JP6102516B2 - Control method and control device for permanent magnet type synchronous motor - Google Patents

Description

  The present invention relates to a technique for calculating a magnetic pole position of a rotor of a permanent magnet type synchronous motor.

  As a technique for reducing the price of a control device for a permanent magnet type synchronous motor (hereinafter also referred to as PMSM), so-called sensorless control that operates without using a magnetic pole position detector of a rotor has been put into practical use. Sensorless control is to realize torque control and speed control of a synchronous motor by calculating the rotor speed and magnetic pole position from the terminal voltage and current information of the synchronous motor and performing current control based on these. .

  For example, in the sensorless control technology described in Patent Document 1 and Non-Patent Document 1, an extended induced voltage generated in a direction orthogonal to the magnetic pole direction of the rotor is calculated, and the magnetic flux estimated in the control is calculated from the calculated value. A position calculation error (magnetic pole position error or axis deviation) between the axis and the actual magnetic flux axis is detected, and the magnetic pole position and speed are calculated from this position calculation error.

  Patent Document 2 discloses, as a technique for reducing the price of a control device for a three-phase PWM inverter that controls the terminal voltage of an AC motor, a current detection device that detects a current flowing through the lower arm of each phase of the inverter using a shunt resistor. Is disclosed. In this prior art, the phase current of the inverter is detected from the current detection value by the shunt resistance when the lower arm of the inverter is turned on, and compared with the case where a relatively expensive current detection element such as a Hall element is used. It is possible to reduce the price and size.

Japanese Patent No. 3411878 (paragraphs [0058] to [0083], FIG. 1, FIG. 4, etc.) JP-A-63-80774 (page 2, lower left column, line 13 to page 4, upper left column, line 15, FIG. 1, FIG. 2, etc.)

Takahashi Aihara, Akio Toba, Takao Yanase, Akihide Mashimo, and Kenji Endo, `` Sensorless Torque Control of Salient-Pole Synchronous Motor at Zero-Speed Operation '', IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL.14, NO.1, JANUARY 1999

The current detection device described in Patent Document 2 can detect the phase current of two or more of the three phases and detect the d-axis current and the q-axis current which are the orthogonal rotation coordinate components of each phase of the inverter. Is a timing at which the lower arm of at least two phases is turned on. However, depending on the condition of the output voltage of the inverter, there is no timing for temporarily turning on the lower arm of two or more phases, and in this case, the d-axis current and the q-axis current cannot be detected.
On the other hand, in Patent Document 1, for example, as shown in Equations 9 to 13 in paragraphs [0059] to [0068], a differential operation of the q-axis current converted from the phase current is necessary to calculate the expansion induced voltage. In addition, in order to obtain the position calculation error, differential calculation of the d-axis current and the q-axis current is necessary.

For this reason, even if it is going to implement | achieve sensorless control of patent document 1 etc. using the comparatively cheap electric current detection apparatus described in patent document 2, at the timing which cannot detect d-axis current and q-axis current, expansion induced voltage As a result, the position calculation error cannot be calculated.
Further, in order to calculate the differential current value in order to calculate the extended induced voltage in Patent Document 1, etc., it is necessary to calculate the current difference between the sample points. Therefore, when the phase current cannot be detected, it becomes impossible to perform a current difference calculation in the next sampling period. In this case, it is possible to use the current differential value based on the previous difference calculation value, but there is a possibility that the extended induced voltage calculation value includes an error, and as a result, the speed calculation value and the position calculation value include an error. There was a problem of becoming.

In paragraphs [0077] and [0078] of Patent Document 1, the d-axis in the calculation formula for obtaining the position calculation error is based on the assumption that the change in the motor current is small if the speed and load of the motor are constant. It has been suggested to ignore the differential terms of the current and q-axis current.
However, assuming that the speed and load of the motor are constant is lacking in generality, and when the speed of the motor changes, there is a problem that the detection accuracy of the speed and the magnetic pole position is lowered as a result.

Accordingly, an object of the present invention is to accurately calculate the rotor magnetic pole position calculation error and detect the motor speed and magnetic pole position with high accuracy even in a situation where the motor current cannot be detected at a plurality of consecutive sample points. Another object of the present invention is to provide a method for controlling a permanent magnet type synchronous motor.
Another object of the present invention is to provide a low-cost and small-sized control device for realizing the above control method.

