JP5798513B2 - Method and apparatus for detecting initial magnetic pole position of permanent magnet synchronous motor, and control apparatus for permanent magnet synchronous motor - Google Patents

Description

  The present invention relates to a method and apparatus for detecting an initial magnetic pole position of a permanent magnet synchronous motor, and a control apparatus for a permanent magnet synchronous motor. In particular, the present invention relates to a method for detecting a magnetic pole position when a rotor of a permanent magnet synchronous motor is stopped without using a position sensor for detecting a magnetic pole position.

  In recent years, synchronous motors using permanent magnets (permanent magnet synchronous motors, PMSM, hereinafter referred to as “synchronous motors” or “PMSMs”) have significantly improved performance and are small and highly efficient. Used in all industrial fields.

  A general PMSM has a rotating field structure in which a permanent magnet is provided on a rotor and an armature winding is provided on a stator. For PMSM control, it is necessary to detect the rotational angle position of the rotor. However, using a position sensor for this purpose is disadvantageous in terms of downsizing, noise resistance, and cost.

  Therefore, when an expensive position sensor cannot be used, or in an application that does not require high control accuracy and high-speed response, the magnetic pole position sensorless technology is indispensable. Various proposals have been made as methods for detecting the initial magnetic pole position when the synchronous motor is stopped.

  When supplying a voltage to a synchronous motor, a high frequency PWM inverter is generally used. In Non-Patent Document 1, the inductance is calculated from the harmonic current generated by the harmonics of the output voltage of the PWM inverter without superimposing a special voltage and current, and the magnetic pole position is estimated from the change. A method is disclosed in which a current that causes a saturation phenomenon is caused to flow again to determine the polarity of the magnetic pole position and to determine the magnetic pole position including the polarity.

  Also, in Non-Patent Document 2, unlike Non-Patent Document 1, self-inductance is calculated by performing Fourier transform from the voltage and current when the voltage is injected, and the magnetic pole position is estimated from the change. Similar to Patent Document 1, a method is disclosed in which a current is supplied to a motor to determine the polarity of a magnetic pole position to obtain a final magnetic pole position.

Satoshi Ogasawara, Takashi Matsuzawa, Yasufumi Akagi, “Position sensorless IPM motor drive system using position estimation method based on saliency”, IEEJ Proceedings, Vol. 118, No. 5, 1998 Osamu Yamaki, Takahiro Ara, “Initial magnetic pole position estimation method of surface magnet synchronous motor using pulse voltage”, IEEJ Proceedings D Vol. 125, No. 3 2005

  According to the conventional method described above, after calculating the inductance of the synchronous motor, the polarity of the magnetic pole is determined by flowing the current again by another means, and the final magnetic pole position is obtained. In other words, estimation of a non-polar magnetic pole position (for example, a value in the range of −π / 2 to π / 2) and polarity determination (determination of whether the magnetic pole is N or S) is performed by different means without considering the polarity. ing. For this reason, there is a problem that the configuration of the apparatus becomes complicated, the total calculation amount increases, the processing speed needs to be further increased, and the storage capacity needs to be increased. In addition, there is a problem that it takes time to detect the magnetic pole position because two-stage means of estimation of the magnetic pole position and polarity determination are used.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to perform estimation of the magnetic pole position and polarity determination in parallel at the same time, and to detect the magnetic pole position in a short time.

  In the present invention, the non-polar magnetic pole position and the polarity are simultaneously parallelized from the difference between the current circuit model of the synchronous motor called the adaptive model and the current value estimated by the adaptive model and the current value flowing through the actual synchronous motor. Thus, the magnetic pole position is detected by estimation.

  A detection device according to an embodiment of the present invention is a detection device of an initial magnetic pole position of a permanent magnet synchronous motor, and includes a power conversion unit for driving by driving a current through an armature winding, and flowing through the armature winding. A current detection unit for detecting current, a three-phase / two-phase coordinate conversion unit for converting the current detected by the current detection unit into a current in two-phase coordinates of the γ-axis and the δ-axis, and a voltage in the two-phase coordinates A voltage generation unit that generates a command, an adaptive model unit that obtains an estimated current value of the armature winding based on the voltage command in the two-phase coordinates, and a current in two-phase coordinates from the three-phase / two-phase coordinate conversion unit And the current estimation value obtained by the adaptive model unit, the position estimation unit for estimating the nonpolar magnetic pole position of the rotor, and the 3 in the case where the estimated magnetic pole axis estimated by the position estimation unit is the γ axis Γ from phase / 2 phase coordinate converter A current average unit for obtaining an average value of the current, an initial magnetic pole position detection unit for detecting an initial magnetic pole position based on the nonpolar magnetic pole position estimated by the position estimation unit and the average value from the current average unit, Have

  A detection method according to an embodiment of the present invention includes a step of passing a current through an armature winding based on a voltage command in two-phase coordinates of a γ axis and a δ axis, and detecting a current flowing through the armature winding. A step of performing coordinate conversion to a current in phase coordinates; a step of obtaining an estimated current value of the armature winding using an adaptive model based on the voltage command; a detected and coordinate-converted current and the estimated current value; A step of estimating the nonpolar magnetic pole position of the rotor, a step of obtaining an average value of the current of the γ-axis corresponding to the current flowing in the armature winding, the estimated nonpolar magnetic pole position and the average value And detecting an initial magnetic pole position based on

  A control device according to an embodiment of the present invention includes a voltage generation unit that generates a voltage command in two-phase coordinates of a γ-axis and a δ-axis based on a speed command, and a command value in three-phase coordinates based on the voltage command. A two-phase / three-phase coordinate conversion unit for converting the coordinates into the power, a power conversion unit for passing a current through the armature winding based on an output from the two-phase / three-phase coordinate conversion unit, and a current actually flowing through the armature winding. A current detection unit for detecting, a three-phase / two-phase coordinate conversion unit for converting the current detected by the current detection unit into a current in two-phase coordinates, and the electric machine using an adaptive model based on the voltage command. Estimating the rotational speed of the rotor from the adaptive model unit for obtaining the current estimation value of the cord and the current in the two-phase coordinates from the three-phase / two-phase coordinate conversion unit and the current estimation value obtained by the adaptive model unit Value and non-polar pole position estimation A current average unit for obtaining an average value of the current of the γ-axis from the three-phase / two-phase coordinate conversion unit when the estimated magnetic pole axis estimated by the position estimation unit is the γ-axis, and the estimation unit And an initial magnetic pole position detection unit that detects the initial magnetic pole position based on the estimated nonpolar magnetic pole position and the average value from the current averaging unit.

