JP3979102B2 - Electric motor control method and control apparatus therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention determines the magnitude of the current to be passed in proportion to the electromagnetic force command, determines the electrical angle command of the current based on the armature position state quantity of the mover, and generates the excitation current. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control method for generating an electromagnetic force by energizing an excitation current and a control apparatus therefor, and in particular, a short time detection of a magnetic pole of a motor that is performed prior to normal operation (actual operation) of the motor without using a magnetic pole position sensor. In addition, the present invention relates to a technique for performing with high accuracy.
The electromagnetic force command in the present invention is a thrust command of an inverter control device in a linear motor, and a torque command in a rotary motor. That is, an electromagnetic force command is defined and used as a concept including both a thrust command and a torque command.
[0002]
[Prior art]
The magnitude of the current to be energized is determined in proportion to the electromagnetic force command, and the electrical angle command for the current is determined based on the armature position state quantity of the mover to generate an excitation current. In the control method and the control device for the electric motor that generates electromagnetic force by determining the relative position between the mover and the stator of the motor, the electric current that is applied so that the electromagnetic force is efficiently generated at the position of the mover The electrical angle command is determined.
In order to obtain the relative position between the mover and the stator of the motor, a magnetic pole position sensor is installed inside the motor to detect the magnetic pole position of the mover, and an absolute value encoder (for example, a rotary type) is installed inside the motor. Means to detect the absolute position of the rotation angle of the mover used in an electric motor) and install a means to detect the absolute position of the mover, or install a current detector for each phase flowing in the coil There are means for measuring a current value and detecting a phase difference of each phase current. However, it is necessary to insert these detectors in the electric motor or install them around the motor and connect the signal lines of the detector to the control device. is there.
[0003]
As a means for obtaining the relative position between the mover and the stator of an electric motor without using a magnetic pole position sensor, an absolute value encoder or a current detector, a conventional example according to Japanese Patent No. 3114817 (hereinafter referred to as a first conventional example) There is.
FIG. 13 is an explanatory view showing a first conventional example.
The electric motor used in the first conventional example is a rotary electric motor having U-phase, V-phase and W-phase three-phase stator windings. When the currents (excitation currents) iu, iv, and iw that change sinusoidally as shown in FIG. 13 are energized, the generated torque T, the rotational angular velocity dθ / dt, and the rotational angle θ of the motor are respectively shown in FIGS. 13B, 13C, and 13C. As shown in (d). In other words, since the phase difference between the excitation current and the torque that changes sinusoidally at the excitation frequency and the excitation current changes depending on the magnetic pole position at which it is stopped, this generated torque or the rotation angular velocity or rotation angle generated thereby is detected and From the phase difference from the excitation current (the phase difference is π / 2 in FIG. 13B), the relative position between the mover and the stator of the motor is obtained.
[0004]
In addition, as a means for obtaining the relative position between the mover and the stator without using a magnetic pole position sensor, an absolute value encoder, a current detector, or the like, the conventional technique disclosed in Japanese Patent Application Laid-Open No. 7-322678 filed by the applicant of the present application. There is an example (hereinafter referred to as a second conventional example).
The electric motor used in the second conventional example is driven by vector control, and when the position φ of the field pole is unknown and the electric motor can be driven only in one direction, the generated electromagnetic force is desired. When accelerating in the direction, after obtaining the field pole position from the position data x and determining the phase ρ of the exciting current to be energized, hold the phase offset amount γ for a while and then update it to the next phase offset amount γ When the generated electromagnetic force accelerates in the direction opposite to the desired driving direction, a means for immediately updating to the next phase offset amount is provided.
FIG. 14 is a flowchart showing the flow of the second conventional example.
That is, step 141 gives a thrust command that matches the direction to be driven, step 142 initializes the time for changing the phase offset amount γ, and step 143 initializes the phase offset amount γ of the excitation current. In step 144, the phase ρ of the exciting current to be energized is calculated. The phase ρ of the energizing excitation current is obtained from the field pole position θ calculated from the position data x and the phase offset amount γ.
Step 145 determines the polarity of the acceleration. The acceleration can be obtained from the second derivative of position or the first derivative of velocity. If the acceleration polarity matches the direction to be driven by the thrust command given in step 141, the process proceeds to step 146, and if not, the process proceeds to step 148. In step 146, the time is determined. It is determined whether or not the offset amount is equal to or less than the time tmax that can be given without being changed. If it is less than the time tmax that can be given, the process proceeds to step 147. In step 147, the time is updated. In step 148, the phase offset amount γ is updated. Step 149 does the same as step 142.
In this way, the driving direction is confirmed by looking at the acceleration. If the polarity of the acceleration does not match the direction to be driven by the thrust command, the phase offset amount γ is updated, so the motor is driven in a specific direction. .
[0005]
[Problems to be solved by the invention]
(First problem) When magnetic pole detection is performed without using a magnetic pole position sensor, absolute value encoder, or current detector, the motor mover of the motor is operated while energizing the excitation current. It is necessary to detect the position or speed. Therefore, the mover must be operated with an exciting current having a magnitude sufficient to detect the state quantity of the position or speed. However, if the position or speed of the mover increases, the mover will move correspondingly, and in some cases, there is a risk that the controlled object operated by the electric motor will come into contact with an obstacle or the like.
In the first conventional example, currents (excitation currents) iu, iv, and iw that change in a sine wave shape are energized as shown in FIG. 13A, and the phase difference between the state quantity of the position or speed and the excitation current is detected. ing. Further, in the second conventional example, the position or speed at the time of operation is detected, and the acceleration is obtained from the second-order derivative of the position or the first-order derivative of the speed.
At this time, in order to prevent the mover from operating largely, a means for reducing the amplitude (magnitude) of the energized excitation current to some extent must be taken. However, if the amplitude of the excitation current is reduced, there is a problem in that the speed of the mover becomes small due to the influence of external forces such as friction and cogging, and the position or speed state quantity of the mover cannot be detected. In addition, when the cause of mechanical loss caused by friction or the like is small and the cable connected to the mover has a large cable tension (refers to the force acting on the mover by the cable) ( For example, when the air-floating bearing is used) or when the cogging force (Cogging Torque: force generated by the change in the attractive force between the permanent magnet of the rotor and the stator core teeth) is large, the cable tension or The cogging force may exceed the electromagnetic force generated by the energized excitation current, and the mover moves in the opposite direction to the acting electromagnetic force, so the correct phase difference is not detected or the direction of acceleration is applied. There is a case in which the direction of the electromagnetic force does not match, and the magnetic pole cannot be detected with high accuracy. Also, in a linear motor in which the mover is guided by air levitation type or magnetic levitation type bearings, steep acceleration may act on the mover because the static friction force greatly exceeds the dynamic friction force. There is a problem that the mover moves greatly.
After all, in order to detect magnetic poles with high accuracy, it is necessary to apply a large amplitude excitation current to operate the mover. As a result, the mover moves greatly, and the controlled object becomes an obstacle. There was a problem that it might come into contact with.
[0006]
(Second Problem) In the first conventional example, in order to prevent the mover from operating largely, there is provided means for reducing the amplitude of the exciting current to be energized and setting the sine wave energized as the exciting current to a high frequency. Conceivable. If the frequency of the exciting current to be energized becomes higher, the speed corresponding to the first order integration or the position corresponding to the second order integration becomes smaller than when the frequency is low, and the force acting in a certain direction is applied only for a short time. Since the speed generated by the force is reduced by disturbance such as friction, the amount of movement of the mover is reduced, and the possibility that the controlled object comes into contact with an obstacle is reduced.
However, if the frequency of the energized exciting current is increased, it is impossible to accurately obtain the phase difference between the measured position or speed and the energized exciting current.
[0007]
The reason for this will be described with reference to FIG.
FIG. 15 shows time series data of the excitation current and the mover speed that appear when the magnetic pole is detected based on the first conventional example with a high frequency sine wave that is energized as the excitation current.
In this example, the control angular frequency of the control device is set to 0.5 ms, and the excitation current to be energized is set as a sine wave of 166.7 Hz to detect the rotational angular velocity. The excitation current energized at this time is as shown in FIG. 15A, and the measured rotational angular velocity is as shown in FIG. 15B. The controller attempts to energize the ideal current commands iu ′, iv ′, and iw ′ shown in FIG. 15 (a). However, since the control calculation cycle of the controller is 0.5 ms, it is actually energized. The exciting current is like iu, iv and iw, and has a rough waveform that changes stepwise. The measured rotational angular velocity is as shown in FIG. 15B, but since the control calculation cycle of the control device is 0.5 ms, this velocity also has a rough waveform that changes stepwise.
