EP0868110A1 - Flicker minimizing triggering method for at least one heating element of a linear heating apparatus - Google Patents

Abstract

The method involves using electronic switches for at least one heating element. The power per period is controlled via the size of pulse packets consisting of a number of mains half waves. Pulse packets of equal polarity are arranged in sequence in equal numbers at the start and end of the period depending on the power. Further half waves of a different polarity are arranged in sequence in association with a pulse packet above 50 per cent depending on a further power. The polarities of the mains half waves are cyclically interchanged after each period.

Description

The invention relates to a control method according to the Genus of the preamble of claim 1 and the Claim 3.

In known heating devices is one to one Heating resistor in series switch one sensitive influencing of the temperature of the dispensed Warm air depending on an adjustable setpoint possible. For this purpose, the switch is used in a known manner controlled by a pulse packet controller. The ones from The heating power emitted by the heating resistor is pulsed activation of the switch, generally one Triac, set in the voltage zero crossing. Since that Any ratio of pulse lengths to pulse pauses can be selected, the heating output in this way between zero and the maximum by the radiator feasible performance can be varied almost arbitrarily.

At the voltage feedback on power grids are in recently increased requirements (flicker standard EN 61000-3-3). For example, one for Hand-held hair dryers or drying hoods are used too switching power of typically> 1000 W. According to regulations, such large switching intervals are required that the time constants of fast radiator systems are clear exceeded and thus excessive temperature fluctuations the exhaust air occur. The allowed Switching times are only used for hand hair dryers and Drying hoods significantly lower nominal power acceptably small. A solution according to DE 40 23 250 A1 goes the way, the radiator in two or more Split low-power resistors, and a rapid successive, simultaneous switching of the To prevent partial resistances in a suitable manner. This However, the process is technically / constructively complex and only limited for retrofitting in existing devices suitable.

The object of the present invention is therefore a to create a flicker-minimized triggering process that simple measures keeping an undivided Radiator allowed, but optionally also in systems with divided heating strands can be used.

This task is performed according to the distinctive part of the Claim 1 and claim 3 solved. Beneficial Further training results from the subclaims.

The invention is based on several exemplary embodiments described in more detail.

Figur 1

ein Blockschaltbild einer Leistungssteuerung;

Figur 2

ein Blockschaltbild einer Temperaturregelung,

Figur 3

verschiedene Pulspakete eines ersten Ausführungsbeispiels;

Figur 4

verschiedene Pulspakete eines zweiten Ausführungsbeispiels, und

Figur 5-7

jeweils zwei aufeinanderfolgende Pulspakete.

It shows:

Figure 1

a block diagram of a power control;

Figure 2

a block diagram of a temperature control,

Figure 3

different pulse packets of a first embodiment;

Figure 4

different pulse packets of a second embodiment, and

Figure 5-7

two successive pulse packets each.

Figure 1 shows a basic block diagram of a Flicker-minimized power control using electronic switch for at least one heating element a network-operated heating device, wherein a Microcontroller by means of a zero crossing detection of the Network half-waves detects positive and negative half-waves and a circuit breaker with corresponding half-wave pulse packets controls. Via a power setting facility a certain performance can be specified.

A basic block diagram of a temperature-dependent (regulated) power control is shown in FIG. 2, wherein a temperature setpoint is specified, which by means one thermally coupled to the heating element Temperature sensor detected actual temperature from Microcontroller is compared and the circuit breaker controlled with appropriate pulse packets.

In FIG. 3, the power control method in a first exemplary embodiment is described in more detail using the example of seven pulse packets 2, 3, 11-14, 21. The power per period T is controlled by the size of pulse packets 1-21. The pulse packets 1-21 consist of a series of network half-waves A, B, C, the half-waves A, B of a first polarity in the same number being arranged in succession depending on the power at the beginning and end of the period T. With more than 50% power control, the pulse packet 12-21 is assigned further half waves C of a second polarity in succession depending on a further power, the polarities of the network half waves A, B, C being exchanged cyclically after each period T. Cyclical swapping has the advantage that the network is loaded with few DC components. For reasons of illustration, a period T corresponding to 20 full network waves (= 40 network half-waves) is selected here (as also according to FIG. 4). In practice, a period T corresponding to 50 full network waves (= 50 Hz = 1 s) should be common. After the selected period T, 21 power levels from 0% to 100% are possible, as the following table shows. Half waves Performance in% Pulse package A B C. 0 0 0 0 1 1 1 0 5 2nd 2nd 2nd 0 10th 3rd 3rd 3rd 0 15 4th 4th 4th 0 20th 5 5 5 0 25th 6 6 6 0 30th 7 7 7 0 35 8th 8th 8th 0 40 9 9 9 0 45 10th 10th 10th 0 50 11 10th 10th 2nd 55 12th 10th 10th 4th 60 13 10th 10th 6 65 14 10th 10th 8th 70 15 10th 10th 10th 75 16 10th 10th 12th 80 17th 10th 10th 14 85 18th 10th 10th 16 90 19th 10th 10th 18th 95 20th 10th 10th 20th 100 21

The half-waves C can - as shown - in the middle as well be arranged at the beginning or end of the period T.

