JP2000312493A - Sensorless control system for permanent magnet synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensorless control system which can surely estimate the positions of the magnetic poles of a permanent magnet synchronous motor with high accuracy when the motor is stopped. SOLUTION: A voltage vector generating means 11 impresses positive and negative voltage vectors of a fixed voltage upon a motor 1 at different angles, while the motor 1 is in a stop state and a current detecting means 12 detects the d-axis current values on fixed coordinates with respect to the impressed voltage vectors. A sensorless control system estimates the final positions of the magnetic poles of a permanent magnet synchronous motor by repetitively operating a first estimating means 13, which estimates the positions of the voltage vectors at which the difference between the d-axis current values becomes largest, when roughly angle-changed voltage vectors are generated as the approximate positions of the magnetic poles and a second estimating means 14, which estimates the positions of the voltage vectors at which the difference between the d-axis current values becomes largest, when finely angle- changed voltage vectors are generated as the positions of the magnetic poles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensorless control system for a permanent magnet type synchronous motor such as a PM motor or a brushless motor, and more particularly to a magnetic pole position for detecting a magnetic pole position in a stopped state of the motor without using a position sensor. It relates to an estimation device.

[0002]

2. Description of the Related Art A control device for a permanent magnet type synchronous motor performs torque control by applying a current to an armature winding according to the position of a magnetic pole of a rotor. Therefore, a position sensor such as an encoder or a resolver is generally provided. ing. However, these position sensors cause an increase in the size and cost of the motor control system, and have problems in reliability and environmental resistance. Therefore, research on a sensorless control method that does not require a position sensor has been actively conducted.

[0003] Currently proposed methods of estimating the magnetic pole position when the motor is stopped can be broadly classified as follows.

(1) A method in which the inductance of a salient pole type motor is changed depending on the position of a magnetic pole, and estimation is performed using a voltage-current relationship on two-axis coordinates.

(2) A method in which the inductance of a salient pole type motor is changed depending on the position of a magnetic pole, and estimation is performed using voltage information when an alternating current is injected.

(3) A method of estimating using the peak current value at the time of applying a pulse voltage, utilizing the fact that the inductance of a salient pole type motor changes depending on the magnetic pole position.

(4) A method of estimating from a current vector locus when a high-frequency voltage is applied, utilizing the fact that the inductance of a salient pole type motor changes depending on the position of a magnetic pole.

(5) A method in which a conductive non-magnetic material is pasted on the rotor surface of a cylindrical motor, and the magnetic pole position at the time of stop is estimated.

[0009]

Most of the conventional sensorless control systems are based on motor model formulas, and utilize the fact that the inductance of a salient-pole type motor varies depending on the magnetic pole position. Is obtained.

However, in the case of a cylindrical motor, there is generally little difference between the inductance values of the d-axis and the q-axis.
With the estimation from the model formula, the magnetic pole position and the like cannot be estimated at the time of starting or stopping the motor, and the torque is reduced at the time of starting the motor, and a large reversal occurs temporarily.

An object of the present invention is to provide a motorless sensorless control system capable of accurately and reliably estimating the magnetic pole position of a permanent magnet type synchronous motor when stopped.

[0012]

(Principle of the Invention) FIG. 10 shows a PM motor model of a two-pole machine. The axis of the stator winding is α-β coordinate, the axis fixed to the rotor is dq coordinate, and the d axis is in the direction of the magnetic flux generated by the field. Further, an axis estimated by the estimating device side is d _e -q _e coordinates, the actual position angle theta _re, [Delta] [theta] angular difference between the estimated position angle theta _M, d-axis and d _e axis
And

The voltage equation on the α-β coordinate axis of the stator winding in the above general motor model is as follows.

[0014]

(Equation 1)

Here, vα and vβ are the armature voltages α and β
Axis components, iα and iβ are the α and β axis components of the armature current, R is the armature resistance, L _d and L _q are the d and q axis inductance components,
p represents a differential operator.

