JPH03112367A - Inverter controller - Google Patents

Abstract

PURPOSE:To improve resolution of operational frequency by storing a predetermined number of step data into a temporary memory means and outputting a PWM waveform, corresponding to the step data, from a real timer I/O port. CONSTITUTION:A memory section 12 is provided with a basic wave data based on a predetermined sine wave 11, a time data based on the basic wave data and a carrier wave 13 having a predetermined frequency, and a step data for reading out the basic wave data in order to combine the time data according to the operational frequency. A plurality of step data are provided for every frequency and a predetermined number of step data are read out according to the operational frequency. The step data are changed in step and the step data having modified frequency is finally stored in an inner memory RAM 10a. By such arrangement, resolution of the operational frequency can be improved and the frequency can be varied smoothly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inverter control device used to control a load (for example, a compressor of an air conditioner, etc.), and more specifically, it relates to an inverter control device that increases the resolution of an inverter frequency, This invention relates to an inverter control device that changes operating frequency extremely finely.

[Conventional example] In recent years, this type of inverter control device has come to be used not only in air conditioners but also in various home appliances.

Here, to explain an air conditioner as an example, as shown in FIG. part 2, a memory part 3 that stores various waveform data corresponding to the operating frequency of the compressor 1, such as time data and switch data for 60 electrical degrees (or 30 degrees), and a memory part 3 that stores various waveform data corresponding to the operating frequency of the compressor 1, and A control unit (CPU
A microcomputer 4 is provided, and a base drive unit 5 that drives a plurality of transistors according to control signals thereof.

Then, when a command for a predetermined operating frequency is output in accordance with the operation of a remote control, panel, etc., waveform data for 60 electrical degrees corresponding to the operating frequency command is read out from the memory section 3, and these waveform data are PWM of compressor 1 based on
Waveform ((plus width modulaiti
on; pulse signal) is obtained. At this time, as shown in FIG. 12, if the time data storage control method is used, the waveform data is sine waves 6, 7 of U phase, ■ phase, and V phase.
．． 8 and the carrier waveform 9 to the next intersection (time data), and data on the magnitude of the carrier waveform 9 and the sine wave 6 during that time (switch data). In this case, as shown in FIG. 13, for example, in section A, time data of 50 μs and 1
/O0111.0" switch data is obtained, and in section B, 64 μs time data and "/O/O/
The switch data "X+Y+Z" is "U, V".

Therefore, time data and switch data "u, v, w" corresponding to the operating frequency of the compressor 1 are stored in the memory section 3 in advance. The switch data is repeatedly read from the memory, and a basic waveform pattern (PlNM waveform) of 60 degrees based on the waveform data is repeated to obtain a one-cycle pattern (approximate sine wave).

To explain in more detail, the power and
Turn on each transistor in transistor section 2.

A signal to turn off is output for a predetermined period of time by the control unit 4, but
First, the I/O boat (υl v, Wt
x.

y, z), a signal of "0011/O" is output for a period of 50 μs. Furthermore, next is the I/O port (L L
From L Xy V+2), “/O/O
/O" signal is output. Similarly, the I/O boat (U, V, enemy Ru. That is, the I/O boat outputs a pulse train of these “1nuO” signals, and these pulse trains are input to the base drive unit 5. Then, each transistor of the power transistor section 2 is driven by the base drive section 5, and the output (U, V
, 11) is applied to the compressor 1. Due to these pulsed voltages, uv, vw, and wu interphase voltage waveforms are applied to the compressor 1, so an approximate sinusoidal current flows through the compressor 1, and the compressor 1 The motor is driven.

[Problems to be Solved by the Invention] However, in the above inverter control device, the voltage/operating frequency (V/F) of the load is controlled at a constant level, so the data for obtaining the above PWM waveform is If you try to increase the resolution of the inverter frequency and make extremely fine changes in the operating frequency, the amount of data becomes enormous and the memory capacity becomes large.

This invention was made in view of the above problems, and its purpose is to provide an inverter control device that can increase the resolution of the inverter frequency without increasing the memory capacity, and can change the operating frequency extremely finely. Our goal is to provide the following.

