DE10327342A1 - Electric heating system - Google Patents

Abstract

It is an electric heating system with an electrically insulating backing (1), an electrically conductive heating layer disposed thereon (2), at least two spaced from each other on the heating layer (2) arranged and standing with this in electrically conductive contact Electrodes (3, 4) and a power source electrically connected to these, wherein the power source is a switching power supply (7) having a power control unit is, from which of the heating layer (2) flowing through current (1a) is controlled.

Description

The The invention relates to an electric heating system with an electric insulating carrier layer, an arranged on this, electrically conductive heating layer, at least two spaced from each other on the heating layer and with these electrodes in conductive contact and a with this electrically connected power source.

From the DE 198 57 493 A1 For example, an electric heater assembly with an electrically conductive surface coating is known, which is provided with power supply conductors which are in electrical contact with the surface coating and are connected to a power supply source. The supply voltage is 42 volts to 220/230 volts or 380 volts.

Furthermore, from the DE 197 26 689 A1 an electric heating system with a film carrier is known, which is coated with an electric heating layer to heat rooms in apartments. The electrical heating layer is contacted with power supply electrodes, which are wired via connecting leads to a power supply device. Furthermore, a temperature controller may be provided for controlling the surface temperature of the heating layer.

task The invention is an electric heating system of the above to create said type whose heat output adjusted as low as possible can be.

These The object is achieved by a electric heating system having the features of claim 1 and by the use of a provided with a power control unit Switching power supply as a power source for an electric heater according to claim 19 solved. Preferred developments are in the subclaims claimed.

The electrical according to the invention Heating system has an electrically insulating carrier layer, an arranged on this, electrically conductive heating layer, at least two spaced apart on the heating layer and arranged with this in electrically conductive contact standing electrodes and one with this electrically connected power source, wherein the power source a switching power supply with a current control unit, of which the heating layer flowing through Power is controlled.

To the Achieving a certain heating power can be the heating layer flowing through Power adjusted by the power control unit accordingly. The use of a switching power supply has the great advantage that this very low-loss works and especially against a power supply with a linear regulator gives off less energy in the form of heat. The heating power let yourself Therefore, adjust with low losses, so that the inventive electric Heating system is energy-saving controlled. It is preferred the power control unit connected to the switch of the switching power supply and formed such that from this for controlling the heating layer flowing through Current the duty cycle the switch is controlled.

The Switching Power Supply can with a secondary clocked switching power supply be provided. Preferably, the switching power supply but a primary clocked switching power supply, so that it is possible to reduce the losses of Switching power supply even further, because in a primary switched mode power supply also the losses of its power transformer can be reduced. One primary Clocked switching power supply can be on the primary side of the power transformer with frequencies of e.g. 20 kHz to 200 kHz work in comparison to the usual in the general supply network frequency of z. B. 50 Hz are very high. These high frequencies are preferred with generates a vibration generator, the corresponding AC voltages can deliver. Because the required number of turns for the power transformer decrease with increasing frequency, the number of turns of the Mains transformer can be reduced, not only to reduce the Losses leads, but also the possibility opened, the spatial Expansion of the mains transformer. The vibrator is integrated in the power control unit or separately from this trained, with the frequency or the frequencies of this controlled AC voltage or AC voltages can be adjustable or can. In a particularly simple embodiment of the invention the power control unit essentially from the vibration generator.

If only a very small heating current is required, then the duty ratio of the switch can be very small, which can lead to an undesirably large ripple of this current, in particular in a rectification of the current flowing through the heating layer at the output of the switching power supply. For this reason, the current control unit connected to the switch of the switched-mode power supply is preferably designed such that the duty cycle of the switch as well as the height of the primary switching of the switched-mode power supply on the primary winding of the power transformer of the switch circuit power supply are present for controlling the current flowing through the heating layer the voltage is controlled. Thus, to reduce the current flowing through the heating layer, for example, the voltage applied to the primary winding can be reduced without having to reduce the duty cycle. Thus, the ripple of the heating layer flowing through and in particular rectified current can be reduced.