As shown in the above equation, in the salient pole type motor, the stop
Even at standstill, due to the difference in d and q axis inductance,
Position angle information is 2θ_reExists in the form of trigonometric functions. Only
The absolute position (d-axis direction) including the field polarity is
Estimate from general mathematical model as shown in the equation
Can not do. Further, a cylindrical motor is generally L _d
= L_q= L, the above equation is
From this mathematical model, the position at rest is
No angle information can be obtained.

[0017]

(Equation 2)

The present invention utilizes the non-linearity of the magnetization characteristics of the armature core in a PM motor in order to estimate the magnetic pole position at the time of stoppage. The non-linearity determines the magnetic pole position from the difference in current response depending on the magnetic pole position. It is an estimate.

FIGS. 11 (a) to 11 (c) show positive and negative constant voltages (rated 7 voltages) for the u, v, and w phases of the PM motor, respectively.
5%) is applied for a time of 200 μs, and the current value of each phase is measured at every 10 ° position angle of the rotor.
I _u ⁺ shown in FIG. 3A indicates a u-phase current value when a positive voltage is applied to the u-phase and a negative voltage is applied to the v and w-phases. Also, I _u ^- indicates a negative voltage to the u phase, a positive voltage v, the u-phase current value when applied to the w-phase. Similarly, (b) and shown in ^{_{(c) I v +, I}} v - and I _w ^+, I _w ^- denotes the v, and w-phase current value when a voltage is applied to each phase. Note that the negative current values I _u ⁻ , I _v ⁻ and I _w ⁻ are represented by absolute values so that the magnitudes can be easily compared.

The measurement results shown in FIG.
From the equation, θ where the polarity of the field near the u-phase winding is N_re=
In the vicinity of 0, when a voltage is applied in the magnetizing direction,
When a positive voltage is applied, the magnetic flux saturates and the inductor
Current I _u ⁺Time change is large
You. Conversely, when a negative voltage is applied, the inductance
Does not increase or change, the current I_u ^-The time change of
It is smaller than when a positive voltage is applied. Also,
θ where the polarity of the field near the u-phase winding is S_re= 180
In the vicinity of °, the current I_u ⁺Current I_u ^-Changes over time
growing.

FIG. 11D shows a difference Δ between current values of the respective phases.
I_u(= I_u ⁺+ I_u ^-), ΔI_v(= I _v ⁺+ I_v ^-), ΔI_w
(= I_w ⁺+ I_w ^-). From the result of FIG._uIs θ
_re= 0 ° and 180 ° around 0.1 °
There is a difference,_vIs θ_re= With 120 ° and 300 °
There is a difference near, ΔI_wIs θ_re= Around 240 ° and 60 °
There is a difference. That is, the current value difference ΔI_u, Δ
I_v, ΔI_wNear the polar axis
There is a difference in the current value.

The difference between the current values of these phases appears because the magnetic flux is saturated due to the non-linearity of the magnetization characteristics of the armature core with respect to the applied voltage, and the inductance is reduced.
Therefore, by utilizing the fact that the difference between the current values in the magnetizing direction and the demagnetizing direction near the polar axis becomes large, the magnetic pole at the time of stoppage is detected by detecting the voltage vector position where the current value difference becomes the largest. The position can be estimated. From this,
The present invention has the following features.

(First invention) In a sensorless control system of a permanent magnet synchronous motor for controlling a voltage angle supplied to an armature winding of the permanent magnet synchronous motor in accordance with a magnetic pole position of the permanent magnet synchronous motor, the motor is stopped. In this state, a voltage vector of a constant positive and negative voltage whose angle is changed at regular intervals is applied to the motor, and a d-axis current value of coordinates fixed to the rotor with respect to the application of each positive and negative voltage vector is detected. And a magnetic pole position estimating device for estimating, as a magnetic pole position, a position of the voltage vector in which the difference between the two is largest.

