JP2002270336A - Control device of ptc heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to suppress a rush current including the peak value by operating connection wire of a PTC heater in a prescribed time when supplying current or the PTC heater, aim at improving utilization rate of a breaker, and aim at reduction of the rated current of an electric circuit. SOLUTION: Current supplying is carried out by connecting the wire so that the first PTC heater 1 and the second PTC heater 2 are serially connected at the time of supply current start of the PTC heater, and supplying the current while switching the connection wire of the first PTC heater 1 and the second PTC heater 2 to the parallel connection from the series connection, the rush current of the PTC heater is reduced after the PTC heater temperature rises and the resistance value of the PTC heater becomes larger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling a PTC heater, and more particularly to a PTC heater control device having a function of reducing an inrush current when the power is turned on.

[0002]

2. Description of the Related Art A PTC heater has a sudden change in resistance temperature called the Curie point, and takes a minimum value of the resistance at the Curie point. The Curie point is generally present between the operating point when the PTC is not energized (room temperature) and the operating point when the PTC heater is energized, and the Curie point between the room temperature and the operating point temperature when energized is the minimum point of the so-called resistance value. Pass through. Therefore, a large current (so-called inrush current) flows when the PTC heater is energized. When the temperature of the PTC heater increases due to energization, the resistance value increases, so that the current becomes about 1/2 to 1/4 of the inrush current during steady operation. If the inrush current is large, there is a possibility that the electric circuit and the wiring may burn. In addition, since an existing breaker having a small capacity is cut off, an electric circuit must be designed according to the load at that moment.
In other words, to cope with the inrush current that increases instantaneously,
There will be a need to change control methods, electrical circuits, and breakers.

As a means for solving the above problem, a method of providing a delay time when a plurality of PTC heaters are energized and preventing a rush current of the PTC heaters from flowing at one time as shown in FIGS. There is. However, PTC
In reality, depending on the capacity of the heater, the existing breaker capacity often reaches the limit. on the other hand,
As described in Japanese Patent Application Laid-Open No. 2000-138091, there is an apparatus in which control is performed by intermittently turning on only a part of the AC cycle. Although this is effective in reducing the breaker capacity, the peak value of the rush current cannot be reduced, so it is necessary to make the electric circuit that can tolerate the peak value of the rush current. The problem that the mounting surface becomes large has not been solved yet.

[0004]

When a breaker having a large rated current corresponding to the current value of the inrush current is used, the inrush current having a large current value flows during several to several tens of seconds when the PTC heater is turned on. And then １ ／ of the inrush current
Since the current value is reduced to about 1/4, only about 1/2 to 1/4 of the rated power of the breaker is used during the steady operation, and there is a problem that the utilization rate of the breaker is low and wasteful. In addition, when the power is turned on intermittently only for a part of the AC cycle, the peak value of the inrush current cannot be reduced, although it is effective in reducing the capacity of the breaker rating. It was necessary to make the circuit configuration possible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the breaker utilization by suppressing the rush current including the peak value at the start of energizing the PTC heater. Another object of the present invention is to provide a PTC heater control device that realizes a reduction in the current rating of an electric circuit.

[0006]

In order to achieve the above object, a first aspect of the present invention is a commercial power supply, first and second PTC heaters connected to the commercial power supply, and a connection for switching the connection of the PTC heater. In a PTC heater control device including first, second and third switching means and control means for controlling the switching means, a first PT
A series circuit connected in series in the order of the C heater, the first switching means, and the second PTC heater is connected, and a serial connection point between the commercial power supply and the first PTC heater is connected to the first circuit.
A second switching means is connected between a serial connection point of the second PTC heater and a serial connection point of the second PTC heater, and a serial connection point of the commercial power supply and the second PTC heater is connected to the first PTC heater.
A third switch between the series connection point of the heater and the first switching means;
Is connected, so that when the power supply to the PTC heater is started, the first switching means is connected.
By connecting the PTC heater and the second PTC heater in series, the combined resistance value can be increased, so that the inrush current can be greatly reduced. Further, at the time of steady operation, by switching the first PTC heater and the second PTC heater to the parallel connection, it is possible to obtain the conventional heater performance.

A second aspect of the present invention is a commercial power supply, first and second PTC heaters connected to the commercial power supply, and first, second, third, and fourth switching means for switching connection of the PTC heater. And a control means for controlling the switching means, wherein a first switching means, a first PTC heater and a second PTC heater are provided at both ends of the commercial power supply.
And a series circuit connected in series in the order of the PTC heater and the second switching means, and the commercial power supply and the first
A third switching means is connected between a series connection point of the switching means and a series connection point of the first PTC heater and the second PTC heater, and a series connection point of the commercial power supply and the second switching means. And a fourth switching means is connected between a series connection point of the first switching means and the first PTC heater, so that when the PTC heater is energized, the first switching means is switched by the switching means. By connecting the and the second PTC heater in series, the combined resistance value can be increased, so that the inrush current can be greatly reduced. Also, during normal operation, the first PTC
By switching the heater and the second PTC heater in parallel connection, it is possible to obtain the same heater performance as before.

