JP2015122928A - Motor controller and generator controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the reduction in accuracy of control accompanied with fluctuation of a motor parameter.SOLUTION: A motor controller 3 applies a voltage vector to a three-phase motor 1 by using an inverter 2 so that the armature interlinkage magnetic flux of the three-phase motor 1 and a motor torque follow the command magnetic flux and command torque, respectively. The motor controller 3 includes: a magnetic flux estimation part 23 for estimating the armature interlinkage magnetic flux; and a command magnetic flux specification part for correcting the command magnetic flux by executing feedback control using (a) a first inner product between the estimated armature interlinkage magnetic flux and a motor current flowing through the three-phase motor 1 or (b) a second inner product between the estimated magnet magnetic flux of a permanent magnet 1 m of the three-phase motor 1 and the motor current.

Description

  The present invention relates to a motor control device and a generator control device.

Conventionally, direct torque control (DTC) has been proposed as a control method for a three-phase motor. In an example of direct torque control, a three-phase current i is detected. The three-phase current i is converted into the two-phase current i _αβ . From the two-phase current i _αβ and the command two-phase voltage v _αβ ^* , using the equations (A-1) to (A-4), the armature linkage flux of the three-phase motor and the armature linkage flux The phase and motor torque are estimated. That is, the estimated magnetic flux [psi _{.alpha..beta,} the estimated magnetic flux [psi _.alpha..beta phase theta _S, is determined and the estimated torque T. The alpha axial estimated magnetic flux [psi _alpha, an alpha-axis component of the estimated magnetic flux [psi _{.alpha..beta.} The beta axis estimated magnetic flux [psi _beta, is a beta-axis component of the estimated magnetic flux [psi _{.alpha..beta.} The α-axis current i _α is an α-axis component of the two-phase current i _αβ . The β-axis current i _β is a β-axis component of the two-phase current i _αβ . The command α-axis voltage v _α ^* is an α-axis component of the command two-phase voltage v _αβ ^* . The command β-axis voltage v _β ^* is a β-axis component of the command two-phase voltage v _αβ ^* . _ψ α _{| t = 0} is the value of [psi _alpha at time t = 0 (initial value of [psi _{alpha). ψ} β _{| t = 0} is the value of [psi _beta at time t = 0 ([psi initial value of _beta). R _a is a resistance value per phase of the armature winding of the three-phase motor. P _n is the number of pole pairs of the motor.

Next, an error (torque error ΔT = T ^* −T) between the estimated torque T and the command torque T ^* is obtained. From the torque error ΔT, the phase θ _S, and the target value (command magnetic flux) | ψ _S ^* | of the amplitude of the armature linkage flux, the command flux vector ψ _αβ ^{* of the} armature linkage flux is obtained. The command magnetic flux | ψ _S ^* | is specified according to the command torque T ^* using table data representing the relationship between the command magnetic flux | ψ _S ^* | and the command torque T ^* . Table data is prepared in advance.

The command two-phase voltage v _αβ ^* is obtained using equations (A-5) and (A-6) so that the estimated magnetic flux _ψαβ matches the command magnetic flux vector _ψαβ ^* . [psi _alpha ^* is a command flux vector [psi _.alpha..beta ^* of alpha axis component. [psi _beta ^* is a command flux vector [psi _.alpha..beta ^* of beta axis component.

The command two-phase voltage v _αβ ^* is converted into the command three-phase voltage v _uvw ^* (v _u ^* , v _v ^* and v _w ^* ). A voltage vector corresponding to the command three-phase voltage v _uvw ^* is generated by the inverter. This voltage vector is applied to the three-phase motor.

  In the motor control system described above, the command magnetic flux vector is specified using a command magnetic flux calculator (RFVC: Reference Flux Vector Calculator). For this reason, the above motor control method can be referred to as RFVC DTC (Reference Flux Vector Calculation Direct Torque Control).

  Patent Document 1 and Non-Patent Document 1 describe examples of motor control devices using direct torque control.

JP 2009-33876 A

Inoue and three others, “Torque ripple reduction, and flux-weakening control for interior permanent magnet synchronous motor based on direct torque control”, 2006 Proceedings of the IEEJ National Conference, IEEJ, March 2006, 4th volume, 4-106, p. 166

  The inventors of the present invention have studied to suppress a decrease in control accuracy associated with fluctuations in motor parameters (such as magnetic flux generated by a permanent magnet).

That is, this disclosure
A motor control device that applies a voltage vector to the three-phase motor using an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux and the command torque, respectively.
A magnetic flux estimator for estimating the armature flux linkage;
(A) a first inner product of the estimated armature flux linkage and a motor current flowing through the three-phase motor, or (b) an estimated magnet flux of the permanent magnet of the three-phase motor and the motor current. A command magnetic flux specifying unit that corrects the command magnetic flux by executing feedback control using the second inner product of
A motor control device comprising:

  According to the above technique, the command magnetic flux is appropriately corrected. Therefore, it is possible to suppress an increase in motor current or power loss due to motor parameter fluctuations, motor current detection errors, and the like.

Block diagram of three-phase motor, inverter and motor control device Diagram for explaining the dq coordinate system Diagram for explaining αβ coordinate system 1 is a block diagram of a motor control device according to a first embodiment. Block diagram for explaining how to specify command magnetic flux vector Block diagram for explaining the internal configuration of the magnetic flux amplitude command correction amount calculation unit Another block diagram for explaining the internal configuration of the magnetic flux amplitude command correction amount calculation unit Yet another block diagram for explaining the internal configuration of the magnetic flux amplitude command correction amount calculation unit The figure for demonstrating the magnetic flux vector and electric current vector at the time of using the conventional motor control apparatus The figure for demonstrating the relationship between the parameter error of magnet magnetic flux and the electric current at the time of using the conventional motor control apparatus The figure for demonstrating the magnetic flux vector and electric current vector in 1st Embodiment The figure which shows the experimental result for confirming the effect of 1st Embodiment The block diagram of the motor control apparatus which concerns on the modification of 1st Embodiment. Block diagram of a motor control device according to the second embodiment Block diagram for explaining the internal configuration of the magnetic flux amplitude command correction amount calculation unit The figure for demonstrating the effect of 2nd Embodiment Block diagram of a motor control device according to the third embodiment Block diagram for explaining the internal configuration of the magnetic flux amplitude command correction amount calculation unit Block diagram of a generator control device according to a fourth embodiment

The first aspect of the present disclosure is:
A motor control device that applies a voltage vector to the three-phase motor using an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux and the command torque, respectively.
A magnetic flux estimator for estimating the armature flux linkage;
(A) a first inner product of the estimated armature flux linkage and a motor current flowing through the three-phase motor, or (b) an estimated magnet flux of the permanent magnet of the three-phase motor and the motor current. A command magnetic flux specifying unit that corrects the command magnetic flux by executing feedback control using the second inner product of
A motor control device comprising:

  The first inner product and the second inner product in the first aspect are effective indexes for correcting the command magnetic flux. The motor control device according to the first aspect corrects the command magnetic flux using the first inner product or the second inner product. Therefore, even if a motor parameter fluctuates due to a temperature rise or a motor current detection error occurs, an increase in motor current or power loss associated therewith is suppressed.

The second aspect of the present disclosure includes, in addition to the first aspect,
The command magnetic flux specifying unit is
(J) The deviation between the first inner product and the reference value specified from the inductance of the three-phase motor and the motor current approaches zero.
(K) The deviation between the first inner product and the reference value specified from the command torque approaches zero.
(L) The deviation between the second inner product and the given reference value approaches zero, or
(M) The deviation between the first inner product or the second inner product and the reference value specified from the deviation between the limit voltage for the magnetic flux weakening control and the amplitude of the command voltage representing the voltage vector is close to zero. A motor control device that performs the feedback control is provided.

  According to (j), the command magnetic flux is corrected according to the motor current. According to (k), the command magnetic flux is corrected according to the torque. According to (l), the command magnetic flux is easily corrected. According to (m), the command magnetic flux is corrected so as to be adapted to the flux-weakening control.

The third aspect of the present disclosure includes, in addition to the second aspect,
The command magnetic flux specifying unit is
(J) The deviation between the first inner product and the product of the inductance of the three-phase motor and the square of the amplitude of the motor current approaches zero.
(K) The deviation between the first inner product and the product of the constant and the square of the command torque approaches zero.
(L) the second inner product approaches zero, or
(M) The deviation between the first inner product or the second inner product and the output of the second feedback control that receives the deviation between the limit voltage for the flux-weakening control and the amplitude of the command voltage representing the voltage vector is zero. A motor control device that executes the feedback control is provided.

  According to (J) to (L), maximum torque / current (MTPA: Maximum Torque Per Ampere) control can be executed with high accuracy. According to (M), the flux-weakening control can be executed with high accuracy.

The fourth aspect of the present disclosure is in addition to any one of the first to third aspects,
The command magnetic flux specifying unit has an inductance value of the three-phase motor as a d-axis inductance value, a value larger than the d-axis inductance and smaller than the q-axis inductance, or smaller than the d-axis inductance and larger than the q-axis inductance. A motor control device using values is provided.

  According to the fourth aspect, the command magnetic flux can be corrected so as to be compatible with a three-phase motor having different d-axis inductance and q-axis inductance. That is, the motor control device of the fourth aspect is advantageous for controlling a motor having magnetic saliency such as an embedded magnet synchronous motor.

According to a fifth aspect of the present disclosure, in addition to any one of the first to fourth aspects,
The command magnetic flux specifying unit provides a motor control device that corrects the command magnetic flux by adding a correction amount specified from the first inner product or the second inner product to the command magnetic flux.

  The motor control device of the fifth aspect can be simply configured.

The sixth aspect of the present disclosure includes, in addition to the fifth aspect,
The amplitude of the magnetic flux vector to be applied to the three-phase motor when the voltage vector having the limiting voltage for the weak magnetic flux control as the amplitude is applied to the three-phase motor is defined as a limiting magnetic flux. When the value obtained by subtracting the command magnetic flux is defined as the second correction amount,
The command magnetic flux specifying unit provides a motor control device that uses the second correction amount instead of the correction amount when the correction amount is larger than the second correction amount.

  The motor control device according to the sixth aspect can suitably perform the flux weakening control.

The seventh aspect of the present disclosure includes, in addition to the sixth aspect,
The command magnetic flux specifying unit provides a motor control device that uses a value obtained by dividing the limit voltage by the number of rotations of the three-phase motor as the limit magnetic flux.

  The motor control device of the seventh aspect can be configured simply.