(Second Invention) In the first invention, the accuracy of the estimated magnetic pole position is determined by the angular interval of the voltage vector, and the smaller the angular interval, the higher the accuracy. The number of outputs increases and the estimation process takes time. Therefore, the present invention divides the estimation of the magnetic pole position into a plurality of stages of rough estimation and fine estimation to reduce the number of times of estimation processing and time, and has the following configuration.

When the motor is stopped, the magnetic pole position estimating device applies a d-axis of coordinates fixed to the rotor when a voltage vector of constant positive and negative voltages whose angles are roughly changed at regular intervals is applied to the motor. A first method for estimating the position of the voltage vector where the difference between the current values is the largest as the approximate magnetic pole position
The difference between the d-axis current value when applying a voltage vector whose angle is finely changed at regular intervals to the electric motor around the voltage vector position detected by the first estimating means and the voltage vector position detected by the first estimating means is the most significant. A second estimating means for estimating a final magnetic pole position by repeating a process of estimating the position of the voltage vector which becomes large as a magnetic pole position.

(Third invention) In the above-mentioned first estimating means,
And the actual magnetic pole position θ_reIs around 90 ° or -90 °
, The respective d-axis current values I_d1, I_d7Almost different
May not appear. This example is shown in Table 1 below.
Value I_d1, I_d7And its difference | I_d1-I _d7|
You.

[0027]

[Table 1]

[0028] Theoretically, -90 ° <θ _re <90 For _{° I d1> I d7, θ} re = 90 ° or -90 For ° I _d1 = I _d7, other in the case of I _d1 Although it should be <I _d7 , there is “variation” as shown in Table 1 above, and the difference is very small.

This is because when the magnetic pole position is around 90 ° and -90 °, the influence of magnetic saturation is small and the change in inductance is small, so that there is almost no difference in the d-axis current value. It is considered that an error has occurred due to the influence of the accuracy of the measurement and noise.

Accordingly, the present invention provides a method for controlling the case where the difference | I _d1 −I _d7 | between the absolute values of the d-axis current values I _d1 and I _d7 is within an error range (for example, 0.03 amps in the above table). Then, instead of estimating the approximate magnetic pole position in the first estimating means, the following estimation is performed.

First, the voltage vectors v ₄ and v ₁₀ of 90 ° and −90 ° in FIG. 12 are applied to the motor, and the d-axis current I _d detected in the same manner as in the estimation 1 is applied to this voltage application. _{Is the} estimated magnetic pole position θ _M1 , and its current is I _dmax .

As a result, the actual magnetic pole position θ _re is
Can be estimated by the voltage theta _M1 ± 15 ° of accuracy with respect to the vector, as shown in Table 1, the magnetic pole position theta _re 9
The difference | I _d1 −I _d7 | between the absolute values is also small around 0 ° ± 15 ° and around −90 ° ± 15 °.

[0033] Therefore, further, as shown in FIG. 13, based on the estimated magnetic pole position theta _M1, the voltage vector v ₁₃ and v ₁₄ position of ± 15 ° is applied to the motor, the d-axis current for this application By comparing the absolute value difference, the estimated magnetic pole position θ
Update _M1 . The magnetic pole position is narrowed down by the second estimating means with respect to the updated estimated magnetic pole position θ _M1 . From the above, the present invention is characterized by the following configuration.

The magnetic pole position estimating device may be configured such that the magnetic pole position estimated by the first estimating means is close to 90 ° or −90 °.
In the case of near, the position of the voltage vector where the difference of the d-axis current value when the voltage vector having a certain angular difference before and after the estimated magnetic pole position is applied to the electric motor with respect to the estimated magnetic pole position is the largest is determined. It is characterized by comprising means for updating as a position.

[0035]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention. The PM motor (permanent magnet type synchronous motor) 1 is supplied with current to the armature winding by the PWM inverter 2 and is operated synchronously. PWM inverter 2
, An on / off control signal for the main circuit switch is applied from the drive circuit 3.