to Control of the height the at the primary winding applied voltage, the power control unit preferably has a Switching regulator on, whose output voltage on the duty cycle of the switch the switching regulator is controlled. This controlled output voltage can then be the primary clocked Switching power supply can be supplied as input voltage. This can be compared to a linear Voltage regulator heat losses be reduced, the switching regulator in the form of an up-converter or in the form of a combined up-down converter can.

at some applications of the electric heating system according to the invention may be desirable be to regulate the heating layer flowing through the stream. For this, the Strength this current at the output of the switching power supply by means of a current measuring device measured and a corresponding measurement signal of the power control unit supplied be, from which of the heating layer flowing through the current dependent on is controlled by this measurement signal. Between the power control unit and the current measuring device can be switched to a control unit be, but preferably integrated into the power control unit is.

Further has the switching power supply preferably one from the outside accessible Interface or a data bus for transmitting signals between the Switching Power Supply and an external device on. Thus, e.g. from the external device an external signal to the Power control unit are issued, of which the heating layer flowing electricity dependent on is controlled by this external signal. In this case, this external Device preferred a temperature gauge on, which is a signal corresponding to a measured temperature as an external signal to the switching power supply.

The electrical according to the invention Heating system can be operated energy saving, whereby the of the switching power supply maximum deliverable power below 2 kW, but preferably about 1 kW can lie. However, deliverable capacities of about 0.5 are also available kW within the limits realizable with the invention. Further Is it possible, the switching power supply via a general power supply, over a solar cell and / or over to supply a fuel station with energy. Despite the energy-saving It can operate at high loads of the electrical according to the invention Heating system may be required for drainage of heat or to provide the supply of fresh air. For this one can Air cooling and / or a liquid cooling, in particular water cooling provided being a blower, a heat-dissipating sheath, a heat sink and / or vents to be favoured.

The backing can be rigid, so that the carrier layer and the conductive Heating layer together with the electrodes form a rigid heating plate, wherein the heating layer - preferably with including the electrodes - still can be covered by another layer. But both are preferred the carrier layer as well as the heating layer formed flexible, so that the carrier layer and the conductive heating layer together with the electrodes a flexible Form heating foil, wherein the heating layer - preferably together with the electrodes - of a further flexible layer can be covered.

In the case, that the inventive electrical Heating system has a plurality of heating plates or heating foils, these can in a suitable way their electrodes are electrically interconnected. But it is also possible, on the switching power supply several outputs provide so that each heating plate or heating foil with a separate Output can be electrically connected.

The electrical according to the invention Heating system can e.g. as surface heating, be used in particular as wall and / or floor heating. When used in living spaces must, however, be considered be that a great switching power supply of aesthetic establish is often undesirable. Therefore, the switching power supply is preferred housed in a maximum volume of about 9 cm x 6 cm x 2.5 cm, which is in about the volume content of a conventional cigarette box equivalent. Thus, however, the inventive electric heating system very inconspicuous and to save space, e.g. in a wall or behind a baseboard an interior.

The The object underlying the invention is further by the use a provided with a power control unit switching power supply as Power source for an electric heater solved which an electrically insulating carrier layer, a on this arranged, electrically conductive heating layer, at least two spaced apart on the heating layer and arranged with these electrically conductive electrodes and with these electrically connected power source, wherein of the power control unit the heating layer flowing through Power is controlled.

The use according to the invention has the same advantages as the electric heating system according to the invention on, with all the aforementioned embodiments of the switching power supply or the heating transferable to the inventive use are.

The Invention will be described below with reference to a preferred embodiment described with reference to the drawing. In the drawing show:

1 a schematic view of an electric heating system according to the invention according to an embodiment,

2 a block diagram of the switching power supply to 1 .

