R_s\·\mathrm{Ialfa})}^2}$ Described feedback voltage estimated value E is obtained after computing.

Be applied to an above-mentioned motor torque method for improving, comprise following concrete steps:

Step 1: after frequency converter receives action command, first passes into a certain amount of DC pre-excitation electric current and carries out pre-excitation to motor;

Step 2: after DC pre-excitation current stabilization, by pre-excitation electric current and motor stator voltage, with voltammetry identification stator resistance R _s;

Step 3: recognize stator resistance R _safter transfer normal operating condition to, in this case, by the stator current vector of motor stator voltage vector given instruction voltage-mode value U _refwith the stator resistance R recognized _s, go out given instruction voltage-mode value U through voltage compensation adjuster AUR real-time operation _refvoltage compensation quantity U _rs, and then obtain the new command voltage modulus value U ' of compensation rate with voltage _refi.e. formula U ' _ref=U _ref+ U _rs, U ' _refas the output voltage control instruction of inverter controller.

Whole process is primarily of identification stator resistance, and according to sampled output current, voltage, compensates the pressure drop composition on stator.

In given voltage U _outsize is the DC quantity of 0.3% of rated voltage, sampled output current I _outfor 3.8A, through equation

$R_s=\frac{U_{\mathrm{out}}}{I_{\mathrm{out}}}$

Calculate the stator resistance R of motor _sbe 0.3 Europe.

As shown in Figure 2, motor torque lifting device and method, comprise the frequency converter be connected with motor, and described frequency converter includes current sampling unit, and inverter control unit and voltage compensation adjuster AUR form; Wherein, inverter control unit includes polar coordinates to two-phase conversion module (PCoordToStatic), space vector modulation module (SVG) and inversion module (Invertor), and voltage compensation adjuster AUR includes voltage compensation estimation PI controller and feedback voltage estimation device.Go out stator vector voltage deduct amount of pressure drop on stator resistance according to above-mentioned voltage, current operator magnitude of voltage E afterwards, then according to given instruction voltage-mode value U _refand the error between E calculates the voltage-drop compensation amount U on stator resistance by pi regulator _rs, new command voltage modulus value U ' _reffor the voltage-drop compensation amount U on stator _rswith given instruction voltage-mode value U _refsum, U ' _refas the output voltage control instruction of described inverter control unit.

As shown in Figure 3: be with 1.5 times to carry when VF pattern opens this function and start waveform, visible motor normal starting, electric current smoothly declines after reaching 2 times of rated current, is finally stabilized in 1.5 times of rated current places.Waveform is good, and successful, reaches the initial requirement of conceptual design.

The present embodiment foregoing is further described below.

One is applied to above-mentioned motor torque method for improving, and described method comprises the frequency converter be connected with motor, and described frequency converter includes current sampling unit, inverter control unit and voltage compensation adjuster AUR; Wherein, inverter control unit includes polar coordinates to two-phase conversion module (PCoordToStatic), space vector modulation module (SVG) and inversion module (Invertor), and voltage compensation adjuster AUR includes voltage compensation estimation PI controller and feedback voltage estimation device.The input of current signal Ialfa and Ibeta as feedback voltage estimation device in voltage compensation adjuster AUR is obtained by current sampling unit; Polar coordinates in inverter control unit to two-phase conversion module (PCoordToStatic) output Ualfa and Ubeta as in voltage compensation adjuster AUR feedback voltage estimation device input; In voltage compensation adjuster AUR, the output E of feedback voltage estimation device estimates the input of PI controller as voltage compensation in voltage compensation adjuster AUR, given instruction voltage-mode value U _refas another input of voltage compensation estimation PI controller in voltage compensation adjuster AUR; In voltage compensation adjuster AUR, voltage compensation estimates the output of PI controller and given instruction voltage-mode value U _refbe added with U ' _refas the input of the polar coordinates in inverter control unit to two-phase conversion module (PCoordToStatic); Given anglec of rotation angle is as another input to two-phase conversion module (PCoordToStatic) of the polar coordinates in inverter control unit; Polar coordinates in inverter control unit to output Ualfa and Ubeta of two-phase conversion module (PCoordToStatic) as the input of the space vector modulation module (SVG) in inverter control unit; Output Ta, Tb, the Tc of space vector modulation module (SVG) in inverter control unit are as the input of inversion module in inverter control unit (Invertor); In inverter control unit, output Ua, Ub, Uc of inversion module (Invertor) are as the input of motor; Output Ia, Ib, Ic of motor are as the input of current sampling unit.

