JPH04229096A - Method of automatically sensing and controlling frequency of power source - Google Patents

Abstract

PURPOSE: To dispense with changeover switching operation by detecting the frequency of an AC power source and performing the operation geared to it. CONSTITUTION: A source voltage is inputted into a microcomputer 10 as a frequency signal, being half-wave rectified with a rectifier DB and made into pulses by a transistor TR1. The microcomputer 10 decides the power frequency, clocking the frequency signal, with the clock of an oscillator 50 as a reference. Then, it performs the PID computation geared to the power frequency, and performs output to a drive controller 60 with the phase data geared to the result so as to control a motor M.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method of automatically responding to power supply frequency, and in particular, in various devices equipped with a microcomputer, the present invention automatically senses the frequency of AC power input to the device, and The present invention relates to a method for automatically sensing power supply frequency, in which each drive unit related to the frequency is sensed and operated according to the frequency.

0002

[Prior Art and Problems] Various devices that control the phase of an AC power source to control the speed of a motor required for the device, that is,
For example, conventional equipment that controls the drive of motors did not have a means to detect the power frequency, so a separate frequency selection switch was installed and the switch was manually changed by the user. Ta.

However, the above-mentioned method causes a lot of trouble to the user because the user has to check the frequency of the input AC power source and then change the frequency selection switch accordingly. There was a problem. In addition, if the frequency selection switch is changed incorrectly, the equipment will malfunction, so there is a problem that the user will not be able to obtain the desired output.

[0004] A representative example of a method for automatically detecting the power frequency to solve these problems is Japanese Patent Publication No. 33561/1983. This method transforms a power source with a power frequency of 50/60 Hz with a rectangular pulse of the same frequency, configures the signal to be input to a microcomputer, and converts the rising pulse of the signal into a rectangular pulse of the same frequency.
If the frequency is 60Hz, count the time between the next rising pulse or the time between the falling pulse and the next falling pulse.
16.6ms later, the next pulse rises, 50Hz
In the case of , the next pulse rises after 20ms, so it is 16.6ms and 20.0ms after the first pulse rises.
If the next rising pulse occurs after 18.3 ms, which is the intermediate value of , it is determined that the frequency is 50 Hz, and if there is a rising pulse before 18.3 ms, it is determined that the frequency is 60 Hz. This also applies when determining by counting the time between falling pulses. In this way, the microcomputer performs magnetic discrimination between power supply frequencies of 60 Hz and 60 Hz, and the output of the discrimination is used to automate the conversion of the power supply frequency. However, the methods described above are limited to determining the power supply frequency.

[0005]

[Object of the Invention] The present invention has been made in view of the above circumstances, and provides a method for determining the power frequency using a microcomputer built into a device and controlling the speed of a motor in accordance with the power frequency. It is an object.

[0006]

[Means for Solving the Problems] The present invention, which has the above-mentioned object, uses an external interrupt signal supply unit to convert AC power input to a device into a rectangular shape having a constant width and a constant value near zero cross. The rectangular wave is used as an interrupt signal, and the number of clocks is counted while a fixed number of 10 external interrupt signals are input at the zero-crossing start point of the AC power supply, and the count value is a step of sensing the frequency of the AC power supply using the power supply; a step of counting external interrupt signals according to the sensed power supply frequency to perform a clock function; and a step of setting a reference rotation speed according to the sensed power supply frequency; PID (Proportional In) for phase control by rotation speed
tegral Differentiate) and determine whether the PID check is complete.
Accordingly, the steps of inputting phase data to a timer counter and outputting a drive control signal based on the phase data obtained by PID calculation to control the phase of the drive unit are performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for automatically adapting power frequency according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a circuit diagram showing an embodiment of a control device to which the power frequency automatic response method of the present invention is applied. , a power transformer PT that increases the voltage of the AC power input through the power flag PL, a bridge diode BD that rectifies the power induced by the secondary coil of the power transformer PT, and a bridge diode BD that rectifies the radio wave rectified input power. The electrostatic voltage unit 20 is made up of a diode D1, smoothing capacitors C1 and C2, and a regulator (reg) that supplies operating power to the microcomputer 10 and each part of the circuit. Resistor R for inputting the accompanying external interrupt signal
1-R3 and a transistor TR1; a reset unit 40 including a reset integrated element RST for resetting the microcomputer 10; a resistor R4; and a capacitor C3;
an oscillator unit 50 that clocks 0 and inputs it; a buffer BUF that switches the AC power supply and controls the phase of the motor M according to a drive control signal from the microcomputer 10; a port triac PTA; a triac TRA; and a resistor R.
5-R9, and a drive control section 60 made up of capacitors c4 and c5.