3 a schematic diagram of the switching regulator after 2

4 an electrical circuit diagram of the switching regulator after 2 and

5 an electrical circuit diagram of the primary switched mode power supply according to 2

Out 1 shows an embodiment of the electric heating system according to the invention, wherein an electrically insulating layer 1 and an electrically conductive heating layer disposed thereon 2 are assembled to a heating plate or heating foil. With the heating layer 2 are two as electrodes 3 and 4 serving metal foil strips electrically connected, which via connecting lines 5 and 6 on a switching power supply 7 are connected, which is supplied via a voltage source with an AC voltage Uv. By means of the switching power supply 7 is over the electrodes 3 and 4 an electric current Ia is fed to the heating layer, which heats it. This is the output of the switching power supply 7 a DC voltage Ua = on the connecting cables 5 and 6 at.

Out 2 is a block diagram of the switching power supply 7 can be seen, wherein first the AC voltage Uv by means of a rectifier 8th is rectified (in a DC power supply, this rectifier can of course be omitted). This rectified voltage Ue is then used as input voltage to a switching regulator 9 supplied, which an intermediate voltage Uz to a primary clocked switching power supply 10 emits. Both the switching regulator 9 as well as the primary clocked switching power supply 10 be from a control unit 11 controlled, the control unit 11 together with the switching regulator 9 forms a module called power control unit. The of the primary clocked switching power supply 10 output voltage Ua is then from a rectifier 12 to a DC voltage Ua = rectified and to the connecting cables 5 and 6 for heating the heating plate or heating foil applied. But it is also possible, the output voltage Ua directly to the connecting cables 5 and 6 to apply.

At the output of the primary switched mode power supply 10 can be a current measuring device 13 be provided, from which a current Ia corresponding measurement signal Sm to the control unit 11 is discharged, which the switching regulator 9 and the primary switched mode power supply 10 in response to the measurement signal Sm controls such that the current Ia can be maintained despite possible disturbing influences in a desired strength.

Further, in the control unit 11 optionally an interface 14 provided by means of which electrical signals via a data bus Db with an external device 15 can be exchanged, which has a temperature measuring device, from which a temperature measurement signal corresponding to a measured temperature to the control unit 11 is delivered. According to this optional embodiment of the embodiment, the control unit controls 11 the switching regulator 9 and the primary switched mode power supply 10 in dependence on the temperature measurement signal, so that the magnitude of the current Ia can be varied in a suitable manner under changed temperature conditions. Thus, temperature fluctuations in the environment of the heating plate or heating foil can be compensated.

• 1. Der zweite Schalter S2 verbleibt im geschlossenen Zustand, wohingegen der erste Schalter S1 mit einer bestimmten Taktfrequenz periodisch geöffnet und geschlossen wird. In diesem ersten Betriebsmodus arbeitet der Schaltregler 9 als Abwärts-Wandler wobei für die Spannungen Ue und Uz die Ungleichung 0 ≤ Uz ≤ Ue gilt und die Höhe der Spannung Uz von der Spannung Ue und vom Tastverhältnis des ersten Schalters S1 abhängt.
• 2. Der erste Schalter S1 verbleibt im geschlossenen Zustand, wohingegen der zweite Schalter S2 mit einer bestimmten Taktfrequenz periodisch geöffnet und geschlossen wird. In diesem zweiten Betriebsmodus arbeitet der Schaltregler 9 als Aufwärts-Wandler wobei für die Spannungen Ue und Uz die Ungleichung Uz ≥ Ue gilt und die Höhe der Spannung Uz von der Spannung Ue und vom Tastverhältnis des zweiten Schalters S2 abhängt.

Out 3 is a schematic diagram of the switching regulator 9 to 2 seen. The rectified voltage Ue is applied via a first switch S1 to a filter chain formed by a coil L and a capacitor C, wherein between the coil L and the capacitor C, a second switch S2 is arranged. In this case, the intermediate voltage Uz is tapped parallel to the capacitor C. The according to 3 switches S1 and S2 shown in the closed state can be controlled by the control unit 11 be opened and closed, which is indicated by curved double arrows, wherein the following two operating modes are realizable according to the embodiment:

• 1. The second switch S2 remains in the closed state, whereas the first switch S1 is periodically opened and closed at a certain clock frequency. In this first operating mode, the switching regulator operates 9 as the downward converter, where the inequality 0 ≦ Uz ≦ Ue holds for the voltages Ue and Uz, and the magnitude of the voltage Uz depends on the voltage Ue and on the duty cycle of the first switch S1.
• 2. The first switch S1 remains closed NEN state, whereas the second switch S2 is periodically opened and closed with a certain clock frequency. In this second operating mode, the switching regulator operates 9 as an up-converter for the voltages Ue and Uz the inequality Uz ≥ Ue applies and the height of the voltage Uz depends on the voltage Ue and the duty cycle of the second switch S2.