The current detectors 5U and 5V detect U- and V-phase currents supplied to the PM motor 1.

The controller 4 controls the angle of the drive signal to the drive circuit 3 according to the estimated magnetic pole position,
From the detected currents from the current detectors 5U and 5V, the PM motor 1
Is controlled by controlling the winding current.

The rotary encoder 6 coupled to the PM motor 1 is provided for observing fluctuations in the rotor position, and is not provided in an actual sensorless control system.

Here, in this embodiment, the PM in the stopped state
As means for estimating the magnetic pole position of the motor 1, the controller 4 includes a voltage vector generating means 11, a current detecting means 12, first and second estimating means 13 and 14, and a control means 15 for controlling these means. Provide.

The voltage vector generating means 11 includes the control means 1
Under the control of 5, a positive / negative voltage vector whose angle is changed every 30 ° as shown in FIG. 12 is sequentially generated, and further, the voltage whose angle is changed before and after the estimated magnetic pole position θ _M as a reference. Generate vectors sequentially. These voltage vectors are
The PWM inverter 2 applies the changed angle voltage to the PM motor 1 in the stopped state.

The current detecting means 12, the current I _n ⁺ of flowing through the armature winding by the positive and negative voltage is applied to the PM motor 1, I _n ^- detected.

First estimating means 13 and second estimating means 14
Cooperates with the motor 1 to apply a constant positive / negative voltage vector having an angle changed at a constant interval to the motor 1 while the motor 1 is stopped, and to obtain d d of a coordinate fixed to the rotor for the application of each positive / negative voltage vector The shaft current value is detected, and the position of the voltage vector where the difference between the current values is largest is estimated as the magnetic pole position.

The first estimating means 13 applies, to the motor, a voltage vector of a constant positive and negative voltage whose angle is roughly changed at a constant interval to the motor when the motor is stopped. The d-axis current value of the coordinates fixed to the child is detected, and the position of the voltage vector where the difference between the current values is the largest is estimated as the approximate magnetic pole position. This estimation process will be described in detail below.

[0044] First, ⁺ current I _n to be detected by the current detecting means 12, I _n ^- into a d-q coordinates at an angle of a voltage vector, detects two d-axis current value I _d, greater of which square of the voltage vector position estimated magnetic pole position theta _M1, the current value I _d at that time to the maximum d-axis current value I _{dma x.} This estimate is
It is determined whether the magnetic pole is on the magnetic side or the demagnetizing side, and the magnetic pole position is estimated on which side of the positive or negative voltage vector.

[0045] Then, estimated to using the estimated magnetic pole position theta _M1 and the maximum d-axis current value I _dmax whether there is actual magnetic pole position theta _re in either direction before and after the voltage vector position where the estimated magnetic pole position theta _M1 . FIG. 2 shows this estimation processing procedure.

In FIG. 2, I _dn is a d-axis current value when the voltage vector n in FIG. 12 is output. Also, i and j are determination coefficients used for ending the estimation. In the process of FIG. 2, first, i = 1, j = 1, and n = 0 are initially set (S1), and _{n is set} as a voltage vector vn to be applied.
= Θ _M1 / 30 ° + 2j is determined (S2). That is, I
The voltage vector becomes _{dma x} determines the voltage vector v _n of switching 30 °. In this determination, when n ≦ 0, n = n + 12.

Next, the voltage vector v determined in step S2
_n is outputted (S3), and it is determined whether or not the d-axis current I _dn detected by the current detecting means 12 with respect to this voltage vector is I _dn > I _dmax (S4).

[0048] In this determination, if the I _dn> I _dmax, the voltage vector v _n of the angle (n-1) × 30 ° the estimated magnetic pole position theta _M1, and updates the current I _dn at that time as I _dmax, Also, i = 0 (S5).

In the above judgment, when I _dn ≦ I _dmax , i = j
It is determined whether or not = 1 (S6). If i = j = 1, j =
0, and if i = j = 1, end the estimation process (S
7).

