JPH07108116B2 - Electric motor controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to a control device for an electric motor.

BACKGROUND ART Conventionally, in a control device for an inverter circuit that drives an induction motor using a microcomputer, the acceleration / deceleration time of the inverter circuit is a single set value during operation, so the acceleration / deceleration can be changed during the acceleration / deceleration. There wasn't.

[Object of the Invention] The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric motor control device capable of setting a desired acceleration / deceleration in a desired frequency range even during operation from an external control device. To provide.

DISCLOSURE OF THE INVENTION The present invention provides a switch unit for setting control condition data in a control circuit that controls an inverter circuit that drives an electric motor, and a display unit that displays the condition data set by the switch unit. And a terminal for fetching acceleration / deceleration setting data and a frequency setting signal for setting the rotation frequency of the electric motor from an external control device, respectively, in the electric motor control device including at least a RAM that stores the data of the set control conditions. When the arrival of the rotation frequency set by the frequency setting signal is detected, the terminal which controls and outputs the arrival signal to the external control device is provided in the control circuit, and the acceleration / deceleration setting data and the frequency setting signal from the external control device are provided. When inputting, adjust the motor rotation frequency so that the motor rotation frequency reaches the set frequency with acceleration / deceleration based on the acceleration / deceleration setting data. The inverter circuit is controlled by the control circuit, and the frequency control signal and the acceleration / deceleration control data output to the control circuit are switched in the external control device in response to the arrival signal.

The present invention will be described below with reference to examples.

FIG. 1 shows an embodiment of the present invention, in which an inverter circuit 1 controls switching of switching elements Q _{1 to} Q ₆ by an ON / OFF command from a control circuit 2 to control rotation of an induction motor IM. Is.

The control circuit 2 is controlled by a one-chip microcomputer (hereinafter abbreviated as CPU) 3 and receives an ON / OFF command signal U, V based on frequency setting data stored in advance in the built-in RAM 3a in response to a signal from the operation switch SW _4. , W is output. In addition, the control conditions are set by the signals of the switches SW _{1 to} SW _3, the setting conditions are displayed on the LED ₁ and LED ₂ of the display section, and the operation of writing them to the EEPROM 5 is performed. Also, when an error occurs, the error cause signal from the protection circuit 6 Distinguishes and displays LE
An error is displayed on D ₁ and LED ₂ , and the details of the error are EEPR
An abnormal signal ST for writing to OM5 and at the same time outputting an abnormal signal ST to the breaking relay 7 for breaking off the main contact S of the main circuit is output.

Next, the basic operation of the motor control device will be described with reference to the flowchart of FIG.

First, when the three-phase AC power supply AC of the device is turned on and the DC power supply Vcc is supplied from the power supply circuit (not shown) to the control circuit 2, the CPU3
Starts the operation by the built-in program, first the built-in RAM3a
The memory contents of is cleared once and initialization is attempted. After this initialization, the data such as the previous operating condition and the content of the final abnormality stored in the EEPROM 5 is read and written in the internal RAM 3a.

Next, the CPU 3 determines the mode, and determines the mode to be "00" because it is the initial state. At this time, the display LED ₁ is displayed as "00". When the mode is determined to be "00", "000" is drive-displayed on the display LED ₂ through a driver (not shown). Here, as the mode, the number of revolutions rises, descends,
There are each setting mode of V / F ratio of PWM control, braking time, maximum frequency, and abnormality cause reconfirmation mode, and it is possible to sequentially switch settings by operating the mode switch SW ₁ for mode setting.

In this initial display state (mode number "00"), the induction motor IM can be activated.

That is, if the setting conditions are not changed, the inverter circuit 1 can be controlled according to the previous setting conditions to drive the induction motor IM. When the mode switch SW ₁ is operated here, the CPU 3 advances to the mode in which “1” is added to the current mode number based on the operation of the mode switch SW ₁ , and reads the current setting data corresponding to this mode from the built-in RAM 3a. Display LED ₂ with a 3-digit number and display LED ₁ with the mode number. To change the setting condition currently displayed on the LED ₂ of the display unit, operate the data switch SW ₂ for data setting.In this case, the CPU 3 registers the data of the next setting condition in the same mode. and it is read out from the CPU3 of chip ROM, on display by the display unit LED ₂ and its contents.

