JP2000175483A - Sensorless control method for synchronous motor and its apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct simple, highly accurate sensorless control of a synchronous motor, with only two current sensors, regardless of the presence of salient polarity. SOLUTION: In this method (apparatus), the angle of a rotor θ' is computed based on detected current values In-fb, Iv-fb and voltage command values Vu, Vv of two phases of a three-phase brushless DC motor 1 and by using the computed angle of a rotor θ', the motor 1 is controlled with 180-degree sine wave. In this control, the actual angle of a rotor θ of the motor 1 is inferred, based on the computed angle of the rotor θ', and by using this inferred angle of the rotor θ the motor 1 is controlled with a 180-degree sine wave. Thus, simple and highly accurate sensorless control of the motor 1 can be performed with only two current sensors, regardless of the presence of salient polarity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for calculating a rotor angle of a synchronous motor comprising a three-phase stator winding and a rotor having a permanent magnet based on two-phase detected current values and voltage command values. The present invention relates to a synchronous motor sensorless control method and apparatus for controlling the synchronous motor using the calculated rotor angle, and particularly to a three-phase brushless DC motor used for a compressor of an air conditioner unit. It is suitable for the sensorless control of.

[0002]

2. Description of the Related Art Conventionally, AC servomotors and brushless D
In a synchronous motor such as a C motor, it is necessary to flow a stator current that depends on the rotor position.
As shown in (b), position sensors such as encoders and Hall elements have been used. However, these position sensors have disadvantages such as hindering downsizing of the motor and being susceptible to the vibration of the motor. Especially for use in compressors of air conditioner units, control is performed without a sensor. It is desirable. Therefore, various technologies related to sensorless control have been developed as follows. For example, Japanese Patent Application Laid-Open
-256496 and IEEJ Journal Vol. 11
8-D, no. In 7/8, '98 (pp. 828 to 835), the voltage and current applied to the stator winding of the three-phase brushless DC motor are detected, and the rotor is estimated based on the detected voltage and current, respectively. A technique for driving an inverter circuit based on the position and angular velocity information to control a three-phase brushless DC motor with a 180-degree sine wave is disclosed. Japanese Patent Application Laid-Open No. 8-308286 discloses a synchronous motor utilizing the fact that the deviation between the rotation angle of a model of a synchronous motor having salient poles and the actual rotation angle is proportional to the deviation between the actual current and the model current. A technique related to sensorless control of a synchronous motor for estimating a rotation angle of a rotor of the motor has been disclosed.

[0003]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 8-256
496 and IEEJ Journal Vol. 118-D,
No. 7/8, '98 (pp. 828 to 835), a rotor angle and a rotor speed are estimated based on voltage and current feedback for two phases of a three-phase brushless DC motor, and the motor is thereby estimated. It is necessary to use two current sensors and two voltage sensors in order to control the temperature with a 180-degree sine wave with high accuracy, and there is room for further reducing the number of sensors. Further, the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-308286 uses only two current sensors, but cannot be applied to a synchronous motor having no salient poles in the motor. The present invention has been made to solve such a problem, and converts a rotor angle calculated based on detection values from two current sensors into, for example, a change value of the rotor angle per predetermined time. By estimating the actual rotor angle of the synchronous motor, the synchronous motor can be easily and accurately controlled with only two current sensors regardless of the presence or absence of salient poles. It is an object of the present invention to provide a sensorless control method and a device for a motor. However, even when the actual rotor angle of the synchronous motor is estimated from the rotor angle calculated based on the detection values from the two current sensors as described above, an estimation error occurs due to a calculation error and the like.
The control accuracy may be adversely affected. Therefore, another object of the present invention is to estimate the instantaneous angular velocity and the average angular velocity, which is the average value, from the calculated rotor angle, and calculate the estimated instantaneous angular velocity and average angular velocity, and the calculated rotor speed. The estimation error is suppressed by estimating the actual rotor angle of the synchronous motor based on the angle,
It is an improvement to further improve the control accuracy.