The eighth aspect of the present disclosure is:
A motor that applies a voltage vector to the three-phase motor by using an inverter with reference to a command magnetic flux given as a magnet magnetic flux of a permanent magnet of the three-phase motor so that the motor torque of the three-phase motor follows the command torque A control device,
A magnetic flux estimator for estimating the magnet magnetic flux;
A command magnetic flux specifying unit that corrects the command magnetic flux by executing feedback control using an inner product of the estimated magnetic flux and a motor current flowing through the three-phase motor;
A motor control device comprising:

  According to the 8th aspect, the effect similar to the effect of a 1st aspect is acquired.

The ninth aspect of the present disclosure includes, in addition to the eighth aspect,
The command magnetic flux specifying unit is
(P) the deviation between the inner product and the given reference value approaches zero, or
(Q) The feedback control is executed so that the deviation between the inner product, the limit voltage for the flux-weakening control, and the reference value specified from the deviation between the amplitude of the command voltage representing the voltage vector approaches zero. A motor control device is provided.

  According to (p), the command magnetic flux is easily corrected. According to (q), the command magnetic flux is corrected so as to be adapted to the flux-weakening control.

In a tenth aspect of the present disclosure, in addition to the ninth aspect,
The command magnetic flux specifying unit is
(P) the inner product approaches zero, or
(Q) The feedback so that the deviation between the inner product and the output of the second feedback control using the deviation between the limit voltage for flux-weakening control and the amplitude of the command voltage representing the voltage vector approaches zero. A motor control device that executes control is provided.

  According to (P), the maximum torque / current control can be executed with high accuracy. According to (Q), the flux-weakening control can be executed with high accuracy.

In an eleventh aspect of the present disclosure, in addition to any one of the eighth to tenth aspects,
The command magnetic flux specifying unit provides a motor control device that corrects the command magnetic flux by adding a correction amount specified from the inner product to the command magnetic flux.

  The motor control device according to the eleventh aspect can be simply configured.

The twelfth aspect of the present disclosure includes, in addition to the eleventh aspect,
The amplitude of the magnetic flux vector to be applied to the three-phase motor when the voltage vector whose amplitude is the limiting voltage for controlling the weak magnetic flux is applied to the three-phase motor is defined as a limiting magnetic flux, When the magnetic flux component is defined as the limiting magnet magnetic flux, and the value obtained by subtracting the command magnetic flux from the limiting magnet magnetic flux is defined as the second correction amount,
The command magnetic flux specifying unit provides a motor control device that uses the second correction amount instead of the correction amount when the correction amount is larger than the second correction amount.

  The motor control device according to the twelfth aspect can suitably perform the flux weakening control.

The thirteenth aspect of the present disclosure, in addition to the twelfth aspect,
The command magnetic flux specifying unit uses, as the limiting magnetic flux, a value obtained by dividing the limiting voltage by the number of rotations of the three-phase motor, and as a component derived from the motor current in the magnetic flux vector, an inductance of the three-phase motor Provided is a motor control device that uses a product of the amplitude of the motor current and uses the square root of a value obtained by subtracting the square of the component derived from the motor current from the square of the limit magnetic flux as the limit magnet magnetic flux.

  The motor control device of the thirteenth aspect can be simply configured.

The fourteenth aspect of the present disclosure is in addition to any one of the eighth to thirteenth aspects,
The command magnetic flux specifying unit has an inductance value of the three-phase motor as a d-axis inductance value, a value larger than the d-axis inductance and smaller than the q-axis inductance, or smaller than the d-axis inductance and larger than the q-axis inductance. A motor control device using values is provided.

  According to the fourteenth aspect, the command magnetic flux can be corrected so as to be compatible with a three-phase motor having different d-axis inductance and q-axis inductance.

A fifteenth aspect of the present disclosure includes
A motor control device that applies a voltage vector to the three-phase motor using an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux and the command torque, respectively.
There is provided a motor control device including a command magnetic flux specifying unit that corrects the command magnetic flux by specifying reactive power of the three-phase motor and executing feedback control using the reactive power.

  According to the fifteenth aspect, the same effect as that of the first aspect can be obtained.

The sixteenth aspect of the present disclosure includes, in addition to the fifteenth aspect,
The command magnetic flux specifying unit provides a motor control device that specifies the reactive power using a motor current flowing through the three-phase motor and a command voltage representing the voltage vector.

The seventeenth aspect of the present disclosure includes, in addition to the fifteenth aspect,
The motor control device includes a magnetic flux estimation unit that estimates the armature flux linkage,
The command magnetic flux specifying unit is a motor control device that specifies the reactive power by multiplying the inner product of the estimated armature linkage magnetic flux and the motor current flowing through the three-phase motor by the number of revolutions of the three-phase motor. provide.

The eighteenth aspect of the present disclosure is in addition to any one of the fifteenth to seventeenth aspects,
The command magnetic flux specifying unit provides a motor control device that corrects the command magnetic flux by adding a correction amount specified from the reactive power to the command magnetic flux.

  The motor control device according to the fifteenth aspect to the eighteenth aspect can be simply configured.

A nineteenth aspect of the present disclosure includes
A generator control device that applies a voltage vector to the three-phase generator using a converter so that the armature interlinkage magnetic flux and the generator torque of the three-phase generator follow the command magnetic flux and the command torque, respectively.
A magnetic flux estimator for estimating the armature flux linkage;
(A) a first inner product of the estimated armature flux linkage and a generator current flowing through the three-phase generator, or (b) an estimated magnet flux of a permanent magnet of the three-phase generator and the A command magnetic flux specifying unit that corrects the command magnetic flux by executing feedback control using a second inner product with a generator current;
A generator control device comprising:

  According to the nineteenth aspect, an effect similar to that of the first aspect is obtained.

According to a twentieth aspect of the present disclosure,
A motor control method for applying a voltage vector to the three-phase motor using an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux and the command torque, respectively.
Estimating the armature flux linkage;
(A) a first inner product of the estimated armature flux linkage and a motor current flowing through the three-phase motor, or (b) an estimated magnet flux of the permanent magnet of the three-phase motor and the motor current. Correcting the command magnetic flux by performing feedback control using a second inner product of:
A motor control method is provided.

The twenty-first aspect of the present disclosure includes
A motor that applies a voltage vector to the three-phase motor by using an inverter with reference to a command magnetic flux given as a magnet magnetic flux of a permanent magnet of the three-phase motor so that the motor torque of the three-phase motor follows the command torque A control method,
Estimating the magnet flux;
Correcting the command magnetic flux by performing feedback control using an inner product of the estimated magnet magnetic flux and a motor current flowing through the three-phase motor;
A motor control method is provided.

According to a twenty-second aspect of the present disclosure,
A motor control method for applying a voltage vector to the three-phase motor using an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux and the command torque, respectively.
There is provided a motor control method including a step of correcting the command magnetic flux by specifying reactive power of the three-phase motor and executing feedback control using the reactive power.

A twenty-third aspect of the present disclosure provides:
A generator control method for applying a voltage vector to the three-phase generator using a converter so that an armature interlinkage magnetic flux and a generator torque of the three-phase generator follow the command magnetic flux and the command torque, respectively.
Estimating the armature flux linkage;
(A) a first inner product of the estimated armature flux linkage and a generator current flowing through the three-phase generator, or (b) an estimated magnet flux of a permanent magnet of the three-phase generator and the Correcting the command magnetic flux by performing feedback control using a second inner product with the generator current;
A generator control method is provided.

  According to the 20th to 23rd aspects, the same effect as that of the first aspect can be obtained.

  Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings.

  As shown in FIG. 1, the motor control devices 3, 103, 203, 303 according to the embodiments of the present disclosure can be connected to an inverter (voltage conversion circuit) 2 and a three-phase motor 1.

(Three-phase motor 1)
The three-phase motor 1 has a rotor and a stator. The rotor includes a permanent magnet. The stator has three-phase armature windings. The armature winding corresponding to the U phase of the three-phase motor 1 may be referred to as a U phase winding. The armature winding corresponding to the V phase of the three-phase motor 1 may be referred to as a V phase winding. The armature winding corresponding to the W phase of the three-phase motor 1 may be referred to as a W phase winding. The three-phase motor 1 may be a motor having a magnetic saliency or a motor having no magnetic saliency. Specifically, the three-phase motor 1 is a permanent magnet synchronous motor, an embedded magnet synchronous motor, or the like.

(Inverter 2)
The inverter 2 is specifically a PWM (Pulse Width Modulation) inverter. More specifically, the inverter 2 has a DC power supply and a conversion circuit. The DC power supply outputs a DC voltage. The conversion circuit converts the DC voltage into a voltage vector (three-phase AC voltage) by PWM control. The inverter 2 applies a voltage vector to the three-phase motor 1.

  Hereinafter, the motor control device may be described based on the dq coordinate system. The motor control device may be described based on the αβ coordinate system. The dq coordinate system and the αβ coordinate system are two-dimensional orthogonal coordinate systems. The dq coordinate system and the αβ coordinate system will be described with reference to FIGS. 2A and 2B.

  The dq coordinate system shown in FIG. 2A is a rotating coordinate system. The d-axis and the q-axis rotate at the same speed as the rotation speed (number of rotations) of the magnetic flux generated by the permanent magnet 1m. The counterclockwise direction is the phase advance direction. The permanent magnet 1 m represents a permanent magnet provided on the rotor of the three-phase motor 1. The d-axis is set as an axis extending in the direction of the magnetic flux generated by the permanent magnet 1m. The q-axis is set as an axis obtained by rotating the d-axis by 90 degrees in the advance direction. The U axis corresponds to the U phase winding. The V axis corresponds to the V phase winding. The W axis corresponds to the W phase winding. The U-axis, V-axis, and W-axis do not rotate even when the rotor rotates. That is, the U axis, the V axis, and the W axis are fixed axes. The angle (phase) θ is a lead angle of the d axis viewed from the U axis. The angle θ is also referred to as a rotor position or a magnetic pole position. The rotational speed ω represents the rotational speed of the rotor. In this specification, unless otherwise specified, an angle means an electrical angle. The angle between the d-axis and the q-axis, the angle θ and the rotational speed ω are values based on the electrical angle.

  The αβ coordinate system shown in FIG. 2B is a fixed coordinate system. The α axis and the β axis are fixed axes. The counterclockwise direction is the phase advance direction. The α axis is set as an axis extending in the same direction as the U axis. The β axis is set as an axis obtained by rotating the α axis by 90 degrees in the advance direction.

As shown in FIG. 1, the motor control devices 3, 103, 203, and 303 detect a three-phase current i that flows through the three-phase motor 1. The command torque T ^* is input to the motor control devices 3, 103, 203, and 303. Motor control devices 3, 103, 203, and 303 control three-phase motor 1 through inverter 2 using three-phase current i and command torque T ^* . Hereinafter, the motor control device of each embodiment will be described in order.

