JPH09233829A - Inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the filter processing geared to the revolution of a motor by switching the filter processing for lessening the influence of noise by a frequency command, to the frequency command by the analog voltage inputted by a first setting means. SOLUTION: In the case of issuing the frequency command by an analog voltage input value, the influence on the frequency command by noise becomes larger when the output frequency is low than when it is high, therefore as the filter time constant for noise removal, the two kinds of a filter time constant for high speed and a filter time constant for low speed are prepared in an EEPROM 14 in advance, and the filter processing is performed, switching both filter time constants, according to the output frequency. Hereby, the filter processing geared to the revolution of a motor can be performed, so the removal of noise and the security of responsiveness of a high-speed region become possible.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device for controlling the speed of an electric motor, and more particularly to an inverter device for setting the rotation speed of the electric motor by an analog voltage signal.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram of a conventional inverter device. In the figure, 50 is an inverter device, 51 is a converter unit for converting an AC voltage into a DC voltage, 52 is a smoothing capacitor for smoothing the voltage converted by the converter unit 51, 53 is a bridge-connected transistor and a diode, An inverter unit that reconverts the DC voltage smoothed by the smoothing capacitor 52 into an AC voltage having a variable frequency, 54 is a control unit that creates a signal for driving the inverter unit 53, and 55 is an inverter unit that is created by the control unit 54. PWM signal for driving 53,
56 is a second for giving control parameters to the control means 54
Is an input interface, and 58 is an induction motor as an electric motor connected to the inverter device 50.

Next, the operation will be described. The converter 51 converts the three-phase AC voltage into a DC voltage, and the smoothing capacitor 52 smoothes the converted DC voltage. In the inverter unit 53, a DC voltage is converted into an AC voltage of a variable frequency according to the PWM signal 55 output by the control unit 54, and the induction motor 58 connected to the inverter device 50 is driven.

FIG. 9 is a block diagram showing the inside of the control means 54. In the figure, 59 is a microcomputer that calculates the output frequency, output voltage, and acceleration / deceleration time of the inverter device based on the frequency command, and 60 is a PWM for driving the inverter unit 53 based on the result calculated by the microcomputer 59. Signal 5
5, PWM signal generating means for generating and outputting 5, ROM 61 storing a program for calculation executed by the microcomputer 59,
Reference numeral 62 is a RAM as a work area used when the microcomputer 59 executes an operation, and 63 is a parameter setting means 5.
An EER that stores control parameters such as the frequency command conversion value for the analog voltage input value set by 6.
OM, 64 is an analog voltage input terminal as a first setting means, 65 is an A / D converter for converting an analog voltage input value input from the analog voltage input terminal into a digital value, and 66 is an external contact signal input means. is there.

Next, the operation will be described. Microcomputer 59
Receives the parameter set in the parameter setting means 56 via the input interface 57 and stores it in the EEROM 63. Further, the analog voltage input is received as a digital value via the A / D converter 65 and converted into a frequency command value based on the conversion value stored in the EEROM 63 in advance. Further, based on the frequency command, control calculation is performed according to the program stored in the ROM 61, and the calculation result is sent to the PWM signal generating means 60. The PWM creating means 60 creates a PWM signal based on the calculation result sent from the microcomputer 59 and outputs it to the inverter unit 53.

FIG. 10 is a diagram showing the relationship between the input voltage after the input voltage calibration and the output frequency. The relation of the output frequency with respect to the input voltage after the above-mentioned input voltage calibration becomes a linear function as shown in the figure, and if an arbitrary voltage is input here,
The output frequency is obtained according to the linear function.

A process of converting an analog voltage command into a frequency command in the above conventional inverter device will be described. Before operating the inverter device, for example, as shown in FIG. 10, frequency setting voltage bias and gain setting for converting a frequency command with respect to an analog voltage input value are performed in advance. (This operation is hereinafter referred to as input voltage calibration.) First, the frequency setting voltage bias is set. An arbitrary voltage bias is input from the analog voltage input terminal 64, and an output frequency corresponding to the voltage bias is input from the setting means 56. The CPU 59 receives the write signal from the parameter setting means 56, and stores the voltage bias value converted into a digital value through the A / D converter 65 and the output frequency corresponding to the voltage bias value in the EEPROM 62. By the same operation, the arbitrary voltage gain input from the analog voltage input terminal 64 and the output frequency corresponding to the gain value are also stored in the EEROM 62.