Said method comprising the steps of:

Step 1: after frequency converter receives action command, first passes into a certain amount of DC pre-excitation electric current and carries out pre-excitation;

Step 2: after DC pre-excitation current stabilization, by pre-excitation electric current and stator voltage, with voltammetry identification stator resistance R _s;

Step 3: recognize stator resistance R _safter transfer normal operating condition to;

Step 4: the stator current vector of motor clark conversion through current sampling unit obtains the input of current signal Ialfa and Ibeta as feedback voltage estimation device in voltage compensation adjuster AUR;

Step 5: according to the polar coordinates in inverter control unit to output Ialfa, Ibeta of output Ualfa, Ubeta of two-phase conversion module (PCoordToStatic) and current sampling unit and formula $E=\sqrt{{(\mathrm{Ubeta}-R_s\·\mathrm{Ibeta})}^2+{(\mathrm{Ualfa}-R_s\·\mathrm{Ialfa})}^2},$ Calculate the output E of feedback voltage estimation device in voltage compensation adjuster AUR;

Step 6: according to output E and the given instruction voltage-mode value U of feedback voltage estimation device in voltage compensation adjuster AUR _ref, in voltage compensation adjuster AUR, voltage compensation estimation PI controller, calculates given instruction voltage-mode value U _refvoltage compensation quantity U _rs.

Step 7: according to the output U of voltage compensation estimation PI controller in voltage compensation adjuster AUR _rswith given instruction voltage-mode value U _ref, carry out sum operation and for U ' _ref, i.e. formula U ' _ref=U _rs+ U _ref;

Step 8: according to the U ' of step 7 _refwith given anglec of rotation angle, the polar coordinates in inverter control unit export Ualfa, Ubeta to two-phase conversion module (PCoordToStatic) transform operation;

Step 9: according to Ualfa, Ubeta of step 8, the space vector modulation module (SVG) in the inverter control unit in inverter control unit, modulation exports Ta, Tb, Tc;

Step 10: according to Ta, Tb, Tc of step 9, in inverter control unit, inversion module (Invertor) exports Ua, Ub, Uc to motor.

The described Clark conversion of above-mentioned steps 4 is realized by following formula:

$\left[\begin{array}{c}\mathrm{Ialfa}\\ \mathrm{Ibeta}\end{array}\right]=\sqrt{2/3}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{2}\\ \frac{1}{\sqrt{2}}& \frac{1}{\sqrt{2}}& \frac{1}{\sqrt{2}}\end{array}\right]\left[\begin{array}{c}\mathrm{Ia}\\ \mathrm{Ib}\\ \mathrm{Ic}\end{array}\right]$

The described conversion of above-mentioned steps 8 is realized by following formula:

$\left[\begin{array}{c}\mathrm{Ualfa}\\ \mathrm{Ubeta}\end{array}\right]=\left[\begin{array}{c}{U}_{\mathrm{ref}}^{\′}\·\cos \left(\mathrm{angle}\right)\\ U_{\mathrm{ref}}^{\′}\·\sin \left(\mathrm{angle}\right)\end{array}\right]$

Above-described embodiment, only for technical conceive of the present invention and feature are described, its object is to person skilled in the art can be understood content of the present invention and implement according to this, can not limit the scope of the invention with this.All equivalences done according to Spirit Essence of the present invention change or modify, and all should be encompassed within protection scope of the present invention.

Claims (3)

