JP3368930B2 - Servo motor regeneration processing circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo motor control device, and more particularly to a servo motor regeneration process for converting regenerative electric energy generated during operation of a servo motor into heat energy by a regenerative resistor. Circuit. 2. Description of the Related Art Conventionally, this type of servo motor regeneration processing circuit has a power transistor 3 as shown in FIG.
The regenerative voltage generated when the rotating servo motor 7 is decelerated by the electric power sent out is detected by the comparator 1, and the regenerative current is supplied to the regenerative resistor 2 via the transistor 8 to convert the regenerative electric energy into heat energy. Was consumed by doing so. [0003] The above-described conventional servo motor regeneration processing circuit, even if the servo motor is stopped when the regeneration operation is regarded as abnormal when the regeneration operation is continuously performed for a certain period of time. In the case of a sudden deceleration or a deceleration under a negative load, a large amount of regenerative energy is generated in a short time, so that there is a disadvantage that an excessive current flows to burn out the regenerative resistor and the transistor. The purpose of the present invention is
An object of the present invention is to provide a servomotor regenerative processing circuit capable of preventing burnout of a regenerative resistor or the like that occurs when the servomotor is suddenly decelerated or a negative load is applied. [0004] In the servo motor regeneration processing circuit of the present invention, the operation of the servo motor is a regeneration operation.
It is determined according to the condition shown in the following equation. Here, ω: motor rotation speed I: motor armature current R: motor armature resistance T _L : load torque ω ₀ : regenerative start motor rotation speed In the case of regenerative operation, the allowable regenerative energy P _{0 is obtained} by the following equation.
Is calculated, and Here, C: capacity of the main capacitor V _rg : regenerative processing voltage V ₀ : allowable capacity of the main circuit DC voltage at normal time : allowable energy of the regenerative resistor and the transistor
If the capacity P ₀ > 0, calculate the allowable torque T ₀ according to the following equation.
Then, Comparison of torque T for motor control and allowable torque T ₀
If T> T ₀ , the deceleration torque T such that T = T ₀
Decelerates the servomotor. When the regenerative energy value is larger than the allowable regenerative energy value, the motor is decelerated by calculating a deceleration torque so that the regenerative energy value does not exceed the allowable regenerative energy value.
The regenerative resistor and the transistor are not burned by overheating. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of a servo motor regeneration processing circuit according to the present invention, and FIG. 2 is a flow chart of processing of a microcomputer (hereinafter referred to as a CPU) 4 of FIG. This servo motor regeneration processing circuit includes a comparator 1, a regeneration resistor 2, a CPU 4, a pulse counter 5, a pulse encoder 6, and a transistor 8. The comparator 1 is a servo motor (hereinafter simply referred to as a motor)
When a regenerative voltage generated when the motor 7 is decelerated is input, a regenerative current is output from the regenerative resistor 2 through the transistor 8.
Let it flow. In the regenerative resistor 2, regenerative electric energy is converted into heat energy and consumed. The pulse encoder 6 is connected to the shaft of the motor 7 and generates a pulse corresponding to the rotation of the shaft. The pulse counter 5 counts the pulses generated by the pulse encoder 6 and determines the number of rotations of the motor 7 by the CPU.
Tell 4 As shown in FIG. 2, the CPU 4 first determines in step 11 whether or not the operation of the motor 7 is a regenerative operation based on the following conditions. [0008] Ω: Motor rotation speed I: Motor armature current R: Motor armature resistance T _L : Load torque ω ₀ : Regeneration start motor rotation speed In the case of regenerative operation, the process proceeds to step 12, and the regenerative operation must be performed. To end. In step 12 calculates the allowable regenerative energy P _0. [0010] Here, C: capacity V _rg of the main capacitor 9: regenerative processing voltage V ₀ : allowable capacity of the main circuit DC voltage at normal time: allowable energy capacity of the regenerative resistor 2 and the transistor 8, and P ₀ > 0 If so, go to step 13. In step 13 calculates the allowable torque T _0. ## EQU3 ## Next, at step 14, the torque T for motor control is compared with the allowable torque T _0. If T ≦ T ₀ , the process is terminated. If T> T ₀ , the process proceeds to step 15. In step 15, to decelerate the motor 7 is stopped by decelerating torque T such that T = T _0. In this regenerative processing circuit, when the motor performs a regenerative operation, if the regenerative energy is greater than the allowable regenerative energy, the deceleration of the motor is suppressed by a deceleration torque such that the regenerative energy does not exceed the allowable regenerative energy. No current exceeding the allowable capacity 8 flows. The servo motor regenerative processing circuit of the present embodiment, the motor decelerates suddenly,
Even when decelerating under a negative load, the regenerative resistor and the like are not overheated and burned. As described above, according to the present invention, when the regenerative energy value is larger than the allowable regenerative energy value, the deceleration is suppressed so that the regenerative energy value does not exceed the allowable regenerative energy value. Even if the servo motor decelerates instantaneously or decelerates under a negative load, an excessive regenerative current does not flow through the regenerative resistor and the transistor, so that there is an effect that the resistor and the like are not burned out due to overheating.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of a servo motor regeneration processing circuit according to the present invention. FIG. 2 is a flowchart of processing of a CPU 4 of FIG. 1; FIG. 3 is a block diagram of a conventional example of a servo motor regeneration processing circuit. [Description of Signs] 1 Comparator 2 Regenerative resistor 3 Power transistor 4 CPU 5 Pulse counter 6 Pulse encoder 7 Servo motor 8 Transistor 9 Main capacitor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 3/18 101 H02P 7/63 H02P 6/02

Claims (1)

(57) [Claim 1] A transformer connected in parallel with a main capacitor.
Series circuit of transistor and regenerative resistor and servo motor rotation
Means for detecting the number of servomotors , wherein a regenerative current generated during operation of the servomotor is supplied to the regenerative resistor through the transistor to consume heat energy , and the operation of the servomotor is performed. The following formula determines whether or not the operation is regenerative.
Judgment is made according to the conditions shown in Here, ω: motor rotation speed I: motor armature current R: motor armature resistance T _L : load torque ω ₀ : regenerative start motor rotation speed In the case of regenerative operation, the allowable regenerative energy P _{0 is obtained} by the following equation.
Is calculated, and Here, C: capacity of the main capacitor V _rg : regenerative processing voltage V ₀ : allowable capacity of the main circuit DC voltage at normal time : allowable energy of the regenerative resistor and the transistor
If the capacity P ₀ > 0, calculate the allowable torque T ₀ according to the following equation.
Then, Comparison of torque T for motor control and allowable torque T ₀
If T> T ₀ , the deceleration torque T such that T = T ₀
A servo motor regenerative processing circuit for decelerating the servo motor.