EP1801684B1 - Procedure for heating and controlling the heating power and heating device - Google Patents

Abstract

The method involves providing an electrical heating device with textile threads, which forms a heatable textile (T) with a heating field (F) and a conductor in a piece of clothing. An alternating voltage is applied on a DC voltage in an alternating direction. The value of the flowing current is found and compared with a desired value in a control device (S). A cycle time from turn on- and turn-off time is adjusted for a power regulation of an extensive constant heating power in the field during each cycle in dependence of value of the measured current, where the regulation is clocked into cycles. An independent claim is also included for a heating device in a piece of clothing.

Description

The invention relates to a method for heating according to the preamble of patent claim 1, and a heating device according to the preamble of patent claim 14.

At one off WO 95/33358 known methods, the electrically conductive textile threads are supplied directly from the power source, wherein the control device comprises an on-off switch. The threads of textile nature, for example, made electrically conductive by treatment with metal or metal ions to perform resistance heating in the heating field, but consist of synthetic and / or natural thread materials to avoid metallic conductors or resistance wires in heatable textiles, especially if These are worn on the body, are perceived as very disturbing. As a power source, a DC power source or an AC power source may be used. The supply current for the heating field is in each case DC. The heatable textile can be made by weaving, knitting or the like, wherein the electrically conductive threads are incorporated in the heating field and as the current conductors. Electrically conductive, textile threads show very strong resistance scattering within a product series. Furthermore, the actual resistance changes depending on the moisture, eg by sweat, so that a uniform power supply can lead to inadmissibly varying heating outputs or failures. For example, under the influence of sweat, an electrolysis takes place at DC, which makes the conductivity of the thread material-producing metals or metal ions disappear relatively quickly from the heating field.

At one off DE 198 08 851 A respectively. AT 407 480 B known methods are surface heating elements made of an epoxy film with a rolled copper Heizleiterschicht or resistor tracks connected to a power supply device with a DC power source. For power control, a power output stage is controlled with a pulse width modulated signal. This signal is set in response to a predetermined target value for the temperature of the heating element in the heating field by means of a temperature selector. The pulse modulation circuit performs the pulse width modulation with a constant frequency pulse signal generated by an oscillator circuit. The fact that the actual resistance in the heating field is constantly changing is not considered. Because no closed loop is provided, can occur in heating operation strong power fluctuations, and is required for each surface heating element, so to speak, a tailor-made control device.

US-B-6,222,162 discloses an electric blanket, the heating element is a wound wire element, which is surrounded by insulation and is connected directly to the mains (AC). This is not suitable for mobile applications. Direct current is generated from the alternating current and applied in pulsed form. Since the controller is to calculate the heating power, constant conditions in the heating circuit are assumed. The input AC is controlled without a bridge circuit with a triac.

US Pat. No. 6,172,344 discloses (Figure 9) an electric blanket directly connected to the AC mains, and in Figure 10 a vehicle seat heating insert operated at twelve volts DC. The heating substrate contains a textile with hydrocarbon fibers rendered conductive by carbonization. Copper strips affixed to the textile form connection conductors for current control. These heating elements are not suitable for clothing that is worn directly on the skin, among other things, because they have limited mobility. The electronic circuit is used for power control on the basis of changing depending on the temperature heating current. After switching on there is a heating phase. The rising current is compared with a desired value. After reaching a desired temperature or determining the desired current is switched off with a delay. The heating element cools again before a new heating process is initiated.

The invention has for its object to provide a method of the type mentioned above and a heater for performing the method in which an adaptive power control with a control device can be carried out in a technically simple manner to under heatable textiles, for example, a product series substantially equal heating conditions with a Type of control device to achieve, ie a very uniform heating capacity, which is independent of the due to the nature of the electrically conductive, textile thread material resistance variations.

The stated object is achieved according to the method with the features of claim 1 with respect to the heating device with the features of claim 14.

