JPS61126400A - Control of fan motor for combustion controller - Google Patents

Abstract

PURPOSE:To improve combustion efficiency by judging if the power-source frequency is 50hz or 60hz by a main controller in a feedback control system and changing the method for determining the output data of a fan motor for a set number of revolution according to the above-described judged frequency. CONSTITUTION:The actual revolution speed data of a fan motor 5 is taken into a microcomputer as a main control circuit. In said microcomputer 1, it is judged easily and certainly by the well-known method if the power-source frequency at present is 50Hz or 60Hz. Then, the residual deviation as the differ ence between the actual revolution speed data and a set revolution speed data is obtained in the microcomputer 1, and it is checked if the residual deviation is within an allowable range for the set revolution speed or not. When the residual deviation is outside the allowable range, an aimed revolution speed data corresponding to the power-source frequency is calculated from the residual deviation and the actual revolution speed at this time point, and outputted into the fan motor 5. Therefore, over-shoot, hunting, etc. can be prevented.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a method for supplying an appropriate amount of air to the combustion section according to the amount of combustion required from time to time in a combustion device such as a water heater. , a microcontroller is used as the main control circuit of the feedback control system.
The present invention relates to an improvement in a fan motor control method that uses a computer to control the rotation of a fan motor.

(Prior art) Modern combustion devices for water heaters detect the temperature and amount of water supplied, as well as the temperature of the hot water being tapped, and the user can determine the hot water temperature based on these data. Many devices now have a main controller that controls the temperature as close to the set temperature as possible.

Therefore, in these types of systems, it is necessary to optimally control the tip of the air supplied to one combustion section according to the required combustion amount determined from time to time as described above. Otherwise, not only will the combustion efficiency be reduced, but also the combustion efficiency will be reduced. This is because there is a risk that incomplete combustion will occur.

For this reason, a feedback control system has traditionally been used to control fan motors, and the set rotational speed is sent to the fan motor from the main control circuit, which is generally composed of a microcomputer. The data (target rotation speed data) is compared with the actual rotation speed data sent back to the main control circuit from the Fafun motor via an appropriate rotation speed sensor, and the amount of deviation is compensated for depending on the deviation. A closed-loop configuration is adopted in which the corrected or updated set rotation data is made by adding the following corrections, and is sent again to the fan motor drive circuit.

However, with this type of feedback control system, another thing that must be taken into account is when a combustion device incorporating this control system is configured as a device that is used for power supply frequencies of 50 Hz and 80 Hz.

Conventionally, in order to deal with this, voltage and current data were changed between 50H2 and 60Hz.

Alternatively, for devices using a fan/damper/motor, there were some that changed the position of the fan/damper at the start of operation between 50Hz and 80Hz. However, in the conventional feedback control system as described above, if the voltage and current data are simply changed using the same feedback control system even when the power frequency is changed, the final Even if the optimum air amount is reached, undesirable problems such as overshoot, undershoot, and hunting are likely to occur.

In particular, it is originally desirable to shorten the time required to reach the optimal air volume as much as possible, but the conventional example described above does not have this idea, and from the above, in the end,
Another problem arises in that the pull-in time differs depending on the power supply frequency.

In addition, if the fan/damper/motor is used and the position of the fan/damper is changed, 50Hz and 8
There is still a difference in the time it takes to reach the optimum air amount between 0Hz and 0Hz.

Of course, this is undesirable, especially if the time required to reach the optimum air volume is prolonged, this increases the probability of generating harmful gases and significantly reduces combustion efficiency.
! The present invention has been made to solve these conventional problems, and is intended to enable optimal control depending on the power supply frequency in a feedback control system for a fan motor.

Means for Solving the Problems> In order to achieve the above object, the present invention solves problems such as overshoot, undershoot, and hunting when the actual rotation speed of the fan motor is within the allowable range of the set rotation speed. We focused on the fact that it depends on the method of determining the target rotation speed data (updated set rotation speed data) obtained when the rotation speed is out of range, and the magnitude of the correction amount in the feedback control system.