[0004]

According to a first aspect of the present invention, there is provided a synchronous motor comprising a three-phase stator winding and a rotor having a permanent magnet. In a synchronous motor sensorless control method of calculating a rotor angle based on a voltage command value and controlling the synchronous motor using the calculated rotor angle, the synchronous motor is controlled based on the calculated rotor angle. And a sensorless control method for the synchronous motor characterized by controlling the synchronous motor using the estimated rotor angle. With such a configuration, the rotor angle of the synchronous motor is calculated based on the detected current value and the voltage command value of the two phases, and the actual rotor angle of the synchronous motor is estimated based on the calculated rotor angle. Therefore, the estimated rotor angle does not include noise or error. By controlling the synchronous motor using the estimated rotor angle, sensorless control of the synchronous motor can be easily and accurately performed using only two current sensors regardless of the presence or absence of salient poles. Further, in the first invention, an instantaneous angular velocity and an average angular velocity which is an average value thereof are estimated from the calculated rotor angle, and the estimated instantaneous angular velocity and average angular velocity are calculated. By estimating the actual rotor angle of the synchronous motor on the basis of the angle (corresponding to claims 8 and 9), adverse effects such as calculation errors occurring when estimating the rotor angle are suppressed, and the accuracy of sensorless control is reduced. It can be further improved. According to a second aspect of the present invention, a synchronous motor comprising a three-phase stator winding and a rotor having a permanent magnet is rotated based on two-phase detected current values and voltage command values. In a synchronous motor sensorless control device comprising a rotor angle calculating means for calculating a rotor angle and controlling the synchronous motor using the calculated rotor angle, the rotor angle calculating means comprises A speed electromotive force calculator for calculating a speed electromotive force based on the detected current value and the voltage command value; a rotor angle calculator for calculating a rotor angle based on the calculated speed electromotive force; A rotor angle estimator for estimating an actual rotor angle of the synchronous motor based on a rotor angle, and controlling the synchronous motor using the estimated rotor angle. Electric motor It is configured as Nsaresu controller. With such a configuration, it is possible to obtain an apparatus that can execute the above first invention method.

[0005]

Embodiments of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
It should be noted that the following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention. FIG. 1 is a block diagram showing the overall configuration of a sensorless control device for a synchronous motor according to an embodiment of the present invention,
FIG. 2 is a hardware configuration diagram of the apparatus, FIG. 3 is a flowchart showing a schematic operation in a sensorless routine of the apparatus, and FIG. 4 is a flowchart showing a schematic operation in a startup routine of the apparatus.

As shown in FIG. 1, a sensorless control method for a synchronous motor according to the present embodiment (hereinafter, referred to as “this method”) is a three-phase brushless DC motor (corresponding to a synchronous motor, hereinafter referred to as “motor”). )) Two-phase detected current value Iu fb, Iv This is the same as the conventional example in that the rotor angle θ ′ is calculated based on fb and the voltage command values Vu and Vv, and the motor 1 is controlled by a 180-degree sine wave using the calculated rotor angle θ ′. However, in the present method, the actual rotor angle θ of the motor 1 is estimated based on the calculated rotor angle θ ′, and the motor 1 is controlled by a 180-degree sine wave using the estimated rotor angle θ. It differs from the conventional example in the point.

[0007] An apparatus for realizing the present method (hereinafter, "the present apparatus")
That. 2), as shown in FIG. 2, is composed of a motor 1, a power inverter 2, and a speed controller 30 in terms of hardware configuration. Among them, the motor 1 is a motor having no salient poles, which is composed of a three-phase stator winding and a rotor having a plurality of permanent magnets. The power supply inverter 2 is a power supply 3 for converting AC to DC by a rectifier circuit. And an inverter device 4 that generates three-phase alternating current with six thyristors
And a current detecting device 5 such as a shunt resistor. Further, the speed control device 30 includes various arithmetic devices, a main storage device, and the like for realizing the control block as shown in FIG.
A DSP (Digital) equipped with an external signal input / output device and a power supply device for these operations (both are not shown in FIG. 2).
tal Signal Processor), etc., and an angle estimating device (corresponding to a rotor angle calculating means) 1
0, a current control device 20 and the like. Hereinafter, each component of the apparatus will be described in detail with reference to FIG.

(1) Angle Estimating Device 10 In FIG. 1, the angle estimating device 10 further includes a uvw phase → α─β axis converter 11, a speed electromotive force calculator 12, a rotor angle calculator 13, An estimated rotor angle calculator (corresponding to a rotor angle estimator) 14 is provided. (A) uvw phase → α─β axis converter 11 The uvw phase → α─β axis converter 11 calculates α─β using the following equation.
Perform axis conversion. That is, the voltage command values Vu, Vv, Vw
And the current feedback Iu fb, Iu From fb,
The α─β axis voltages Vα, Vβ and the α─β axis currents Iα, Iβ are calculated. Vα = √ (2/3) × (Vu−Vv / 2−Vw / 2) (1) Vβ = √2 / 2 × (Vv−Vw) (2) Iα = √ (2/3) × ( Iu fb-Iv fb / 2-Iw fb / 2) (3) Iβ = √2 / 2 × (Iu fb-Iw fb) (4) Vw = −Vu−Vv (5) Iw fb = −Iu fb-Iv fb ... (6)