  In order to solve the above-mentioned problem, a control method for a permanent magnet type synchronous motor according to the present invention includes an electric motor between a current first sample point and a past second sample point. If there is a sample point where the current cannot be detected and the motor current can be detected at the first and second sample points, the first and second motor current detection values at the first and second sample points, 1, a first sample based on the time interval between the second sample points, the average value of the terminal voltage equivalent value such as the voltage command value of the motor in the time interval, and the previous value of the speed calculation value of the motor The position calculation error at the point is obtained, and the previous value of the position calculation error is held for the sample point where the motor current cannot be detected. In addition, the speed and magnetic pole position of the motor are calculated from the position calculation error thus obtained, and sensorless control of the motor is performed by the power converter using these speed calculation value and position calculation value.

  As described in claim 2, in obtaining the position calculation error at the first sample point, the first and second motor current detection values and the time interval between the first and second sample points Based on the average value of the terminal voltage equivalent value of the motor in the time interval and the speed calculation value of the motor, the expansion induced voltage in the direction orthogonal to the magnetic pole direction of the rotor is calculated, and this expanded induced voltage is configured. The position calculation error may be obtained from the orthogonal voltage component.

  According to a third and fourth aspect of the invention, the current of the lower arm of each phase of the inverter that drives the motor is detected by a shunt resistor, and the phase current of the motor calculated from this detected current value and the modulation factor of the inverter. Is preferably used as the motor current detection value.

According to a fifth aspect of the present invention, there is provided a control apparatus for a permanent magnet type synchronous motor, wherein a current detection unit that detects a current of the motor, a voltage generation unit that generates a terminal voltage equivalent value of the motor, and a rotor A position calculation error estimating unit that estimates a magnetic pole position calculation error; and a speed / position calculation unit that calculates the motor speed and the magnetic pole position from the position calculation error.
Then, the position calculation error estimation unit detects at the first and second sample points when there is a sample point at which the motor current cannot be detected between the current first sample point and the past second sample point. The first and second motor current detection values, the time interval between the first and second sample points, the average value of the terminal voltage equivalent value generated by the voltage generator in the time interval, and the motor speed calculation The position calculation error at the first sample point is obtained based on the previous value of the value. For the sample points where the motor current cannot be detected, the previous value of the position calculation error is held.

  According to a sixth aspect of the present invention, the position calculation error estimation unit includes the first and second motor current detection values, the time interval between the first and second sample points, and the terminal voltage equivalent value of the motor. An extended induced voltage calculation unit that calculates an extended induced voltage based on an average value in a time interval and a motor speed calculation value, and an angle difference calculation unit that obtains a position calculation error from orthogonal voltage components that constitute the extended induced voltage It is desirable to provide

According to a seventh and eighth aspect of the present invention, a current detection unit comprising a shunt resistor for detecting the current of the lower arm of each phase of the inverter that drives the motor, a current detection value by the shunt resistor, and a modulation rate of the inverter And a phase current calculation unit for calculating the phase current of the motor from the above, and the phase current may be used as the motor current detection value.
In the control device of the present invention, as described in claim 9, the current detection unit, the voltage generation unit, the position calculation error estimation unit, and the speed / position calculation unit are integrated with the inverter and the drive signal generation unit thereof. Therefore, it is desirable to configure as a single device.

According to the present invention, even if the current of the permanent magnet type synchronous motor becomes temporarily undetectable, if the motor current can be detected at the current sample point and the past sample point across this undetectable period, these motors The position error of the rotor magnetic pole can be detected based on the current detection value, the average value of the terminal voltage equivalent values, and the like. Therefore, it is possible to calculate the speed and magnetic pole position of the motor using this position calculation error, and to perform sensorless control of the motor with high accuracy.
Furthermore, by detecting the motor current using a shunt resistor, it is possible to reduce the price and size of the control device.