[0008] Here, the symbol F is a fuse, and BU
F is an open collector current driven buffer. 2 to 5 are signal flow diagrams illustrating the power frequency automatic adaptation method of the present invention. As shown in FIG. 2, when the operating power is supplied, in the main routine, as the microcomputer 10 is reset by the action of the resent unit 40, an initialization operation is performed in step 100, and in step 101, A timer built into the microcomputer 10 counts a certain period of time, and when an overflow occurs, it determines whether the frequency of the AC power is 50Hz or 60Hz.
A clock interrupt subroutine detects whether the external interrupt signal is applied, and performs a clock function according to the sensed frequency every time an external interrupt signal is applied, and applies phase data to the timer counter according to whether the PID check is completed or not. Allows execution of external interrupt subroutines.

Further, in step 102, in the clock interrupt subroutine, a reference rotation speed set to match 60 Hz is inputted before determining the power supply frequency, and in step 103, the reference rotation speed set to match 60Hz is input. It is determined whether the frequency is 50 Hz or 60 Hz, and if it is 50 Hz, the reference rotation speed is changed in step 104 to match 50 Hz, and if it is 60 Hz, in step 105
The reference rotation speed is maintained as it is.

In step 106, the difference between the input reference rotation speed and the actual rotation speed of the motor M is used to control the motor M.
Step 10: perform PID calculation to control the phase of
If the PID check is completed in step 7, the PID check bit is set, and the process is repeated from step 102, repeating the PID calculation operation every time the motor rotates a certain number of times.

The clock interrupt subroutine, which is permitted in the main routine, is executed if a certain condition (for example, an interrupt may occur every 1 msec) is satisfied, and in the clock routine, The input frequency is sensed as shown in FIG. 3, but in step 201, the rotation speed of the motor is sampled to set a PID completion starting point where the PID check is matched with the reference rotation speed, and in step 202, the frequency It is determined whether sensing is possible, and if not sensing, the external interrupt signal is sampled with the clock interrupt signal in step 203.

To explain this in detail, when an AC power supply as shown in FIG. 6 is input, the external interrupt signal supply unit 30 outputs the
The bridge diode BD applies a radio-rectified induced voltage, and the external interrupt signal supply section 30 converts the signal into a rectangular wave in order to match the motive during phase control and to execute the external interrupt routine. and is applied to the microcomputer 10. That is, the radio wave rectified voltage is divided by resistors R1 and R2,
When applied at the base of the transistor TR1, if the base potential is in a low potential state, the transistor TR1 is conductive and a high potential signal is applied; if the base potential is in a high potential state, the transistor TR1 becomes low as the transistor TR1 is turned off. Since a potential signal is applied to the input terminal IRQ of the microcomputer 10, as shown in FIG. Execute interrupt routine. At this time, the frequency of the rectangular signal is 120Hz when the input frequency is 60Hz, and 100Hz when the input frequency is 50Hz.
It becomes z.