Preferably, the control means includes a time measuring means for measuring time, and the PT measured by the time measuring means.
When the time after the start of energization of the C heater becomes equal to or more than a predetermined value, the connection of the first and second PTC heaters to the commercial power source is turned on by the first switching means, and The inrush current is characterized by switching from a series connection in which the third switching means is turned off to a parallel connection in which the first switching means is turned off and the second and third switching means are turned on. Can be greatly reduced, and switching from series connection to parallel connection can be performed smoothly.

According to a fourth aspect of the present invention, the control means includes time measuring means for measuring time, and current detecting means for detecting a current flowing through the PTC heater, wherein the PT measured by the time measuring means is provided.
When the time after the start of energization of the C heater is equal to or more than a predetermined value and the current detected by the current detection means is equal to or less than a predetermined value, the connection of the first and second PTC heaters to the commercial power supply is changed. From the series connection in which the first switching means is turned on and the second and third switching means are turned off, the first switching means is turned off, and the second and third switching means are turned off. The control means switches to the parallel connection in which the PTC heater is turned on. The control means comprises: a time measuring means for measuring a time; and a current detecting means for detecting a current flowing through the PTC heater.
When the time after the start of energization of the C heater is equal to or greater than a predetermined value and the current detected by the current detecting means is equal to or less than a predetermined value, the connection between the first PTC heater and the second PTC heater is established. Is switched from series connection to parallel connection, so that inrush current can be greatly reduced, and switching from series connection to parallel connection can be performed smoothly. Since the connection is switched by directly detecting the current, there is no need to take a margin for variation due to the ambient environment or the variation in voltage of the AC power supply, etc., thus eliminating the time loss of switching from series connection to parallel connection. It becomes possible.

[0010] The control means may be arranged so that the control means comprises a PTC.
A temperature detecting means for detecting a temperature of the heater, and when the temperature detected by the temperature detecting means becomes equal to or higher than a predetermined value, a connection between the first PTC heater and the second PTC heater is connected in series and connected in parallel. Since the connection is switched, the inrush current can be greatly reduced, and the switching from the series connection to the parallel connection can be smoothly performed. Since the connection is switched by directly detecting the temperature of the PTC heater, there is no need to take a margin for variation due to the ambient environment or the variation in voltage of the AC power supply, so that the time loss of switching from series connection to parallel connection is reduced. It can be eliminated.

According to a sixth aspect of the present invention, the control means includes the PTC
When the temperature of the temperature detecting means is equal to or higher than a predetermined value when the heater is energized, the first and second PTs with respect to the commercial power supply are output.
Since the connection of the C heater is conducted in a parallel connection in which the first switching means is turned off and the second and third switching means are turned on, the connection in the series connection which is not necessary is performed. It is possible to prevent energization and immediately perform a steady operation in parallel connection.

Preferably, the control means includes time counting means for measuring a time, and the PT measured by the time counting means.
When the time after the start of energization of the C heater becomes equal to or more than a predetermined value, the connection of the first and second PTC heaters to the commercial power source is turned on by the first and second switching means, and Switching from series connection with the third and fourth switching means turned off to parallel connection with the first switching means turned off and the second, third and fourth switching means turned on. Can be greatly reduced, and switching from series connection to parallel connection can be performed smoothly.

Preferably, the control means includes a time measuring means for measuring time, and a current detecting means for detecting a current flowing through the PTC heater, wherein the time after the start of energizing the PTC heater measured by the time measuring means is provided. When the current is equal to or more than a predetermined value and the current detected by the current detecting means becomes equal to or less than a predetermined value, the first and second PTs with respect to the commercial power supply are
Connecting the C heater from a series connection in which the first and second switching means are turned on and the third and fourth switching means are turned off, and the first switching means is turned off;
In addition, it is possible to greatly reduce the inrush current characterized by switching to the parallel connection in which the second, third, and fourth switching means are turned on, and to smoothly switch from the series connection to the parallel connection. Can be done. Since the connection is switched by directly detecting the current, there is no need to take a margin for variation due to the ambient environment or the variation in voltage of the AC power supply, etc., thus eliminating the time loss of switching from series connection to parallel connection. It becomes possible.

According to a ninth aspect of the present invention, the control means includes the PTC
Temperature detecting means for detecting the temperature of the heater, and when the temperature detected by the temperature detecting means becomes a predetermined value or more, the connection of the first and second PTC heaters to the commercial power supply From the serial connection in which the first and second switching means are turned on and the third and fourth switching means are turned off, the first switching means is turned off and the second, third and fourth switching means are turned off. Since the switching is switched to the parallel connection in which the switching means is turned on, the rush current can be greatly reduced, and the switching from the series connection to the parallel connection can be smoothly performed. PT
Since the connection is switched by directly detecting the temperature of the C heater, there is no need to take a margin for variations due to the ambient environment or variations in the voltage of the AC power supply, so the time loss of switching from series connection to parallel connection is reduced. It can be eliminated.

