JP3087542B2 - Heater current detection control device for air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater control device provided in an air conditioner, and more particularly to a control for detecting a heater current.

[0002]

2. Description of the Related Art In general, a heater mounted on an air conditioner is often provided as auxiliary heating in addition to a heating heat pump operation of the air conditioner.

This heater has a surface temperature of 30 when energized.
Since the temperature rises to 0 to 600 ° C., safety protection is provided. As a countermeasure, a method of attaching a thermal fuse or the like has been generally used. Further, as a countermeasure as a control device, a method of monitoring an energized state while detecting a heater current was also common. As shown in FIG. 10, the control method sets the heater current detection point in advance, and if the heater current is below the set point after the heater is turned on, it is determined that the heater is disconnected. If the above is the case, the control is to determine that the heater is abnormal. As described above, the above control is the heater current detection control on the premise that the heater operates at the predetermined power value.

[0004]

A problem in this conventional example is that if the heater current is higher than a set point after the heater is turned on, it is determined that the current is normal. For example, if a heater having an extremely low resistance value is erroneously attached, the current may flow excessively and become dangerous, but the control is determined to be normal. The same can be said for a short-circuit failure of the heater after the heater is turned on.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to detect a wrong connection of a heater having a different input or a short-circuit failure of a heater with high accuracy.

It is another object of the present invention to reliably detect a change in the temperature characteristic of the heater.

In addition, when the power supply frequency is 50 Hz and 60 H
It is also an object to reliably detect a change in the area of z.

In addition, when the power supply voltage is 100V and 200V
It is also an object of the present invention to surely detect the heater for use.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a heater, a current transformer for detecting a current of the heater, an ON / OFF state of the heater in an indoor unit main body of the air conditioner. OFF means and a control unit for inputting a converted voltage of the current transformer are provided. Timer means, first setting means, and second setting means are provided in the control unit for judging a heater current.
The setting means is set at a higher setting than the first setting means. When the heater is ON, if the heater current is within the range between the first setting means and the second setting means, the heater is kept ON and the heater current is set to the first setting means. And a control device provided with a means for turning off the heater after a predetermined time if it is out of the range of the second setting means.

In order to determine the heater current in the control section, a timer means, a first setting means, and a second setting means are provided, and the second setting means is set higher than the first setting means. At the time of ON, the control device is provided with a means for shifting the set value of the first setting means and the set value of the second setting means to a lower side after a certain time after the heater current reaches the first setting means or more.

In order to determine a heater current in the control section, a power supply frequency detecting means, a first setting means, a second setting means, a third setting means and a fourth setting means are provided. Is higher than the first setting means and the fourth
The setting means has a lower setting than the second setting means, and the third setting means has a lower setting than the first setting means. When the power frequency is 60 Hz, only the first setting means and the second setting means are valid. And when the power supply frequency is 50 Hz, the third setting means,
This is a control device provided with means for enabling only the fourth setting means.

In order to determine a heater current in the control unit, a power supply voltage detecting means, a first setting means, a second setting means, a fifth setting means and a sixth setting means are provided, and the second setting means is provided. Is set higher than the first setting means, the sixth setting means is set lower than the second setting means, and the fifth setting means is set lower than the first setting means.
At the time of 00V, only the first setting means and the second setting means are enabled, and when the power supply voltage is 200V, the control device is provided with means for enabling only the fifth setting means and the sixth setting means. is there.

[0013]

According to the present invention, since the heater current is determined to be normal only within the range between the first setting and the second setting by the above-described configuration, a dangerous state such as incorrect connection of a different input heater or short-circuit failure of the heater can be quickly determined. Can be found.

In addition, since the first and second settings are shifted to the lower limit after a predetermined time from when the heater current reaches the first setting or more, a normal judgment range in which the temperature characteristics of the heater are taken into account can be maintained accurately. .

When the power supply frequency is 60 Hz, only the first setting and the second setting are valid, and the power supply frequency is 50 Hz.
In some cases, only the third setting and the fourth setting are valid, so that an accurate normal determination range can be maintained in consideration of regional differences in power supply frequency.

When the power supply voltage is 100 V, only the first setting and the second setting are valid. When the power supply voltage is 200 V, only the fifth setting and the sixth setting are valid.
An accurate normal determination range can be maintained for the heaters for 100 V and 200 V.