By taking place in a closed loop, pulsed power control as a function of at least the value of the measured current, a very uniform heating power is achieved in the heating field, since the value of the measured current indirectly represents the Widerstandsvemältnisse in the heating field. Further, since the cycle time or the turn-on and / or turn-off time is reset for each cycle, the power control is performed in consideration of changing resistance ratios in the heating operation, e.g. in the heating field. This permanent and predictive monitoring of the electrical conditions in the heating field also offers several options for either reacting immediately or switching off in the event of a fault. Thus, the knowledge about the instantaneous electrical conditions in the heating field can additionally be used to switch off the control device or current application immediately if, for example, a short-circuit situation should result from wrinkling of the heatable textile. The heating field is acted upon by DC voltage alternating AC voltage. The change direction is expediently carried out with harmonic symmetry. The operating voltage is permanently reversed in order to avoid that in the case of moist thread material, e.g. under the influence of sweat, sets an electrolysis effect, which could lead to the disappearance of the textile thread material electrically conductive making materials. In this case, the frequency is set according to the circumstances or the specification of the thread material at least so high that an electrolysis is reliably avoided.

The heating device consisting of the heatable textile and the control device with the power source is characterized in that a relatively constant heating power can be generated in the heating field, largely independent of variations of the electrical resistance within a product series and / or fluctuations occurring during heating operation. For each cycle, the cycle time is readjusted, so that the controller exactly the power output for a limited Provides the time required for the desired heating effect. Since the control device, so to speak, adapts to the electrical conditions or compensates for changes in the electrical conditions, a variation of the heating power can be minimized with one type of control device, for example within a product series. A mass production of one type of control device consistently reduces the cost of the control device. Finally, the primary energy is optimally used by the clocking and sensitively dosed, so that a favorable ratio between the energy input and the power output can be achieved and relatively long heating times are possible even with only medium capacity of the power source. Since especially electrically conductive textile thread material, which is made conductive by plating or impregnation with metal and / or precious metal, upon application of a DC voltage, especially in wet or wet conditions, subject to an electrolysis effect, because the metal or precious metal detached by the flowing DC current and is removed, is created when controlling the heating power generated by changing direction from a DC voltage AC voltage. This avoids the electrolysis effect. The AC voltage should have a high enough frequency to reliably prevent the electrolysis effect. In this way it is ensured that the resistance properties of the thread material, which in any case are subject to wide scattering, are not changed by the electrolysis effect. The control of the heating power can be effectively carried out in various ways. Depending on the value of the flowing and measured current, either the alternating voltage is only clocked in varying cycles during the application, or it is regulated, ie raised or lowered, in varying cycles and at the same time. Another possibility is to clock the AC voltage when applying in regular cycles, while regulating the AC voltage. Finally, it is also possible to apply the AC voltage entirely without timing, and thereby regulate to keep the heating power substantially constant.

In a particularly expedient variant of the method, the actual resistance in the heating field is additionally measured in the heating mode and, depending on the measured actual resistance value, one of a plurality of different operating voltages is set. The setting of the cycle duration then takes place depending on the value of the selected operating voltage measured current. Appropriately, the operating voltage is chosen differently for the partial compensation of different actual resistances, so that the value of the measured current relatively precisely reflects the resistance conditions and the power control is even more sensitive feasible.

As another procedural measure, e.g. in order to be able to serve different heatable textiles with a basic type of control device with a certain performance, the geometric distribution of the electrically conductive threads in the heating field is already coordinated with the heating operation in anticipation of the heating operation in the production of the textile. Thus, the density of the filaments in the heating field or their effective length or their specific resistance with regard to the subsequent heating operation can be selected. The various measures, i. the clocked power control with cycle time newly defined for each cycle, the selection of the operating voltage depending on the actual resistance, and the geometric distribution or the design of the heating field, resulting in combination in an optimal condition for power utilization and for substantially the same and largely constant heating outputs ,

In principle, according to the method, the operating voltage is selected to be higher, the higher the measured actual resistance. In order, for example, to achieve a substantially constant power within a predetermined resistance range, a selection can be made between different operating voltages. There may be two or more than two different operating voltages to choose from. A voltage selection is expediently carried out in stages in order to manage with little circuit complexity, but could also be made steplessly.

In an expedient method variant, the adjustment of the operating voltage by the processor in dependence on the resistance value of the heating by means of a DCIDC-Wandiers is made.