FIG. 11 is a flowchart for converting into a frequency command of a conventional inverter device. Next, a process of converting an analog voltage input value into a frequency command during operation of the conventional inverter device after input voltage calibration will be described. The voltage bias value converted into a digital value in step S51 is captured by the A / D converter 65. When the frequency command is given by the analog voltage input value, noise influences the frequency command. Therefore, in step S52, it is checked whether filter processing is necessary to reduce the influence of the noise. If filter processing is required, step S
At 53, filter processing is always performed according to the preset value set by the parameter setting means 56 regardless of the output frequency, and then the process proceeds to step S54. Step S
When the filter processing is not accepted in 52, the input voltage is converted into a frequency command according to a linear function after calibration in step S54.

Next, the frequency setting process of the conventional inverter device having a plurality of analog voltage input terminals will be described. In an inverter device having a plurality of analog input voltage terminals 64, the analog voltage input from each terminal is converted into a digital value by using the A / D converter 65, but the analog voltage input from each terminal Is
The same input voltage value is processed so as to have the same frequency command, and is converted into a frequency using one type of linear function determined by the above-mentioned input voltage calibration.

[0010]

The slight vibration of the input voltage is caused by
The influence is greater when the motor is rotating at low speed than when it is rotating at high speed. If the conventional filter processing is set in order to suppress the fluctuation of the rotation speed due to the vibration of the command voltage at the low rotation speed, the filter processing is performed up to the high rotation area where the slight vibration of the input voltage does not affect, and the entire rotation area However, there is a problem that the response to the frequency command becomes low.

Further, in the conventional device, the frequency resolution with respect to the input voltage can be arbitrarily set, but since the calibration operation cannot be performed while the inverter is operating, there is a problem in that it is impossible to change the frequency resolution during operation. It was

Further, even if a plurality of voltage input terminals are provided, there is a problem that the voltage calibration for one terminal is performed, so that it is not possible to correct each voltage input terminal.

The present invention has been made to solve the above problems, and a first object of the present invention is to provide an inverter device capable of performing a filtering process to reduce the influence of noise according to the rotation speed of a motor. I will get it.

A second object is to obtain an inverter device which can change the frequency resolution with respect to the input voltage even during operation to facilitate speed control of the induction motor by analog voltage input.

A third object of the present invention is to obtain an inverter device which has a plurality of voltage input terminals and can correct variations by the individual voltage input terminals.

[0016]

In an inverter device according to the present invention, a converter section for converting an AC voltage into a DC voltage, a smoothing capacitor for smoothing the DC voltage, and a smoothed DC voltage for converting the AC voltage. The inverter unit, the first setting means for setting the frequency command value by the analog voltage, the second setting means for setting the control parameter, and the frequency command by the analog voltage input from the first setting means. On the other hand, the control means switches the filter processing for reducing the influence of noise according to the frequency command.

Further, a second setting means capable of setting a reference frequency for switching the filter processing is provided.

Further, a second setting means capable of setting a plurality of filter time constants used for the filter processing is provided.

Further, the present invention further comprises a second setting means capable of setting a reference frequency for switching the filter processing and a plurality of filter time constants used for the filter processing.

Further, in the inverter device according to the present invention, a converter section for converting an AC voltage into a DC voltage, a smoothing capacitor for smoothing the DC voltage, and an inverter section for converting the smoothed DC voltage into an AC voltage. From the first setting means for setting the frequency command value with an analog voltage, the second setting means for setting the control parameter, the external contact signal input means for inputting the external contact signal, and the external contact signal input means. And a control means for switching the frequency resolution with respect to the set analog voltage according to the input external contact signal.

Further, a second setting means capable of setting a plurality of frequency resolutions is provided.