(B) Speed electromotive force calculator 12 The speed electromotive force calculator 12 calculates the speed electromotive force e using the following equation.
Calculate α, eβ. Here, Vα and Vβ are voltage command values, Iα (n) and Iβ (n) are current feedback at sampling time n, T is sampling time, R is resistance value of one motor phase, and L is one motor phase. Is the inductance value. eα = Vα−R × Iα (n) −L / T × {Iα (n) −Iα (n−1)} (7) eβ = Vβ−R × Iβ (n) −L / T × {Iβ ( n) −Iβ (n−1)｝ (8) (c) Rotor angle calculator 13 The rotor angle calculator 13 calculates the rotor angle θ ′ using the following equation.
Is calculated. θ ′ = tan− ¹ (−eα / eβ) (9) where the above equation (9) is derived from the following equation. here,
ω is an angular velocity, and φf is an induced voltage coefficient. eα = −ωφf × sin θ ′ (10) eβ = + ωφf × cos θ ′ (11)

(D) Estimated rotor angle calculator 14 The estimated rotor angle calculator 14 estimates the estimated rotor angle θ as follows, for example. Here, the estimation of the estimated rotor angle θ is based on the fact that if the rotor angle θ ′ is left as it is, there are many noises and errors, so that using the corrected estimated rotor angle θ to drive the motor more efficiently Because it can be.
The present invention has been made in view of such a point, and for example, correction is performed using the following equation. dθ ′ / dt = {θ ′ (Ta) −θ ′ (Tb)} / (Ta−Tb) (12) θid = K × Id (13) θ (n) = θ (n−1) + θid + dθ ′ / Dt × T (14) where dθ ′ / dt is the time differential value of the rotor angle, θ ′
(Ta) is the angle of the rotor at the time Ta, θ ′ (Tb) is the angle of the rotor at the time Tb, and θ (n) is the time n of the rotor.
, Θ (n−1) is the angle of the rotor at time n─1, T is the sampling time, θid is the correction amount of the rotor angle, and K is the coefficient. Id is the current feedback Iu. fb, Iu It is a feedback value of the q-axis current based on fb.
This is the output of the vw phase → dq axis converter 22. Here, the feedback Id of the q-axis current is used to calculate the estimated rotor angle θ.
Is used for the feedback I of the q-axis current.
This is to take advantage of the characteristic that the motor 1 is accelerated when a negative current flows through d. In addition, by switching the rotor angle θ ′ and the estimated rotor angle θ in some cases, control can be performed even in a state where the load condition is worse.

(2) Power control device 20 and the like In FIG. 1, the power control device 20 includes an estimated speed calculating section (corresponding to rotor speed calculating means) 21 and a uvw phase → d−
q-axis converter 22, dq-axis current controller 23, dq
Axis non-interference control unit (corresponding to dq axis non-interference control means) 24
, Dq axis → uvw phase converter 25, and PWM controller 2
6 and a speed control unit 31 outside the device.
And the power supply inverter device 2. The power inverter device 2 is provided with a six-phase PWM from the power control device 20.
(Pulse Width Modulation) signal, and is a device capable of outputting a three-phase voltage to the motor 1.
Further, the current Iu fb, Iv A current detecting device 5 for fb detection is provided. Here, for convenience of explanation, the current Iu is fb, Iv Although fb is detected, it is equivalent to the circuit of the present apparatus. (A) Estimated Speed Calculation Unit 21 The estimated speed calculation unit 21 calculates the estimated speed N from the estimated rotor angle θ using, for example, the following equation. Here, P is the number of motor poles, θ (Ta) is the estimated rotor angle at time Ta,
θ (Tb) is the estimated rotor angle at time Tb. N = 1 / (2πP) × {θ (Ta) −θ (Tb)} / (Ta−Tb) (15)

(B) Speed control unit 31 The speed control unit 31 compares the speed command Nref with the estimated speed N, uses general PI control, and uses the q-axis current command I
q Calculate ref. (C) uvw phase → dq axis converter 22 The uvw phase → dq axis converter 22 calculates the current feedback Iu of the power inverter 2 using the following equation. fb, Iv
The dq-axis current feedback Id, Iq is calculated from fb and the estimated rotor angle θ. Id = √ (2/3) × ｛cos θ × (Iu fb-Iv fb / 2-Iw f b / 2) + √3 / 2 × sin θ × (Iv fb-Iw fb)｝ (16) Iq = √ (2/3) × ｛−sin θ × (Iu fb-Iv fb / 2-Iw fb / 2) + √3 / 2 × cos θ × (Iv fb-Iw fb)｝ (17) Since the dq-axis current feedbacks Id and Iq cannot be directly observed (not observable), the above calculation is performed.