When the phase difference is obtained from such rough waveforms, a large error is included. In the example shown in FIG. 15, the control calculation cycle of the control device is 0.5 ms, and the frequency of the exciting current to be energized is 166.7 Hz, but the 166.7 Hz sine wave advances during the control calculation cycle of 0.5 ms. The phase angle is 166.7 × 0.0005 × 360 = 30 degrees, and the magnetic pole detection result includes an error at least within this range, and it is impossible to obtain the phase difference with high accuracy.
Generally, the accuracy of magnetic pole detection is preferably within ± 7 degrees in electrical angle. Therefore, in order to maintain this accuracy in implementing the first conventional example, it is necessary to energize a sine wave of at least 39 Hz or less.
After all, in order to detect magnetic poles with high accuracy, it is necessary to energize the mover by applying an excitation current at a low frequency. As a result, the mover moves greatly, and the controlled object becomes an obstacle, etc. There was a problem that it might come into contact with.
[0008]
(Third Problem) In the second conventional example, the position or speed at the time of operation is detected, and the acceleration is obtained from the second derivative of the position or the first derivative of the speed. In this case, the magnetic pole It is assumed that the speed of the mover is close to zero at the start of detection. However, when the cable tension is large or the like, there are many cases where the mover is not completely stationary, and there is a problem that the magnetic pole detection itself cannot be performed until the speed of the mover becomes a value close to zero.
[0009]
(Fourth Problem) In the second conventional example, the procedure is to operate the mover while energizing the current, determine the polarity of acceleration in step 145 of FIG. 14, and update the phase offset amount γ in step 148. It is necessary to repeat until the polarity of the acceleration matches the direction to be driven.
For this reason, depending on the initial magnetic pole position, it may take a long time for the phase offset amount γ to reach an appropriate value, and there is a problem that the magnetic pole cannot be detected in a short time.
[0010]
Therefore, in order to solve the first to fourth problems, the present invention does not use a magnetic pole position sensor, an absolute value encoder or a current detector, and without greatly moving the mover during magnetic pole detection. On the other hand, an object of the present invention is to provide an electric motor control method and a control apparatus thereof capable of detecting magnetic poles in a short time and with high accuracy even when the mover is moving during magnetic pole detection.
[0011]
[Means for Solving the Problems]
In order to solve the first problem to the fourth problem, the present invention does not use a magnetic pole position sensor, an absolute value encoder, or a current detector, so that the mover does not move greatly at the time of magnetic pole detection and vice versa. It is an object of the present invention to provide an electric motor control method and a control apparatus thereof capable of detecting magnetic poles in a short time and with high accuracy even when the mover is moving during magnetic pole detection. The magnitude of the current to be applied is determined in proportion to the electromagnetic force command T (t) at the time of magnetic pole detection, which is a periodic function having a short period, and changes within a certain range as time t passes. The electrical angle command ψ (t) of the current is determined based on the slip command ω (t) and the armature position state quantity Φ (t) to generate an exciting current, and the speed state quantity v of the mover at that time (T) is measured and the mover The response ratio req (t) is calculated from the ratio of the state quantity to the magnetic force detection electromagnetic force command T (t) using the position, speed, or acceleration as the state quantity, and the response ratio req (t) and the slip command ω (t ) And the magnetic pole detection operation is performed by the procedure of identifying the magnetic pole offset amount θ.
That is, the motor control method of the present invention determines the magnitude of the current to be energized in proportion to the electromagnetic force command, and determines the electrical angle command of the current based on the armature position state quantity of the mover. In the motor control method for generating an electromagnetic current by generating an exciting current and energizing this exciting current,
When identifying the magnetic pole offset amount θ of the motor before actual operation of the motor, when the armature position state quantity at time t is Φ (t) and the electrical angle command is ψ (t), Electromagnetic force command generation step S1 for generating a magnetic pole detection electromagnetic force command T (t) by a periodic function having a short cycle, and a slip command generation for generating a slip command ω (t) that changes within a certain range as time t passes. During step S2 and a predetermined time, the magnitude of the current to be energized is determined so as to be proportional to the magnetic force detection electromagnetic force command T (t), and the armature position state quantity Φ (t) and the slip command are determined. Based on ω (t), the electrical angle command ψ (t) is determined to generate an excitation current, and an electromagnetic force is generated by energizing the excitation current, and the movable element is moved during the predetermined time. Speed state Measurement step S3 for measuring v (t), and the response ratio req (t) from the ratio of the state quantity to the electromagnetic force command T (t) at the time of magnetic pole detection, with the position, speed or acceleration of the mover as the state quantity The magnetic pole detection operation is performed by the procedure of the magnetic pole offset amount calculation step S4 for comparing the response ratio req (t) and the slip command ω (t) to identify the magnetic pole offset amount θ. In actual operation, the magnitude of the current to be energized is determined in proportion to the electromagnetic force command, and the electrical angle command is determined based on the armature position state quantity Φ (t) and the magnetic pole offset quantity θ. An excitation current is generated by determining ψ (t), and an electromagnetic force is generated by applying the excitation current.
In addition, the motor control device of the present invention includes an integrator that integrates the speed state quantity output from the speed detector of the motor and converts it into an armature position state quantity, a target value, the armature position state quantity, and / or Or a feedback controller that outputs an electromagnetic force command based on the speed state quantity, an electromagnetic force command switch, an electrical angle switch, a current converter, an adder, and a magnetic pole offset identifier. In preparation for
When identifying the magnetic pole offset amount of the motor before actual operation of the motor, first, the integrator value is cleared, and the magnetic force detection time electromagnetic force command output from the magnetic pole offset amount identifier is the electromagnetic force. A slip command that is input to the current converter via the command switch and output from the magnetic pole offset amount identifier is input to the adder together with the armature position state quantity via the electrical angle switch. The adder calculates the sum of the input armature position state quantity and the slip command and outputs an electrical angle command, and the current converter energizes the current so as to be proportional to the electromagnetic force command when detecting the magnetic pole. Is determined, and an excitation current is output based on the electrical angle command, and the magnetic pole offset identifier identifies the magnetic pole offset as a state in which the velocity state quantity is input. It performs the magnetic pole detection operation to identify,
In actual operation, the electromagnetic force command output from the feedback controller is input to the current converter via the electromagnetic force command switch, and the magnetic pole offset amount output from the magnetic pole offset amount identifier Is input to the adder together with the armature position state quantity via the electrical angle switch, and the adder calculates the sum of the input armature position state quantity and the magnetic pole offset quantity to calculate an electrical angle command. In the current converter, the magnitude of the current to be energized is determined in proportion to the electromagnetic force command, and the excitation current is output based on the electrical angle command.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the motor control apparatus according to the first embodiment of the present invention. FIG. 2 is a flowchart showing a flow of magnetic pole detection operation in the first embodiment of the present invention. 3 and 4 show time-series data of the results when the magnetic pole detection operation is performed based on the first embodiment of the present invention, and FIG. 4 is a partial enlarged view of FIG. It is. FIG. 5 is an explanatory diagram showing the result of identifying the magnetic pole offset amount based on the first embodiment of the present invention.
In FIG. 1, reference numeral 101 denotes a control device that causes the electric motor 103 to generate an electromagnetic force by energizing the electric motor 103 with an excitation current 102.
The speed of the electric motor 103 is detected by the speed detector 104, and the detected speed state quantity v (t) is fed back to the control device 101. However, t means time.
The control device 101 includes therein an integrator 107 that integrates the speed state quantity v (t) and converts it into an armature position state quantity Φ (t), a target value 108 generated by target value generation means (not shown), and an electric machine. A feedback controller 111 that outputs an electromagnetic force command 110 based on the child position state quantity Φ (t) and / or the speed state quantity v (t), an electromagnetic force command switch 112, an electrical angle switch 113, and a current converter 114. , An adder 115 and a magnetic pole offset amount identifier 117 for outputting the magnetic pole offset amount θ.