[Means for Solving the Problems] In order to achieve the above object, the present invention reads waveform data corresponding to the target frequency of the load from a memory when controlling the load with an inverter, and also reads out waveform data corresponding to the target frequency of the load and performs control based on this waveform data. In an inverter control device that obtains a PIl1M waveform, drives a switching transistor ON/OFF using this PIIIM waveform, and outputs a voltage waveform to be applied to the load, an electrical angle of 60 degrees, 120 degrees, or 180 degrees of a predetermined sine wave is used. A first memory that equally divides the sine wave and stores the height value of the sine wave at this equally divided position as fundamental wave data, and stores step data that reads out the fundamental wave data corresponding to the operating frequency of the load. a second memory for storing voltage data for adjusting the voltage of the output waveform by multiplying it by the fundamental wave data described in 1. , a fourth memory that stores the interval from the peak or trough of the carrier wave to the position of the carrier wave corresponding to the fundamental wave data as time data; temporary storage means for storing the number of step data; 1. When changing the operating frequency, read the step data from the second memory in units of the fixed number; reads the step data and stores it in the temporary storage means, reads the fundamental wave data based on the stored step data, multiplies the fundamental wave data by the voltage data, and corresponds to the calculated value. control means for setting the time data to an internal real timer every half period of the carrier wave, and inverting and controlling the output of the real timer I/O port according to the set value of the internal real timer. The gist is that the above-mentioned PIIM waveform is obtained.

8 [Function] With the above configuration, when controlling a load (for example, a compressor) with an inverter, the temporary storage means (internal memory RA
A fixed number (for example, 20) of step data stored in M) are sequentially read out. Fundamental wave data is read based on the step data, and the fundamental wave data is multiplied by voltage data corresponding to the operating frequency of the compressor. Further, the time data corresponding to the calculated value as a result of the multiplication is read from the fourth memory and set in the real timer, and the set of the real timer is the timer time of the PυM timer (half cycle of the carrier wave). It is done every. Namely.

Since the output of the real timer I/O boat is inverted controlled when time data has elapsed from the start of the PldM timer, the operating frequency of the compressor can be determined from the real timer I/O boat based on the above fixed number of step data. A PIIM waveform corresponding to is output.

Here, when the operating frequency is changed, the contents of the temporary storage means are rewritten. This rewriting is performed by shifting one step data at a time in units of the above-mentioned fixed number, and a fixed number of step data is always stored in the above-mentioned fixed storage means. When a fixed number of step data corresponding to the changed frequency is stored in the temporary storage means, rewriting of the fixed storage means is stopped. In this way, since a certain number of step data are stored in the temporary storage means, a PWM waveform corresponding to the step data is output from the real timer I/O port as described above. Therefore, there is no need to increase various data to obtain the PWN waveform, so the memory capacity can be reduced, and the resolution of the operating frequency (1) is increased, making it possible to smoothly change the frequency. .

[Embodiments] Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 0. In FIG. 1, the same parts as in FIG. 11 are designated by the same reference numerals, and redundant explanation will be omitted.

In FIGS. 1 to 8, the inverter control device includes:
Control unit with real timer and its I/O port (
CPU (microcomputer)/O is provided, and further the predetermined sine wave 11 is divided into 60 degrees, 120 degrees, or 180 degrees of electrical angle (for example, the 60 degrees of electrical angle of the sine wave is divided into 255 equal parts), A first memory 12a stores the height values of the sine wave 11 obtained at the equally divided positions as fundamental wave data (shown in FIG. 3), and reads out the fundamental wave data according to the operating frequency of the load. Second memory 12b for storing step data (shown in FIG. 4)
and a third memory 12c that stores voltage data (shown in FIG. 5) to be multiplied by the fundamental wave data read out by the step data, and a carrier wave 13 of a constant frequency is superimposed on the sine wave 11, The interval from the peak or valley point of this carrier wave 13 to the position of the height value of the sine wave 11 obtained by the above-mentioned equal division is determined as time data 1. A memory section 12 having a fourth memory 12d for storing data as II (shown in FIG. 8) is provided. In addition, the control unit/O is
When controlling the load inverter, an internal memory RAM (RAM) that stores a certain number of step data in the second memory 12b is used.
Temporary storage means)/Oa and this internal memory RAM/Oa
The step data of are sequentially read out, the fundamental wave data is read out based on this step data, the fundamental wave data is multiplied by the voltage data, and the time data corresponding to this calculated value is stored for a certain period of time, e.g. Half cycle time of the above carrier wave (PWM timer time)
It has a function to set the above real timer for each time.

Note that in FIGS. 2 and 3, the fundamental wave data is an average value in equal division, but it may be a value at one end of the equal division.

In addition, the fundamental wave data is such that the peak value H of the sine wave 11 is 25
5, the carrier frequency fc is 3.3 kl (z), and the control rate is 2.

Here, with reference to FIGS. 2 to 8, the first to fourth memories 12a, 12b, L2c, 12
The data stored in d will be explained.

First, as shown in Figure 2, the wave height value (H = 256)
60 degrees of sine wave 11 is divided into 255 equal parts, and the height (Ha) of sine wave II in this equal division is Ha = 255s
inθ, and this calculated value is combined with the fundamental wave data. Also, in the same manner as above, 60 degrees to 12 degrees of the sine wave 11
25 degrees each at 0 degrees and 120 degrees to 180 degrees.
The height of the sine wave 11 in this equal division is calculated, and this calculated value is used as the fundamental wave data (shown in FIG. 5).

Further, as shown in FIG. 4, the step data becomes larger as the operating frequency of the load becomes higher. When the compressor 1 is controlled at that operating frequency, a certain number (
The reference wave data is sequentially read out using step data (for example, 20 pieces).

Furthermore, as shown in FIG. 5, the voltage data has the function of adjusting the voltage of the output waveform, and is multiplied by the fundamental wave data read above to obtain time data I, I, which will be described later.
A calculated value for obtaining f is calculated.

Furthermore, as shown in FIGS. 6 to 8, the interval (time 1Tai) from the peak of the carrier wave 13a with a negative slope to the intersection αa between the carrier wave 2 and the fundamental wave data is time data I. , positive slope IZ- The interval (time; T bi) from the trough of the carrier wave 13b to the intersection αb between the carrier wave 2 and the fundamental wave data is time data ■. Note that the second memory 12d
The calculated value i is stored in correspondence with the time data I and II (as shown in FIG. 6).

Next, the operation of the inverter control device will be explained based on the flowchart and time chart of FIG.

First, assuming that the operating frequency command for the compressor 1 is, for example, 167, F16 is set for the symbol (F) (step 5TI). At this time, PvM in the control unit/O
Since the predetermined time of the timer is set to half the period of the carrier wave, the PIIM timer is set to the period (for example, 150
It operates repeatedly in microseconds (μs). Then.

It is determined whether the timer time of the PWM timer has elapsed, that is, it is the rising or falling timing of the P-timer, and if the timer time has not elapsed, it is determined whether or not the above-mentioned operating frequency is to be changed. A determination is made (step 5T2). If there is no change in the operating frequency, the real timer is set based on the step data (fixed number; 20 pieces) stored in the internal memory RAM10a, and the real timer 1/O port 1- is set by this real timer. Controlled in reverse. With this reversal control, the real timer 1/O-to switches the compressor 1 to the above 16
A PV waveform controlled in Hz is obtained.

Then, when the operating frequency is changed, for example, from 167 to 17 (step 5T2
), a timer (for example, a 0.1 sec timer) is set (step 5T3). Furthermore, the new station wave number (1
7Hz) symbol "17" is set (step 5T4), and a changing flag (H
F') is set to 1 (step 5T5). Subsequently, it is determined whether the change is an increase or decrease in frequency (step 5T6). In this case, since the 1 frequency has been changed from 16Hz to 171 (Z), the process proceeds to step ST7, and the start address (SA) for reading the step data of the setting symbol F17 is calculated (step 5T7). Then, the previous symbol At F16, the start address (SA) is set to II (5++, so the start address (SA) is 5+1
=6 is set, and 1125 N is calculated from address "6" to obtain 20 pieces of step data, for example.

Subsequently, those addresses gt 6 tr to II 25
++ step data 11311 113” +13
Internal memory RA by 1+, 1+ 31+,...
Ml0a is rewritten (step 5T8).