As a further, expedient method measure, the heating operation can be set manually to one of several specific power levels as needed. Two or more power levels may be provided, eg, 3.5 and 7 watts, which the user must manually set on the controller.

Although it would be sufficient for the power control to individually set the turn-on time or the turn-off time individually as a cycle duration, both the turn-on time and the turn-off time are suitably set for each cycle. For this control routine, the processor is programmed accordingly.

The current measurement can be performed precisely with relatively little circuit complexity, if a measuring amplifier is used for this, which generates from a tapped voltage difference, for example on a weak resistance element, a measurement signal usable by the processor.

Since situations may occur during heating operation or before the beginning of a heating operation, which can endanger the user or the control device, the control device is switched off and the shutdown is signaled in the case of a determined impermissible deviation in the setpoint value comparison. The control device can only take again with the main switch by switching on and off in operation. The signaling is e.g. by means of a light emitting diode (LED). A shutdown may e.g. be made if the actual resistance, which must have a predetermined minimum value drops by a predetermined allowable deviation, or exceeds a maximum allowable value accordingly.

Since overheating could occur during discharge, it is convenient to monitor the operating temperature of the control device and, upon reaching a certain threshold temperature, e.g. 55 ° C, switched off. The shutdown is signaled.

In the heating device, the processor is expediently connected to a DC / DC converter, which adjusts the respective operating voltage according to the specifications of the processor. The respective cycle duration is then set as a function of the value of the current measured at the selected operating voltage.

In an expedient embodiment, the control device has a mechanical or manual power level changeover switch. This allows the selection of a power level. The switching can be done gradually or possibly even continuously. For example, three levels of 3.5 and 7 watts are provided, or just two stages, e.g. the heating-up phase in the heating mode takes place independently of the selected power level at the highest power level, i.e., e.g. for about 2.0 minutes with 7 watts.

The current can be measured conveniently and accurately in the resistance or current measuring power section when the detected voltage difference is processed on a weak resistance element.

Further, a temperature monitoring and shutdown device is provided to shut off, for example, when unloaded by the processor and to signal the shutdown when the temperature inside, for example, has risen to 55 ° C.

Reference to the drawings, an embodiment of the subject invention is explained, wherein Fig. 1 a symbolized block diagram of an electric heater shows.

An electric heater H in Fig. 1 It consists of an electrically heatable textile T and a control device S connected to or containing a current source A, which is usually contained in a compact housing 15.

The heatable fabric T is, for example, a garment that heats or keeps warm on the body (human or animal) a body part or a certain skin area, e.g. The textile is for example woven (weft and warp threads 1, 2) or knitted (courses 1) using natural or synthetic or mixed thread material, wherein at least one heating field F in the textile is integrated, eg interconnected weft or warp threads, or equivalent. The heating panel F contains electrically conductive textile threads 1 ', 2', i. Threads that are impregnated without metallic wires or cables, for example by applying metals or precious metals, so that metal particles or ions have penetrated into or adhered to the thread material and cause electrical conductivity. The heating panel F is connected to the textile T by means of textile threads 1 ", 2" serving as conductors, likewise electrically conductive.

In the heating field, for example, the threads 1 ', 2' are incorporated so that they form a meandering course M with contiguous loops 4. The geometric arrangement (or the equipment of the electrically conductive threads 1 ', 2') is selected in the heating field F so that a certain basic resistance range is maintained for the subsequent heating and performance of the control device S. Should, for example, in a sample with the meandering curve shown in solid lines If the specifically measured electrical resistance is too high, then at least some of the loops 4, as indicated at 4 ', can be made shorter, or vice versa, for tuning to the control device S.

The control device S includes a processor P with a memory and / or programming section 5, wherein a manually operable power level switch 7 and an on / off switch 8 are provided on, in or in the vicinity of the processor. The individual components of the control device S may be placed on one or more printed circuit boards (not shown).

Further, in the control device S, inside or outside, there is a power source A, e.g. at least one rechargeable accumulator is provided, to which a charging circuit C can be assigned. The charging circuit C may be integrated in the control device or separately housed in a charger, which is then connected to the control device to charge the accumulator (s). Furthermore, a plurality of light emitting diodes (LED) 11 are connected to the processor, which are used to signal specific operating conditions or the like. Optionally, a temperature monitoring element 12 may be provided and connected to the processor P.