(First embodiment)
As shown in FIG. 3, the motor control device 3 includes a current sensor 5, a three-phase two-phase coordinate conversion unit 22, a magnetic flux / torque estimation unit 23, a subtraction unit 24, a first magnetic flux amplitude command calculation unit 25, a second Magnetic flux amplitude command calculation unit (addition unit) 31, magnetic flux amplitude command correction amount calculation unit 32 (hereinafter sometimes referred to as correction amount calculation unit 32), magnetic flux command calculation unit 26, voltage command calculation unit 29, and two-phase three-phase A coordinate conversion unit 30 is provided.

  Some or all elements of the motor control device 3 can be provided by a control application executed in a DSP (Digital Signal Processor) or a microcomputer. The DSP or microcomputer may include peripheral devices such as a core, a memory, an A / D conversion circuit, and a communication port. Further, some or all of the elements of the motor control device 3 may be configured by a logic circuit.

(Outline of control by the motor control device 3)
Hereinafter, an outline of the operation of the motor control device 3 will be described. The current sensor 5 detects the U-phase current i _u and the V-phase current i _v . U-phase current i _u is a U-phase component of three-phase current i. V-phase current i _v is a V-phase component of three-phase current i. The three-phase two-phase coordinate conversion unit 22 converts the U-phase current i _u and the V-phase current i _v into a two-phase current i _αβ . From the two-phase current i _αβ and the command two-phase voltage v _αβ ^* , the magnetic flux / torque estimation unit 23 _obtains the estimated magnetic flux ψ _αβ , the phase θ _s of the estimated magnetic flux ψ _αβ , and the estimated torque T. That is, the motor torque and the armature flux linkage are estimated by the magnetic flux / torque estimation unit 23. By the correction amount calculation unit 32, from the two-phase currents i _.alpha..beta and the estimated flux [psi _{.alpha..beta,} flux amplitude command correction amount [Delta] [phi] _S (hereinafter sometimes referred to as a correction amount [Delta] [phi] _S) is identified. The subtraction unit 24 obtains a difference (torque error ΔT: T ^* −T) between the estimated torque T and the command torque T ^* . The first magnetic flux amplitude command calculation unit 25 identifies the first command magnetic flux | ψ _S ^* | from the command torque T ^* . The second magnetic flux amplitude command calculation unit 31 uses the sum of the first command magnetic flux | ψ _S ^* | and the correction amount Δψ _S (second command magnetic flux | ψ _S ^** | = | ψ _S ^* | + Δψ _S ) Is identified. The magnetic flux command calculation unit 26 specifies the command magnetic flux vector ψ _αβ ^* from the second command magnetic flux | ψ _S ^** |, the phase θ _s, and the torque error ΔT. The voltage command calculation unit 29 specifies the command two-phase voltage v _αβ ^* from the command magnetic flux vector ψ _αβ ^* , the estimated magnetic flux ψ _αβ, and the two-phase current i _αβ . The two-phase / three-phase coordinate conversion unit 30 converts the command two-phase voltage v _αβ ^* into the command three-phase voltage v _uvw ^* . The command three-phase voltage v _uvw ^* is referred to by the inverter 2. By such control, the three-phase motor 1 is controlled such that the amplitude of the armature linkage magnetic flux and the motor torque follow the second command magnetic flux | ψ _S ^** | and the command torque T ^* , respectively.

In the present specification, the two-phase current i _αβ means a current value transmitted as information, not a current that actually flows through the three-phase motor 1. Similarly, the command two-phase voltage v _αβ ^* , the estimated magnetic flux ψ _αβ , the correction amount Δψ _S , the phase θ _s , the estimated torque T, the command torque T ^* , the first command magnetic flux | ψ _S ^* |, the second command magnetic flux | Ψ _S ^** |, the command magnetic flux vector ψ _αβ ^*, and the command three-phase voltage v _uvw ^* also mean values transmitted as information.

  Next, details of the motor control device 3 will be described.

(Current sensor 5)
The current sensor 5 detects a three-phase current i. In the present embodiment, the current sensor 5 detects the U-phase current i _u and the V-phase current i _v. Current sensor 5 outputs a U-phase current i _u and the V-phase current i _v.

(Three-phase two-phase coordinate conversion unit 22)
The three-phase two-phase coordinate conversion unit 22 converts the three-phase current i into the two-phase current i _αβ . In the present embodiment, the three-phase two-phase coordinate converter 22 converts the U-phase current i _u and the V-phase current _iv into an α-axis current i _α and a β-axis current i _β . The α-axis current i _α and the β-axis current i _β are given to the magnetic flux / torque estimation unit 23, the voltage command calculation unit 29, and the correction amount calculation unit 32.

Note that the current sensor 5 may be provided so as to measure two-phase currents of a combination other than the U-phase and V-phase two phases. Also in this case, the three-phase two-phase coordinate conversion unit 22 can be configured so that the α-axis current i _α and the β-axis current i _β are specified based on the measured current.

(Magnetic flux / torque estimation unit 23)
The magnetic flux / torque estimation unit 23 estimates the motor torque and the armature linkage magnetic flux from the two-phase current i _αβ and the command two-phase voltage v _αβ ^* . In the present embodiment, the magnetic flux / torque estimation unit 23 uses the equations (1-1), (1-2), (1-3), and (1-4) to calculate the estimated magnetic flux ψ _αβ (estimated magnetic flux ψ _α , Ψ _β ), estimated magnetic flux ψ _αβ phase θ _s and estimated torque T. R _a in the expressions (1-1) and (1-2) is _a winding resistance per phase of the three-phase motor 1. The integration on the right side represents the time integration from the reference time (t = 0) to the present time. _ψ α _{| t = 0} are the values of the estimated magnetic flux [psi _alpha at t = 0 (initial value). _ψ β _{| t = 0} are the values of the estimated magnetic flux [psi _beta at t = 0 (initial value). P _n in Expression (1-4) is the _number of pole pairs of the three-phase motor 1. The estimated magnetic flux _ψαβ is given to the voltage command calculation unit 29 and the correction amount calculation unit 32. The phase θ _s is given to the magnetic flux command calculation unit 26. The estimated torque T is given to the subtracting unit 24.

It is not essential to obtain the estimated magnetic flux _ψαβ and the estimated torque T with a single estimation unit. A magnetic flux estimation unit may be provided as an estimation unit for _{obtaining the} estimated magnetic flux _ψαβ, and a torque estimation unit may be provided as an estimation unit for obtaining the estimated torque T. Flux estimation unit includes a 2-phase currents i _{.alpha..beta,} from a command two-phase voltage v _.alpha..beta ^*, it can be configured to determine an estimated magnetic flux [psi _{.alpha..beta.} That is, the magnetic flux estimation unit can be configured to estimate the armature linkage magnetic flux based on the current flowing through the three-phase motor 1 and the voltage vector. The torque estimation unit can be configured to obtain the estimated torque T from the estimated magnetic flux _ψαβ and the two-phase current _iαβ . That is, the torque estimation unit can be configured to estimate the motor torque based on the estimated armature flux linkage and the current flowing through the three-phase motor 1.

Further, the magnetic flux / torque estimation unit 23 uses a two-phase voltage obtained by converting a detected value of a voltage applied to the three-phase motor 1 into a three-phase two-phase conversion instead of the command two-phase voltage v _αβ ^*. The estimated magnetic flux may be obtained.

(Subtraction unit 24)
The subtraction unit 24 obtains a difference (torque error ΔT: T ^* −T) between the estimated torque T and the command torque T ^* . A known operator may be used as the subtraction unit 24.

(First magnetic flux amplitude command calculation unit 25)
The first magnetic flux amplitude command calculation unit 25 specifies the first command magnetic flux | ψ _S ^* | as the command magnetic flux from the command torque T ^* . The first command magnetic flux | ψ _S ^* | is a scalar. The first command magnetic flux | ψ _S ^* | of the present embodiment is for minimizing the motor current. Control that controls a three-phase motor so that the ratio of the motor torque value to the motor current value is maximized while setting the motor torque as the target value is known as Maximum Torque Per Ampere (MTPA) control. It ’s been. In the present embodiment, the first magnetic flux amplitude command calculation unit 25 is configured to specify the first command magnetic flux | ψ _S ^* | from the command torque T ^* using a table. The first magnetic flux amplitude command calculation unit 25 may be configured to specify the first command magnetic flux | ψ _S ^* | by calculation.

A method for identifying the first command magnetic flux | ψ _S ^* | when executing the maximum torque / current control will be understood by those skilled in the art from the following description. When a motor having no magnetic saliency is used as the three-phase motor 1, the armature flux linkage amplitude | ψ _S | and the motor torque T are approximated by equations (1-5) and (1-6). The | Ψ _a0 | is a constant given as the amplitude of the magnetic flux generated by the permanent magnet 1 m in the three-phase motor 1. In the following description, | ψ _a0 | may be referred to as a magnetic flux parameter. L is the inductance per phase of the armature winding of the three-phase motor 1. i _q is a q-axis current. P _n is the number of pole pairs of the motor. The formula (1-7) is derived from the formulas (1-5) and (1-6). By substituting T for the command torque T ^* and | ψ _S | for the first command magnetic flux | ψ _S ^* |, respectively, the relational expression between the command torque T ^* and the first command magnetic flux | ψ _S ^* | It is burned. Using this relational expression, the first command magnetic flux | ψ _S ^* | can be obtained from the command torque T ^* . Of course, a conversion table can also be created.

When a motor having magnetic saliency is used as the three-phase motor 1, the armature flux linkage amplitude | ψ _S | and the motor torque T are approximated by equations (1-8) and (1-9). L _d is the d-axis inductance. L _q is a q-axis inductance. i _d is a d-axis current. The d-axis current i _d and the q-axis current i _q generally satisfy the relationship of Expression (1-10). Conversion that can specify the amplitude | ψ _S | of the armature interlinkage flux from the motor torque T without using the variables i _d and i _q by the equations (1-8), (1-9), and (1-10) A table is obtained. By replacing T with the command torque T ^* and | ψ _S | with the first command magnetic flux | ψ _S ^* |, the first command magnetic flux | ψ _S ^* | can be specified from the command torque T ^* .