During normal operation (actual operation), both the electromagnetic force command switching unit 112 and the electrical angle switching unit 113 are in the position a, and the electromagnetic force command 110 output from the feedback controller 111 changes the electromagnetic force command switching unit 112. Via the current converter 114. The magnetic pole offset amount θ is input to the adder 115 together with the armature position state amount Φ (t) via the electrical angle switch 113. The adder 115 outputs an electrical angle command Ψ (t) = θ + Φ (t), which is the sum of the magnetic pole offset amount θ and the armature position state quantity Φ (t), and inputs it to the current converter 114. The current converter 114 determines the magnitude of the current to be supplied in proportion to the electromagnetic force command 110 and outputs the excitation current 102 based on the electrical angle command Ψ (t).
[0013]
Here, the speed detector 104 is, for example, an incremental encoder, and when the control device 101 is started (for example, when the control device 101 is powered on), the speed detector 104 Since the relative position with respect to the stator is unknown, the magnetic pole offset amount θ determined from the relative position between the mover and the stator in the electric motor 103 is identified prior to the actual operation of the electric motor 103.
That is, the value of the integrator 107 is cleared by a reset signal (not shown), and both the electromagnetic force command switch 112 and the electrical angle switch 113 are switched to the position b. Then, the speed state quantity v (t) can be input to the magnetic pole offset quantity identifier 117, and the magnetic force detection electromagnetic force command T (t) output from the magnetic pole offset quantity identifier 117 is changed to the electromagnetic force command switch 112. The slip command ω (t) that is input to the current converter 114 via the magnetic pole and output from the magnetic pole offset amount identifier 117 is added together with the armature position state quantity Φ (t) via the electrical angle switch 113. The state is input to 115. The adder 115 outputs an electrical angle command Ψ (t) = ω (t) + Φ (t), which is the sum of the slip command ω (t) and the armature position state quantity Φ (t), and the current converter 114. The current converter 114 determines the magnitude of the current to be applied in proportion to the electromagnetic force command T (t) at the time of magnetic pole detection, and outputs the excitation current 102 based on the electrical angle command Ψ (t) to perform the magnetic pole detection operation. To identify the magnetic pole offset amount θ. Finally, both the electromagnetic force command switching unit 112 and the electrical angle switching unit 113 are returned to the position a, and the actual operation is started.
[0014]
The magnetic pole detection operation is performed by the magnetic pole offset amount identifier 117 according to the flowchart shown in FIG.
In the electromagnetic force command generation step S1, an electromagnetic force command T (t) at the time of magnetic pole detection is generated.
The electromagnetic force command T (t) at the time of magnetic pole detection is a periodic function, and the period of the periodic function is shortened so that the controlled object does not come into contact with an obstacle or the like.
The period of this periodic function is preferably 2n times the control calculation period of the control device 101 (where n is a natural number).
The periodic function is preferably a trapezoidal wave, a rectangular wave, a triangular wave, or a sine wave.
When the period of this periodic function becomes close to the control calculation period of the control device 101 due to the influence of the electromagnetic force command T (t) at the time of magnetic pole detection being discretized for each control calculation period, the periodic function becomes trapezoidal, rectangular Although the waveform is close to a wave or a triangular wave, no particular problem occurs.
[0015]
In addition, since the mover may move transiently at the start of the magnetic pole detection operation, in order to remove this transient phenomenon, the electromagnetic force command T (t) at the time of magnetic pole detection is determined at the start of measurement step S3 described later. Assuming that the amplitude is close to zero, a function in which the amplitude gradually increases monotonously until a certain time is reached.
Further, when there is a concern about a transient phenomenon at the end of the magnetic pole detection operation, the magnetic force command T (t) at the time of magnetic pole detection is assumed to have an amplitude close to zero at the end of the measurement step S3, which will be described later. After reaching the value, the function may be a function whose amplitude gradually and monotonously decreases.
As an example of the electromagnetic force command T (t) at the time of magnetic pole detection that satisfies such a condition, the following function can be considered.
T (t) = a (t) × sin (2πft)
Where f is the frequency of the electromagnetic force command T (t) at the time of magnetic pole detection (reciprocal of the period), and the function a (t) represents the amplitude. For example, a trapezoidal wave or a trapezoidal wave is smoothed. Etc.
[0016]
In this way, the magnetic force detection electromagnetic force command T (t) is a periodic function having a short period (for example, a trapezoidal wave, a rectangular wave, a triangular wave, or a sine wave), and the period of this periodic function is the control calculation period of the control device 101. 2n times (where n is a natural number), and by moving the mover smoothly during the magnetic pole detection operation, the magnetic pole can be detected without causing the mover to move greatly.
[0017]
In addition, the amplitude of the electromagnetic force command T (t) at the time of magnetic pole detection is close to zero at the start of the measurement step S3, and the amplitude gradually increases monotonously until a certain time is reached, and the amplitude at the end of the measurement step S3. As a function where the amplitude is gradually monotonously reduced after a certain time is reached, there is no transient phenomenon in the magnetic pole detection operation, so the magnetic pole is detected without the mover moving greatly. It can be performed.
[0018]
In the slip command generation step S2, a slip command ω (t) that changes within a certain range with the passage of time t is generated. The slip command ω (t) is a function having a change of at least an electrical angle of ½ rotation or more during a predetermined time in the measurement step S3 described later.
[0019]
In this way, the slip command ω (t) is a function having a change of at least an electrical angle of 1/2 rotation or more during a predetermined time, so that the electromagnetic force command T (t) at the time of magnetic pole detection is Since at least one electrical angle at which the electromagnetic force is strongest is included, magnetic pole detection can be performed in a short time and with high accuracy.
[0020]
In the measurement step S3, the magnitude of the current to be energized is determined so as to be proportional to the magnetic force command T (t) during magnetic pole detection for a predetermined time, and the armature position state quantity Φ (t) and the slip command ω ( t), an electrical angle command ψ (t) is determined to generate an exciting current, an electromagnetic force is generated by energizing the exciting current, and a velocity state quantity v ( t) is measured. Specifically, the following steps S31 to S36 are performed. First, in step S31, the time t is initialized to t = 0, and the value of the armature position state quantity stored in the integrator 107 is initialized to Φ (0) = 0. Next, in step S32, the sum of the armature position state quantity Φ (t) and the slip command ω (t) is calculated by the adder 115 to obtain the electrical angle command Ψ (t) = Φ (t) + ω (t). decide. Next, in step S33, the magnitude of the excitation current is determined based on the magnetic force detection electromagnetic force command T (t), and the current converter 114 generates the excitation current based on the electrical angle command ψ (t). . Next, in step S34, the velocity state quantity v (t) of the mover at this time is measured by the velocity detector 104. Next, it is determined whether or not the predetermined time has been reached in step S35. If this continuation condition is not satisfied, the process proceeds to S36, and if the continuation condition is satisfied, the measurement step S3 is terminated. In step S36, the value of time t is updated by t = t + DT. Here, DT is a control calculation cycle of the control device 101.
[0021]
In the magnetic pole offset amount calculation step S4, the response ratio req (t) is calculated from the ratio of the state amount to the electromagnetic force command T (t) at the time of magnetic pole detection using the position, velocity or acceleration of the mover as the state amount. The magnetic pole offset amount θ is identified by comparing the ratio req (t) with the slip command ω (t). Specifically, the following steps S41 and S42 are performed.
First, in step S41, the response ratio req (t) of the state quantity of the mover with respect to the electromagnetic force command T (t) at the time of magnetic pole detection is calculated.
In calculating the response ratio req (t), the following method 1 to method 6 can be considered as examples.
