CN111030546A - Permanent magnet motor offline parameter identification method and device - Google Patents
Permanent magnet motor offline parameter identification method and device Download PDFInfo
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- CN111030546A CN111030546A CN201911317034.2A CN201911317034A CN111030546A CN 111030546 A CN111030546 A CN 111030546A CN 201911317034 A CN201911317034 A CN 201911317034A CN 111030546 A CN111030546 A CN 111030546A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/14—Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
- H02P25/022—Synchronous motors
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- Control Of Ac Motors In General (AREA)
Abstract
The invention discloses a permanent magnet motor offline parameter identification method and a device, wherein the method comprises the following steps: excitation amplitude U determining step and voltage drop compensation VfA determination step and a parameter calculation step. The invention applies step voltage to the permanent magnet motor, and calculates the voltage drop compensation V through an approximate modelfThe actual voltage of the motor coil is calculated according to the value, and then parameter identification is carried out, and compared with the existing method that a detection circuit is additionally arranged to measure the actual voltage of the motor coil and an observer is used to adjust parameters, the method has the advantages of low cost and convenience in implementation.
Description
Technical Field
The invention relates to the field of motor control, in particular to a permanent magnet motor offline parameter identification method and device.
Background
With the rapid development of power electronic technology, microelectronic technology and permanent magnet material technology and the continuous deepening of control theory research, the servo control system of the alternating current permanent magnet synchronous motor is widely applied by virtue of the advantages of small volume, light weight, superior speed regulation performance and the like. In practical applications, the resistance and inductance parameters of the permanent magnet synchronous motor are very important for the parameter calculation of a PI (proportional integral) controller.
In the process of identifying the off-line parameters of the permanent magnet motor, because the excitation voltage actually applied to the motor coil has a voltage difference with the command voltage, in order to accurately obtain the actual excitation voltage value on the motor coil, a voltage detection circuit is generally added on a servo driver or a voltage observer is designed to measure and estimate the actual excitation voltage, so as to further realize the identification of the motor parameters. However, the method of adding the voltage measurement circuit increases the cost of the servo driver, and the parameter adjustment of the observer is generally complicated and not easy to converge.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides the permanent magnet motor offline parameter identification method which is simple and can effectively reduce the permanent magnet motor parameter identification cost.
The invention further provides a permanent magnet motor parameter identification device.
In a first aspect, an embodiment of the present invention provides a permanent magnet motor offline parameter identification method: the method comprises the following steps:
determining an excitation amplitude U;
pressure drop compensation VfA determination step: the method comprises the following steps: locking the permanent magnet motor to an electrical angle zero position;
step voltage is applied to the permanent magnet motor, and the amplitude of the voltage is gradually increased until the value of the U-phase current reaches a first preset point current value Iu1And a second preset point current value Iu2Recording the corresponding first preset point voltage value Uα1And a second preset point voltage value Uα2；
Applying voltage to the permanent magnet motor, and recording the voltage value U when the voltage amplitude is a first preset pointα1And a second preset point voltage value Uα2Corresponding first current value I'u1And a second current value I'u2；
The first current value I'u1And the second current value I'u2The first preset point voltage value Uα1And said second preset point voltage value Uα2Substituting into formula
Calculating to obtain the voltage drop compensation V of the permanent magnet motorfAnd said permanent magnetA motor armature resistance value R';
and (3) parameter calculation: applying a voltage U (k) to the permanent magnet motor, wherein the amplitude of the voltage U (k) is equal to the excitation amplitude U within an error range, and recording the working current I (k) of the permanent magnet motor at the moment;
will correct voltage U'(k)Substituting the working current I (k) into a preset model, and correcting the voltage U'(k)Equal to U (k) -VfAnd k is a measurement serial number, and the offline parameters of the permanent magnet motor are calculated.
The permanent magnet motor offline parameter identification method provided by the embodiment of the invention at least has the following beneficial effects: applying step voltage to the permanent magnet motor, and calculating voltage drop compensation V through an approximate modelfThe actual voltage of the motor coil is calculated according to the value, and then parameter identification is carried out, and compared with the existing method that a detection circuit is additionally arranged to measure the actual voltage of the motor coil and an observer is used to adjust parameters, the method has the advantages of low cost and convenience in implementation.