As a result, the present invention provides a fan/motor control method for a combustion device in which the rotational speed of a fan/motor for supplying an amount of air corresponding to the amount of combustion to a combustion section is controlled by a feedback control system, comprising: The main control device used in the feedback control system determines whether the power frequency is 50Hz or 80Hz, and changes the method of determining output data to the fan motor for the set rotation speed according to the determined power frequency. A method for controlling a fan motor for a combustion control device is provided.

Function> In the present invention, as is obvious from the above configuration, the power supply frequency and the fan of the combustion device that can be used for both 50Hz and 80Hz are
A control circuit that operates optimally as a motor control circuit can be provided.

That is, depending on whether the power supply frequency is 58 Hz or 80 Hz, the method of determining output data itself is changed to be optimal for each frequency, so overshoot, undershoot, hunting, etc. are avoided at any frequency. It is easy to effectively suppress the rotation speed, and the response time until the actual rotation speed of the fan/motor is brought within the allowable range for the set rotation speed is made to be approximately the same length for both station waves. It also becomes easier.

Embodiment Before describing a preferred embodiment of the method of the present invention, a general combustion control device will be briefly summarized and explained with reference to FIG.

The main control circuit 1 includes a water flow sensor 6 installed in the water supply channel.
When the water quantity signal S6 is received from the hot water outlet, a set temperature signal Ss for commanding the desired hot water temperature by the user, a water supply temperature signal S7 from the water supply temperature sensor 7 provided in the water supply channel, and a water supply temperature signal S7 provided in the hot water supply channel are sent. Each of the output hot water temperature signals S8 from the output hot water temperature sensor 8 for detecting a certain actual output hot water temperature is taken in, and the amount of combustion to be given to the combustion section 3 such as a gas burner is calculated from these signals.

Then, according to the result, a gas proportional valve control signal S4 is sent to the gas proportional valve 4 to control the fuel gas supply amount, and
A fan/motor rotation control signal Sc is sent to the fan/motor 5 based on the air supply amount or fan/motor set rotation speed data corresponding to the combustion finish.

From the fan motor 5, fan motor rotation speed data Fr indicating the actual rotation speed is obtained by adding an appropriate sensor to the fan motor 5.
p■ is fed back to the main control circuit, and depending on the deviation between this actual rotation speed data and the previously set rotation speed data,
Feedback control is achieved.

Further, if the combustion amount calculated above exceeds the capacity of the gas burner, the main control circuit 1 outputs a water flow valve control signal SFj, and the water flow valve 9 receives this signal.
Then, the hot water outlet is narrowed down to regulate the amount of hot water coming out.

Of course, the amount of heat generated by the combustion section 3 is transferred to the running water by the heat exchanger 2.

An outline of a basic embodiment of the fan motor control method of the present invention applicable to such a combustion control device is as follows.

First, the actual rotation speed data of the fan motor is input into the microcomputer as the main control circuit.

Next, the residual deviation, which is the difference between the fan/motor rotation speed data and the set rotation speed data, is determined, and it is checked whether this residual deviation is within the allowable range for the set rotation speed, and if it is within the allowable range. If so, the power frequency is 50
Regardless of whether it is Hz or flGHz, the residual deviation is determined by normal feedback control. Depending on the amount of difference, target rotation speed data is created with minute corrections and outputted as output data to the fan motor drive circuit.

On the other hand, when the residual deviation is outside the allowable range, at that point, the target rotation speed data is calculated based on the power supply frequency from the residual deviation and the actual fan motor rotation speed, and this data is used for the fan motor rotation speed.・Output to the motor.

In addition, if the actual fan/motor rotation speed does not fall within the allowable range of the set rotation speed, a correction value is calculated according to the power supply frequency, and the target rotation speed data is changed using the correction value. Outputs to and controls fan motor.