It is a block diagram which shows the structure of the drive system of PMSM. It is explanatory drawing of d and q axis orthogonal rotation coordinate and (gamma) and (delta) axis orthogonal rotation coordinate. It is a circuit diagram which shows the structure of the inverter in FIG. It is a timing chart of (gamma) and (delta) axis | shaft expansion induced voltage calculation in embodiment of this invention. It is a flowchart which shows operation | movement of embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a drive system for a permanent magnet type synchronous motor.
In FIG. 1, 50 is a three-phase AC power source, 60 is a rectifier circuit that rectifies a three-phase AC voltage and outputs a DC voltage, and 70 converts the DC voltage into a three-phase AC voltage having a predetermined magnitude and frequency. An inverter 80 is a permanent magnet type synchronous motor (PMSM).

  The inverter 70 can realize highly accurate torque control and speed control of the PMSM 80 by performing control on the d and q axis orthogonal rotation coordinates synchronized with the rotation of the rotor of the PMSM 80. Here, with respect to the d and q axes, the N pole direction of the magnetic pole of the rotor is defined as the d axis, and the 90 ° advance direction from the d axis is defined as the q axis. However, in the case of sensorless control that operates without using the magnetic pole position detector, the positions of the d and q axes cannot be directly detected. Therefore, in the PMSM 80 control device, the control calculation is performed using the voltage and current replaced on the γ and δ axes, which are the estimated axes of the d and q axes.

FIG. 2 is an explanatory diagram of d, q axis orthogonal rotation coordinates and γ, δ axis orthogonal rotation coordinates.
In FIG. 2, θ _err is the γ-axis angle (position calculation value) θ ₁ with respect to the u-phase winding of PMSM80 and the d-axis angle (actual magnetic pole position) θ _r with respect to the u-phase winding. And is defined by Equation (1).
[Equation 1]
θ _err = θ ₁ −θ _r
Further, as shown in FIG. 2, d, the angular velocity of the q-axis (the rotor speed) and omega _r, gamma, the angular velocity of the δ-axis (speed operation value) and omega _1.

Next, the speed control method, current control method, and voltage control method of PMSM 80 in FIG. 1 will be described together with the configuration and operation of the control device.
1 (parts other than the three-phase AC power supply 50, the rectifier circuit 60, the inverter 70, and the PMSM 80) is mainly configured by an arithmetic device and an arithmetic program such as a microcomputer, and is realized only by hardware. Is not to be done.

The subtracter 16 in FIG. 1 calculates the deviation between the speed command value ω _r ^* and the speed calculation value ω ₁ . The speed regulator 17 performs a calculation to make the deviation zero, and generates a torque command value τ ^* . The current command calculator 18 calculates the γ-axis current command value i _γ ^* and the δ-axis current command value i _δ ^* so as to generate torque according to the torque command value τ ^* .

The subtractor 19a calculates a deviation between the γ-axis current command value i _γ ^* and the γ-axis current detection value i _γdet, and the subtractor 19b calculates the δ-axis current command value i _δ ^* and the δ-axis current detection value i _δdet . Calculate the deviation.
The γ-axis current adjuster 20a generates a γ-axis voltage command value v _γ ^* by performing an operation that makes the deviation output from the subtractor 19a zero. The δ-axis current adjuster 20b performs a calculation to make the deviation output from the subtractor 19b zero, and generates a δ-axis voltage command value v _δ ^* . These γ-axis voltage command value v _γ ^* and δ-axis voltage command value v _δ ^* are input to the coordinate converter 15.
Here, the γ-axis current regulator 20a and the δ-axis current regulator 20b constitute a voltage generator in the claims.

The coordinate converter 15 converts the γ-axis voltage command value v _γ ^* and the δ-axis voltage command value v _δ ^* into a three-phase voltage command value v _u ^* , based on the position calculation value θ ₁ calculated by the integrator 34. The coordinates are converted into v _v ^* and v _w ^* , and these voltage command values v _u ^* , v _v ^* and v _w ^* are input to the modulation factor calculator 21. The modulation factor calculator 21 also receives the DC voltage detection value E _dc detected by the voltage detection circuit 12.
The modulation factor calculator 21 calculates the modulation factor command values λ _u ^* , λ _v ^* , λ _w ^* from the voltage command values v _u ^* , v _v ^* , v _w ^* and the DC voltage detection value E _{dc according} to Equation 2 below ^. Is calculated.