  According to the present invention, the estimation of the magnetic pole position and the polarity determination can be performed simultaneously in parallel, and the magnetic pole position can be detected in a short time.

It is a block diagram which shows the example of a structure of the detection apparatus of the initial stage magnetic pole position of this embodiment. It is an equivalent circuit of PMSM. It is a figure which shows the example of the pulse waveform of a voltage command. It is a figure for demonstrating the change of the synchronous inductance by an electric current. It is a figure for demonstrating a magnetic pole position. It is a block diagram of MRAS including a model error. It is a figure which shows the result of the simulation of estimation of a magnetic pole position. It is a figure which shows the waveform of each part in a demonstration experiment. It is a figure which expands and shows the pulse waveform of the voltage command in an experiment, and the waveform of an electric current. It is a block diagram which shows the example of a structure of the control apparatus of this embodiment. It is a flowchart which shows the outline of the processing operation of a control apparatus. It is a flowchart which shows the outline of the processing operation of initial magnetic pole position detection.

[Configuration of initial magnetic pole position detection device]
FIG. 1 shows a block diagram of a PMSM initial magnetic pole position detection device based on a model reference adaptive system (MRAS). 2 shows an equivalent circuit of PMSM, FIG. 3 shows an example of a pulse waveform of a voltage command, FIG. 4 shows a diagram for explaining a change in synchronous inductance due to current, and FIG. 5 shows a magnetic pole position. Each figure for explanation is shown.

  In FIG. 1, a PMSM (Permanent Magnet Synchronous Motor) is a rotating field type permanent magnet synchronous motor in which a rotor (rotor) is provided with a permanent magnet and a stator (stator) is provided with a three-phase armature winding. It is. The PMSM is not provided with a position sensor for detecting the magnetic pole position θ of the rotor. That is, it is sensorless.

  During normal rotation, the PMSM is frequency-controlled according to a speed command (rotational speed command) ω * (see FIG. 9), and rotates in synchronization with the frequency by the three-phase AC power Pout output from the power converter 15. Driven to rotate at speed ω.

  That is, in the PMSM basic model, as shown in FIG. 2, the direction of the N pole of the permanent magnet is the d-axis, and the direction advanced by π / 2 from this is the q-axis. That is, the d axis and the q axis are model axes. The lead angle of the d-axis relative to the U-phase armature winding is defined as θ. That is, the d-axis-q-axis coordinate system is at a position advanced by an angle θ from the U-phase armature winding as a reference.

  Θ represents the actual angular position (magnetic pole position) of the magnetic pole with respect to the U-phase armature winding. The angular position θ can also be obtained by integrating the rotational speed ω.

  The γ-axis is determined in correspondence with the estimated angle θ ^ of the magnetic pole position with reference to the U-phase armature winding. A position advanced by π / 2 in electrical angle from the γ axis is the δ axis. That is, the γ-axis δ-axis coordinate system is at a position advanced by an angle θ ^ with respect to the U-phase armature winding. Further, the d-axis-q-axis coordinate system and the γ-axis-δ-axis coordinate system are very close to each other, and θ and θ ^ are substantially equal, and adaptive control is performed in the vicinity of this equilibrium point.

  The U-phase, V-phase, and W-phase armature windings each have a self-inductance L including a leakage inductance l 'and an effective inductance L', and a winding resistance R.

  The self-inductance L (synchronous inductance) is proportional to the slope of the current-flux curve shown in FIG.

  When current flows through the armature winding, magnetic flux is generated. However, the magnetic flux of the armature winding is affected by the magnetic flux generated by the permanent magnet of the rotor. That is, plus or minus magnetic flux is added according to the magnetic pole position θ of the permanent magnet of the rotor, and this affects the self-inductance L of the armature winding, and the current in the positive or negative direction of the armature winding increases. Or decrease. In other words, when a current in the positive direction and a current in the negative direction are passed through the armature winding, one of the currents is added and increased, the other current is subtracted and decreased, and the average value thereof is positive. Shift in direction or negative direction.

  Therefore, a command is given to flow positive and negative currents with an average value of 0 through the armature winding, and the average value of the current that actually flows through the armature winding is taken to make the rotor permanent. It can be determined whether the magnetic pole of the magnet is N-pole or S-pole. That is, it can be determined whether the magnetic pole position θ of the permanent magnet of the rotor is in the range of −π / 2 to π / 2 or π / 2 to 3π / 2. Can be identified.

  Note that the command (voltage command V *) with an average value of 0 and the average value of the actually flowing current are on the same axis. In order to prevent the rotor from rotating when detecting the initial magnetic pole position θ ^, a high frequency voltage command V * is issued to either the γ-axis or the δ-axis, and the other is set to 0. Good.

  Further, an integrated value or an integrated value may be used as an average value of the current actually flowing through the armature winding. Moreover, such an average value should just be what can extract the shift amount of positive / negative electric current.