Between the processor P and the contacts 3, a DC / DC converter 9, an oscillator 10, a current measuring amplifier 13 and a power amplifier 14 are provided. This module is shown as power unit L. Between the power unit L and the processor P a plurality of interconnects are provided, wherein on a conductor track, a current and / or voltage measurement U _m according to the current flowing to the processor P is supplied, while another conductor track the different operating voltage values U ₁ / U ₂ controls, which are then discharged from the power unit L. The loading of the heating field F is clocked in individual cycles Z, each of which has a certain cycle duration, for example, with alternating voltage or DC voltage alternating AC voltage from twice alternately t _i and t _o or alternately once t _i / t _o or t _o / t _i , however, for DC, for example, from a turn-on time t _i and a subsequent turn-off time t _O.

heating:

By way of example, assuming that the geometric distribution of the electrically conductive threads 1 ', 2' in the heating field F is designed so that a certain basic electrical resistance results, for example, between two limits, the power stage switch 7 can manually, for example, three stages (3, 5 and 7 watts, if necessary. Even stepless) can be selected. The current source A contains, for example, two accumulators (Li-ion cells with a total of 7.4 volts) for a DC voltage of 7.4 volts, which depends on the measured actual resistance Ri in the heating field F in the power unit L and controlled by the processor P. a certain operating voltage is increased. With these specifications, a fairly constant heat output can be adjusted within a predetermined resistance range.

As soon as the on / off switch 8 is switched on, regardless of the position of the power level switch 7, according to the program, a heating phase takes place over, for example, two minutes at the highest power level. In this case, the processor P performs a clocking in individual individually set cycles Z.

This takes place in such a way that the current flowing at the selected power stage is measured, for example in the power unit L via a voltage difference tapped at a weak resistance member, from which, for example, the measuring amplifier 13 generates the measurement signal U _{m which} can be utilized by the processor P. The measured value or the measuring signal U _m is compared with a programmed setpoint value. If the measured value lies within the specified range and if the actual resistance R _i lies between the predefined limit values, then the processor P determines the cycle duration for the current cycle Z as a function of the value of the current measured at the selected operating voltage. The next cycle is again measured and the cycle time is set again. The cycle duration for one cycle Z expediently includes a switch-on time t _i and a switch-off time t _o . If appropriate, only the switch-on time or the switch-off time is set variably, whereas the other time, according to the program, is left constant.

After the heating phase, the heating power control takes place in a closed loop on the heating F control loop, taking into account the set at the power level switch 7 power level, the operating voltage of the processor P is selected depending on the respective actual resistance R _i . This is done, for example, in that the processor P stores the measurement signal U _m just obtained when switching on or during heating operation, then the actual resistance R _{i is} measured or calculated, and then the specification for the DC / DC converter 9 is changed accordingly, to select the appropriate operating voltage for each measured actual resistance. This means that even during heating operation with a significant change of the actual resistance R _i, the processor P may select between different operating voltages, and then the respective setting of the cycle duration is effected as a function of the measured value of the current flowing at the selected operating voltage.

In this way, a largely constant heating power is delivered in the heating field.

If the temperature inside the control device, for example, rises to 55 ° C. during discharge (monitored by the temperature element 12), then the processor P switches off the control device in a locked state and signals this via an LED. The reconnection is only possible by turning off and on again the on-off switch 8.

If, during heating operation, the actual resistance R _i falls out of the preselected range, the control device S, for example, is locked by the processor P, and the switch-off is signaled via an LED 11. The reconnection is only possible by previously switching off and restarting the on / off switch 8.

Further, during the heating operation, the processor compares the actual resistance R _i with the output value stored at the beginning of the heating operation. Decreases the actual resistance by a predetermined jump, then the processor P switches off because of presumed punctual short circuits, the control device and signals this via an LED. After a predetermined waiting time, the processor P turns on In this case, turn the power back on. He checks, for example, by a measurement, whether the point short-circuit still exists, and he can continue with the normal heating operation. Such a punctual short circuit can occur, for example, by wrinkling the textile T.