The PWM circuit 13 as the drive signal generation unit converts each phase output voltage of the inverter 70 from the modulation rate command values λ _u ^* , λ _v ^* , λ _w ^* to voltage command values v _u ^* , v _v ^* , v _{w, respectively.} ^* Generates a gate signal for control. The inverter 70 controls the terminal voltage of the PMSM 80 to the voltage command values v _u ^* , v _v ^* , and v _w ^* by controlling on / off of the internal semiconductor switching element based on the gate signal.
In this specification, γ, δ-axis voltage command values v _γ ^* , v _δ ^* , γ, δ-axis voltage detection values v _γdet , v _δdet , three-phase voltage command values v _u ^* , v _v ^* , v _w ^* and the terminal voltage itself of PMSM80 are collectively referred to as a terminal voltage equivalent value of PMSM80.
In the drive system shown in FIG. 1, the rotor speed ω _r of the PMSM 80 is controlled according to the speed command value ω _r ^* by the above-described action.

Next, FIG. 3 is a circuit diagram showing a configuration of the inverter 70.
In FIG. 3, P and N are DC terminals, u, v and w are AC terminals, 71 to 73 are upper arm main circuit elements made of IGBT, 74 to 76 are lower arm main circuit elements, and 77 is a capacitor. . Reference numerals 78u, 78v, and 78w denote shunt resistors connected in series to the lower arm main circuit elements 74 to 76, respectively.
Shunt resistors 78u, 78V, 78w are provided for detecting the lower arm current of each phase of the inverter 70, the lower arm current detection value _{i un, i vn, i wn} is the lower arm main circuit elements 74 to 76 It corresponds to each phase current of PMSM80 when is turned on.

The phase current calculator 11 in FIG. 1 determines the on / off states of the lower arm main circuit elements 74 to 76 of the inverter 70 from the modulation factor command values λ _u ^* , λ _v ^* , λ _w ^* .
When two or more of the lower arm main circuit elements 74 to 76 are turned on, the phase current detection values i _udet , i _vdet , i _wdet are _obtained from the lower arm current detection values i _un , i _vn , i _wn. Obtained and output to the coordinate converter 14. On the other hand, when two or more of the lower arm main circuit elements 74 to 76 are not turned on, it is determined that the phase current cannot be detected, and the phase current detection values i _udet , i _vdet , i _wdet are the previous values. Hold it.

The coordinate converter 14 converts the phase current detection values i _udet , i _vdet , i _wdet into the γ-axis current detection value i _γdet and the δ-axis current detection value i _δdet based on the position calculation value θ ₁ calculated by the integrator 34. Convert coordinates to. When two or more of the lower arm main circuit elements 74 to 76 are not turned on, the phase current detection is impossible, and the phase current detection values i _udet , i _vdet , i _wdet are held at the previous values. The γ-axis current detection value i _γdet and the δ-axis current detection value i _δdet are also maintained as the previous values.

Next, speed calculation / magnetic pole position calculation of the PMSM 80 will be described. First, the operation of the extended induced voltage calculator 31 in FIG. 1 will be described.
When the phase current detection values i _udet , i _vdet , i _wdet can always be detected for each current detection period (sample point), based on the PMSM discrete voltage equation in the interval from the sample point (n−1) to (n) Γ, δ-axis expansion induced voltage calculation values E _{exγest (n)} and E _{exδest (n)} at the sample point (n) are obtained by Equation 3.

Γ and δ-axis voltage detection values v _γdet and v _δdet in Equation 3 are terminal voltage equivalent values, and γ and δ-axis voltages calculated by the γ-axis current regulator 20a and the δ-axis current regulator 20b as voltage generators. The command values v _γ ^* and v _δ ^* are used. Here, γ, δ-axis voltage detection values v _{γdet (n)} and v _{δdet (n)} at the sample point (n) are set to γ, δ at the sample point (n−1) in consideration of the control delay of the inverter 70. The δ-axis voltage command values v _γ ^* _(n−1) and v _δ ^* _(n−1) are used.
Although detailed description is omitted, the output voltage of the inverter 70 detected by a voltage detector (not shown) as a voltage generation unit is used instead of the γ and δ-axis voltage detection values v _γdet and v _δdet. Also good.