In another preferred construction, the control means controls the PT.
When the temperature of the temperature detecting means is equal to or higher than a predetermined value when the C heater is energized, the first and second P with respect to the commercial power supply are
The connection of the TC heater is changed from a series connection in which the first and second switching means are turned on and the third and fourth switching means are turned off, the first switching means is turned off, and the TC heater is turned off. Since the switching is switched to the parallel connection in which the second, third, and fourth switching means are turned on, it is possible to prevent unnecessary energization in the series connection and immediately perform a steady operation operation in the parallel connection. It becomes possible.

In a preferred embodiment, the control means includes a commercial voltage detecting means, and the commercial voltage detecting means switches the switching means in synchronization with a signal indicating detection of a zero voltage of the commercial power supply. Because of the feature, since a large current is not turned on / off, generation of electromagnetic wave noise can be suppressed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a PTC heater control device according to an embodiment of the present invention are shown in FIGS.
The description will be made based on 5 to 17. 1 and 2 are configuration diagrams of a PTC heater control device, FIG. 3 is a block configuration diagram of a main part of the PTC heater control device, FIGS. 4 and 5 are schematic external views of the PTC heater, and FIG. 7 and 9 are graphs showing an outline of a correspondence relationship between a resistance value and a temperature, FIGS. 7 and 9 are diagrams showing an energizing operation to a PTC heater, FIGS. 8 and 10 are time charts showing an energizing operation to a PTC heater, and FIG. FIGS. 15 to 17 are flowcharts showing an example of a current waveform when the PTC heater is energized, and FIGS. 15 to 17 illustrate an operation when the PTC heater is energized.

For comparison with the PTC heater control device according to the embodiment of the present invention, FIG. 11 is a diagram showing the operation of energizing the PTC heater in the conventional PTC heater control device.
FIG. 12 is a time chart showing the energizing operation to the TC heater.
It was shown to.

First, as the PTC heater of this embodiment, 1
This will be described with reference to FIGS. 4 and 6 taking the element type as an example. PT
The C heater is formed by the aluminum fin units 22 and 23 and the PTC element 21 interposed therebetween. FIG.
As shown in (1), in the PTC heater, the resistance-temperature characteristic generally changes abruptly near the Curie point Tc. In a temperature range lower than the Curie point, the resistance decreases as the temperature increases. In a temperature range higher than the Curie point, the resistance increases as the temperature increases. In this embodiment, the PTC heater is used in a region where the resistance increases as the temperature increases. In this embodiment, a PTC heater having a Curie point of about 180 ° C. is used, and the maximum surface temperature of the PTC heater during steady operation is about 2 ° C.
The temperature is set to 00 ° C. (T1).

When a one-element type PTC heater is used, the configuration of the PTC heater control device includes a first PTC heater 1, a second PTC heater 2, a first relay 3, and a second relay 4. , A third relay 5, and a control circuit 7, and the connection is as shown in FIG. First PTC heater 1
And when the second PTC heater 2 is energized in series connection,
Only the first relay 3 is turned on. Also, the first PTC
When the heater 1 and the second PTC heater 2 are energized in parallel connection, two of the second relay 4 and the third relay 5 are turned on.

Next, a PTC heater of this embodiment will be described with reference to FIGS. 2 and 6 by taking a two-element integrated type as an example. P
The TC heater includes a first PTC heater including aluminum fin units 22 and 23 and a PTC element 21 sandwiched therebetween, and a second PTC heater including aluminum fin units 25 and 26 and a PTC element 24 sandwiched therebetween. Are formed integrally with the split pins 27 and 28. Similarly to the one-element type, the resistance-temperature characteristics of the two-element integrated type suddenly change around the Curie point Tc as shown in FIG.
In a temperature range lower than the Curie point, the resistance decreases as the temperature increases. In a temperature range higher than the Curie point, the resistance increases as the temperature increases. In this embodiment, the PTC heater is used in a region where the resistance increases as the temperature increases. In addition,
In this embodiment, a PTC heater having a Curie point of about 180 ° C. is used, and the maximum surface temperature of the PTC heater during a steady operation is about 200 ° C. (T1).

When a two-element integrated type PTC heater is used, the configuration of the PTC heater control device includes a first PTC heater 1, a second PTC heater 2, and a first relay 8
, The second relay 9, the third relay 10, the fourth relay 11, and the control circuit 7, and the connection is as shown in FIG. First PTC heater 1 and second PTC heater 2
Are connected in series, the first relay 8 and the second relay 9 are turned on. When the first PTC heater 1 and the second PTC heater 2 are energized in a parallel connection, three of the second relay 9, the third relay 10, and the fourth relay 11 are turned on.

As shown in FIG. 3, the PTC control device includes a power supply circuit 31, a CPU 32 having a built-in timer, a relay drive circuit 33, a relay circuit 34, a PTC heater 35, a temperature sensor 36, It comprises a sensor 37 and a voltage detection circuit 38.