(Second magnetic flux amplitude command calculation unit 31)
As described above, when the first command magnetic flux | ψ _S ^* | is specified from the command torque T ^* , the first command magnetic flux | ψ _S ^* | depends on the magnetic flux parameter | ψ _a0 |. The magnetic flux parameter | ψ _a0 | is a constant, but the magnet magnetic flux ψ _a1 produced by the actual permanent magnet of the motor may deviate from the magnetic flux parameter | ψ _a0 | due to heat or the like. In this case, the first command magnetic flux | ψ _S ^* | is deviated from a value for minimizing the motor current. In this embodiment, in order to reduce this influence, the 2nd magnetic flux amplitude command calculating part 31 is provided. That is, the second magnetic flux amplitude command calculation unit 31 corrects the first command magnetic flux | ψ _S ^* | to the second command magnetic flux | ψ _S ^** |. In the present embodiment, the second magnetic flux amplitude command calculation unit 31 uses the first command magnetic flux | ψ _S ^* | and the correction amount Δψ _S to provide the second command magnetic flux | ψ. _This is an adder that specifies _S ^** |. That is, the second command magnetic flux | ψ _S ^** | is the sum of the first command magnetic flux | ψ _S ^* | and the correction amount Δψ _S. The second command magnetic flux | ψ _S ^** | is a scalar. The correction amount Δψ _S is a correction amount specified by the correction amount calculation unit 32. Details of the correction amount calculation unit 32 and the correction amount Δψ _S will be described later. A correction coefficient K _S is output from the correction amount calculation unit 32, and the product of the first command magnetic flux | ψ _S ^* | and the correction coefficient K _S is specified in the second magnetic flux amplitude command calculation unit 31, and the product May be adopted as the second command magnetic flux | ψ _S ^** |.

(Magnetic flux command calculation unit 26)
The magnetic flux command calculation unit 26 specifies the command magnetic flux vector ψ _αβ ^* that the armature linkage flux should follow from the second command magnetic flux | ψ _S ^** |, the phase θ _s, and the torque error ΔT. The magnetic flux command calculation unit 26 in the present embodiment specifies the command magnetic flux vector _ψαβ ^* according to the block diagram shown in FIG. Specifically, the magnetic flux command calculation unit 26 includes a PI control unit 38, an addition unit 36, and a vector generation unit 37. The PI control unit 38 specifies the phase correction amount Δθ _S ^* by proportional-integral control for converging ΔT to zero. The adding unit 36 obtains the sum (θ _S ^* : θ _S + Δθ _S ^* ) of the phase θ _S and the phase correction amount Δθ _S ^* . The vector generation unit 37 specifies the command magnetic flux vector _ψαβ ^* from the second command magnetic flux | ψ _S ^** | and the total θ _S ^* . Specifically, the vector generation unit 37 obtains the command magnetic flux vector _ψαβ ^* using the equations (1-11) and (1-12). The command magnetic flux vector _ψαβ ^* is given to the voltage command calculation unit 29.

(Voltage command calculation unit 29)
The voltage command calculation unit 29 calculates the command two-phase voltage v _αβ ^* (command α-axis voltage v _α ^* and command β-axis from the difference between the command magnetic flux vector ψ _αβ ^* and the estimated magnetic flux ψ _αβ and the two-phase current i _αβ. The voltage v _β ^* ) is specified. In the present embodiment, the voltage command calculation unit 29 obtains the command two-phase voltage v _αβ ^* using Expression (1-13). T _s in Equation (1-13) is a control cycle (sampling cycle). Incidentally, when the 3-phase motor 1 is rotated at a high speed, the voltage drop based on the winding resistance R _a is very small. For this reason, the voltage command calculation unit 29 ignores the second term on the right side of the equation (1-13) and determines the command two-phase voltage v _αβ ^* from the difference between the command magnetic flux vector ψ _αβ ^* and the estimated magnetic flux ψ _αβ. It may be configured to specify. The command two-phase voltage v _αβ ^* is given to the two-phase three-phase coordinate conversion unit 30.

(2-phase 3-phase coordinate conversion unit 30)
The two-phase three-phase coordinate conversion unit 30 converts the command two-phase voltage v _αβ ^* into the command three-phase voltage v _uvw ^* . Thereafter, a voltage vector corresponding to the command three-phase voltage v _uvw ^* is generated by the inverter 2 and applied to the three-phase motor 1.

(Correction amount calculation unit 32)
The correction amount calculator 32 specifies the correction amount Δψ _S to be given to the second magnetic flux amplitude command calculator (adder) 31 from the estimated magnetic flux ψ _αβ and the two-phase current i _αβ . The correction amount Δψ _S is a scalar. In the present embodiment, the correction amount calculation unit 32 determines that the current flowing through the three-phase motor 1 when the second command magnetic flux | ψ _S ^** | is applied to the magnetic flux command calculation unit 26 is the second command magnetic flux | When the first command magnetic flux | ψ _S ^* | is given to the magnetic flux command calculation unit 26 instead of ψ _S ^** |, the current flows through the three-phase motor 1. The correction amount Δψ _S is specified by feedback control using the inner product of the estimated magnetic flux ψ _αβ and the two-phase current i _αβ .

The correction amount calculation unit 32a is shown in the block diagram of FIG. 5A. The correction amount calculation unit 32 a is an example of the correction amount calculation unit 32. The correction amount calculation unit 32 a includes an inner product calculation unit 33, an inner product command calculation unit 34 a, and a control unit (integrator) 35. The inner product calculation unit 33 calculates a first inner product of the estimated magnetic flux ψ _αβ and the two-phase current i _αβ . The inner product command calculation unit 34a calculates a reference value A from the two-phase current i _αβ . The integrator 35 generates the correction amount Δψ _S so that the difference between the first inner product and the reference value A converges to zero.

The overall operation of the correction amount calculation unit 32a can be expressed by Expression (1-14). ψ _α i _α + ψ _β i _β is the first inner product. L (i _α ² + i _β ² ) is the reference value A. C (s) is a mathematical expression representing the operation of the integrator 35. C (s) is represented by Formula (1-15). k _i is an integral gain. s is a Laplace operator.

The first magnetic flux amplitude command calculating unit 25, the correction amount calculating unit 32a, and the second magnetic flux amplitude command calculating unit 31 can be collectively referred to as a command magnetic flux specifying unit A. The command magnetic flux specifying unit A performs feedback control so that the deviation between the first inner product ψ _α i _α + ψ _β i _β and the reference value A specified from the inductance L and motor current of the three-phase motor 1 approaches zero. Run. In this embodiment, the command magnetic flux specifying unit A has a product L (i _α ² + i _β ^{2) of} the first inner product ψ _α i _α + ψ _β i _β and the inductance of the three-phase motor 1 and the square of the amplitude of the motor current. ) And feedback control is executed so that the deviation approaches zero.

The command magnetic flux specifying unit A corrects the command magnetic flux | ψ _S ^* | by adding the correction amount Δψ _S specified from the first inner product ψ _α i _α + ψ _β i _β to the command magnetic flux | ψ _S ^* |. To do. As a result, the second command magnetic flux | ψ _S ^** | is obtained.

As the correction amount calculation unit 32, a correction amount calculation unit 32b shown in FIG. 5B can also be used. The correction amount calculation unit 32 b includes an inner product calculation unit 33, an inner product command calculation unit 34 b, and an integrator 35. The inner product calculation unit 33 calculates a first inner product of the estimated magnetic flux ψ _αβ and the two-phase current i _αβ . The inner product command calculation unit 34b calculates a reference value B from the command torque T ^* . The integrator 35 generates the correction amount Δψ _S so that the difference between the first inner product and the reference value B converges to zero.

The overall operation of the correction amount calculation unit 32b can be expressed by Expression (1-16). K · T ^{* 2} is the reference value B. K is a constant determined from the relationship between the inductance L and the torque constant (torque / current).

The first magnetic flux amplitude command calculating unit 25, the correction amount calculating unit 32b, and the second magnetic flux amplitude command calculating unit 31 can be collectively referred to as a command magnetic flux specifying unit B. The command magnetic flux specifying unit B executes feedback control so that the deviation between the first inner product ψ _α i _α + ψ _β i _β and the reference value B specified from the command torque T ^{* 2} approaches zero. In the present embodiment, the command magnetic flux specifying unit B is configured such that the deviation between the first inner product ψ _α i _α + ψ _β i _β and the product K · T ^{* 2 of} the constant and the square of the command torque approaches zero. Execute feedback control.

The command magnetic flux specifying unit B also corrects the command magnetic flux | ψ _S ^* | by adding the correction amount Δψ _S specified from the first inner product ψ _α i _α + ψ _β i _β to the command magnetic flux | ψ _S ^* |. . As a result, the second command magnetic flux | ψ _S ^** | is obtained.

As the correction amount calculation unit 32, a correction amount calculation unit 32c shown in FIG. 5C can also be used. The correction amount calculation unit 32 c includes an inner product calculation unit 33, an inner product command calculation unit 34 c, an integrator 35, and a magnet magnetic flux estimation unit 39. Magnetic flux estimation unit 39, the estimated magnetic flux [psi _{.alpha..beta,} and a 2-phase currents i _{.alpha..beta,} estimates the magnet flux (obtain the estimated magnet flux [psi _a1). The magnet magnetic flux is a magnetic flux generated by the permanent magnet 1 m of the three-phase motor 1. The inner product calculation unit 33 calculates a second inner product of the estimated magnet magnetic flux ψ _a1 and the two-phase current i _αβ . The inner product command calculation unit 34c outputs a reference value C (zero). The integrator 35 generates the correction amount Δψ _S so that the difference between the second inner product and the reference value C converges to zero (so that the second inner product converges to zero).

The overall operation of the correction amount calculation unit 32c can be expressed by Expression (1-17). ψ _{a1 — α} i _α + ψ _{a1 — β} i _β is the second inner product. [psi _{A1_arufa} is α-axis component of the estimated magnet flux [psi _a1. [psi _{A1_beta} is a β-axis component of the estimated magnet flux [psi _a1. ψ _{a1 — α} and ψ _{a1 — β} are calculated by Expression (1-18). The product of L and i _α is a magnetic flux generated by the α-axis current i _α . Product of L and i _beta is the magnetic flux created by the beta-axis current i _alpha. Equation (1-18), by subtracting the magnetic flux 2-phase currents i _.alpha..beta make the estimated magnetic flux [psi _{.alpha..beta,} an equation for calculating the estimated magnet flux [psi _a1.

The first magnetic flux amplitude command calculating unit 25, the correction amount calculating unit 32c, and the second magnetic flux amplitude command calculating unit 31 may be collectively referred to as a command magnetic flux specifying unit C. The command magnetic flux specifying unit C executes feedback control so that the deviation between the second inner product ψ _{a1 — α} i _α + ψ _{a1 — β} i _β and the given reference value C approaches zero. In the present embodiment, the command magnetic flux specifying unit C executes feedback control so that the second inner product ψ _{a1 — α} i _α + ψ _{a1 — β} i _β approaches zero.

The command magnetic flux specifying unit C corrects the command magnetic flux | ψ _S ^* | by adding the correction amount Δψ _S specified from the second inner product ψ _{a1 — α} i _α + ψ _{a1 — β} i _β to the command magnetic flux | ψ _S ^* |. As a result, the second command magnetic flux | ψ _S ^** | is obtained.

  In the present embodiment, the correction amount calculation unit 32 is configured such that the equations (1-14) and (1-15), (1-16) and (1-15), or (1-17), (1- 18) and (1-15) are stored in the calculation unit. However, the correction amount calculation unit 32 may use a table corresponding to these equations.