(D) dq axis current control section 23 The dq axis current control section 23 receives a signal from the speed control section 31.
Q-axis current command Iq ref and dq axis current feed
Dq axes (not shown) with back Id and Iq
The voltage commands Vd 'and Vq' are calculated. Here, dq
Calculation using general PI control is performed for each axis. Sand
The purpose of the dq axis non-interference control unit 24 described below is
Control the current, the dq axis current control unit 23
Is the q-axis current command Iq ref and dq current feed
By comparing the back Id and Iq, the next q-axis current command Iq r
ef '(not shownShow). This q-axis current command I
q To dq axis voltage commands Vd 'and Vq' after ref '
This is because voltage conversion is performed. The above reason
For this reason, the dq-axis current control unit 23 controls the dq-axis current control.
When performing control, current feedback is performed. (E) dq-axis non-interference control unit 24 The dq-axis non-interference control unit 24 calculates the dq-axis
From the pressure commands Vd 'and Vq', the d-q axis voltage command Vd r
ef, Vq Calculate ref. Vd ref = Vd′−ω × L × Iq (18) Vq ref = Vq ′ + ω × (φf + L × Id) (19) ω = 2π / 60 × P × N (20)

(F) dq axis → uvw phase converter 25 dq axis → uvw phase converter 25 calculates dq
Shaft voltage command value Vd ref, Vq The uvw-phase voltage commands Vu, Vv, Vw are calculated from ref. Vu = √ (2/3) × (Vd ref × cos θ−Vq ref × sin θ) (21) Vv = √ (１ ／) × ｛(− Vd ref × cos θ + Vq ref × sin θ) + √3 × (Vd ref × sin θ + Vq ref × cos θ)｝ (22) Vw = √ (１ ／) × ｛(− Vd ref × cos θ + Vq ref × sin θ) −√3 × (Vd ref × sin θ + Vq ref × cos θ)｝ (23) (g) PWM control unit 26 The PWM control unit 26 is a device that receives the three-phase voltage commands Vu, Vv, and Vw and generates a six-phase PWM signal. Dead time for shifting the ON timing between the upper and lower thyristors can be created.
This function is provided as standard on the PWM generation device.

Hereinafter, the operation of the present apparatus will be described with reference to FIGS. (1) Sensorless Routine In FIGS. 1 and 3, when the synchronous motor is controlled by the sensorless routine in a 180-degree sine wave control, the current detection device 5 uses u,
The current flowing in the v-phase is detected (step S1), and the uvw-> α─β-axis conversion unit 11 detects the current feedback Iu flowing in the detected u and v-phases. fb, Iv w-phase current Iw remaining from fb fb, and the uvw-phase voltage commands Vu, Vv, Vw, and the α-β axis currents Iα, Iβ and α
-Β-axis voltages Vα and Vβ are converted (step S2).
The speed electromotive force calculation unit 12 calculates the speed electromotive forces eα and eβ on the α axis and β axis from the current feedback Iα and Iβ on the α-β axis, the voltage commands Vα and Vβ, and the motor model (step S3). The child angle calculator 13 calculates the rotor angle θ ′ from the phase difference between the two-axis speed electromotive forces eα and eβ (step S4). As described above, since the calculated rotor angle θ ′ includes noise and error and needs to be corrected, the estimated rotor angle calculation unit 14 determines the rotor angle θ ′, the current feedback The estimated rotor angle θ is calculated using Id (step S5). The rotation direction of the rotor can be obtained from the rotor angle θ ′, but can be obtained more easily by using the estimated speed N.

Next, the uvw phase → dq axis converter 22
Is the current feedback Iu of the uvw phase using the estimated rotor angle θ. fb, Iv fb is converted into dq-axis current feedback Id, Iq (step S6).
The dq-axis current control unit 23 includes a dq-axis current feedback Id, Iq and a q-axis current command Iq output from the speed control unit 31. ref and a dq-axis current control calculation for calculating dq-axis voltage commands Vd 'and Vq' is performed (step S7). The dq axis non-interference controller 24 calculates d
Dq-axis voltage command V, which is the calculation result of q-axis current control
Using d ′ and Vq ′, dq axis voltage command Vd re
f, Vq ref is calculated, and the calculated values of the estimated speed N based on the estimated rotor angle θ are combined to perform the dq axis non-interference control calculation (step S8). The dq-axis → uvw phase converter 25 converts the dq-axis voltage command Vd, which is the result of the dq-axis non-interference control calculation. ref, Vq The three-phase voltage commands Vu, Vv, Vw are calculated from ref (step S9). Then, the PWM control unit 26 outputs the three-phase voltage commands Vu, Vv, V
A PWM signal is output from w to drive the power inverter device 2 to realize current control with a 180-degree sine wave of the motor 1 (step S10). On the other hand, the estimated speed calculating unit 21 calculates the estimated speed N from the estimated rotor angle θ obtained in step S5 (step S11), and the speed control unit 31
Calculates the speed control calculation by associating the estimated speed N with the speed command Nref and calculating the q-axis current command Iq output ref,
This is set as a command of the current control device 20 in step S7 (step S12). Steps S1 to S1
By repeating Step 2, sensorless control of the motor 1 can be performed.

