JP2001086797A - Control device of permanent-magnet synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately control torque by providing a function for automatically measuring and setting iron loss conductance of a permanent-magnet synchronous motor. SOLUTION: A switch 5 for switching between the output of a torque control means 3 and the first output of a current control means 4, and a power converter 2 for supplying power to an electric motor 1 with the output of the switch 5 as command input, are provided. Then, a means 6 for measuring the amount of input for outputting each value of the voltage/current and power applied to the electric motor 1 is provided, and the output of the means 6 for measuring the amount of input, the second output of the current control means 4, and the first output of a setting storage means 8 are inputted to an iron loss operation means 7. Then, the output of the iron loss operation means 7 is inputted to the setting storage means 8, a magnetic flux operation means 9 with the output of the means 6 for measuring the amount of input and the first output of the setting storage means 8 as input is provided, and the output and the second output of the setting storage means 8 are inputted to an iron loss torque operation means 10. Then, an iron loss correction means 11 with the output and a torque command as the input is connected to a torque control means 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-precision torque control in a permanent magnet synchronous motor, and more particularly to a technique for automatically measuring and setting an electric constant of the motor necessary for the control.

[0002]

2. Description of the Related Art To determine the iron loss conductance, which is the electrical constant of a permanent magnet type synchronous motor, an alternating current is passed through the permanent magnet type synchronous motor, and the input current, input voltage and input power are measured. However, since the measurement work is complicated, the iron loss conductance was not actively taken into consideration even when performing torque control on the permanent magnet synchronous motor.

[0003]

In order to control a permanent magnet type synchronous motor with high accuracy, it is indispensable to grasp accurate electric constants of the motor. Work and various measuring instruments were required. SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object the purpose of automatically measuring and setting the iron loss conductance of a permanent magnet type synchronous motor to provide a function for setting the iron loss conductance. It is an object of the present invention to solve the problems and to use the iron loss conductance of the motor for control, thereby enabling high-precision torque control in a permanent magnet type synchronous motor.

[0004]

In order to solve the above-mentioned problems, a switch for switching between an output of a torque control means having a torque command input and a first output of a current control means, and the output of the switch is used as a command input for the electric motor. A power converter for supplying power to the motor, and input amount measuring means for outputting respective values of voltage / current and electric power applied to the electric motor. Two outputs and a first output of the setting storage means are provided as inputs, and iron loss calculation means is provided.The output of the iron loss calculation means is input to the setting storage means. A magnetic flux calculating means having a first output as an input, iron loss torque calculating means having the output and a second output of the setting storage means as inputs, and an iron loss having the output and a torque command as inputs; Correction means output Configure connected to the torque control means.

[0005]

FIG. 1 shows an embodiment of the present invention, which will be described with reference to FIG. The switch 5 selects the output of the torque control unit 3 as a command input to the power converter 2 during normal operation, and sets and stores the iron loss conductance g0 of the permanent magnet type synchronous motor 1 in the setting storage unit 8. Selects the output of the current control means 4 as a command input to the power converter 2.

The first output of the current control means 4 outputs two signals through which three-phase alternating currents having different magnitudes flow at a predetermined frequency fr. By these two signals, the motor 1
Operates in two different current modes at a speed corresponding to the frequency fr. In these two modes, the second output of the current control means 4 outputs a trigger signal to the iron loss calculating means 7, respectively, and the input powers P1, P2 and the input current of the permanent magnet type synchronous motor 1 output from the input quantity measuring means 6 are output. I1 and I2 and the input voltages V1 and V2 are taken into the iron loss calculating means 7, respectively.

The iron loss calculating means 7 calculates the input powers P1, P
2, the input currents I1 and I2, the input voltages V1 and V2, and the winding resistance R of the permanent magnet synchronous motor 1 are input, and the iron loss conductance g0 of the permanent magnet synchronous motor 1 is calculated and output. The setting storage means 8 inputs and stores the iron loss conductance g0, and stores the winding resistance R and the iron loss conductance g0.
Is output.