(About the effect of this embodiment)
The effect of this embodiment will be described. In the following description, the three-phase motor 1 is a permanent magnet synchronous motor having no magnetic saliency, the d-axis inductance L _d and the q-axis inductance L _{q of} the three-phase motor 1 are the same, and reluctance torque is generated. Shall not.

In the present embodiment, the first magnetic flux amplitude command calculation unit 25 is configured for maximum torque / current control. Accordingly, the first magnetic flux amplitude command calculation unit 25 tries to generate the first command magnetic flux | ψ _S ^* | so that the motor torque follows the command torque T ^* with the minimum motor current. Specifically, the first magnetic flux amplitude command calculation unit 25 has a magnitude corresponding to the command torque T ^* , and the first magnetic flux amplitude command calculation unit 25 is configured so that a current that does not have the d-axis component and only the q-axis component flows. 1 command magnetic flux | ψ _S ^* |

Using the vector diagram of the dq coordinate system of FIG. 6, this is explained as follows. That is, the first magnetic flux amplitude command calculation unit 25 outputs the amplitude of the combined vector of the magnetic flux vector ψ _a0 and the magnetic flux vector Li _a0 as the first magnetic flux amplitude command | ψ _S ^* |. The magnetic flux vector ψ _a0 is a magnetic flux vector whose amplitude is the magnetic flux parameter | ψ _a0 |. As described above, the magnetic flux parameter | ψ _a0 | is a parameter that is used by the first magnetic flux amplitude command calculation unit 25 when the first magnetic flux amplitude command | ψ _S ^* | is determined from the command torque T ^* . The magnetic flux vector Li _a0 is a magnetic flux vector generated by the current vector i _a0 . The current vector i _a0 has a magnitude corresponding to the command torque T ^* and is a vector directed in the positive direction of the q axis. The current vector i _a0 represents the motor current. Although not shown, in FIG. 6, the horizontal axis is the d axis and the vertical axis is the q axis.

If the command magnetic flux vector _ψαβ ^* is generated in accordance with the first magnetic flux amplitude command | ψ _S ^* | as described above, it is possible to flow a current that does not have the d-axis component but only the q-axis component. Seem. However, the actual magnet flux varies with heat and the like. Therefore, the actual magnet magnetic flux amplitude may deviate from the magnetic flux parameter | ψ _a0 |. Even in such a case, the first magnetic flux amplitude command calculation unit 25 outputs the first magnetic flux amplitude command | ψ _S ^* | derived from the magnetic flux parameter | ψ _a0 |. For this reason, when the first magnetic flux amplitude command | ψ _S ^* | is directly input to the magnetic flux command calculation unit 26, a d-axis component appears in the motor current.

This phenomenon will be described with reference to FIG. The amplitude of the magnetic flux vector ψ _{a1 produced by} the actual permanent magnet of the motor may be larger than the amplitude of the magnetic flux vector ψ _a0 (the magnetic flux parameter | ψ _a0 |). Even in this case, the end point of the composite vector described above does not change. The motor control device 3 operates so that a vector extending from the end point of the magnet magnetic flux vector ψ _{a1 to} the end point of the combined vector is generated as the magnetic flux vector Li _a1 . As is apparent from FIG. 6, the amplitude of the magnetic flux vector Li _a1 is larger than the amplitude of the magnetic flux vector Li _a0 . That is, a current vector i _a1 having an amplitude larger than that of the current vector i _a0 is generated. This means that the motor current increases.

As described above, when the first magnetic flux amplitude command | ψ _S ^* | is directly input to the magnetic flux command calculation unit 26, it is difficult to minimize the motor current. In this case, the inventors analyzed by computer simulation how much the difference between the amplitude of the magnetic flux vector | ψ _a1 | and the magnetic flux parameter | ψ _a0 | affects the motor current. The results are shown in FIG. The horizontal axis of FIG. 7 represents the ratio | ψ _a0 | / | ψ _a1 | of the magnetic flux parameter | ψ _a0 | to the estimated magnetic flux amplitude | ψ _a1 |. The vertical axis represents d-axis current i _d and current vector amplitude | i _a1 |. From FIG. 7, it can be seen that when | ψ _a0 | / | ψ _a1 | = 1, the d-axis current _id is zero. This means that the motor current is minimized. In contrast, when | ψ _a0 | / | ψ _a1 | ≠ 1, the d-axis current is not zero. This means that the motor current is not minimized.

In the present embodiment, by correcting the first magnetic flux amplitude command | ψ _S ^* |, the d-axis current derived from the deviation approaches zero. This point will be described with reference to the vector diagram of FIG.

As shown in FIG. 8, the command magnetic flux specifying units A to C correct | ψ _S ^* | to | ψ _S ^* | + Δψ _s . In this way, the magnetic flux vector generated by the current vector, and the Li _a1 without Li _a2. That is, the current vector is not _ia1 , but _ia2 , and the d-axis current decreases. Specifically, the d-axis current is substantially zero.

As can be seen from FIG. 8, if the first magnetic flux amplitude command | ψ _S ^* | is corrected so that the magnetic flux vector ψ _a1 and the current vector i _a2 are orthogonal, the amplitude of the current vector i _a2 is minimized. (D-axis current becomes zero). In other words, if the first magnetic flux amplitude command | ψ _S ^* | is corrected so that the inner product of the magnetic flux vector ψ _a1 and the current vector i _a2 becomes zero, the amplitude of the current vector i _a2 is minimized.

  Formula (1-17) is derived based on this idea. The same applies to Formula (1-14) and Formula (1-16).

As described above, the motor control device 3 compensates for a decrease in control accuracy resulting from a deviation between the amplitude | ψ _a1 | of the magnet magnetic flux vector ψ _a1 and the magnetic flux parameter | ψ _a0 |. However, the motor control device 3 can compensate for a decrease in control accuracy caused by other causes. Therefore, the motor control device 3 may not perform a calculation using the magnetic flux parameter | ψ _a0 |.

An actual measurement experiment was performed for the purpose of verifying the effect exhibited by the motor control device 3 according to the present embodiment. In the measurement experiment, a command that was 10% smaller than the appropriate magnetic flux amplitude command was used as the first magnetic flux amplitude command | ψ _S ^* |. The “appropriate magnetic flux amplitude command” is that the first magnetic flux amplitude command calculation unit 25 uses the first magnetic flux amplitude using | ψ _a1 | of the correct magnetic flux vector ψ _a1 instead of the magnetic flux parameter | ψ _a0 |. A command that is output when a command is calculated. The results are shown in FIG. The horizontal axis in FIG. 9 is time. The vertical axis represents the amplitude | i _a | of the detected current vector. It can be seen that the motor current is greatly reduced from the time A when the correction of the first magnetic flux amplitude command | ψ _S ^* | is started.

(Control of a three-phase motor having magnetic saliency)
When the three-phase motor 1 has magnetic saliency, the d-axis inductance L _d and the q-axis inductance L _{q of} the three-phase motor 1 are different. Also in this case, control using the inductance L, such as control using the formula (1-14), is possible. Also in this case, control using a constant K that depends on the inductance L, such as control using Expression (1-16), is possible. Specifically, a value between the d-axis inductance and the q-axis inductance may be used as the inductance L. Further, if the magnetic saliency is not large, there is no harm in handling the L = L _d. That is, the command magnetic flux specifying units A and B are set to have an inductance value of d-axis inductance, a value larger than the d-axis inductance and smaller than the q-axis inductance, or a value smaller than the d-axis inductance and larger than the q-axis inductance. What is necessary is just to comprise so that it may be used.

Japanese Patent No. 4972135 is helpful in setting the inductance L as described above. Japanese Patent No. 4972135 describes a technique related to a dm-qm coordinate system. The dm-qm coordinate system makes it possible to treat a motor having magnetic saliency such as a permanent magnet synchronous motor having an embedded magnet structure in the same manner as a permanent magnet synchronous motor having no magnetic saliency. Specifically, maximum torque control (maximum torque / current control) can be performed by using the dm-qm coordinate system and setting the dm-axis current (γ-axis current in the control coordinate system) to zero. More specifically, when the three-phase motor 1 has magnetic saliency, the d-axis current described with reference to FIGS. 6 to 8 is changed to the dm-axis current, and the magnetic flux ψ _{a is changed} to the extended linkage magnetic flux vector Φ _exm . , the inductance L to the virtual inductance L _m, may be replaced, respectively. For details of the dm-axis current, the extended flux linkage vector Φ _exm and the virtual inductance L _m , refer to Japanese Patent No. 4972135 (Equation 36 and paragraphs 0182 to 0183). If the virtual inductance L _m is used instead of the inductance L, the expression (1-14) becomes an expression suitable for a motor having magnetic saliency. If the constant K is changed in consideration of the virtual inductance L _m , the expression (1-16) becomes an expression suitable for a motor having magnetic saliency. If the virtual inductance L _m is used instead of the inductance L, the expression (1-18) becomes an expression suitable for a motor having magnetic saliency, and an extended chain instead of the magnet magnetic flux ψ _a1 (ψ _{a1 — α} , ψ _{a1 — β} ). The flux vector Φ _exm is calculated. If this extended flux linkage vector Φ _exm is used _instead of the magnet magnetic flux ψ _a1 (ψ _{a1 — α} , ψ _{a1 — β} ), Equation (1-17) becomes an equation suitable for a motor having magnetic saliency. That is, if the virtual inductance L _m is used instead of the inductance L, Δψ _S suitable for a motor having magnetic saliency is obtained from the equations (1-14), (1-16), or (1-17). . If this Δψ _S is used, the dm-axis current becomes zero and the current becomes minimum. That is, the motor control device according to the present disclosure can be suitably used for a permanent magnet synchronous motor having an embedded magnet structure having magnetic saliency. Note that L _m satisfies L _d ≦ L _m <L _q .

In the control using Expression (1-17), in order to minimize the motor current, the reference value C is set to zero, and feedback control is performed so that the second inner product ψ _{a1 — α} i _α + ψ _{a1 — β} i _β approaches zero. When the sum of copper loss and iron loss should be minimized, the reference value C may be set to a value other than zero. The optimum reference value C can be specified by performing a computer simulation by shaking the reference value C, for example. When the motor control device 3 is operated for other purposes, the optimum reference value C can be specified in the same manner. The same applies when the control using the formula (1-14) or the formula (1-16) is used.

The coordinate system used for the calculation in the motor control device 3 is not particularly limited. For example, the estimated magnetic flux of the armature linkage flux may be based on the αβ coordinate system (ψ _αβ ), based on the dq coordinate system, or based on the γδ coordinate system. It may be based on a dm-qm coordinate system. The same applies to magnet magnetic flux and the like.