Further, the excitation amplitude U determining step includes:
and applying voltage to the permanent magnet motor, and gradually increasing the amplitude of the voltage until the working current of the permanent magnet motor reaches the rated current value of 100%, wherein the voltage amplitude at the moment is the excitation amplitude U.
Further, the first preset point current value Iu1Equal to 80% of the rated current value of the permanent magnet motor, and the second preset point current value Iu2Equal to 90% of the rated current value of the permanent magnet motor.
Further, the preset model comprises a recursive least square method model or a least square method model.
Further, the recursion formula of the recursion least square method model is Iout(k)＝-aIout(k-1) + bU (k-1), wherein Iout(k) And the measured value is the kth output current of the permanent magnet motor, U (k-1) is the measured value of the (k-1) th motor coil voltage of the permanent magnet motor, and a and b are correlation coefficients.
Further, the parameters of the permanent magnet motor include an equivalent resistance R and an equivalent inductance L, and
t is the sampling period of the discrete domain.
In a second aspect, an embodiment of the present invention provides a permanent magnet motor parameter identification apparatus, including:
an excitation amplitude identification module: the excitation voltage is used for calculating the excitation voltage in the offline parameter identification process of the permanent magnet motor;
pressure drop compensation VfA calculation module: for calculating an actual voltage drop of the permanent magnet motor;
a parameter identification module: for calculating parameters of the permanent magnet machine.
The permanent magnet motor parameter identification device provided by the embodiment of the invention at least has the following beneficial effects: the method is beneficial to parameter adjustment of the permanent magnet motor and low in cost.
According to other embodiments of the invention, the permanent magnet motor parameter identification device is a permanent magnet motor parameter identification device, and the voltage drop compensation V is a voltage drop compensationfThe calculation module comprises:
an excitation power supply control unit: the excitation voltage is used for applying a preset amplitude value to the permanent magnet motor;
a current sampling unit: the device is used for measuring the working current of the permanent magnet motor;
an arithmetic unit: for calculating the pressure drop compensation V according to a predetermined modelf。
Drawings
Fig. 1 is a schematic flow chart of an embodiment of a permanent magnet motor offline parameter identification method according to the present invention;
fig. 2 is a schematic structural diagram of an embodiment of an offline parameter identification device for a permanent magnet motor according to the present invention.
Detailed Description
The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.
In the description of the present invention, if an orientation description is referred to, for example, the orientations or positional relationships indicated by "upper", "lower", "front", "rear", "left", "right", etc. are based on the orientations or positional relationships shown in the drawings, only for convenience of describing the present invention and simplifying the description, but not for indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. If a feature is referred to as being "disposed," "secured," "connected," or "mounted" to another feature, it can be directly disposed, secured, or connected to the other feature or indirectly disposed, secured, connected, or mounted to the other feature.
In the description of the embodiments of the present invention, if "a number" is referred to, it means one or more, if "a plurality" is referred to, it means two or more, if "greater than", "less than" or "more than" is referred to, it is understood that the number is not included, and if "greater than", "lower" or "inner" is referred to, it is understood that the number is included. If reference is made to "first" or "second", this should be understood to distinguish between features and not to indicate or imply relative importance or to implicitly indicate the number of indicated features or to implicitly indicate the precedence of the indicated features.
Referring to fig. 1, a schematic flow chart of an offline parameter identification method for a permanent magnet motor in an embodiment of the present invention is shown. The method specifically comprises the following steps:
determining an excitation amplitude U;
pressure drop compensation VfA determination step;
and (5) calculating parameters.
Wherein the pressure drop is compensated by VfThe determining step includes: locking the permanent magnet motor to an electrical angle zero position;
applying a voltage to the permanent magnet motor and gradually increasing the amplitude of the voltage until the value of the U-phase current reachesTo a first preset point current value Iu1And a second preset point current value Iu2Recording the corresponding first preset point voltage value Uα1And a second preset point voltage value Uα2；
Applying voltage to the permanent magnet motor, and recording the voltage value U when the voltage amplitude is a first preset pointα1And a second preset point voltage value Uα2Corresponding first current value I'u1And a second current value I'u2；
Because the current sampling value has certain fluctuation, in order to obtain more accurate test effect, the first preset point voltage value U is reapplied to the permanent magnet motorα1And a second preset point voltage value Uα2First current value I'u1And a second current value I'u2Is the average of multiple observations.
