JP2022119473A - Arithmetic unit, control device of electric motor, arithmetic method, control method and program - Google Patents

Abstract

To enable simply and accurately performing parameter adjustment that is used in field weakening control in an electric motor.SOLUTION: An arithmetic unit comprises: means to acquire a set of values that includes revolution speed at time when the revolution speed is increased while maintaining torque of an electric motor at a predetermined value, a value of q-axis current and a value of d-axis current in an exciting circuit of the electric motor, a command value of q-axis voltage for generating the q-axis current in the exciting circuit, and a command value of d-axis voltage for generating the d-axis current in the exciting circuit; means to acquire a circuit parameter of the exciting circuit by applying a model formula determined by a set of values in a range of the revolution speed, in which the value of the q-axis current is constant, to a theoretical formula, in which the revolution speed of the electric motor, the q-axis current, the d-axis current, the q-axis voltage, the d-axis voltage, and the circuit parameter of the exciting circuit are satisfied; and means to determine a parameter for adjusting a current value of the d-axis current when the electric motor is revolved, on the basis of the acquired circuit parameter.SELECTED DRAWING: Figure 2

Description

The present invention relates to control of electric motors.

In the control of the electric motor, field weakening control is performed in order to improve the torque characteristics in the high speed region. Conventionally, parameters for field-weakening control have been adjusted off-line by measuring motor characteristics. However, there have been cases where appropriate field-weakening adjustment cannot be performed simply by setting field-weakening control parameters based on actual motor constants such as phase resistance, phase inductance, and induced voltage constant. Therefore, there may be cases where parameter adjustment is performed by trial and error. Therefore, for example, when a motor that has not been evaluated in advance is newly connected to the control device, there has been a problem that it is difficult to appropriately execute the field-weakening control.

JP 2020-10433 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique that reduces complicated labor and enables easy and accurate adjustment of parameters used for field-weakening control in an electric motor.

Embodiments according to the present invention are exemplified by the following computing devices. In a first aspect, the computing device comprises:
The rotation speed of the electric motor when the rotation speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotation speed, and the rotation speed of the electric motor A value of the d-axis current in the excitation circuit at the time of speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a d-axis voltage for causing the d-axis current in the excitation circuit means for obtaining a set of values including command values for
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation means for obtaining circuit parameters of the excitation circuit by applying a theoretical formula satisfied by the circuit parameters;
means for determining a parameter for adjusting the current value of the d-axis current when rotating the electric motor based on the acquired circuit parameter.

This arithmetic unit uses a model formula determined by a set of values in the rotational speed range in which the value of the q-axis current is constant, so it is possible to improve the accuracy of the circuit parameters to be obtained. In addition, since this arithmetic unit obtains the circuit parameters based on the set of values obtained from the electric motor, it is possible to obtain the circuit parameters according to the actual situation such as the operating state of the electric motor or the environment in which the electric motor is placed. . Then, this arithmetic unit can determine a parameter for adjusting the appropriate current value of the d-axis current based on the acquired circuit parameters.

In a second aspect, the above theoretical formula may be given by Eq.

(Formula A)
Vd = RId - ωLqIq;
Vq = RIq + ωLdId + ωKemf;
where, Iq is the q-axis current, Id is the d-axis current, Vd is the d-axis voltage, Vq is the q-axis voltage, R is the motor phase resistance, Lq is the motor q-axis inductance corresponding to the magnetic flux caused by the q-axis current, Ld is The motor d-axis inductance corresponding to the magnetic flux due to the d-axis current, Kemf is the induced voltage constant, and ω is the electrical angular velocity corresponding to the rotation speed.

In this case, the control device of the motor obtains a plurality of d-axis current values when the motor torque is maintained at a predetermined value and the rotation speed is increased. It suffices to repeat increasing the number of revolutions a plurality of times. The calculation device may acquire a set of values when the number of revolutions of the motor is increased with such different constant torques from the motor control device or the like.

As in Equation A, the theoretical equation satisfies a linear relationship with the d-axis voltage and the q-axis voltage by the q-axis current and the d-axis current, so the computing device can easily and accurately acquire the circuit parameters.

In a third aspect, the model formula may be further determined by the set of values in the rotational speed range in which the value of the d-axis current is 0, and the theoretical formula may be given by Formula B.

(Formula B)
Vd = -ωLqIq;
Vq = RIq + ωKemf;
Equation B does not depend on the d-axis current, so the computing device can acquire the circuit parameters more easily and accurately.

In a fourth aspect, another embodiment of the invention may be exemplified by the following motor control apparatus. The controller for this motor is
means for outputting a q-axis voltage command value for supplying a q-axis current to an excitation circuit of the electric motor;
means for outputting a d-axis voltage command value for supplying a d-axis current to an excitation circuit of the electric motor;
power supply means for supplying power to the electric motor based on the command value of the q-axis voltage and the command value of the d-axis voltage;
current detection means for detecting a current flowing through an excitation circuit of the electric motor;
speed detection means for detecting the rotation speed of the electric motor;
and an arithmetic device, wherein the arithmetic device is
The rotational speed of the electric motor when the rotational speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotational speed, and the rotation speed A value of the d-axis current in the excitation circuit at the time of speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a d-axis voltage for causing the d-axis current in the excitation circuit means for obtaining a set of values including command values for
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation means for obtaining circuit parameters of the excitation circuit by applying a theoretical formula satisfied by the circuit parameters;
means for determining a parameter for adjusting the current value of the d-axis current when rotating the electric motor based on the acquired circuit parameter.

This control device can easily and accurately acquire the circuit parameters of the excitation circuit of the electric motor in the same manner as the arithmetic device. In addition, since this control device obtains circuit parameters based on the set of values obtained from the electric motor, it is possible to obtain circuit parameters in line with actual conditions such as the operating state of the electric motor or the environment in which the electric motor is placed. . Then, this control device can determine parameters for adjusting the appropriate current value of the d-axis current based on the acquired circuit parameters.

In a fifth aspect, the control device is configured such that a combined value obtained by synthesizing the command value of the q-axis voltage and the command value of the d-axis voltage according to the phase difference between the q-axis voltage and the d-axis voltage is the electric power. It may further include means for controlling the d-axis current to flow when a predetermined condition is satisfied for the voltage that can be supplied from the supply means. Here, this predetermined condition can also be said to be a voltage saturation condition. The voltage saturation may be that the combined value reaches the maximum voltage that can be supplied to the electric motor, for example, the maximum DC voltage that is supplied to a power converter such as an inverter. Therefore, the control device may control the d-axis current to flow when the combined value reaches the maximum voltage that can be supplied to the motor. Since there is a limit to the maximum value of the current that can be supplied to the excitation circuit depending on the motor, the control device causes the d-axis current to flow only when the above-mentioned predetermined conditions are satisfied. It is possible to suppress the current and increase the value of the q-axis current that contributes to the torque.