In FIG. 4, the power control method is described in more detail in a second exemplary embodiment, using the example of seven pulse packets 2 ', 3', 11'-14 ', 21'. The power per period T is controlled via the size of pulse packets 1'-21 '. The pulse packets 1'-21 'consist of a series of network half-waves D, E, the half-waves D of a first polarity at the beginning of the period T and the half-waves E of a second polarity at the end of the period T being arranged in succession in equal numbers depending on the power . Of the 21 pulse packets 1'-21 '(corresponding to 21 power levels), only the pulse packets 2', 3 ', 11'-14' and 21 'are shown here. The corresponding 21 power levels could be controlled manually by means of a corresponding step switch or the like via a microcontroller, or a temperature control according to FIG. 2 could optionally be provided. After the selected period T, the 21 power levels (0% to 100%) are built up in 5% power steps, which is shown in the following table. Half waves Performance in% Pulse package D E 0 0 0 1' 1 1 5 2 ' 2nd 2nd 10th 3 ' 3rd 3rd 15 4 ' 4th 4th 20th 5 ' 5 5 25th 6 ' 6 6 30th 7 ' 7 7 35 8th' 8th 8th 40 9 ' 9 9 45 10 ' 10th 10th 50 11 ' 11 11 55 12 ' 12th 12th 60 13 ' 13 13 65 14 ' 14 14 70 15 ' 15 15 75 16 ' 16 16 80 17 ' 17th 17th 85 18 ' 18th 18th 90 19 ' 19th 19th 95 20 ' 20th 20th 100 21 '

From an output of 55%, the half-waves D, E - each after further power - in corresponding full waves about. The resulting DC component is at its maximum permissible value incorporated in the standard EN 61000-3-2 and may be a maximum of approx. 1160 W with pure half-wave control be. To further relieve the power grid suggested the polarity of the pulse packets in for the Flickernorm harmless intervals, cyclically too swap in order to reduce the average component (Figure 6). Furthermore, the direct current load of Contacts u. reduced. As measurements show, at good control quality and fast undivided radiator system more than 1000 W in compliance with the limit values of the EN standard 6100-3-2 with this method a short-term power Pst (Power short time / measuring time = 10 minutes) to values far below the limit of 1.

FIG. 5 shows two successive periods T ₁ and T ₂ with two identical pulse packets 13 ', 13' (FIG. 4), a full-wave jump X occurring here when the period changes, which is avoided in a further development of the invention according to FIG. 6 (as well as the duration of half-waves of the same polarity) that the polarities of the half-waves D ', E' are cyclically exchanged after each period T ₁ (T ₁ , T ₂ etc.).

FIG. 7 shows two pulse packets 13, 13 (FIG. 3), the polarities of the half-waves A, B, C of the period T _{1 being} exchanged cyclically ( T 2nd = A ', B', C '/ T 1 = A, B, C ), which minimizes the DC component.

For actuation beyond a heating element, it is proposed that a first heating element with the first and a second heating element with the second polarity of half-waves A, B, C or D, E be applied, or that a first heating element be cyclically applied with the first period T ₁ and a second heating element with the second period T _{2 is} applied. In a further development, the power process is integrated in a temperature control, and a heat treatment device for head hair can be provided as the heating device.

Claims (8)

Flicker-minimized power control method using electronic switches for at least one heating element of a mains-operated heating device,
characterized, that the power per period (T) is controlled via the size of pulse packets (1-21), that the pulse packets (1-21) consist of a series of network half-waves (A, B, C), the half-waves (A, B) of a first polarity in the same number depending on the power at the beginning and end of the period (T) are arranged sequentially, that the pulse packet (12-21) more than 50% power control depending on a further power further half-waves (C) of a second polarity are assigned in succession, and that the polarities of the network half-waves (A, B, C) are exchanged cyclically after each period (T). Method according to claim 1,
characterized in that the half-waves (C) of the second polarity are arranged substantially in the center of the period (T). Flicker-minimized power control method using electronic switches for at least one heating element of a mains-operated heating device,
characterized, that the power per period (T) is controlled by the size of pulse packets (1'-21 '), and that the pulse packets (1'-21 ') consist of a series of network half-waves (D, E), the half-waves (D) having a first polarity at the beginning of the period (T) and the half-waves (E) having a second polarity at the end of the period ( T) are arranged consecutively in the same number depending on the performance. Method according to claim 3, characterized in that the polarities of the half-waves (D, E) are exchanged cyclically after each period (T). A method according to claim 1 or claim 3, characterized in that a first heating element with the first and a second heating element with the second polarity of half waves (A, B, C) or (D, E) is applied. A method according to claim 1 or claim 3, characterized in that a first heating element with the first period (T ₁ ) and a second heating element with the second period (T ₂ ) is applied cyclically. Method according to claim 1 or claim 3, characterized in that the power control method is integrated in a temperature control. Method according to Claim 1 or Claim 3, characterized in that a heat treatment device for head hair is provided as the heating device.

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