  The self-inductance L (synchronous inductance) is almost unchanged between the d-axis and the q-axis in a synchronous motor (SPMSM) having a surface magnet structure, and is not a salient pole machine. ), The q-axis is larger than the d-axis because it is a salient pole machine.

  In this specification, the symbol “*” is used to indicate a command or a command value for each parameter, and the symbol “^” is used to indicate an estimated value or a calculated value for each parameter.

  The detection device 3 of the present embodiment detects the initial magnetic pole position θ ^ of the PMSM rotor, that is, the magnetic pole position θ when the rotor is stopped (stationary).

  The detection device 3 includes a voltage generator 12 including a γ-axis voltage generator 12a and a δ-axis voltage generator 12b, a 2-phase / 3-phase coordinate converter 14, a power converter 15, a current detector 16, and a 3-phase / 2-phase. A coordinate conversion unit 17, an adaptive model unit 18, an estimation unit 19, a current averaging unit 21, an initial position detection unit 22, and the like are provided.

  The voltage generator 12 generates a voltage command V * in two-phase coordinates. That is, the γ-axis voltage generator 12a generates a γ-axis voltage command value Vγ * that is a γ-axis voltage command value, and the δ-axis voltage generator 12b is a δ-axis voltage command value that is a δ-axis voltage command value. Vδ * is generated.

  When detecting the initial magnetic pole position θ ^, the voltage generator 12 sets the δ-axis voltage command value Vδ * to 0, and repeats the γ-axis voltage command value Vγ * positively and negatively at a predetermined cycle high enough to prevent the rotor from rotating. Pulse voltage.

  That is, when detecting the initial magnetic pole position θ ^, the γ-axis voltage command value Vγ * is set to a pulse voltage Vp as shown in FIG. Further, as shown in FIG. 3B, the γ-axis voltage command value Vγ * is set to a constant value after gradually increasing the pulse voltage Vp and smoothly increasing the inclusion line in positive and negative directions. To do.

  The two-phase / three-phase coordinate conversion unit 14 performs coordinate conversion into a command value in three-phase coordinates based on the voltage command value V * in two-phase coordinates. That is, the γ-axis voltage command value Vγ * and the δ-axis voltage command value Vδ * from the voltage generation unit 12 are converted into three-phase voltage command values u, v, and w for controlling the power conversion unit 15. .

  The power conversion unit 15 includes a PWM control unit, an inverter, and the like, and drives the PMSM by passing a current through the value armature winding. That is, the power conversion unit 15 generates a PWM (Pulse Width Modulation) signal based on the output from the two-phase / three-phase coordinate conversion unit 14 and applies the PWM signal to each gate of the switching element of the inverter. The inverter outputs a three-phase AC power Pout with a controlled frequency and amplitude. This causes a three-phase current to flow through the PMSM u, v, and w armature windings, and the rotor is driven to rotate in synchronization therewith. The

  The current detector 16 detects a current flowing through the armature winding of the PMSM. That is, the actual current (current detection value) flowing through the PMSM is detected. In FIG. 1, the currents iu, iv, and iw flowing in the u, v, and w phases are detected. However, only one of the two phases may be detected, and the remaining one phase may be obtained by calculation. Good.

  The three-phase / 2-phase coordinate conversion unit 17 converts the current detected by the current detection unit 16 into a current in two-phase coordinates of the γ axis and the δ axis. That is, the three-phase currents iu, iv, iw from the current detector 16 are converted into a current iγ in the γ-axis direction and a current iδ in the δ-axis direction in the γ-δ axis coordinate system. Although the currents iγ and iδ are direct currents and converted, they correspond to the current that actually flows through the PMSM, and are also current detection values. Therefore, it may be described as “current detection values iγ, iδ”.

  The adaptive model unit 18 determines an estimated current value (current target value) of the armature winding based on the voltage command in the two-phase coordinates. That is, the adaptive model unit 18 performs adaptive control using the adaptive model (control model) based on the γ-axis voltage command value Vγ * and the δ-axis voltage command value Vδ * output from the voltage generator 12. , Current estimated values id ^ and iq ^ that are target values of the d-axis and q-axis currents are calculated.

  The adaptive model unit 18 can use an ideal control model from which interference is removed as the adaptive model. This will be described later with reference to FIG.

  The adaptive model used in the adaptive model unit 18 can represent the voltage-current equation by the following equation (4).

  The estimation unit 19 estimates the nonpolar magnetic pole position of the rotor from the current in the two-phase coordinates from the three-phase / two-phase coordinate conversion unit 17 and the estimated current value obtained by the adaptive model unit 18.

  That is, the estimation unit 19 determines the difference between the currents iγ and iδ detected by the current detection unit 16 and the current estimation values id ^ and iq ^ calculated by the adaptive model unit 18 (id ^ -iγ), (iq ^ The estimated nonpolar magnetic pole position θ ^ ± is obtained so that all of −iδ) asymptotically become zero.

  Here, the nonpolar magnetic pole position θ ^ ± means the magnetic pole position θ when the polarities of the N pole and S pole of the permanent magnet provided in the rotor are not taken into consideration. That is, in FIG. 5, when the direction of the N pole is the magnetic pole position (angle) θ, the magnetic pole position θ is in the range of 0 to 2π, and the magnetic pole position θ is specified in the range of the entire angle 2π for one rotation. . However, when the magnetic pole is not taken into consideration, the N pole and the S pole are in a point-symmetrical position with each other, and therefore, a range of an angle π for a half rotation, for example, a range such as 0 to π or −π / 2 to π / 2. , The magnetic pole position θ is specified. Such a nonpolar magnetic pole position is represented as “θ ^ ±” here.

  The estimation unit 19 can estimate the nonpolar magnetic pole position θ ^ ± of the rotor by the following equation (5).

