DE19913760C2 - Process for the microprocessor-controlled regulation of the illuminance of an area which is exposed to changeable external light (e.g. daylight) and changeable illuminant light - Google Patents

Description

The invention relates to a method for microprocessor-controlled regulation of illuminance an area that has variable ambient light (e.g. Daylight) and changeable lighting fixtures is exposed.

In the prior art, the following are related Regulations known.

• A) a so-called mini-constant HF DIMMICO (from Osram, Germany), on its regulatory background no information is available.
• B) a light control system from Ludwig, in which one Setpoint specification by replacing a light-absorbing cap on the light sensor.
• C) in the German Offenlegungsschrift OS 196 06 674 a Procedure for controlling the lighting of a room described, in which a sensor of at least one Light source outgoing luminous flux detected and one for the control required gain factor is determined.

This process works without considering the Daylight share.

• A) the European patent EP 08 72 163 B1 and the US Patent 42 36 101 relate to a Lighting control taking into account the natural and artificial light using one whole at a time special control algorithm '.

The prior art mentioned under A has the disadvantage that that this is a space-specific system at an adjustment made with little daylight must become.

It is an object of the invention to provide a method for regulating the illuminance of an area which is exposed to extraneous light (daylight) and illuminant light

• a) the consideration of a qasi stepless setpoint specification for the Illuminance and
• b) adapting the illuminance to a changing one Percentage of extraneous light permitted.

Furthermore, it is an object of the invention for lighting fixtures with ballasts an even relativized (percentage-based) regulation of the Illuminance in the sense of an imaginary linear scaling to provide.

These objects of the invention are advantageously accomplished by solved the features mentioned in claim 1 and 2.

Advantageous further developments of the method according to the invention are marked in the subclaims.

To better understand the invention, reference is made to various Illustrations referenced. Show it:

Fig. 1 is a block diagram of the end of the control according to the illuminance;

. Figure 2 is a rough block diagram of an arrangement for implementing the method according to the invention for regulating the illumination intensity;

Fig. 3 is a schematic representation of a non-linear characteristic curve (hereinafter referred to as light output), the function of the illuminance of the lighting fixture in response to the controller output;

FIG. 4 shows a schematic illustration of the non-linear characteristic curve according to FIG. 3 and the inverse function of this characteristic curve;

Figure 5 is a schematic representation of the formation of a the illuminance detecting sensor signal, consisting of an external light component and an Beleuchtungskörperlicht- proportion.

Fig. 6 is a schematic representation for the suppression of extraneous light component from the sensor signal and for amplifying the illumination light body portion to a voltage set value;

Fig. 7 is a schematic representation of the controller and the following characteristics of the controlled system: inverse function of the nonlinear characteristic of Figure 3 and pulse width modulation with RC element to form the input variable for the ballast;.

Fig. 8, 9 and 10 are schematic diagrams for voltage formation on the RC element of FIG. 7;

The following two are intended for the illuminance of an area Components are decisive:

Foreign light ta (especially daylight) and that from one controllable lighting fixture outgoing Lighting fixture tbl.

The extraneous light component and the illuminant light component are recorded summatively via a light sensor 4 . The sensor signal Uges (e.g. a voltage value) formed on the basis of the incident light is composed of the sum of a voltage value Uta for the daylight component and a voltage value Ubl for the lighting element light component.

Uges = Uta + Ubl

The course Uges = f (t) (t = time) is subject to time Fluctuations, e.g. B. by daylight or Reflection fluctuations in the illuminated area due could be.

Fig. 6 shows a schematic representation for the suppression of the initial extraneous light component from the sensor signal Uta Uges and amplifying the lighting state light-Ubl proportion to a voltage read-only Usolid.

The value for Ufest can be 5 V DC, for example be.

Before the actual regulation begins, the maximum is reached possible light emission (illuminance) of the Luminaire declining share Ublmax of the sensor Signals determined as follows:

First, the sensor signal is determined, which is at a lighting fixture that does not emit light;  however, the method according to the invention also covers the Possibility of a state of lowest light emission or Illuminance (e.g. lowest dimming level) of the Lighting fixture to go out.

In the former case, the entire sensor signal Uges consists only of the value Uta - a, which is based on the initial extraneous light component.

Uges = Uta - a

This value Uta - a is automatically recorded and saved. The sensor signal for the maximum possible light output of the lighting fixture is then measured taking into account the influence of the initial extraneous light component Uta - a:

Uges = Ublmax + Uta - a

Ublmax is the portion of the sensor signal based on the maximum possible light output by the lighting fixture. The previously stored value Uta - a is subtracted from the value Uges = Ublmax + Uta - a, thereby determining the value Ublmax:

(Ublmax + Uta - a) - Uta - a = Ublmax.

The Ublmax value becomes a predetermined fixed value Ufest (e.g. 5 V DC voltage) and the required Gain factor v automatically determined and for one saved later access.

With acquisition and storage of the value Uta - a and with Determination and storage of the gain factor v are the Prerequisites for the actual process Control procedure created, which is described below.

Fig. 2 is a rough block diagram showing an arrangement for implementing the method according to the invention for controlling the illumination intensity.

In this block diagram is the controllable light emitter Lighting fixture with 1 and the one required for it  electrical ballast EVG designated 2. Various Lighting fixtures require ballasts for their operation. For example, ballasts for discharge lamps are the following Important reasons: initiation of discharge and stabilization the operating current or the power consumption.

The current proportion of daylight for sensor 4 is denoted by ta, the current proportion of lighting fixture by tbl. Both components tbl and ta are summatively added by the sensor 4 as voltage values

Uges = Uta + Ubl recorded.

Uta is the voltage value for the current proportion of daylight ta; Ubl is the voltage value for the current one Illuminant light component bl.

Block 5 contains the suppression of the initial daylight component Uta-a from the Uges signal in connection with FIG. 1 in block E., forming a difference signal

dU = Uges - (Uta - a) = Ubl + Uta - (Uta - a)

The realization of a circuit for block 5 takes place according to the usual knowledge of the prior art, for. B. by an analog or digital subtraction circuit, taking into account the stored value (in analog or digital form) Uta - a.

Block 6 relates to the amplification of the voltage value dU with the stored amplification factor v

Ui = v. you

According to the state of the art, such a multiplication also stands for Technology widely known diverse Realization options available.

For reasons of clarity and simplification, the Presentation of related circuit details (also  including any necessary digital / analog Change) waived.

The value Ui is formed in block 6 as a relativized variable (e.g. as a percentage):
100 (%) correspond to Ufest = Ublmax. v
Depending on the size of Ui, there are corresponding percentages:
For Ui = 0.5 Ufest the result would be 50 (%)
For Ui = 0.25 Ufest the result would be 25 (%).
Etc.

If a digital controller 3 is used and if the Ui values are in analog form, block 8 is preceded by a generally conventional analog / digital converter (not shown) which forms relativized digital values Ui between 0 and 100.

For the sake of simplicity, we will not do that here either a very small additional one (e.g. over 100 Area) must be present in order to be about the size Ufest outgoing sensor signal (maximum in the extreme case Light emission from the lighting fixture and an increase in extraneous light beyond the Uta - a value).

Analogous considerations also apply to the area around zero.

Block 7 contains a setpoint specification S for the area illuminance. Such a setpoint can be specified automatically or manually. A manual specification can e.g. B. via a linear potentiometer with a (e.g. in% values) relativized setting range between 0 and 100. The setting position 100 (%) specifies the maximum possible illuminance in the lighting area, the setting positions below correspond to portions of this maximum value. It is also possible "without looking" at the setting values of the potentiometer to set a target value for the illuminance by changing the setting of the potentiometer until a desired illuminance has been obtained "by eye inspection".

At this point it should be emphasized that at Changes in the setpoint a quick control (or Control) for setting the illuminance in the Lighting area should take place so that the setpoint The person operating the potentiometer does not have to wait a long time, until the desired illuminance is reached. With in other words, a change in the setpoint must be almost immediate its effects can be observed. Should the Illuminance can be changed according to light sensation, so the extent of the change can be adjusted accordingly Rotation tests on the potentiometer directly watch (without significant delay). The relativized Setpoints (between 0 and 100) are denoted by S.

Block 8 represents a difference element for forming the difference D between S and Ui:

D = S - Ui

For D there can be both positive and negative values surrender.

To realize such difference-forming circuits Customary circuits known from the prior art used, e.g. B. differential amplifier. Likewise, a Difference formation also program-controlled (e.g. with the help of Analog / digital converters).

For a better understanding of the advantages of the invention, the following should be noted in this connection: If the potentiometer range referred to both the extraneous light component and the illuminant light component when a setpoint was specified, only a very small (too small) would remain for influencing the illuminance ) Rotation range. This reason alone justifies the suppression of the external light component Uta - a in the sensor signal, after which approximately the entire available range of rotation of the potentiometer is now available for a user-friendly setpoint specification. Analogous considerations also apply to controller 3 .

The difference value D is fed as an input variable to a controller 3 , the output value R of which serves to reverse the UF of the (non-linear) characteristic curve K (light output of the lighting fixture ( 1 ) including the ballast with an upstream RC element as a function of the controller output variable R) To control the ballast.

