CN103471499A - Detection method of initial position of permanent magnet synchronous motor rotor - Google Patents

Abstract

The invention relates to a detection method of an initial position of a permanent magnet synchronous motor rotor. The detection method comprises the following steps: injecting a three-phase symmetrical high-frequency rotary voltage signal into a detected motor stator winding when the motor is just started, thus obtaining an initial observation angle theta init; applying a direct-current voltage vector signal to an angle theta init direction, and recording a current value I1 and a corresponding time; applying the direct-current voltage vector signal to a direction of angle theta init plus 180 degrees, and recording a current value I2 and a corresponding time; calculating inductance values L1 and L2 in the angle theta init direction and the angle theta (init+80) degrees respectively by using formulas according to the recorded current values and the corresponding time; comparing the inductance values L1 and L2 in two angle directions, and taking a direction with a smaller inductance value as an initial position angle of a motor rotor. Through the method, the initial position of the permanent magnet synchronous motor rotor can be precisely calculated.

Description

The detection method of permanent-magnetic synchronous motor rotor initial position

Technical field

The present invention relates to motor detection technique field, particularly a kind of detection method of permanent-magnetic synchronous motor rotor initial position.

Background technology

Along with developing rapidly of permagnetic synchronous motor, the occupation rate of this motor in energy-conserving product is more and more higher.In some occasion, do not allow motor that scrambler is installed, so permagnetic synchronous motor more and more comes into one's own without the control method of sensor.Current permagnetic synchronous motor is that the method for back-emf estimation is calculated rotor magnetic pole position without the most use of sensor control method, but this method has its limitation because the low speed segment back-emf a little less than, sometimes can't observe at all.And said method general syllogic that adopts when electric motor starting starts, if do not set suitable starting current, motor probably starts failure.For above-mentioned reasons, current needs are developed a kind of control algolithm without sensor and can even under zero-speed, be observed rotor magnetic pole position at extremely low rotating speed.For the research of this respect, a lot of experts have proposed high-frequency signal injection, and this method can even be observed rotor magnetic pole position under zero-speed at extremely low rotating speed.The high-frequency signal injection ultimate principle is for applying the HF voltage of positive sequence to motor by inverter, then extract high-frequency current by bandpass filter, due to internal permanent magnet synchronous motor D, Q axle inductance difference, so also have the high-frequency current of inverted sequence except the high-frequency current of positive sequence, utilize digital filter that the high-frequency current of inverted sequence is extracted just to be resolved and can calculate rotor angle.High-frequency signal injection has obvious defect, is exactly when the detection rotor initial position, and output angle may have with actual angle the deviation of 180 °.If initial position detects inaccurate, motor can't start smoothly.So it is just very important to detect correct rotor angle.

Summary of the invention

The technical problem to be solved in the present invention is: overcome permagnetic synchronous motor rotor initial position in prior art and be difficult to the technical matters detected, a kind of detection method of permanent-magnetic synchronous motor rotor initial position is provided, but the initial position of method accurate Calculation permagnetic synchronous motor, make the smooth startup of permagnetic synchronous motor.

The technical solution adopted for the present invention to solve the technical problems is: a kind of detection method of permanent-magnetic synchronous motor rotor initial position has following steps:

Step 1, while just having been started by measured motor, to the amplitude of injecting voltage in tested motor stator winding, be the three-phase symmetrical high-frequency rotating voltage signal that U, angular frequency are ω, utilize high-frequency signal injection to obtain the angle of initial observation, be denoted as θ init, stop injecting three-phase symmetrical high-frequency rotating voltage signal;

Step 2, after waiting for 8-10ms, apply at θ init angle direction the DC voltage vector signal that amplitude is U, records at least two current value I ₁and the corresponding time, until electric current stops applying pulse voltage signal after approaching rated current;

Step 3, after waiting for 3-6ms, apply at θ init+180 ° angle direction the DC voltage vector signal that amplitude is U, records at least two current value I ₂and the corresponding time, until approaching rated current, electric current stops applying pulse voltage signal, after waiting for 3-6ms;

Step 4, according to the current value of record and corresponding time, utilize formula

calculate respectively the inductance value L at θ init and θ init+180 ° of two angle directions ₁and L ₂;

Step 5, relatively the inductance value L under θ init and θ init+180 ° of two angle direction ₁and L ₂, the initial position angle direction that the angle direction that inductance value is less is the rotor place.