By also referred to as a combined up-down converter switching regulator 9 the height of the intermediate voltage Uz can be varied within wide ranges.

Out 4 is an electrical diagram of the switching regulator 9 to 2 can be seen, wherein the first switch S1 is formed by the transistor T1 and the diode D1 and the second switch is formed by the transistor T2 and the diode D2. The in the 4 Openly shown base or gate terminals of the transistors T1 and T2 is from the control unit 11 each supplied with a control signal with a certain duty cycle, so that the transistors T1 and T2 are turned on or off in response to the respective control signal. In this case, the conductive state of the transistor T1 corresponds to the closed switch position of the first switch S1, and the blocking state of the transistor T1 corresponds to the (not shown) open switch position of the first switch S1. Furthermore, the blocking state of the transistor T2 corresponds to the closed switch position of the second switch S2, and the conductive state of the transistor T2 corresponds to the (not shown) open switch position of the second switch S2. The control signals for the transistors T1 and T2 are in the control circuit 11 generated by at least one vibrator, not shown, having an adjustment for the duty cycles of the two control signals.

Out 5 is an electrical diagram of the primary switched mode power supply 10 can be seen, the intermediate voltage Uz is supplied as an input voltage. The voltage Uz is applied to a series connection of two transistors T3 and T4, between which two diodes D3 and D4 are connected in series in the same orientation. Between the two diodes D3 and D4, a signal is tapped and a series circuit of a resistor R, a capacitor Cp and the primary winding of a transformer Tr supplied to the secondary winding, the output voltage Ua is tapped. The height of the voltage applied to the primary winding Up is dependent on the intermediate voltage Uz and thus on the switching regulator 9 adjustable. The in the 5 Openly shown base or gate terminals of the transistors T3 and T4 is from the control unit 11 each supplied with a control signal with a certain duty cycle, so that the transistors T3 and T4 are turned on or off in response to the respective control signal. In this case, the transistor T3 is preferably the inverted control signal of the transistor T4 supplied as a control signal, so that the two transistors T3 and T4 are not simultaneously turned on, but only one of the two transistors T3 and T4 conducts, while the other of the two transistors T3 and T4 locks. In 5 the two meandering control signals are shown schematically in addition to the exposed base and gate terminals of the two transistors T3 and T4, wherein the existing due to the inversion phase shift between the two control signals of 180 ° is clearly visible. The control signals for the two transistors T3 and T4 are in the control circuit 11 generated by at least one vibrator, not shown, having an adjustment for the duty cycles of the two control signals. As transistors T3 and T4 are preferably IGBT (Insulated Gate Bipolar Transistor) power MOSFETs provided, but which can also be replaced by other suitable transistors.

1

electrical insulating layer

2

electrical conductive heating layer

3, 4

electrodes

5, 6

terminating lines

7

Switching Power Supply

8th, 12

rectifier

9

switching regulators

10

primary clocked Switching Power Supply

11

control unit with vibration transmitter

13

Current measurement device

14

interface

15

external device

uv

AC supply voltage

Ue

rectified supply voltage

Uz

intermediate voltage

up

tension at the primary winding of the transformer

Ua

output voltage

Ua =

rectified output voltage

Ia

electricity through the heating layer

sm

measuring signal

db

bus

S1, S2

switch

L

Kitchen sink

C., Cp

capacitors

R

ohmic resistance

Tr

transformer

T1, T2, T3, T4

transistors

D1, D2, D3, D4

diodes

Claims (19)

