JPS63117667A - Control circuit for inverter - Google Patents

Abstract

PURPOSE:To control an inverter at a high speed by storing in advance a timing command of selecting or converting data in a memory provided separately from a program control, thereby shortening a program. CONSTITUTION:The waveform control circuit of a constant frequency sinusoidal wave inverter is composed of a time base 1, a counter 2, a microprocessor 3, an A/D converter 4, a multiplexer 5, a sample-holder 6, etc. In this case, a memory 10 composed of an ROM is provided, and an output addressed by the counter 2 is applied as a timing command of converting and selecting through a latch 11 to the converter 4, the multiplexer 5 and the holder 6. Thus, the memory 10 of the inverter can write an alteration command of data in coincidence with a timing command required for data in calculation, and also rewrite in coincidence with the alteration of a program.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control circuit for an inverter device that controls the timing of selection and conversion of calculation data in a control circuit for a constant frequency sine wave inverter.

[Conventional technology]

For example, Figure 3 is from the Institute of Electrical Engineers of Japan Semiconductor Power Conversion Study Group material dated July 12, 1986 (material number, spc-86-).
59) is an example of a waveform control circuit for a constant frequency sine wave inverter. In the figure, 1 is a time base such as a crystal oscillator, 2 is a counter, and 3 is a program in synchronization with the time base 1 and counter 2. A controlling microprocessor 4 is an A/D converter and uses the output signal of the multiplexer 5 as an analog signal input. 6 is the same circuit as 3
A/D converter 4, which includes the microprocessor 3, is a sample holder equipped with circuits. The sample holder 5° multiplexer 6 is collectively referred to as a conversion device.

7 is the inverter output voltage (voltage applied to the load) V
C%8 is the inverter current, and 9 is the load current IL.

Next, the operation shown in FIG. 3 will be explained with reference to the time chart shown in FIG. First, the microprocessor 3 that performs program control determines the time at which data necessary for calculation is stored using the inverter current generator and output voltage vc.

It is assumed that the load currents IL are 'rt' and T21T3, respectively. Then, a hold command is output to the three sample holders 6 at the program start time To, and at the same time, the multiplexer 5 selects the inverter current output. Next, when the output of the multiplexer 5 becomes stable, a conversion command is output to the A/D converter 4, and after the required conversion time, the A/D
The D converter 4 outputs the digitally converted inverter current value and the microprocessor 3 takes in this at time T1, at the same time the multiplexer 5 selects the output voltage Vc. Thereafter, in the same manner, the digitally converted output voltage VL is taken in at time T2, and the digitally converted load current IL is taken in to the microprocessor 3 at time T3.

((CL) is a data selection and conversion program) *
Please note that when you come to the United States, you will receive the data necessary for each of the above calculations for one person, Vc, and IL.
are the A/I) converted data of engineering λ, Vc, and IL, respectively.

The timing of all the above operations is determined by the program of the microprocessor 3 in the A/D converter 4. Multiplexer 5. This is done by giving commands to the sample holder 6. (CA) is the control calculation program after data selection and change *CL).

[Problem that the invention seeks to solve]

Since the control circuit of the conventional inverter device is configured as described above, the microprocessor is occupied with data selection and conversion at least during the period from start time To to time T3. Therefore, in the control of this type of inverter device that requires high-speed control, the time for one cycle from the start time TD to the cycle end time Tst must be around 100 μs, and setting such a cycle time will adversely affect the control calculation. There were problems such as insufficient processing time.

This invention was made to solve the above-mentioned problems, and it is possible to select and convert data without commands from the microprocessor, and to adjust the timing of data acquisition to the optimum timing required by the microprocessor. [Means for solving the problem] The control circuit for an inverter device according to the present invention is capable of controlling timing commands for data selection and conversion by program control in advance. is stored in a separate memory, and accessed by the output of a counter according to the time base, the timing command for selection and conversion is extracted and given to the sample holder, data selector, and A/D converter. It is something. Further, the memory has a plurality of patterns, and a desired pattern can be arbitrarily selected.

[For production]

In the memory of the inverter device according to the present invention, data conversion commands can be written in accordance with timing commands that require data for calculations according to the program of the microprocessor, and it can also be rewritten in accordance with changes in the program.

〔Example〕 .

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same parts as in FIG. 3 are indicated by the same reference numerals. In FIG. 4. Multiplexer 5. It is given to the sample holder 6 as a timing command for conversion and selection.

Next, the operation will be explained with reference to the flowchart shown in FIG. First, the time base pulse value counted by the counter 2 according to the time base 1 is sequentially designated as an address to access the memory 10. Then, as a pattern for each bit in the memory 10, an acquisition command to the sample holder 6, a selection command to the multiplexer 5, and a conversion command to the A/D converter 4 are output, and data acquisition (CL) is performed. The latch 11 is a circuit inserted to remove a hazard from the output of the memory 10, and is not particularly necessary for the sake of illustration, so it will be omitted. Also, data acquisition by the microprocessor 3 is performed at the time Top Ttt e Txz #
The microprocessor 3 only needs to take in the data without outputting data selection or conversion commands. Therefore, time T1t # Tt
It becomes possible to execute control calculations (CA) before and after ze Tts.

Incidentally, in the above embodiment, an example was explained in which ROM was used as the memory, but RAM -? It is also possible to store a plurality of patterns in the memory and to operate the inverter while selecting an appropriate pattern according to changes in the operating mode of the inverter. Chiru.

〔Effect of the invention〕

As described above, according to the present invention, data acquisition and control calculations are performed by issuing timing commands from hardware without relying on microprocessor software for data selection and conversion timing commands. ,
This has the effect of enabling high-speed control of the inverter device, which allows the program to be shortened. Furthermore, since memory is used as the hardware, it is possible to easily change the timing of commands.

[Brief explanation of the drawing]

FIG. 1 is a control circuit block diagram of an inverter device according to an embodiment of the present invention, FIG. 2 is a time chart explaining the operation of FIG. 1, FIG. 3 is a control circuit block diagram of a conventional inverter device, and FIG. The figure is a time chart explaining the operation of FIG. 3. In the figure, 1 is a time base, 2 is a counter, 3 is a microprocessor, and 10 is a memory.

Claims (3)

[Claims] (1) In a control circuit for an inverter device that controls a microprocessor by synchronously operating a counter using a time base and periodically controls the microprocessor by feeding back the output data of the inverter device to the converter device, the inverter output to the converter device is controlled. A control circuit for an inverter device, characterized in that timing commands for data selection and conversion are determined by a memory provided separately from the program control of the microprocessor. (2) The control circuit for an inverter device according to claim 1, wherein the memory is configured with a ROM. (3) The control circuit for an inverter device according to claim 1, wherein the memory includes a plurality of timing command patterns, and a desired pattern can be selected.