[0017]

An embodiment of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 is a sequence diagram of an air conditioner equipped with a heater. In FIG. 1, reference numeral 1 denotes a control unit for performing heater control. Reference numeral 3 denotes a heater, and reference numeral 2 denotes a current transformer that detects a current of the heater and converts the current into a voltage. Reference numeral 4 denotes a heater relay for turning on / off the heater. Reference numeral 7 denotes a load for an air conditioner that includes a four-way valve, an outdoor fan, a compressor, an indoor fan, and the like. Reference numeral 5 denotes an air conditioner relay for turning on / off the air conditioner load. 6 is commonly used 100V or 200V
Power supply. FIG. 2 is an electronic circuit diagram of the control unit 1 provided in the air conditioner body of FIG. In the figure, reference numeral 8 denotes a rectifier which converts a heater current flowing through the current transformer 2 into a DC voltage. The smoothing capacitor 10 smoothes the DC voltage of the rectifier 8. Reference numeral 9 denotes a level adjusting resistor for determining the ratio between the heater current and the DC voltage of the rectifier 8. 12 is a CPU
The DC voltage of the rectifier 8 is input to the analog input port 11. Reference numeral 13 denotes a transistor 1, which operates the heater relay coil 4a according to an instruction from the CPU 11. 14
Is the power frequency detection circuit and the signal of 50Hz / 60Hz is C
It is input to PU11. Reference numeral 15 denotes a power supply voltage detection circuit.
A signal of 0 V / 200 V is input to the CPU 11. The control based on the configuration shown in FIGS. 1 and 2 will be described. When the heater relay is ON, the heater current flows through the current transformer 2 and is input to the CPU 11 in the control unit 1 as a converted voltage. At this time, since the CPU 11 previously stores the first setting and the second setting higher than the first setting as the absolute value as the heater current determination, the input converted voltage value is equal to the first setting and the second setting. Heater O within the setting range
N, and if the heater current is out of the range between the first setting and the second setting, the heater is turned off after a certain time (T1).
F.

FIG. 3 shows the heater current and C of the first embodiment.
FIG. 7 is a correlation diagram illustrating a relationship between conversion voltages to an analog input port of a PU11.

FIG. 4 is a timing chart showing the control contents of the first embodiment. As described above, according to the first embodiment, as the heater current determination, the first setting and the second setting higher than the first setting can be stored as absolute values. Within the first
If the setting and the second setting are determined, it becomes possible to detect erroneous connection of a different input heater, short-circuit failure of the heater, and the like.

Next, a second embodiment will be described with reference to FIG. Since the sequence diagram of the air conditioner of the second embodiment and the electronic circuit diagram in the control unit 1 are the same as those of the first embodiment, the description of the configuration is omitted.

FIG. 5 is a timing chart showing the control contents of the second embodiment. In the same drawing, as in the first embodiment, the first setting and the second setting are stored as absolute values so as to fall within the normal range, and when the heater relay is ON,
A certain time after the heater current reaches the first setting (T
2) The first setting and the second setting are shifted to the lower
The setting and the 2a setting are stored and changed.

As described above, according to the second embodiment, after the heater current reaches the first setting, the normal range shifts to the lower limit after a certain period of time. (A tendency that the current value increases and the current value decreases) can be set.

Next, a third embodiment will be described with reference to FIGS. Since the sequence diagram of the air conditioner of the third embodiment and the electronic circuit diagram in the control unit 1 are the same as those of the first embodiment, the description of the configuration is omitted.

FIG. 6 shows the heater current and the CPU of the third embodiment.
FIG. 11 is a correlation diagram illustrating a relationship between a conversion voltage to an analog input port of No. 11 and a power supply frequency. As is apparent from FIG.
At 0 Hz, the voltage applied to the analog input port at the same heater current is lower than at 60 Hz. This is because the smoothing time of the smoothing capacitor 10 is longer at 50 Hz (17.6 msec / cycle at 60 Hz, 5 Hz).
At 0 Hz, one cycle is 20 msec). FIG. 7 is a timing chart showing the control contents of the third embodiment. In the drawing, at 60 Hz, the first setting and the second setting are stored as absolute values so that the normal range is within the range of the second setting as in the first embodiment. Is stored as an absolute value so that the range within the fourth setting becomes a normal range.

As described above, according to the third embodiment, the normal setting of the heater current can be set in accordance with the 50 Hz / 60 Hz area.

Next, a fourth embodiment will be described with reference to FIGS. Since the sequence diagram of the air conditioner of the fourth embodiment and the electronic circuit diagram in the control unit 1 are the same as those of the first embodiment, the description of the configuration is omitted.