Further, in the inverter device according to the present invention, a converter section for converting an AC voltage into a DC voltage, a capacitor for smoothing the DC voltage, an inverter section for converting the smoothed DC voltage into an AC voltage, and a frequency First setting means for setting a command value with an analog voltage, second setting means for setting a parameter for control, and a frequency command for a plurality of analog voltage set values input from the first setting means. And a control means for individually converting.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment of the Invention FIG. 1 is a block diagram of an inverter device according to an embodiment of the present invention. In the figure,
51-53, 55-58 are the same as the conventional device, and the description thereof is omitted. Reference numeral 10 is an inverter device, and 11 is a control unit that creates a signal for driving the inverter unit 53.

FIG. 2 is a block diagram showing the inside of the control means of the inverter device according to the embodiment of the present invention.
In the figure, 55 to 57, 59, 60, and 64 to 66 are the same as those of the conventional device, and the description thereof will be omitted. Reference numeral 11 is a control means for generating a signal for driving the inverter unit 53, 12 is a ROM storing a program for calculation executed by the microcomputer 59, and 13 is a RAM as a work area used when executing calculation by the microcomputer 59. , 14 are EEROMs for storing control parameters set by the parameter setting means 56, such as frequency command conversion values for analog voltage input values.

FIG. 3 is a flowchart of the filter processing of the inverter device according to the embodiment of the present invention. When the frequency command is given by the analog voltage input value, noise affects the frequency command, but the effect of the noise on the frequency command is greater when the output frequency is lower than when it is high. As a time constant, a high-speed filter time constant is previously stored in the EEPROM 14,
Two types of low-speed filter time constants are prepared, and both filter time constants are switched according to the output frequency to perform the filtering process.

When the filtering process is started, step S
The current output frequency is read in 1 and it is determined in step S2 whether it is a high speed region or a low speed region. In the high speed region, the high speed filter time constant is read from the EEPROM 14 in step S3, and in the low speed region, EERO in step S4.
The low-speed filter time constant is read from M14. continue,
Filtering is performed in step S5.

The reference frequency for determining the high speed region or the low speed region in step S2, the high speed filter time constant read in step S3 and the low speed filter time constant read in step S4 are the write signal from the parameter setting means 56. In response, the CPU 59 uses the set value written in the EEPROM 14 and the RAM 13.

By the way, in the above-described embodiment, when the filtering process is started (corresponding to step S53 in FIG. 11),
In the flowchart shown in FIG. 3, an example of selectively using the high-speed filter time constant and the low-speed filter time constant has been shown.
It is also possible to determine whether or not the filtering process is executed by the determination in step S2 of FIG. For example, step S
When the reference frequency for determining the high speed region or the low speed region in 2 is 0 Hz, the high speed filter time constant is always selected. Therefore, the normal filtering operation is performed in the entire rotation range. If the high-speed filter time constant is set to 0, the operation matches the operation without filtering.

As described above, by setting the reference frequency for determining the high speed region or the low speed region in step S2, and setting the high speed filter time constant and the low speed filter time constant, the processing without the filter and the conventional filter are performed. It is possible to select each operation of the processing, the high speed filter processing and the low speed filter processing.

Embodiment 2 of the Invention FIG. 4 is a flowchart for switching the frequency resolution by the external terminal of the inverter device according to the embodiment of the present invention, and FIG. 5 is switching the frequency resolution by the external terminal of the inverter device according to the embodiment of the present invention. It is a figure which shows the relationship of the analog voltage and frequency command at the time. In FIG.
Reference numeral 21 is a straight line of the frequency command for the analog voltage in the normal mode, and 22 is a straight line of the frequency command for the analog voltage in the simple positioning mode.

The process of changing the frequency resolution according to the external contact signal will be described with reference to FIGS. In step S11, the ON / OFF state of the external contact signal 66 is read out, and in step S12, it is checked whether the simple positioning mode is designated. If the simple positioning mode is not designated, the gain frequency according to the straight line 21 of the normal mode of FIG. 5 is selected in step S13, and if the simple positioning mode is designated, the step S13 is performed.
At 14, the gain frequency according to the straight line 22 in the simple positioning mode of FIG. 5 is selected. Here, the value of the frequency voltage gain in the normal mode in step S13 and the value of the frequency voltage gain in the simple positioning mode in step S14 are set by the CPU 59 in the EEPROM 12 and the RAM 13 in response to the write signal from the parameter setting means 56. Use value. Then, the frequency command is changed in step S15.

