JP5119759B2 - Electric motor control device and control method thereof - Google Patents

Description

  The present invention relates to an electric motor control device that performs speed control without a speed sensor and a control method thereof.

A conventional motor control device that performs speed control without a speed sensor superimposes an AC voltage signal, and estimates it from the estimated position using the superimposed AC voltage signal and the output current that flows at that time, and the voltage-current equation of the motor. Two estimated values of the position estimated value are switched according to the driving situation (see Patent Document 1).
FIG. 3 is a schematic block diagram of a conventional motor control device, in which 5 is an inverter, and voltage command values v ^* _{1, α} , v ^* _{1, β} are _added to high-frequency voltage command values v ^* _{h, α} , v ^* _h, A voltage with _β superimposed is input. Reference numeral 6 denotes a 3/2 phase conversion unit, which converts the voltages vu, vv, vw and currents iu, iv, iw detected from the inverter 5 to obtain voltages v _α , v _β and currents i _α , i _β . . 11 is a lambda _d arithmetic unit, the voltage v _alpha, v _beta current i _alpha, i _beta, the salient pole motor 2 q-axis inductance _{L q} and flux linkage lambda _d based _{on, alpha,} lambda _{d, beta} Ask for. Reference numeral 12 denotes a BPF unit which filters the number of magnetic flux linkages in the vicinity of the angular frequency ω _h to obtain high frequency components λ _{d, h, α} , λ _{d, h, β} . _{Reference numeral} 15 denotes an identification signal generator, which determines a high frequency component i _dh of the d-axis current. Reference numeral 13 denotes a position angle calculation unit which estimates and determines the rotational position angle θ _re of the salient pole motor 2 from the high frequency components λ _{d, h, α} , λ _{d, h, β} , i _dh .
As described above, the conventional motor control device superimposes the high frequency voltage on the inverter, obtains the number of magnetic flux linkages from the voltage and current at that time and the inductance of the salient pole motor, and calculates the number of magnetic flux linkages as the angular frequency of the superimposed signal. The first high-frequency component is obtained by filtering near the angular frequency, a second high-frequency component having an angular frequency near the angular frequency is obtained, and the salient pole motor is determined from the first high-frequency component and the second high-frequency component. The rotational position angle is estimated.
Japanese Patent Laying-Open No. 2005-160287 (FIG. 1)

The conventional motor control device superimposes the high-frequency voltage, and uses the set values of the voltage, current and salient pole motor inductance at that time to determine the number of magnetic flux linkages to estimate the rotational position angle. Since the motor electric constants to be set are required to be accurate and accurate values, there has been a problem that normal driving cannot be performed depending on the degree of error of these values.
The present invention has been made in view of such problems, and an electric motor control apparatus capable of robustly estimating the rotational position angle of an electric motor with respect to setting errors of voltage and current accuracy and electric constants of the electric motor. And it aims at providing the control method.

In order to solve the above problem, the present invention is configured as follows.
According to the first aspect of the present invention, a voltage command device that outputs a voltage command corresponding to a speed command to the motor, a voltage superimposing device that outputs an AC voltage command for phase compensation, and the speed command are integrated and corrected. By performing a correction process of adding a phase correction amount generated based on the motor current flowing through the motor to the phase command before correction generated by the integrator and the phase command generated by the integrator. an adder for generating a phase command after correction, a current detector for detecting the motor current, the motor current detected by said current detector, a phase command the same phase components of the corrected (gamma axis current), and the phase command to the 90-degree advanced phase component after correction ([delta] -axis current), the current coordinate converter for coordinate transformation respectively, converted the [delta] -axis current by the current coordinate converter from, the Using a current extractor for extracting a current amplitude of the same frequency component and an AC voltage command for phase compensation, the output from the current extractor, the current amplitude of the same frequency component and an AC voltage command for the phase compensation, said correction phase corrector that issues calculate the phase correction amount used in the said adder, said voltage command output from the voltage command unit, an AC voltage command for the phase compensation output from the voltage superimposing unit and, a voltage based on the phase command, after the correction generated by the adder, is characterized in that and a power converter for supplying the motor.