On the other hand, phase current detection values i _udet , i _vdet , i _wdet are obtained at sample points (n−m) and (n) separated in time, and sample points (n−m + 1) sandwiched between these sample points When the phase current detection values i _udet , i _vdet , i _wdet are not obtained in the section of (n−1), that is, the phase current is detected at two non-continuous sample points (n−m), (n) When the values i _udet , i _vdet , and i _wdet are obtained, the γ and δ axes at the sample point (n) are based on the voltage equation of the PMSM discrete system in the section from the sample point (nm) to (n). The extended induced voltage calculation values E _{exγest (n)} and E _{exδest (n)} are obtained by Equation 4.

  FIG. 4 shows a timing chart of the γ and δ axis expansion induced voltage calculation at this time. FIG. 4 shows the case where m = 3 in Equation 4. Also, for each sample point shown in FIG. 4, in order to distinguish it from the subscript (n) of the sample point in the general formulas 3 and 4, the sample point is (N-4),. ), (N + 1). In the example of FIG. 4, the sample point (N) corresponds to the first sample point in the claims, and the sample point (N-3) corresponds to the second sample point in the claims.

As is apparent from FIG. 4, the γ and δ-axis voltage detection values v _{γdet (n)} and v _{δdet (n ) at} all sample points (n) (n = (N + 1) to (N−4) in FIG. 4). ₎ Are the γ and δ-axis voltage command values v _γ ^* _(n−1) and v _δ ^* _{(n−1) at the} previous sample point (n−1).
Further, in the sample point (N) at which the phase current can be detected, v _{γdetAVE (n)} and v _{δdetAVE (n)} in Equation 4 are γ of the three sample points (N-3) to (N-1). , Δ-axis voltage detection values v _{γdet (n)} , v _{δdet (n} ) are average values in the time interval (3T _s ).

Therefore, the γ and δ-axis expansion induced voltages E _{exγest (N)} and E _{exδest (N)} at the sample point (N) are average values v _{γdetAVE (N)} of the γ and δ-axis voltage detection values at the sample point (N). , V _{δdetAVE (N)} and γ, δ-axis current detection values i _{γdet (N-3)} , i _{δdet (N-3)} , i _{γdet (N)} , i at sample points (N-3), (N) _{Using δdet (N)} , the speed calculation value ω _{1 (N−1),} and the motor constants R _a , L _d , and L _q , it can be obtained by the above-described Expression 4.
The speed calculation value ω _{1 (N−1)} is the speed calculation value of the previous sample point (N−1) where the phase current could not be detected, and is held from the sample point (N−3) as described below. The speed calculation value ω _{1 (N−1)} may be obtained by using the γ and δ axis expansion induced voltage calculation values E _{exγest (N−3)} and E _{exδest (N−3)} that are being continued.

For sample points where the phase current detection values i _udet , i _vdet , i _wdet cannot be obtained, such as the sample points (N-2) and (N-1) including the sample point (N-1), γ , Δ-axis expansion induced voltage calculation values E _{exγest (n)} and E _{exδest (n) hold the} previous values E _{exγest (n−1)} and E _{exδest (n−1)} .
The speed calculation value ω ₁ and the position calculation value θ ₁ can be obtained by calculation described later using the γ and δ-axis expansion induced voltage calculation values E _exγest and E _exδest obtained by Expression 3 or 4.

If m = 1 in Equation 4, Equation 4 is equal to Equation 3. For this reason, the γ and δ-axis expansion induced voltage calculation values when the phase current detection value is always obtained for each sampling point may be set to m = 1 in Equation 4.
That is, when the control device has a program for executing Equation 4, and when m = 3 is set, for example, a sample when the phase current detection value is obtained at discontinuous sample points (n−3) and (n) Γ and δ-axis expansion induced voltage calculation at the point (n) can be performed. When m = 1 is set, γ and δ-axis expansion induced voltage calculation is performed at the sample point (n) when the phase current detection value is obtained at the continuous sample points (n−1) and (n). be able to. That is, since it is sufficient for the control device to change the value of m in Equation 4, it is not necessary to provide a program for executing Equation 3.

As described above, according to the calculation of Equation 4, the phase current detection values i _udet , i _vdet , i _wdet are temporarily obtained as the sample points (N−2) and (N−1) in FIG. 4. Even when this is not possible, the γ and δ-axis expansion induced voltage calculation values at the sample point (N) can be accurately obtained. For sample points (N-2) and (N-1), the γ and δ-axis expansion induced voltage calculation values at the sample point (N-3) where the phase current was detectable last time are retained and used. be able to.