The power supply circuit 31 is connected from the commercial power supply 6 to the CPU 3.
2 is provided with a function of generating a required voltage (for example, 5 V DC). The power supply circuit 31 also has a function of supplying the commercial voltage as it is.

The relay drive circuit 33 amplifies the relay drive signal from the CPU 32 to a signal level required for turning on / off the relay. Relay drive circuit 3
3 and a relay constituting the relay circuit 34 is turned on and off, and the commercial power supply 6 supplied from the power supply circuit 31 is supplied to the PTC heater 1 composed of the first PTC heater 1 and the second PTC heater 2. The heater 35 is turned on / off.

The relay circuit 34 has a function of switching the connection between the first PTC heater and the second PTC heater to a series connection or a parallel connection as shown in FIG.

The CPU 32 has a program in which a timer and a control operation are defined, and realizes various control functions by executing the program. For example, the CPU 32 has a function of instructing the relay drive circuit 33 to turn on / off a commercial power supply. CP
U32 controls on / off of the voltage based on the detection signal of the commercial voltage detection circuit 38. In the present embodiment, a relay is described as an example of the switching unit for turning on / off the commercial power, but the type of the switching unit is not particularly limited.

The temperature sensor 36 is for detecting the temperature of the PTC heater 35. The type, specific configuration, and the like of the sensor are not particularly limited.

The current sensor 37 is for detecting a current flowing through the PTC heater 35. In the present embodiment, an electromagnetic probe type sensor is described as an example, but the type of the current detecting means is not particularly limited.

When the commercial voltage becomes zero, the commercial power supply pressure detecting circuit 38 outputs a zero-cross signal indicating this to C
It has a function of outputting to the PU 32.

A first embodiment of the operation of the PTC heater control device having the above configuration will be described with reference to FIG. When the operation is started in a state where the control device is energized (step 1) (step 2), the CPU 32 starts a timer (step 3). In step 4, the relay drive circuit 33
Through the relay circuit 34, the first PTC heater and the second PTC heater constituting the PTC heater 35 are connected so that they are connected in series, and the relay circuit 34 starts energization. When connected in series, the combined resistance of the PTC heaters 35 becomes larger than in the case of parallel connection, so that the current is limited. The timer read in step 5 is changed to step 6
Is compared with a preset time (10 seconds in this embodiment), and when the timer becomes 10 seconds or more, the PTC heater 35
The connection between the first PTC heater and the second PTC heater is switched from a series connection to a parallel connection, and power is supplied (step 7).

A second embodiment of the operation of the PTC heater control device will be described with reference to FIG. When the operation is started (step 9) with the control device energized (step 8), the CPU 32 detects the PT detected by the temperature sensor 36.
The temperature of the C heater 35 is compared with a preset temperature (190 ° C. in the present embodiment) (step 10), and the detected temperature becomes 1
When the temperature is lower than 90 ° C., through the relay driving circuit 33, the relay circuit 34 makes the first PTC constituting the PTC heater 35.
The TC heater and the second PTC heater are connected so as to be connected in series, and energization is started (step 11). When connected in series, the PTC
Since the combined resistance of the heater 35 increases, the current is limited. When the detected temperature becomes equal to or higher than 190 ° C. in Step 10, the relay circuit 34
A first PTC heater constituting the PTC heater 35 and a second PTC heater
The connection of the PTC heater is switched from the serial connection to the parallel connection to energize (step 12). According to the present embodiment, when the power supply to the PTC heater 35 is stopped once and then the power supply is again performed, the PTC heater 35 detected by the temperature sensor 36 is used.
When the temperature is 190 ° C. or higher, the current is not supplied in the above-described series connection but is supplied in the parallel connection. Therefore, operation with unnecessary DC connection can be prevented. In addition, since the resistance value can be immediately known from the temperature of the PTC heater 35 by the temperature sensor 36, there is no need for a time margin when switching from energization in series connection to energization in parallel connection.

A third embodiment of the operation of the PTC heater control device will be described with reference to FIG. When the operation is started with the control device energized (step 13) (step 14), the CPU 32 starts a timer (step 15). In step 16, through the relay drive circuit 33, the relay circuit 34 connects the first PTC heater and the second PTC heater constituting the PTC heater 35 so that they are connected in series, and starts energization. When connected in series, the PTC heater 35
Current is limited because the combined resistance of The timer read in step 17 is compared with the time preset in step 18 (20 seconds in this embodiment),
When the timer reaches 20 seconds or more, the current value detected by the current detection circuit provided in the power supply circuit 31 is compared with a preset current value (3 A in this embodiment) (Step 19).
When the detected current exceeds 3 A, the relay drive circuit 33
Through the relay circuit 34, the connection of the first PTC heater and the second PTC heater constituting the PTC heater 35 is switched from series connection to parallel connection, and power is supplied (step 20). According to the present embodiment, the direct PTC heater 35
Since the control is performed by directly detecting the current flowing through the power supply, the current can be reliably limited.

The details of the method of switching the connection of the PTC heater will be described with reference to FIGS.

