JP2002272196A - Synchronous motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain highly accurate torque control, even if parameters are changed. SOLUTION: This device is provided with a parameter table, in which the rates of change from given values of parameters of a synchronous motor that are changed according to a plurality of state parameters, independently controllable of the synchronous motors are stored according to the values of the state parameters; a state-parameter detector that detects or estimates the state parameters; a parameter corrector that corrects the parameters using the rate of change from the given values of the parameters obtained from the values of the state parameters, by referring to the parameter table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling a synchronous motor, and more particularly to a technique for controlling the output torque of a synchronous motor with high accuracy.

[0002]

2. Description of the Related Art The prior art is shown in FIG. 4 taking an example of a control device of a permanent magnet type synchronous motor having a permanent magnet as a field, and will be described below with reference to FIG. The power converter 1 is a synchronous motor 2
To supply power. The current command converter 3 is a synchronous motor 2
Using the parameters Ldn, Lqn, and φn, current commands id * and iq * are obtained and output so that the output torque of the synchronous motor 2 matches the torque command T *. Here, if the field axis of the synchronous motor 2 is called a d-axis and the torque axis orthogonal thereto is called a q-axis, Ldn is a d-axis inductance reference value of the synchronous motor 2 and Lqn is a q-axis inductance reference value. Where φn is a reference value of the magnetic flux linked to the armature winding by the permanent magnet of the synchronous motor 2. The component converter converts the detected current of the synchronous motor 2 into a d-axis component current i.
The output is divided into d and q-axis component currents iq. The current controller 4 outputs to the power converter 1 a control signal S such that id follows id * and iq follows iq *.

[0003]

The parameters Ldn, Lqn, and φn used in the current command calculator 3 of the prior art are set to predetermined fixed values. However, when a current flows through the synchronous motor 2, the amount of magnetic flux inside the synchronous motor 2 changes, and the parameters fluctuate due to, for example, magnetic saturation inside the synchronous motor 2. That is, it is clear that the parameters change according to the current of the synchronous motor 2. Therefore, the parameters inside the synchronous motor and the parameters Ldn, Lqn,
Since an error occurs between the torque command φn and the torque φn, a problem arises in that a torque according to the torque command T * cannot be output. The present invention has been made to solve the above problems.

[0004]

According to the present invention, there is provided a synchronous motor for controlling a power converter for supplying electric power to a synchronous motor using parameters of the synchronous motor. A parameter table storing, in the control device, a rate of change from a predetermined value of a parameter of the synchronous motor that fluctuates according to a plurality of state variables of the synchronous motor that can be independently controlled in accordance with the value of the state variable; A state variable detector for detecting or estimating the state variable, and a parameter corrector for correcting a parameter by using a rate of change from a predetermined value of the parameter obtained by referring to the parameter table from the value of the state variable. It is characterized by having.

According to a second aspect of the present invention, the plurality of state variables of the synchronous motor are a current component of a field axis of the synchronous motor and a current component of a torque axis orthogonal thereto, and the parameters are the inductance Ld of the field axis and the current component. It is characterized by the torque shaft inductance Lq.

According to a third aspect of the present invention, the plurality of state variables of the synchronous motor are a current component of a field axis of the synchronous motor and a current component of a torque axis orthogonal thereto, and when the field of the synchronous motor is a permanent magnet. The parameter is a magnetic flux φ interlinking the armature winding of the permanent magnet and an inductance Lq of the torque axis.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to claims 1, 2 and 3 are shown in FIGS.
The following will be described with reference to the respective drawings. In FIG. 1, a power converter 1 supplies power to a synchronous motor 2. The state variable detector detects state variables u1 to uj of the synchronous motor 2 such as current and voltage. Parameter table 7 is
The state variables u1-uj are input and the state variables u1-uj are input.
the variation rate Δp of the parameter of the synchronous motor 2 corresponding to uj
1 to Δpk are output. The parameter corrector 9 calculates the fluctuation rates Δp1 to Δpk and the reference values pn1 to pn1 of the parameters.
For example, in p1, p1 = pn1 · (1 + Δp1) is calculated, and corrected parameters p1 to pk are output. The control calculator 6 outputs to the power converter 1 a control signal S such that the output torque of the synchronous motor 2 matches the torque command T * using the parameters p1 to pk.