[0022]
[Method 1] The response ratio req (t) is defined only at time t when the magnetic force detection electromagnetic force command T (t) becomes an extreme value, and the first-order derivative of the speed state quantity v (t) near the time t. When the time when the value dv (t) / dt takes an extreme value is t ′,
req (t) = (dv (t ′) / dt) / T (t)
Calculated by
[0023]
[Method 2] The response ratio req (t) is defined only at time t when the first-order integral value ST (t) of the electromagnetic force command T (t) at the time of magnetic pole detection becomes an extreme value, and the speed state is near the time t. When the time when the amount v (t) takes an extreme value is t ′,
req (t) = v (t ′) / ST (t)
Calculated by
[0024]
[Method 3] The position state quantity x (t) obtained by integrating the speed state quantity v (t) is calculated in advance, and the response ratio req (t) is the second-order integral of the electromagnetic force command T (t) during magnetic pole detection. When the value SST (t) is defined only at the time t when the extreme value is reached, and the time when the position state quantity x (t) takes the extreme value in the vicinity of the time t is defined as t ′,
req (t) = x (t ′) / SST (t)
Calculated by
[0025]
[Method 4] The response ratio req (t) is defined only at time t when the magnetic force detection electromagnetic force command T (t) becomes an extreme value, and the first-order derivative of the speed state quantity v (t) near the time t. In a time domain in which the value dv (t) / dt has the same sign, a value obtained by integrating the first-order differential values dv (t) / dt is defined as Sdv (t).
req (t) = Sdv (t) / T (t)
Calculated by
[0026]
[Method 5] The response ratio req (t) is defined only at time t when the first-order integral value ST (t) of the electromagnetic force command T (t) at the time of magnetic pole detection becomes an extreme value, and the speed state is near the time t. In the time domain where the amount v (t) has the same sign, the value obtained by integrating the speed state amount v (t) is Sv (t).
req (t) = Sv (t) / ST (t)
Calculated by
[0027]
[Method 6] The position state quantity x (t) obtained by integrating the speed state quantity v (t) is calculated in advance, and the response ratio req (t) is the second-order integral of the electromagnetic force command T (t) during magnetic pole detection. A value obtained by integrating the position state quantity x (t) in the time domain where the value SST (t) is defined only at the time t when the extreme value is reached and the position state quantity x (t) has the same sign in the vicinity of time t. As Sx (t),
req (t) = Sx (t) / SST (t)
Calculated by
[0028]
As described above, the response ratio req (t) of the state quantity of the mover with respect to the electromagnetic force command T (t) at the time of magnetic pole detection is calculated by any one of the methods 1 to 6. Thus, the response ratio req (t) becomes maximum when the armature position state quantity Φ (t) and the slip angle ω coincide with each other, and the armature position state quantity Φ (t) and the slip angle ω become electric. When the angle is shifted by ± π / 2, it becomes zero, and when the armature position state quantity Φ (t) and the slip angle ω are shifted by π by the electrical angle, it has the property of being minimum. Magnetic pole detection can be performed with high accuracy.
Moreover, although the method 1 to the method 6 have been disclosed as the response ratio calculation method, the method is not limited to this method, and the response ratio req (t) is determined by the armature position state quantity Φ (t), the slip angle ω, and the like. , The armature position state quantity Φ (t) and the slip angle ω are zero when the electrical angle is shifted by ± π / 2, and the armature position state quantity Φ (t ) And the slip angle ω are shifted by π in electrical angle, it is needless to say that a highly accurate magnetic pole offset amount can be identified if the feature amount has the property of being minimized.
[0029]
Next, in step S42, the magnetic pole offset amount θ is identified by comparing the response ratio req (t) with the slip command ω (t). As an example of the identification method, the absolute value of the response ratio | req (t) | during the predetermined time or the average value of the absolute value of the response ratio | req (t) | multiplied by π / 2 Where reqmax is an absolute value of reqmax × cos (ω (t) −θ ′) − req (t), a squared value or the like as an evaluation amount, and a value obtained by integrating the evaluation amount for a predetermined time is a minimum. A value of θ ′ that can be calculated as follows, and this value θ ′ may be used as the magnetic pole offset amount θ.
[0030]
In this way, by integrating the evaluation amount for a predetermined time, calculating the value of θ ′ that minimizes the integrated value, and setting this value as the magnetic pole offset amount θ, the magnetic pole can be accurately obtained. Detection can be performed.
Although the integration time of S42 is a predetermined time, the electromagnetic force command T (t) at the time of magnetic pole detection is assumed to have an amplitude close to zero at the start of the measurement step S3. When the amplitude is a function that increases monotonously slowly, or when the magnetic force detection electromagnetic force command T (t) is close to zero at the end of the measurement step S3, In the case of a function in which the amplitude gradually decreases monotonously, a large error factor may be included in the speed during the increase or decrease. Therefore, the amplitude a (t) of the electromagnetic force command T (t) at the time of magnetic pole detection In the time domain where) is not a constant value, it is more preferable not to perform integration.
Further, as a method for identifying the magnetic pole offset amount θ, a method for integrating the evaluation amount described above and calculating θ ′ that minimizes the integral value has been disclosed. However, the present invention is not limited to this method. The slip command value ω (t) at the time when the value of the response ratio req (t) is maximum is set as the magnetic pole offset amount θ, or the value of the slip command at the time when the value of the response ratio req (t) is minimum. A value ω (t) + π obtained by adding a phase corresponding to 1/2 electrical angle is used as a magnetic pole offset amount θ, or an electrical angle ± 1/1 is added to a slip command value at a time when the value of the response ratio req (t) becomes zero. Needless to say, the magnetic pole offset amount θ can be identified with high accuracy by a method in which the value ω (t) ± π / 2 obtained by adding the phases for four rotations is used as the magnetic pole offset amount θ. In addition to this, many methods of extracting the characteristics of the response ratio req (t) and the slip command ω (t) and identifying the magnetic pole offset amount θ from the characteristics are conceivable.
When the magnetic pole detection operation is performed in the above steps, the most preferable magnetic pole offset amount θ is identified.
[0031]
As described above, when the magnetic pole offset amount θ of the motor is identified prior to the actual operation of the motor, the electromagnetic force command generation step S1 that generates the magnetic force detection electromagnetic force command T (t) by a periodic function having a short period; The slip command generation step S2 for generating a slip command ω (t) that changes within a certain range with the lapse of time t, and energization so as to be proportional to the electromagnetic force command T (t) at the time of magnetic pole detection for a predetermined time. The magnitude of the current is determined, an electrical angle command ψ (t) is determined based on the armature position state quantity Φ (t) and the slip command ω (t), and an excitation current is generated. An electromagnetic force is generated by energization, and a measurement step S3 for measuring the velocity state quantity v (t) of the mover for a predetermined time, and the position, velocity, or acceleration of the mover as the state quantity, and electromagnetic at the time of magnetic pole detection Force command The response ratio req (t) is calculated from the ratio of the state quantity to T (t), and the response ratio req (t) is compared with the slip command ω (t) to identify the magnetic pole offset quantity θ. By performing the magnetic pole detection operation in the procedure with the calculation step S4, a high-frequency excitation current is energized, so that the magnetic pole can be detected with high accuracy in a short time without the mover moving greatly. In addition, since magnetic pole detection can be performed in a short time, even when the excitation current in the magnetic pole detection operation is large, the amount of heat generated from the mover and the current converter can be reduced.
[0032]
The result of carrying out this magnetic pole detection operation with a linear motor having three-phase windings of U, V and W phases will be described. The control apparatus for the linear motor in this experiment has a control calculation cycle of DT = 312.5 μs, outputs an electromagnetic force command every time DT seconds, and measures the speed state quantity v (t). Further, the electromagnetic force command at the time of magnetic pole detection generated in the electromagnetic force command generation step S1 is
T (t) = a (t) × sin (2π × 400 × t),
a (t) = a × t / 0.25 (t <0.25), a (t ≧ 0.25)
And a sine wave having a cycle of 400 Hz, which is eight times the control calculation cycle. Here, a is the maximum amplitude (thrust) [N] of the electromagnetic force command to be energized, and t is the time [second]. Note that the electromagnetic force command T (t) at the time of magnetic pole detection is assumed to have an amplitude close to zero at the start of the measurement step S3, and the amplitude gradually and monotonically increases until time t = 0.25 seconds. Function.
The slip command generated in the slip command generation step S2 is a function having a change of electrical angle ½ rotation in 0.5 seconds of ω (t) = 2πt, and the continuation condition of step S35 is 0 ≦ t ≦ 0.75.
FIG. 3 shows an electromagnetic force command T (t) during magnetic pole detection, exciting currents iu (t), iu (t) and iw (t) energized in the three-phase windings of the U, V and W phases, The speed state quantity v (t) and the position state quantity x (t) of the mover at the time are shown by time series data, and FIG. 4 is an enlarged partial time of FIG.
The magnetic force detection electromagnetic force command T (t) has a waveform as shown in FIG. 3A and FIG. 4A, and its amplitude gradually decreases between 0 seconds and 0.25 seconds indicated by the arrow A part. Monotonically increasing.
In the measurement step S 3, the current converter 114 converts the magnetic force detection time electromagnetic force command T (t) and the electrical angle command Ψ (t) = ω (t) + Φ (t) into the excitation current 102.
The excitation current 102 is iu (t) = T (t) * sin (Ψ (t)), iv (t) = T (t) * sin (Ψ (t) + 2π / 3), iw (t) = T ( t) is generated based on * sin (Ψ (t) + 4π / 3), and the waveforms are as shown in FIGS. 3B and 4B.