First, details of the method of switching the one-element type PTC heater will be described with reference to FIGS. FIG. 7A shows a state where both the first PTC heater 1 and the second PTC heater 2 are not energized. When the operation is started, the first relay 3 is turned on to enter the series connection energized state shown in FIG. 7B. FIG. 7B shows a state in which the first PTC heater 1 and the second PTC heater 2 are connected in series to the commercial power supply 6, and the current is limited because the combined resistance of the PTC heaters increases. . PT in this state
FIG. 7C in which the first relay is turned off and the second and third relays are turned on when the temperature of the C heater rises and the resistance value exceeds the Curie point (Tc) and becomes large. In a parallel connection state. FIG. 7C shows a state in which the first PTC heater 1 and the second PTC heater 2 are connected in parallel to the AC power supply 6. This state is a steady state. The switching of the relay is performed by a commercial voltage detection circuit.
It is performed at the timing when the detection voltage becomes 0. In the present embodiment, the first relay 3, the second relay 4, and the third relay 5 are all configured as single-pole relays, but the first relay 3 and the second relay 4 are replaced with bipolar relays. Can also be configured. Alternatively, the first relay 3 and the third relay 5 can be configured by bipolar relays.

Next, the switching method of the two-element integrated type PTC heater will be described in detail with reference to FIGS. FIG.
(A) is a state in which both the first PTC heater 1 and the second PTC heater 2 are not energized. When the operation is started, the first relay 8 and the second relay 9 are turned on to be in the series connection energized state shown in FIG. 9B. FIG. 9B shows that the first PTC heater 1 and the second PTC
This is a state in which the heaters 2 are connected in series, and the combined resistance of the PTC heaters increases, so that the current is limited. When the temperature of the PTC heater rises due to the energization in this state and the resistance value exceeds the Curie point (Tc), the first
Is turned off, and the second, third, and fourth relays are turned on to establish the parallel connection state of FIG. 9C. FIG. 9 (c)
Is connected to the commercial power source 6 by the first PTC heater 1 and the second
PTC heaters 2 are connected in parallel. This state is a steady state. The above switching of the relay
This is performed at the timing when the detection voltage becomes 0 in the commercial voltage detection circuit. In the present embodiment, the first to eighth relays 8 to 4
Although all the relays 11 are configured as single-pole relays, the first relay 8 and the third relay 10 may be configured as bipolar relays.

For comparison, an example of a conventional PTC heater connection switching method is shown in FIGS. FIG. 11A shows the first PTC heater 1 and the second PT
Both the C heaters 2 are not energized. When the operation is started, one PTC heater shown in FIG. 11B is energized with the first relay turned on. At a point in time when a predetermined time (for example, 10 seconds) has elapsed since the first PTC heater was turned on, the first relay 12 continues to be on.
The parallel connection state shown in FIG. 11C in which the second relay 13 is turned on is set. By shifting the timing at which the commercial power source 6 is supplied to the first PTC heater 1 and the second PTC heater 2, the rush currents of the two PTC heaters are prevented from flowing simultaneously.

FIG. 13 shows an example of a current waveform when the PTC heater 35 is energized by the above-described PTC heater connection switching method according to the present invention, and energization to the PTC heater 35 is performed by the conventional PTC heater wiring switching method. FIG. 14 shows an example of the current waveform when the operation is performed. In the present invention, the first PTC
Since the heater and the second PTC heater are connected in series and energized, the resistance value is reduced to half of that in the conventional example where only the first PTC heater is energized. Therefore, the inrush current of the present invention is about 1/2 of the inrush current when only the first PTC heater of the conventional example is energized. The temperature of the PTC heater 35 rises and the Curie point (T
Since the connection is switched after exceeding c), parallel connection energization is performed in a region where the resistance value of the PTC heater 35 (both the first PTC heater and the second PTC heater) is large, and a large inrush current does not flow. In this embodiment, FIG.
As shown in FIG. 3, the peak value of the current from the time when the PTC heater 35 was energized to the time when the parallel connection was energized was about 12 A. Note that, in the conventional example shown in FIG.
When the PTC heater was turned on, only the first PTC heater raised the temperature, so the current peak value was 17A.

As described above, at the start of energization of the PTC heater, P
Inrush current can be reduced by connecting TC heaters in series, and there is no need to change the electric circuit (including the current rating of electronic components) and breakers, so the control board and bathroom heater / dryer can be downsized. And the workability can be improved.

[0040]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, a commercial power supply, first and second PTC heaters connected to the commercial power supply, first, second, and third switching means for switching connection of the PTC heater, and the switching means P comprising control means for controlling
In the TC heater control device, a first PTC heater, a first switching means, and a second PTC are provided at both ends of the commercial power supply.
A series circuit connected in series in the order of the heaters is connected,
Second switching means is connected between a series connection point of the commercial power supply and the first PTC heater and a series connection point of the first switching means and the second PTC heater, and the commercial power supply and the second PTC heater are connected to each other. PTC heater series connection point and the first
The third switching means is connected between the series connection point of the PTC heater and the first switching means, so that when the power supply to the PTC heater starts, the switching means switches the first PTC heater and the second PTC heater. Since the combined resistance value can be increased by connecting the PTC heaters in series, the inrush current can be significantly reduced. Further, at the time of steady operation, by switching the first PTC heater and the second PTC heater to the parallel connection, it is possible to obtain the conventional heater performance.