Since the calculation method of the frequency command for the analog voltage can be changed depending on the ON / OFF state of the external contact signal 66, the analog voltage input for the normal frequency command and for the analog voltage input in the simple positioning mode can be changed. The frequency resolution can be easily switched.

Next, the operation method will be described. In the case of normal speed control, the analog voltage command is converted to the frequency command in the normal mode in the same manner as the conventional method. When the operator of the inverter tries to perform the simple positioning control and specifies the simple positioning mode by the external setting signal, the frequency command is switched from f1 to f2 even with the same analog voltage input VIN as shown in FIG. Can be decelerated to f2, the frequency resolution is improved after deceleration is started, and precise speed control can be performed. Therefore, simple positioning control by analog voltage input is facilitated.

Embodiment 3 of the Invention FIG. 6 is a flowchart for calculating a frequency command from an analog voltage input value of the inverter device according to the embodiment of the present invention, and FIG. 7 is a flowchart of a plurality of inverter devices according to the embodiment of the present invention. FIG. 3 is a diagram showing a relationship between an input voltage and an output frequency when input voltage calibration is performed for each analog voltage input terminal. In the third embodiment of the invention, in an inverter device having a plurality of analog voltage input means, the frequency resolution for each analog voltage input value is individually set.

In FIG. 2, the CPU 59 receives the write signal from the parameter setting means 56 and sets the frequency setting voltage bias Va set at the analog voltage input terminal 64.
1 and the output frequency for the voltage bias set in the setting means 56 are stored in the EEPROM 14. Further, by the same operation, the arbitrary frequency setting voltage gain set in the analog voltage input terminal 64 and the output frequency corresponding to the gain value are stored in the EEPROM 14. Next, the frequency setting voltage bias Va2 and the frequency for the bias value, and the frequency setting voltage gain and the frequency for the gain value are also stored in the EEPROM 14 by the same method.

As described above, there are two types of linear functions of the frequency command for the voltage input, that is, the frequency setting voltage bias Va1 and the frequency setting voltage bias Va2.

Next, the processing from the analog voltage input to the calculation of the frequency command will be described with reference to FIGS. 6 and 7. The analog voltage input Va1 acquired in step S21 is
A / D conversion is performed in step S22, and the frequency command f1 is calculated from the A / D converted value in step S23. In step S24, the value of f1 is stored. Then, the analog voltage input Va2 fetched in step S25 is A / D converted in step S26, and the frequency command f2 is calculated from the A / D converted value in step S27. In step S28, the value of f2 is stored. Step S29
In step S24, f1 stored in step S24 and step S2
The frequency command is synthesized with f2 stored in 8.

Next, a method of operating the frequency command will be described. For example, if there are two analog voltage input terminals,
As shown in FIG. 7, one is a normal frequency command terminal,
One is assigned as a high-accuracy frequency command terminal.If the accuracy is the same as the conventional one, the command is sent using the frequency setting voltage bias from the normal frequency command terminal.If you want to increase the frequency command resolution, use the normal frequency command. Terminals and high-precision frequency command terminals are used together, first a rough command is sent by the frequency setting voltage bias from the normal frequency command terminal, and then the frequency command is finely adjusted using the frequency setting voltage bias from the high-precision frequency command terminal. To do.

As described above, the input voltage calibration is performed for each terminal, and the frequency command for each voltage command is obtained according to the calibration value, whereby the frequency resolution of each terminal can be set individually.

[0040]

Since the present invention is constructed as described above, it has the following effects.

Since the filter processing can be performed according to the number of rotations of the motor, the influence of noise in the low speed region can be removed and the responsiveness in the high speed region can be secured.

Since the low speed region and the high speed region can be arbitrarily set, it is possible to switch and execute the filter processing according to the application.

Further, since the filter time constants in the low speed region and the high speed region can be arbitrarily set, the degree of correction by the filter process can be selected according to the application.

Furthermore, the low speed region and the high speed region can be arbitrarily set, and the low speed region,
Since the filter time constant in the filter processing for each of the high speed regions can be arbitrarily set, it is possible to appropriately select a plurality of filter processings according to the application.

