JPH04134506A - Method for controlling phase controller - Google Patents

Abstract

PURPOSE:To exactly control the phase of a controlled system with high accuracy even when a power supply frequency is fluctuated by correcting a PWM signal for operation by measuring a wave height range corresponding to a maximum wave height value. CONSTITUTION:The wave height range corresponding to the maximum wave height value of a lamp voltage is measured by a trigger signal generation circuit 13 and a measuring signal output circuit 17, and the frequency of a power supply voltage is indirectly measured. In this case, a control circuit 9 stores the contents of the PWM signal corresponding to an inputted measuring signal into a RAM 9c and outputs the PWM signal with the stored PWM signal contents as the 100% operation output range. Further, the output of an output inhibiting signal is stopped so as to output a trigger signal from an output switching circuit 15 to an operation output circuit 19, and the operation output circuit 19 outputs the power supply voltage to a heater from the output of the trigger signal to the turn of this signal to 0 level in each half cycle period of the power supply voltage. Thus, even when the power supply frequency is fluctuated, the phase of the controlled system can be exactly controlled with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of controlling a phase control controller, for example, a phase controller that controls the phase of operating power to a heater, such as a temperature controller. This invention relates to improvements in control methods used in control controllers.

[Prior Art] Conventionally, in this type of phase control controller, as shown in FIG. 6, a control circuit 1 controls a set value sv and a molding machine (not shown).
For example, a PID calculation is performed on the manipulated variable from the measured value PV of temperature sensors placed at the same location, and a PWM (pulse width modulation) signal is converted and output.The PWM/voltage conversion circuit 3 converts the PWM signal into a DC level control voltage. The trigger signal generation circuit 5 oscillates a lamp voltage (sawtooth voltage) in synchronization with the power supply voltage to the heater (not shown) of the molding machine, compares the level with the control voltage, and determines whether the lamp voltage is lower than the control voltage. When the power supply voltage becomes high, a trigger signal is output, and the operation output circuit 7 outputs power to the heater until the power supply voltage reaches O level according to the trigger signal during each half cycle period of the power supply voltage.

That is, as shown in FIG. 7A, the control circuit 1 outputs the manipulated variable as a PID calculation result as a PWM signal with a varying duty ratio during one cycle, and as shown in FIG. 7B, the PWM signal is output with the duty ratio changed. -Convert the control voltage to a DC level control voltage according to the ratio, and then compare the level of the lamp voltage synchronized with the frequency of the power supply voltage (C in the same figure) and the control voltage level as shown in the same figure.The lamp voltage is higher than the control voltage. The control method was to output a trigger signal when the power supply voltage reached the O level, and output the power supply voltage to the heater during each half-cycle period of the power supply voltage from the time the trigger signal was output until the power supply voltage reached the O level, as shown in E and F in the same figure. .

The PWM signal in Figure 7A becomes the inverted output and becomes the PWM signal.
When the output is 80% and the duty ratio is 1:4, and the control voltage in Figure B is set to a voltage level of 0 to 5V, Ov is converted to the operation amount 100%, 5V is converted to the operation amount O%, and the PWM signal is controlled. 80% of the amount is converted to 1■.

The same applies to the following explanation.

Therefore, in such a control method, if the frequency of the power supply voltage is, for example, 50Hz, the maximum peak value of the lamp voltage will be the seventh
As shown in the figure, it becomes a fixed value synchronized with 50 Hz, and the maximum wave height value can be fixedly determined as 0% of the operation output to the heater.

Therefore, the wave height range of the lamp voltage can be adjusted by the manipulated variable 0 to 10.
If the PID calculation is performed with 0%, the phase of the heater can be accurately controlled by comparing the lamp voltage with the control voltage created based on the PWM signal.

[Problems to be Solved by the Invention] However, when the frequency of the power supply voltage changes from, for example, 50 Hz as shown in the solid line to 60 Hz as shown in the dashed dot line as shown in FIG. 8A, the lamp voltage changes from the solid line state to the dashed dotted line as shown in FIG. The maximum peak value of the lamp voltage decreases, and the phase control range for the heater narrows from E50 to E60. That is, phase control for ΔE (where Δ is time) cannot be performed.