Further, for improving accuracy and the reliability detected, record current value and the corresponding time of 20% rated current, 40% rated current, 60% rated current, 80% rated current, lower five points of 100% rated current in step 2 and 3, and calculate respectively the inductance value of corresponding these five points under two angles.

Further, improve the preparatory of judgement, be taken at the inductance L calculated under 20% rated current ₁with L ₂, calculate its difference ε ₁=L ₁-L ₂, calculating respectively by that analogy the difference in inductance Value Data under 40% rated current, 60% rated current, 80% rated current, 100% rated current, note is ε respectively ₂, ε ₃, ε ₄, ε ₅, these five difference data additions are obtained to ε=ε ₁+ ε ₂+ ε ₃+ ε ₄+ ε ₅, when be less than-a of ε, current θ init is the original position of electric motor's rotator angle, when ε is greater than a θ init+180 ° for the original position of electric motor's rotator angle, if | ε | during<a, detect unsuccessfully, get back to step 1 and again detect.

Due to formula

with the In function, inconvenience is resolved in digital control system, and the In function of formula in step 4 is calculated by Taylor series expansion, and Taylor expansion is as follows:

$\mathrm{<figure-callout\; id="1"\; label="ln"\; filenames="HDA0000394149490000012.png"\; state="\{\{state\}\}">ln</figure-callout>}\frac{1+x}{1-x}=2(x+\frac{1}{3}{x}^3+\frac{1}{5}{x}^5+...)(1<x<-1)$

Utilize above-mentioned formula to calculate respectively the inductance value L under θ init and θ init+180 ° of two angle direction ₁and L ₂.

As preferably, the frequency of described three-phase symmetrical high-frequency rotating voltage signal is 500-1000Hz, and amplitude U is 0.05 times of Alma Mater's voltage.

The invention has the beneficial effects as follows, the detection method of permanent-magnetic synchronous motor rotor initial position of the present invention, utilize high-frequency signal injection to calculate initial position of rotor, the method is simple and practical, also be easy to calculate, the computational solution precision aspect drawn is also comparatively desirable, and error is no more than 5 °, be conducive to the smooth startup of permagnetic synchronous motor, can meet most application scenario.

The accompanying drawing explanation

Below in conjunction with drawings and Examples, the present invention is further described.

Fig. 1 is the structured flowchart of the proving installation that adopts of the present invention;

Fig. 2 is the structured flowchart that the original position of electric motor's rotator that is built into of the present invention detects;

Fig. 3 be the internal permanent magnet synchronous motor rotor-position in the time of 0 °, the inductance value curve map of all directions;

Fig. 4 is control flow chart of the present invention.

Embodiment

In conjunction with the accompanying drawings, the present invention is further detailed explanation.These accompanying drawings are the schematic diagram of simplification, basic structure of the present invention only is described in a schematic way, so it only show the formation relevant with the present invention.

As Fig. 1, the pick-up unit of permanent-magnetic synchronous motor rotor initial position, for permagnetic synchronous motor is carried out to the detection of initial position of rotor, comprise D.C. regulated power supply, inverter, torque gauge and dynamometer machine, described D.C. regulated power supply and inverter form electric connection by wire, inverter and permagnetic synchronous motor form electric connection by wire, described torque gauge is installed on the output shaft of permagnetic synchronous motor, the output terminal dynamometer machine for connecting of torque gauge, inverter is the permagnetic synchronous motor power supply for D.C. regulated power supply being converted to alternating current, also for gathering the permagnetic synchronous motor current signal.

Before the experiment of detection rotor initial position, first build software control system, as shown in Figure 2, Fig. 2 comprise 1. the PARK inverse transform module, 2. the SVPWM conversion module, 3. inverter (Inverter), 4. resolve rotor angle module, 5. bandpass filter module, 6. CLAKE conversion module, 7. permagnetic synchronous motor.

