CN115102455A - Method and device for positioning initial position of permanent magnet synchronous motor rotor for pump - Google Patents
Method and device for positioning initial position of permanent magnet synchronous motor rotor for pump Download PDFInfo
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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
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/24—Vector control not involving the use of rotor position or rotor speed sensors
- H02P21/32—Determining the initial rotor position
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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
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/13—Observer control, e.g. using Luenberger observers or Kalman filters
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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
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/14—Electronic commutators
- H02P6/16—Circuit arrangements for detecting position
- H02P6/18—Circuit arrangements for detecting position without separate position detecting elements
- H02P6/183—Circuit arrangements for detecting position without separate position detecting elements using an injected high frequency signal
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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
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Abstract
The invention discloses a method and a device for positioning the initial position of a permanent magnet synchronous motor rotor for a pump, wherein the method comprises the steps of acquiring a high-frequency current signal of a permanent magnet synchronous motor under the injection of a high-frequency voltage signal; performing first signal processing on the high-frequency current signal to obtain a first high-frequency current signal; and inputting the rotor position observation error into a pre-constructed rotor position state observer to obtain a rotor position initial observation value, keeping continuous injection of a high-frequency signal, and performing difference and accumulation operation on the high-frequency current by combining the saturation nonlinear characteristic of the permanent magnet synchronous motor stator. Judging whether the deviation value between the initial information of the rotor position and the actual position of the rotor is 180 degrees or not through the positive and negative of the accumulated value, then compensating the deviation value, completing the identification of the N-S magnetic poles of the rotor, and completing the positioning of the initial position of the rotor; the method can effectively realize the initial position positioning of the rotor of the permanent magnet synchronous motor under the condition of not increasing additional mechanical sensors.
Description
Technical Field
The invention relates to a method and a device for positioning an initial position of a permanent magnet synchronous motor rotor for a pump, and belongs to the technical field of drive control of pump load motors such as water pumps, oil pumps and air pumps.
Background
Compared with an induction motor which is applied in the field of pump loads in a large scale, the permanent magnet synchronous motor has the remarkable advantages of high efficiency, high power density, good speed regulation performance and the like. The application of permanent magnet synchronous motors to water pumps and oil pumps is becoming an industry trend owing to increasingly strict government requirements on energy conservation and emission reduction. The engineering mechanical vehicle comprises a hydraulic oil pump, a brake air pump, a steering power-assisted pump and a water pump with an emergency rescue drainage function, and the application of the permanent magnet synchronous motor has important significance for improving the performance levels of the engineering mechanical vehicle such as the operation time, the working efficiency and the like.
The traditional induction motor has the advantage of simpler starting method due to the inherent structure, and the problem of starting failure caused by step loss does not exist. For the synchronous motor, the inverter driving device leads current vectors with controllable sizes and directions to a stator winding of the permanent magnet synchronous motor through a three-phase wire harness, a stator winding coil can generate a stator magnetic field, if the relative angle between the stator magnetic field and a rotor permanent magnet magnetic field is reasonable, the stator magnetic field and the rotor permanent magnet magnetic field can interact to generate electromagnetic torque, mechanical torque is output outwards after friction torque is overcome, and therefore starting of the motor is achieved.
Aiming at the starting problem of a permanent magnet synchronous motor in pump occasions, the current advanced scheme is that test voltage signals such as sine waves and square waves are injected into a stator winding through an inverter driving device before starting, and the position of a rotor is analyzed by sampling stator exciting current and combining the characteristics of a motor body. After formal starting, a current vector generated by the inverter driving device is combined with an operation instruction to pull the rotor to operate by taking the current rotor position as an initial direction, and the scheme has good performance but high requirement on current sampling precision.
Aiming at the problem of high-reliability rotor positioning of a permanent magnet synchronous motor in a pump occasion, the prior technical scheme is that a main control chip generates symmetrical high-frequency square wave voltage signals with equal positive and negative amplitudes and 50% duty ratio respectively by software, the signals generate switching signals of power devices in a three-phase inverter bridge through an SVPWM (space vector pulse width modulation) strategy, and the high-frequency square wave voltage is applied to a three-phase stator winding of the motor through a three-phase wiring harness. The high-frequency square wave voltage can excite high-frequency response current at the stator of the motor, and the characteristics of the high-frequency response current are different due to the difference of the current rotor position of the motor. The main control chip obtains a high-frequency response current sampling value through sampling of the current sensor, then preliminarily judges the position of the rotor through the phase of the high-frequency response current, judges the N-S polarity of the magnetic pole of the rotor through the positive and negative symmetry of the high-frequency response current, and combines the two to obtain the current position of the rotor.