According to a second aspect of the present invention, a commercial power supply, first and second PTC heaters connected to the commercial power supply,
In a PTC heater control device including first, second, third, and fourth switching means for switching connection of a heater, and control means for controlling the switching means, a first switching means is provided at both ends of the commercial power supply. A series circuit connected in series in the order of a first PTC heater, a second PTC heater, and a second switching means is connected, and a series connection point between the commercial power supply and the first switching means is connected to the first switching circuit. A third switching unit is connected between a series connection point of the PTC heater and the second PTC heater, and a series connection point of the commercial power supply and the second switching unit, the first switching unit, and the first switching unit. Since the fourth switching means is connected between the series connection points of the PTC heaters, the first switching means and the second PTC heater are switched by the switching means at the start of energization of the PTC heater. By the data to a series connection, since the combined resistance value can be increased, it is possible to greatly reduce the rush current. Also, during steady operation, the first PT
By switching the C heater and the second PTC heater to parallel connection, it is possible to obtain the same heater performance as before.

According to a third aspect of the present invention, the control means includes a time measuring means for measuring a time, and the P
When the time after the start of energization of the TC heater becomes equal to or more than a predetermined value, the connection of the first and second PTC heaters to the commercial power source is turned on by the first switching means, and The inrush current is characterized by switching from a series connection in which the third switching means is turned off to a parallel connection in which the first switching means is turned off and the second and third switching means are turned on. Can be greatly reduced, and switching from series connection to parallel connection can be performed smoothly.

According to a fourth aspect of the present invention, the control means includes time measuring means for measuring time, and current detecting means for detecting a current flowing through the PTC heater.
When the time after the start of energization of the TC heater is equal to or more than a predetermined value and the current detected by the current detecting means is equal to or less than a predetermined value, the first and second PTCs with respect to the commercial power supply are
Turning on the first switching means to connect the heater;
And switching from series connection in which the second and third switching means are turned off to parallel connection in which the first switching means is turned off and the second and third switching means are turned on. The control means includes time-measuring means for measuring time, and current detecting means for detecting a current flowing through the PTC heater, wherein the P
When the time after the start of energization of the TC heater is equal to or more than a predetermined value and the current detected by the current detection means is equal to or less than a predetermined value, the first PTC heater and the second PTC
Since the connection of the heater is switched from the series connection to the parallel connection, the inrush current can be greatly reduced, and the switching from the series connection to the parallel connection can be smoothly performed. Since the connection is switched by directly detecting the current, there is no need to take a margin for variation due to the ambient environment or the variation in voltage of the AC power supply, etc., thus eliminating the time loss of switching from series connection to parallel connection. It becomes possible.

According to a fifth aspect of the present invention, the control means includes the PT
Temperature detecting means for detecting the temperature of the C heater, and when the temperature detected by the temperature detecting means becomes equal to or higher than a predetermined value, the connection between the first PTC heater and the second PTC heater is connected in series. Since switching to parallel connection is characterized, inrush current can be greatly reduced, and switching from series connection to parallel connection can be performed smoothly. Since the connection is switched by directly detecting the temperature of the PTC heater, there is no need to take a margin for variation due to the ambient environment or the variation in voltage of the AC power supply, so that the time loss of switching from series connection to parallel connection is reduced. It can be eliminated.

According to a sixth aspect of the present invention, the control means includes:
When the temperature of the temperature detecting means is equal to or higher than a predetermined value when the C heater is energized, the first and second P with respect to the commercial power supply are
The connection of the TC heater is carried out in a parallel connection in which the first switching means is turned off and the second and third switching means are turned on. It is possible to prevent energization and immediately perform a steady operation in parallel connection.

According to a seventh aspect of the present invention, the control means includes time counting means for counting time, and the P
When the time after the start of energization of the TC heater becomes equal to or longer than a predetermined value, the connection of the first and second PTC heaters to the commercial power source is turned on by the first and second switching means, and Switching from series connection with the third and fourth switching means turned off to parallel connection with the first switching means turned off and the second, third and fourth switching means turned on. Can be greatly reduced, and switching from series connection to parallel connection can be performed smoothly.

According to another aspect of the present invention, the control means includes a time measuring means for measuring time, and a current detecting means for detecting a current flowing through the PTC heater, wherein the time after the start of energizing the PTC heater is measured by the time measuring means. When the current is equal to or more than a predetermined value and the current detected by the current detection means is equal to or less than a predetermined value, the first and second P
The connection of the TC heater is changed from a series connection in which the first and second switching means are turned on and the third and fourth switching means are turned off, the first switching means is turned off, and the TC heater is turned off. Switching in parallel with the second, third, and fourth switching means turned on can greatly reduce inrush current, and smoothly switch from series connection to parallel connection. Can be. Since the connection is switched by directly detecting the current, there is no need to take a margin for variation due to the ambient environment or the variation in voltage of the AC power supply, etc., thus eliminating the time loss of switching from series connection to parallel connection. It becomes possible.