The control device S is separable at the contacts 3 from the textile T. If the textile T is, for example, a T-shirt or undershirt or a comparable item of clothing, then a pocket can be incorporated into the textile in which the control device is accommodated.

With regard to possible resistance deviations in the electrically conductive thread 1 ', 2' in the heating field, e.g. the resistance of the thread prior to knitting or in entangled form is determined on a measuring device specially developed, and after the measurement result, the meandering shape or the course of the thread and the like are determined, e.g. with regard to the performance and design of the control device S.

The DC voltage supplied by the current source A is expediently converted in the AC oscillator 10 into an AC voltage in order to avoid an electrolysis phenomenon in the optionally damp or sweat-soaked heating field. In the AC oscillator 10, the alternating direction takes place with harmonic symmetry and a frequency sufficient to avoid an electrolysis effect. Undervoltage shutdown may be unnecessary, as normally the protection electronics for LI-ION batteries contain this function. The LEDs 11 are useful different colors. The charging section C is possibly dispensable or not provided in the control device S. The charging section, if present, conveniently includes a digital charge controller to limit heat buildup. If necessary, only DC voltage is applied if the thread material in the heating field is such that an electrolysis effect can not occur due to the material.

1. a) Es wird die Zyklusdauer (t_i + t_O) variierend für jeden Zyklus neu gewählt, und die gewählte Betriebsspannung gehalten, oder z.B. in Abhängigkeit vom Ist-Widerstand R_i geändert bzw. nachgeregelt.
2. b) Es wird die Zyklusdauer regelmäßig eingestellt und nur die Betriebsspannung geregelt.
3. c) Es werden gar keine Zyklen getaktet, sondern nur die Betriebsspannung geregelt.
   Für die Einstellung der jeweiligen Zyklusdauer eines Zyklus Z können gemäß der schematisierten Diagramme in Fig. 1 zumindest zwei programmierte, verschiedene Vorgangsweisen zweckmäßig sein:
4. d) Es folgt auf eine Einschaltzeit t_i mit positiver Spannung U eine Ausschaltzeit t_o ohne Spannung und danach eine Einschaltzeit t_i mit negativer Spannung U und dann wieder eine Ausschaltzeit t_o ohne Spannung.
5. e) Es setzt sich die Dauer des Zyklus Z zusammen aus mehreren abwechselnd positiven und negativen Spannungspulsen als eine Einschaltzeit t_i und einer Ausschaltzeit t_o ohne Spannung bzw. mit Spannung O.

In order to keep the heating performance of electrically conductive, textile threads when applying alternating voltage as constant as possible, several options may be appropriate:

1. a) The cycle duration (t _i + t _O ) is chosen to be different for every cycle, and the selected operating voltage is maintained, or changed or adjusted in dependence on the actual resistance R _i , for example.
2. b) The cycle duration is set regularly and only the operating voltage is regulated.
3. c) There are no cycles clocked, but only the operating voltage regulated.
   For setting the respective cycle duration of a cycle Z, according to the schematic diagrams in FIG Fig. 1 at least two programmed, different procedures should be appropriate:
4. d) It follows a turn-on time t _i with positive voltage U a turn-off time t _o without voltage and then a turn-on time t _i with negative voltage U and then again a turn-off time t _o without voltage.
5. e) The duration of the cycle Z is composed of several alternately positive and negative voltage pulses as a switch-on time t _i and a switch-off time t ₀ without voltage or with voltage O.

Claims (19)