Because the current sensor and the signal processing circuit thereof comprise analog devices, the temperature drift phenomenon exists. The change of the environmental temperature can cause the deviation error between the collected current information and the real current information. The low-precision current sensor with lower cost has poorer inhibition and compensation capabilities on sampling errors caused by the temperature drift phenomenon. In the prior art, at the stage of judging the N-S polarity of the rotor magnetic pole, the offset error in the current sampling value may cause misjudgment on the positive and negative symmetry of the main control chip to the high-frequency response current, which leads to a wrong judgment on the polarity of the rotor magnetic pole, and then causes a positioning failure of the initial position of the rotor, and finally leads to a failed start-up.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a method and a device for positioning the initial position of a rotor of a permanent magnet synchronous motor for a pump, which can effectively realize the positioning of the initial position of the rotor of the permanent magnet synchronous motor under the condition of not adding an additional mechanical sensor.
In order to achieve the purpose, the invention is realized by adopting the following technical scheme:
in a first aspect, the present invention provides a method for positioning an initial position of a rotor of a permanent magnet synchronous motor for a pump, including:
acquiring a high-frequency current signal of the permanent magnet synchronous motor under the injection of a high-frequency voltage signal;
performing first signal processing on the high-frequency current signal to obtain a first high-frequency current signal;
carrying out low-pass filtering, difference operation and per-unit processing on the first high-frequency current signal to obtain a rotor position observation error;
inputting the rotor position observation error into a pre-constructed rotor position state observer to obtain a rotor position preliminary observation value;
performing second signal processing on the high-frequency current signal to obtain a second high-frequency current signal;
in each injection period, carrying out numerical operation on the plurality of second high-frequency current signals to obtain a single-period saturation current difference value;
continuously executing a plurality of injection cycles to obtain a plurality of single-cycle saturation current difference values, and performing accumulation operation on the single-cycle saturation current difference values to obtain a saturation current difference value multi-cycle accumulated value;
obtaining the polarity of the N-S magnetic pole of the rotor and a polarity judgment compensation value by judging the positive and negative of the multi-period accumulated value of the saturation current difference value;
and adding the rotor position initial observed value and the polarity judgment compensation value to obtain a rotor position observed value, and finishing positioning the rotor position of the permanent magnet synchronous motor.
Further, the acquiring a high-frequency current signal of the permanent magnet synchronous motor under the injection of the high-frequency voltage signal includes:
observing shafting rotating to motor
Shaft injection high frequency trapezoidal wave voltage signal:
wherein, U inj For the amplitude of the injection voltage signal, T inj The injection period of the high-frequency signal is shown, and n is the period number of the injection signal;
defining theta in permanent magnet synchronous machines e Is the true rotor pole angle;
for observing rotorsMagnetic pole angle;
the error angle of the rotor magnetic pole observation is satisfied
Injecting a high frequency voltage into
In a coordinate system, i.e.
Wherein,
respectively observing a direct axis d axis and a quadrature axis q axis of the permanent magnet synchronous motor to obtain high-frequency voltage signals injected;
d-q coordinate system and
the voltages in the coordinate system satisfy the following relations:
wherein
Wherein u is dh 、u qh The high-frequency voltage signals are respectively injected under a real direct-axis d-axis coordinate system and a real quadrature-axis q-axis coordinate system of the permanent magnet synchronous motor, and T () is a coordinate transformation matrix;
the permanent magnet synchronous motor obtains a high-frequency current signal under the action of a high-frequency voltage excitation signal, and the requirements are as follows:
where p is a differential operator, i dh 、i qh Respectively high-frequency current signals under a d-q coordinate system of the permanent magnet synchronous motor; l is d 、L q Inductance parameters under a d-q coordinate system of the permanent magnet synchronous motor are respectively.
Further, performing a first signal processing on the high-frequency current signal to obtain a first high-frequency current signal, includes:
performing coordinate conversion on the high-frequency current signal, d m -q m The currents in the coordinate system and the d-q coordinate system satisfy the following relation:
wherein,
are respectively d m -q m A high-frequency current signal under a coordinate system;
d m -q m including rotor magnetic pole observation error angle under coordinate system
The high-frequency current signal of (a) is:
wherein L is 0 、L 1 Respectively average inductance parameters of the permanent magnet synchronous motor: l is 0 ＝(L d +L q )/2,L 0 ＝(L d -L q )/2；
And then, carrying out absolute value taking processing on the high-frequency current signal after the coordinate conversion to obtain a first high-frequency current signal.