Since the resolution of the frequency command by the analog voltage can be switched by the external contact signal, the normal frequency command can be operated without stopping the inverter even during the operation of the inverter, and the precise frequency command can be changed. It is possible to switch to the required driving.

Further, since the frequency resolution can be arbitrarily set, it is possible to set an appropriate frequency according to the operating condition when switching, such as the positioning accuracy or the target speed.

Further, since the input voltage is calibrated for each voltage input terminal and the frequency command is obtained from the calibrated value, the resolution of the frequency command can be set individually and the variation of each voltage input terminal can be corrected. Becomes Further, since the resolution of the frequency command of each voltage input terminal can be arbitrarily set, the frequency command can be finely adjusted.

[Brief description of drawings]

FIG. 1 is a block diagram of an inverter device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the inside of a control unit 20 of the inverter device according to the embodiment of the present invention.

FIG. 3 is a flowchart of a filter process of the inverter device according to the embodiment of the present invention.

FIG. 4 is a flowchart for switching frequency resolution by an external terminal of the inverter device according to the embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between an analog voltage and a frequency command when the frequency resolution is switched by the external terminal of the inverter device according to the embodiment of the present invention.

FIG. 6 is a flowchart for calculating a frequency command from an analog voltage input of the inverter device according to the embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between an input voltage and an output frequency after performing voltage input calibration for each of a plurality of analog voltage input terminals of the inverter device according to the embodiment of the present invention.

FIG. 8 is a block diagram of a conventional inverter device.

FIG. 9 is a block diagram showing the inside of the control unit 4.

FIG. 10 is a diagram showing a relationship of an output frequency with respect to an input voltage after voltage input calibration.

FIG. 11 is a flowchart of conversion into a frequency command of a conventional inverter device.

[Explanation of symbols]

10 inverter device, 11 control means, 12 R
OM, 13 RAM, 14 EEROM, 21
Straight line of frequency command for analog voltage in normal mode, 22 Straight line of frequency command for analog voltage in simple positioning mode, 50 inverter device, 51 converter section, 52 smoothing capacitor,
53 inverter part, 54 control means, 55 PW
M signal, 56 parameter setting means, 57 input interface, 58 induction motor, 59 microcomputer,
60 PWM signal creating means, 61 ROM, 6
2RAM, 63 EEROM, 64 analog voltage input terminal, 65 A / D converter, 66 external contact signal input means.

Claims (7)

[Claims] 1. A converter unit for converting an AC voltage into a DC voltage, a smoothing capacitor for smoothing the DC voltage, an inverter unit for converting the smoothed DC voltage into an AC voltage, and a frequency command value set by an analog voltage. First setting means and second setting means for setting control parameters;
An inverter device comprising: a frequency command based on the analog voltage input from the first setting unit; and a control unit that switches filter processing for reducing the influence of noise according to the frequency command. 2. The inverter device according to claim 1, wherein a reference frequency for switching filter processing can be set by the second setting means. 3. The inverter device according to claim 1, wherein a plurality of filter time constants used for the filtering process can be set by the second setting means. 4. The inverter device according to claim 1, wherein the second setting unit can set a reference frequency for switching the filter processing and a plurality of filter time constants used for the filter processing. 5. A converter section for converting an AC voltage into a DC voltage, a smoothing capacitor for smoothing the DC voltage, an inverter section for converting the smoothed DC voltage into an AC voltage, and a frequency command value set by an analog voltage. First setting means and second setting means for setting control parameters;
An inverter device comprising: external contact signal input means for inputting an external contact signal; and control means for switching the frequency resolution for the set analog voltage according to the external contact signal input from the external contact signal input means. 6. The inverter device according to claim 5, wherein a plurality of frequency resolutions can be set by the second setting means. 7. A converter section for converting an AC voltage into a DC voltage, a smoothing capacitor for smoothing the DC voltage, an inverter section for converting the smoothed DC voltage into an AC voltage, and a frequency command value set by an analog voltage. First setting means and second setting means for setting control parameters;
An inverter device, comprising: a control unit that individually converts a frequency command with respect to a plurality of analog voltage set values input from the first setting unit. [0001]