The tested parameter of electric machine that the present invention adopts at the trial is as follows:

As shown in Figure 4, a kind of detection method of permanent-magnetic synchronous motor rotor initial position has following steps:

Step 1, while just having been started by measured motor, amplitude to injecting voltage in tested motor stator winding is the three-phase symmetrical high-frequency rotating voltage vector signal 200ms that U, angular frequency are ω, utilize high-frequency signal injection to obtain the angle of initial observation, be denoted as θ init, stop injecting three-phase symmetrical high-frequency rotating voltage signal; (annotate: the frequency of injection, voltage and time can suitably be adjusted along with different motors, for above-mentioned by the parameter of measured motor, the preferred three-phase symmetrical high-frequency rotating voltage of 500Hz, amplitude U is busbar voltage 0.05 times.）

Step 2, after waiting for 8-10ms, apply at θ init angle direction the DC voltage vector signal that amplitude is U, records at least two current value I 1 and corresponding time, until electric current stops applying pulse voltage signal after approaching rated current;

Step 3, after waiting for 3-6ms, apply at θ init+180 ° angle direction the DC voltage vector signal that amplitude is U, records at least two current value I ₂and the corresponding time, until approaching rated current, electric current stops applying pulse voltage signal, after waiting for 3-6ms; (annotate: the stand-by period can suitably be adjusted according to different motors.)

Step 4, according to the current value of record and corresponding time, utilize formula

calculate respectively the inductance value L at θ init and θ init+180 ° of two angle directions ₁and L ₂;

Step 5, relatively the inductance value L under θ init and θ init+180 ° of two angle direction ₁and L ₂, the initial position angle direction that the angle direction that inductance value is less is the rotor place.

Further, for improving accuracy and the reliability detected, record current value and the corresponding time of 20% rated current, 40% rated current, 60% rated current, 80% rated current, lower five points of 100% rated current in step 2 and 3, and calculate respectively the inductance value of corresponding these five points under two angles.

Further, improve the preparatory of judgement, be taken at the inductance L calculated under 20% rated current ₁with L ₂, calculate its difference ε ₁=L ₁-L ₂, calculating respectively by that analogy the difference in inductance Value Data under 40% rated current, 60% rated current, 80% rated current, 100% rated current, note is ε respectively ₂, ε ₃, ε ₄, ε ₅, these five difference data additions are obtained to ε=ε ₁+ ε ₂+ ε ₃+ ε ₄+ ε ₅, when be less than-a of ε, current θ init is the original position of electric motor's rotator angle, when ε is greater than a θ init+180 ° for the original position of electric motor's rotator angle, if | ε | during<a, detect unsuccessfully, get back to step 1 and again detect.

Due to formula

with the In function, inconvenience is resolved in digital control system, and the In function of formula in step 4 is calculated by Taylor series expansion, and Taylor expansion is as follows:

$\mathrm{<figure-callout\; id="1"\; label="ln"\; filenames="HDA0000394149490000012.png"\; state="\{\{state\}\}">ln</figure-callout>}\frac{1+x}{1-x}=2(x+\frac{1}{3}{x}^3+\frac{1}{5}{x}^5+...)(1<x<-1)$

Utilize above-mentioned formula to calculate respectively the inductance value L under θ init and θ init+180 ° of two angle direction ₁and L ₂.

As preferably, the frequency of described three-phase symmetrical high-frequency rotating voltage signal is 500-1000Hz, and amplitude U is 0.05 times of Alma Mater's voltage.

The origin of computing formula, motor equation under zero-speed:

$U=i*R+L*\frac{\mathrm{di}}{\mathrm{dt}}---\left(1\right)$

Formula (1) Laplace is converted

$I\left(s\right)=\frac{U\left(s\right)}{R}*\frac{1}{\frac{L}{R}*S+1}---\left(2\right)$

Formula (2) Laplace inverse transformation is obtained

$I=\frac{U}{R}(1-e^{-\frac{R*T}{L}})---\left(3\right)$

Formula (3) is arranged and can obtain

$L=\frac{-R*T}{\mathrm{In}(U-I*R)}---\left(4\right)$

In formula (4), U, R are known, and the current value I that substitution records and time T are obtained inductance value L.