When this exciting current 102 is energized, the speed state quantity v (t) of the mover becomes a waveform as shown in FIGS. 3C and 4C, and the position state quantity x (t) of the mover is The waveforms are as shown in 3 (d) and FIG. 4 (d).
As shown in FIG. 3D, when the mover does not move greatly, the armature position state quantity Φ (t) is much smaller than the slip command ω (t). Ψ (t) is substantially equal to the slip command ω (t).
Here, in 0.5 seconds from 0.25 seconds to 0.75 seconds, the slip command ω (t) has a change of an electrical angle of 1/2 rotation or more. An electrical angle command that includes the strongest electromagnetic force with respect to T (t) is included. That is, it can be seen that the electromagnetic force is strongest in the vicinity of the arrow B in FIG. 3 where the amplitude of the speed state quantity v (t) is maximum.
In the magnetic pole offset amount calculation step S4, when the response ratio req (t) is calculated by the method 5 in step S42, for example, the waveform thereof is as shown in FIG. Further, reqmax is set to the maximum positive or negative value of the response ratio req (t) in the time interval 0.25 ≦ t ≦ 0.75, and reqmax × cos (ω (t) −θ ′) − req (t) When the absolute value is an evaluation amount, this evaluation amount is integrated in a time interval 0.25 ≦ t ≦ 0.75, and a value of θ ′ that minimizes the integrated value is calculated, an integrated value for θ ′ The change is as shown in FIG. That is, in FIG. 5B, as indicated by the arrow D, it means that the integral value is minimum at θ ′ = 0.278π (= 41 degrees), and the function reqmax × Since cos (ω (t) −0.2278π) has a waveform close to the response ratio req (t), the magnetic pole offset amount to be identified may be θ = 0.2278π (= 41 degrees). .
In this experiment, the accuracy of magnetic pole detection is identified within ± 1 degree in electrical angle, and sufficiently satisfies the required accuracy of magnetic pole detection (within ± 7 degree). Further, the position state quantity x (t) of the mover has a maximum change of 71 μm as indicated by the arrow C in FIG. 3. If this change is such a level, the control object operated by the motor is an obstacle. The possibility of coming into contact with such is extremely low.
[0033]
[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, about the thing which has the same function as description of 1st Example, the same code | symbol is attached | subjected and description is abbreviate | omitted.
FIG. 6 shows the results when the magnetic pole detection operation is performed based on the second embodiment of the present invention in time series data, and FIG. 7 is an explanatory diagram showing the results of identifying the magnetic pole offset amount.
The configuration of the motor control device and the flow of the magnetic pole detection operation in the second embodiment are the same as those in FIG. 1 or FIG.
The second embodiment is an example when the cable connected to the mover has a large cable tension. As in the first embodiment, the speed state quantity v (t) is measured in step S34. As a result, the speed state quantity v (t) of the mover changes at an indefinite speed as shown in FIG. is doing.
Therefore, in such a case, prior to the magnetic pole offset amount calculation step S4, the speed state quantity v (t) (described above) is applied to a filter that removes frequency components other than the period of the magnetic force detection electromagnetic force command T (t). In the case where the response ratio req (t) is calculated by the method 3 and the method 6 described above, the corrected speed state quantity v ′ (t) through which the “position state quantity x (t)” (hereinafter the same applies) is passed (the method described above) For example, when the response ratio req (t) is calculated by 3 or 6, “correction position state quantity x ′ (t)” (the same applies hereinafter) is calculated, and the value of the speed state quantity v (t) is corrected to this value. It may be replaced with the value of the speed state quantity v ′ (t).
Specifically, in order to remove frequency components other than the period (400 Hz) of the electromagnetic force command T (t) at the time of magnetic pole detection, first, the speed state quantity v (t) is passed through a high-pass filter, and the speed offset component is set. remove. Next, the velocity state quantity v (t) is subjected to Fourier transform (FFT), and then components other than the cycle of the magnetic force detection electromagnetic force command T (t) are cut from the spectrum to perform inverse Fourier transform (Inverse FFT). Thus, the corrected speed state quantity v ′ (t) may be calculated. As a result, the corrected speed state quantity v ′ (t) is as shown in FIG.
After replacing the value of the speed state quantity v (t) with the value of the corrected speed state quantity v ′ (t), for example, the result of calculating the response ratio req (t) by the method 5 is shown in FIG. ), The response ratio req (t) becomes maximum when the armature position state quantity Φ (t) and the slip angle ω coincide with each other, and the armature position state quantity Φ (t) and the slip angle When ω is deviated by ± π / 2 in electrical angle, it becomes zero, and when the armature position state quantity Φ (t) and slip angle ω are deviated by electrical angle by π, the property is minimized. To have. Similarly to the first embodiment, reqmax is the maximum positive or negative value of the response ratio req (t) in the time interval 0.25 ≦ t ≦ 0.75, and reqmax × cos (ω (t) −θ ′) When the absolute value of −req (t) is used as an evaluation amount, and this evaluation amount is integrated over a time interval of 0.25 ≦ t ≦ 0.75, a value of θ ′ that minimizes the integrated value is calculated. , Θ ′ is as shown in FIG. 7B. That is, in FIG. 7B, it means that the integral value is minimum at θ ′ = 1.77878 (= 320 degrees) as indicated by the arrow E, and the function reqmax × shown in FIG. Since cos (ω (t) −1.778π) has a waveform close to the response ratio req (t), the magnetic pole offset amount to be identified may be θ = 1.77878π (= 320 degrees). .
[0034]
In this way, by removing frequency components other than the period of the magnetic force command T (t) at the time of magnetic pole detection from the velocity state variable v (t) or the position state variable x (t), the electromagnetic force command T at the time of magnetic pole detection. The response ratio req (t) of the mover position, velocity or acceleration state quantity with respect to (t) is maximized when the armature position state quantity Φ (t) and the slip angle ω coincide with each other. When the child position state quantity Φ (t) and the slip angle ω are deviated by ± π / 2 in electrical angle, it becomes zero, and the armature position state quantity Φ (t) and the slip angle ω are deviated by π in electrical angle. In this case, the magnetic pole can be detected with high accuracy. Even when the mover is operating at the time of magnetic pole detection, magnetic pole detection can be performed in a short time and with high accuracy.
[0035]
In addition, a delay occurs between the exciting current 103 and the electromagnetic force command T (t) at the time of magnetic pole detection due to the winding resistance and reactance of the electric motor 103, and this delay time of the electromagnetic force command T (t) at the time of magnetic pole detection. When the value is larger than the period, the phase difference between the electromagnetic force actually acting on the mover and the electromagnetic force command T (t) at the time of magnetic pole detection becomes large, and the response ratio req ( An error is included in the value of t).
Therefore, in such a case, prior to the magnetic pole offset amount calculation step S4, a corrected magnetic pole detection electromagnetic force command T ′ (t) obtained by adding a delay time to the magnetic pole detection electromagnetic force command T (t) is calculated. Then, the electromagnetic force command T (t) at the time of magnetic pole detection may be replaced with the value of the electromagnetic force command T ′ (t) at the time of correction magnetic pole detection.
Specifically, when R is a winding resistance [Ω] and L is a reactance [H], for example, the delay time is represented by a time constant of te = L / R [seconds]. A value obtained by transmitting the electromagnetic force command T (t) at the time of magnetic pole detection to a primary delay filter or the like may be set as the electromagnetic force command T ′ (t) at the time of detecting the magnetic pole.
Thus, since the accuracy of the response ratio req (t) is increased by giving a delay time to the electromagnetic force command T (t) during magnetic pole detection, the magnetic pole can be detected with high accuracy.
[0036]
In the second embodiment, an example is described in which the speed state quantity v (t) includes an indefinite speed component due to the influence of the cable tension or the like. It goes without saying that it is effective against any disturbances such as linear and non-linear frictional forces and torque ripples.
[0037]
[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIG. In addition, about the thing which has the same function as description of 1st Example or 2nd Example, the same code | symbol is attached | subjected and description is abbreviate | omitted.
FIG. 8 is a flowchart showing the flow of magnetic pole detection operation in the third embodiment of the present invention.
The configuration of the motor control device in the third embodiment is the same as that shown in FIG.
The magnetic pole detection operation is performed by the magnetic pole offset amount identifier 117 according to the flowchart shown in FIG.
The electromagnetic force command generation step S1, the slip command generation step S2, and the measurement step S3 are performed in the same procedure as in the first embodiment or the second embodiment.