In a sixth aspect, the control device changes at least one of the obtained circuit parameter value and the suppliable voltage value of the power supply means by a compensation coefficient when the d-axis current is caused to flow. means for reducing the current value of the d-axis current by a predetermined limit. When the d-axis current is caused to flow, the control device reduces the current value of the d-axis current within a predetermined limit, thereby smoothly transitioning from a state in which the d-axis current does not flow to a state in which the d-axis current flows. can be transitioned.

In a seventh aspect, the control device is configured such that a combined value obtained by synthesizing the command value of the q-axis voltage and the command value of the d-axis voltage according to the phase difference between the q-axis voltage and the d-axis voltage is the electric power. It may further include means for adjusting the current value of the d-axis current according to the extent to which a predetermined condition is satisfied with respect to the supplyable voltage of the supply means. For example, the control device adjusts the current value of the d-axis current according to the frequency at which the combined value has been saturated with respect to the supplyable voltage of the power supply means in the past or the degree of saturation with respect to the supplyable voltage. A value of d-axis current can be passed through the excitation circuit of the motor.

In an eighth aspect, embodiments of the invention may be exemplified by a computer-implemented method of computation. Here, the computer may be incorporated inside the control device of the electric motor. Further, the computer may be an information processing device capable of cooperating with the motor control device via a network, a storage medium, or the like. With such a calculation method, the computer exhibits the same effect as the above calculation device.

In a ninth aspect, embodiments of the invention may be exemplified by a control method performed by a controller. That is, in this aspect, embodiments of the invention are defined by procedures that are not necessarily limited to controller hardware.

In a tenth aspect, embodiments of the present invention may be exemplified by a program for causing a computer to execute processing. Such programs can be distributed through networks, storage media, or the like. A computer in which such a program is installed operates in the same manner as the arithmetic device and exhibits the same effects.

According to at least one aspect of the present embodiment, complicated labor is reduced, and parameter adjustment used for field-weakening control in an electric motor can be easily and precisely adjusted.

FIG. 1 is a diagram illustrating an example of an application scene of a control device according to Embodiment 1. FIG. FIG. 2 is a diagram illustrating the control device of the first embodiment. FIG. 3 is a diagram exemplifying a processing result by the servo system of the comparative example. FIG. 4 is an overall flow chart of how a control device or a computer associated with the control device coordinates each part of the control device. FIG. 5 is a diagram illustrating a method of identifying circuit parameters by driving a motor. FIG. 6 is a graph of example data recorded when the motor is accelerated at constant torque. FIG. 7 is a diagram illustrating the process of deriving the equation of the regression model. FIG. 8 is a diagram comparing the current adjusted by the identified circuit parameters with the current under control of the comparative example. FIG. 9 is a diagram illustrating the control device of the second embodiment. FIG. 10 is a diagram illustrating the processing of the current command calculator of the control device according to the second embodiment. FIG. 11 is a diagram illustrating a circuit configuration for correcting the current state input to the current command calculator according to the feedback signal from the voltage limiter. FIG. 12 is a diagram illustrating the configuration of a computer.

Hereinafter, an embodiment (hereinafter also referred to as "this embodiment") according to one aspect of the present invention will be described with reference to the drawings. However, this embodiment described below is merely an example of the present invention in every respect. It goes without saying that various modifications and variations can be made without departing from the scope of the invention. That is, in carrying out the present invention, a specific configuration according to the present embodiment may be employed as appropriate. Data appearing in the present embodiment are explained in natural language. More specifically, however, the data appearing in this embodiment are processed in computer-recognizable pseudo-language, commands, parameters, machine language, and the like. In addition, these data are saved in the form of binary data, character strings, or the like in the memory area of the main memory or secondary memory.

<Application example>
First, an example of a scene to which the present invention is applied will be described with reference to FIG. FIG. 1 illustrates a system to which a control device 10 according to this embodiment is applied. However, as shown in FIG. 1, in addition to the controller 10, this system also exemplifies a servomotor (hereinafter simply referred to as a motor) 30 and a position detector 32. FIG. As shown in FIG. 1 , a control device 10 according to this embodiment is a device for controlling a motor 30 . However, the control device 10 can calculate the circuit parameters of the motor 30 and perform appropriate field-weakening correction (FIG. 2) based on the calculated circuit parameters.

First, the motor control function of the control device 10 will be described. As illustrated in FIG. 1, controller 10, when controlling motor 30, is exemplified by position controller 11, speed controller 12, current controller 13, inverter 14, current detector 15 and speed detector 16. It operates as a device with each part to be performed. Each part shown in FIG. 1 is a unit that operates as follows.

The position controller 11 receives a position command (P_ref) input from a host device (not shown) such as a Programmable Logic Controller (PLC) and the position detector 3 attached to the motor 30.
2 to calculate the deviation (position deviation) from the position of the motor 30 detected by 2 (hereinafter referred to as the detected position (P_act)). The position controller 11 calculates the velocity command (V_ref) by multiplying the calculated deviation of the position by the position proportional gain. The speed detector 16 calculates a speed (hereinafter referred to as detected speed (V_act)) by time-differentiating the detected position (P_act). speed detector 16
is an example of speed detection means.

The speed controller 12 multiplies the integral of the deviation between the speed command (V_ref) calculated by the position controller 11 and the detected speed (V_act) by the speed integral gain, and the sum of the calculation result and the speed deviation is proportional to the speed. A torque command (τ_ref) is calculated by multiplying by a gain.

The current controller 13 generates a current command value based on the torque command (τ_ref) calculated by the speed controller 12 and the detected speed (V_act) detected by the speed detector 16 . Then, the current controller 13 generates a voltage command according to the deviation between the current command value and the magnitude of the current actually flowing through the motor 30 detected by the current detector 15 (hereinafter referred to as the detected current). , to the inverter 14 . A PI controller is normally used as the current controller 13 .

The inverter 14 is a unit that amplifies the voltage command from the current controller 13 and applies it to the motor 30 . Inverter 14 is also called a power converter.

The motor 30 is called a servomotor as mentioned above. Various types of motors can be exemplified as the motor 30 . The motor 30 is called an AC synchronous motor, for example, and can be exemplified by a Permanent Magnet (PM) motor having a permanent magnet in its rotor. Examples of PM motors include Surface Permanent Magnet Synchronous Motors (SPMSM) and Interior Permanent Magnet Synchronous Motors (IPMSM). However, the AC synchronous motor is not limited to a PM motor, and may be, for example, a reluctance motor that uses only reluctance torque without using permanent magnets. Examples of reluctance motors include switched reluctance motors (SRM) and synchronous reluctance motors (SynRM).

The position detector 32 is a sensor that informs the controller 10 of the rotation angle of the motor 30 . The position detector 32 is also called a rotary encoder.

Weakening field correction is a technique for reducing the induced voltage generated in the excitation circuit (also referred to as the armature winding) of the motor 30 as the motor 30 rotates.

That is, when the motor 30 rotates at a high speed, an induced voltage proportional to the number of revolutions is generated in a direction in which the current is less likely to flow. Therefore, the control device 10 cannot apply a current to the motor 30 unless a higher voltage is applied to the motor 30 . One of the techniques for mitigating the influence of this induced voltage is called field-weakening control. By the way, field-weakening control cannot always be simply executed.