FIG. 8 shows a power supply voltage of 100 V and 200 V when assuming the 250 W heater of the fourth embodiment.
It is a comparison table of the heater resistance value and the heater current value in the application. As is clear from the figure, the heater for 100 V flows twice the current of 200 V. FIG. 9 is a timing chart showing the control contents of the fourth embodiment. In the figure, at the time of 100 V, as in the first embodiment, the first setting and the second setting are stored as absolute values so that the range of the second setting becomes a normal range. Is stored as an absolute value so that the range within the sixth setting becomes a normal range.

As described above, according to the fourth embodiment, the normal setting of the heater current can be set in accordance with the 100 V / 200 V specification.

[0029]

As is clear from the above embodiment, the present invention determines that the heater current is normal only within the range of the first and second settings, and thus can prevent incorrect connection of different input heaters or short-circuit failure of the heater. Dangerous conditions can be detected early. Therefore, the contribution to safety can be expected.

In addition, since the normal range is shifted to the lower limit after a certain period of time after the heater current reaches the first setting, variations in the temperature characteristics of the heater can be absorbed.
Therefore, an improvement in the accuracy of the normal judgment range can be expected.

Also, since the power supply frequency can be independently set when the power supply frequency is 60 Hz / 50 Hz, an accurate normal judgment range in consideration of the regional difference in the power supply frequency can be secured.

Further, since a unique setting can be made when the power supply voltage is 100 V / 200 V, an accurate normal judgment range can be secured even for heaters for 100 V and 200 V.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an air conditioner equipped with a heater according to first to fourth embodiments of the present invention.

FIG. 2 is an electronic circuit diagram of a control unit 1 according to the first to fourth embodiments.

FIG. 3 is a correlation diagram showing the relationship between the heater current and the analog input port voltage of the CPU according to the first embodiment.

FIG. 4 is a timing chart showing control contents of the first embodiment.

FIG. 5 is a timing chart showing control contents of a second embodiment.

FIG. 6 is a correlation diagram showing a relationship between a heater current, an analog input port voltage of a CPU, and a power supply frequency according to a third embodiment.

FIG. 7 is a timing chart showing control contents of the third embodiment.

FIG. 8 shows a power supply voltage of the fourth embodiment for 100V and 200V.
Explanatory diagram of heater resistance value and heater current value

FIG. 9 is a timing chart showing control contents of the fourth embodiment.

FIG. 10 is a timing chart showing control contents in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control device 2 Current transformer 3 Heater 4 Heater relay 11 CPU 14 Power supply frequency detection circuit 15 Power supply voltage detection circuit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F24F 11/02 102

Claims (4)

(57) [Claims] An indoor unit of an air conditioner includes a heater, a current transformer for detecting a current of the heater, ON / OFF means for the heater, and a control unit for inputting a converted voltage of the current transformer. And a timer unit, a first setting unit, and a second setting unit are provided in the control unit for judging a heater current.
The setting means is set at a higher setting than the first setting means. When the heater is ON, if the heater current is within the range between the first setting means and the second setting means, the heater is kept ON and the heater current is set to the first setting means. And a heater current detection control device of the air conditioner for turning off the heater after a predetermined time if the heater is out of the range of the second setting means. 2. A timer means, a first setting means, and a second setting means are provided for judging a heater current in the control section.
The second setting means is set at a higher setting than the first setting means, and when the heater is turned on, the setting of the first setting means and the setting of the second setting means is performed after a certain time from when the heater current reaches the first setting means or more. The heater current detection control device for an air conditioner according to claim 1, wherein the value is shifted downward. 3. A power supply frequency detecting means, a first setting means, a second setting means, and
Third setting means and fourth setting means are provided, and the second setting means has a higher setting than the first setting means, and the fourth setting means has a lower setting than the second setting means, and has a third setting means. The means is configured with a lower setting than the first setting means, and the power supply frequency is 60H
2. The heater of the air conditioner according to claim 1, wherein only the first setting means and the second setting means are valid at the time of z, and only the third setting means and the fourth setting means are valid at the power frequency of 50 Hz. Current detection control device. 4. A power supply voltage detecting means, a first setting means, a second setting means, a fifth setting means, a sixth setting means, and a second setting means for judging a heater current in the control section. Is higher than the first setting means, the sixth setting means is lower than the second setting means, and the fifth setting means is the first setting means.
When the power supply voltage is 100 V, only the first setting means and the second setting means are enabled, and when the power supply voltage is 200 V, only the fifth setting means and the sixth setting means are configured. The heater current detection control device for an air conditioner according to claim 1, which is effective.