(2) Startup Routine When the motor 1 is started up, the speedless electromotive forces eα and eβ are small, so the sensorless routine cannot be used. For example, a well-known startup routine as shown in FIG. 4 is used. That is, the start routine is controlled in an open loop, and receives a motor start signal (not shown) to generate a sine wave voltage in three phases (step S21). Then, the motor 1 starts rotating at the point of time when the synchronization is properly made (step S22). When the motor 1 starts to rotate, the speed electromotive forces eα and eβ are generated, so that the rotor angle θ and the rotor speed N can be estimated (step S23). When such a state is reached, the above-described sensorless routine is started (step S24). Note that the escape from the sensorless routine is performed when the estimated speed has decreased to the threshold value. As described above, the rotor angle of the synchronous motor is calculated based on the two-phase detected current value and the voltage command value, and the actual rotor angle of the synchronous motor is estimated based on the calculated rotor angle. Therefore, the estimated rotor angle does not include noise or error. By controlling the synchronous motor using the estimated rotor angle, sensorless control of the synchronous motor can be performed simply and accurately with only two current sensors. In this embodiment,
From the viewpoint that a motor with no ripple is desirable for higher precision control, sensorless control of a motor without salient poles has been exemplified. However, the scope of the present invention is not limited to this, and it is not limited to the conventional example. The present invention is sufficiently applicable to a motor having salient poles. Also, in the present embodiment, from the viewpoints of downsizing the device and obtaining a higher calculation speed, etc.
Although the DSP is used as the hardware configuration, a commercially available microcomputer having the same capability can be used.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When the estimated rotor angle is obtained by the estimated angle calculating section 14, as another example, it can be corrected by interpolation calculation using the following equation. dθ ′ / dt = {θ ′ (Ta) −θ ′ (Tb)} / (Ta−Tb) (20) θ (n) = θ (n−1) + dθ ′ / dt × T (21) , Dθ ′ / dt is the time derivative of the rotor angle, θ ′
(Ta) is the angle of the rotor at the time Ta, θ ′ (Tb) is the angle of the rotor at the time Tb, and θ (n) is the time n of the rotor.
, Θ (n−1) is the angle of the rotor at time n─1, and T is the sampling time. The above equation (21) is equivalent to equation (14) when Id = 0 in equation (13).
This is consistent with the equation, and the sensorless control of the motor 1 can be realized more easily than in the above-described embodiment, so that the present invention can be applied to a case where accuracy does not matter much.

The basic contents of the present invention are as follows.
In the techniques described in the above embodiments and examples, the instantaneous speed
Obtain the rotor angle of the motor from the voltage and perform further estimation
But the periodic angle caused by calculation errors and noise
Error may not be negligible, in which case
Is the above angle when performing current control by three-phase-dq calculation.
Error estimates the ripples on the d-axis current and the q-axis current,
Control accuracy may be degraded. This angle estimation error causes
In order to suppress the deterioration of control accuracy due to
In the estimated rotor angle calculation unit 14, the following equation (22) is used.
Then, the estimated rotor angle may be obtained. P {θ (n + 1)} = θ ′ (n) + K₁× M [P {ω (n)}] × T−K_Two× E (n) × T = θ ′ (n) −K_Two× P {ω (n)} × T + (K₁+ K_Two) × M [P {ω (n)}] × T (22) P {ω (n)} = {θ ′ (n) −θ ′ (n−1)} / T (23) M [P {Ω (n)}] = LPF [P {ω (n)}] (24) E (n) = P {ω (n)} − M [P {ω (n)}] (25) , T is the sampling time, K₁, K_TwoAre each
0 <K₁<2,0 <K _Two<2 constant, P {ω (n)} is
The estimated value of the instantaneous angular velocity ω (n), M [P {ω (n)}] is
The average value of the estimated value of the instantaneous angular velocity ω (n), E (n) is
LPF is the estimated instantaneous error angle at time n.
Low-pass with cut-off frequency characteristics about the time constant
Represents a filter. Estimate rotor angle as above
The configuration of the sensorless control device for the synchronous motor is shown in FIG.
This is shown in the diagram. Note that FIG. 5 is the same as the above embodiment.
FIG. 1 shows the configuration of a sensorless control device for a starting motor.
And the same components in both figures
Have the same reference numerals, and the same
Symbols with "" added to the numbers are given.