A first current value I'u1And a second current value I'u2A first preset point voltage value Uα1And a second preset point voltage value Uα2Substituting equation 1:
calculating to obtain the voltage drop compensation V of the permanent magnet motorfAnd the armature resistance value R' of the permanent magnet motor.
The parameter calculation step comprises: applying voltage U (k) to the permanent magnet motor, wherein the amplitude of the voltage U (k) is equal to the excitation amplitude U within an error range, and recording the working current I (k) of the permanent magnet motor at the moment;
will correct voltage U'(k)Correcting voltage U 'by substituting operating current I (k) into preset model'(k)Equal to U (k) -VfAnd k is a measurement serial number, and the offline parameters of the permanent magnet motor are calculated.
The specific principle is as follows: due to the excitation of the input voltage, i.e. the first predetermined point voltage value Uα1And a second preset point voltage value Uα2Small, the duty cycle of the effective voltage is small, so the voltage drop compensation VfCan be approximated as a constant, and the voltage drop compensation V can be calculated by solving the equation systemf。
In the parameter identification process of the permanent magnet motor, step voltage is applied to the permanent magnet motor, and voltage drop compensation V is calculated through an approximate modelfThe actual voltage of the motor coil is obtained through the value, and compared with the existing method that a detection circuit is additionally arranged to measure the actual voltage of the motor coil and an observer is used to adjust parameters, the method has the advantages of low cost and convenience in implementation.
Specifically, the first preset point current value Iu1Equal to 80% of the rated current value of the permanent magnet motor, and the second preset point current value Iu2Equal to 90% of the rated current value of the permanent magnet motor, it should be noted that the first preset point current value Iu1And a second preset point current value Iu2Not limited to the two values, the pre-set point current value should be closer to the nominal current value in order to obtain a more accurate parameter estimation value.
In the parameter identification process, if the excitation voltage is too small, the noise of the test result is large, and if the excitation voltage is too large, the motor may be burnt out, so that a proper excitation voltage amplitude needs to be selected.
The excitation amplitude U determining step specifically comprises the following steps: and applying voltage to the permanent magnet motor, and gradually increasing the amplitude of the voltage until the working current of the permanent magnet motor reaches the rated current value of 100%, wherein the voltage amplitude at the moment is the excitation amplitude U, and the motor can be prevented from being burnt out by gradually increasing the amplitude of the excitation voltage, and the excitation voltage can be ensured to be large enough to reduce the noise of the result.
The preset model in the parameter calculation step comprises a recursive least square model or a least square model.
The ideal transfer function model of the armature can be approximated to a first-order inertia link, and in the servo driver, the servo system is actually a discrete system taking the interrupt period of the main control chip as a step length, so that the recursion formula of the recursion least square method model is as follows:
Iout(k)＝-aIout(k-1) + bU (k-1) (formula 2), wherein Iout(k) Is the measured value of the kth output current of the permanent magnet motor, U (k-1) is the measured value of the voltage value of the motor coil of the (k-1) th permanent magnet motor, a and b are correlation coefficients, and the measured values are taken intoThe values of the correlation coefficients a, b can be solved in equation 2.
The corresponding relation between the discrete model parameters of the permanent magnet motor and the motor parameters is as follows:
wherein, R is the equivalent resistance of the permanent magnet motor, L is the equivalent inductance of the permanent magnet motor, T is the sampling period of the discrete domain, the values of the relative systems a and b are substituted into the formula 3, and the equivalent resistance and the equivalent inductance of the permanent magnet motor can be calculated.
According to analysis, the smaller the period of the discrete domain is, the higher the similarity between the discrete model and the continuous model is, and the higher the identification precision of the motor parameters is.
The invention also provides a permanent magnet motor parameter identification device, which comprises:
an excitation amplitude identification module: the method is used for calculating the excitation voltage in the offline parameter identification process of the permanent magnet motor;
pressure drop compensation VfA calculation module: for calculating the actual voltage drop of the permanent magnet motor;
a parameter identification module: for calculating parameters of the permanent magnet machine.
In another embodiment, the voltage drop compensation VfThe calculation module comprises:
an excitation power supply control unit: the excitation voltage is used for applying an excitation voltage with a preset amplitude to the permanent magnet motor;
a current sampling unit: the device is used for measuring the working current of the permanent magnet motor;
an arithmetic unit: for calculating the pressure drop compensation V according to a predetermined modelf。
The permanent magnet motor parameter identification device can effectively identify the parameters of the permanent magnet motor, is beneficial to parameter adjustment of the permanent magnet motor, and is low in cost.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention. Furthermore, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.