Further, the invention according to claim 2 is the invention according to claim 1, wherein the power converter has a phase component (δ-axis voltage) advanced by 90 degrees with respect to the voltage command. In addition , the AC voltage command is supplied to the electric motor as a voltage including a component (γ-axis voltage) having the same phase as the corrected phase command .
Further, the invention according to claim 3, in the invention of claim 1 or 2, wherein the current extractor, the a δ-axis current, the sine wave signal having the same frequency as the AC voltage command, a product a first multiplier for calculating the a δ-axis current, and the cosine wave signal having the same frequency as the AC voltage command, a second multiplier for calculating the product, the output from the first multiplier A first filter that performs low-pass filter processing, a second filter that performs low-pass filtering on the output from the second multiplier, an output from the first filter, and an output from the second filter And an amplitude calculator that calculates the current amplitude as components orthogonal to each other.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the phase corrector controls the current amplitude output from the current extractor to be zero. Thus, the phase correction amount is calculated.
The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the AC voltage command for phase compensation is a high-frequency signal.

In order to solve the above problem, the present invention is as follows.
According to a sixth aspect of the present invention, the first step of outputting a voltage command corresponding to the speed command to the motor, the second step of outputting an AC voltage command for phase compensation, and the speed command are integrated. A third step for generating a pre-correction phase command, and a correction process for adding a phase correction amount generated based on the motor current flowing through the motor to the pre-correction phase command generated in the third step. by performing a fourth step of generating a phase command after correction, the a fifth step of detecting a motor current flowing through the electric motor, the motor current detected by the fifth step, the corrected phase command the same phase component (gamma-axis current), and the phase command to the 90-degree advanced phase component after correction ([delta] -axis current), in the sixth step of the coordinate transformation, respectively, varying in the sixth step From been the δ-axis current, and a seventh step of extracting the current amplitude of the same frequency component and an AC voltage command for the phase compensation, the extracted in the seventh step, the same as the AC voltage command for the phase compensation using a current amplitude of the frequency component, the fourth and the eighth step that gives calculated the phase correction amount used in the correction process in the step, the voltage command output by the first step, the output at the second step AC voltage command for the phase compensation, and a wherein the fourth phase command after generated the correction in step, a voltage based on, with a, a ninth step of supplying to said electric motor To do.

  According to the invention described in the claims, the rotational position angle of the electric motor can be estimated robustly with respect to the setting error of the accuracy of the voltage and current and the electric constant of the electric motor. The speed control of the motor can be performed robustly.

  Hereinafter, specific examples of the method of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic block diagram of an electric motor control device of the present invention. In the figure, a voltage command device 21 performs FV conversion and outputs an induced voltage command proportional to a speed command ωref to the motor 24 as a δ-axis voltage command Vδref. The integrator 22 integrates the speed command ωref to generate a phase command θref. The current detector 30 detects motor currents Iu and Iw flowing through the motor 24, and the power converter 23 is a phase command in which a voltage command of Vδref is given as a δ-axis voltage command and a voltage command of Vγref as described later is a γ-axis voltage command. Although it is converted into a three-phase voltage command, and further not shown, three-phase voltages Vu, Vv, and Vw that are pulse width modulated using a carrier wave signal are generated and supplied to an electric motor 24 that is a load.

  The voltage superimposing unit 25 superimposes the AC voltage command on the γ-axis voltage command and outputs the γ-axis voltage command Vγref. The current coordinate converter 26 inputs the motor currents Iu and Iw detected by the current detector 30 and the phase component current (γ-axis current) and the phase component current advanced by 90 degrees (δ-axis current). ) And output as Iγ and Iδ, respectively. The current extractor 27 extracts a current Iδinj having the same frequency component as the γ-axis voltage command Vγref superimposed on the γ-axis voltage command from the δ-axis current Iδ. The phase corrector 28 calculates the phase correction amount Δθ using the extracted δ-axis current Iδinj. The adder 29 adds the phase command θref generated by the integrator 22 and the phase correction amount Δθ calculated by the phase corrector 28. In this way, the speed control of the electric motor 24 is performed.