  The matters described for the motor control device in the present embodiment can also be applied to the motor control method. This also applies to the modified examples and embodiments described later.

(First modification)
It is also possible to control the three-phase motor 1 by executing feedback control using reactive power instead of inner product. That is, the command magnetic flux specifying unit may be configured to specify the reactive power of the three-phase motor 1 and correct the command magnetic flux by executing feedback control using the reactive power. The reactive power dimension includes the inner product dimension. That is, reactive power is a physical quantity including an inner product. As is clear from this, the technical significance of the control using the inner product and the technical significance of the control using the reactive power are common.

In one example, the command magnetic flux specifying unit specifies reactive power using a motor current (two-phase current i _αβ ) flowing through the three-phase motor 1 and a command voltage (command two-phase voltage v _αβ ^* ) representing a voltage vector. Configured. In another example, the command magnetic flux specifying unit is invalidated by multiplying the inner product of the estimated armature flux linkage (estimated magnetic flux ψ _αβ ) and the motor current flowing through the three-phase motor 1 by the rotational speed ω of the three-phase motor 1. Configured to identify power.

  The motor control device according to the first modification is configured similarly to the motor control device 3. Therefore, as in the previous embodiment, the command magnetic flux specifying unit in the first modification corrects the command magnetic flux by adding the correction amount specified from the reactive power to the command magnetic flux.

(Second modification)
There are other motor control methods than the RFVC DTC. For example, a direct torque control method using a switching table is also known. Even when this control method is adopted, the same control as that described above can be executed. The control will be described with reference to FIG. In the second modified example, the same reference numerals are given to the same parts as those in the above-described embodiment, and the description thereof is omitted.

  The motor control device 103 illustrated in FIG. 10 does not include the magnetic flux command calculation unit 26, the voltage command calculation unit 29, and the two-phase / three-phase coordinate conversion unit 30. The motor control device 103 includes a magnetic flux / torque estimation unit 23 b instead of the magnetic flux / torque estimation unit 23. The motor control device 103 includes a voltage sensor 41, a three-phase / two-phase coordinate conversion unit 42, a subtraction unit 43, and a magnetic flux / torque control unit 44. Other components of the motor control device 103 are the same as those of the motor control device 3.

(Voltage sensor 41)
The voltage sensor 41 detects a three-phase voltage v _uvw (v _u , v _v , v _w ).

(3-phase 2-phase coordinate conversion unit 42)
The three-phase two-phase coordinate conversion unit 42 converts the three-phase voltage v _uvw into a two-phase voltage v _αβ .

(Magnetic flux / torque estimation unit 23b)
The magnetic flux / torque estimation unit 23b estimates the motor torque and the armature linkage magnetic flux from the two-phase current i _αβ and the two-phase voltage v _αβ . Specifically, the magnetic flux torque estimation section 23b estimates the flux [psi _{.alpha..beta,} estimated magnetic flux [psi _.alpha..beta amplitude | [psi _.alpha..beta |, determine an estimated magnetic flux [psi _.alpha..beta phase theta _s and the estimated torque T. And that it uses a two-phase voltage v _.alpha..beta instead of command two-phase voltage v _.alpha..beta ^*, the estimated magnetic flux [psi _.alpha..beta amplitude | [psi _.alpha..beta | except a point that generates and outputs a flux-torque estimation section 23b flux- The operation is similar to that of the torque estimation unit 23.

(Subtraction unit 43)
The subtracting unit 43 obtains a deviation Δψ = | ψ _S ^** | − | ψ _αβ | between the second command magnetic flux | ψ _S ^** | and the amplitude | ψ _αβ | of the estimated magnetic flux ψ _αβ . As the subtraction unit 43, a known operator may be used.

(Magnetic flux / torque controller 44)
Flux torque control unit 44, from the deviation [Delta] [phi], and the torque error [Delta] T, the estimated magnetic flux [psi _.alpha..beta phase theta _s, generates switching signals S1 to S6. Since the direct torque control method using the switching table is known, those skilled in the art can appropriately configure the magnetic flux / torque control unit 44. The specific configuration of the magnetic flux / torque control unit 44 is disclosed in a publicly known document (star, two others: “torque response speed increasing magnetic flux command value input method to a direct torque controller for embedded permanent magnet synchronous motor”, 2004. Annual Electrical Society Industry Application Division Conference Proceedings, 1-15, pp.I-183-188, etc.).

  The motor control device 103 has the same effect as the motor control device 3.

(Second Embodiment)
Hereinafter, the motor control device 203 of the second embodiment will be described with reference to FIG. Note that in the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The motor control device 203 replaces the magnetic flux / torque estimator 23, the magnetic flux command calculator 26, the voltage command calculator 29, the second magnetic flux amplitude command calculator 31 and the correction amount calculator 32 with a magnetic flux / torque estimator 50. , A magnetic flux command calculation unit 26b, a voltage command calculation unit 29b, a magnetic flux amplitude command calculation unit 31b, and a magnetic flux amplitude command correction amount calculation unit 51 (hereinafter sometimes referred to as a correction amount calculation unit 51). The motor control device 203 does not have the first magnetic flux amplitude command calculation unit 25. Other components of the motor control device 203 are the same as those of the motor control device 3. The motor control device 203 receives the first command magnetic flux | ψ _a0 ^* |. The first command magnetic flux | ψ _a0 ^* | is a constant given as the magnetic flux of the permanent magnet 1 m of the three-phase motor 1. The first command magnetic flux | ψ _a0 ^* | is a scalar. The first command magnetic flux | ψ _a0 ^* | corresponds to the magnetic flux parameter | ψ _a0 |. In the present embodiment, the first command magnetic flux | ψ _a0 ^* | is the same as the magnetic flux parameter | ψ _a0 |.

(Magnetic flux / torque estimation unit 50)
The magnetic flux / torque estimation unit 50 estimates the motor torque and the magnet magnetic flux from the two-phase current i _αβ and the command two-phase voltage v _αβ ^* . Specifically, the magnetic flux / torque estimator 50 uses the equations (2-1), (2-2), (2-3), and (2-4) to estimate the magnetic flux ψ _m (estimated magnetic flux ψ _mα , ψ _mβ ), the estimated magnetic flux ψ _m , the phase θ _s, and the estimated torque T. The estimated magnet magnetic flux ψ _m represents the same as the estimated magnet magnetic flux ψ _a1 described above.

(Magnetic flux amplitude command calculation unit 31b)
The magnetic flux amplitude command calculation unit 31b corrects the first command magnetic flux | ψ _a0 ^* | to the second command magnetic flux | ψ _m ^* |. The second command magnetic flux | ψ _m ^* | is a scalar. In the present embodiment, the magnetic flux amplitude command calculation unit 31b is an addition unit. That is, the second command magnetic flux | ψ _m ^* | is the sum of the first command magnetic flux | ψ _a0 ^* | and the correction amount Δψ _S. The correction amount Δψ _S is the correction amount specified by the correction amount calculation unit 51. Details of the correction amount calculation unit 51 and the correction amount Δψ _S will be described later.

(Magnetic flux command calculation unit 26b)
The magnetic flux command calculation unit 26b specifies the command magnetic flux vector ψ _m ^* from the second command magnetic flux | ψ _m ^* |, the phase θ _s, and the torque error ΔT. The magnetic flux command calculation unit 26b in the present embodiment is the same as the magnetic flux command calculation unit 26 except that the second command magnetic flux | ψ _m ^* | is used instead of the second command magnetic flux | ψ _S ^** |. The command magnetic flux vector ψ _m ^* is specified. Further, the magnetic flux command calculation unit 26b of the present embodiment outputs the phase correction amount Δθ _S ^* .

(Voltage command calculation unit 29b)
The voltage command calculation unit 29b identifies the command two-phase voltage v _αβ ^* from the difference between the command magnetic flux vector ψ _m ^* and the estimated magnet magnetic flux ψ _m , the two-phase current i _αβ, and the phase correction amount Δθ _S ^*. . In the present embodiment, the voltage command calculation unit 29b specifies the command two-phase voltage v _αβ ^* using the equations (2-5a) and (2-5b).

(Correction amount calculation unit 51)
The correction amount calculator 51 specifies the correction amount Δψ _S to be given to the magnetic flux amplitude command calculator (adder) 31b from the estimated magnet magnetic flux ψ _m and the two-phase current i _αβ . The correction amount Δψ _S is specified by feedback control using the inner product of the estimated magnet magnetic flux ψ _m and the two-phase current i _αβ .

FIG. 12 shows a block diagram of the correction amount calculation unit 51. The correction amount calculation unit 51 includes an inner product calculation unit 33, an inner product command calculation unit 34 c, and an integrator (control unit) 35. The inner product calculation unit 33 calculates the inner product of the estimated magnet magnetic flux ψ _m and the two-phase current i _αβ . The inner product command calculation unit 34c outputs a reference value D (zero). The integrator 35 generates the correction amount Δψ _S so that the difference between the inner product and the reference value D converges to zero (so that the inner product converges to zero). That is, the correction amount calculation unit 51 specifies the correction amount Δψ _S from the estimated magnet magnetic flux ψ _m and the two-phase current i _αβ .

The overall operation of the correction amount calculation unit 51 can be expressed by Expression (2-6). ψ _mα i _α + ψ _mβ i _β is an inner product. C (s) is a mathematical expression representing the operation of the integrator 35. C (s) is represented by Formula (1-15).

The magnetic flux amplitude command calculating unit 31b and the correction amount calculating unit 51 can be collectively referred to as a command magnetic flux specifying unit D. The command magnetic flux specifying unit D executes feedback control so that the deviation between the inner product ψ _mα i _α + ψ _mβ i _β and the given reference value D approaches zero. In the present embodiment, the command magnetic flux specifying unit D executes feedback control so that the inner product ψ _mα i _α + ψ _mβ i _β approaches zero. As can be understood from the equations (1-17), (1-18), and (2-6), the inner product of the second embodiment corresponds to the second inner product of the first embodiment.

The command magnetic flux specifying unit D corrects the command magnetic flux | ψ _a0 ^* | by adding the correction amount Δψ _S specified from the inner product ψ _mα i _α + ψ _mβ i _β to the command magnetic flux | ψ _a0 ^* |. As a result, the second command magnetic flux | ψ _m ^* | is obtained.

In the first embodiment, the first magnetic flux amplitude command calculating unit 25 is in charge of maximum torque / current (MTPA) control, and the correction amount calculating unit 32 is a correction for increasing the accuracy of the control. Specify and output quantities. On the other hand, in the second embodiment, the correction amount calculation unit 51 is in charge of the maximum torque / current control alone. However, the correction amount calculation unit 51 uses the estimated magnet magnetic flux ψ _m for this control. The estimated magnet magnetic flux ψ _m is not a constant given from the outside of the three-phase motor 1 but an actual magnet magnetic flux generated by the permanent magnet 1 m of the three-phase motor 1. Therefore, also in the second embodiment, the maximum torque / current can be executed with high accuracy. As described in the previous embodiment, since the magnetic flux generated by the permanent magnet of the actual motor varies with heat or the like, the constant first command magnetic flux | ψ _a0 ^* | When inputting to 26b, it is difficult to execute the maximum torque / current control with high accuracy.