For example, in the case of a Surface Permanent Magnet (SPM) motor, the currents for driving the motor 30 are the d-axis current Id that contributes to the magnetic flux of the rotor in the magnetic pole direction and the q-axis current Iq that contributes to the magnetic flux orthogonal to the magnetic flux in the magnetic pole direction. can be divided into The controller 10 normally applies a current corresponding to the torque to be output to the q-axis current Iq, and controls the d-axis current Id to zero. In the case of the SPM motor, the current applied to the d-axis current Id does not contribute to torque generation. In the field-weakening control, the control device 10 intentionally causes the d-axis current Id to flow to alleviate the influence of the induced voltage. However, the field-weakening control is affected by the circuit parameters of the motor 30, and the circuit parameters of the motor 30 may fluctuate under the influence of the operating state of the motor 30 or the environment in which the motor 30 is placed. Therefore, the control device 10 of the present embodiment accurately specifies the circuit parameters of the motor 30 in a timely manner when necessary, and executes appropriate field weakening control.

In FIG. 1, at least a part of each part such as the position controller 11, the speed controller 12, the current controller 13, the current detector 15, the speed detector 16, the position detector 32, etc. It may be provided by a main storage device such as a Unit (CPU) and memory. That is, one or more CPUs execute a computer program developed on a memory to control position controller 11, speed controller 12, current controller 13, current detector 15, speed detector 16, and position detector 32. You may perform the process as each part or any one part, such as. Such a CPU and memory are the same as the CPU 101 and the main storage section 102 illustrated in FIG. 10 of the second embodiment. Details of the CPU 101 and the main storage unit 102 will be described separately with reference to FIG.

At least a portion of any one of the position controller 11, speed controller 12, current controller 13, current detector 15, speed detector 16, position detector 32, etc. is an integrated circuit (IC) or other digital It may be a circuit or may include an analog circuit. Integrated circuits include LSIs, Application Specific Integrated Circuits (ASICs), and Programmable Logic Devices (PLDs). PLDs include, for example, Field-Programmable Gate Arrays (FPGAs). Each of the above units may be a combination of a processor and an integrated circuit. The combination is called, for example, a microcontroller (MCU), SoC (System-on-a-chip), system LSI, chipset, or the like.

<Embodiment 1>
Hereinafter, the control device 10 of this embodiment will be described with reference to FIGS. 2 to 8. FIG.

(Constitution)
FIG. 2 is a diagram illustrating the control device 10 of this embodiment. In FIG. 2, details of the current controller 13 of FIG. 1 are illustrated. As shown in FIG. 2, the current controller 13 of this embodiment includes a current command calculator 131, a d-axis current controller 132, a q-axis current controller 133, a voltage coordinate converter 134, a PWM calculator 135, a current coordinate converter It has a vessel 136 .

The current command calculator 131 receives a torque command (τ_ref) and generates a d-axis current command value (Id_ref) after field weakening correction and a q-axis current command value (Iq_ref) corresponding to the torque. The generated d-axis current command value is input to a differencer (adder) that calculates the difference between the d-axis current command value (Id_ref) and the d-axis current current value (Id). The differentiator calculates a difference value from the d-axis current command value and the current value (Id) of the d-axis current output from the current coordinate converter 136 . The calculated difference value is input to the d-axis current controller 132 . Based on the difference between the d-axis current command value (Id_ref) and the d-axis current current value (Id), the d-axis current controller 132 applies a d-axis current to reduce or eliminate the difference. A d-axis voltage (Vd) for is calculated and input to the voltage coordinate converter 134 . The d-axis current controller 132 is an example of means for outputting a d-axis voltage command value for supplying a d-axis current to the excitation circuit of the motor.

The generated q-axis current command value (Iq_ref) is input to a difference calculator (adder) that calculates the difference between the q-axis current command value (Iq_ref) and the q-axis current current value (Iq). be done. The differentiator is
A difference value between the command value (Iq_ref) of the q-axis current and the current value (Iq) of the q-axis current output from the current coordinate converter 136 is calculated. The calculated difference value is input to the q-axis current controller 133 .
Based on the difference between the command value (Iq_ref) of the q-axis current and the current value (Iq) of the q-axis current, the q-axis current controller 133 applies a q-axis current to reduce or eliminate the difference. A q-axis voltage (Vq) for is calculated and input to the voltage coordinate converter 134 . The q-axis current controller 133 is an example of means for outputting a q-axis voltage command value for supplying a q-axis current to the excitation circuit of the motor.

The voltage coordinate converter 134 calculates command values (Vu, Vv, Vw) for each phase of the three-phase alternating current from the d-axis voltage (Vd) and the q-axis voltage (Vq), and inputs them to the PWM calculation unit 135. do. PWM calculator 13
5 is based on the ratio of the voltage command values (Vu, Vv, Vw) of each phase to the DC maximum voltage (Vpn),
A duty ratio in pulse width modulation (PWM) is calculated, and an on/off signal based on the calculated duty ratio is input to the inverter 14 . The inverter 14 generates an AC voltage for each phase according to the input on/off signal to drive the motor 30 . The voltage coordinate converter 134, the PWM calculator 135, and the inverter 14 are an example of power supply means for supplying power to the motor based on the command value of the q-axis voltage and the command value of the d-axis voltage.

A current coordinate converter 136 converts the three-phase currents (Iu, Iv, Iw) of the excitation circuit of the motor 30 detected by the current detector 15 into a d-axis current Id and a q-axis current Iq. The current detector 15 and the current coordinate converter 136 are examples of current detection means.

(Processing result of comparative example)
FIG. 3 illustrates the results of processing by the servo system of the comparative example. The servo system of the comparative example is a system that does not consider the influence of the operating state of the motor or the environment in which the motor is placed. For example, the comparative example is a system that executes field-weakening control while fixing the circuit parameters of the motor.

In FIG. 3, the horizontal axis represents the rotational speed of the motor, and the vertical axis represents the current and voltage at that rotational speed. In FIG. 3, the upper part shows the measured values of the current, and the lower part shows the command values of the voltage. Examples of currents include a d-axis current (Id), a q-axis current (Iq), and their combined value (|I|=((Id) ² +(Iq) ² ) ^1/2 ). As voltages, d-axis voltage (Vd), q-axis voltage (Vq), and their combined value (|V|=((Vd) ² +(Vq) ² ) ^1/2 ) are exemplified. .

Further, in FIG. 3, the rotation speed on the horizontal axis is divided into three sections A, B, and C. As shown in FIG. Section A is a section in which the d-axis current is 0 and a section in which the maximum q-axis current can flow. In the sections B and C, the voltage required for the q-axis is reduced by allowing the d-axis current to flow. This is field weakening control. However, in section C, the maximum current cannot flow due to voltage limitation. The voltage limit is determined by the maximum DC voltage (Vpn) applied to the inverter that drives the motor. This is because the system cannot use a voltage higher than the maximum DC voltage (Vpn). Furthermore, in regions B and C, the amount of current that can be applied to the q-axis is reduced by the amount of the d-axis current that is applied. That is, the maximum torque is lowered.