In the microcomputer 10, 680us is input during the time when the 10 external interrupt signals are input.
Clock interrupt signals with a period of ec are counted. In the case of 50 Hz, the time for inputting 10 external interrupt signals is 0.1 sec, so 0.1 (sec) / 680 (USEC) ) = 147.
05882・・・・・・(1) In the case of 60Hz, the time for 10 external interrupt signals to be input is 1
/12sec, so 1/12 (sec)/680
(USEC) = 122,5・・・・・・・・・・・・
(2) Therefore, 50 Hz and 60 Hz are determined by comparing the result of equation (1) with 135, which is the intermediate value of the result of equation (2).

At step 240, the count value is 135.
If the value is higher than that, microcontroller 1
0 is recognized as 50Hz, and in step 205, 50Hz
At the same time as setting the flag F50 to 1, clearing the 60Hz flag F60 to 0, and if it is not 135 or more, setting the 60Hz flag F60 at the same time,
Clear the 50Hz flag F50. When the frequency sensing operation as described above is completed in step 207, the frequency count of the external interrupt signal is stopped and a jump is executed in the clock interrupt subroutine.
), the main routine is further executed, and when the input frequency is sensed in step 202, the main routine is also returned.

On the other hand, the interrupt subroutine permitted in the main routine is executed every time a pulse is input to the input terminal IRQ of the microcomputer 10, but when it is executed simultaneously with the clock interrupt subroutine, the external interrupt subroutine is executed. highest priority. In such an external interrupt routine, as shown in FIG. In step 302, 120 external interrupt signals are counted and 1 second is sensed, and if the frequency is 50 Hz, in step 303, 100 external interrupt signals are counted and 1 second is sensed, and in step 304, seconds, The clock function is performed while increasing the minutes and hours in sequence.

Next, in step 305, when a certain period of time has elapsed since the external interrupt signal was input and the timer counter built in the microcomputer 10 overflows, a timer interrupt subroutine is executed. Allow timer interrupts if possible, and set P when certain predetermined conditions are met.
In step 306, the PI outputs a drive control signal according to the phase data from the ID calculation to enable a timer interrupt subroutine for controlling the motor to be executed.
It is determined whether the D check has been completed, that is, whether the PID calculation operation that is repeated at a constant number of revolutions has been completed. If it has not been completed, the previous phase data is input to the timer counter in step 307, and the PID calculation operation is determined. Upon completion of the check, step 308 inputs new phase data into the timer counter and returns to the current address to jump to the external interrupt subroutine.

At the moment when the motor is turned off by the phase data input to the timer counter from the external interrupt subroutine, the timer interrupt subroutine is jumped to. Then, in step 401, the timer counter value is $FF-$0.
In step 402, the external interrupt signal input to the microcontroller 10 is determined to be the initial time at which the input power supply zero-crosses. At 403, a low potential signal is output through the output terminal (OUT) of the microcomputer 10.

As the low potential signal is input, the buffer (BUF) of the drive control section 60 outputs a high potential signal, so a current flows through the resistor R5, and the light emitting section of the port triac PTA starts to emit light. When light is sensed, the light receiving part of the port triac PTA is made conductive, and a trigger signal is applied to the gate of the triac TRA, so that the triac TRA is made conductive, and AC power is applied to the motor M. In step 404, $FO is placed in the timer counter, and in step 405, after enabling the timer interrupt, the process returns to the address stored in the stack at the time of jumping to the timer interrupt subroutine.

[0019] The above timer counter value is $FF - $0
If the timer interrupt subroutine is increased to 0, the timer interrupt subroutine is executed again, and if it is not the initial time in step 402, the output terminal O of the microcomputer 10 is increased in step 406.
It outputs a high potential signal through the UT and returns to the address stored in the stack at the time of jumping to the timer interrupt subroutine. In this case, the port triac (PTA) will no longer operate due to the low potential signal output from the buffer BUF, so the trigger signal applied to the triac PRA will be cut off, but due to the characteristics of the triac TRA, the AC power supply will cross zero. Since the conduction state is maintained until the zero cross start point, the drive of the motor M is continued until the zero-crossing starting point, and when the above-mentioned routine etc. are carried out, the rotational speed of the motor M is automatically varied according to the input frequency.