According to a ninth aspect of the present invention, the control means includes the PT
A temperature detecting means for detecting a temperature of the C heater, and when the temperature detected by the temperature detecting means becomes a predetermined value or more, the connection of the first and second PTC heaters to the commercial power source is changed to From the serial connection in which the first and second switching means are turned on and the third and fourth switching means are turned off, the first switching means is turned off and the second, third and fourth switching means are turned off. Is switched to the parallel connection in which the switching means is turned on, so that the inrush current can be greatly reduced, and the switching from the series connection to the parallel connection can be smoothly performed. PT
Since the connection is switched by directly detecting the temperature of the C heater, there is no need to take a margin for variations due to the ambient environment or variations in the voltage of the AC power supply, so the time loss of switching from series connection to parallel connection is reduced. It can be eliminated.

According to a tenth aspect of the present invention, the control means controls the P
When the temperature of the temperature detecting means is equal to or higher than a predetermined value when the TC heater is energized, the connection of the first and second PTC heaters to the commercial power supply is turned on by the first and second switching means, and Switching from series connection with the third and fourth switching means turned off to parallel connection with the first switching means turned off and the second, third and fourth switching means turned on. Therefore, it is possible to prevent power supply in unnecessary series connection, and to immediately perform steady operation in parallel connection.

According to an eleventh aspect of the present invention, the control means includes a commercial voltage detecting means, and the commercial voltage detecting means switches the switching means in synchronization with a signal indicating detection of a zero voltage of the commercial power supply. Because of the feature, since a large current is not turned on / off, generation of electromagnetic wave noise can be suppressed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a PTC heater control device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a PTC heater control device according to an embodiment of the present invention.

FIG. 3 is a block diagram of a main part of the PTC heater control device according to the embodiment of the present invention.

FIG. 4 is a schematic external view of a PTC heater provided in the PTC heater control device according to the embodiment of the present invention.

FIG. 5 is a schematic external view of a PTC heater provided in the PTC heater control device according to the embodiment of the present invention.

FIG. 6 is a graph showing an outline of a correspondence relationship between a resistance value and a temperature of a PTC heater provided in the PTC heater control device according to the embodiment of the present invention.

FIG. 7 is a diagram showing a power supply operation to the PTC heater of the PTC heater control device according to the embodiment of the present invention.

FIG. 8 is a time chart showing the operation of the PTC heater control device according to the embodiment of the present invention when the PTC heater is energized.

FIG. 9 is a diagram showing a power supply operation to the PTC heater of the PTC heater control device according to the embodiment of the present invention.

FIG. 10 is a time chart showing an operation when power is supplied to the PTC heater in the PTC heater control device according to the embodiment of the present invention.

FIG. 11 is a diagram showing a power supply operation to a PTC heater of a conventional PTC heater control device.

FIG. 12 is a time chart showing an operation of a conventional PTC heater control device when energizing a PTC heater.

FIG. 13 is a current waveform when the PTC heater is energized in the PTC heater control device according to the embodiment of the present invention.

FIG. 14 is a current waveform when a PTC heater of a conventional PTC heater control device is energized.

FIG. 15 is a flowchart illustrating an example for explaining an operation of the PTC heater control device according to the embodiment of the present invention when the PTC heater is energized.

FIG. 16 is a flowchart illustrating an example for explaining an operation of the PTC heater control device according to the embodiment of the present invention when the PTC heater is energized.

FIG. 17 is a flowchart illustrating an example for explaining an operation of the PTC heater control device according to the embodiment of the present invention when the PTC heater is energized.

[Explanation of symbols]

1: first PTC heater, 2: second PTC heater, 3
... first relay, 4 ... second relay, 5 ... third relay, 6 ... commercial power supply, 7 ... control means, 8 ... first relay, 9
... second relay, 10 ... third relay, 11 ... fourth relay, 21 ... PTC element, 22 ... aluminum fin unit, 23 ... aluminum fin unit, 24 ... PTC element,
25 ... aluminum fin unit, 26 ... aluminum fin unit, 27 ... split pin, 28 ... split pin, 31 ... power supply circuit,
32 CPU, 33 relay drive circuit, 34 relay circuit, 35 PTC heater, 36 temperature sensor, 37 current sensor, 38 commercial voltage detection circuit

Claims (11)