Further, after the low-pass filtering, the difference operation and the per unit processing are performed on the first high-frequency current signal, obtaining a rotor position observation error, including:
and performing low-pass filtering processing on the first high-frequency current signal by using a first-order low-pass filter to extract a high-frequency current peak value, wherein the formula is as follows:
wherein k is a coefficient generated in the integration process;
and carrying out difference operation on the high-frequency current peak value to extract a position error signal, wherein the formula is as follows:
performing per-unit processing on the position error signal to obtain a rotor position observation error, wherein the specific process is as follows:
and calculating the square sum of the high-frequency current peak value, wherein the formula is as follows:
when the observation position is close to the true value, the following conditions are satisfied:
the rotor position observation error is expressed as:
further, inputting the rotor position observation error into a rotor position state observer which is constructed in advance to obtain a rotor position preliminary observation value, including:
after the observation error epsilon of the rotor position is obtained, the baseSelecting rotor electrical angular velocity omega from a permanent magnet synchronous motor motion equation e Rotor electrical position θ e Is a state variable; selecting rotor electrical position θ e Is an output variable; considering only the difference between the electromagnetic torque and the load torque in the steady state as the system input, and the input is zero, without considering the changes of the electromagnetic torque and the load torque:
constructed at theta e And omega e Equation of state for state variables:
where x is the system state vector, and x is [ theta ═ theta [ [ theta ] e ω e ] T (ii) a u is the system input, where the input is assumed to be 0; y is system input, and y is equal to theta e (ii) a A is a system matrix and is a system matrix,
b is a system input matrix, and B is a system input matrix,
c is the system output matrix, C ═ 10]；
Constructing a rotor position state observer:
wherein,
is a feedback matrix of the observer;
observed value of rotor position
And a rotorPosition actual value theta e Has a transfer function of
Wherein s is a Laplace operator in the control system and can be obtained by a transfer function denominator, and the system is a second-order system;
the second-order system is designed to have damping coefficient zeta as the optimal damping coefficient commonly used in engineering
Rho is the undamped oscillation frequency of a second-order system, and the control parameters of the state observer are designed to be
The state observer preliminarily observes the rotor position after a plurality of injection periods
Converging to the true rotor position.
Further, performing a second signal processing on the high-frequency current signal to obtain a second high-frequency current signal includes:
maintaining continuous injection of high frequency trapezoidal wave voltage signal in
Current sampling is carried out at any moment and three-phase current sampling values are converted to
Coordinate system of obtaining
In that
Current sampling is carried out at any moment and three-phase current sampling values are converted to be three-phase current sampling values through coordinate conversion
Coordinate system of obtaining
In that
Current sampling is carried out at any moment and three-phase current sampling values are converted to
Coordinate system of obtaining
At T ═ n +1) T inj Current sampling is carried out at any moment and three-phase current sampling values are converted to
Coordinate system of obtaining
Further, the method for obtaining the polarity of the N-S magnetic pole and the polarity determination compensation value of the rotor by determining the positive and negative of the multi-cycle accumulated value of the saturation current difference value includes:
judging the positive and negative of the multi-period accumulated value, if the accumulated value is greater than zero, judging that the observed position converges to the N pole of the rotor magnetic pole, and judging the compensation value theta by the polarity cmp Is zero; if the measured value is less than zero, the observed position is judged to be converged to the S pole of the rotor magnetic pole, and the polarity judgment compensation value theta cmp Is 180 deg..
In a second aspect, the present invention provides a positioning device for an initial position of a rotor of a permanent magnet synchronous motor for a pump, including:
the high-frequency current signal is used for acquiring a high-frequency current signal of the permanent magnet synchronous motor under the injection of the high-frequency voltage signal;
the signal processing unit is used for carrying out first-time signal processing on the high-frequency current signal to obtain a first high-frequency current signal;
a rotor position observation error obtaining unit, configured to obtain a rotor position observation error after performing low-pass filtering, difference operation, and per-unit processing on the first high-frequency current signal;
the rotor position preliminary observation value acquisition unit is used for inputting the rotor position observation error into a rotor position state observer which is constructed in advance to obtain a rotor position preliminary observation value;
a second high-frequency current signal obtaining unit, configured to perform second signal processing on the high-frequency current signal to obtain a second high-frequency current signal;
the numerical operation unit is used for carrying out numerical operation on the plurality of second high-frequency current signals in each injection period to obtain a single-period saturation current difference value;
the accumulation operation unit is used for continuously executing a plurality of injection periods to obtain a plurality of single-period saturation current difference values, and performing accumulation operation on the single-period saturation current difference values to obtain a saturation current difference value multi-period accumulated value;
the judging unit is used for obtaining the polarity of the N-S magnetic pole of the rotor and a polarity judgment compensation value by judging the positive and negative of the multi-period accumulated value of the saturation current difference value;
and the position positioning unit is used for adding the initial rotor position observation value and the polarity judgment compensation value to obtain a rotor position observation value and finish positioning the rotor position of the permanent magnet synchronous motor.