In addition to steps S41 and S42 described in the first embodiment, step S43, step S44 and step S45 are added to the magnetic pole offset amount calculating step S4.
Step S43 is performed prior to step S41, and the mover state quantity is determined. That is, when the value of the state quantity of the mover is zero or extremely small, it is determined as “No”, otherwise it is determined as “Yes”, and when it is determined as “No”, Step S45 is performed. If it is determined to be acceptable, the process proceeds to step S41.
Step S44 is performed prior to step S42, and the response ratio req (t) is determined. That is, if the value of the response ratio req (t) is zero or an extremely small value, it is determined as “No”, otherwise it is determined as “Yes”, and if it is determined as “No”, the process proceeds to Step S45. If it is determined, the process proceeds to step S42.
Step S45 generates a magnetic pole detection electromagnetic force command T (t) as in the electromagnetic force command generation step S1. That is, it is regenerated so that the amplitude of the electromagnetic force command T (t) at the time of magnetic pole detection is increased, or is regenerated so that the period of the electromagnetic force command T (t) at the time of magnetic pole detection is shortened or lengthened. Proceed to
This means is extremely effective in an electric motor in which external forces such as cable tension, friction, and cogging force change according to the position of the mover of the electric motor at the start. The electromagnetic force command T (t) at the time of magnetic pole detection is set to a sufficiently small amplitude or a sufficiently short period to cope with a case where the external force is small, and a sufficient speed cannot be detected or the magnetic pole offset amount with a small amplitude or a short period. If there is a possibility that θ cannot be identified, the amplitude may be increased or the period may be set longer each time step S45 is passed.
[0038]
As described above, when the speed state quantity v (t) is measured in the measurement step S3, if the value of the mover state quantity is zero or extremely small, or in the magnetic pole offset quantity calculation step S4, the response ratio req As a result of calculating (t), when the value of the response ratio req (t) is zero or extremely small, the process returns to the electromagnetic force command generation step S1, and the magnetic force detection time electromagnetic force command T (t) By generating again the amplitude so as to increase or by generating again the cycle of the electromagnetic force command T (t) at the time of detecting the magnetic pole to be shorter or longer and performing the measurement step S3 again, the mover becomes larger than necessary. Magnetic pole detection can be performed with high accuracy without operation.
[0039]
[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIGS. In addition, about the thing which has the same function as description from 1st Example to 3rd Example, the same code | symbol is attached | subjected and description is abbreviate | omitted.
FIG. 9 is a block diagram showing the configuration of the motor control apparatus according to the fourth embodiment of the present invention.
FIG. 10 is a flowchart showing the flow of magnetic pole detection operation in the fourth embodiment of the present invention.
The configuration of the motor control apparatus in the fourth embodiment is as shown in FIG. 9 and includes a display 121 in addition to the configuration of FIG. The magnetic pole offset amount identifier 117 has a function of outputting an error signal 122 in an error state to be described later to stop the magnetic pole detection operation, and the display device 121 has a function of outputting the error state to the outside based on the error signal 122. .
The magnetic pole detection operation is performed by the magnetic pole offset amount identifier 117 according to the flowchart shown in FIG.
The electromagnetic force command generation step S1, the slip command generation step S2, and the measurement step S3 are performed in the same procedure as in the first to third embodiments.
The magnetic pole offset amount calculating step S4 includes steps S41, S42 described in the first embodiment, and step S45 described in the second embodiment, and replaces steps S43 and S44 described in the third embodiment. S43 'and step S44' are added.
Step S43 ′ is performed prior to step S41, and the mover state quantity is determined. In other words, if the value of the state quantity of the mover's position, velocity or acceleration is zero or extremely small, it is judged as no, and if the value of the state quantity is abnormally small or large, it is abnormal. If it is determined to be negative, it is determined to be acceptable. If it is determined to be negative, the process proceeds to step S45. If it is determined to be abnormal, the magnetic pole detection operation is stopped as an error state. Proceed to step S41.
Step S44 ′ is performed prior to step S42, and the response ratio req (t) is determined. That is, it is determined that the case where the value of the response ratio req (t) is zero or extremely small is determined as “no”, and the case where the value of the response ratio req (t) is abnormally small or large is determined as abnormal. In other cases, it is determined to be acceptable, and if it is determined to be negative, the process proceeds to step S45. If it is determined to be abnormal, an error state is set, and the magnetic pole detection operation is stopped. Proceed to step S42.
In addition, in step S43 ′, the state of the mover, the state of velocity or acceleration is subjected to frequency analysis by means such as FFT, and the magnetic force command T (t) for detecting the magnetic pole out of the spectrum obtained from the frequency analysis result. If there is a peak different from the period, a procedure for determining an abnormality may be added.
This means is extremely effective in an electric motor in which an external force such as cable tension or cogging force of the mover changes according to the mover position of the electric motor at the time of starting. It is suitable for detecting abnormalities such as a state where the control object of the electric motor is in contact with an obstacle.
[0040]
As described above, when the speed state quantity v (t) is measured in the measurement step S3, when the value of the mover state quantity is abnormally small or large, or in the magnetic pole offset quantity calculation step S4, the response As a result of calculating the ratio req (t), when the value of the response ratio req (t) is abnormally small or large, or by analyzing the frequency of the position, velocity or acceleration state quantity of the mover, In the spectrum obtained from the frequency analysis results, if there is a peak that is different from the period of the electromagnetic force command T (t) at the time of magnetic pole detection, an error state occurs and the magnetic pole detection operation is stopped, so that abnormal operation occurs in actual operation. Stable control can be expected without presenting any abnormalities, such as abnormalities in the motor or control device prior to the actual operation, or abnormalities such as the state where the controlled object of the motor is in contact with an obstacle. If there is it can be quickly detected the abnormality, motor and safety of the controlled object can be secured.
[0041]
[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described with reference to FIGS. In addition, about the thing which has the same function as description from 1st Example to 4th Example, the same code | symbol is attached | subjected and description is abbreviate | omitted.
FIG. 11 is a block diagram showing the configuration of the motor control apparatus according to the fifth embodiment of the present invention.
FIG. 12 is a flowchart showing the flow of magnetic pole detection operation in the fifth embodiment of the present invention.
The configuration of the motor control device in the fifth embodiment is as shown in FIG. 11. In addition to the configuration of FIG. 9, the feedback controller 111 outputs an error signal 123 in the error state described later and stops the actual operation. The display device 121 has a function of outputting an error state to the outside based on the error signal 123.
The magnetic pole detection operation and the actual operation are performed by the magnetic pole offset amount identifier 117 and the feedback controller 111 according to the flowchart shown in FIG.
The electromagnetic force command generation step S1, the slip command generation step S2, the measurement step S3, and the magnetic pole offset amount calculation step S4 are performed in the same procedure as in the first to fourth embodiments.
In order to perform the steps S1 to S4 a plurality of times, the repetition determination is performed in the repetition determination S5. In this way, by repeatedly performing steps S1 to S5, a plurality of magnetic pole offset amounts θ are identified. In the variation determination S6, variations in the plurality of magnetic pole offset amounts θ are determined. When the variation is large, the magnetic pole detection operation is stopped as an error state, and when the variation is small, the magnetic pole detection operation is terminated and the actual operation is started.
[0042]
For a while after the actual operation is started, the armature position state quantity Φ (t) or the speed state quantity v (t) is monitored. Specifically, after performing step S7 for performing feedback control calculation, step S8 for measuring the armature position state quantity Φ (t) or the speed state quantity v (t) is performed, and monitoring determination is performed in step S9.
In step S9, if the time has reached a certain time, it is determined that the monitoring is finished, and if the time has not reached a certain state, it is determined that the monitoring is continued, and the mover operates in the direction opposite to the electromagnetic force command. Is judged abnormal, and if it is judged that monitoring has ended, it exits this monitoring state and continues actual operation, and if it is judged abnormal, it stops the actual operation as an error state and it is judged that monitoring is to be continued Advances to step S7.
This means is extremely effective in an electric motor in which an external force such as cable tension or cogging force changes according to the position of the mover of the electric motor at the start. It is suitable for detecting an abnormality such as a state where the control object is in contact with an obstacle.