[0050] At the end of step S5 also S7, unless n = 4 or n = 10, returns to the process S2, performs the comparison of the current I _dn and I _dmax by changing the voltage vector v _n to be applied (S
8).

The above estimation processing is performed, for example, when the voltage vector at which the estimated magnetic pole position θ _M1 and the maximum d-axis current value I _dmax are obtained is v ₁ in FIG. 12, the processing in steps S2 to S5 and S8 is repeated. _As long as _dn > _Idmax continues, the voltage vector is switched to v ₂ and further to v ₃ , and the estimated magnetic pole position θ _M1 and the maximum d-axis current value I _dmax are updated, and the search and update of the closest voltage vector position are repeated. Then, in these processes, I _dn ≦
When it is I _dmax, it stops searching the voltage vector is estimated as the magnetic pole position of the closest approximately the voltage vector v _n of the actual magnetic pole position theta _re at this time.

With the above processing, the angle of the voltage vector n closest to the actual magnetic pole position θ _re becomes the estimated magnetic pole position θ _M1 . In these first estimating means, the voltage vector is set to 30 °
Magnetic pole position θ _re is θ _M1 ±
It can be estimated with an accuracy of 15 °.

However, as described above, the magnetic pole position θ _re is 9
In the vicinity of 0 ° or −90 °, there _may be little difference between the respective d-axis current values I _d1 and I _d7 . Therefore, in the first estimating means 13, the magnetic pole position θ _re is 90 °
Or, in the case of about −90 °, as shown in FIG. 13, a fixed angle difference (for example, ± 1) with reference to the estimated magnetic pole position θ _M1.
The voltage vector v _13, v ₁₄ position of 5 °) is applied to the motor, and updates the estimated magnetic pole position theta _M1 by comparing the difference between the absolute value of the d-axis current for this application. In the case of FIG. 13, the magnetic pole position θ _re can be estimated with an accuracy of ± 7.5 °.

Returning to FIG. 1, the second estimating means 14 applies to the motor 1 a voltage vector whose angle has been finely changed at regular intervals around the voltage vector position detected by the first estimating means. The process of estimating the position of the voltage vector at which the difference of the d-axis current value with respect to the application of the voltage vector becomes largest as the magnetic pole position is repeated to estimate the final magnetic pole position.

In the example of the first estimating means 13, since the actual magnetic pole position θ _re is estimated with an accuracy of θ _M1 ± 15 ° or less, first, the second estimating means 14 uses ( As shown in a), a voltage vector v ₁ 'v ₂ ' at an angle of θ _M1 ± 7.5 ° was applied to the motor 1 and a voltage vector n was applied in the same manner as the first estimating means 13. The new estimated magnetic pole position θ _M1 is determined by comparing the current d-axis current I _dn . Further, based on this determination, as shown in FIG.
_M1 Voltage vectors v ₃ ′, v ₄ ′ at an angle of ± 3.75 °
_Is applied to the motor 1 to obtain θ _M21 . Similarly, θ _M22 based on the voltage vectors v ₅ ′ and v ₆ ′ is obtained based on θ _M21 as shown in FIG. By repeating these processes, it is estimated that to match the estimated magnetic pole position theta _M actual magnetic pole position theta _re high accuracy.

In the estimating apparatus described above, for example, a voltage vector is output at a magnitude of 75% of the rating for 200 μs, and after outputting each voltage vector, all gate signals are turned off for 600 μs. Each phase current is set to zero, and the next voltage vector is output from the same state.

As described above, in the present embodiment, since the magnetic pole position is estimated based on the current response to the voltage vector applied to the motor 1 in the stopped state, the magnetic pole position is surely not affected by the setting error or fluctuation of the motor constant. The position can be estimated.