In a third aspect, the invention provides a device for positioning an initial position of a rotor of a permanent magnet synchronous motor for a pump, which comprises a processor and a storage medium;
the storage medium is to store instructions;
the processor is configured to operate in accordance with the instructions to perform the steps of the method according to any one of the preceding claims.
In a fourth aspect, the invention provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the method of any one of the preceding claims.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a method and a device for positioning the initial position of a permanent magnet synchronous motor rotor for a pump, which can realize the positioning of the rotor position of the permanent magnet synchronous motor under the condition of using a low-precision current sensor without using a mechanical position sensor and a high-precision current sensor and provide the initial position information of the rotor for the execution and the starting of a motor. Compared with the traditional pulse signal injection and square wave signal injection, the step wave signal injection adopted by the invention can eliminate the interference of the current sampling offset error on the saturation current difference value on the rotor N-S polarity identification by utilizing the iron core saturation characteristic, thereby greatly improving the accuracy of the N-S polarity identification; the method can be applied to pump load occasions without mechanical position sensors and low-precision current sensors, and can realize the positioning of the initial position of the rotor of the permanent magnet synchronous motor.
Drawings
FIG. 1 is a schematic diagram of a coordinate system of a motor provided by an embodiment of the present invention;
fig. 2 is an overall block diagram of a method for positioning an initial position of a rotor of a permanent magnet synchronous motor for a pump according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a processing flow of a position error signal extraction current signal according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a signal processing flow of the position observer according to the embodiment of the present invention.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
Example 1
The embodiment introduces a method for positioning an initial position of a rotor of a permanent magnet synchronous motor for a pump, which includes:
acquiring a high-frequency current signal of the permanent magnet synchronous motor under the injection of a high-frequency voltage signal;
performing first signal processing on the high-frequency current signal to obtain a first high-frequency current signal;
carrying out low-pass filtering, difference operation and per-unit processing on the first high-frequency current signal to obtain a rotor position observation error;
inputting the rotor position observation error into a pre-constructed rotor position state observer to obtain a rotor position preliminary observation value;
performing second signal processing on the high-frequency current signal to obtain a second high-frequency current signal;
in each injection period, carrying out numerical operation on the plurality of second high-frequency current signals to obtain a single-period saturation current difference value;
continuously executing a plurality of injection cycles to obtain a plurality of single-cycle saturation current difference values, and performing accumulation operation on the single-cycle saturation current difference values to obtain a saturation current difference value multi-cycle accumulated value;
obtaining the polarity of the N-S magnetic pole of the rotor and a polarity judgment compensation value by judging the positive and negative of the multi-period accumulated value of the saturation current difference value;
and adding the rotor position initial observed value and the polarity judgment compensation value to obtain a rotor position observed value, and finishing positioning the rotor position of the permanent magnet synchronous motor.
As shown in fig. 1 to 4, fig. 1 is a schematic diagram of a coordinate system of a motor related to the present invention, which includes a stationary axis system, a d-q axis system,
axis system (observation axis system) and d m -q m The phase relation of the shafting (measuring shafting). Wherein the measurement axis lags behind the observation axis by 45 deg., wherein theta e Is the true rotor pole angle;
for observing the angle of the magnetic pole of the rotor;
the error angle of the rotor magnetic pole observation is satisfied
FIG. 2 is an overall block diagram of the present invention; in the figure, the position of the first and second end faces,
the voltage command value under the observation shafting is obtained;
the current value is a static shafting lower voltage instruction value, iA and iB are motor current sampling values, and i alpha and i beta are static shafting lower current values; epsilon is the extracted position observation error,
for preliminary observations of rotor position, θ cmp The compensation value is judged for polarity.
Fig. 3 is a flow of processing the position error signal extraction current signal. Wherein iA and iB are motor current sampling values, and i alpha and i beta are lower current values of a static shaft system;
for observing the current value under the axis, | · | is an absolute value operation indication, LPF is a low pass filter,
the method is divided into two steps of observing the current peak value under the axis system and dividing.
Fig. 4 shows a signal processing flow of the position observer, where kp is a proportional operation coefficient and ki is an integral operation coefficient.
