JP2812856B2 - Control method of linear motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a linear motor, and more particularly, to a method for controlling a DC linear motor.

[0002]

2. Description of the Related Art A DC linear motor by self-control is
The thrust can be controlled by any one of the field strength, the ground armature coil current, and the commutation phase of the inverter, which are control systems on the vehicle.

[0003] Further, since the DC linear motor is basically a ground control system, it is considered preferable to control the thrust by the ground armature coil current and the commutation phase of the inverter.

FIG. 6 is a block diagram of thrust control by current control of a DC type linear motor, wherein 1 is a forward converter which is a DC constant current converter, 2 is an inverter which is an inverse converter,
3 is a ground armature coil. The forward converter 1 controls the DC output current as a variable constant current in accordance with the thrust control command, and the inverter 2 controls the variable current from the forward converter 1 based on the phase position detection signal to control the ground armature coil 3. Supply alternating current.

FIG. 7 shows thrust control by phase control of a DC linear motor. A constant current is supplied from a forward converter 1 to an inverse converter 2. The phase controller 4 generates a phase signal based on the thrust control command and the position detection signal, and supplies the phase signal to the inverse converter 2 to execute thrust control by phase control.

Here, the thrust of the DC linear motor basically depends on the control angle and not on the speed. Therefore, in order to perform the constant speed operation, it is necessary to detect a difference from the target speed and perform thrust control by a closed loop.

As shown in FIG. 8, in a system called a self-control system, a commutation phase angle is set to 0 during acceleration, −π during deceleration, and −π during coasting in order to obtain the maximum thrust.
/ 2, so that thrust can be obtained efficiently with as little current as possible. The DC current generated by the forward converter 1 is commutated by the inverse converter 2 to drive the DC linear motor. It is a method to do.

[0008]

In the speed control, the actual speed is detected by detecting the electric angle of the motor by detecting the electric angle of the motor by a phase detector attached to the DC linear motor and detecting the frequency of the electric angle by the speed detecting circuit. To detect. The actual speed and the set speed are amplified by the speed control amplifier and output to the forward converter as a current command value. When accelerating, the powering mode (commutation phase angle is 0) is used, and when increasing the speed, the current is increased, and when decreasing, the current is decreased.

However, the current cannot be reduced from the continuous condition to zero, and the thrust cannot be reduced to zero with this state. In order to improve this, the coasting mode (-π / 2) has been adopted. However, at present, the operation mode must be determined from the speed command value, so how to use the three modes of powering, regeneration, and coasting properly. Is getting harder. For example, when the speed command value> actual speed is set to the power running mode, and when the speed command value <actual speed is set to the regenerative mode, the coasting mode area is lost, and as shown in FIG. Will be repeated and the operation will be jerky.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. An object of the present invention is to provide a lower limiter for a current command value of a forward converter so as to control the current so as to be always continuous. The object of the present invention is to enable smooth operation of the linear motor by selecting the control phase angle of the inverter based on the command lower limit value determination signal and the speed setting level determination signal for the actual speed of the linear motor.

[0011]

According to the present invention, in order to achieve the above object , the DC power of a forward converter is controlled by an inverse converter.
Control of linear motor that drives and controls linear motor
The method includes the steps of:
The actual speed signal of the near motor is obtained, and the actual speed signal and the set speed are obtained.
Current command value based on the operation signal obtained by adding and subtracting the degree signal.
Signal, and the forward converter is controlled by the current command value signal.
And the current command value signal and the current lower limit value setting signal
Current lower limit judgment signal based on the operation signal obtained by addition and subtraction
And the actual speed signal and a predetermined speed setting level.
Speed judgment signal based on the deviation signal obtained by comparing
Based on the speed determination signal and the current lower limit value determination signal.
Select the control phase angle of the inverter according to the position signal
To change the operation mode of the linear motor to powering, coasting or rotating.
The feature is to select raw.