With the above arrangement, the parameter reference value n1
Ｐpnk is a variation rate Δ depending on the values of the state variables u1ｕuj.
Since the parameters p1 to pk corrected by p1 to Δpk are used, it is possible to make the parameters used in the control calculator 6 coincide with the actual parameters of the synchronous motor 2.
The problems of the prior art can be solved.

In FIG. 2, a power converter 1 supplies power to a synchronous motor 2. The component converter 5 converts the detected current of the synchronous motor 2 into a d-axis component current id and a q-axis component current iq.
And output. The parameter table 7 stores the i
d and iq are input, and the fluctuation rate ΔLd of the d-axis inductance and the fluctuation rate ΔLq of the q-axis inductance of the synchronous motor 2 corresponding to the values of id and iq are output. The parameter corrector 9 receives the fluctuation rates ΔLd, ΔLq and the d-axis inductance and the reference values Ldn, Lqn of the q-axis inductance, and calculates Ld = Ldn · (1 + ΔLd) Lq = Lqn · (1 + ΔLq) The corrected Ld and Lq are output. The current command converter 3 calculates Ld and Lq of the output of the parameter corrector 9.
And φn, the current commands id * and iq * such that the output torque of the synchronous motor 2 matches the torque command T * are obtained and output. The current controller 4 determines that id is id * and iq is i
A control signal S that follows q * is output to power converter 1.

In FIG. 3, a power converter 1 supplies power to a synchronous motor 2. The component converter 5 converts the detected current of the synchronous motor 2 into a d-axis component current id and a q-axis component current iq.
And output. The parameter table 7 stores the i
d and iq are input to output a fluctuation rate Δφ of the magnetic flux of the synchronous motor 2 and a fluctuation rate ΔLq of the q-axis inductance according to the values of id and iq. The parameter corrector 9 receives the fluctuation rates Δφ, ΔLq and the reference values φn, Lqn of the magnetic flux and the q-axis inductance and corrects them by calculating φ = φn · (1 + Δφ) Lq = Lqn · (1 + ΔLq). Φ, Lq. The current command converter 3 outputs φ, Lq and L of the output of the parameter corrector 9.
The output torque of the synchronous motor 2 is calculated using the torque command T
The current commands id * and iq * that match * are obtained and output. The current controller 4 determines that id is id *, iq is iq
A control signal S that follows * is output to the power converter 1.

[0011]

According to the present invention, the parameter of the synchronous motor used for control can be changed to a value corresponding to the value of the state variable, so that the parameter used for control and the actual parameter of the synchronous motor can be matched. This makes it possible to perform high-precision torque control. In the present invention, the output of the parameter table 7 is the parameter variation rate. However, the corrected parameter itself, which is the output of the parameter corrector 9, can be output from the parameter table 7.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment according to claim 1 of the present invention.

FIG. 2 is a block diagram showing an embodiment according to claim 2 of the present invention.

FIG. 3 is a block diagram showing an embodiment according to claim 3 of the present invention.

FIG. 4 is a block diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Power converter 2 ... Synchronous motor 3 ... Current command calculator 4 ... Current controller 5 ... Component converter 6 ... Control calculator 7 ... Parameter table 8. ..State variable detector 9 ... Parameter corrector

Claims (3)

[Claims] 1. A synchronous motor control device for controlling a power converter that supplies power to a synchronous motor using parameters of the synchronous motor, wherein the power converter varies according to a plurality of state variables of the synchronous motor that can be independently controlled. A parameter table storing the rate of change of a parameter of the synchronous motor from a predetermined value in accordance with the value of the state variable; a state variable detector for detecting or estimating the state variable; A parameter corrector for correcting a parameter using a variation rate of a parameter from a predetermined value obtained by referring to the parameter table, and transmitting the parameter corrected by the parameter corrector to a control computing unit. A control device for a synchronous motor characterized by the following. 2. A plurality of state variables of the synchronous motor are defined as a current component of a field axis of the synchronous motor and a current component of a torque axis orthogonal thereto, and the parameters are defined as an inductance Ld of the field axis and a torque component of the torque axis. The control device for a synchronous motor according to claim 1, wherein the inductance is Lq. 3. A plurality of state variables of the synchronous motor are defined as a current component of a field axis of the synchronous motor and a current component of a torque axis orthogonal thereto, and when the field of the synchronous motor is a permanent magnet, the parameters are set. 2. The control device for a synchronous motor according to claim 1, wherein a magnetic flux φ interlinked with the armature winding of the permanent magnet and an inductance Lq of the torque shaft are set.