JPS6331477A - Sinusoidal wave pwm signal generator - Google Patents

Abstract

PURPOSE:To arbitrarily set a voltage and a frequency with smaller ROM capacity by providing a plurality of waveform generating data tables on a RAM as a sinusoidal wave PWM signal generator. CONSTITUTION:In a sinusoidal wave PWM signal generator of an inverter using a 1-chip microcomputer, the microcomputer has a CPU 101, a timer 102, a RAM 103 for storing waveform generating data, a ROM 104 for storing waveform data tables, an address pointer 105, and a PWM signal output port 106. In this case, a plurality of waveform generating data tables are provided on the RAM 103, the waveform generating data written in the ROM by forming it by a personal computer is formed in the microcomputer, and written in the RAM 103. The PWM signal is generated on the basis of the data to eliminate the necessity of having a lot of data in the ROM 104, and the voltage and the frequency can be arbitrarily set.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inverter device, and particularly to a sine wave PWM signal generating device for an inverter to which a 1-deep microcomputer is applied.

[Conventional technology]

Figure 4 shows, for example, rAC servo motor and microcomputer control J
(February 1980) Published by General Electronic Publishing Company) “js
FIG. 6 is an internal block diagram of a microcomputer that generates a sine wave PWM signal using a microcomputer shown in Chapter 6. In the document No. F, a software timer is used for this purpose, but in this conventional example, an interval timer suitable for actual use is used. FIG. 5 is a flowchart of PWM generation interrupt processing, and FIG. 6 is a flowchart of main processing.

In FIG. 4, 101 is a CPU, 102 is a timer, 10
3 is a RAM that stores correction values; 104 is a ROM that stores a table of waveform generation data (port output data and hourly data) created by a calculator such as a personal computer; 1;
05 is a waveform data pointer, 106 is PWM (
This is a port that outputs the results.

Next, the operation will be explained using FIG. 4, FIG. 5, and FIG. 6.

As shown in flowchart 1 in FIG.
Increment the address pointer 105 of the table 501), and if the address pointer 105 is the table end, initialize the address pointer 105 502, 503), and transfer the data from the table to CPU10.
I and output the port output data to the port 106 (504). If the port output is zero' city pressure, the correction value stored in the RAM 103 is added to the time data (505, 506). Next, time data for the next interrupt is set in the timer 102 (507), and the interrupt processing is exited.

Thereafter, an interrupt occurs at the timing of the time data of the waveform generation data stored in the table in the ROM 104, and
The PWM signal is generated by repeating the operations from 01 to 507. Next, when changing the frequency, as shown in FIG. 6, it is determined whether the correction value is within the correction limit (602),
If it is within the limit, the correction value added in the RAM 103 in step 506 is changed. If the correction value exceeds the limit, RO
Change the table in M104.

(Problems to be Solved by the Invention) The conventional sine PWM signal generator is configured as described above, and as shown in FIG. Since the frequency is lowered and the voltage is lowered at the same time, the relationship between voltage and frequency cannot be set independently and has the disadvantage that it is determined uniquely.
And it is necessary to have many tables in ROM,
There was a problem in increasing the capacity.

The present invention has been made to solve the above-mentioned problems, and aims to provide a sine wave PWM signal generating device that can arbitrarily set the voltage and frequency with a small ROM capacity.

[Means for solving problems]

The sine wave PWM signal generator according to the present invention has a RAM-
A plurality of waveform generation data tables are created in H.

(Function) The sine wave PWM signal generating device according to the present invention creates waveform generation data, which was conventionally created in a personal computer and written in the ROM, in a microcomputer and writes it on the RAll.
A PWM signal is generated based on this data.

(Embodiments of the invention) Hereinafter, one embodiment of the present invention will be described in detail.

FIG. 1 is an internal block diagram of a microcomputer which is a computer showing one embodiment of the present invention. In the figure, 101 is a CPU;
! 02 is a timer, 103 is R for storing waveform generation data
AM, 104 is a ROM which stores a waveform data table such as reference sine wave data, 105 is an address pointer indicating a waveform generation data address in the waveform generation data table, and 106 is a port for outputting a PWM signal.

In FIG. 1, the part marked with a solid line shows the flow of interrupt processing for generating a PWM signal, and the part marked with a dotted line shows the flow of main processing for creating waveform generation data.

Next, the operation will be explained.

Flowcharts of the main IA process are shown in FIGS. 3a and 3b.

First, in the main process, it is determined in 301 whether there is a change in the frequency or voltage, and if there is a change, the process goes to the data creation program in 302. The data creation program selects the one that is not used in the interrupt processing as the output of the creation data (303).

Next, waveform generation data for 30° is created using the conventional triangular wave comparison method from the frequency data, voltage data, carrier frequency data, and waveform data stored in the ROM 104 (304).

At the same time, Jμ is opened from 30° data to 60° (
305), and further, in 306, time-short data (which cannot be processed by the microcomputer) is cut. When data creation is completed, a flag indicating that table switching is possible is set (307), and the main process is looped.

On the other hand, in the interrupt processing shown in the flowchart of FIG.
When interrupt processing is started by the timer 102, the address pointer 105 is incremented (201), it is determined whether or not it is the end of the table (202), and if it is the end of the table, a new table is switched. Next, the address pointer 105 is initialized.

Furthermore, the RAM 10 indicated by the atray pointer 105
3. Transfer the contents of the table above to the CPU.

206), sets the time data in the timer 102, and exits from the interrupt process. Thereafter, interrupt processing is performed at the desired timing to generate time data of the waveform generation data, and a PWM signal is generated.

According to one embodiment of the present invention, a plurality of waveform generation data tables are provided on the RAM, created on a personal computer, etc., and
Create the waveform generation data written in M in the microcontroller, write it on RAM, and perform PWM based on this data.
By generating a signal, ROM1. : There is no need for a lot of data, and since the waveform generation data is created from voltage and frequency data, there is no need to add zero voltage correction, and the voltage and frequency can be adjusted as shown in Figure 8. Ninmage: It has a vine effect when set to .

〔Effect of the invention〕

As described above, according to the present invention, it is not necessary to store a large amount of data in the ROM and J- in order to store the waveform generation data on the RAM, and furthermore, the waveform generation data can be created from voltage and frequency data. Therefore, there is an effect that there is no need to make corrections to the cello voltage, and a device that achieves ilf (:hi) can be obtained by arbitrarily setting the voltage and frequency.

[Brief explanation of drawings]

FIG. 1 is a microcomputer block 1, FIG. 2, FIG. 3a, and FIG. 3b are flowcharts showing an embodiment of the present invention, and FIG. 4 is a flowchart of a conventional microcomputer block 1, FIG. Internal block diagram, Figure 5. Figure 6 is a conventional flowchart, and Figure 7 is a conventional voltage/voltage chart.
Explanation of frequency patterns 1. J, FIG. 8 is an explanatory diagram of a voltage/frequency pattern according to an embodiment of the invention. In the figure, 101 is the CPU, 102 is the timer, and 103 is the RA.
M, 104 is ROM, 105 is address pointer, 10
6 is a port. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A computer-based sine wave PWM signal generator has a plurality of tables in RAM in which waveform generation data consisting of port output data and time data can be sequentially arranged,
It also has waveform data such as sine waves on the ROM, generates a PWM signal through timer interrupt processing using one table, and in parallel, uses the waveform data on the ROM and frequency and voltage commands through main processing. A sine wave PWM signal generator characterized in that waveform generation data is created in another table, and after the creation, the selected table is switched by interrupt processing and the frequency and voltage are sequentially changed.