Claims (8)
1. An offline parameter identification method for a permanent magnet motor is characterized by comprising the following steps:
determining an excitation amplitude U;
pressure drop compensation VfA determination step: the method comprises the following steps: locking the permanent magnet motor to an electrical angle zero position;
step voltage is applied to the permanent magnet motor, and the amplitude of the voltage is gradually increased until the value of the U-phase current reaches a first preset point current value Iu1And a second preset point current value Iu2Recording the corresponding first preset point voltage value Uα1And a second preset point voltage value Uα2；
Applying voltage to the permanent magnet motor, and recording the voltage value U when the voltage amplitude is a first preset pointα1And a second preset point voltage value Uα2Corresponding first current value I'u1And a second current value I'u2；
The first current value I'u1And the second current value I'u2The first preset point voltage value Uα1And said second preset point voltage value Uα2Substituting into formula
Calculating to obtain the voltage drop compensation V of the permanent magnet motorfAnd an armature resistance value R' of the permanent magnet motor;
and (3) parameter calculation: applying a voltage U (k) to the permanent magnet motor, wherein the amplitude of the voltage U (k) is equal to the excitation amplitude U within an error range, and recording the working current I (k) of the permanent magnet motor at the moment;
will correct voltage U'(k)Substituting the working current I (k) into a preset model, and correcting the voltage U'(k)Equal to U (k) -VfAnd k is a measurement serial number, and the offline parameters of the permanent magnet motor are calculated.
2. The method for identifying the offline parameters of the permanent magnet motor according to claim 1, wherein the excitation amplitude value U is determined by:
and applying voltage to the permanent magnet motor, and gradually increasing the amplitude of the voltage until the working current of the permanent magnet motor reaches the rated current value of 100%, wherein the amplitude of the voltage at the moment is the excitation amplitude U.
3. The method for identifying the offline parameters of the permanent magnet motor according to claim 1, wherein the first preset point current value I isu1Equal to 80% of the rated current value of the permanent magnet motor, and the second preset point current value Iu2Equal to 90% of the rated current value of the permanent magnet motor.
4. The permanent magnet motor offline parameter identification method according to claim 1, wherein the preset model comprises a recursive least square model or a least square model.
5. The permanent magnet motor offline parameter identification method according to claim 4, wherein a recursion formula of the recursion least square method model is Iout(k)＝-aIout(k-1) + bU (k-1), wherein Iout(k) And the measured value is the kth output current of the permanent magnet motor, U (k-1) is the measured value of the (k-1) th motor coil voltage of the permanent magnet motor, and a and b are correlation coefficients.
6. The method as claimed in claim 5, wherein the parameters of the permanent magnet motor include equivalent resistance R and equivalent inductance L, and
t is the sampling period of the discrete domain.
7. A permanent magnet motor parameter identification device, characterized by comprising:
an excitation amplitude identification module: the excitation voltage is used for calculating the excitation voltage in the offline parameter identification process of the permanent magnet motor;
pressure drop compensation VfA calculation module: for calculating an actual voltage drop of the permanent magnet motor;
a parameter identification module: for calculating parameters of the permanent magnet machine.
8. The pm machine parameter identification apparatus as claimed in claim 7, wherein said voltage drop compensation VfThe calculation module comprises:
an excitation power supply control unit: the excitation voltage is used for applying a preset amplitude value to the permanent magnet motor;
a current sampling unit: the device is used for measuring the working current of the permanent magnet motor;
an arithmetic unit: for calculating the pressure drop compensation V according to a predetermined modelf。
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| CN112100569A (en) * | 2020-08-24 | 2020-12-18 | 瑞声新能源发展(常州)有限公司科教城分公司 | Motor parameter tracking method, device, equipment and medium based on frequency domain analysis |
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| CN111781497A (en) * | 2020-06-11 | 2020-10-16 | 宁波奥克斯电气股份有限公司 | Method and device for identifying compressor model, maintenance equipment and air conditioner |
| CN112100569A (en) * | 2020-08-24 | 2020-12-18 | 瑞声新能源发展(常州)有限公司科教城分公司 | Motor parameter tracking method, device, equipment and medium based on frequency domain analysis |
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