[0012]

The frequency of the electrical angle, which is the position signal of the linear motor, is detected by the speed detection circuit, whereby an actual speed signal is obtained. A current control circuit obtains a current command value signal based on an arithmetic signal obtained by adding and subtracting the actual speed signal and the speed setting signal, and controls the output current of the forward converter. The current command value determination circuit obtains a current command value determination signal based on an arithmetic signal obtained by adding / subtracting the current command value signal and the current command lower limit signal, and the speed determination circuit determines the actual speed signal and the speed. A speed determination signal is obtained based on a deviation signal from the set level signal. The mode selection circuit selects the commutation phase angle of the inverter according to the position signal based on the current command value determination signal and the speed determination signal, and selects the operation mode of the linear motor as powering, coasting, or regeneration.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a method for controlling a DC linear motor according to an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a rectifier which is a forward converter for converting AC to DC, and 12 denotes DC to AC. The inverter 13 is a linear motor that is a controlled part, and these form a main circuit part. In FIG. 1, reference numeral 14 denotes a position detector for detecting the position of the linear motor 13, reference numeral 15 denotes a speed detection circuit which receives an electrical angle φ which is a position detection signal of the position detection signal 14, and reference numeral 16a denotes a speed detection circuit 15. first subtraction circuit for subtracting been the actual speed signal V _R and the speed setting signal V _S of the linear motor 13 as an input, 17
Is a current control circuit for outputting a current command value signal I _C as input arithmetic output signal of the first adder circuit 16a. 1
Second subtraction circuit 6b is added to or subtracted based on the current command value signal I _C and the current command limit value signal I _L of the current control circuit 17,
Reference numeral 18 denotes a current command value determination circuit that determines a current command value by using an operation signal of the second addition / subtraction circuit 16b as an input. 19
Comparator for comparing an input the actual speed signal _{V R} and the speed set level signal _V L of the velocity detection circuit _{15 (V 1, V 2,} V 3, V 4) , the 20 inputs a differential output signal of the comparator circuit 19 A speed judgment circuit for outputting a speed judgment signal as a reference signal;
Is a mode selection circuit for selecting a mode by using the determination signal of the above as an input.

In the above configuration, the inverter 12 is driven by supplying AC power to the linear motor 13 with the DC output of the rectifier 11 as an input. The position detector 14 inputs a position detection signal of the linear motor 13 to the speed detection circuit 15 and the mode selection circuit 21. The speed detection circuit 15 detects the actual speed of the linear motor 13 by detecting the frequency of the electrical angle φ as the position detection signal. The actual speed signal V _R detected by the velocity detection circuit 15 first subtraction circuit 16a
In the speed setting level signal V _S addition and subtraction, the operation signal is inputted to the current control circuit 17. Controlling the rectifier 11 by a current command value signal I _C of the current control circuit 17.

Further, the current command value signal I _C is subtraction and the current lower limit value setting signal I _L by the second subtraction circuit 16b, the operation signal is inputted to the current command value determination circuit 18. The current command value judging circuit 18 is the second addition / subtraction circuit 16
A current command value determination signal is input to the mode selection circuit 21 based on the calculation signal of b.

Furthermore, in the comparison circuit 19, the actual speed signal _{V R} and the speed set level signal _V L _(V 1 ~V ₄₎ are compared, the deviation signal is input to the speed determination circuit 20. The speed determination circuit 20 inputs a speed determination signal to the mode selection circuit 21 based on the deviation signal.

The mode selection circuit 21 receives the position detection signal of the position detector 14 as an input, and based on the current command value determination signal from the current command value determination circuit 18 and the speed determination signal from the speed determination circuit 20, Commutation phase angle 0, -π /
2, -π is selected, and the powering mode, the regenerative mode, and the coasting mode are selected.

During power running and regeneration, the thrust of the linear motor 13 cannot be reduced to zero, so that it is necessary to shift to the coasting mode. As a condition for this, the current command value is set to the lower limit _IL or less. Further, the four levels of _{V 1, V 2, V 3} , V 4 as _{V L} as shown in FIG. 2 in the comparison circuit 19 is provided, these set level and speed determination circuit 20
Is input to the mode selection circuit 21.

In the mode selection circuit 21, the commutation phase angle of the inverter 12 is fixed to three points of 0, -π / 2 and -π, and a mode is selected according to the current command value judgment signal and the speed judgment signal. Control the inverter. Set the two levels _{V 1} and _{V 4} as shown in FIG. 2 with respect to the set speed _{V S,}
These if the actual velocity V _R is V ₁ or less relative to the level powering mode (commutation phase angle 0), when the V ₄ or more selectively irrespective of the current command value regeneration mode (- [pi]) .

Furthermore, by providing a coasting mode (- [pi] / 2) as an intermediate mode power running mode and regeneration mode, the speed at powering mode speed V ₂ in the case or regenerative mode V ₃ or more
Hereinafter, and when the current command value is less than the lower limit value I _L shifts to the coasting mode.