The embodiment provides a method for positioning an initial position of a permanent magnet synchronous motor rotor for a pump, which specifically relates to the following steps in an application process:
the method comprises the following steps: before the permanent magnet synchronous motor is started, a high-frequency step wave voltage detection signal is generated by a main control chip and is injected into a motor rotation observation shafting
A shaft; high frequency under rotating observation coordinate system based on permanent magnet synchronous motorThe mathematical model carries out a series of signal processing such as coordinate transformation, absolute value taking, low-pass filtering, per-unit processing, observer tracking position and the like on a high-frequency current sampling value to obtain rotor position preliminary information;
step two: and keeping the continuous injection of the high-frequency signal, and performing difference and accumulation operation on the high-frequency current by combining the saturation nonlinear characteristic of the permanent magnet synchronous motor stator. Whether the deviation value between the initial information of the rotor position and the actual position of the rotor is 180 degrees is judged through the positive and negative of the accumulated value, and then the rotor position is compensated, so that the N-S magnetic poles of the rotor are identified, and the initial position of the rotor is positioned.
Further, before the permanent magnet synchronous motor is started, the first step generates a high-frequency step wave voltage detection signal through a main control chip and performs signal processing on a high-frequency current sampling value to obtain the preliminary rotor position information, specifically:
observing shaft system rotating to motor
Shaft injection high frequency trapezoidal wave voltage signal:
wherein U is inj For the amplitude of the injection voltage signal, T inj N is the number of cycles of the injection signal.
Defining theta in permanent magnet synchronous machines e Is the true rotor pole angle;
for observing the angle of the magnetic pole of the rotor;
the error angle of the rotor magnetic pole observation is satisfied
Injecting a high frequency voltage into
In a coordinate system, i.e.
Wherein,
respectively observing a direct axis d axis and a quadrature axis q axis of the permanent magnet synchronous motor to obtain high-frequency voltage signals injected;
d-q coordinate system and
the voltages in the coordinate system satisfy the following relationship
Wherein
Wherein u is dh 、u qh The high-frequency voltage signals are respectively injected into a permanent magnet synchronous motor under a real direct-axis d-axis coordinate system and a real quadrature-axis q-axis coordinate system, and T () is a coordinate transformation matrix;
moreover, the high-frequency current response signal of the permanent magnet synchronous motor under the action of the high-frequency voltage excitation signal meets the requirements
Where p is the differential operator, i dh 、i qh Respectively high-frequency current signals under a d-q coordinate system of the permanent magnet synchronous motor; l is d 、L q Inductance parameters under a d-q coordinate system of the permanent magnet synchronous motor are respectively set;
likewise, d m -q m The current in the coordinate system and the d-q coordinate system satisfies the following relation
Wherein,
are respectively d m -q m A high-frequency current signal under a coordinate system;
d m -q m including rotor magnetic pole observation error angle under coordinate system
The high-frequency current signal of (a) is:
wherein L is 0 、L 1 Respectively mean inductance parameters of the permanent magnet synchronous motor: l is 0 ＝(L d +L q )/2,L 0 ＝(L d -L q )/2；
Then, absolute value processing is carried out on the high-frequency current;
the next step is to use a first-order low-pass filter to carry out low-pass filtering processing on the signal and extract a high-frequency current peak value
Wherein k is a coefficient generated in the integration process;
performing a difference operation to extract a position error signal
Further, the voltage amplitude and the period of the injection voltage are subjected to per unit processing so as to improve the robustness of the injection voltage amplitude and the period.
The sum of the squares of the high frequency current peaks is
When the observed position is close to the true value, the condition is satisfied
The position error can be expressed as
After the position observation error epsilon is obtained, based on the motion equation of the permanent magnet synchronous motor, the rotor electrical angular velocity omega is selected e Rotor electrical position θ e Is a state variable; selecting rotor electrical position θ e Is an output variable; the variation of the electromagnetic torque and the load torque is not considered, that is, only the difference between the electromagnetic torque and the load torque in the steady state is considered as the system input, and the input is zero:
constructed at theta e And ω e Equation of state as a state variable
Where x is the system state vector, and x is [ theta ═ theta [ [ theta ] e ω e ] T (ii) a u is the system input, which is assumed to be 0; y is the system input, and y is θ e (ii) a A is a system matrix and is a system matrix,
b is a system input matrix, and B is a system input matrix,
c is the system output matrix, C ═ 10]。
Constructing a rotor position state observer:
wherein,
is the feedback matrix of the observer.
Observed value of rotor position
With actual value of rotor position theta e Has a transfer function of
Wherein s is a Laplace operator in the control system and can be obtained by a transfer function denominator, and the system is a second-order system;
in order to balance the system between better stability and faster response speed, the second-order system is designed to have a damping coefficient zeta which is the optimal damping coefficient commonly used in engineering
ρ is the undamped oscillation frequency of the second order system. The control parameters of the state observer are designed as
The state observer initially positions the rotor after a number of injection cyclesStep observation value
Converge to the true rotor position but cannot distinguish between N-S polarities.