[0043]
As described above, the procedure from the electromagnetic force command generation step S1 to the magnetic pole offset amount calculation step S4 is performed a plurality of times to calculate a plurality of magnetic pole offset amounts. By canceling the magnetic pole detection operation, stable control can be expected without exhibiting abnormal operation in actual operation, and motor or control device abnormality prior to actual operation, or the controlled object of the motor is an obstacle If there is an abnormality such as a state of being in contact with the motor, the abnormality can be detected promptly, and the safety of the electric motor and its controlled object is ensured. In addition, when performing actual operation after performing magnetic pole detection operation, the armature position state quantity Φ (t) or the speed state quantity v (t) is monitored for a while after the actual operation is started. If the mover moves in the opposite direction to the electromagnetic force command, it will be in an error state, and even if the abnormal operation is exhibited in the actual operation, the abnormality can be detected quickly by stopping the actual operation. This ensures the safety of the electric motor and its control device.
[0044]
The motors shown in the first to fifth embodiments were linear motors having three-phase windings of U, V and W phases. Needless to say, it can be applied to electric motors. Further, the configuration of the control device does not have to be constrained by the configuration of FIG. 1, FIG. 9, or FIG. 11, and may have any configuration as long as it has a similar function.
[0045]
【The invention's effect】
According to the motor control method of the present invention, the magnitude of the current to be energized is determined in proportion to the electromagnetic force command, and the electrical angle command for the current is determined based on the armature position state quantity of the mover to perform excitation. In the electric motor control method for generating an electric current and generating an electromagnetic force by energizing the exciting current, when the magnetic pole offset amount θ of the electric motor is identified before actual operation of the electric motor, the electric machine at time t An electromagnetic force command generation step S1 for generating a magnetic pole detection electromagnetic force command T (t) by a periodic function having a short period when the child position state quantity is Φ (t) and the electrical angle command is ψ (t). The slip command generation step S2 for generating a slip command ω (t) that changes within a certain range with the lapse of time t and the magnetic force detection time T electromagnetic force command T (t) for a predetermined time. The magnitude of the current to be energized is determined, and the electrical angle command ψ (t) is determined based on the armature position state quantity Φ (t) and the slip command ω (t) to generate an excitation current. Then, an electromagnetic force is generated by energizing this exciting current, and the measurement step S3 for measuring the velocity state quantity v (t) of the movable element during the predetermined time, and the position, velocity or acceleration of the movable element are determined. As a state quantity, a response ratio req (t) is calculated from a ratio of the state quantity to the magnetic force detection electromagnetic force command T (t), and the response ratio req (t) and the slip command ω (t) are calculated. The magnetic pole detection operation is performed in accordance with the procedure of the magnetic pole offset amount calculation step S4 for comparing and identifying the magnetic pole offset amount θ. In actual operation, the magnitude of the current to be supplied is proportional to the electromagnetic force command. Determine the power Based on the child position state quantity Φ (t) and the magnetic pole offset quantity θ, the electrical angle command ψ (t) is determined to generate an excitation current, and an electromagnetic force is generated by applying the excitation current. Therefore, without using a magnetic pole position sensor, absolute value encoder or current detector, without moving the mover greatly when detecting the magnetic pole, and conversely, when the mover is moving when detecting the magnetic pole However, it is possible to provide an electric motor control method and a control device thereof that can detect magnetic poles in a short time and with high accuracy.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of a motor control apparatus according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing a flow of magnetic pole detection operation in the first embodiment of the present invention.
FIG. 3 is a time-series data showing a result when a magnetic pole detection operation is performed based on the first embodiment of the present invention.
FIG. 4 is a time-series data showing the results when the magnetic pole detection operation is performed based on the first embodiment of the present invention, and is a partial enlargement of FIG. 3;
FIG. 5 is an explanatory diagram showing the result of identifying the magnetic pole offset amount based on the first embodiment of the present invention.
FIG. 6 shows time-series data of results when a magnetic pole detection operation is performed based on the second embodiment of the present invention.
FIG. 7 is an explanatory diagram showing a result of identifying a magnetic pole offset amount.
FIG. 8 is a flowchart showing a flow of magnetic pole detection operation in the third embodiment of the present invention.
FIG. 9 is a block diagram showing a configuration of a motor control device according to a fourth embodiment of the present invention.
FIG. 10 is a flowchart showing a flow of magnetic pole detection operation in the fourth embodiment of the present invention.
FIG. 11 is a block diagram showing a configuration of a motor control apparatus according to a fifth embodiment of the present invention.
FIG. 12 is a flowchart showing a flow of magnetic pole detection operation in the fifth embodiment of the present invention.
FIG. 13 is an explanatory diagram showing a first conventional example.
FIG. 14 is a flowchart showing a flow of a second conventional example.
FIG. 15 shows time-series data of an excitation current and a mover speed that appear when a sine wave that is energized as an excitation current has a high frequency and magnetic pole detection is performed based on the first conventional example.
[Explanation of symbols]
101 Control device
102 Excitation current
103 electric motor
104 Speed detector
107 integrator
108 Target value
110 Electromagnetic force command
111 Feedback controller
112 Electromagnetic force command changer
113 Electrical angle switch
114 Current converter
115 adder
117 Magnetic pole offset amount identifier
121 Display
122, 123 Error signal
v (t) Speed state quantity
Φ (t) Armature position state quantity
θ Magnetic pole offset
Ψ (t) Electrical angle command
T (t) Magnetic force command when detecting magnetic pole
ω (t) Slip command

Claims (24)

The magnitude of the current to be energized is determined in proportion to the electromagnetic force command, the electrical angle command for the current is determined based on the armature position state quantity of the mover, and an excitation current is generated. In a control method of an electric motor that generates electromagnetic force by energization,
When identifying the magnetic pole offset amount θ of the motor before actual operation of the motor, when the armature position state quantity at time t is Φ (t) and the electrical angle command is ψ (t),
An electromagnetic force command generation step S1 for generating an electromagnetic force command T (t) at the time of magnetic pole detection by a periodic function having a short period;
A slip command generation step S2 for generating a slip command ω (t) that changes within a certain range as time t passes;
During a predetermined time, the magnitude of the current to be supplied is determined so as to be proportional to the electromagnetic force command T (t) at the time of magnetic pole detection, and the armature position state quantity Φ (t) and the slip command ω (t) The electrical angle command ψ (t) is determined based on the following to generate an excitation current, and an electromagnetic force is generated by energizing the excitation current, and the velocity state quantity v of the mover during the predetermined time A measurement step S3 for measuring (t);
A response ratio req (t) is calculated from a ratio of the state quantity to the electromagnetic force command T (t) at the time of detecting the magnetic pole, using the position, velocity or acceleration of the mover as a state quantity, and this response ratio req (t) And the slip command ω (t) to identify the magnetic pole offset amount θ, and a magnetic pole offset amount calculating step S4,
The magnetic pole detection operation is performed according to the procedure
In actual operation, the magnitude of the current to be supplied is determined in proportion to the electromagnetic force command, and the electrical angle command ψ is determined based on the armature position state quantity Φ (t) and the magnetic pole offset quantity θ. (T) is determined, an exciting current is generated, and an electromagnetic force is generated by energizing the exciting current. 2. The motor control according to claim 1, wherein the period of the electromagnetic force command T (t) at the time of detecting the magnetic pole is 2n times the control calculation period of the control device (where n is a natural number). Method. 3. The motor control method according to claim 1, wherein the electromagnetic force command T (t) at the time of detecting the magnetic pole is a periodic function such as a trapezoidal wave, a rectangular wave, a triangular wave, or a sine wave. The electromagnetic force command T (t) at the time of magnetic pole detection is assumed to be a function whose amplitude is close to zero at the start of the measurement step S3 and whose amplitude gradually increases monotonously until a certain time is reached. The method for controlling an electric motor according to any one of claims 1 to 3, wherein: The electromagnetic force command T (t) at the time of detecting the magnetic pole is assumed to be a function whose amplitude is close to zero at the end of the measurement step S3 and whose amplitude gradually decreases monotonously after reaching a certain time. The method for controlling an electric motor according to claim 1, wherein: 6. The electric motor according to claim 1, wherein the slip command ω (t) is a function having a change of at least an electrical angle of 1/2 rotation or more during the predetermined time. Control method. In the magnetic pole offset amount calculating step S4,
The response ratio req (t) is defined only at time t when the magnetic force detection electromagnetic force command T (t) becomes an extreme value, and the first-order derivative of the speed state quantity v (t) near the time t. When the time when the value dv (t) / dt takes an extreme value is t ′,
req (t) = (dv (t ′) / dt) / T (t)
The motor control method according to claim 1, wherein the motor control method is calculated by: In the magnetic pole offset amount calculating step S4,
The response ratio req (t) is defined only at time t when the first-order integral value ST (t) of the electromagnetic force command T (t) at the time of magnetic pole detection becomes an extreme value, and the speed state is near the time t. When the time when the amount v (t) takes an extreme value is t ′,
req (t) = v (t ′) / ST (t)
The motor control method according to claim 1, wherein the motor control method is calculated by: Prior to the magnetic pole offset amount calculating step S4, a position state amount x (t) obtained by integrating the speed state amount v (t) is calculated, and in the magnetic pole offset amount calculating step S4,
The response ratio req (t) is defined only at time t when the second-order integral value SST (t) of the electromagnetic force command T (t) at the time of magnetic pole detection becomes an extreme value, and the position state is near the time t. When the time at which the quantity x (t) takes an extreme value is t ′,
req (t) = x (t ′) / SST (t)
The motor control method according to claim 1, wherein the motor control method is calculated by: In the magnetic pole offset amount calculating step S4,
The response ratio req (t) is defined only at time t when the magnetic force detection electromagnetic force command T (t) becomes an extreme value, and the first-order derivative of the speed state quantity v (t) near the time t. In a time domain in which the value dv (t) / dt has the same sign, a value obtained by integrating the first-order differential values dv (t) / dt is defined as Sdv (t).