Electric heating system with an electrically insulating carrier layer ( 1 ), an arranged on this, electrically conductive heating layer ( 2 ), at least two spaced from each other at the heating layer ( 2 ) and arranged in electrically conductive contact therewith ( 3 . 4 ) and a power source electrically connected thereto, characterized in that the power source is a switching power supply ( 7 ) with a power control unit ( 9 . 11 ), of which the heating layer ( 2 ) flowing through current (Ia) is controlled. Electric heating system according to claim 1, characterized in that the power control unit ( 9 . 11 ) with the switch (T3, T4) of the switching power supply ( 7 ) and is designed such that from this for controlling the heating layer ( 2 ) flowing through current (Ia), the duty cycle of the switch (T3, T4) is controlled. Electric heating system according to claim 1 or 2, characterized in that the switching power supply ( 7 ) a primary clocked switching power supply ( 10 ) having. Electric heating system according to claim 3, characterized in that the power control unit ( 9 . 11 ) with the switch (T3, T4) of the switching power supply ( 7 ) and is designed such that from this for controlling the heating layer ( 2 ) flowing through current (Ia), both the duty cycle of the switch (T3, T4) and the height of the primary winding of the power transformer (Tr) of the switching power supply ( 7 ) applied voltage (Up) is controlled. Electric heating system according to claim 4, characterized in that the power control unit ( 9 . 11 ) for controlling the level of the voltage applied to the primary winding of the mains transformer (Up) a switching regulator ( 9 ) having. Electric heating system according to claim 5, characterized in that the switching regulator ( 9 ) is an up-converter or a combined up-down converter. Electric heating system according to one of the preceding claims, characterized in that at the output of the switching power supply ( 7 ) a current measuring device ( 13 ), of which one of the thickness of the heating layer ( 2 ) flowing through current (Ia) corresponding measurement signal (Sm) to the current control unit ( 9 . 11 ) is discharged, of which the heating layer ( 2 ) flowing through current (Ia) in response to this measurement signal (Sm) is controlled. Electric heating system according to one of the preceding claims, characterized in that the switching power supply ( 7 ) an externally accessible interface ( 14 ) for transmitting signals between the switching power supply ( 7 ) and an external device ( 15 ) having. Electric heating system according to claim 8, characterized in that from the external device ( 15 ) an external signal to the power control unit ( 9 . 11 ) is discharged, of which the heating layer ( 2 ) flowing current (Ia) is controlled in response to this external signal. Electric heating system according to claim 9, characterized in that the external device ( 15 ) comprises a temperature measuring device, and the external signal is a temperature measurement signal corresponding to the temperature measured by the temperature measuring device. Electric heating system according to one of the preceding claims, characterized in that that of the switching power supply ( 7 ) maximum deliverable power is less than 2 kW, in particular about 1 kW. Electric heating system according to one of the preceding claims, characterized in that the switching power supply ( 7 ) is supplied via the general power supply, via a solar cell and / or via a fuel cell with electricity. Electric heating system according to one of the preceding claims, characterized in that the switching power supply ( 7 ) is air-cooled and / or liquid-cooled. Electric heating system according to claim 13, characterized in that on the switching power supply ( 7 ) a fan, a heat dissipating sheath, a heat sink and / or ventilation slots are provided. Electric heating system according to one of the preceding claims, characterized in that both the carrier layer ( 1 ) as well as the heating layer ( 2 ) are formed flexible. Electric heating system according to one of the preceding claims, characterized in that the switching power supply ( 7 ) has multiple outputs. Electric heating system according to one of the preceding Claims, characterized in that this electric heating system a underfloor heating a room is. Electric heating system according to one of the preceding claims, characterized in that the switching power supply ( 7 ) has a maximum volume of about 9 cm x 6 cm x 2.5 cm. Using one with a power control unit ( 9 . 11 ) provided switching power supply ( 7 ) as a power source for an electric heater, which comprises an electrically insulating carrier layer ( 1 ), an arranged on this, electrically conductive heating layer ( 2 ), at least two spaced from each other at the heating layer ( 2 ) and in contact with the electrodes ( 3 . 4 ) and the power source electrically connected thereto, the power control unit ( 9 . 11 ) of the heating layer ( 2 ) flowing through current (Ia) is controlled.