As shown in Figure 3, for the internal permanent magnet synchronous motor rotor-position, 0 ° the time, the inductance of all directions is curve roughly.Can find out in the drawings, at 0 °, with 180 ° the time, inductance is less.Inductance when wherein the inductance in the time of 0 ° is slightly less than again 180 °.The reason of above-mentioned phenomenon is because the magnetic saturation degree of motor is the darkest on rotor direction, so inductance is less, so can utilize this phenomenon to carry out the detection rotor initial magnetic pole position.

The high-frequency signal injection adopted in step 1, be mainly used in the method that Speedless sensor servo-drive system speed is calculated, and is a kind of motor measuring method existing and commonly used.

The above-mentioned foundation desirable embodiment of the present invention of take is enlightenment, and by above-mentioned description, the relevant staff can, in the scope that does not depart from this invention technological thought, carry out various change and modification fully.The technical scope of this invention is not limited to the content on instructions, must determine its technical scope according to the claim scope.

Claims (5)

1. the detection method of a permanent-magnetic synchronous motor rotor initial position is characterized in that having following steps:

Step 1, while just having been started by measured motor, to the amplitude of injecting voltage in tested motor stator winding, be the three-phase symmetrical high-frequency rotating voltage signal that U, angular frequency are ω, utilize high-frequency signal injection to obtain the angle of initial observation, be denoted as θ init, stop injecting three-phase symmetrical high-frequency rotating voltage signal;

Step 2, after waiting for 8-10ms, apply at θ init angle direction the DC voltage vector signal that amplitude is U, records at least two current value I ₁and the corresponding time, until electric current stops applying pulse voltage signal after approaching rated current;

Step 3, after waiting for 3-6ms, apply at θ init+180 ° angle direction the DC voltage vector signal that amplitude is U, records at least two current value I ₂and the corresponding time, until approaching rated current, electric current stops applying pulse voltage signal, after waiting for 3-6ms;

Step 4, according to the current value of record and corresponding time, utilize formula

calculate respectively the inductance value L at θ init and θ init+180 ° of two angle directions ₁and L ₂;

Step 5, relatively the inductance value L under θ init and θ init+180 ° of two angle direction ₁and L ₂, the initial position angle direction that the angle direction that inductance value is less is the rotor place.

2. the detection method of permanent-magnetic synchronous motor rotor initial position as claimed in claim 1, it is characterized in that: record current value and the corresponding time of 20% rated current, 40% rated current, 60% rated current, 80% rated current, lower five points of 100% rated current in step 2 and 3, and calculate respectively the inductance value of corresponding these five points under two angles.

3. the detection method of permanent-magnetic synchronous motor rotor initial position as claimed in claim 2, is characterized in that: be taken at the inductance L calculated under 20% rated current ₁with L ₂, calculate its difference ε ₁=L ₁-L ₂, calculating respectively by that analogy the difference in inductance Value Data under 40% rated current, 60% rated current, 80% rated current, 100% rated current, note is ε respectively ₂, ε ₃, ε ₄, ε ₅, these five difference data additions are obtained to ε=ε ₁+ ε ₂+ ε ₃+ ε ₄+ ε ₅, when be less than-a of ε, current θ init is the original position of electric motor's rotator angle, when ε is greater than a θ init+180 ° for the original position of electric motor's rotator angle, if | ε | during<a, detect unsuccessfully, get back to step 1 and again detect.

4. the detection method of permanent-magnetic synchronous motor rotor initial position as claimed in claim 1 is characterized in that:

The In function of formula in step 4 is calculated by Taylor series expansion, and Taylor expansion is as follows:

$\ln \frac{1+x}{1-x}=2(x+\frac{1}{3}{x}^3+\frac{1}{5}{x}^5+...)(1<x<-1)$

Utilize above-mentioned formula to calculate respectively the inductance value L under θ init and θ init+180 ° of two angle direction ₁and L ₂.

5. the detection method of permanent-magnetic synchronous motor rotor initial position as claimed in claim 1, it is characterized in that: the frequency of described three-phase symmetrical high-frequency rotating voltage signal is 500-1000Hz, amplitude U is 0.05 times of Alma Mater's voltage.

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