req (t) = Sdv (t) / T (t)
The motor control method according to claim 1, wherein the motor control method is calculated by: In the magnetic pole offset amount calculating step S4,
The response ratio req (t) is defined only at time t when the first-order integral value ST (t) of the electromagnetic force command T (t) at the time of magnetic pole detection becomes an extreme value, and the speed state is near the time t. In the time domain where the amount v (t) has the same sign, the value obtained by integrating the speed state amount v (t) is Sv (t).
req (t) = Sv (t) / ST (t)
The motor control method according to claim 1, wherein the motor control method is calculated by: Prior to the magnetic pole offset amount calculating step S4, a position state amount x (t) obtained by integrating the speed state amount v (t) is calculated. In the magnetic pole offset amount calculating step S4, the response ratio req (t ) Is defined only at time t when the second-order integral value SST (t) of the electromagnetic force command T (t) at the time of magnetic pole detection becomes an extreme value, and the position state quantity x (t) is near the time t. In the time domain having the same sign, a value obtained by integrating the position state quantities x (t) is defined as Sx (t).
req (t) = Sx (t) / SST (t)
The motor control method according to claim 1, wherein the motor control method is calculated by: In the magnetic pole offset amount calculating step S4, the maximum value of the absolute value | req (t) | of the response ratio or the average value of the absolute value | req (t) | When the value multiplied by 2 is reqmax, the absolute value, squared value, etc. of reqmax × cos (ω (t) −θ ′) − req (t) is used as the evaluation amount, and this evaluation amount is obtained during the predetermined time. The value of θ ′ is calculated such that the value obtained by integrating the values becomes the minimum, and this value θ ′ is set as the magnetic pole offset amount θ. Control method. Prior to the magnetic pole offset amount calculation step S4, the speed state quantity v (t) or the position state quantity x (t) is applied to a filter that removes frequency components other than the period of the magnetic force detection electromagnetic force command T (t). ) Through which the corrected speed state quantity v ′ (t) or the corrected position state quantity x ′ (t) is calculated, and the value of the speed state quantity v (t) or the position state quantity x (t) is calculated. The motor control method according to any one of claims 1 to 13, wherein the value is replaced with a value of a corrected speed state quantity v '(t) or a corrected position state quantity x' (t). If there is a delay time between the excitation current and the magnetic force detection electromagnetic force command T (t), the magnetic force detection electromagnetic force command T (t) is set prior to the magnetic pole offset amount calculating step S4. An electromagnetic force command T ′ (t) at the time of detection of the correction magnetic pole with the delay time is calculated, and the electromagnetic force command T (t) at the time of detection of the magnetic pole is calculated from the electromagnetic force command T ′ (t) at the time of correction magnetic pole detection The method for controlling an electric motor according to claim 1, wherein the value is replaced with a value. In the measurement step S3,
As a result of measuring the speed state quantity v (t), when the value of the state quantity of the mover is zero or extremely small, or in the magnetic pole offset amount calculating step S4, the response As a result of calculating the ratio req (t), when the value of the response ratio req (t) is zero or an extremely small value, the process returns to the electromagnetic force command generation step S1, and the magnetic force detection electromagnetic force command is returned. The motor control method according to any one of claims 1 to 15, wherein the measurement step S3 is performed again by regenerating the signal so that the amplitude of T (t) is increased. In the measurement step S3,
As a result of measuring the speed state quantity v (t), when the value of the state quantity of the mover is zero or extremely small, or in the magnetic pole offset amount calculating step S4, the response As a result of calculating the ratio req (t), when the value of the response ratio req (t) is zero or an extremely small value, the process returns to the electromagnetic force command generation step S1, and the magnetic force detection electromagnetic force command is returned. The motor control method according to any one of claims 1 to 16, wherein the cycle of T (t) is regenerated so as to be shortened or lengthened, and the measurement step S3 is performed again. In the measurement step S3,
As a result of measuring the speed state quantity v (t), if the value of the state quantity of the mover is abnormally small or large, or in the magnetic pole offset amount calculating step S4, As a result of calculating the response ratio req (t), if the value of the response ratio req (t) is abnormally small or large, an error state is set and the magnetic pole detection operation is stopped. A method for controlling an electric motor according to any one of claims 1 to 17. In the measurement step S3,
After the velocity state quantity v (t) is measured, the state quantity of the position, velocity or acceleration of the mover is subjected to frequency analysis, and the magnetic force detection electromagnetic force command T ( 19. The motor control method according to claim 1, wherein when there is a peak different from the period of t), an error state is set and the magnetic pole detection operation is stopped. The procedure from the electromagnetic force command generation step S1 to the magnetic pole offset amount calculation step S4 is performed a plurality of times to calculate a plurality of the magnetic pole offset amounts, and when the variation of the magnetic pole offset amount is large, an error state is set. The motor control method according to any one of claims 1 to 19, wherein the magnetic pole detection operation is stopped. When performing actual operation after performing the magnetic pole detection operation,
For a while after the actual operation is started, the armature position state quantity Φ (t) or the speed state quantity v (t) is monitored, and the mover moves in the direction opposite to the electromagnetic force command. 21. The method for controlling an electric motor according to any one of claims 1 to 20, wherein when the motor is operated, an error state is set and the actual operation is stopped. An integrator that integrates the speed state quantity output from the speed detector of the motor and converts it into an armature position state quantity; and an electromagnetic force command based on the target value and the armature position state quantity and / or the speed state quantity A feedback controller, an electromagnetic force command switcher, an electrical angle switcher, a current converter, an adder, and a magnetic pole offset amount identifier,
When identifying the magnetic pole offset amount of the motor before actual operation of the motor, first, the integrator value is cleared, and the magnetic force detection time electromagnetic force command output from the magnetic pole offset amount identifier is the electromagnetic force. A slip command that is input to the current converter via the command switch and output from the magnetic pole offset amount identifier is input to the adder together with the armature position state quantity via the electrical angle switch. The adder calculates the sum of the input armature position state quantity and the slip command and outputs an electrical angle command, and the current converter energizes the current so as to be proportional to the electromagnetic force command when detecting the magnetic pole. Is determined, and an excitation current is output based on the electrical angle command, and the magnetic pole offset identifier identifies the magnetic pole offset as a state in which the velocity state quantity is input. It performs the magnetic pole detection operation to identify,
In actual operation, the electromagnetic force command output from the feedback controller is input to the current converter via the electromagnetic force command switch, and the magnetic pole offset amount output from the magnetic pole offset amount identifier Is input to the adder together with the armature position state quantity via the electrical angle switch, and the adder calculates the sum of the input armature position state quantity and the magnetic pole offset quantity to calculate an electrical angle command. Is output, and the current converter determines the magnitude of the current to be supplied in proportion to the electromagnetic force command, and outputs an excitation current based on the electrical angle command. The magnetic pole offset amount identifier has a function of outputting an error signal to stop the magnetic pole detection operation when the error state occurs, and further, an indicator that outputs the error state externally based on the error signal. The motor control device according to claim 22, wherein the motor control device is provided inside. The feedback controller has a function of outputting an error signal to stop the actual operation when the error state occurs, and further includes an internal display for outputting the error state based on the error signal. 24. The motor control device according to claim 22 or 23.

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