[0020]

Effects of the Invention As explained in detail above, the present invention uses software to sense the frequency of the AC power source and perform the associated operations, so that the user can determine the frequency of the AC power source one by one. This not only eliminates the trouble of having to change the frequency selection switch, but also has the effect of preventing equipment malfunctions caused by frequency.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a control device to which the power frequency automatic sensing and control method of the present invention is applied.

FIG. 2 is a signal flow diagram illustrating the power frequency automatic sensing and control method of the present invention.

FIG. 3 is a signal flow diagram illustrating the power frequency automatic sensing and control method of the present invention.

FIG. 4 is a signal flow diagram illustrating the power frequency automatic sensing and control method of the present invention.

FIG. 5 is a signal flow diagram illustrating the power frequency automatic sensing and control method of the present invention.

FIG. 6 is a waveform diagram for explaining the automatic frequency sensing and control method of the present invention.

[Explanation of symbols]

10　Microcomputer 20 Static voltage 30 Supply section 40 Reset section 50 Oscillation section 60 Drive control section

Claims (4)

[Claims] 1. A pulse is generated at each zero cross of the power supply frequency, the pulse is applied to the microcontroller as an external interrupt signal, the interrupt signal is counted, the power supply frequency is determined, and the motor is controlled to match the frequency. In the power frequency automatic detection and control method for controlling the power supply frequency, there is an initialization stage after power is applied, and a clock interface that counts a certain period of time and determines the power frequency when an overflow occurs. a step of allowing an external interrupt subroutine to be executed that calculates phase data for controlling the phase of the motor each time the external interrupt signal is applied; and before determining the power supply frequency in the clock interrupt subroutine. Input the reference rotation speed that matches 60Hz, and set the 50Hz flag and 60Hz in the clock interrupt subroutine above.
According to the Hz flag, the power frequency is 50Hz or
The PID check is completed by determining whether the frequency is 60Hz and adjusting the reference rotation speed to the determined frequency, and calculating the PID to control the phase of the motor according to the input reference rotation speed. A power frequency automatic detection and control method comprising the steps of setting a PID check bit and returning when a PID check bit is detected. 2. The clock interrupt subroutine includes a step of sampling the motor rotation speed in order to set a starting point at which the PID check is completed, and a return to the main routine when the power supply frequency is determined. If it is not determined, the clock is counted while a certain number of interrupt signals are input at each zero-crossing start point of the power supply frequency, and if it is above a certain number, it is judged as 50Hz, and if it is not above a certain number. 50 if
The method of claim 1, further comprising the steps of: determining the frequency in Hz and completing the frequency sensing; and returning after the frequency sensing is completed. 3. The external interrupt subroutine counts external interrupt signals input to the microcomputer, performs a clock function, and counts a certain period of time from the time when the external interrupt signal is input. When the timer counter built into the microcontroller overflows, the timer interrupt subroutine is permitted to be executed, and the PID check bit of the main routine is determined, and when the PID check is completed, the timer interrupt subroutine is allowed to execute. 2. The power supply frequency according to claim 1, further comprising the steps of inputting new phase data to a counter, inputting previous phase data to a timer counter when the PID check is not completed, and returning. Automatic sensing and control methods. 4. The timer interrupt subroutine is a step of prohibiting the next timer interrupt subroutine from starting, and if it is not the initial time at which the power is zero-crossed, the timer interrupt subroutine returns to the main routine and is the initial time at which the power is zero-crossed. In this case, it consists of a step of outputting a low potential to the output port, a step of inputting $FO to the timer counter, and a step of permitting the next timer interrupt subroutine and returning when the timer counter reaches $OO. The power frequency automatic sensing and control method according to claim 1, characterized in that: