WO2011107065A1 - Method for controlling the heat output in mains-operated domestic appliances - Google Patents

Abstract

The invention relates to a method for controlling the heat output in mains-operated domestic appliances, in particular electrical drinks preparation machines, in particular for minimizing flicker disturbances, by means of an electronic circuit arrangement, wherein the output per period is controlled at different levels, wherein fast, inaccurate control is effected at a lower level and slow, finely graduated control is effected at an upper level, by composing pulse packets from mains half-cycles, at the lower level, to form a block in each case, stringing together a number of these blocks to form sections of connected half-cycles and, at the upper level, stringing together the sections to form a cycle.

Description

Method for controlling the power of heating power in mains operated household appliances

The invention relates to a method for

Power control of the heating power at

Mains-operated household appliances, in particular electric beverage preparation machines, in particular for minimizing

Flicker damage, by means of electronic circuitry. To control the heating power

usually heating elements of high power with pulse packets driven. In this type of power control of each h

Half wave (package) p (pulsewise)

turned on. It is on a switch in the

Zero crossing the mains voltage to minimize network perturbations.

If the number of half-waves of a packet (h) is chosen to be very large, the system becomes very sluggish since a new default value can only be set every h half-cycles. The

Low-temperature systems, especially radiators with low mass such as

Water heaters, then begin to waver.

Will the number of half-waves h smaller

selected (in the range of 5 to 100), the frequent switching operations lead to so-called

Flicker damage in the network. These can be selected by choosing an even smaller one

 Avoid half-wave packages h (2 to 4). But then the resolution is the adjustable one

Heating power only very low and for a fast and accurate control of a heater unsuitable.

The known in the art

Procedure is described, for example, in EP 0 868 110 B1.

One possibility, a flickerminimiertes

To provide driving method is also indicated in this document.

Based on this prior art, the invention has the object, both a fast and sufficiently accurate control of the heating power while avoiding flicker

To achieve interference.

To solve this problem, the invention proposes that the power per period in

controlled at different levels, wherein in a lower level, a fast, inaccurate control is performed and in an upper level, a slow, finely graded control is performed by in the lower level pulse packets are composed of network half-waves to a block, a number of these blocks to sections by switched

Half-waves are strung together and in the upper level, the sections are strung together in a cycle.

Preferably, it is provided that pulse packets of 2 to 4 network half-waves are combined to form one block. According to the invention, pulse packets consisting of a number of h half-waves (hereinafter referred to as block) are first defined on the lower level. Preferably, these exist

Pulse packets from 2 to 4 half-waves.

As a result, the resolution here is 1 / h × Pmax, where Pmax is the maximum power.

The time required for a block is

with f as network frequency. Th is in the

Order of magnitude 20 .. 0 ms. A number b of these blocks will now be a fixed number p in the range 0..h through-connected half-waves

strung together and in the following as

Section referred to. The average power during this section PA equals the average power during each individual block PB and is equal

At the next level, a of these sections will now be strung together, each of the sections n = l..a a number p _n

durchgeschalteter half-waves that in the range P _n = Α ··· (Α + ¹ ) n = 2 ... a. This completes cycle Z (unless additional levels are added).

This results in the mean over a cycle or a time Tz of

T _z = bT _h -a mean power

a n = \ .. a with a resolution of

 Ah

Conversely, pn can be calculated for a nominal value of the power Psoii

Typical values are h = 3, b = 7, a = 3 and a resulting resolution of 9 relative to a time of 630 ms.

By the method according to the invention, a control of the heating power in stages and levels is achieved, resulting in a reduction of EM interference / flicker in increasing a

Resolution leads. The initially asked Aurgaoe wira somn solved excellently.

A schematic representation of

Procedure is attached. There is one

Cycle Z with pulse packets p consisting of a number h of half-waves shown.

A number of these blocks B are combined into a section A.

At the next level, a number of these sections A are strung together forming a cycle Z.

Claims

Claims:

1. Method for power control of

 Heating power with mains operated

 Household appliances, in particular electric beverage preparation machines, in particular for minimizing flicker damage, by means of an electronic circuit arrangement, characterized in that the power per period is controlled in different levels, wherein in a lower level a fast, inaccurate control takes place and in an upper level a slow, Finely graded control is done by in the lower level of pulse packets of network half-waves are combined to form a block, a number of these blocks to sections through-connected

 Half-waves are strung together and in the upper level, the sections are strung together in a cycle.

2. The method according to claim 1, characterized

 characterized in that pulse packets from 2 to 4 power half-waves in each case one block

 be assembled.