Such a control method can be particularly expressed by a flow chart as shown in FIGS. 1(A) to 1(C) when a microcomputer actually used in modern combustion control devices is applied.

Broadly speaking, there are three routines, as shown in Figure 1 (,A).
is the main routine of combustion control, and (B) of the same figure shows the main routine of combustion control.
The motor rotation speed acquisition routine and the same figure (C) show the fan motor control routine. micro·
The computer processes each routine in time division.

In the main routine, first, it is determined whether the power supply frequency is 50 Hz or 80 Hz by the method shown later in @2[1ffl, and the result is stored in the power supply frequency identification register. Next, as mentioned above, determine the appropriate or necessary combustion amount at that time from the water amount and each temperature information group, calculate the set rotation speed of the fan motor according to the combustion amount, and print the label (SETRPN). Store this in the register indicated by . This operation is repeated, and the contents of the (SETRPM) register are updated each time.

On the other hand, the fan motor rotation speed acquisition routine shown in FIG. 1(B) is executed every time the rising edge or falling edge of the rotation speed signal pulse 5 from the sensor that detects the fan motor rotation speed is detected. , the contents of the register indicated by the label (FMCNTR) are incremented by 1'' each time.

The fan motor control routine shown in FIG. 1(C) is executed at predetermined intervals. However, this certain period of time is set so as to satisfy the condition that the captured rotational speed data can show sufficient resolution in the entire rotational speed range and responsiveness is not impaired.

In this fan motor control routine, first the label (F
The contents of the register indicated by MCNTR) are labeled (FA
After transferring the data to the register indicated by (NRPM), the data is transferred to the register indicated by (FNCN
TR) Clear the contents of the register.

Next, the actual rotation speed (FANRPM) taken in above is subtracted from the set rotation speed (SETRPM) calculated earlier in the main routine shown in FIG. ) stored in a register.

Thereafter, it is checked whether the content of the residual deviation (DINRPM) is zero or not, and if it is '0', the set rotational speed and the taken-in rotational speed are equal, and this routine is then terminated.

If it is not Ooo, it is checked whether the absolute value of the content is larger than a preset constant. Here, the constant 01 indicates the allowable range for the set rotation speed. '(D IFRPM) If the absolute value of the register contents is smaller than the constant C1,
Since the actual rotation speed of the fan motor is within the permissible range of the set rotation speed, clear the contents of the register (HANIIN) that indicates whether it is within the permissible range.
A slight correction is made to the previous output data and the result is output to the fan motor drive circuit, and this routine ends.

The absolute value of the contents of the CDIFRPM) register is the constant C above.
If it is greater than 1, the actual rotation speed of the fan motor is outside the allowable range for the set rotation speed.
(HANIIN) Check the contents of the register.

(HANIIN) If the contents of the register are "θ", it means that the previous rotation speed was within the allowable range, so there is no need for a large correction; After writing “l” to the HA (old IN) register, read the contents of the power supply frequency identification register, and calculate the output data (OUTDAT) corresponding to each power supply frequency as the residual deviation (O
IFRPN), outputs it to the fan motor, and ends this routine.

On the other hand, if the content of the ()IANIIN) register is l'', it means that the previous rotation speed taken in was also outside the allowable range.In other words, the actual rotation speed of the fan motor is still below the set rotation speed. This indicates that the power supply frequency is not within the allowable range, so an appropriate correction value (
Calculate CO to PEN).

If the actual fan motor rotation speed is higher than the set rotation speed, the new output is calculated by subtracting the above correction value (60MPEN) from the previous output data (OUTDAT) in the previous fan motor control routine. Data (O
On the other hand, if the actual rotation speed of the fan motor is lower than the set rotation speed, the output data (OUTDAT) is output to the fan motor as 8 times output data (OUTDAT).
The correction data (COMPEN) is added to T) to create new output data (OUTDAT), which is output to the fan motor, and this routine ends.

As for the method of determining whether the power supply frequency is 50 Hz or 80 Hz, those skilled in the art can construct various circuit configurations using known and existing electronic circuit technology.