Here, the non-polar magnetic pole position θ ^ ± is obtained by integrating the above equation (5). The initial value of the integration at this time is, for example, as shown in FIG. When 0, it may be 0.
In the γ-δ axis coordinate system, the PMSM magnetic pole axis estimated by the estimation unit 19 is the γ axis, and the axis advanced from the γ axis by an electrical angle of π / 2 is the δ axis.

  The estimated nonpolar magnetic pole position θ ^ ± is used for coordinate conversion in the 2-phase / 3-phase coordinate conversion unit 14 and the 3-phase / 2-phase coordinate conversion unit 17.

  The current averaging unit 21 obtains an average value Σi of the current iγ of the γ-axis (γ-axis direction) from the three-phase / two-phase coordinate conversion unit 17 when the estimated magnetic pole axis estimated by the estimation unit 19 is the γ-axis. . The average value Σi of the current iγ on the γ-axis indicates whether the sign is positive or negative of the magnetic pole of the rotor, that is, N pole or S pole. Therefore, the sign of the average value Σi is used to determine the polarity of the nonpolar magnetic pole position θ ^ ± estimated by the estimation unit 19.

  That is, a difference occurs in the inductance of the armature winding of the stator due to the influence of the magnetic flux of the permanent magnet of the rotor. As a result, the current value varies depending on the polarity of the current of the estimated magnetic pole axis (in this case, the γ axis), and this is used to determine the polarity of the nonpolar magnetic pole position θ ^ ±.

  The initial position detection unit 22 detects the initial magnetic pole position θ ^ based on the nonpolar magnetic pole position θ ^ ± estimated by the estimation unit 19 and the average value Σi from the current averaging unit 21. The initial magnetic pole position θ ^ is an estimated value of the magnetic pole position (angle) θ of the rotor when the PMSM rotor is stopped (stationary).

  When the average value Σi is positive (Σi> 0), the magnetic pole position is positive, and therefore the initial magnetic pole position θ ^ is an angle equal to the nonpolar magnetic pole position θ ^ ±. When the average value Σi is negative (Σi <0), the magnetic pole position is negative. Therefore, the magnetic pole position θ ^ is an angle obtained by adding or subtracting π to the nonpolar magnetic pole position θ ^ ± (θ ^ ± + π Or θ ^ ± −π).

  That is, the initial position detector 22 can obtain the initial magnetic pole position θ ^ by the following equation (6).

  The adaptive model unit 18 and the estimation unit 19 perform adaptive control based on the detected current values iγ and iδ and the voltage command values Vγ * and Vδ * so that the current error in the control model becomes asymptotically zero. These constitute the adaptive control unit TS.

  The adaptive control unit TS performs adaptive control so that the error is asymptotically zero. However, when the error is asymptotically zero, there is a sudden change so that the control is not disturbed. It means that control is done to avoid as much as possible.

  When detecting the initial magnetic pole position θ ^, the detection device 3 causes a current to flow through the armature winding based on the voltage command V * (γ-axis voltage command value Vγ * and δ-axis voltage command value Vδ *) and the armature winding. Is converted to currents iγ and iδ in two-phase coordinates. Based on the voltage command V *, current estimation values id ^ and iq ^ of the armature winding are obtained using an adaptive model.

  Then, the nonpolar magnetic pole position θ ^ ± of the rotor is estimated from the currents iγ and iδ that have been subjected to coordinate conversion and the current estimated values id ^ and iq ^. An average value Σi of the γ-axis current iδ corresponding to the current flowing through the armature winding is obtained and used for polarity determination. Based on the estimated nonpolar magnetic pole position θ ^ ± and the average value Σi, the initial magnetic pole position θ ^ is detected.

  As described above, in the detection device 3 of the present embodiment, a simple current circuit model of PMSM called an adaptive model is used, and current values id ^ and iq ^ estimated in the adaptive model and currents iγ and iδ that actually flow through the PMSM. From this difference, the magnetic pole position θ ^ is estimated.

  When the PMSM is rotating normally, the rotation speed is also estimated and controlled. Control is performed using the estimated rotational speed ω ^ and magnetic pole position θ ^ instead of the detection values obtained by the position sensor and speed sensor conventionally used.

  According to the present embodiment, the estimation of the magnetic pole position and the polarity determination can be performed simultaneously in parallel, and the detection of the magnetic pole position (initial magnetic pole position θ ^) can be performed in a short time. Therefore, the configuration of the apparatus is not complicated, and it is not necessary to increase the storage capacity and the calculation amount so much.

[Description of detection principle of initial magnetic pole position of detector]
Next, the detection principle of the initial magnetic pole position in the detection device 3 will be described.

  The voltage / current equation on the dq coordinate axis with the magnetic pole axis of the permanent magnet created by the rotor of the well-known permanent magnet synchronous motor as the d axis can be expressed by the following equation (7).

  Here, when detecting the initial magnetic pole position θ ^, since the rotor is in a stopped state, the rotational speed detection value ω may be set to 0 in the above equation (7). The state equation with the input variable at that time as the voltage value and the state variable as the current value is expressed by the following equation (8).

  The adaptive model unit 18 changes the current values id and iq to the current estimated values id ^ and iq ^ and changes the voltage values Vd and Vq to the voltage command values Vγ * and Vδ * in the state equation (8). (9) Calculate the equation.

  The adaptive model unit 18 calculates the equation (9) and outputs current estimation values id ^ and iq ^.

  The above equation (9) can be rewritten as the following equation (10).

  Based on the current estimation values id ^, iq ^ from the adaptive model unit 18 and the current detection values iγ, iδ from the three-phase / two-phase coordinate conversion unit 17, the estimation unit 19 generates a nonpolar magnetic pole position θ ^ ±. Is estimated.