Therefore, even if the heater is accurately phase-controlled with a power supply voltage of 50Hz, when the frequency of the power supply voltage changes to 60Hz, the operation method tends to be inaccurate.In order to ensure accurate phase control, it is necessary to adjust the power supply frequency. The calculation of the PWM signal must be corrected in accordance with the change, in other words, the change in the maximum peak value of the lamp voltage, and special measures are required.

Furthermore, although it is not impossible to correct for use in areas where different frequencies are known in advance, there is a drawback that it cannot be corrected when the predetermined power supply frequency varies.

The present invention has been made to solve these conventional drawbacks, and even if the power frequency of the area where the phase control controller is used fluctuates, it is possible to accurately and highly precisely phase control the controlled object, and the power source The present invention provides a control method that can be used in areas with different frequencies without considering the frequency difference.

[Means for Solving the Problems] In order to solve such problems, the present invention calculates the operation amount from the set value and the measured value from the controlled object,
Output as a WM signal, create a DC level operation control signal according to the duty ratio of this operation PWM signal, and generate a ramp signal with a constant slope and synchronized with the frequency of the power supply signal and the level of the operation control signal. This is a control method for a phase control controller in which the control target is operated and controlled by a power supply signal only during the period of the ramp signal that exceeds the operation control signal by comparing the The operation PWM signal is corrected by using the wave height range as the 100% operation output range to the controlled object.

And, the present invention can measure P from a high level or a low level.
A control signal for measurement is created by sequentially changing the WM signal with a predetermined resolution, and each of these control signals for measurement is compared with the maximum peak value of the ramp signal, and the control signal for measurement is determined to be the maximum peak value. It is also possible to measure the wave height range based on whether or not the wave height range exceeds the range, and to correct the operation PWM signal by using the content of the measurement PWM signal at the time of this measurement as the 100% operation output range to the controlled object.

Furthermore, the present invention provides the above-mentioned PWM signal for operation and PWM signal for measurement.
A control method may be used in which the M signal, the operation control signal, and the measurement control signal are the same.

[Function] In the present invention equipped with such a means, when the frequency of the power signal changes, the maximum peak value of the lamp signal changes, and the pulse height range corresponding to the maximum peak value is measured to generate the PWM signal for operation. Since the correction calculation is performed, even if the power supply frequency fluctuates, the operation PWM signal is always calculated and output within the range of 100% operation output to the controlled object.

In the method of creating a measurement control signal from the measurement PWM signal, measuring the wave height range of the lamp signal, and calculating the operation PWM signal, the operation PWM signal is calculated and the control target is constantly controlled. The operation PWM signal is corrected and calculated.

Furthermore, in the method in which the operation PWM signal and the measurement PWM signal, and the operation control signal and measurement control signal are the same,
Part of the configuration of the phase control controller can be shared, and the difference in lamp signals between operational control and measurement is small.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

For convenience, a phase control controller that implements the control method of the present invention will be described first.

FIG. 1 is a block diagram showing the main parts of a phase control controller that implements the control method of the present invention.

In the figure, the control circuit 9 includes, for example, a CPU 9a having a PID calculation function and other known calculation functions;
It has a ROM 9b containing the operating program of a, a RAM 9c that stores calculation results and other data, and an input/output signal interface l10 (not shown), and temperature sensors (not shown) distributed at multiple locations of the control target. The measured value PV from (not shown) and the set value SV from the outside can be manually input, and the manipulated variable is PID calculated from the measured value PV and set value Sv, and the duty during one cycle is adjusted according to the manipulated variable. - serves as an arithmetic means for outputting a PWM signal with a changed ratio to the PWM/voltage conversion circuit 11.

The PWM/voltage conversion circuit 11 is a control signal generating means that converts the PWM signal into a DC level control voltage according to the duty ratio and outputs it to the trigger signal generation circuit 13 (see FIG. 7).

As shown in FIG. 2, the trigger signal generation circuit 13 internally oscillates a lamp voltage that has a constant slope and is synchronized with a half cycle of the frequency of the power supply voltage, compares this lamp voltage with the level of the control voltage, and generates a lamp voltage. Positive (+) and negative (
-) to the output switching circuit 15 and the measurement signal output circuit 17.

The output switching circuit 15 switches the output of the trigger signal from the trigger signal generation circuit 13 to the operation output circuit 19, and as described later, the output of the trigger signal to the operation output circuit 19 is controlled by an output prohibition signal from the control circuit 9. This is to turn off the output. Note that the trigger signal to the output switching circuit 15 is output at, for example, a positive (+) level as shown in FIG.

The operation output circuit 19 is an operation output means that outputs a power supply voltage to a heater (not shown) as a controlled object during each half-cycle period of the power supply voltage from when the trigger signal is output until the trigger signal becomes 0 level.

The measurement signal output circuit 17 takes the logical sum of the positive (+) and negative (-) trigger signals from the trigger signal generation circuit 13, and if the logical sum is "1", the control circuit uses this as a measurement signal (+). 9.

The control circuit 9 has a power supply voltage frequency confirmation mode and a non-frequency confirmation mode, and these modes can be switched and set using a keyboard switch or the like disposed on the main body panel of the phase control controller.

As shown in FIG. 6, the non-frequency confirmation mode is a mode in which the manipulated variable is PID calculated from the set value SV and measured value PV, converted to a PWM signal, and outputted to the PWM/voltage conversion circuit 11. This is similar to the control circuit in a phase control controller.

In the frequency confirmation mode, the trigger signal generation circuit 13 was initially used.
PW with a duty ratio such that the control signal has a level greater than, for example, the maximum peak value of the trigger signal that can be generated.
The M signal is decreased by 5 mV at a resolution of, for example, 30 m5ec, and is sequentially output until the measurement signal is output from the measurement signal output circuit 17, and when the measurement signal is input, the control circuit 9 outputs the PWM signal corresponding to the measurement signal. P for operation with level as 100% operation output range to heater
This is a mode in which the WM signal is corrected and output, and 1II
The J111 circuit 9 serves as this correction calculation means. Note that the 100% operating output range is the effective output range.

Furthermore, an output prohibition signal is output to the output switching circuit 15 so that the trigger signal is not output to the operation output circuit 19 until the PWM signal for operation is output.

Next, the control method according to the present invention will be explained while explaining the operation of such a phase control controller.

FIG. 3 shows a flowchart showing the operation of the phase control controller.

When the program starts, it is determined in step 301 whether the mode is frequency confirmation mode, and if YES, an output prohibition signal is output to the output switching circuit 15 in step 302, and in step 303, the maximum peak value of the trigger signal is A PWM signal with a manipulated variable that results in a control signal with a high level, that is, a level higher than 0% of the manipulated output to the heater is set.

In step 304, the high-level PWM signal shown in FIG. Figure 2C)
are compared and the process moves to step 307.

In step 307, it is determined again whether or not it is the frequency confirmation mode. If YES, it is determined in step 3.8 whether or not the lamp voltage is equal to or higher than the control voltage. If NO, the process returns to step 301 and steps 301 to 301 are performed. 308 is repeatedly processed, and each time the process is repeated, a PWM signal that sequentially lowers the level of the control voltage as shown in FIG. 2B is calculated and output.

When the control voltage falls below the maximum peak value of the lamp voltage and step 308 becomes YES at point P in FIG. 2, step 3
At 09, the trigger signal generation circuit 13 instantaneously outputs a positive (+) or negative (-) trigger signal to the measurement signal output circuit 17 in accordance with the half cycle of the power supply voltage shown in FIG. 2A (FIG. 2D).
, and in step 310, the positive (+) or negative (=) values are logically summed and a measurement signal as shown in E of the figure is outputted to the control circuit 9.

That is, the trigger signal generation circuit 13 and the measurement signal output circuit 17 measure a wave height range corresponding to the maximum wave height value of the lamp voltage, thereby serving as a measuring means for indirectly measuring the frequency of the power supply voltage.

In step 311, the PW corresponding to the input measurement signal is
The control circuit 9 stores the M signal contents (level) in the RAM 9c, and in step 312, the control circuit 9 stores the stored PW
The PWM signal is output with the M signal content set to 100% of the operation output range, and the output of the output prohibition signal is stopped so that the trigger signal can be output from the output switching circuit 15 to the operation output circuit 19, and the operation output circuit 19 In each half-cycle period of the voltage, the power supply voltage is output to the heater from the time when the trigger signal is output until the trigger signal reaches the O level.

That is, the control circuit 9 also functions as a correction calculation means.

If it is the non-frequency confirmation mode and step 301 is No, a PWM signal for operation is calculated and output in step 313, and the process moves to step 304. If step 307 is No, the lamp voltage is changed to the control voltage in step 314. It is judged whether or not it is above, and the answer is N.

If YES, step 315 outputs a trigger signal, and step 316 outputs the power supply voltage to the heater from the time the trigger signal is output until it becomes 0 level.

The present invention corrects the control method using the frequency confirmation mode described above, and calculates the measured value PV and set value S
The manipulated variable is calculated from and converted to a PWM signal and output, and this P
Create a control voltage according to the duty ratio of the WM signal,
The control method is based on a control method in which a lamp signal synchronized with the frequency of the power supply voltage is compared with the level of its control voltage, and the heater is operated and controlled by the power supply voltage only during the period when the lamp voltage exceeds the control voltage. This method measures the corresponding wave height range, defines the wave height range of the lamp voltage from the PWM signal at the time of outputting the measured signal, and corrects the PWM signal for operation as the 100% operation range for the heater.

Moreover, the PWM signal is initially changed from a high level to a PWM signal for measurement at a predetermined resolution to create a control voltage for measurement, and the maximum waveform of the lamp voltage is generated for each of these control voltages for measurement. The peak range of the lamp voltage is measured using the measurement signal when the control voltage for measurement exceeds the maximum peak value by comparing with the high value, and the contents of the PWM signal for measurement at this time of measurement are operated as the 100% operation output range to the heater. In this method, the PWM signal and the control voltage are both used for measurement when measuring the wave height range of the lamp voltage, and after the measurement, they are changed to use for operating the heater.

In the present invention, the frequency of the power supply voltage is indirectly measured from the peak value of the lamp voltage that changes in accordance with the frequency of the power supply voltage, and the PID calculation is corrected based on this measurement result.
By converting and outputting the WM signal, accurate phase control is possible even when the frequency of the power supply voltage changes.

For example, as shown in FIG.
If the operating output at a power supply voltage of 50Hz is set to 100% in the range of 10% to 90% with a margin of 10% above and below %, when the power supply voltage becomes 60Hz, the range of 10% to less than 90% of 100% of the PWM signal output The PWM signal is corrected and calculated by setting the operation output (the range indicated by the one-dot chain line or two-dot chain line in the figure) as 100%.

By the way, when the operation output is 80%, (100-8
0) X ((90-10) /100)+10=26
% PWM signal output, and if the operation output is X% and the upper and lower margin values are A and B, (100-x) x ((A-B) /1001 +B
This is the PWM signal output.

Moreover, when implementing the control method of the present invention, the conventional circuit configuration can be used as is, and there is little need to change the internal configuration of the phase control controller.

In addition, if the PWM signal and control voltage are used for measurement when measuring the wave height range of the lamp voltage, and then changed to the heater operation after measurement, the circuit configuration can be shared, and the circuit configuration can be shared between measurement and operation control. The advantage is that there is less lamp voltage error.

Therefore, not only can the same phase control controller be used in areas with different frequencies, but also stable phase control can be achieved even under power sources with varying frequencies.

By the way, in the above-mentioned configuration, the PW for measurement starts from a low level.
A configuration may also be used in which the M signal is sequentially changed to a high level and output, and the wave height range is measured when the measurement control signal exceeds the maximum wave height value of the lamp voltage.

FIG. 5 shows a block diagram of a phase control controller for implementing another embodiment of the present invention.

In this configuration, a PWM/voltage conversion circuit 3 forming the conventional phase control controller described above, a signal generation circuit 5 and an operation output circuit 7 are connected to the control circuit 9. It is configured by connecting the PWM/voltage conversion circuit 11, trigger signal generation circuit 13, and measurement signal output circuit 17 shown in FIG. 1, and the operation output switching circuit 15 is omitted.