[0022] That is, as shown in FIG. 3, the actual speed _{V R}
There have been follow-up to the speed setting value V _S, too raise the actual speed V _R and the transition to coasting mode and become V _3, the fall and the power running mode again this by up to V _1. Further, as shown in FIG. 4, if the actual speed V _R follows the set speed V _S, does not inadvertently mode transition even if overshoot has hunting tracking performance. Furthermore, as shown in FIG. 5, when it becomes V ₂ or during regeneration when the actual speed V _R during power running becomes the set speed V ₃ becomes coasting mode, if the mode is shifted by overshoot, powering An extreme operation such as regenerative or regenerative to power running does not occur. Accordingly, each mode can be selected only by detecting the speed and the current command value. Moreover, since the mode always shifts via the coasting mode when shifting from power running to regeneration or from regeneration to power running, V ₁ to V ₁
It can suppress switching of unwanted modes in the range of V ₂ and _V 3 ~V _4.

[0023]

As described above, the present invention controls a forward converter based on a current command value signal, controls a current command value by providing a lower limiter so that current is always continuous, and further controls a current command value. Is the lower limit and the actual speed of the linear motor is within a predetermined set level range with respect to the set speed, and the commutation phase angle of the inverter is set to a predetermined point, for example, 0, -π / 2, Since the inverter is controlled so that the coasting mode can be obtained in the linear motor operation mode, the inverter is fixed to the three points of -π. The transition from extreme modes such as regenerative or regenerative to power running is eliminated, and the mode always shifts to coasting mode before shifting to the next mode, so that smooth operation is achieved and smooth control is performed with few mode switching. Made You.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a method for controlling a linear motor according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of setting a level of a set speed in the control method of the linear motor in FIG. 1;

FIG. 3 is a diagram showing speed characteristics and operation modes of the linear motor in the method for controlling the linear motor in FIG. 1;

FIG. 4 is a diagram showing speed characteristics and operation modes of the linear motor in the method for controlling the linear motor in FIG. 1;

FIG. 5 is a diagram showing speed characteristics and operation modes of the linear motor in the method for controlling the linear motor in FIG. 1;

FIG. 6 is a block diagram showing thrust control by current control in a conventional linear motor control method.

FIG. 7 is a block diagram showing thrust control by phase control in a conventional linear motor control method.

FIG. 8 is a thrust characteristic diagram with respect to a commutation phase angle of a forward converter in a conventional linear motor control method.

FIG. 9 is an operation mode characteristic diagram in a conventional linear motor control method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Rectifier which is a forward converter 12 ... Inverter which is an inverse converter 13 ... Linear motor 14 ... Position detector 15 ... Speed detection circuit 16a ... First adder / subtractor 16b ... Second adder / subtractor 17 ... Current control circuit 18 ... Current lower limit value judgment circuit 19 ... Comparator 20 ... Speed judgment circuit 21 ... Mode selection circuit

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Susumu Ozeki 2-1-17-1 Osaki, Shinagawa-ku, Tokyo Inside Meidensha Co., Ltd. (56) References JP-A-60-82090 (JP, A) JP-A-58- 6095 (JP, A) Fully open Showa 61-22197 (JP, U) Fully open show 60-128875 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02P 5/00 B60L 13 / 02-13/10

Claims (2)

(57) [Claims] 1. The DC power of a forward converter is controlled by an inverse converter.
Control of linear motor that drives and controls linear motor
The method includes the steps of:
The actual speed signal of the near motor is obtained, and the actual speed signal and the set speed are obtained.
Current command value based on the operation signal obtained by adding and subtracting the degree signal.
Signal, and the forward converter is controlled by the current command value signal.
And the current command value signal and the current lower limit value setting signal
Current lower limit judgment signal based on the operation signal obtained by addition and subtraction
And the actual speed signal and a predetermined speed setting level.
Speed judgment signal based on the deviation signal obtained by comparing
Based on the speed determination signal and the current lower limit value determination signal.
Select the control phase angle of the inverter according to the position signal
To change the operation mode of the linear motor to powering, coasting or rotating.
A linear motor control method characterized by raw selection
Law. 2. The method according to claim 1, wherein the predetermined speed setting level is set at the predetermined speed.
Speed with a value greater than the set speed around the speed
And a small value of speed, these specified speed and
Operating mode of the linear motor based on the actual speed and
Claims characterized by selecting powering, coasting or regeneration
Item 2. A method for controlling a linear motor according to Item 1.