As described above, the servo system of the comparative example cannot determine an appropriate d-axis current because the field-weakening control is executed while the circuit parameters of the motor are fixed. In this embodiment, the circuit parameters of the motor 30 are determined flexibly and timely with good precision according to the physical characteristics of the motor, the operating state of the motor, the operating environment, etc., and appropriate field-weakening control is performed. Run. As a result, the control device 10 of the present embodiment can extend the section A (the section in which the d-axis current is 0) in the high-speed rotation direction as compared with the servo system of the comparative example. again,
Even when the d-axis current is applied, the d-axis current value (Id) is set to an appropriate value, and the q-axis current is set to a value as large as possible to suppress the decrease in maximum torque compared to the servo system of the comparative example. do.

(process)
The processing of the control device of this embodiment will be exemplified below. FIG. 4 is an overall flow chart for adjusting each part of the control device 10 by the control device 10 or a computer that cooperates with the control device 10 . The processing in FIG. 4 is automatic adjustment processing by the control device 10, and is processing executed by the CPU according to a computer program, for example. The process of FIG. 4 is also exemplified as a process in which the CPU of control device 10 or a computer that cooperates with control device 10 through a network sequentially instructs the user who adjusts control device 10 and motor 30 to make adjustments. In the following description, it is assumed that the control device 10 executes the processing of FIG.
In this embodiment, the controller 10 first identifies the circuit parameters of the motor 30, such as the motor phase resistance R and the motor phase inductance L (S1). Here, for example, the motor phase resistance R, the motor phase inductance L, and the like are directly measured by measuring instruments. Also, as these values, motor maker nominal values (specification values) may be used. Therefore, in the process of S1, the control device 10 may receive an input such as a measured value by a measuring instrument or a motor manufacturer's nominal value (specification value). Controller 10 may also receive these circuit parameters from other computers on the network. The control device 10 executes the following control based on the motor phase resistance R, the motor phase inductance L, etc. identified in the process of S1.

Next, the control device 10 adjusts the current controller 13 (S2). For example, controller 10 determines the gain of current controller 13 . More specifically, in the d-axis current controller 132, the controller 10 calculates the d-axis voltage (Vd) from the difference between the d-axis current command value (Id_ref) and the d-axis current current value (Id). Determines the coefficient when calculating. Further, the control device 10 uses the q-axis current controller 133 to calculate the q-axis voltage (Vq) from the difference between the command value (Iq_ref) of the q-axis current and the current value (Iq) of the q-axis current. Set coefficient. These coefficients may be empirical values or experimentally determined values.

Next, the control device 10 adjusts the speed controller 12 and the position controller 11 (S3). More specifically, the controller 10 adjusts the velocity loop proportional gain, the velocity loop integral time constant, the position loop proportional gain, and the like. However, if the torque control is used to adjust the parameters of the field-weakening control, this step can be skipped. The control device 10 gradually changes the proportional gain of the speed loop to a larger value within a range in which the motor speed does not vibrate, and sets it to an appropriate value, thereby achieving fast control with good response. In addition, the control device 10 gradually reduces the integral time constant of the speed loop within a range in which motor speed oscillation does not occur, and sets it to an appropriate value, thereby realizing fast control with good response.

The controller 10 adjusts the position loop after completing the adjustment of the velocity loop. The control device 10 can increase the responsiveness by gradually increasing the gain within a range in which the rotational speed of the motor does not overshoot or undershoot, and setting the gain to an appropriate value.

Next, the control device 10 identifies the circuit parameters of the motor 30 by driving the motor 30 before adjusting the parameters of the field-weakening control (S4). A method for identifying circuit parameters in Embodiment 1 is illustrated in FIG.
Next, the controller 10 adjusts the field-weakening control parameters based on the circuit parameters identified in the process of S4 (S5). For example, the control device 10 determines the d-axis current Id when executing the field weakening control in accordance with the motor rotation speed. Various methods have already been proposed for determining field-weakening parameters and controlling motors by field-weakening (for example, Shigeo Morimoto et al., "Wide range variable speed operation using flux-weakening control for PM motors", The Institute of Electrical Engineers of Japan). 112, No. 3, P.292-P.298, The Institute of Electrical Engineers of Japan, March 20, 1992). Therefore, in this embodiment, the details of the method for adjusting the field-weakening parameter based on the identified circuit parameter are omitted.

FIG. 5 is a diagram illustrating a method of identifying circuit parameters of the motor 30 by driving the motor 30 (details of S4 in FIG. 4). In this process, the control device 10 accelerates the motor 30 with a constant torque (that is, a constant q-axis current Iq) (S11). Then, in the acceleration state of S11, the control device 10 records time-series data of the motor rotation speed, the d-axis actual current, the q-axis actual current, the d-axis voltage command value, and the q-axis voltage command value (S12). .

The processing of S11 by the control device 10 is an example of processing in which the torque of the electric motor is maintained at a predetermined value and the rotation speed is increased. The processing of S12 is an example of obtaining a set of values. Therefore, the control device 10 executes the process of S12 as an example of means for acquiring a set of values.

Here, the motor rotation speed is an example of the rotation speed of the electric motor. Also, the q-axis actual current acquired in S12 is an example of the value of the q-axis current in the excitation circuit of the motor when the motor is at the above rotational speed. Also, the d-axis actual current acquired in S12 is an example of the value of the d-axis current in the excitation circuit when the motor is at the rotational speed. Furthermore, the command value of the q-axis voltage acquired in S12 is an example of the command value of the q-axis voltage for causing the q-axis current in the excitation circuit. Furthermore, the command value of the d-axis voltage acquired in S12 is an example of the command value of the d-axis voltage for causing the d-axis current to occur in the excitation circuit.

FIG. 6 is a graph of example data recorded when the motor 30 is accelerated at constant torque (constant q-axis current Iq). Examples of this data include motor rotation speed, d-axis actual current (Id), q-axis actual current (Iq), d-axis voltage command value (Vd), and q-axis voltage command value (Vq). In FIG. 6, the uppermost graph G1 exemplifies the data of the motor rotation speed with time on the horizontal axis. A middle graph G2 illustrates data of the d-axis actual current (Id) and the q-axis actual current (Iq) with time as the horizontal axis. Graph G3 at the bottom illustrates data of the command value (Vd) for the d-axis voltage and the command value (Vq) for the q-axis voltage, with time on the horizontal axis. As is clear from the middle graph G2, when the motor 30 is accelerated with a constant torque, the q-axis actual current (Iq) is of course a constant value. At this time, the control device 10 controls the d-axis actual current (Id) to 0 until the motor rotation speed reaches a predetermined value (the interval until the time exceeds 0.04 seconds in FIG. 6).

Then, when the motor rotation speed reaches a predetermined value, the control device 10 causes the d-axis actual current (Id) to flow in a direction that cancels out the induced voltage generated in the excitation circuit (stator winding) of the motor. Note that the maximum value of the voltage vector norm |V|=(Vd ² +Vq ² ) ^1/2 is restricted by the power supply voltage of inverter 14 (also referred to as maximum DC voltage Vpn). Also, the maximum value of the current vector norm |I|=(Id ² +Iq ² ) ^1/2 is constrained by the specifications of the motor 30 .