[Claims] 1. A commercial power supply, first and second PTC heaters connected to the commercial power supply, first, second, and third switching means for switching the connection of the PTC heater, and the switching means. And a control means for controlling the PTC heater.
A series circuit connected in series in the order of the TC heater, the first switching means, and the second PTC heater is connected, and a series connection point of the commercial power supply and the first PTC heater, the first switching means, Second switching means is connected between the series connection points of the second PTC heater, and the series connection point of the commercial power supply and the second PTC heater is connected to the first PTC.
A third switching means connected between a series connection point of the C heater and the first switching means.
TC heater control device. 2. A commercial power supply, first and second PTC heaters connected to the commercial power supply, and first, second, third, and fourth switching means for switching connection of the PTC heater, P comprising control means for controlling the switching means
In the TC heater control device, a first switching means, a first PTC heater, and a second PTC are provided at both ends of the commercial power supply.
A series circuit connected in series in the order of the heater and the second switching unit is connected, and a series connection point of the commercial power supply and the first switching unit, the first PTC heater, and the second PTC heater. A third switching means is connected between the series connection points, and a series connection point of the commercial power supply and the second switching means, the first switching means, and the first PT
A PTC heater control device, wherein a fourth switching means is connected between the series connection points of the C heaters. 3. The PTC heater control device according to claim 1, wherein said control means includes a time measuring means for measuring a time, and a time after said PTC heater energization started measured by said time measuring means is a predetermined value or more. At this point, the connection of the first and second PTC heaters to the commercial power supply is turned on by the first switching means, and the second and third PTC heaters are turned on.
A PTC heater control device characterized by switching from a series connection in which the switching means is turned off to a parallel connection in which the first switching means is turned off and the second and third switching means are turned on. 4. The PTC heater control device according to claim 1, wherein said control means includes a time measuring means for measuring a time, and a current detecting means for detecting a current flowing through said PTC heater, and the time is measured by said time measuring means. When the time after the start of energization of the PTC heater is equal to or more than a predetermined value and the current detected by the current detection means is equal to or less than a predetermined value, connection of the first and second PTC heaters to the commercial power supply is performed. From the series connection in which the first switching means is turned on and the second and third switching means are turned off, the first switching means is turned off, and the second and third switching means are turned off.
A PTC heater control device, which switches to a parallel connection in which the switching means is turned on. 5. The PTC heater control device according to claim 1, wherein the control means includes a temperature detection means for detecting a temperature of the PTC heater, and the temperature detected by the temperature detection means is equal to or higher than a predetermined value. At the time, the connection of the first and second PTC heaters to the commercial power source is changed from the series connection in which the first switching unit is turned on and the second and third switching units are turned off. A PTC heater control device, wherein the first switching means is turned off and the second and third switching means are turned on to switch to parallel connection. 6. The PTC heater control device according to claim 5, wherein said control means controls said first and second power supplies to said commercial power supply when the temperature of said temperature detection means is equal to or higher than a predetermined value when said PTC heater is energized. A PTC heater control device, wherein the connection of the PTC heater is energized in a parallel connection in which the first switching means is turned off and the second and third switching means are turned on. 7. The PTC heater control device according to claim 2, wherein the control means includes a time measuring means for measuring a time, and the time after the PTC heater energization time measured by the time measuring means is equal to or more than a predetermined value. At this point, the connection of the first and second PTC heaters to the commercial power source is connected in series with the first and second switching means turned on and the third and fourth switching means turned off. A PTC heater control device, wherein the connection is switched from a connection to a parallel connection in which the first switching means is turned off and the second, third, and fourth switching means are turned on. 8. The PTC heater control device according to claim 2, wherein the control means includes a time measuring means for measuring time, and a current detecting means for detecting a current flowing through the PTC heater, and the time is measured by the time measuring means. When the time after the start of energization of the PTC heater is equal to or more than a predetermined value and the current detected by the current detection means is equal to or less than a predetermined value, connection of the first and second PTC heaters to the commercial power supply is performed. From the serial connection in which the first and second switching means are turned on and the third and fourth switching means are turned off, the first switching means is turned off, and the second and third switching means are turned off. A PTC heater control device for switching to a parallel connection in which the fourth switching means is turned on. 9. The PTC heater control device according to claim 2, wherein the control means includes a temperature detection means for detecting a temperature of the PTC heater, and the temperature detected by the temperature detection means is equal to or higher than a predetermined value. The connection of the first and second PTC heaters to the commercial power supply, turning on the first and second switching means, and
PTC switching from series connection in which the fourth switching means is turned off to parallel connection in which the first switching means is turned off and the second, third, and fourth switching means are turned on. Heater control device. 10. The PTC heater control device according to claim 9, wherein said control means controls said first and second power supplies to said commercial power supply when the temperature of said temperature detection means is equal to or higher than a predetermined value when said PTC heater is energized. The connection of the PTC heater from the series connection in which the first and second switching means are turned on and the third and fourth switching means are turned off, the first switching means is turned off, and A PTC heater control device characterized by switching to a parallel connection in which second, third, and fourth switching means are turned on. 11. The PTC heater control device according to claim 1, wherein the control unit includes a commercial voltage detecting unit, and the commercial voltage detecting unit synchronizes with a signal that detects a zero voltage of the commercial power supply. And a PTC heater control device for switching the switching means.