Subsequently, when the timer I times up (step 5T9), it is determined whether the start address is the address of a new symbol (F17) (step 5TIO).
). At this time, since the first address is rr 6 u, the process returns to step ST6 and the step ST7
Sr1 is repeated from ``
9". That is, when changing the operating frequency, the internal memory RAM 10a finally contains the step data "3" from address II 97+ of symbol F17 to 28" lr 3 II II 4
I+"4", .
l0a is shifted by one address, and the number of units is 1.
5- The step data is rewritten. Then, the start address (SA) is the address LL of the new symbol F17 9
When it reaches ++, the changing flag (HF) changes to rr O.
rr (the flag is lowered) (step 5T
II), the process returns to step ST2 and the above steps are repeated.

Here, in step ST8, a fixed number of step data is stored in the internal memo January IAM/Oa, and the fundamental wave data is sequentially read out using this fixed number of step data. That is, as shown in FIG. 3, those step data are tt 31F "
3", "3"..., Nα is +12 IT due to (magic) + (step data), 115 II
, II 8 JT..., and the fundamental wave data of these addresses it 3 II "6" it 9 +
+... (in the case of 60 electrical degrees) is read out. Furthermore, these fundamental wave data and voltage data are sequentially multiplied, but when the maximum control rate of the compressor 1 is 2, 0.0
In order to obtain a control rate with an accuracy of 1 /O0 times, that is, the voltage data is "200", the calculation of fundamental wave data x (voltage data / 200) is performed sequentially, and the predetermined calculated value shown in Fig. 8 is obtained. can get. Then, time data corresponding to the calculated value is obtained. For example, if the previous time data is time data I, time data ■ corresponding to the same calculated value is read out from the first memory 12d, and those time data is obtained corresponding to 20 step data.

On the other hand, when the operating frequency is changed from 161 (z to 157), the process proceeds from step 6 to 5TL2, and the start address (SA) is sequentially subtracted by 5A=SA-1. In other words, the above-mentioned increase in the operating frequency In the case of
a is rewritten (step 5T8).

Further, as described above, time data is obtained from the step data stored in this internal memory RAM10a.

Since the time data I and II are obtained in sequence and set in the real timer as described above, a PWM waveform for controlling the compressor 1 is output from the real timer 11 port. In addition, if the 1M waveform is the U phase, the internal memory RAM/O
Time data I and II corresponding to the V phase and W phase can be obtained from the fundamental wave data and voltage data read out using the step data stored in a. and,
The time data is sent to the real timer.
Therefore, from real timer I/O baud 1-, υ phase,
PW waveforms of V-phase and R-phase are output. By setting the tie 11 data, inversion control of the real-time 1/O port 1- is performed, and when the timer time of the PIIM timer elapses, the timer is reset and started, and the next time data is set. Furthermore, in the same way as above, processing to obtain the next time data I or 1 is performed using the next step data stored in the internal memory liAM/Oa, and the above real timer is set to change the timer time and carrier frequency. Executed every half cycle. Then,
As shown in Figure /O, real time 11 port 1-
is subjected to inversion control after the time data from the timing of the half cycle, and by this inversion control, a PldM waveform for controlling the compressor 1 at 17 Hz is obtained19-.

In addition, the real-time 11 ports output U-phase, V-phase, and V-phase PWM waveforms, as well as their inverted X-phase, y-phase, and 2-phase PIjM waveforms, and the pulse train of these PI+1M waveforms is the base. The signal is input to the drive section 5. Then, each 1- transistor of the power transistor section 2 is driven by the base drive section 5, and the above +1
Since a pulsed voltage waveform corresponding to the 1jM waveform is applied to the compressor 1, the compressor 1 has uv, v-ti,
1il-U interphase voltage waveform is applied, an approximate sinusoidal current flows through the compressor 1, and the motor of the compressor 1 is driven.

In this way, the memory unit 12 stores one fundamental wave data based on the predetermined sine wave 11 and a carrier wave 2 with a constant frequency.
In order to combine the time data I or ■ based on the fundamental wave data with the time data ■ and ■ corresponding to the operating frequency, step data (reading interval data) for reading the fundamental wave data is provided. There is a plurality of step data for each frequency, and a certain number of step data (
For example, 20 frequencies), the step data are changed stepwise, and finally the step data of the changed frequency is stored in the internal memory RAM10a.