Step two, keeping continuous injection of the high-frequency trapezoidal wave voltage signal in the step (1)
Current sampling is carried out at any moment and three-phase current sampling values are converted to be three-phase current sampling values through coordinate conversion
Coordinate system of obtaining
In that
Current sampling is carried out at any moment and three-phase current sampling values are converted to
Coordinate system of obtaining
In that
Current sampling is carried out at any moment and three-phase current sampling values are converted to
Coordinate system of obtaining
At T ═ n +1) T inj Current sampling is carried out at any moment and three-phase current sampling values are converted to be three-phase current sampling values through coordinate conversion
A coordinate system of the coordinate system,to obtain
Further, carrying out numerical operation on the four current sampling values in each injection period to obtain a single-period saturation current difference I k ：
Performing a plurality of injection cycles in succession to obtain I 1 、I 2 、I 3 ……I k (ii) a Will I 1 、I 2 、I 3 ……I k And accumulating to obtain a multi-period accumulated value sigma I of the saturation current difference value.
Further, the positive and negative of the multi-period accumulated value sigma I are judged, if the accumulated value is larger than zero, the observation position is converged to the N pole of the rotor magnetic pole in the judgment step, and the polarity judgment compensation value theta is cmp Is zero; if the magnetic flux is less than zero, judging that the observation position of the step one is converged to the S pole of the rotor magnetic pole, and judging the compensation value theta by the polarity cmp Is 180 deg..
Finally, the rotor position is preliminarily observed
And a polarity determination compensation value theta cmp Adding to obtain rotor position observed value
And finishing positioning the rotor of the permanent magnet synchronous motor.
The technical scheme of the invention brings beneficial effects
The method of the invention does not need to use a mechanical position sensor and a high-precision current sensor, can realize the positioning of the rotor position of the permanent magnet synchronous motor under the condition of using a low-precision current sensor, and provides the initial position information of the rotor for the motor to execute the starting. Compared with the traditional pulse signal injection and square wave signal injection, the step wave signal injection adopted by the invention can eliminate the interference of the current sampling offset error on the saturation current difference value on the rotor N-S polarity identification by utilizing the iron core saturation characteristic, thereby greatly improving the accuracy of the N-S polarity identification; the method can be applied to pump load occasions without mechanical position sensors and low-precision current sensors, and can realize the positioning of the initial position of the rotor of the permanent magnet synchronous motor.
Example 2
The embodiment provides a PMSM rotor initial position positioner for pump, includes:
the high-frequency current signal is used for acquiring a high-frequency current signal of the permanent magnet synchronous motor under the injection of the high-frequency voltage signal;
the signal processing unit is used for carrying out first-time signal processing on the high-frequency current signal to obtain a first high-frequency current signal;
a rotor position observation error obtaining unit, configured to obtain a rotor position observation error after performing low-pass filtering, difference operation, and per-unit processing on the first high-frequency current signal;
the rotor position preliminary observation value acquisition unit is used for inputting the rotor position observation error into a rotor position state observer which is constructed in advance to obtain a rotor position preliminary observation value;
a second high-frequency current signal obtaining unit, configured to perform second signal processing on the high-frequency current signal to obtain a second high-frequency current signal;
the numerical operation unit is used for carrying out numerical operation on the plurality of second high-frequency current signals in each injection period to obtain a single-period saturation current difference value;
the accumulation operation unit is used for continuously executing a plurality of injection periods to obtain a plurality of single-period saturation current difference values, and performing accumulation operation on the single-period saturation current difference values to obtain a saturation current difference value multi-period accumulated value;
the judging unit is used for obtaining the polarity of the N-S magnetic pole of the rotor and a polarity judging compensation value by judging the positive and negative of the multi-period accumulated value of the saturation current difference value;
and the position positioning unit is used for adding the initial rotor position observation value and the polarity judgment compensation value to obtain a rotor position observation value and finish positioning the rotor position of the permanent magnet synchronous motor.
Example 3
The embodiment provides a device for positioning an initial position of a rotor of a permanent magnet synchronous motor for a pump, which comprises a processor and a storage medium;
the storage medium is to store instructions;
the processor is configured to operate in accordance with the instructions to perform the steps of the method according to any of embodiment 1.