Next, the control device 10 determines a section in which the q-axis actual current is constant and the d-axis actual current is 0 among the time-series data recorded in the process of S12, and extracts data belonging to the section (S13).

Here, in an alternating current (AC) synchronous motor, the d-axis actual current (Id), q-axis actual current (Iq), d-axis voltage (Vd), and q-axis voltage (Vq) are calculated using the following theoretical formula (voltage equation) meet.

(Formula 1)
Vd = (R + sLd) Id - ωLqIq;
Vq = (R + sLq)Iq + ωLdId + ωKemf;
where, Vd: d-axis voltage, Vq: q-axis voltage, Id: d-axis current, Iq: q-axis current, R: motor phase resistance, s: differential operator, Ld: motor d-axis inductance, Lq: motor q Shaft inductance, Kemf: induced voltage constant, ω: electrical angular velocity corresponding to motor rotation speed.

Assuming that Id=0 and Iq=constant, the differential value of Iq is 0, so Equation 1 above becomes Equation 2 below.

(Formula 2)
Vd = -ωLqIq;
Vq = RIq + ωKemf;
Therefore, the control device 10 derives a regression model equation from the data in the section where the q-axis current is constant and the d-axis current is 0, using the method of least squares or the like.

FIG. 7 is a diagram illustrating the process of deriving the equation of the regression model. The data of the graphs G4 and G5 are the data of the d-axis actual current and the q-axis actual current of the graph G2 illustrated in FIG. The horizontal axis is drawn as the number of motor revolutions (speed [r/min]). As in Equation 2 above, the d-axis voltage and the q-axis voltage change linearly with time in the section where the d-axis current is 0 and the q-axis current is constant. Therefore, the control device 10 regards the command value of the q-axis voltage as the q-axis voltage, and derives a regression model equation by the method of least squares or the like (S141). Further, the control device 10 regards the command value of the d-axis voltage as the d-axis voltage, and derives a regression model equation by the method of least squares or the like (S142). Then, the controller 10 makes the obtained equations of Vd and Vq based on the regression model correspond to the above Equation 2, and obtains the motor q-axis inductance Lq, the motor phase resistance R, and the induced voltage constant Kemf.

Although it depends on the type of the motor 30, if the motor 30 has a type in which Lq and Ld have the same value, Lq=Ld is obtained. On the other hand, when Ld and Lq are different in the motor 30, Id is changed instead of Id=0 and the measurement is performed again. In this case, the following formula 3 is obtained from formula 1.

(Formula 3)
Vd = RId - ωLqIq;
Vq = RIq + ωLdId + ωKemf;
Therefore, the control device 10 obtains a model formula by performing the method of least squares or the like on the measurement results of Vq, Iq, and Id with Id changed. Then, the control device 10 can obtain Ld from the correspondence relationship between the obtained model formula and the above formula (3).

As described above, the control device 10 has a regression model formula in which the horizontal axis is the motor rotation speed and the vertical axis is the command value of the d-axis voltage in the above interval, and the horizontal axis is the motor rotation speed and the vertical axis is the command value in the same interval. Generate a regression model equation for the command value of the q-axis voltage. and a theoretical expression satisfied by the motor rotation speed and the d-axis voltage (and the q-axis current) of the motor 30, and the motor rotation speed and the q-axis voltage (and the q-axis current, and possibly the d-axis current) of the motor 30 The formulas of the two generated regression models are applied to the theoretical formula that satisfies and . Then, the equations of the respective regression models are associated with the theoretical equations, and from the relationship between the motor rotation speed and the voltage, the circuit parameters used for adjusting the field-weakening control are identified (S14). The processing of S14 is an example of acquiring the circuit parameters of the excitation circuit. Therefore, the control device 10 executes the process of S14 as an example of means for acquiring the circuit parameters of the excitation circuit. Equations 1 to 3 are examples of theoretical equations satisfied by the rotation speed of the motor, the q-axis current, the d-axis current, the q-axis voltage, the d-axis voltage, and the circuit parameters of the excitation circuit.

Finally, the control device 10 reflects the identified circuit parameters in the adjustment of field-weakening control (S15). For example, the control device 10 stores the identified circuit parameter at a predetermined address of memory that is referred to during field-weakening control. These parameters are referred to in the process of S5 in FIG. 4 and used when adjusting the field-weakening control. The processing of S5 reflecting the result of S14 is an example of determining a parameter for adjusting the current value of the d-axis current. Therefore, the control device 10 executes the processes of S15 and S5 as an example of means for determining parameters for adjusting the current value of the d-axis current.

FIG. 8 is a diagram comparing the current adjusted by the identified circuit parameters with the current under control of the comparative example. The upper graph G6 in FIG. 8 illustrates the q-axis actual current Iq1 when adjusted by the identified circuit parameters and the q-axis actual current Iq0 before adjustment. Graph G7 in the lower part of the same figure illustrates the d-axis actual current Id1 when adjusted by the identified circuit parameters and the d-axis actual current Id0 before adjustment. In FIG. 8, the horizontal axis is the motor rotation speed (speed in FIG. 8, unit [r/min]).

(Effect of Embodiment)
In the state before adjustment (comparative example) in FIG. 8, the d-axis actual current Id0 flows from the vicinity of 3000 [r/min] on the horizontal axis. On the other hand, in the state after adjustment by the control device 10 of the present embodiment, the d-axis actual current Id1 flows from around 4000 [r/min]. In this manner, the control device 10 can measure the circuit parameters of the excitation circuit of the motor 30 according to the operating state or environment of the motor 30, and perform field-weakening control in a preferable state. According to the control device 10, the circuit parameters of the excitation circuit of the motor 30 can be measured without complicated labor such as trial and error even in an environment where there is no sophisticated measuring instrument. By appropriately executing the field-weakening control, the control device 10 can flow a larger q-axis current, and the performance of the motor 30 can be exhibited. Therefore, for example, even when a motor that has not been evaluated in advance is newly connected to the control device 10, the control device 10 can perform appropriate field-weakening control.

As described above, the control device 10, as shown in Equation 2 or Equation 3, linearly The circuit parameters of the excitation circuit of the motor 30 can be obtained with high accuracy from the model formula. Further, in the motor 30 having the same motor d-axis inductance Ld and motor q-axis inductance Lq, the control device 10 accurately determines the circuit parameters of the excitation circuit of the motor 30 from a simple straight line without the d-axis current Id as shown in Equation 2. can be obtained.

Then, the control device 10 can determine the d-axis current Id according to the motor rotation speed in accordance with the obtained circuit parameters of the excitation circuit of the motor 30, and execute field weakening control.