Next, a method for calculating the speed and magnetic pole position of the PMSM ₈₀ using the γ and δ axis expansion induced voltage calculation values E _exγest and E _exδest will be described.
Angle difference calculator 32 of FIG. 1, gamma, [delta] axis extended induced voltage calculation value _{E exγest,} the position calculation error (estimation _value) θ errest from _{E Exderutaest} computed by Equation 5.

積分器３４は、速度演算値ω_１を積分して位置演算値θ_１を算出する。ここで、速度演算器３３及び積分器３４は、速度・位置演算部３５を構成している。
以上の演算により、位置演算誤差θ_ｅｒｒが零になるように速度演算値ω_１及び位置演算値θ_１を真値に収束させ、ＰＭＳＭ８０のトルク制御、速度制御を高精度に行うことが可能になる。 Here, the angle difference calculator 32 and the extended induced voltage calculator 31 constitute a position calculation error estimator 30.
The speed calculator 33 performs the calculation of Formula 6 using the position calculation error θ _errest calculated by Formula 5 to determine the speed calculation value ω ₁ . In Equation 6, K _P is a proportional gain, and T _I is an integration time. The speed calculation value ω ₁ obtained in this way is input to the subtractor 16 and the integrator 34, and also input to the extended induced voltage calculator 31 for performing the calculation of Expression 4.

The integrator 34 integrates the speed calculation value ω ₁ to calculate the position calculation value θ ₁ . Here, the speed calculator 33 and the integrator 34 constitute a speed / position calculator 35.
With the above calculation, the speed calculation value ω ₁ and the position calculation value θ ₁ are converged to true values so that the position calculation error θ _err becomes zero, and the torque control and speed control of the PMSM 80 can be performed with high accuracy. Become.

FIG. 5 is a flowchart showing the operation of this embodiment.
In FIG. 5, when the phase current is detected at the current sample point (n) (step S1 YES), it is determined whether or not the phase current is also detected at the previous sample point (n−1). If the phase current is also detected at the previous sample point (n−1) (YES in step S2), the calculation of Equation 3 and Equation 5 is sequentially performed to calculate the speed calculation value ω ₁ and the position calculation value θ _1. And sensorless control is performed (steps S3 to S6).

Further, when the phase current is not detected at the current sample point (n) and the previous values of the γ and δ axis expansion induced voltages are held (step S1 NO, step S7 YES), the previous values are used. Then, the processes after step S4 are executed. If the previous value of the γ, δ-axis expansion induced voltage is not held (NO in step S7), the process is terminated as it is.
In step S2, if no phase current was detected at the previous sample point (n-1) (NO in step S2), whether or not the phase current was detected at the previous sample point (nm). to decide. When the phase current is detected at the sample point (nm) (step S8 YES), the γ and δ-axis expansion induced voltage is calculated by the equation 4 (step S9), and then the processing after step S4 is executed. To do.

  If no phase current is detected at the sample point (nm) (NO in step S8), the process is terminated as it is. In this case, it may be possible to apply Equation 4 by sequentially incrementing m and going back to the sample point where the phase current is detected. Alternatively, if there is no past sample point (nm) in which the phase current is detected even if m is increased to the upper limit value, if a certain amount of calculation error can be tolerated, γ, δ in Equation 4 can be used. Equation 4 may be applied by approximating the second term in the right parenthesis in each arithmetic expression of the axial expansion induced voltage to zero.

  INDUSTRIAL APPLICABILITY The present invention can be used as a control method and control device for PMSM, which is a drive source for fans / blowers, pumps, air conditioners, various transport machines and the like.

11: Phase current calculator 12: Voltage detection circuit 13: PWM circuit 14, 15: Coordinate converters 16, 19a, 19b: Subtractor 17: Speed controller 18: Current command calculator 20a: γ-axis current controller 20b: δ-axis current regulator 30: position calculation error estimator 31: extended induced voltage calculator 32: angle difference calculator 33: speed calculator 34: integrator 35: speed / position calculator 50: three-phase AC power supply 60: rectification Circuit 70: Inverters 71-73: Upper arm main circuit elements 74-76: Lower arm main circuit elements 77: Capacitors 78u, 78v, 78w: Shunt resistors 80: Permanent magnet synchronous motor (PMSM)

Claims (9)

A control method for controlling a permanent magnet type synchronous motor having no rotor magnetic pole position detector by means of a power converter, wherein the position of the magnetic pole of the rotor is determined by using the terminal voltage equivalent value of the motor and the current of the motor. In the control method of the permanent magnet type synchronous motor, which calculates a calculation error and detects the speed and magnetic pole position of the motor from the position calculation error,
When there is a sample point where the current of the motor cannot be detected between the current first sample point and the past second sample point, and the current of the motor can be detected at the first and second sample points Are the first and second motor current detection values at the first and second sample points, the time interval between the first and second sample points, and the time interval of the terminal voltage equivalent value of the motor. The position calculation error at the first sample point is obtained based on the average value at and the previous value of the speed calculation value of the motor,
A control method for a permanent magnet type synchronous motor, wherein a previous value of the position calculation error is held for a sample point where the current of the motor cannot be detected. In the control method of the permanent magnet type synchronous motor according to claim 1,
Using the information for obtaining the position calculation error at the first sample point, an extended induced voltage in a direction orthogonal to the magnetic pole direction of the rotor is calculated, and the position is determined from the orthogonal voltage component constituting the extended induced voltage. A control method for a permanent magnet type synchronous motor, characterized in that a calculation error is obtained. In the control method of the permanent magnet type synchronous motor according to claim 1 or 2,
The current of the lower arm of each phase of the inverter as the power converter is detected, and the phase current of the motor calculated from the current detection value and the modulation factor of the inverter is used as the motor current detection value. To control a permanent magnet type synchronous motor. In the control method of the permanent magnet type synchronous motor according to claim 3,
A control method of a permanent magnet type synchronous motor, wherein the current of the lower arm is detected by a shunt resistance. A control device for controlling a permanent magnet type synchronous motor having no rotor magnetic pole position detector by means of a power converter, wherein the position of the magnetic pole of the rotor is determined by using the terminal voltage equivalent value of the motor and the current of the motor. In a control device for a permanent magnet type synchronous motor that calculates a calculation error and detects the speed and magnetic pole position of the motor from the position calculation error,
A current detection unit for detecting a current of the motor, a voltage generation unit for generating the terminal voltage equivalent value, a position calculation error estimation unit for estimating the position calculation error, and the speed and magnetic pole of the motor from the position calculation error A speed / position calculation unit for calculating the position,
The position calculation error estimator is
When there is a sample point where the current of the motor cannot be detected between the current first sample point and the past second sample point, the current detection unit detects the sample point at the first and second sample points. The first and second motor current detection values, the time interval between the first and second sample points, the average value of the terminal voltage equivalent value generated by the voltage generator in the time interval, and the motor The position calculation error at the first sample point based on the previous value of the speed calculation value of
A control device for a permanent magnet type synchronous motor, wherein a previous value of the position calculation error is held for a sample point where the current of the motor cannot be detected. In the control device for the permanent magnet type synchronous motor according to claim 5,
The position calculation error estimator is
An extended induced voltage calculation unit that calculates an extended induced voltage in a direction orthogonal to the magnetic pole direction of the rotor using information for obtaining the position calculation error at the first sample point, and the extended induced voltage An angle difference calculation unit for obtaining the position calculation error from the orthogonal voltage component;
A control device for a permanent magnet type synchronous motor. In the control device for a permanent magnet type synchronous motor according to claim 5 or 6,
A current detection unit for detecting a current of a lower arm of each phase of the inverter as the power converter; a phase current calculation for calculating a phase current of the electric motor from a current detection value by the current detection value and a modulation factor of the inverter And comprising
A control apparatus for a permanent magnet type synchronous motor, wherein the phase current is used as the motor current detection value. In the control device for the permanent magnet type synchronous motor according to claim 7,
A control device for a permanent magnet type synchronous motor, wherein the current detection unit is constituted by a shunt resistor. In the control device for the permanent magnet type synchronous motor according to claim 7,
A control apparatus for a permanent magnet type synchronous motor, wherein the current detection unit, the voltage generation unit, the position calculation error estimation unit, and the speed / position calculation unit are integrated with the inverter and a drive signal generation unit thereof. .

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