Example 4
The present embodiment provides a computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the steps of the method of any one of the embodiment 1.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The method for positioning the initial position of the rotor of the permanent magnet synchronous motor for the pump is characterized by comprising the following steps of:
acquiring a high-frequency current signal of the permanent magnet synchronous motor under the injection of a high-frequency voltage signal;
performing first signal processing on the high-frequency current signal to obtain a first high-frequency current signal;
carrying out low-pass filtering, difference operation and per-unit processing on the first high-frequency current signal to obtain a rotor position observation error;
inputting the rotor position observation error into a pre-constructed rotor position state observer to obtain a rotor position preliminary observation value;
performing second signal processing on the high-frequency current signal to obtain a second high-frequency current signal;
in each injection period, carrying out numerical operation on the plurality of second high-frequency current signals to obtain a single-period saturation current difference value;
continuously executing a plurality of injection periods to obtain a plurality of single-period saturation current difference values, and performing accumulation operation on the single-period saturation current difference values to obtain a saturation current difference value multi-period accumulated value;
obtaining the polarity of the N-S magnetic pole of the rotor and a polarity judgment compensation value by judging the positive and negative of the multi-period accumulated value of the saturation current difference value;
and adding the rotor position initial observed value and the polarity judgment compensation value to obtain a rotor position observed value, and finishing positioning the rotor position of the permanent magnet synchronous motor.
2. The method for positioning the initial position of the rotor of the permanent magnet synchronous motor for the pump according to claim 1, wherein the obtaining of the high-frequency current signal of the permanent magnet synchronous motor under the injection of the high-frequency voltage signal comprises:
observing shafting rotating to motor
Shaft injection high frequency trapezoidal wave voltage signal:
wherein, U inj For the amplitude of the injection voltage signal, T inj Is the injection period of the high-frequency signal, and n is the period number of the injection signal;
defining theta in a permanent magnet synchronous machine e Is the true rotor pole angle;
for observing the angle of the magnetic pole of the rotor;
the error angle of the rotor magnetic pole observation is satisfied
Injecting a high frequency voltage into
In a coordinate system, i.e.
Wherein,
respectively observing a direct axis d axis and a quadrature axis q axis of the permanent magnet synchronous motor to obtain high-frequency voltage signals injected;
d-q coordinate system and
the voltages in the coordinate system satisfy the following relations:
wherein
Wherein u is dh 、u qh The high-frequency voltage signals are respectively injected into a permanent magnet synchronous motor under a real direct-axis d-axis coordinate system and a real quadrature-axis q-axis coordinate system, and T () is a coordinate transformation matrix;
the permanent magnet synchronous motor obtains a high-frequency current signal under the action of a high-frequency voltage excitation signal, and the requirements are as follows:
where p is a differential operator, i dh 、i qh Respectively high-frequency current signals under a d-q coordinate system of the permanent magnet synchronous motor; l is a radical of an alcohol d 、L q Inductance parameters under a d-q coordinate system of the permanent magnet synchronous motor are respectively.
3. The method for positioning the initial position of the rotor of the permanent magnet synchronous motor for the pump according to claim 2, wherein the step of performing a first signal processing on the high-frequency current signal to obtain a first high-frequency current signal comprises:
performing coordinate conversion on the high-frequency current signal, d m -q m The currents in the coordinate system and the d-q coordinate system satisfy the following relations:
wherein,
are respectively d m -q m A high-frequency current signal under a coordinate system;
d m -q m including rotor magnetic pole observation error angle under coordinate system
The high-frequency current signal of (a) is:
wherein L is 0 、L 1 Respectively average inductance parameters of the permanent magnet synchronous motor: l is 0 ＝(L d +L q )/2,L 0 ＝(L d -L q )/2；
And then, carrying out absolute value taking processing on the high-frequency current signal after the coordinate conversion to obtain a first high-frequency current signal.
4. The method for positioning the initial position of the rotor of the permanent magnet synchronous motor for the pump according to claim 3, wherein obtaining the observation error of the position of the rotor after performing low-pass filtering, difference operation and per unit processing on the first high-frequency current signal comprises:
and performing low-pass filtering processing on the first high-frequency current signal by using a first-order low-pass filter to extract a high-frequency current peak value, wherein the formula is as follows:
wherein k is a coefficient generated in the integration process;
and carrying out difference operation on the high-frequency current peak value to extract a position error signal, wherein the formula is as follows:
performing per-unit processing on the position error signal to obtain a rotor position observation error, wherein the specific process is as follows:
and calculating the square sum of the high-frequency current peak value, wherein the formula is as follows:
when the observation position is close to the true value, the following conditions are satisfied:
the rotor position observation error is expressed as:
5. the method for positioning the initial position of the rotor of the permanent magnet synchronous motor for the pump according to claim 4, wherein the step of inputting the observation error of the rotor position into a pre-constructed rotor position state observer to obtain a preliminary observation value of the rotor position comprises the following steps:
after the observation error epsilon of the rotor position is obtained, the rotor electrical angular velocity omega is selected based on the motion equation of the permanent magnet synchronous motor e Rotor electrical position θ e Is a state variable; selecting rotor electrical position θ e Is an output variable; considering only the difference between the electromagnetic torque and the load torque in the steady state as the system input, and the input is zero, without considering the changes of the electromagnetic torque and the load torque:
constructed at theta e And ω e Equation of state for state variables:
where x is the system state vector, and x is [ θ ═ θ [ ] e ω e ] T (ii) a u is the system input, which is assumed to be 0; y is system input, and y is equal to theta e (ii) a A is a system matrix and is a system matrix,
b is a system input matrix, and B is a system input matrix,
c is the system output matrix, C ═ 10]；
Constructing a rotor position state observer:
wherein,
is a feedback matrix of the observer;
observed value of rotor position
With actual value of rotor position theta e Has a transfer function of
Wherein s is a Laplace operator in the control system and can be obtained by a transfer function denominator, and the system is a second-order system;
the second-order system is designed to have damping coefficient zeta as the optimal damping coefficient commonly used in engineering
Rho is the undamped oscillation frequency of a second-order system, and the control parameters of the state observer are designed as
The state observer obtains a preliminary rotor position observation value after a plurality of injection periods
Converging to the true rotor position.