If this display content is the desired setting condition, the user may operate the memory switch SW ₃ .

That is, the memory switch SW ₃ is a condition confirmation switch, and when the switch SW ₃ is turned on, the CPU 3 writes the data of the setting condition of the predetermined mode read for the above change in the built-in RAM 3a and the EEPROM 5. Rewrite the data of the relevant mode. When this rewriting is completed, the mode determination state is entered again.

By the way, if the setting condition displayed by operating the data switch SW ₂ is not the desired condition, the memory switch SW ₃
It is sufficient to repeatedly operate the data switch SW ₂ without operating, until the desired setting condition is satisfied.

Further, when it is desired to stop changing the condition, the mode switch SW ₁ may be operated without operating the memory switch SW ₃ to shift to the display of the next mode. In addition, when only confirming the setting conditions of the predetermined mode, it is good to repeat the operation of the setting switch SW ₁ , and in this case the modes are switched in sequence, and the display mode number of display LED ₁ and the display LED The data of the setting conditions of ₂ are switched and displayed sequentially. To reset the setting data to the initial state, turn on the reset switch SW ₅ .

Then, when the setting conditions of each mode are sequentially changed or confirmed and the initial mode number "00" is returned to, the state becomes ready for activation.

Now, when the operation switch SW ₄ is turned on to the start side in this mode "00", the CPU 3 senses the turning on and the on / off command signal U, based on the control condition written in the internal RAM 3a.
Outputs V and W. This command signal U, V, W is the inverter circuit 1
Switching elements Q _{1 to} Q ₆ via the base driver 4 of
To drive the three-phase induction motor IM.

Operating frequency of the drive-time display unit LED ₂ under the control of the CPU3
Displayed by.

By the way, when an abnormal state such as overload occurs in the induction motor IM and the rise in the voltage across the detection resistor R is detected by the protective circuit 6 due to this abnormal state, an abnormal detection signal is output from the protective circuit 6 and interrupts the CPU3. Give a signal. By this interrupt, the CPU 3 jumps the operation mode to the abnormal interrupt routine and shifts to the abnormal processing operation.

In other words, the CPU3 that has jumped to the abnormal interrupt routine stops the output of the on / off command signals U, V, W, stops the operation of the induction motor IM, and at the same time generates the abnormal signal ST. The contact S of the cutoff relay 7 inserted in is turned off to stop the power supply to the induction motor M. On the other hand, during this period, the CPU 3 of the control circuit 2 writes the abnormal data, which has been temporarily written in the internal RAM 3a from the protection circuit 6, to the abnormal data write address of the EEPROM 5, and based on the abnormal data, the display LED ₂
The error content is displayed on the display, and this display is reset
Hold until SW ₅ is operated.

Then, when the power supply to the control circuit 2 is also completely stopped, the operation of the entire device is completely stopped.

By the way, when the reset switch SW ₄ is turned on at the time of the above error display or the power is turned on again after the operation of the device is stopped, the CPU 3 is set to the initial state and the data of the control condition written in the EEPROM 5 and the data of the error content are written. Built-in RA
Transfer to M3a. When the system is restarted at the time of this transfer, if the above abnormality is not resolved, the protection circuit 6 detects the abnormality and the above-mentioned interrupt occurs, and the above-described abnormal interrupt routine is skipped.
When the switch SW ₁ is operated to set the error display mode, the details of the error that occurred during the previous operation are displayed on the display LED ₂ . The user can reconfirm the cause of the abnormality by displaying the LED _{2 on} the display section.

By the way, the control device of the present invention is provided with a terminal for connecting the external control device 8 such as a sequencer to the control circuit 2, and the external control device 8 comprises a frequency setting signal a by a voltage signal and 2-bit data. Acceleration / deceleration setting data b
When the rotation frequency of the electric motor IM controlled by the inverter circuit 1 reaches the set frequency, the control circuit 2 outputs the arrival signal c to the external control device 8.