An experiment for verifying the estimation device of the present invention was conducted. Incidentally, PM motor 1, rated capacity 400W, maximum rated voltage 152V, the maximum rated current 1.9A, synchronous speed 50H _Z, the maximum rotational speed 3000 rpm, pole Use a four-pole, resolution 400 to the rotary encoder 6
Magnetic pole position estimation was performed using the one with 0 p / r.

FIGS. 4 to 9 show experimental results, and FIG. 4 shows changes in the d-axis current _Idn and its maximum value _Idmax when estimation is performed at the actual magnetic pole position θ _re = 54 °. . I _dn is a d-axis current when the voltage vector n is applied. First,
The initial estimate by the first estimation means, the current I _n ^+,
I _n ^- the voltage vector v ₁ and v ₇ obtained as, for the actual magnetic pole position θ _re = 54 °, the d-axis current I _d1> I _d7. Therefore, the angle 0 ° of the voltage vector v ₁ becomes the estimated magnetic pole position θ _M1 , and I _d1 becomes I _dmax .

The next estimation by the first estimating means 13 (see FIG. 2)
Processing), first, the voltage vector v _Two, And in FIG.
Is I_d2> I_dmaxSo that θ_M1Is updated to 30 °
You. Further, the voltage vector v_ThreeAnd I_d3> I_dmax
So that θ_M1Is updated to 60 °. Finally, the voltage
Vector v_FourIs applied, but I_d4<I_dmaxIs
, Θ_M1Ends the processing by the first estimating means without being updated.
Complete. At this time, the estimated magnetic pole position θ_M1Is the actual magnetic pole position
θ_re= Voltage vector v closest to 54 °_ThreeAngle of 60 °
become.

Next, in the second estimation means 14, by sequentially switching the application of the voltage vector v ₁ of FIG. 3 'to v _6', the final estimation result theta _M2 of voltage vector v ₁ ' The angle was 52.5 °. The current value of each phase at this time is 20
FIG. 5 shows the results of sampling at 0 μs intervals. As shown in the figure, the current value immediately decreases after the application of the voltage vector, and all of the voltage vectors are applied from almost the same state of zero current.

[0062] Figure 6 shows the change in I _dn and I _dmax in actual magnetic pole position θ _re = 36 °. In the first estimation means 13, next to the angle -30 ° is theta _M1 of the voltage vector v _12,
In the second estimating means, the d-axis current value I _d4 when the voltage vector v ₄ ′ is applied becomes I _dmax , and θ _M2 becomes −33.75.
° was obtained.

Similarly, FIGS. 7 and 8 show actual magnetic poles, respectively.
Position θ_re= I at 99 ° and -81 ° _dnAnd I_dmaxChange
Show. In each case, the actual magnetic pole position θ_reBut
D-axis current values near 90 ° and -90 °
I_dFig. 2
, The estimated magnetic pole position θ_M1Before that
Later, the estimation by applying a voltage vector with a certain angular difference
Done, each θ_M1105 ° -75 °, θ_M21
01.25 ° -86.25 °.

FIG. 9 shows that the actual magnetic pole position θ _re is changed from 0 ° to 9
The respective estimation results when a total of 41 points are set up to 360 ° every ° are shown. The result is an average error of 4.13 °,
The magnetic pole position could be estimated with a maximum error of 16.88 °. The time required for estimation is 9.1 m at the maximum.
s, the minimum was 7.4 ms. Further, the winding current value during the estimation was about 80% of the maximum at the maximum, but no displacement of the rotor was recognized in any case.

[0065]

As described above, according to the present invention, the magnetic pole position of the permanent magnet type synchronous motor is estimated by utilizing the non-linearity of the magnetization characteristics of the armature core. There is an effect that the estimation can be performed with high accuracy.

Further, since the approximate magnetic pole position is estimated in the first estimating process and the magnetic pole position is finely estimated in the second estimating process, the number of estimation processes can be reduced and the estimation time can be shortened.