  An embodiment for realizing the estimation unit 19 will be described below.

  The above equation (8) can be rewritten as the following equation (11).

  Assume that the U axis armature winding is the reference position, and the d axis that is the magnetic pole axis and the γ axis that is the magnetic pole estimation axis are shifted from the reference position by θ and θ ^, respectively. A conversion equation between the dq coordinate system and the γ-δ coordinate system can be expressed by the following equation (12).

  Further, the conversion formula R (θ−θ ^) can be expressed by the following formula (13).

  From the above equations (11) and (12), the following equation (14) can be obtained.

  Here, the δ-axis voltage command value Vδ * is set to 0, and the γ-axis voltage command value Vγ * is set to a pulsed high-frequency voltage as shown in FIG. 3 so that the rotor does not rotate. Further, when the estimation operation is stopped at the time of voltage application, the adaptive model unit 18 becomes the following equation (15) from the above equations (10) and (14).

  The PMSM current circuit model is expressed by the following equation (16).

  Current errors εγ and εδ between the estimated current values id ^ and iq ^ from the adaptive model unit 18 and the detected current values iγ and iδ from the three-phase / two-phase coordinate conversion unit 17 are expressed by the following equation (17).

  Then, the following expression (18) can be obtained from the above expressions (15), (16), and (17).

  Assuming that the current detection interval is sufficiently fast compared to the time constant of the current circuit,

  Therefore, the above equation (18) can be changed to the following equation (20).

  Here, δR = {cos (θ−θ ^) − 1} R is considered to be a variation in winding resistance, and an estimation rule for the magnetic pole position θ ^ when δR = 0 is obtained. When δR = 0, the above equation (20) becomes the following equation (21).

  The Lyabunov function V is expressed by the following equation (22).

  When the above equation (22) is differentiated, θ = constant, so that the following equation (23) is obtained.

  Substituting equation (21) into equation (23) above gives the following equation (24).

  In the above equation (24),

So

To be

If it is. Therefore, from the above equation (27), the estimation unit 19 may calculate the following equation (28).

The current averaging unit 21 determines the positive / negative by calculating the sum of the average value Σi ₊ of the positive current on the γ axis and the average value Σi ₋ of the negative current during estimation.

  The initial position detection unit 22 obtains the initial magnetic pole position θ ^ from the positive / negative signal from the current averaging unit 21 and the nonpolar magnetic pole position θ ^ ± from the estimation unit 19 by the following equation (29).

  In this way, the initial magnetic pole position θ ^ can be obtained. By using the obtained initial magnetic pole position θ ^ for setting the voltage command V * or the like when starting PMSM, PMSM can be started smoothly and quickly without reversing the rotor.

〔Stability〕
Here, the stability of the system is examined. The stability of the estimation system when δR ≠ 0 is obtained by the estimation rule of the above equation (28).

  FIG. 6 shows a block diagram of the control system when δR is considered as a model error or disturbance input.

  In the case of model errors and disturbances, it is known that in the estimation formula (28), the adaptive system becomes unstable due to drift caused by the nature of those signals. However, it is shown that when the forward control block is strongly positive and the error signal ε has PE property, the control block becomes stable. When this condition is applied to the magnetic pole position estimation system of Equations (20) and (28), the error equation satisfies a strong and positive reality with a first-order lag system, and positive and negative pulse signals with a constant period are continuously applied as identification signals. Therefore, the PE property of the error signal ε is also satisfied, and it is stable even if δR exists.

  The initial magnetic pole position θ ^ is estimated by (29) above. When it approaches the true value θ, θ−θ ^ approaches 0, and δR becomes 0 by δR = {cos (θ−θ ^) − 1} R. Become. For this reason, nothing needs to be done for δR.

[Simulation results]
FIG. 7 shows the result of simulation for estimating the initial magnetic pole position θ ^.

  FIGS. 7A and 7B show the results of estimating the initial magnetic pole position θ ^ by setting the magnetic pole position θ when the PMSM rotor is stationary to 30 degrees. It can be seen that in about 0.8 seconds, θ−θ ^ becomes 0 and the initial magnetic pole position θ ^ = 30 degrees is detected.

  FIGS. 7C and 7D show the results of estimating the initial magnetic pole position θ ^ by setting the magnetic pole position θ when the PMSM rotor is stationary to −85 degrees. It can be seen that in about 1.0 second, θ−θ ^ becomes 0, and the initial magnetic pole position θ ^ = − 85 degrees is detected.

〔Demonstration experiment〕
FIG. 8 shows the waveform of each part in the demonstration experiment, and FIG. 9 shows the voltage command pulse waveform and current waveform in an enlarged manner.

  The demonstration experiment was conducted using an actual machine. The PMSM parameters used in the experiment are as follows.

Number of poles: 4 poles, rated power: 1 Kw, rated current: 3.7 A, rated rotational speed: 2000 RPM, winding resistance: 1.1Ω, d-axis inductance: 8.05 mH, q-axis inductance: 9.78 mH
After shifting the magnetic pole position of the rotor by a predetermined angle, a high-frequency pulse voltage was applied only to the γ-axis so that the rotor did not rotate. Experiments were performed on 0, 45, 90, -45, -90, and 180 degrees as the angles for shifting the magnetic pole position. In the PMSM used in the experiment, a sensor for angle detection was attached in order to shift the magnetic pole position by a predetermined angle. The pulse voltage which is the voltage command value Vγ * on the γ axis has a frequency of 800 Hz and a pulse width of 0.25 ms.

  According to FIG. 8, it can be seen that even when any angle is shifted, after the detection of the initial magnetic pole position is started, it converges to 0 in about 30 to 100 ms.