  The difference between the present invention and the prior art is that two estimated values, a position estimated value estimated based on the superimposed AC voltage signal and the motor current at that time, and a position estimated value estimated based on the voltage-current equation of the motor are used as driving conditions. And the phase command is obtained as an addition value of the correction value Δθ calculated using the current value of the same frequency component as the AC voltage command superimposed with the integral value θref of the speed command. It is a part that.

In the following, the differences from the prior art will be described focusing on the calculation processing of the phase correction value Δθ.
The current coordinate converter 26 obtains the γ-axis current Iγ and the δ-axis current Iδ by the coordinate conversion shown in the equation (1) using the motor currents Iu and Iw detected by the current detector 30. At this time, Kirchhoff's law is obtained. The detection of one phase of the motor current (Iu, Iv, Iw) may be used as Iv = − (Iu + Iw). It should be noted that θ shown in equation (1) represents a corrected phase command θref ′ output from an adder 19 described later.

Next, the current extractor 27 has the configuration shown in FIG. 2, and the δ-axis current Iδ output from the current coordinate converter 26, the sin ωt signal, and the cos ωt signal (ω: the frequency of the superimposed AC voltage command). The product is multiplied using multipliers 41 and 42, and the multiplication results are input to low-pass filters 43 and 44, respectively, and the amplitude is obtained by the amplitude calculator 45 to obtain the extracted δ-axis current Iδinj. A current having the same frequency component ω as the superimposed γ-axis voltage command Vγref is obtained as the extracted δ-axis current Iδinj.
This process can be expressed as in equation (2), where T is the time constant of the low-pass filters 43 and 44, t is the time, and s is the Laplace transform operator. The time constant T of the low-pass filters 43 and 44 is desirably set to 10 / ω or less with respect to the frequency ω of the superimposed AC voltage command.

  Next, the phase corrector 28 performs PI (proportional / integral) control so that the extracted δ-axis current Iδinj becomes zero, and outputs a phase correction amount Δθ. The magnitude of the extracted δ-axis current Iδinj is based on the finding that it is proportional to the error between the control phase and the motor phase. This process can be expressed as in equation (3).

The adder 29 adds the phase correction amount Δθ obtained by the equation (3) and the phase command θref obtained by integrating the speed command ωref. This added value is input to the power converter 23 and the current coordinate converter 26 as a phase command θref ′.
In order to easily extract only the current component in the vicinity of the frequency ω of the AC voltage command Vγref superimposed by the current extractor 27, it is desirable that the frequency of the speed command has a difference as large as possible. That is, the frequency ω of the voltage command to be superimposed is desirably a high frequency.
In the above description, the output of the voltage command device 21 is the δ-axis voltage command Vδref, and the AC voltage command that is the output of the voltage superimposing device 25 is the γ-axis voltage command Vγref, but the motor electrical constant, motor current, and speed command The present invention is similarly applied to a configuration in which a voltage command for a γ-axis component is created using some and added to an AC voltage command that is an output of the voltage superimposing unit 25 to be a new γ-axis voltage command Vγref. Can be implemented.

In this way, the phase command is the integral value of the speed command value that is not affected by the motor electrical constant, current, and voltage information as the main phase information, and only the phase command and motor position correction amount are extracted by the voltage superposition method. Since the configuration is such that the calculation is performed based on the information, the speed control of the motor can be performed very robustly with respect to the setting error of the accuracy of the voltage and current and the electric constant of the motor.
In addition, in embodiment mentioned above, it can also apply to the reluctance motor which does not have a saliency motor which has a magnet, or a magnet.