<Embodiment 2>
The control device 10A of the second embodiment will be described below with reference to FIGS. 9 and 10. FIG. FIG. 9 is a diagram illustrating the control device 10A of the second embodiment. The control device 10A has a configuration in which a voltage limiter 137 is added to the control device 10 of the first embodiment. The voltage limiter 137 limits the combined value V (norm |V|) of the d-axis voltage command value Vd and the q-axis voltage command value Vq to the power supply voltage (maximum DC voltage) Vpn of the inverter 14 . The voltage limiter 137 is implemented by, for example, a computing device capable of numerical computation. For example, the voltage limiter 137 sets Vd and Vq at the same ratio so that the norm |V| is equal to or less than the limit value while maintaining the ratio between the command value Vd for the d-axis voltage and the command value Vq for the q-axis voltage. It is sufficient to calculate so as to decrease it. Here, the composite value V (norm |V|) is a composite obtained by combining the command value of the first voltage and the command value of the second voltage according to the phase difference between the first voltage and the second voltage. An example value.

In FIG. 9, in the voltage limiter 137, information as to whether or not the voltage limit is operating is input to the current command calculator 131 by means of the feedback signal FD. Whether or not the voltage limit is operating is determined by the fact that the combined value V reaches the maximum DC voltage Vpn in the voltage limiter 137.
It can be determined by whether or not a transistor, a diode, or the like is turned on. It should be noted that the voltage limiter 137 detects when the combined value V approaches the maximum DC voltage Vpn within a predetermined limit (hereinafter referred to as saturation).
may be detected and the voltage limited. Therefore, the voltage limiter 137 may notify the degree of saturation of the combined value V. FIG. The degree of saturation is determined by the maximum DC voltage Vpn
may be the frequency of occurrence of a phenomenon approaching within a predetermined limit (the number of occurrences per unit time).

In the present embodiment, the current command calculator 131 operates until the voltage limiter 137 operates to limit the voltage, that is, when the combined value V does not reach the maximum DC voltage Vpn, the current command calculator 131 Do not perform field-weakening control. This is because the inverter 14 can overcome the induced electromotive force and supply power to the excitation circuit of the motor 30 when the combined value V does not reach the maximum DC voltage Vpn. In this state, the control device 10A (current command calculator 131) does not execute field weakening control and maintains the d-axis current at zero. Therefore, the control device 10A can supply almost all power as q-axis current that produces torque. The voltage limiter 137 is an example of means for determining whether or not the combined value satisfies a predetermined condition with respect to the suppliable voltage of the power supply means.

FIG. 10 illustrates processing of the current command calculator 131 of the control device 10A in the second embodiment. In this process, the current command calculator 131 acquires the degree of voltage saturation in the voltage limiter 137 (S41).

Then, the current command calculator 131 determines whether or not the degree of voltage saturation exceeds a predetermined limit (S42). Here, the current command calculator 131 may use the feedback signal from the voltage limiter 137 as it is to determine the degree of voltage saturation. Further, the current command calculator 131 may process the feedback signal from the voltage limiter 137 to determine the degree of voltage saturation. For example, according to the feedback signal from the voltage limiter 137, the current command calculator 131, in S42, when voltage saturation occurs at a predetermined frequency, or when voltage saturation continues for a predetermined period of time, It may be determined that the degree of voltage saturation exceeds a predetermined limit.

In S42, if it is determined that the degree of voltage saturation exceeds the predetermined limit, the current command calculator 131 sets field weakening parameters. In this case, the current command calculator 131 sets, for example, a d-axis current command value that weakens the induced electromotive force of the excitation circuit of the motor 30, and the controller 10A controls the d-axis current to flow.

On the other hand, if it is determined that the degree of voltage saturation does not exceed the predetermined limit, the current command calculator 131 does not set the field weakening parameter. In this case, the command value of the d-axis current is maintained at zero. Such processing of S41 and S42 by the control device 10 is an example of suppressing the d-axis current until the combined value satisfies a predetermined condition for the suppliable voltage of the power supply means. On the other hand, the current command calculator 131 sets the field weakening parameter only when it is determined that the degree of voltage saturation exceeds the predetermined limit. Therefore, the processing of S42 and S43 can be said to be an example of means for controlling the d-axis current to flow when the combined value satisfies a predetermined condition with respect to the suppliable voltage of the power supply means.

With such a configuration, the control device 10A does not perform field-weakening control when voltage saturation does not reach a predetermined limit, maintains the d-axis current at 0, and reduces the q-axis current that contributes to the torque of the motor 30. power can be supplied to the motor 30 by concentrating on That is, the control device 10A activates the field-weakening control only when necessary and causes the d-axis current to flow. Therefore, the field-weakening control is adjusted so that the area of section A in FIG. 3 of the first embodiment can be made as large as possible. be able to.

For example, even when the control device 10 obtains the circuit parameters of the excitation circuit of the motor 30 and executes the field-weakening control as in the first embodiment, the environment (such as temperature) in which the control device 10 or the motor 30 is installed, the control device 10 Alternatively, the voltage command value may not be saturated depending on the operating state of the motor 30 or the like. Conversely, even though the voltage command value is saturated, the field-weakening control may not be performed. The control device 10A of the second embodiment can accurately execute field-weakening control when field-weakening control is required.

(Compensation that suppresses field-weakening control)
Furthermore, by performing the following additional settings, it is possible to smoothly switch the amount of compensation given by the field-weakening control when the field-weakening control is enabled/disabled. For example, a parameter is set to a state in which the field-weakening control is less likely to work than the parameter measured by the control device 10A. Specifically, the control device 10A does not use the circuit parameters (for example, the motor phase resistance R, the motor phase inductance L, the induced voltage constant Kemf, etc.) identified in the procedure of the first embodiment as they are for field weakening control. Multiply the circuit parameters by the compensation factor. In theory, the control device 10A should be set so that the voltage required for the current to flow is reduced by this compensation coefficient. The control device 10A may multiply any one circuit parameter or a plurality of parameters by a compensation coefficient. The controller 10A multiplies the circuit parameters (for example, the motor phase resistance R, the motor phase inductance L, the induced voltage constant Kemf, etc.) by the compensation coefficients to obtain the obtained circuit parameter values and the suppliable voltage values of the power supply means. is an example of changing at least one of by a compensation coefficient. Therefore, the control device 10 is also an example of means for reducing the current value of the d-axis current within a predetermined limit.

For example, in the case of the motor phase resistance R, applying a compensation coefficient smaller than 1 theoretically reduces the voltage required for current flow. In other words, the theoretical voltage saturation determined from the state of the motor is less likely to occur, and the field-weakening control is less likely to work. The control device 10 makes the field-weakening control difficult to work when executing the field-weakening control, thereby smoothing the transition from the state where the field-weakening control does not work to the state where the field-weakening control works.

(Circuit that promotes field-weakening control)
The feedback signal from the voltage limiting section 137 may be a value indicating the degree of voltage saturation, for example, the rate of time during which voltage limitation occurs in the voltage limiting section 137 within a certain period of time, or the frequency of occurrence. . The current input value (for example, the command torque τref to the current command calculator 131, the motor rotation speed v, the PN voltage VPN
etc.) may be provided with a correction circuit for correcting so that field-weakening control is required.