Further, even when the magnetic pole position is near 90 ° or −90 °, the magnetic pole position can be reliably estimated.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

FIG. 2 is an exemplary flowchart of an estimation process performed by a first estimation unit according to the embodiment;

FIG. 3 is a voltage vector diagram based on magnetic pole positions θ _M1 , θ _M21 and θ _M22 estimated by a second estimating means in the embodiment.

FIG. 4 is a position estimation characteristic (θ _re = 54 °) showing experimental results based on the present invention.

FIG. 5 is a graph showing changes in the current value of each phase (θ _re = 54 °) showing experimental results based on the present invention.

FIG. 6 shows position estimation characteristics (θ _re = 36 °) showing experimental results based on the present invention.

FIG. 7 is a position estimation characteristic (θ _re = 99 °) showing an experimental result based on the present invention.

FIG. 8 is a position estimation characteristic (θ _re = −81 °) showing an experimental result based on the present invention.

FIG. 9 is a magnetic pole position estimation characteristic showing experimental results based on the present invention.

FIG. 10 is a PM motor model

FIG. 11 shows a current value of each phase when a voltage is applied to explain the present invention in principle.

FIG. 12 shows a voltage vector n (1 to 12) according to the present invention.

FIG. 13 is a voltage vector diagram based on an estimated magnetic pole position θ _M1 .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... PM motor 2 ... PWM inverter 3 ... Drive circuit 4 ... Controller 5U, 5V ... Current detector 6 ... Rotary encoder 11 ... Voltage vector generation means 12 ... Current detection means 13 ... First estimation means 14 ... Second estimation Means 15 ... Control means

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takashi Kodama 2359-8 Kiyosu-cho, Nishi-Kasugai-gun, Aichi Prefecture 203 Clecent Laurel 203 (72) Inventor Kenji Yamada 92, Higashisugaguchi, Shinkawa-cho, Nishi-Kasugai-gun, Aichi 103F Sun Life Shinkawa Terms (reference) 5H560 BB04 BB12 DA07 DC12 EB01 GG04 TT15 XA05 XA12 XA13 5H576 BB10 CC01 DD02 EE11 GG01 GG04 HB01 JJ17 LL22

Claims (3)

[Claims] 1. A sensorless control system for a permanent magnet synchronous motor that controls a voltage angle supplied to an armature winding of the permanent magnet synchronous motor according to a magnetic pole position of the permanent magnet synchronous motor. A voltage vector of a constant positive / negative voltage whose angle is changed at intervals is applied to the electric motor, and a d-axis current value of coordinates fixed to the rotor with respect to the application of each positive / negative voltage vector is detected. A sensorless control system for a permanent magnet synchronous motor, comprising: a magnetic pole position estimating device for estimating a position of the increasing voltage vector as a magnetic pole position. 2. The magnetic pole position estimating apparatus according to claim 1, wherein, when the motor is stopped, a voltage vector of a constant positive and negative voltage whose angle is roughly changed at a constant interval is applied to the rotor when the motor is stopped. first estimating means for estimating the position of the voltage vector at which the difference between the d-axis current values is the largest as an approximate magnetic pole position, and at regular intervals around the voltage vector position detected by the first estimating means, Estimating the final magnetic pole position by repeating the process of estimating the position of the voltage vector at which the difference of the d-axis current value becomes the largest when the voltage vector whose angle is finely changed is applied to the electric motor is the magnetic pole position The sensorless control system for a permanent magnet type synchronous motor according to claim 1, further comprising a second estimating unit. 3. The magnetic pole position estimating device, wherein when the magnetic pole position estimated by the first estimating means is near 90 ° or near −90 °, the magnetic pole position is estimated to be constant before and after the estimated magnetic pole position. 3. The apparatus according to claim 1, further comprising means for updating, as a magnetic pole position, a position of the voltage vector at which a difference between the d-axis current values when a voltage vector having an angle difference is applied to the motor is maximized. 2. A sensorless control system for a permanent magnet synchronous motor according to claim 1.