For reference, two methods proposed by the present applicant are shown in Fig. 2.-First, the method shown in Fig. 2 (A) uses a commercial AC power source to drive a combustion device incorporating the present control circuit. A, C, 100V is stepped down to an appropriate voltage v1 via a transformer 10, etc., and rectified by a rectifier circuit 11, and then the pulsating voltage as a result of the rectification is connected to resistors R1 and R2, if necessary. The potential of an appropriate voltage division ratio is lowered to a lower appropriate voltage value range using a meter, and then inputted to the base of the transistor Tr.

Therefore, this transistor Tr repeatedly turns on and off synchronously due to the pulsating voltage, so that its collector output oscillates between the power supply potential Vcc and approximately C ground potential.

Therefore, the microcomputer 1 as the main control circuit
Now, by measuring the pulse width or cycle time of this oscillation pulse, you can easily and reliably determine that the current power supply frequency is 5.
It can be determined whether the frequency is 0Hz or 80Hz.

The method shown in FIG. 2(8) uses a comparator 12 in place of the transistor T''.The operation is almost the same as when a transistor is used.

In other words, one input of the comparator 12 is connected to the resistor R3 and R
4, and set the resistor R1 to a suitable reference voltage value of
The pulsating voltage divided by and R2 is applied to the value input of the comparator.

Therefore, every time the pulsating current voltage crosses the reference voltage value, the output of the coverator 12 is inverted, and between one inversion and the next inversion, a logic "H" pulse width synchronized with the power supply frequency is generated. Pulse to logic "I, I?" A pulse begins to occur.

Therefore, by using this and performing the same process as when using the above transistor, the microcomputer 1 can:
The power frequency currently applied to the device is 50Hz,
It is possible to easily determine which frequency of 80 Hz it is.

Of course, the illustrated transformer 1O does not need to be provided exclusively for such power frequency identification, and may be used as a control circuit or a transformer provided in the power supply section of a combustion device in which this control circuit is incorporated. It can be configured as a part of the power supply unit.

<・Effect of the invention> According to the invention, the power frequency is 50Hz or 80Hz.
As a method of controlling a fan motor for a combustion device that is configured as a shared device, it is possible to perform optimal control according to each power supply frequency.

In particular, it is easier to create an optimal design to prevent overshoot, undershoot, hunting, etc.
The response time required to bring the actual rotation speed of the fan motor into the allowable range of the set rotation speed can be made constant regardless of the power supply frequency. Therefore, the release of gases harmful to the human body can be prevented. This can be prevented with a high degree of certainty, and combustion efficiency can also be maintained at a good level. !

[Brief explanation of drawings]

FIG. 1 is a flow chart of an embodiment of the fan motor control method of the present invention, which is optimal when using a microcomputer, and FIG. 2 is a schematic configuration diagram of a reference example of a power supply frequency identification method. FIG. 3 is a schematic diagram of an example of a general combustion apparatus to which the method of the present invention can be applied. In the figure, ■ is a microcomputer as the main control circuit, 2 is a heat exchanger, 3 is a combustion section such as a gas burner, 4 is a gas proportional valve, 5 is a fan motor, 6 is a water flow sensor, and 7 is a supply Water temperature sensor, 8 is hot water temperature sensor, 9 is water flow valve, 1
0 is a transformer, U is a rectifier circuit, 12 is a comparator, T
r is a transistor, and R1, R2, R3, and R4 are resistors.

Claims (1)

[Scope of Claims] A method for controlling a fan/motor for a combustion device in which the rotational speed of a fan/motor for supplying an amount of air corresponding to the amount of combustion to a combustion section is controlled by a feedback control system, the feedback control system described above. The main control device used in the system determines whether the power frequency is 50Hz or 60Hz,
A method for controlling a fan motor for a combustion control device, characterized in that a method for determining output data to the fan motor for a set rotational speed is changed in accordance with the determined power supply frequency.