1. Method for heating a body part with an electrical heating device (H), which comprises textile threads (1', 2', 1", 2") forming a heatable textile (T) in an item of clothing, said heatable textile having at least one heating field (F) and current conductors, made conductive by plating or impregnating with metal or noble metal, said textile threads being connected via a control device (S) to a current source (A) for direct current or DC voltage, characterised in that during heating operation, in order to avoid an electrolysis effect caused by the thread material, an alternating voltage is applied by AC conversion from the DC voltage and in the control device (S) which comprises a processor, the actual value (U_m) of the current flowing is measured and is compared with a target value and that for power regulation clocked in cycles (Z) for a substantially constant heating output (E) in the heating field (F), on every cycle (Z), the cycle duration of the switched on times and switched off times (t_i, t_o) is set depending on at least the value (U_m) of the measured current.
2. Method according to claim 1, characterised in that clocking takes place either in varying cycles or in regular cycles.
3. Method according to claim 1, characterised in that during heating operation, the actual resistance in the heating field (F) is also measured and, independently of the measured resistance value (R_i), one of a plurality of different operating voltages (U₁/U₂) is set and that the cycle duration of switched on and switched off times (t_i, t_o) is set depending on the value (U_m) of the current measured at the chosen operating voltage (U₁/U₂).
4. Method according to claim 1, characterised in that, in anticipation of heating operation, during production of the textile (T), the electrically conductive threads (1', 2') are worked into the heating field (F) with a geometrical distribution (M, 4, 4') which is determined, taking account of the efficiency of the control device (S), by resistance measurement and is correlated, for a predetermined target resistance range, with the anticipated actual resistance during heating operation.
5. Method according to claim 1, characterised in that the operating voltage (U₁/U₂) is selected to be higher the higher the measured actual resistance (R_i) is.
6. Method according to claim 2, characterised in that the operating voltage (U₁/U₂) is set in at least two steps.
7. Method according to claim 1, characterised in that, depending on need, one of a plurality of particular power stages is manually set for heating operation.
8. Method according to claim 1, characterised in that, in order to define the respective cycle duration, at least one switched on time (t_i) and at least one switched off time (t_o) are set.
9. Method according to claims 1 and 3, characterised in that, for current measurement, a measuring amplifier (13) converts a detected voltage difference into a measurement signal (U_m) which can be evaluated by the processor.
10. Method according to claim 1, characterised in that when the current/target value comparison is made, in the event that an inadmissible deviation is detected, the control device (S) is blocked and switched off.
11. Method according to claim 1, characterised in that at switch-on, the measured output value of the actual resistance (R_i) is stored and, during heating operation, is constantly compared with the measured actual resistance and that, if a resistance fall by a particular amount is detected, the control device (S) is switched off.
12. Method according to claim 1, characterised in that during discharging, the operating temperature of the control device (S) or the current source (A) is monitored and at a particular limit temperature, for instance 55°C, the control device (S) is switched off.
13. Method according to one of the claims 10 to 12, characterised in that the switching off is signalled, preferably by means of an LED (11).
14. Heating device (H) in an article of clothing, which comprises textile threads (1', 2', 1", 2") forming an electrically heatable textile which has a heating field (F) and current conductors made conductive by plating or impregnating with metal or noble metal, said textile threads being connected via a control device (S) and the current conductors to a current source (A) for direct current or DC voltage, characterised in that, in the control device (S), a processor (B) programmed for a current or voltage target value is linked to a resistance-measuring and/or current-measuring portion (L) and for regulation of a substantially constant heating output (E) in the heating field (F) said regulation being clocked in cycles (Z), is included in a closed loop via the electrically conductive threads (1', 2', 1", 2"), that the power section (L) is designed for converting the DC voltage into an alternating voltage to avoid an electrolytic effect caused by the thread material, and that the processor (B) has at least one program (5) with which, depending on the measured value (U_m) of the current flowing, the cycle duration of the switched on time and the switched off time (t_i, t_o) can be set anew for each cycle (Z).
15. Heating device according to claim 14, characterised in that the processor (P) is linked to an operating voltage adjustment member, preferably a DC/DC converter (9), that one of a plurality of different programmed operating voltages (U₁/U₂) can be set by the processor (P) depending on the measured actual resistance, and that the respective cycle duration is settable depending on the measured value (U_m) of the current flowing at the chosen operating voltage (U₁/U₂).
16. Heating device according to claim 14, characterised in that the control device (S) has a manual selection switch (7).
17. Heating device according to claim 14, characterised in that the control device (S) has a charging section (C) for the current source (A) comprising at least one chargeable accumulator.
18. Heating device according to claim 14, characterised in that a weak resistance member is provided for measuring the flowing current.
19. Heating device according to claim 14, characterised in that a temperature monitoring device and a switching off device (12, 8) are included in the control device (S).

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