  When the angle is 45 degrees, 90 degrees, and −45 degrees, the average value Σi (γaxis average current) of the current of the γ-axis that is the estimated axis is positive, and it can be determined that the magnetic pole is an N-pole. . When the angle is −90 degrees and 180 degrees, the average value Σi (γaxis average current) is also negative, and it can be determined that the magnetic pole is the S pole.

  For example, when the angle is 45 degrees, the difference (θ−θ ^) between the actual magnetic pole position θ and the estimated initial magnetic pole position θ ^ starts from 45 degrees and converges to 0 degrees in about 40 ms. .

  Also, when the angle is 90 degrees, the difference (θ−θ ^) between the actual magnetic pole position θ and the estimated initial magnetic pole position θ ^ starts from 90 degrees and converges to 0 degrees in about 80 ms. .

  When the angle is −90 degrees, the difference (θ−θ ^) between the actual magnetic pole position θ and the estimated initial magnetic pole position θ ^ starts from 270 degrees (−90 degrees), and is 180 after approximately 100 ms. It converges at a degree (-180 degrees). In this case, since the estimated magnetic pole position θ ^ is displaced from 270 degrees (−90 degrees) to 180 degrees (−180 degrees) with respect to −90 degrees of the magnetic pole position θ, the nonpolar magnetic pole positions θ ^ ± Is 90 (= 270-180) degrees. However, since the average value Σi (γaxis average current) is negative, the initial magnetic pole position θ ^ is obtained by adding 180 degrees to the nonpolar magnetic pole position 90 degrees according to the above equation (6), 270 degrees, that is, -90. This corresponds to the actual magnetic pole position θ.

  When the angle is −180 degrees, the difference (θ−θ ^) between the actual magnetic pole position θ and the estimated initial magnetic pole position θ ^ starts from 0 degrees and remains unchanged. In this case, since the estimated magnetic pole position θ ^ does not change at 0 degrees with respect to 180 degrees of the magnetic pole position θ, the nonpolar magnetic pole position θ ^ ± is 0 (= 0-0) degrees. However, since the average value Σi (γaxis average current) is negative, the initial magnetic pole position θ ^ becomes 180 degrees by adding 180 degrees to the nonpolar magnetic pole position 0 degrees according to the above equation (6). It coincides with the actual magnetic pole position θ.

  As described above, when the estimation operation for obtaining the nonpolar magnetic pole position θ ^ ± is completed, the magnetic pole direction is also determined, so that the initial magnetic pole position θ ^ is immediately obtained.

  As shown in FIG. 9, when a voltage waveform is applied suddenly when a voltage command is applied, the current iγ on the γ-axis temporarily shifts to one of positive and negative. In order to prevent this, the pulse voltage Vp may be gradually raised as shown in FIG.

[PMSM control device]
Next, the PMSM control device 1 will be described.

  FIG. 10 shows an example of the configuration of the control device 1 of the present embodiment.

  10, elements similar to those described above with reference to FIG. 1 are given the same reference numerals, and description thereof is omitted or simplified.

  The control device 1 includes a speed adjustment unit 11, a current adjustment unit (voltage generation unit) 12, a non-interference control unit 13, a 2-phase / 3-phase coordinate conversion unit 14, a power conversion unit 15, a current detection unit 16, and a 3-phase / 2. A phase coordinate conversion unit 17, an adaptive model unit 18, an estimation unit 19, a current averaging unit 21, and an initial position detection unit 22 are provided.

  The speed adjustment unit 11 performs speed adjustment based on a speed command (speed command value) ω *. That is, the δ-axis current command value iδ * is calculated based on the difference (ω * −ω ^) between the speed command value ω * input from the outside and the speed estimated value ω ^ output from the estimation unit 19. .

  That is, the speed adjustment unit 11 uses the difference (ω * −ω ^) between the speed command value ω * and the estimated speed value ω ^ as a deviation, and performs feedback control such as proportional / integral control (PI control) according to the speed command value. The δ-axis current command value (torque current command) iδ * is generated so that the rotation speed (actual rotation speed actual value) ω becomes (so that the deviation becomes zero).

  The current adjustment unit 12 includes a γ-axis voltage generation unit (γ-axis current adjustment unit) 12 a and a δ-axis voltage generation unit (δ-axis current adjustment unit) 12 b.

  During normal rotation of the PMSM, the γ-axis voltage generator 12a and the δ-axis voltage generator 12b perform current adjustment based on the γ-axis current command value iγ * or the δ-axis current command value iδ *, respectively. That is, the γ-axis voltage generator 12a calculates the γ-axis voltage command value Vγ * based on the difference (iγ * −iγ) between the γ-axis current command value iγ * and the detected γ-axis current value iγ. The δ-axis voltage generator 12b calculates the δ-axis voltage command value Vδ * based on the difference (iδ * −iδ) between the δ-axis current command value iδ * and the detected δ-axis current value iδ.

  In other words, the current adjusting unit 12 uses the differences (iγ * −iγ) and (iδ * −iδ) as deviations so that the current value becomes the command value by feedback control (so that the deviation becomes zero). An axis or δ-axis voltage command Vγ *, Vδ * is generated.

  When the PMSM is started from a stopped state, the γ-axis voltage generation unit 12a and the δ-axis voltage generation unit 12b are configured to detect the initial magnetic pole position θ ^ as described in FIG. The voltage command value Vδ * is set to 0, and the γ-axis voltage command value Vγ * is set to a pulse voltage that is repeated positively and negatively at a predetermined cycle high enough to prevent the rotor from rotating.