The magnetic flux calculating means 9 receives the input current i, the input voltage v, and the winding resistance R, and inputs the input current i, the input voltage v, and the winding resistance R.
The primary linkage flux vector φ is calculated and output. The iron loss torque calculating means 10 calculates an amount Tg proportional to the product of the square value of the magnitude of the primary linkage flux vector φ output from the magnetic flux calculating means 9 and the iron loss conductance g0 output from the setting storage means 8.
Is output. The iron loss correction means 11 outputs the torque command Tc
And the iron loss torque calculating means 10 output Tg,
By adding Tg to the torque command Tc, a new torque command T
Output r.

The torque control means 3 is provided with the torque command Tr
And outputs a signal in which the output torque of the permanent magnet type synchronous motor 1 follows the torque command Tr. Power converter 2
Inputs the output of the torque control means 3 via the switch 5 and supplies electric power to the permanent magnet type synchronous motor 1.

Here, the basis for solving the above-mentioned problems by the present invention will be described. First, the grounds on which the iron loss conductance g0 can be measured will be described. The relational expression between the input powers P1 and P2 when three different three-phase AC currents flow is represented by the following equation.

[0011]

(Equation 1)

Here, Pc1 and Pc2 are copper losses, Pm1 and Pm2 are mechanical losses, and Pi1 and Pi2 are iron losses.

[0013] The copper loss is expressed as follows, where R is the winding resistance of the permanent magnet type synchronous motor 1.

[0014]

(Equation 2)

## EQU1 ## Further, since the rotational speed of the permanent magnet type synchronous motor 1 is the same as the mechanical loss,

[0016]

(Equation 3) It becomes the relationship.

The iron loss is obtained by using the iron loss conductance g0 of the permanent magnet type synchronous motor 1.

[0018]

(Equation 4)

## EQU1 ## Therefore, from equation (1), (2)
Equations (3), (4), (5), (6), (7)
When the iron loss conductance g0 is obtained using the equation,

[0020]

(Equation 5) Becomes

As described above, two different three-phase AC currents are supplied to the permanent magnet synchronous motor 1 at a predetermined frequency fr, and the winding resistance R, the input powers P1, P2, and the input currents I1, I2 And the input voltages V1 and V2, the iron loss conductance g0 can be calculated.

Second, the output torque control of the permanent magnet type synchronous motor 1 based on the new torque command Tr which is the output of the iron loss correction means 11 will be described. FIG. 2 shows an equivalent circuit block of the permanent magnet synchronous motor 1. A part 12 of the equivalent circuit of the permanent magnet synchronous motor includes a winding resistance R and an iron at each rotation angular frequency ω of the permanent magnet synchronous motor 1. The permanent magnet type synchronous motor 1 excluding the loss conductance g0 '
Represents an equivalent circuit component of Generally, the output torque T of the permanent magnet synchronous motor 1 is expressed by the following equation.

[0023]

(Equation 6)

Here, in the equation, i1 is an input current vector of the permanent magnet synchronous motor 1, i0 is a current vector flowing through the iron loss conductance g0 ', and i1' is a current flowing from the input current vector i1 to the iron loss conductance g0 '. A current vector obtained by subtracting the current vector i0, and x represents a vector product. From equation (9), it can be seen that the torque of the permanent magnet synchronous motor 1 can be controlled by controlling the current vector i1 '. However, the current vector i1
Can be detected, but the current vectors i0 and i1 '
Cannot be directly detected, so that the output torque T according to the torque command Tc cannot be obtained as it is.

Therefore, the torque corresponding to the iron loss conductance g0 'of the second term on the rightmost side of the equation (9) is obtained by calculation. For simplicity, assuming that the iron loss of the permanent magnet type synchronous motor 1 is proportional to the rotation frequency, the iron loss conductance g at each rotation angular frequency ω of the permanent magnet type synchronous motor 1 is given.
0 'is

[0026]

(Equation 7)

Can be expressed as follows. Here, ωr is a rotation angular frequency when the iron loss conductance g0 is measured, and is represented by the following equation.