When the external control device 8 is connected and the operation mode in which the external control device 8 is operated is set, the built-in RAM3
The frequency setting signal a from the external control device 8 is fetched instead of the data from a. 2 bits at the same time, that is, 4
Acceleration / deceleration setting data of a type is taken in, and the rotation frequency of the electric motor IM is accelerated / decelerated by determining the required time from the predetermined frequency to the set frequency based on the acceleration / deceleration setting data.
Figure 3 shows the control to gradually increase the rotational frequency by setting the acceleration period of the two-step f ₃ from f _2, f ₂ from f _1, f ₁ from zero to the desired rotational frequency f ₃ First, the external control device 8 outputs a frequency setting signal a ₁ corresponding to f ₁ as shown in FIG. 3 (a), and gives corresponding acceleration / deceleration setting data b to the control circuit 2. 2 increases the rotation frequency with a slope as shown in the x ₁ period of FIG. 3 (c), and when the frequency reaches f ₁ , FIG. 3 (b)
The arrival signal c ₁ shown in is output. The external control device 8 which takes in this arrival signal c ₁ responds to the frequency f ₂ with a frequency setting signal based on a program as shown in FIG. 3 (a).
_{When the} acceleration / deceleration setting data b is switched to ₂ at the same time, the control circuit 2 accelerates the rotation frequency from f ₁ to f ₂ based on these signals a ₂ and data b, as shown in FIG. 3 (c). The period is set to x ₂ and the rotation frequency is increased. When the frequency reaches f ₂ , the reaching signal c ₂ shown in FIG. 3 (b) is output. The external control device 8 which takes in this arrival signal c ₂ sets the frequency setting signal to the third value based on the program.
When switching to a ₃ corresponding to the frequency f _{3 as} shown in the figure (a) and switching the acceleration / deceleration setting data b at the same time, the control circuit 2 displays the signal a ₃ and the data b as shown in FIG. 3 (c). As shown, the rotation frequency is increased from x ₃ to f ₃ with the acceleration period for increasing the rotation frequency being x ₃ . When the rotation frequency rises to the frequency f ₃ and the reaching signal c ₃ is output from the control circuit 2, the external control device 8 does not find an abnormal frequency change, so the frequency setting signal is kept at a _3. Become. Therefore, the control circuit 2 maintains the rotation frequency at f ₃ .

[Advantages of the Invention] The present invention provides a motor control device configured as described above, wherein terminals for receiving acceleration / deceleration setting data and a frequency setting signal for setting a rotation frequency of the motor from an external control device, respectively, and the frequency setting signal. The control circuit is provided with a terminal for controlling and outputting an arrival signal to an external control device when it detects that the rotation frequency set in step 3 has been reached, and when the acceleration / deceleration setting data and frequency setting signal from the external control device are input, the motor The inverter circuit is controlled by the control circuit so that the rotation frequency of the electric motor reaches the set frequency at the acceleration / deceleration based on the acceleration / deceleration setting data, and the frequency setting is output to the control circuit in the external control device by the arrival signal. Since the signal and acceleration / deceleration setting data are switched, the acceleration / deceleration of the motor can be controlled from the external control device even during operation. It can be arbitrarily set in a desired frequency range, and has an effect that acceleration / deceleration can be freely performed according to the load of the electric motor.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of the above, and FIG. 3 is a time chart for explaining the operation of the same. 1 ... Inverter circuit, 2 ... Control circuit, 3 ... CPU, 3
a ...... Built-in RAM, 5 ... EEPROM, 8 ... External control device, a
…… Frequency setting signal, b …… Acceleration / deceleration setting data, c ……
Arrival signal, SW ₁ ~SW ₅ ...... switch, a LED _1, LED ₂ ...... display unit.

Claims (1)

[Claims] 1. A switch circuit for setting control condition data in a control circuit for controlling an inverter circuit for driving an electric motor, and a display section for displaying the data of the condition set by the switch device. In a control device for a motor having at least a RAM for storing data of control conditions, a terminal for fetching acceleration / deceleration setting data and a frequency setting signal for setting a rotation frequency of the motor from an external control device, and the frequency setting signal. The control circuit is provided with a terminal for controlling and outputting an arrival signal to an external control device when it detects that the rotation frequency set in step 3 has been reached, and when the acceleration / deceleration setting data and frequency setting signal from the external control device are input, the motor Inverter circuit so that the rotation frequency of the motor reaches the set frequency at the acceleration / deceleration based on the acceleration / deceleration setting data. The input control unit for an electric motor, characterized in that it has to switch the frequency setting signal and deceleration setting data to output to the control circuit in the external control device by the arrival signal to control the control circuit.