  The non-interference control unit 13 uses the voltage command (γ-axis voltage command value Vγ *, δ-axis voltage command value Vδ *) output from the current adjustment unit 12 and the estimated rotational speed (speed estimated value ω ^). Based on this, non-interference control for removing the interference is performed. That is, the non-interference control unit 13 determines that the γ-axis voltage command value Vγ *, the δ-axis voltage command value Vδ *, the γ-axis current detection value iγ, the δ-axis current detection value iδ, and the speed estimation value ω ^ An axis voltage command value Vγ ** and a δ axis voltage command value Vδ ** are calculated. The γ-axis voltage command value Vγ ** and the δ-axis voltage command value Vδ ** output from the non-interference control unit 13 interfere with the input γ-axis voltage command value Vγ * and δ-axis voltage command value Vδ *. Minutes have been removed.

  In the non-interference control unit 13, the interference component is a voltage component (back electromotive force) ωL, −ωL, ωφm, etc. induced in the inductance L of the armature winding along with the rotation of the PMSM rotor. is there. The inductance L and the rotor magnetic flux φm can be obtained in advance, and the interference can be obtained from these and the estimated value (speed estimated value) ω ^ of the rotational speed. When the PMSM is stopped, the rotational speed ω is 0 and no interference occurs.

  Non-interference control itself is a technique that has been used in the past. For example, Hidehiko Sugimoto, “Theory and Design of AC Servo Systems” (general electronic publisher, 1999/05/08, 77-80) Page).

  The adaptive model unit 18 uses an ideal control model from which interference is removed as the adaptive model. In this case, the adaptive model unit 18 calculates an estimated current value in an ideal current circuit of the PMSM without the influence of the back electromotive force proportional to the rotational speed ω of the PMSM.

  The estimation unit 19 determines the difference between the currents iγ and iδ detected by the current detection unit 16 and the current estimation values id ^ and iq ^ calculated by the adaptive model unit (id ^ -iγ), (iq ^ -iδ). ) Are asymptotically zeroed, and an estimated value (speed estimated value) ω ^ and a magnetic pole position estimated value (magnetic pole estimated value) θ ^ are obtained.

  The estimated speed value ω ^ obtained by the estimating unit 19 is used in the calculation of the δ-axis current command value iδ * in the speed adjusting unit 11.

  The estimation unit 19 is provided with an initial value storage unit 191 that stores an initial value θa of the magnetic pole position θ. The initial magnetic pole position θ ^ detected by the initial position detection unit 22 is stored in the initial value storage unit 191 as the initial value θa.

  By storing the initial value θa in the initial value storage unit 191, a voltage command V * corresponding to the initial value θa is output, and current is supplied to the armature winding so that the rotor can be started smoothly without being reversed. Will be washed away. As a result, PMSM can be started smoothly and quickly.

  In addition, after the initial value θa is stored in the initial value storage unit 191, the estimation unit 19 can obtain the magnetic pole position θ at an arbitrary timing, for example, by integrating the rotation speed.

[Explanation of processing operation by flowchart]
FIG. 11 shows a flowchart showing an outline of the processing operation of the control device 1, and FIG. 12 shows a flowchart showing an outline of the processing operation of the initial magnetic pole position detection.

  As shown in FIG. 11, at the time of start-up from the stop state, first, the initial magnetic pole position θ ^ is detected (# 11). The detected initial magnetic pole position θ ^ is set as the initial value θa in the estimation unit 19 and PMSM is started (# 12). Then, the currents iγ and iδ flowing through the armature winding of the PMSM are detected (# 13), and based on the voltage commands Vγ * and Vδ *, the estimated current values id ^ and iq ^ in the control model from which the interference is removed are calculated. (# 14).

  Then, the estimated value of the rotational speed is such that the difference (id ^ -iγ), (iq ^ -iδ) between the calculated current estimated values id ^, iq ^ and the detected current values iγ, iδ asymptotically becomes zero. ω ^ and the estimated value θ ^ of the magnetic pole position are obtained (# 15), and speed control and coordinate conversion are performed based on the obtained estimated value ω ^ of the rotational speed and the estimated value θ ^ of the magnetic pole position (# 16).

  In FIG. 12, an initial pulse is generated based on the voltage command V * (# 21). The current flowing through the armature winding is detected (# 22), and the coordinates are converted into currents iγ and iδ in two-phase coordinates (# 23). The adaptive model is used to obtain armature winding current estimation values id ^, iq ^ (# 24). The nonpolar magnetic pole position θ ^ ± of the rotor is estimated from the currents iγ, iδ and the current estimation values id ^, iq ^ (# 25). An average value Σi of the γ-axis current iδ is obtained (# 26), and the initial magnetic pole position θ ^ is detected based on the estimated nonpolar magnetic pole position θ ^ ±.

  In the embodiment described above, in the synchronous motor having the embedded magnet structure, the q-axis inductance Lq is larger than the d-axis inductance Ld (Lq> Ld), and the initial magnetic pole position θ ^ can be easily detected. In the case of a synchronous motor with a surface magnet structure, when a current that causes magnetic saturation is passed through the armature winding, the inductance decreases, and a difference appears between the inductance Ld of the magnetic flux axis and the inductance Lq of the torque axis, and the initial magnetic pole The position θ ^ can be easily detected.

[Others]
In the embodiment described above, the detection of the initial magnetic pole position θ ^ when the rotor is stopped (stationary) has been described. However, the rotor is not necessarily stationary, and may be rotating at a low speed that is not affected by the counter electromotive force. That is, even at an extremely low speed, the magnetic pole position θ ^ can be detected using the detection device 3 or the control device 1 of the above-described embodiment.