Therefore, when the operating frequency is varied, the carrier frequency remains constant, the interphase voltage waveform applied to the compressor 1 becomes a pulse of several μs, and the resolution of the operating frequency becomes ±0 due to the stepwise change of the step data. Since the frequency increases from .2Hz to ±0.25Hz (in this example) and changes smoothly, the data memory capacity does not increase and the current waveform of the compressor 1 becomes closer to a sine wave. (that is, the distortion of the current waveform becomes smaller), and the harmonic components included in the current waveform are reduced.
The noise of the compressor 1 can be suppressed.

In the above embodiment, the operating frequency is changed in units of 17, but depending on the resolution of the frequency, the operating frequency may be changed in units of ±0.27 to ±0.25 Hz. This allows you to change the frequency more smoothly.

[Effects of the Invention] As explained above, the inverter control device of the present invention divides a predetermined sine wave into equal parts, and superimposes fundamental wave data at the equally divided positions and a carrier wave of a constant frequency on the sine wave. Then, in order to read the time data from the peak or trough of this carrier wave to the position of the carrier wave corresponding to the fundamental wave data and the fundamental wave data according to the operating frequency of the load (compressor), A predetermined number of step data and voltage data for the above-mentioned operating frequency are provided, and when changing the operating frequency of the compressor, a certain number of the above-mentioned step data are read out, read out in stages, and stored in an internal memory RAM. Computing the fundamental wave data and voltage data according to the step data,
Since the time data corresponding to the calculated value obtained as a result is set in real time and the output waveform of the real timer I/O boat is made into a PWM waveform, the memory capacity of the data to obtain the PWM waveform is small. The carrier frequency can be kept constant even when the operating frequency is varied, and the resolution of the operating frequency can be improved.
The frequency can be changed smoothly.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of an inverter control device showing an embodiment of the present invention, FIGS. 2, 6 and 7 are diagrams for explaining calculation of data used in the inverter control device, Figures 3, 4, 5 and 8 are diagrams for explaining the contents of the memory used in the above inverter control device, and Figures 9 and 0 are for explaining the inverter control device. 11 is a schematic block diagram of a conventional inverter control device, and FIG. 12 is a flowchart diagram and a time chart diagram for explaining a method of obtaining data used in the inverter control device of the conventional inverter control device. 13 are diagrams for explaining the contents of a memory used in a conventional inverter control device. In the figure, 1 is a compressor (load), 2 is a power transistor section (several switching elements), 5 is a base drive section, /
O is the control unit (CPU; microcomputer), /Oa
is internal memory RAM (temporary storage means), 11 is a sine wave,
12 is a memory section, 12a is a first memory (for fundamental wave data), 12b is a second memory (for step data), 1
2c is the third memory (for voltage data), 12d is the fourth memory (for time data), 13113a +1.
3b is a carrier waveform.

Claims (1)

[Claims] (1) When controlling a load with an inverter, read waveform data corresponding to the target frequency of the load from memory, obtain a PWM waveform based on the waveform data, and obtain the PWM waveform based on the waveform data.
Switching transistor is turned on/off by WM waveform
In an inverter control device that drives an FF and outputs a voltage waveform to be applied to the load, the electrical angle of a predetermined sine wave is divided into equal parts of 60 degrees, 120 degrees, or 180 degrees, and the height of the sine wave at the equal division positions is determined. a first memory that stores the value of the fundamental wave data as fundamental wave data; a second memory that stores step data for reading out the fundamental wave data corresponding to the operating frequency of the load; a third memory that stores voltage data for adjusting the voltage of the output waveform; a carrier wave having a constant frequency is superimposed on the sine wave, and a carrier corresponding to the fundamental wave data is generated from the peak or trough of the carrier wave; a fourth memory that stores the interval to the wave position as time data; a temporary storage means that stores a fixed number of step data in the second memory according to the operating frequency of the load; and changing the operating frequency. At this time, reading step data from the second memory in units of the certain number of pieces, and
Shifting the step data one step at a time, reading out a fixed number of step data and storing it in the temporary storage means, reading out the fundamental wave data based on the stored step data, and combining the fundamental wave data and the voltage data. and a control means for setting the time data corresponding to the calculated value in an internal real timer every half period of the carrier wave, Timer I/
An inverter control device characterized in that the PWM waveform is obtained by inverting the output of the O port.