In the following, the sensorless control device for a synchronous motor according to the present embodiment (device for realizing the method according to the eighth and ninth aspects) will be described focusing on differences from the device according to the above embodiment. Do. When the rotor angle calculator 13 calculates the rotor angle θ ′ (n) at time n using the above equation (9), the rotor angle θ ′
(N) is provided to both the rotor angle estimator 14 'and the estimated angular velocity calculator 21'. Estimated angular velocity calculator 2
1 ′, the change amount θ ′ of the rotor angle per sampling time T based on the above equations (23) and (24).
(N) −θ ′ (n−1), that is, an estimated value P {ω (n)} of the instantaneous angular velocity ω (n), and an average angular velocity M which is a time moving average of the estimated value P {ω (n)} [P {ω (n)}] is obtained and supplied to the rotor angle estimator 14 '. The average angular velocity M [P {ω (n)}] is also supplied to the speed control unit 31 of the speed control device 30, and the speed control unit 31 _adds the average angular velocity M to the speed command ωref.
Feedback control by general PI control is performed so that [P {ω (n)}] coincides, and the q-axis current command I
q ref is required. The rotor angle estimator 14 '
Then, the estimated value P {ω (n)} and the average angular velocity M [P {ω (n)}] of the instantaneous angular velocity ω (n) supplied from the estimated angular velocity calculation unit 21 ′, and the rotor angle calculation Based on the rotor angle θ ′ (n) supplied from the unit 13, the estimated value of the rotor angle P （θ (n
+1)｝ is required. This estimated rotor angle P 角度 θ
(N + 1)}, the estimated value P {ω (n)} of the instantaneous angular velocity ω (n) and the average angular velocity M [P {ω (n)}]
, The estimated instantaneous error angle E (n) obtained by using the above equation (25) is subtracted. As a result, the influence of high-frequency components due to calculation errors, noise, and the like is removed from the estimated rotor angle value P {θ (n + 1)}. The estimated value of the rotor angle P ｛θ from which the influence of the high-frequency component caused by the calculation error and the noise has been removed as described above.
(N + 1)} is the uvw phase of the current controller 20 → d−q
It is supplied to the axis converter 22 and the dq axis → uvw phase converter 25. Therefore, the uvw phase → dq axis conversion unit 22
-D-axis current feedback Id, Iq output from
As for, the ripple caused by the calculation error and the noise can be suppressed, and the control accuracy can be further improved.

Next, referring to FIG. 5 and FIG.
Of Sensorless Control System for Synchronous Motor
explain. FIG. 6 shows the synchronous power supply according to the above embodiment.
In the sensorless routine of the sensorless control device of the motive
FIG. 4 is a flowchart corresponding to FIG.
The same steps are denoted by the same reference numerals. Figure
In 5 and 6, the synchronous motor is set to 1
When performing the 80-degree sine wave control, the current detection device 5
The current flowing in the phase is detected (step S1), and the uvw phase →
The α─β axis converter 11 detects the current flowing in the detected u and v phases.
Feedback Iu fb, Iv The remaining w-phase from fb
Current Iw Calculate fb and voltage command of them and uvw phase
Vu, Vv, and Vw are defined as α-β axis currents Iα, Iβ and α-β
It is converted into β-axis voltages Vα and Vβ (step S2). Speed
The electromotive force calculation unit 12 performs current feedback on the α-β axis.
From Iα, Iβ, voltage commands Vα, Vβ and the motor model, α
Calculate the speed electromotive force eα, eβ in the axis and β axis (step
S3) The rotor angle calculation unit 13 performs the speed electromotive of the two axes.
Calculate the rotor angle θ ′ from the phase difference between the forces eα and eβ
(Step S4). Next, the estimated angle calculator 21 '
Is the instantaneous angle based on the rotor angle θ ′ calculated above.
Estimated value P {ω (n)} of velocity ω (n) and average angular velocity
M [P {ω (n)}] is obtained, and the rotor angle estimating unit 14 ′ is obtained.
(Step S41). Rotor angle estimator
14 ′, the estimated value P ｛ω of the instantaneous angular velocity ω (n)
(N)} and average angular velocity M [P {ω (n)}] supplied
Then, the rotor angle estimating unit 14 'calculates the rotor angle
Of the estimated value P {θ (n + 1)} (step S
5). At this time, as described above, the estimation of the instantaneous angular velocity ω (n) is performed.
Constant value P {ω (n)} and average angular velocity M [P {ω (n)}]
From this difference, the estimated instantaneous error angle E (n) is obtained.
Of the rotor instantaneous error E (n)
It is removed from the value P {θ (n + 1)}. Then uv
The w-phase → dq-axis conversion unit 22 calculates the estimated value P of the rotor angle.
Uvw phase current feed using {θ (n + 1)}
Back Iu fb, Iv fb is the current of the dq axis
It is converted into the feedback Id, Iq (step S6). d-
The q-axis current control unit 23 includes a dq-axis current feedback I
d, Iq, and q-axis current as output from the speed control unit 31
Command Iq dq axis voltage command so that ref matches
Perform dq axis current control calculation for calculating Vd 'and Vq'
(Step S7). The dq axis non-interference control unit 24 calculates
The d-q axis voltage command Vd ', which is the q-axis current control calculation result,
Vq 'and the average angular velocity M [P {ω (n)}]
And dq axis voltage command Vd ref, Vq total ref
Is calculated (step S8). dq axis → uvw phase converter 2
5 is the dq-axis voltage which is the result of the dq-axis non-interference control calculation
Command Vd ref, Vq ref from the three-phase voltage command Vu,
Vv and Vw are calculated (step S9). And PW
The M control unit 26 calculates the P value from the three-phase voltage commands Vu, Vv, Vw.
It outputs a WM signal to drive the power inverter device 2 and
Current control is realized by 180-degree sine wave of
S10). Thus, in the technology according to the present embodiment, the instantaneous
Estimated value of hourly angular velocity ω (n) P {ω (n)} and average angular velocity
M [P {ω (n)}], the estimated instantaneous error angle E
(N) is obtained, and the shadow of the estimated instantaneous error angle E (n) is obtained.
Hibiki is removed from rotor angle estimate P {θ (n + 1)}
Dq axes used for sensorless control
To further improve the accuracy of current and, consequently, control accuracy
Can be.

[0022]

As described above, according to the present invention,
By controlling the synchronous motor using the estimated rotor angle that does not include noise or error, it is possible to perform simple and highly accurate sensorless control of the synchronous motor with only two current sensors regardless of the presence or absence of salient poles. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a sensorless control device for a synchronous motor according to an embodiment of the present invention.

FIG. 2 is a hardware configuration diagram of the apparatus.

FIG. 3 is a flowchart showing a schematic operation in a sensorless routine of the present apparatus.

FIG. 4 is a flowchart showing a schematic operation in a startup routine of the apparatus.

FIG. 5 is a block diagram showing an overall configuration of a sensorless control device for a synchronous motor according to one embodiment of the present invention.

FIG. 6 is a flowchart showing a schematic operation in a sensorless routine of the sensorless control device for the synchronous motor according to the embodiment.

FIG. 7 is a conceptual diagram of a conventional control device for a synchronous motor with a sensor.

[Description of Signs] 1 ... 3-phase brushless DC motor (corresponding to synchronous motor) 2 ... Power inverter device 2 3 ... Power device 4 ... Inverter device 5 ... Current detection device 10 ... Angle estimation device (corresponding to rotor angle calculation means) 10 ': rotor angle calculation device (corresponding to rotor angle calculation means) 11: uvw phase → α─β axis conversion unit 12: speed electromotive force calculation unit 13: rotor angle calculation unit 14: estimated rotor angle calculation Unit (corresponding to a rotor angle estimating unit) 14 '... Rotor angle estimating unit (corresponding to a rotor angle estimating unit) 20 ... Power supply control device 21 ... Estimated speed calculating unit (corresponding to a rotor speed calculating unit) 21' ... Estimated angular speed calculation unit (corresponding to rotor speed calculation means) 22 ... uvw phase → dq axis conversion unit 23 ... dq axis current control unit 24 ... dq axis non-interference control unit (dq axis non-interference) 25 ... uvw phase → α─β Conversion unit 26 ... PWM control part 30 ... speed controller 31 ... speed control unit

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chika Manabe 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo F-term in Kobe Steel Research Institute, Kobe Research Institute 5H560 AA02 BB04 BB07 BB12 DC12 EB01 EC01 RR01 SS07 XA02 XA04 XA05 XA12 XA13 5H576 AA10 BB04 BB06 CC01 DD02 DD05 EE01 EE11 FF03 GG01 GG02 GG04 HA01 HB02 JJ03 KK05 LL22 LL46

Claims (12)

[Claims] 1. A rotor angle of a synchronous motor comprising a three-phase stator winding and a rotor having a permanent magnet is calculated based on two-phase detected current values and voltage command values, and the calculated angle is calculated. In the synchronous motor sensorless control method for controlling the synchronous motor using a rotor angle, an actual rotor angle of the synchronous motor is estimated based on the calculated rotor angle, and the estimated rotor angle is estimated. A sensorless control method for a synchronous motor, wherein the synchronous motor is controlled by using the method. 2. The calculated rotor angle and the calculated 2
2. The sensorless control method for a synchronous motor according to claim 1, wherein an actual rotor angle of the synchronous motor is estimated based on a detected current value of a phase. 3. In place of the two-phase detected current value,
3. The method according to claim 2, wherein a q-axis current feedback value based on a detected current value of the phase is used. 4. The method according to claim 1, wherein a rotor speed is calculated based on the estimated rotor angle, and the synchronous motor is controlled using the calculated rotor speed.
4. The sensorless control method for a synchronous motor according to claim 1. 5. Based on the calculated rotor speed, d
The sensorless control method for a synchronous motor according to any one of claims 1 to 4, wherein the voltage command value is generated by performing -q-axis non-interference control. 6. The sensorless control method for a synchronous motor according to claim 1, wherein the estimation is performed by the following equation. dθ ′ / dt = {θ ′ (Ta) −θ ′ (Tb)} / (T
a−Tb) θ (n) = θ (n−1) + dθ ′ / dt × T where dθ ′ / dt is the time differential value of the rotor angle, θ ′
(Ta) is the angle of the rotor at the time Ta, θ ′ (Tb) is the angle of the rotor at the time Tb, and θ (n) is the time n of the rotor.
, Θ (n−1) is the angle of the rotor at time n−1, and T is the sampling time. 7. The method according to claim 3, wherein the estimation is performed by the following equation. dθ ′ / dt = {θ ′ (Ta) −θ ′ (Tb)} / (T
a−Tb) θid = K × Id θ (n) = θ (n−1) + θid + dθ ′ / dt × T where dθ ′ / dt is the time differential value of the rotor angle, θ ′
(Ta) is the angle of the rotor at the time Ta, θ ′ (Tb) is the angle of the rotor at the time Tb, and θ (n) is the time n of the rotor.
, Θ (n−1) is the angle of the rotor at time n−1, T is the sampling time, θid is the correction amount of the rotor angle, K is the coefficient, and Id is the q-axis current feedback value. 8. Estimating an instantaneous angular velocity and an average angular velocity as an average thereof from the calculated rotor angle, and based on the estimated instantaneous angular velocity and average angular velocity, and the calculated rotor angle, 2. The method according to claim 1, wherein an actual rotor angle of the synchronous motor is estimated. 9. The rotor angle is estimated by the following equation.
A method for controlling a synchronous motor according to claim 8, wherein the sensorless control is performed. P {θ (n + 1)} = θ ′ (n) + K₁× M [P {ω (n)}] × T−K_Two× E (n) × T = θ ′ (n) −K_Two× P {ω (n)} × T + (K₁+ K_Two) × M [P {ω (n)}] × T where T is the sampling time, K₁, K_TwoAre each
0 <K₁<2,0 <K _Two<2, P 定 数 ω
(N)｝ is an estimated value of the instantaneous angular velocity ω (n).
[P {ω (n)}] is an estimated value of the instantaneous angular velocity ω (n).
, Where E (n) is the estimated instant at time n
Error angles, which are expressed as
You. P {ω (n)} = {θ ′ (n) −θ ′ (n−1)} / TM [P {ω (n)}] = LPF [P {ω (n)}] E (n) = P ｛ω (n)｝-M [P ｛ω (n)｝] where LPF is a cut-off frequency characteristic about the mechanical time constant
Represents a low-pass filter provided with. 10. A rotor angle calculating means for calculating a rotor angle based on a detected current value and a voltage command value of two phases of a synchronous motor including a three-phase stator winding and a rotor having a permanent magnet. A synchronous motor sensorless control device that controls the synchronous motor using the calculated rotor angle, wherein the rotor angle calculating means is configured to perform the operation based on the two-phase detected current value and voltage command value. A speed electromotive force calculating unit for calculating a speed electromotive force, a rotor angle calculating unit for calculating a rotor angle based on the calculated speed electromotive force,
A rotor angle estimator for estimating an actual rotor angle of the synchronous motor based on the calculated rotor angle, and controlling the synchronous motor using the estimated rotor angle. Characteristic sensorless control device for synchronous motor. 11. A rotor speed calculating means for calculating a rotor speed based on the estimated rotor angle, wherein the synchronous motor is controlled using the calculated rotor speed. The sensorless control device for a synchronous motor according to claim 10. 12. A dq-axis non-interference control means for performing dq-axis non-interference control based on the calculated rotor speed, and the dq-axis non-interference control is performed by performing the dq-axis non-interference control. The sensorless control device for a synchronous motor according to claim 11, wherein the command value is generated.