  Other components of PMSM, voltage generation unit 12, non-interference control unit 13, adaptive model unit 18, estimation unit 19, current averaging unit 21, initial position detection unit 22, detection device 3, or control device 1, or the entire configuration, The structure, circuit, shape, method, number, calculation content, processing content, processing order, and the like can be appropriately changed in accordance with the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Control apparatus 3 Detection apparatus 12 Voltage generation part 13 Non-interference control part 14 2 phase / 3 phase coordinate conversion part 15 Power conversion part 16 Current detection part 17 3 phase / 2 phase coordinate conversion part 18 Adaptive model part 19 Estimation part 21 Current Average unit 22 Initial position detector (initial magnetic pole position detector)
θ ^ Initial magnetic pole position θ Magnetic pole position θ ^ ± Nonpolar magnetic pole position iγ Current of γ-axis (current detection value)
i δ δ-axis current (current detection value)
id ^ d-axis estimated current value iq ^ q-axis estimated current value Vγ * γ-axis voltage command value Vδ * δ-axis voltage command value Σi average value

Claims (9)

An apparatus for detecting an initial magnetic pole position of a permanent magnet synchronous motor,
A power conversion unit for driving by driving current through the armature winding;
A current detector for detecting a current flowing in the armature winding;
A three-phase / two-phase coordinate conversion unit that converts the current detected by the current detection unit into a current in two-phase coordinates of the γ-axis and the δ-axis;
A voltage generator for generating a voltage command in two-phase coordinates;
An adaptive model unit for obtaining an estimated current value of the armature winding based on a voltage command in the two-phase coordinates;
A position estimation unit that estimates a non-polar magnetic pole position of the rotor from the current in the two-phase coordinates from the three-phase / 2-phase coordinate conversion unit and the current estimation value obtained by the adaptive model unit;
A current averaging unit for obtaining an average value of the current of the γ-axis from the three-phase / two-phase coordinate conversion unit when the estimated magnetic pole axis estimated by the position estimation unit is the γ-axis;
An initial magnetic pole position detection unit that detects an initial magnetic pole position based on the nonpolar magnetic pole position estimated by the position estimation unit and an average value from the current average unit;
A device for detecting an initial magnetic pole position of a permanent magnet synchronous motor, comprising: An adaptive model for estimating the current estimation value in the adaptive model unit is represented by the following equation (1):

The detection apparatus of the initial magnetic pole position of the permanent-magnet synchronous motor of Claim 1. The position estimation unit estimates the nonpolar magnetic pole position θ ^ ± of the rotor by the following equation (2):

The detection apparatus of the initial magnetic pole position of the permanent-magnet synchronous motor of Claim 2. The initial magnetic pole position detector
Based on the nonpolar magnetic pole position θ ^ ± from the position estimation unit and the average value Σi from the current average unit, the initial magnetic pole position θ ^ is detected by the following equation (3):

The detection apparatus of the initial magnetic pole position of the permanent-magnet synchronous motor in any one of Claim 1 thru | or 3. The voltage generation unit, when detecting the initial magnetic pole position,
The δ-axis voltage command value Vδ *, which is the δ-axis voltage command value, is set to 0,
A γ-axis voltage command value Vγ *, which is a voltage command value for the γ-axis, is a pulse voltage that is repeated positively and negatively at a predetermined cycle high enough to prevent the rotor from rotating.
The detection apparatus of the initial magnetic pole position of the permanent-magnet synchronous motor in any one of Claims 1 thru | or 4. A method for detecting an initial magnetic pole position of a permanent magnet synchronous motor,
passing a current through the armature winding based on a voltage command in the two-phase coordinates of the γ-axis and the δ-axis;
Detecting current flowing through the armature winding and converting the current into current in two-phase coordinates;
Obtaining an estimated current value of the armature winding using an adaptive model based on the voltage command;
Estimating a non-polar magnetic pole position of the rotor from the detected and coordinate-converted current and the current estimation value;
Obtaining an average value of γ-axis current corresponding to the current flowing through the armature winding;
Detecting an initial magnetic pole position based on the estimated nonpolar magnetic pole position and the average value;
A method for detecting an initial magnetic pole position of a permanent magnet synchronous motor. A voltage generator that generates a voltage command in two-phase coordinates of the γ-axis and the δ-axis based on the speed command;
A two-phase / three-phase coordinate conversion unit for converting the coordinates into a command value in three-phase coordinates based on the voltage command;
A power conversion unit for passing a current through the armature winding based on the output from the two-phase / three-phase coordinate conversion unit;
A current detector that detects a current that actually flows through the armature winding;
A three-phase / two-phase coordinate conversion unit for converting the current detected by the current detection unit into a current in two-phase coordinates;
Based on the voltage command, an adaptive model unit for obtaining a current estimation value of the armature winding using an adaptive model;
An estimation unit for estimating an estimated value of the rotational speed of the rotor and a non-polar magnetic pole position from the current in the two-phase coordinates from the three-phase / two-phase coordinate conversion unit and the estimated current value obtained by the adaptive model unit; ,
A current averaging unit for obtaining an average value of the current of the γ-axis from the three-phase / two-phase coordinate conversion unit when the estimated magnetic pole axis estimated by the position estimation unit is the γ-axis;
An initial magnetic pole position detection unit that detects an initial magnetic pole position based on the nonpolar magnetic pole position estimated by the estimation unit and an average value from the current average unit;
A control device for a permanent magnet synchronous motor, comprising: In the stopped state of the rotor,
The voltage generator sets a δ-axis voltage command value Vδ *, which is a δ-axis voltage command value, to 0, and a γ-axis voltage command value Vγ *, which is a γ-axis voltage command value, is high enough to prevent the rotor from rotating. A pulse voltage that repeats positive and negative at a predetermined cycle,
The initial magnetic pole position detected by the initial magnetic pole position detection unit at this time is set as an initial value of the magnetic pole position in the estimation unit,
The controller for a permanent magnet synchronous motor according to claim 7. A non-interference control unit that performs non-interference control for removing interference based on the voltage command and the estimated value of the rotation speed;
The controller for a permanent magnet synchronous motor according to claim 7 or 8.

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