6. The method for positioning the initial position of the rotor of the permanent magnet synchronous motor for the pump according to claim 5, wherein the performing the second signal processing on the high-frequency current signal to obtain a second high-frequency current signal comprises:
continuous injection for maintaining high frequency trapezoidal wave voltage signalIn a
Current sampling is carried out at any moment and three-phase current sampling values are converted to
Coordinate system of obtaining
In that
Current sampling is carried out at any moment and three-phase current sampling values are converted to be three-phase current sampling values through coordinate conversion
Coordinate system of obtaining
In that
Current sampling is carried out at any moment and three-phase current sampling values are converted to
Coordinate system of obtaining
At T ═ n +1) T inj Current sampling is carried out at any moment and three-phase current sampling values are converted to
Coordinate system of obtaining
7. The method for positioning the initial position of the rotor of the permanent magnet synchronous motor for the pump according to claim 6, wherein the obtaining of the polarity of the N-S magnetic pole and the polarity judgment compensation value of the rotor by judging the positive and negative of the multi-cycle accumulated value of the saturation current difference comprises:
judging the positive and negative of the multi-period accumulated value, if the accumulated value is greater than zero, judging that the observed position converges to the N pole of the rotor magnetic pole, and judging the compensation value theta by the polarity cmp Is zero; if the measured value is less than zero, the observed position is judged to be converged to the S pole of the rotor magnetic pole, and the polarity judgment compensation value theta cmp Is 180 deg..
8. The utility model provides a PMSM rotor initial position positioner for pump which characterized in that includes:
the high-frequency current signal is used for acquiring a high-frequency current signal of the permanent magnet synchronous motor under the injection of the high-frequency voltage signal;
the signal processing unit is used for carrying out first-time signal processing on the high-frequency current signal to obtain a first high-frequency current signal;
a rotor position observation error obtaining unit, configured to perform low-pass filtering, difference operation, and per-unit processing on the first high-frequency current signal, and obtain a rotor position observation error;
the rotor position preliminary observation value acquisition unit is used for inputting the rotor position observation error into a rotor position state observer which is constructed in advance to obtain a rotor position preliminary observation value;
a second high-frequency current signal obtaining unit, configured to perform second signal processing on the high-frequency current signal to obtain a second high-frequency current signal;
the numerical operation unit is used for carrying out numerical operation on the plurality of second high-frequency current signals in each injection period to obtain a single-period saturation current difference value;
the accumulation operation unit is used for continuously executing a plurality of injection periods to obtain a plurality of single-period saturation current difference values, and performing accumulation operation on the single-period saturation current difference values to obtain a saturation current difference value multi-period accumulated value;
the judging unit is used for obtaining the polarity of the N-S magnetic pole of the rotor and a polarity judgment compensation value by judging the positive and negative of the multi-period accumulated value of the saturation current difference value;
and the position positioning unit is used for adding the preliminary rotor position observation value and the polarity judgment compensation value to obtain a rotor position observation value and finishing positioning the rotor position of the permanent magnet synchronous motor.
9. The utility model provides a PMSM rotor initial position positioner for pump which characterized in that: comprising a processor and a storage medium;
the storage medium is used for storing instructions;
the processor is configured to operate in accordance with the instructions to perform the steps of the method according to any one of claims 1 to 7.
10. A computer-readable storage medium having stored thereon a computer program, characterized in that: the program when executed by a processor implements the steps of the method of any one of claims 1 to 7.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2024132022A1 (en) * | 2022-12-19 | 2024-06-27 | Schaeffler Technologies AG & Co. KG | Method for recording an initial rotational position of a rotor |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2024132022A1 (en) * | 2022-12-19 | 2024-06-27 | Schaeffler Technologies AG & Co. KG | Method for recording an initial rotational position of a rotor |
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