The effect of this embodiment is demonstrated using FIG. FIG. 13 is a diagram illustrating a simulation result. The horizontal axis in FIG. 13 represents the ratio | ψ _m ^* | / | ψ _a0 ^* | of the second command magnetic flux | ψ _m ^* | to the first command magnetic flux | ψ _a0 ^* |. The vertical axis represents the ratio T / | i _αβ | of the estimated torque T to the inner product ψ _m · i _αβ of the estimated magnet magnetic flux ψ _m and the two-phase current i _αβ and the amplitude | i _αβ | of the two-phase current i _αβ . From FIG. 13, it is understood that the ratio T / | i _αβ | is maximized when the inner product ψ _m · i _αβ is zero.

  As in the previous embodiment, the control of the present embodiment can be applied to a motor having a magnetic saliency or a motor having no magnetic saliency.

(Third embodiment)
Hereinafter, the motor control device 303 of the third embodiment will be described with reference to FIG. Note that in the third embodiment, the same portions as those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

  The motor control device 303 includes a correction amount calculation unit 51 b instead of the correction amount calculation unit 51. In addition, the motor control device 303 has a flux weakening control unit 52. Other components of the motor control device 303 are the same as those of the motor control device 203.

(Weak magnetic flux controller 52)
The flux weakening control unit 52 specifies the inner product command r ^* from the limit voltage V _om and the amplitude | v _αβ ^* | of the command two-phase voltage v _αβ ^* . The limit voltage V _om defines the upper limit value of the voltage (magnitude of voltage vector) applied to the three-phase motor 1 in the flux weakening control. The inner product command r ^* is a value that the inner product ψ _mα i _α + ψ _mβ i _β should converge. Specifically, the flux-weakening control unit 52 calculates the inner product command r ^* using Equation (3-1). C _fw (s) is a control unit for matching the limit voltage V _om with the amplitude | v _αβ ^* |. This control unit is, for example, a PI controller.

As understood from the equation (3-1), when the limiting voltage V _om is smaller than the amplitude | v _αβ ^* |, the inner product command r ^{* is represented} as C _fw (s) (V _om − | v _αβ ^* |). Is output. When the limit voltage V _om is greater than or equal to the amplitude | v _αβ ^* |, zero is output as the inner product command r ^* .

(Correction amount calculation unit 51b)
The correction amount calculation unit 51b specifies the correction amount Δψ _S from the estimated magnet magnetic flux ψ _m , the two-phase current i _αβ, and the inner product command r ^* .

The block diagram of FIG. 15 shows the correction amount calculation unit 51b. The correction amount calculation unit 51 b includes an inner product calculation unit 33 and an integration unit (control unit) 35. The inner product calculation unit 33 calculates the inner product ψ _mα i _α + ψ _mβ i _β of the estimated magnet magnetic flux ψ _m and the two-phase current i _αβ . The integrator 35 generates the correction amount Δψ _S so that the difference between the inner product ψ _mα i _α + ψ _mβ i _β and the inner product command r ^* converges to zero.

The magnetic flux amplitude command calculation unit 31b, the correction amount calculation unit 51b, and the weakening magnetic flux control unit 52 can be collectively referred to as a command magnetic flux specifying unit E. The command magnetic flux specifying unit E is specified from the _deviation between the inner product ψ _mα i _α + ψ _mβ i _β , the limit voltage V _om for controlling the flux weakening, and the amplitude | v _αβ ^* | of the command voltage v _αβ ^* representing the voltage vector. The feedback control is executed so that the deviation from the reference value E approaches zero. In the present embodiment, the command magnetic flux specifying unit E executes feedback control so that the deviation between the inner product ψ _mα i _α + ψ _mβ i _β and the inner product command r ^* approaches zero. The inner product command r ^* is an output of the second feedback control in which a deviation between the limit voltage V _om for the flux-weakening control and the amplitude | v _αβ ^* | of the command voltage v _αβ ^* representing the voltage vector is input.

The command magnetic flux specifying unit E corrects the command magnetic flux | ψ _a0 ^* | by adding the correction amount Δψ _S specified from the inner product ψ _mα i _α + ψ _mβ i _β to the command magnetic flux | ψ _a0 ^* |. As a result, the second command magnetic flux | ψ _m ^* | is obtained.

According to the present embodiment, the correction amount Δψ _S is calculated so that the amplitude | v _αβ ^* | of the command two-phase voltage v _αβ ^* is suppressed to the limit voltage _Vom or less. This correction amount Δψ _S is specified using the estimated magnet magnetic flux ψ _m . The estimated magnet magnetic flux ψ _m is not a constant given from the outside of the three-phase motor 1 but an actual magnet magnetic flux generated by the permanent magnet 1 m of the three-phase motor 1. Therefore, according to the present embodiment, the flux-weakening control can be executed with high accuracy.

(Third Modification)
In addition, the same weak magnetic flux control of this embodiment is provided by providing a weak magnetic flux control unit similar to the weak magnetic flux control unit 52 in the motor control device 3 shown in FIG. 3 and changing the calculation content of the correction amount calculation unit 32a. Magnetic flux weakening control can also be performed. Specifically, a flux weakening control unit may be newly provided so as to output the inner product command r ^* according to the equation (3-2). Further, the configuration of the correction amount calculation unit 32a may be changed so that the inner product command r ^* is used instead of the output of the inner product command calculation unit 34a shown in FIG. 5A.

(Fourth modification)
Further, as shown in FIG. 5B, a magnetic flux weakening control unit is newly provided to output the inner product command r ^* according to the equation (3-3), and the inner product command r ^* is used instead of the output of the inner product command calculation unit 34b. The configuration of the correction amount calculation unit 32b may be changed.

(Fifth modification)
Further, as shown in FIG. 5C, a weak flux control unit using Equation (3-1) is newly provided in the same manner as the weak flux control unit 52, and the inner product command r ^* is used instead of the output of the inner product command calculation unit 34c. The configuration of the correction amount calculation unit 32c may be changed.

Regarding the third modification, the fourth modification, or the fifth modification, the first magnetic flux amplitude command calculation unit 25, the changed correction amount calculation unit 32a, 32b or 32c, and the second magnetic flux amplitude command calculation unit 31 and the newly provided weak flux control unit can be collectively referred to as a command magnetic flux specifying unit F. The command magnetic flux specifying unit F includes the first inner product ψ _α i _α + ψ _β i _β or the second inner product ψ _{a1 —α} i _α + ψ _{a1 —β} i _β , the limit voltage for the flux weakening control, and the amplitude of the command voltage representing the voltage vector Feedback control is executed so that the deviation between the reference value F (inner product command r ^* ) identified from the deviation approaches zero. In the third modification example, the fourth modification example, or the fifth modification example, the first inner product ψ _α i _α + ψ _β i _β or the second inner product ψ _{a1 —α} i _α + ψ _{a1 —β} i _β and the restriction for weakening magnetic flux control The feedback control is executed so that the deviation between the output of the second feedback control (inner product command r ^* ) input with the deviation between the voltage and the amplitude of the command voltage representing the voltage vector approaches zero.

The command magnetic flux specifying unit F _adds the correction amount Δψ _S specified from the first inner product ψ _α i _α + ψ _β i _β or the second inner product ψ _{a1 —α} i _α + ψ _{a1 —β} i _β to the command magnetic flux | ψ _S ^* |. To correct the command magnetic flux | ψ _S ^* |. As a result, the second command magnetic flux | ψ _S ^** | is obtained.

(Sixth Modification)
The motor control device 203 shown in FIG. 11 can be modified so that the flux-weakening control in a mode different from the third embodiment can be performed. Specifically, when the correction amount Δψ _s exceeds Δψ _amax in Expression (3-4), a correction amount limiting unit (not shown) is provided that causes the magnetic flux amplitude command calculation unit 31b to input Δψ _amax instead of Δψ _s. Just do it. The limit magnet magnetic flux ψ _amax is calculated by Expression (3-5).

In this way, the input to the magnetic flux command calculation unit 26b is suppressed to the limit magnet magnetic flux ψ _amax or less. As a result, the amplitude | v _αβ ^* | of the two-phase voltage command is suppressed below the limit voltage V _om . That is, the flux weakening control can be executed.

The magnetic flux amplitude command calculating unit 31b, the correction amount calculating unit 51, and the correction amount limiting unit can be collectively referred to as a command magnetic flux specifying unit G. Command flux particular section G is the correction amount [Delta] [phi] when _S is larger than the second correction amount [Delta] [phi] _amax, using the second correction amount [Delta] [phi] _amax instead of the correction amount [Delta] [phi] _S. The second correction amount Δψ _amax is a value obtained by subtracting the command magnetic flux | ψ _a0 ^* | from the limit magnet magnetic flux ψ _amax . The limit magnet magnetic flux ψ _amax is a component of the magnetic flux in the magnetic flux vector to be applied to the three-phase motor 1 when a voltage vector having the amplitude of the limit voltage V _om for controlling the weak magnetic flux is applied to the three-phase motor 1. is there. In this embodiment, the command magnetic flux specifying unit G uses a value V _om / ω obtained by dividing the limit voltage by the number of rotations of the three-phase motor as the limit magnetic flux ψ _max that is the amplitude of the magnetic flux vector. As a derived component, the product L (i _α ² + i _β ² ) ^1/2 of the inductance of the three-phase motor and the amplitude of the motor current is used, and the limit magnetic flux is the square of the limit magnetic flux (V _om / ω) ^2. The square root of the value obtained by subtracting the square L ² (i _α ² + i _β ² ) of the component derived from the motor current is used.

(Seventh Modification)
The motor control device 3 shown in FIG. 3 can be modified so that the flux-weakening control in a different form from the first modification, the second modification, and the third modification can be performed. Specifically, when the magnetic flux amplitude correction amount Δψ _s exceeds Δψ _smax in Expression (3-6), a correction amount limiting unit (not _shown) that inputs Δψ _smax instead of Δψ _s to the second magnetic flux amplitude command calculation unit 31 ( (Not shown) may be provided. The limit magnetic flux ψ _max is calculated by Expression (3-7).

In this way, the input to the magnetic flux command calculation unit 26 is suppressed to the limit magnetic flux ψ _max or less. As a result, the amplitude | v _αβ ^* | of the two-phase voltage command is suppressed below the limit voltage V _om . That is, the flux weakening control can be executed.