1. a motor torque lifting device, comprises the frequency converter be connected with motor, and described frequency converter includes current sampling unit, inverter control unit and voltage compensation adjuster AUR, it is characterized in that: by the stator current vector of described motor stator voltage vector with given instruction voltage-mode value U _ref, as the input of described voltage compensation adjuster AUR, after this voltage compensation adjuster AUR regulates, obtain described given instruction voltage-mode value U _refvoltage compensation quantity U _rs, by formula U ' _ref=U _ref+ U _rs, calculate compensation rate U with voltage _rsnew command voltage modulus value U ' _ref, U ' _refas the output voltage control instruction of described inverter control unit; By voltage compensation, described voltage compensation adjuster AUR estimates that pi regulator and feedback voltage estimate that device forms, feedback voltage estimated value E is by stator current vector $\stackrel{r}{I}=\left[\begin{array}{c}\mathrm{Ialfa}\\ \mathrm{Ibeta}\end{array}\right],$ Stator voltage vector $\stackrel{r}{U}=\left[\begin{array}{c}\mathrm{Ualfa}\\ \mathrm{Ubeta}\end{array}\right],$ Stator resistance voltage dropping ${\stackrel{r}{R}}_{\mathrm{Rs}}=\left[\begin{array}{c}{R}_s\·\mathrm{Ialfa}\\ R_s\·\mathrm{Ibeta}\end{array}\right]$ With stator resistance R _s, pass through formula $E=\sqrt{{(\mathrm{Ubeta}-R_s\·\mathrm{Ibeta})}^2+{(\mathrm{Ualfa}-R_s\·\mathrm{Ialfa})}^2}$ Feedback voltage estimated value E is obtained after computing.

2. motor torque lifting device according to claim 1, it is characterized in that: by voltage compensation, described voltage compensation adjuster AUR estimates that PI controller and feedback voltage estimate that device forms, wherein, this feedback voltage estimation device is by the stator current vector of described motor and stator voltage vector calculate stator vector voltage deduct Stator resistance voltage dropping after feedback voltage estimated value E, described voltage compensation estimation PI controller is by stator vector voltage deduct Stator resistance voltage dropping after feedback voltage estimated value E and given instruction voltage-mode value U _reftwo inputs, calculate described given instruction voltage-mode value U _refvoltage compensation quantity U _rs.

3. be applied to a method for the motor torque lifting device of described claim 1, it is characterized in that: comprise following concrete steps:

This motor torque lifting device comprises the frequency converter be connected with motor, and described frequency converter includes current sampling unit, inverter control unit and voltage compensation adjuster AUR, it is characterized in that: by the stator current vector of described motor stator voltage vector with given instruction voltage-mode value U _ref, as the input of described voltage compensation adjuster AUR, after this voltage compensation adjuster AUR regulates, obtain described given instruction voltage-mode value U _refvoltage compensation quantity U _rs, by formula U ' _ref=U _ref+ U _rs, calculate compensation rate U with voltage _rsnew command voltage modulus value U ' _ref, U ' _refas the output voltage control instruction of described inverter control unit; By voltage compensation, described voltage compensation adjuster AUR estimates that pi regulator and feedback voltage estimate that device forms, described feedback voltage estimated value E is by stator current vector $\stackrel{r}{I}=\left[\begin{array}{c}\mathrm{Ialfa}\\ \mathrm{Ibeta}\end{array}\right],$ Stator voltage vector $\stackrel{r}{U}=\left[\begin{array}{c}\mathrm{Ualfa}\\ \mathrm{Ubeta}\end{array}\right],$ Stator resistance voltage dropping ${\stackrel{r}{U}}_{\mathrm{Rs}}=\left[\begin{array}{c}{R}_s\·\mathrm{Ialfa}\\ R_s\·\mathrm{Ibeta}\end{array}\right]$ With stator resistance R _s, pass through formula $E=\sqrt{{(\mathrm{Ubeta}-R_s\·\mathrm{Ibeta})}^2+{(\mathrm{Ualfa}-R_s\·\mathrm{Ialfa})}^2}$ Feedback voltage estimated value E is obtained after computing;

Step 1: after frequency converter receives action command, first passes into a certain amount of DC pre-excitation electric current and carries out pre-excitation to motor;

Step 2: after DC pre-excitation current stabilization, by pre-excitation electric current and motor stator voltage, with voltammetry identification stator resistance R _s;

Step 3: recognize stator resistance R _safter transfer normal operating condition to, in this case, by the stator current vector of motor stator voltage vector given instruction voltage-mode value U _refwith the stator resistance R recognized _s, go out given instruction voltage-mode value U through voltage compensation adjuster AUR real-time operation _refvoltage compensation quantity U _rs, and then obtain the new command voltage modulus value U ' of compensation rate with voltage _refi.e. formula U ' _ref=U _ref+ U _rs, U ' _refas the output voltage control instruction of inverter control unit.