In this configuration, the control circuit 9 converts the PWM signal for operation into PWM
The control circuit 9 outputs the signal to the M/voltage conversion circuit 3, outputs the trigger signal from the trigger signal generation circuit 5 to the operation output circuit 7, outputs the operation output to the controlled object, and performs phase control. The PWM signal is output to the PWM/voltage conversion circuit 11, and when the signal generation circuit 13 outputs a trigger signal to the measurement signal output circuit 17 and the measurement signal is input to the control circuit 9, the control circuit 9 Based on the PWM signal for measurement, a PWM signal for operation is corrected and output.

The control method for the phase control controller with this configuration is that the control circuit 9 outputs a PWM signal for operation, and the PWM signal for operation is
While controlling the phase of the controlled object based on the M signal, in parallel, the control circuit 9 outputs a PWM signal for measurement to measure the wave height range of the trigger signal, and outputs a PWM signal for measurement corresponding to the measurement signal. Based on this, the PWM signal for the operation is corrected and calculated.

In such a control method, the frequency is measured while controlling the phase of the controlled object, and it is possible to correct the PWM signal for operation in real time even in areas where the frequency stability of the power supply voltage is poor. Phase control can be performed accurately and with high precision at all times.

In this control method, the operation PWM signal may always be corrected based on the measurement results, but it is preferable to perform the correction calculation based on the average value of a plurality of measurement results of the measurement PWM signal during each measurement.

It should be noted that although it is expected that the peak values of the operating lamp voltage and the measuring lamp voltage may not match, the levels may be adjusted appropriately at the time of shipment or thereafter.

[Effects of the Invention] As explained above, the control method of the present invention enables accurate and high-precision phase control of the controlled object even if the power frequency in the area where the phase control controller is used fluctuates, and It can be implemented as is even in different regions without considering the frequency difference.

Moreover, in the method of creating a measurement control signal from a measurement PWM signal, measuring the wave height range of a lamp signal, and calculating an operation PWM signal, the operation PWM signal is calculated and the control target is controlled. However, there is an advantage that the operation P and WM signals are always corrected.

Furthermore, in the method in which the operation PWM signal and the measurement PWM signal, and the operation control signal and measurement control signal are the same,
In addition to making it possible to partially share the configuration of the phase control controller,
The difference in lamp signals between operation control and measurement is small, allowing highly accurate phase control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of a phase control controller that implements the control method according to the present invention, FIG. 2 is a waveform diagram explaining the operation of the phase control controller shown in FIG. 1, and FIG. FIG. 4 is a flowchart explaining the operation of the phase control controller of FIG. 1, FIG. 4 is a diagram explaining the operating range according to the present invention, and FIG. 5 shows a phase control controller for implementing another embodiment of the present invention. FIG. 6 is a block diagram showing a phase control controller implementing a conventional control method, and FIGS. 7 and 8 are waveform diagrams illustrating the operation of the phase control controller shown in FIG. 6. 1.9... Control circuit 3.11... PWM/voltage conversion circuit 5.13.
Trigger signal generation circuit for...7.19 Operation output circuit for...

Claims (3)

[Claims] (1) Calculates the manipulated variable from the set value and the measured value from the controlled object and outputs it as an operating PWM signal.
A control signal for operation at a DC level is created according to the duty ratio of the WM signal, and the level of the control signal for operation is compared with a ramp signal whose slope is constant and synchronized with the frequency of the power supply signal, and the control signal for operation is determined. A method for controlling a phase control controller in which the controlled object is operated and controlled by the power supply signal for a period of the ramp signal exceeding the period of time, comprising: measuring a wave height range corresponding to a maximum wave height of the ramp signal; and using the measured wave height range as the control object. A method for controlling a phase control controller, comprising performing a correction calculation on the operating PWM signal as a 100% operating output range. (2) Create a measurement control signal by sequentially outputting a measurement PWM signal with a predetermined resolution from a high level or a low level,
Each of these measurement control signals is compared with the maximum wave height value of the ramp signal, and the wave height range is measured depending on whether or not the measurement control signal exceeds the maximum wave height value, and the measurement PWM at the time of this measurement is 100 of the signal content to the control target
2. The method of controlling a phase control controller according to claim 1, wherein the operating PWM signal is corrected as a % operating output range. (3) Claim 1 in which the operating PWM signal and the measuring PWM signal are the same, and the operating control signal and the measuring control signal are the same.
A method of controlling the phase control controller described above.