1 is a schematic block diagram of an electric motor control device showing a first embodiment of the present invention. Configuration diagram of current extractor 27 of the present invention Schematic block diagram of a conventional motor control device

Explanation of symbols

2 Salient pole motor 5 Inverter 6 3/2 phase conversion unit 11 λ _d calculation unit 12 BPF unit 13 Position angle calculation unit 15 Identification signal generation unit 21 Voltage command unit 22 Integrator 23 Power converter 24 Electric motor 25 Voltage superimposer 26 Current Coordinate converter 27 Current extractor 28 Phase corrector 29 Adder 30 Current detector 41, 42 Multiplier 43, 44 Low-pass filter 45 Amplitude calculator

Claims (6)

A voltage command device that outputs a voltage command corresponding to a speed command to the motor;
A voltage superimposing device that outputs an AC voltage command for phase compensation;
An integrator that integrates the speed command to generate a phase command before correction ;
An adder for generating a corrected phase command by performing a correction process for adding a phase correction amount generated based on a motor current flowing through the motor to the phase command before correction generated by the integrator. When,
A current detector for detecting the motor current,
The motor current detected by the current detector is converted into a component having the same phase as the corrected phase command (γ-axis current) and a phase component advanced by 90 degrees with respect to the corrected phase command (δ-axis current). ), respectively, a current coordinate converter for coordinate transformation,
A current extractor that extracts the current amplitude of the same frequency component as the phase compensation AC voltage command from the δ-axis current converted by the current coordinate converter ;
The output from the current extractor, using the current amplitude of the same frequency component and an AC voltage command for the phase compensation, and the phase corrector that issues calculate the phase correction amount used in the correction process in the adder,
Said voltage command output from the voltage command unit, an AC voltage command for the phase compensation output from the voltage superimposing unit, and a voltage based on the phase command, after the correction generated by the adder, A power converter for supplying to the motor;
An electric motor control device comprising: The power converter is
Said voltage command, wherein while the phase command to the 90-degree advanced phase component after correction ([delta] -axis voltage), the AC voltage command, the phase command the same phase component (gamma-axis voltage) of the corrected The electric motor control device according to claim 1, wherein the electric motor is supplied to the electric motor as a voltage. The current extractor is
A first multiplier for calculating the a δ-axis current, the sine wave signal having the same frequency as the AC voltage command, a product,
Wherein the δ-axis current, and the cosine wave signal having the same frequency as the AC voltage command, a second multiplier for calculating a product,
A first filter that performs low-pass filtering on the output from the first multiplier;
A second filter that performs a low pass filtering on the output from the second multiplier;
An amplitude calculator that calculates the current amplitude using the output from the first filter and the output from the second filter as orthogonal components ;
The motor control device according to claim 1, comprising: The phase corrector is
4. The motor control device according to claim 1, wherein the phase correction amount is calculated by performing control so that the current amplitude output from the current extractor becomes zero. 5. . 5. The motor control device according to claim 1, wherein the phase compensation AC voltage command is a high-frequency signal. 6. A first step of outputting a voltage command corresponding to a speed command to the electric motor;
A second step of outputting an AC voltage command for phase compensation;
A third step of integrating the speed command to generate a phase command before correction ;
A correction process for adding a phase correction amount generated based on the motor current flowing in the motor to the phase command before correction generated in the third step is performed to generate a corrected phase command. 4 steps,
A fifth step of detecting a motor current flowing through the motor;
The motor current detected in the fifth step is divided into a component having the same phase as the corrected phase command (γ-axis current) and a phase component advanced by 90 degrees with respect to the corrected phase command (δ-axis current). ) And 6th step of transforming the coordinates respectively ,
A seventh step of extracting a current amplitude having the same frequency component as the AC voltage command for phase compensation from the δ-axis current converted in the sixth step ;
The seventh extracted in step, by using the current amplitude of the same frequency component and an AC voltage command for the phase compensation, and the eighth step that gives calculated the phase correction amount used in the correction process in the fourth step ,
Said voltage command output by the first step, an AC voltage command for the phase compensation output in the second step, and a voltage based on the phase command, after the correction generated by the fourth step A ninth step of supplying the electric motor;
A control method for an electric motor control device.