The first magnetic flux amplitude command calculating unit 25, the magnetic flux amplitude command calculating unit 31, the correction amount calculating unit 32, and the correction amount limiting unit can be collectively referred to as a command magnetic flux specifying unit H. Command flux particular section H, the correction amount [Delta] [phi] when _S is larger than the second correction amount [Delta] [phi] _smax, using the second correction amount [Delta] [phi] _smax instead of the correction amount [Delta] [phi] _S. The second correction amount Δψ _smax is a value obtained by subtracting the command magnetic flux | ψ _S ^* | from the limit magnetic flux ψ _max . The limit magnetic flux ψ _max is the amplitude of the magnetic flux vector to be applied to the three-phase motor 1 when a voltage vector having an amplitude of the limit voltage V _om for controlling the weak magnetic flux is applied to the three-phase motor 1. In the present embodiment, the command magnetic flux specifying unit H uses a value V _om / ω obtained by dividing the limit voltage by the rotation speed of the three-phase motor 1 as the limit magnetic flux ψ _max .

(Fourth embodiment)
Hereinafter, the generator control apparatus of 4th Embodiment is demonstrated. The generator control device 403 shown in FIG. 16 can be connected to the converter (voltage conversion circuit) 2b and the three-phase generator 1b. The components of the generator control device 403 are the same as those of the motor control device 3.

  The three-phase generator 1b is a three-phase permanent magnet synchronous generator. Examples of the three-phase permanent magnet synchronous generator include an embedded magnet synchronous generator. The three-phase generator 1 b has the same configuration as that of the three-phase motor 1. Converter 2 b has the same configuration as inverter 2. Converter 2b is a PWM converter.

The three-phase generator 1b is connected to a turbine, for example. An example of the turbine is a small gas turbine. When the turbine rotates, the torque of the turbine is transmitted to the rotor of the three-phase generator 1b. As a result, the rotor rotates. A voltage is induced by the rotation of the rotor. Since the three-phase generator 1b is connected to the converter 2b and the converter 2b refers to the command three-phase voltage v _uvw ^* , the induced voltage follows the command three-phase voltage v _uvw ^* . The converter 2b also converts the induced voltage into a DC voltage by PWM modulation. The DC voltage (DC power derived from the DC voltage) is output from the voltage output unit 4b.

  In the embodiment described above, electric power supplied from a power source (not shown) is converted into torque (rotational force) by the three-phase motor 1. On the other hand, in this embodiment, the torque applied to the three-phase generator 1b is converted into electric power. In both cases, the control aspects are substantially the same. Therefore, the matters described for the motor control device 3 can also be applied to the generator control device 403. The matters described for the motor control devices 103, 203, and 303 are the same. However, it should be noted that the terminology should be replaced when the description of the motor control devices 3, 103, 203, and 303 is used for the description of the generator control device 403. Since such replacement is obvious to those skilled in the art and will not be described in detail, for example, a motor and an inverter should be replaced with a generator and a converter, respectively. Further, the items described for the generator control device 403 can be applied to the generator control method.

DESCRIPTION OF SYMBOLS 1 3 phase motor 1b 3 phase generator 1m Permanent magnet 2 Inverter 2b Converter 3,103,203,303 Motor controller 4b Voltage output part 5 Current sensor 22 Three phase 2 phase coordinate conversion part 23,23b, 50 Magnetic flux and torque estimation Unit 24 subtraction unit 25 first magnetic flux amplitude command calculation unit 26, 26b magnetic flux command calculation unit 29, 29b voltage command calculation unit 30 two-phase three-phase coordinate conversion unit 31, 31b (second) magnetic flux amplitude command calculation unit 32, 32a, 32b, 32c, 51, 51b Magnetic flux amplitude command correction amount calculation unit 33 Inner product calculation unit 34a, 34b, 34c Inner product command calculation unit 35 Control unit 36 Addition unit 37 Vector generation unit 38 PI control unit 39 Magnet magnetic flux estimation unit 41 Voltage Sensor 42 Three-phase two-phase coordinate conversion unit 43 Subtraction unit 44 Magnetic flux / torque control unit 52 Weak magnetic flux control unit 403 Generator control Equipment

Claims (19)

A motor control device that applies a voltage vector to the three-phase motor using an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux and the command torque, respectively.
A magnetic flux estimator for estimating the armature flux linkage;
(A) a first inner product of the estimated armature flux linkage and a motor current flowing through the three-phase motor, or (b) an estimated magnet flux of the permanent magnet of the three-phase motor and the motor current. A command magnetic flux specifying unit that corrects the command magnetic flux by executing feedback control using the second inner product of
A motor control device comprising: The command magnetic flux specifying unit is
(J) The deviation between the first inner product and the reference value specified from the inductance of the three-phase motor and the motor current approaches zero.
(K) The deviation between the first inner product and the reference value specified from the command torque approaches zero.
(L) The deviation between the second inner product and the given reference value approaches zero, or
(M) The deviation between the first inner product or the second inner product and the reference value specified from the deviation between the limit voltage for the magnetic flux weakening control and the amplitude of the command voltage representing the voltage vector is close to zero. The motor control device according to claim 1, wherein the feedback control is executed. The command magnetic flux specifying unit is
(J) The deviation between the first inner product and the product of the inductance of the three-phase motor and the square of the amplitude of the motor current approaches zero.
(K) The deviation between the first inner product and the product of the constant and the square of the command torque approaches zero.
(L) the second inner product approaches zero, or
(M) The deviation between the first inner product or the second inner product and the output of the second feedback control that receives the deviation between the limit voltage for the flux-weakening control and the amplitude of the command voltage representing the voltage vector is zero. The motor control device according to claim 2, wherein the feedback control is executed so as to approach the value.   The command magnetic flux specifying unit has an inductance value of the three-phase motor as a d-axis inductance value, a value larger than the d-axis inductance and smaller than the q-axis inductance, or smaller than the d-axis inductance and larger than the q-axis inductance. The motor control device according to claim 1, wherein a value is used.   The said command magnetic flux specific | specification part correct | amends the said command magnetic flux by adding the correction amount specified from the said 1st inner product or the said 2nd inner product to the said command magnetic flux, The any one of Claims 1-4. Motor control device. The amplitude of the magnetic flux vector to be applied to the three-phase motor when the voltage vector having the limiting voltage for the weak magnetic flux control as the amplitude is applied to the three-phase motor is defined as a limiting magnetic flux. When the value obtained by subtracting the command magnetic flux is defined as the second correction amount,
The motor control device according to claim 5, wherein the command magnetic flux specifying unit uses the second correction amount instead of the correction amount when the correction amount is larger than the second correction amount.   The motor control device according to claim 6, wherein the command magnetic flux specifying unit uses a value obtained by dividing the limit voltage by the number of rotations of the three-phase motor as the limit magnetic flux. A motor that applies a voltage vector to the three-phase motor by using an inverter with reference to a command magnetic flux given as a magnet magnetic flux of a permanent magnet of the three-phase motor so that the motor torque of the three-phase motor follows the command torque A control device,
A magnetic flux estimator for estimating the magnet magnetic flux;
A command magnetic flux specifying unit that corrects the command magnetic flux by executing feedback control using an inner product of the estimated magnetic flux and a motor current flowing through the three-phase motor;
A motor control device comprising: The command magnetic flux specifying unit is
(P) the deviation between the inner product and the given reference value approaches zero, or
(Q) The feedback control is executed so that the deviation between the inner product, the limit voltage for the flux-weakening control, and the reference value specified from the deviation between the amplitude of the command voltage representing the voltage vector approaches zero. The motor control device according to claim 8. The command magnetic flux specifying unit is
(P) the inner product approaches zero, or
(Q) The feedback so that the deviation between the inner product and the output of the second feedback control using the deviation between the limit voltage for flux-weakening control and the amplitude of the command voltage representing the voltage vector approaches zero. The motor control device according to claim 9, wherein control is executed.   The motor control device according to any one of claims 8 to 10, wherein the command magnetic flux specifying unit corrects the command magnetic flux by adding a correction amount specified from the inner product to the command magnetic flux. The amplitude of the magnetic flux vector to be applied to the three-phase motor when the voltage vector whose amplitude is the limiting voltage for controlling the weak magnetic flux is applied to the three-phase motor is defined as a limiting magnetic flux, When the magnetic flux component is defined as the limiting magnet magnetic flux, and the value obtained by subtracting the command magnetic flux from the limiting magnet magnetic flux is defined as the second correction amount,
The motor control device according to claim 11, wherein the command magnetic flux specifying unit uses the second correction amount instead of the correction amount when the correction amount is larger than the second correction amount.   The command magnetic flux specifying unit uses, as the limiting magnetic flux, a value obtained by dividing the limiting voltage by the number of rotations of the three-phase motor, and as a component derived from the motor current in the magnetic flux vector, an inductance of the three-phase motor The square root of a value obtained by subtracting the square of the component derived from the motor current from the square of the limit magnetic flux is used as the limit magnet magnetic flux, using a product of the amplitude of the motor current. Motor control device.   The command magnetic flux specifying unit has an inductance value of the three-phase motor as a d-axis inductance value, a value larger than the d-axis inductance and smaller than the q-axis inductance, or smaller than the d-axis inductance and larger than the q-axis inductance. The motor control device according to claim 8, wherein a value is used. A motor control device that applies a voltage vector to the three-phase motor using an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux and the command torque, respectively.
The motor control apparatus provided with the command magnetic flux specific | specification part which correct | amends the said command magnetic flux by specifying the reactive power of the said 3-phase motor, and performing the feedback control using the said reactive power.   The motor control device according to claim 15, wherein the command magnetic flux specifying unit specifies the reactive power using a motor current flowing through the three-phase motor and a command voltage representing the voltage vector. The motor control device includes a magnetic flux estimation unit that estimates the armature flux linkage,
The said command magnetic flux specific | specification part specifies the said reactive power by multiplying the inner product of the estimated said armature linkage magnetic flux and the motor current which flows through the said three-phase motor by the rotation speed of the said three-phase motor. The motor control device described in 1.   The motor control device according to claim 15, wherein the command magnetic flux specifying unit corrects the command magnetic flux by adding a correction amount specified from the reactive power to the command magnetic flux. A generator control device that applies a voltage vector to the three-phase generator using a converter so that the armature interlinkage magnetic flux and the generator torque of the three-phase generator follow the command magnetic flux and the command torque, respectively.
A magnetic flux estimator for estimating the armature flux linkage;
(A) a first inner product of the estimated armature flux linkage and a generator current flowing through the three-phase generator, or (b) an estimated magnet flux of a permanent magnet of the three-phase generator and the A command magnetic flux specifying unit that corrects the command magnetic flux by executing feedback control using a second inner product with a generator current;
A generator control device comprising:

Images