[0028]

(Equation 8)

Therefore, the current vector i0 flowing through the iron loss conductance g0 'is

[0030]

(Equation 9)

It can be expressed as On the other hand, the primary linkage flux vector φ
Is

[0032]

(Equation 10)

## EQU1 ## Here, v0 is a voltage vector obtained by removing the voltage drop of the winding resistance R from the input voltage vector v1 of the permanent magnet type synchronous motor 1. In the steady state, the primary interlinkage magnetic flux vector φ is given by the following equation (13). The following equation is obtained.

[0034]

[Equation 11] Here, j is an imaginary unit.

When the voltage vector v0 is obtained from the equation (14),

[0036]

(Equation 12)

Is as follows. Therefore, when Equations (10), (12) and (15) are substituted into Equation (9),

[0038]

(Equation 13)

The magnitude of the torque corresponding to the iron loss conductance g0 'of the second term on the right-hand side of the equation (16) is determined by the square value of the magnitude of the primary interlinkage magnetic flux | φ | It can be seen that the value is proportional to the product of the loss conductance g0. In addition, since the output torque of the permanent magnet synchronous motor 1 is controlled by the current vector i1, the torque command Tc is defined as Tg where the torque corresponding to the iron loss conductance g0 'is Tg.
And a new torque command Tr may be obtained.

Here, the reason why the primary flux linkage vector φ of the permanent magnet synchronous motor 1 can be calculated by the magnetic flux calculation means 9 will be described. From the equivalent circuit of the permanent magnet type synchronous motor shown in FIG.
Is

[0041]

[Equation 14]

## EQU4 ## Therefore, the primary interlinkage magnetic flux vector φ can be calculated from the current vector i1 of the input current i, the voltage vector v1 of the input voltage v, and the winding resistance R.

As described above, the amount proportional to the product of the square value of the magnitude | φ | of the primary flux linkage vector of the permanent magnet type synchronous motor 1 and the iron loss conductance g0 is added to the torque command Tc. The output torque T of the permanent magnet synchronous motor 1 can be controlled based on the new torque command Tr.

[0044]

According to the present invention, it is possible to control a permanent magnet type synchronous motor with high accuracy, and furthermore, it is possible to automatically set the electrical constants of the permanent magnet type synchronous motor required for that purpose with high accuracy. Measuring instruments and the like become unnecessary, which is very useful. In the present application, the input amount measuring means is described as being directly measured from a sensor or the like for easy understanding. However, it does not impair the gist of the present application even if the control signal is processed and configured. Not even.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is an equivalent circuit of a permanent magnet type synchronous motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Permanent magnet type synchronous motor 2 Power converter 3 Torque control means 4 Current control means 5 Switch 6 Input amount measuring means 7 Iron loss calculating means 8 Setting storage means 9 Magnetic flux calculating means 10 Iron loss torque calculating means 11 Iron loss correcting means 12. Part of equivalent circuit of permanent magnet type synchronous motor

Claims (2)

[Claims] 1. A control device for a permanent magnet type synchronous motor, comprising: a switch for switching between an output of a torque control means having a torque command input and a first output of a current control means; and using the switch output as a command input to supply electric power to the motor. A power converter for supplying, and input amount measuring means for outputting each value of voltage, current and electric power applied to the electric motor, and an output of the input amount measuring means, a second output of the current control means, The permanent magnet type synchronous motor control device according to claim 1, further comprising an iron loss calculating means having the first output of the setting storage means as an input, and connecting the output of the iron loss calculating means as the setting storage means input. 2. An iron loss torque having a magnetic flux calculating means having the input of the input amount measuring means and the first output of the setting storage means as inputs, and having the output and the second output of the setting storage means as inputs. 2. A permanent magnet type synchronous motor according to claim 1, further comprising a calculating means, wherein an output of the iron loss correcting means having the output and the torque command as inputs is connected to the torque control means as a new torque command input. Control device.