FIG. 11 illustrates a circuit configuration for correcting the current input value (maximum DC voltage Vpn) input to current command calculator 131 according to the feedback signal from voltage limiter 137 . Figure 10
, the input value to the current command calculator 131 is corrected so that the maximum DC voltage Vpn becomes smaller according to the ratio (frequency, etc.) of voltage saturation. Similarly, the control device 10A may be provided with a circuit for correcting so that the command torque τre increases according to the rate at which voltage saturation occurs. Further, a circuit may be provided to correct so that the motor rotation speed v increases according to the rate at which voltage saturation occurs. In this way, the field-weakening control can be facilitated to be executed. Therefore, the circuit configuration for correcting the current input value (for example, the maximum DC voltage Vpn) input to the current command calculator 131 according to the feedback signal from the voltage limiter 137 illustrated in FIG. It can be said that this is an example of means for adjusting the current value of the d-axis current according to the extent to which a predetermined condition is satisfied with respect to the voltage that can be supplied by the power supply means.

<Other embodiments>
The process of measuring circuit parameters by the control device 10 of the first embodiment can be executed by a device other than the control device 10, for example, a computer connected to the control device 10 via a network. Further, the process of calculating the circuit parameters is performed by a computer that acquires, for example, the motor rotation speed of the motor 30, voltage command values (Vd, Vq), and measured current values (Id, Iq) via a storage medium or the like. can be executed in 5 to 7 of the first embodiment (calculation method of S12 to S14 of FIG. 5, processing of S141 and S142 of FIG. 7, etc.) may be executed by a computer other than the control device 10. .

FIG. 12 illustrates the configuration of a computer 100 that executes such processing. This computer 100 has a CPU 101, a main storage unit 102, and an external device connected via an interface (I/F), and executes information processing by a program. External storage unit 103, display unit 104, operation unit 105, and communication unit 106 can be exemplified as external devices.

The CPU 101 executes the processes exemplified in FIGS. 5 to 7 by a computer program developed in the main memory unit 102, and the calculated circuit parameters of the excitation circuit of the motor 30 are applied to the control device 10 of the first embodiment, It may be transferred to the control device 10A or the like of the second embodiment. The CPU 101, the main storage unit 102, and the I/F are examples of arithmetic units.

CPU 101 is also called a processor. The CPU 101 is not limited to a single processor, and may have a multiprocessor configuration. Also, the single CPU 101 may have a multi-core configuration.

The main storage unit 102 stores computer programs executed by the CPU 101, data processed by the CPU 101, and the like. The main storage unit 102 is a dynamic random access memory (DRAM), a static random access memory (SRAM), a read only memory (ROM), or the like. Furthermore, the external storage unit 103 is used, for example, as a storage area that assists the main storage unit 102, and stores computer programs executed by the CPU 101, data processed by the CPU 101, and the like. The external storage unit 103 is a hard disk drive, Solid State Disk (SSD), or the like. Furthermore, the computer 100 may be provided with a removable storage medium drive. Removable storage media are, for example, Blu-ray discs, Digital Versatile Disks (DVDs), Compact Discs (CDs), flash memory cards, and the like.

The computer 100 also has a display unit 104 , an operation unit 105 and a communication unit 106 . The display unit 104 is, for example, a liquid crystal display, an electroluminescence panel, or the like. The operation unit 105 is, for example, a keyboard, pointing device, or the like. In this embodiment, a mouse is exemplified as the pointing device. The communication unit 106 exchanges data with other devices on the network. A computer, by means of a computer program executable and deployed in memory,
<Computer-readable recording medium>
A program that causes a computer or other machine or device (hereinafter referred to as a computer or the like) to implement any of the functions described above can be recorded in a computer-readable recording medium. By causing a computer or the like to read and execute the program of this recording medium, the function can be provided.

Here, a computer-readable recording medium is a recording medium that stores information such as data and programs by electrical, magnetic, optical, mechanical, or chemical action and can be read by a computer, etc. Say. Examples of such recording media that can be removed from a computer or the like include memories such as flexible disks, magneto-optical disks, CD-ROMs, CD-R/Ws, DVDs, Blu-ray disks, DATs, 8 mm tapes, and flash memories. There are cards, etc. In addition, there are a hard disk, a ROM (read only memory), and the like as recording media fixed to a computer or the like. Furthermore, SSDs (Solid State Drives) can be used as recording media that can be removed from a computer or the like, or as recording media that are fixed to a computer or the like.
<Appendix>
1. The rotation speed of the electric motor (30) when the rotation speed is increased while maintaining the torque of the electric motor (30) at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotation speed, and the electric motor A value of the d-axis current in the excitation circuit when is the rotational speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a command value for the d-axis current in the excitation circuit means for acquiring a set of values including a command value for the d-axis voltage (S12);
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation Means (S14) for obtaining the circuit parameters of the excitation circuit by applying to a theoretical formula satisfied by the circuit parameters of the circuit;
A computing device (101, 102, 10) comprising means (S15, S4) for determining a parameter for adjusting the current value of the d-axis current when rotating the electric motor based on the acquired circuit parameter ).
2. means (133) for outputting a q-axis voltage command value for supplying a q-axis current to an excitation circuit of the electric motor;
means (132) for outputting a d-axis voltage command value for supplying a d-axis current to an excitation circuit of the electric motor;
power supply means (134, 135, 14) for supplying power to the motor based on the command value of the q-axis voltage and the command value of the d-axis voltage;
current detection means (15, 136) for detecting a current flowing through an excitation circuit of the electric motor;
speed detection means (16) for detecting the rotation speed of the electric motor;
and an arithmetic device, wherein the arithmetic device (101, 102, 10)
The rotational speed of the electric motor when the rotational speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotational speed, and the rotation speed A value of the d-axis current in the excitation circuit at the time of speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a d-axis voltage for causing the d-axis current in the excitation circuit a means (S12) for acquiring a set of values including a command value of
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation Means (S14) for obtaining the circuit parameters of the excitation circuit by applying to a theoretical formula satisfied by the circuit parameters of the circuit;
means (S15, S4) for determining a parameter for adjusting the current value of the d-axis current when rotating the electric motor based on the acquired circuit parameter (10).
3. The rotation speed of the electric motor (30) when the rotation speed is increased while maintaining the torque of the electric motor (30) at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotation speed, and the electric motor A value of the d-axis current in the excitation circuit when is the rotational speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a command value for the d-axis current in the excitation circuit obtaining a set of values including a command value for the d-axis voltage (S12);
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation obtaining the circuit parameters of the excitation circuit by applying to a theoretical formula satisfied by the circuit parameters of the circuit (S14);
a computer (101, 102, 10) determining a parameter for adjusting the current value of the d-axis current when rotating the electric motor based on the acquired circuit parameter (S15, S4); Operation method to perform.
4. the controller (10) outputting a q-axis voltage command value for supplying the q-axis current to the excitation circuit of the motor (133);
outputting a d-axis voltage command value for supplying a d-axis current to an excitation circuit of the electric motor (132);
(134, 135, 14) supplying electric power to the electric motor based on the command value of the q-axis voltage and the command value of the d-axis voltage;
detecting a current flowing through an excitation circuit of the electric motor;
(16) detecting the rotational speed of the electric motor;
The rotational speed of the electric motor when the rotational speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotational speed, and the value of the q-axis current in the excitation circuit of the electric motor at the rotational speed A value of a d-axis current in the excitation circuit at a rotational speed, a command value of a q-axis voltage for generating the q-axis current in the excitation circuit, and a d-axis for generating the d-axis current in the excitation circuit obtaining a set of values including a voltage command value (S12);
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation obtaining the circuit parameters of the excitation circuit by applying to a theoretical formula satisfied by the circuit parameters of the circuit (S14);
determining a parameter for adjusting the current value of the d-axis current when rotating the motor based on the acquired circuit parameter (S15, S4).
5. The rotation speed of the electric motor when the rotation speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotation speed, and the rotation speed of the electric motor A value of the d-axis current in the excitation circuit at the time of speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a d-axis voltage for causing the d-axis current in the excitation circuit obtaining a set of values including the command value of (S12);
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation obtaining the circuit parameters of the excitation circuit by applying to a theoretical formula satisfied by the circuit parameters of the circuit (S14);
determining parameters for adjusting the current value of the d-axis current when rotating the electric motor based on the obtained circuit parameters (S15, S4), to a computer (101, 102, 10); program to run.

10 control device 11 position controller 12 speed controller 13 current controller 14 inverter 15 current detector 16 speed detector 30 motor 32 position detector 131 current command calculator 132 d-axis current controller 133 q-axis current controller 134 voltage coordinate converter
135 PWM calculation unit 136 current coordinate converter

Claims (10)

The rotation speed of the electric motor when the rotation speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotation speed, and the rotation speed of the electric motor A value of the d-axis current in the excitation circuit at the time of speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a d-axis voltage for causing the d-axis current in the excitation circuit means for obtaining a set of values including command values for
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation means for obtaining circuit parameters of the excitation circuit by applying a theoretical formula satisfied by the circuit parameters;
and means for determining a parameter for adjusting the current value of the d-axis current when rotating the electric motor based on the acquired circuit parameter. 2. The arithmetic device according to claim 1, wherein the theoretical formula is given by formula A.
(Formula A)
Vd = RId - ωLqIq;
Vq = RIq + ωLdId + ωKemf;
(where Iq is the q-axis current, Id is the d-axis current, Vd is the d-axis voltage, Vq is the q-axis voltage, R is the motor phase resistance, Lq is the motor q-axis inductance corresponding to the magnetic flux caused by the q-axis current, Ld is the motor d-axis inductance corresponding to the magnetic flux due to the d-axis current, Kemf is the induced voltage constant, and ω is the electrical angular velocity corresponding to the rotation speed.) 3. The arithmetic unit according to claim 2, wherein the model formula is further determined by the set of values in the rotational speed range in which the value of the d-axis current is 0, and the theoretical formula is given by formula B.
(Formula B)
Vd = -ωLqIq;
Vq = RIq + ωKemf; means for outputting a q-axis voltage command value for supplying a q-axis current to an excitation circuit of the electric motor;
means for outputting a d-axis voltage command value for supplying a d-axis current to an excitation circuit of the electric motor;
power supply means for supplying power to the electric motor based on the command value of the q-axis voltage and the command value of the d-axis voltage;
current detection means for detecting a current flowing through an excitation circuit of the electric motor;
speed detection means for detecting the rotation speed of the electric motor;
and an arithmetic device, wherein the arithmetic device is
The rotational speed of the electric motor when the rotational speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotational speed, and the rotation speed A value of the d-axis current in the excitation circuit at the time of speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a d-axis voltage for causing the d-axis current in the excitation circuit means for obtaining a set of values including command values for
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation means for obtaining circuit parameters of the excitation circuit by applying a theoretical formula satisfied by the circuit parameters;
and means for determining a parameter for adjusting the current value of the d-axis current when rotating the motor based on the acquired circuit parameter. A combined value obtained by synthesizing the command value of the q-axis voltage and the command value of the d-axis voltage according to the phase difference between the q-axis voltage and the d-axis voltage is a predetermined value with respect to the voltage that can be supplied by the power supply means. 5. The motor control device according to claim 4, further comprising means for controlling the d-axis current to flow when a condition is satisfied. When the d-axis current is caused to flow, the current value of the d-axis current is set to a predetermined value by changing at least one of the obtained circuit parameter value and the suppliable voltage value of the power supply means by a compensation coefficient. 6. A motor control apparatus according to claim 5, further comprising means for reducing by a limit of . A combined value obtained by synthesizing the command value of the q-axis voltage and the command value of the d-axis voltage according to the phase difference between the q-axis voltage and the d-axis voltage is a predetermined value with respect to the voltage that can be supplied by the power supply means. 7. The motor control device according to any one of claims 4 to 6, further comprising means for adjusting the current value of said d-axis current in accordance with the degree to which a condition is satisfied. The rotation speed of the electric motor when the rotation speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotation speed, and the rotation speed of the electric motor A value of the d-axis current in the excitation circuit at the time of speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a d-axis voltage for causing the d-axis current in the excitation circuit obtaining a set of values including command values for
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation obtaining the circuit parameters of the excitation circuit by applying to a theoretical formula satisfied by the circuit parameters of the circuit;
determining a parameter for adjusting the current value of the d-axis current when rotating the electric motor based on the acquired circuit parameter; a control device outputting a q-axis voltage command value for supplying a q-axis current to an excitation circuit of the electric motor;
outputting a command value of a d-axis voltage for supplying a d-axis current to an excitation circuit of the electric motor;
supplying electric power to the electric motor based on the command value of the q-axis voltage and the command value of the d-axis voltage;
detecting a current flowing through an excitation circuit of the electric motor;
detecting the rotation speed of the electric motor;
The rotational speed of the electric motor when the rotational speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotational speed, and the value of the q-axis current in the excitation circuit of the electric motor at the rotational speed A value of a d-axis current in the excitation circuit at a rotational speed, a command value of a q-axis voltage for generating the q-axis current in the excitation circuit, and a d-axis for generating the d-axis current in the excitation circuit obtaining a set of values including a voltage command value;
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation obtaining the circuit parameters of the excitation circuit by applying to a theoretical formula satisfied by the circuit parameters of the circuit;
determining a parameter for adjusting the current value of the d-axis current when rotating the motor based on the acquired circuit parameter. The rotation speed of the electric motor when the rotation speed is increased while maintaining the torque of the electric motor at a predetermined value, the value of the q-axis current in the excitation circuit of the electric motor when the electric motor is at the rotation speed, and the rotation speed of the electric motor A value of the d-axis current in the excitation circuit at the time of speed, a command value of the q-axis voltage for causing the q-axis current in the excitation circuit, and a d-axis voltage for causing the d-axis current in the excitation circuit obtaining a set of values including command values for
A model expression determined by the set of values in the range of rotational speeds in which the value of the q-axis current is constant is expressed by the rotational speed of the motor, q-axis current, d-axis current, q-axis voltage, d-axis voltage, and excitation obtaining the circuit parameters of the excitation circuit by applying to a theoretical formula satisfied by the circuit parameters of the circuit;
determining a parameter for adjusting the current value of the d-axis current when rotating the electric motor based on the acquired circuit parameter.

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