This gives a so-called "linearization", which is can be described as follows:

For this it is assumed that the ordinate values of the characteristic curve K are in a relativized form (e.g. as a percentage) ( FIG. 3), i. h occur for the input value E of the ballast as an x value and the light output value L of the lighting fixture as a y value. B. (%) - values between 0 and 100. The x value 100 (%) stands for the maximum possible light output of the lighting fixture of 100 (%); the x value 80 (%) for a light output L of 50 (%).

Lead due to the non-linearity of the characteristic curve K. Equidistant changes in the x values depending on the position of the Working point to differently large changes in the Light output L of the lighting fixture.  

A smooth regulation in the steep curve area is difficult because here with small changes the Input variable relatively large changes in the output variables (Risk of vibration tendency).

However, the aim of the method according to the invention is that Ballast with RC circuit and thus the non-linear Control characteristic K so that with the input values for the Ballast the light output values L (in%) of Luminaire changed in linear scaling if possible can be.

How this goal is achieved is described below: The controller output value R, a (in%) relevant quantity between 0 and 100, is intended to bring about a relative light output of the lighting fixture corresponding to this value. A controller output value R = 15 should e.g. B. lead to a 15% light output of the lighting fixture. A controller output value R = 50 should cause a 50% light output of the lighting fixture; etc .. If with such a governor output value R directly the non-linear characteristic K are directly controlled (Fig. 3 and Fig. 4), so such a correlation would not be possible, because for E = 15, a light output value of L would result in approximately 10, and for E = 45 a light output value of L = 15.

In order to achieve linear scaling as required, quasi between controller output and nonlinear characteristic K (whose x value the input value E of the ballast with RC element corresponds) to the inverse function UF of the nonlinear characteristic curve K "switched", which simulate software or hardware leaves.

The ordinate values of the inversion function UF ( FIG. 4) are also relativized data (in%) between 0 and 100. The inversion function UF is "controlled" with the controller output variable R as an x value; the associated y-value Z is "read" for this x-value R; This y value Z of the inversion function UF is then used as the x value E for controlling the ballast.

This step can be followed using the inverse function UF Z = f (R) shown in FIG. 4 and the characteristic curve KL = f (E): z. B. corresponds to the x value R = 50 according to point P1 'of the inverse function UF the y value Z = 80; this value Z = 80 is used as the x-value E for the characteristic curve K, for which a y-value L = 50 results according to point P1. This means that the controller output value R = 50 leads to a 50% light output of the lighting fixture via the reversing function UF.

Analogously to this example, it can also be seen in FIG. 4 how a value R = 15 according to point P2 'points the inverse function to a z-value 45, which as x-value E (input value of the ballast) according to point P2 on the characteristic curve leads to a light power output L of 15 (%).

The controller 9 itself can be a conventional I, PI or PID controller (I = integral; P = proportional; D = differential).

In the present case it is a so-called quasi analog control. The sampling time of the digital control is very small compared to the dominant time constant of the Control loop.

Essential and indispensable for the realization of the The inventive method is a type of controller that a Integral function includes: This part guarantees that none "Jumps" occur with strong changes in light. The Normal operation should be "jump-free"; furthermore  no permanent control deviation occurs.

An additional P component of the I controller causes the Responsiveness of the controller is increased.

When changing setpoints, the controller must - as required be fast, which is achieved by connecting a P component can be.

An additional D component gives a PID controller. Due to its differential D component, such a still has one greater speed than the PI controller. With the help of the D- Time constants of the controlled system can be compensated become.

The inverse function UF of the characteristic curve K can be program controlled from the z. B. digitally stored Derive characteristic data and for a certain predetermined Save the resolution (coordinate grid).

The recording of the characteristic data can also done programmatically by for a sequence of Input values of the ballast corresponding to these Values of the light power output are measured and stored.

Should - as in the case of a practical exemplary embodiment for realizing the invention, the ballast (of the TYPE EL 2 × 55 HFC2F from Helvar, Finland) for a discharge lamp as a lighting fixture (of the type Osram DULUX 55 W / 21-840) have an analog input , the (in the case of a digital controller used and a digitally stored reversing function of the characteristic) digital y coordinate value Z must first be converted into an analog (DC voltage value).

For such a D / A conversion, e.g. B. a low-pass element consisting of an RC element can be used in connection with pulse width modulation (block 10 in FIG. 2; details in FIGS. 7, 8, 9, 10).

Assume that a controller output value would require a (digital) y value of Z = 75 according to the inverse function, which is used for a corresponding pulse width modulation. Control value is determined by the value 75, by means of which an imaginary pulse P is generated in a period T according to FIG . (Analogously, a pulse would be generated for a Z value of 50, which fills 50% of this time T, etc.). That is, the pulse P has a width of 75% of the imaginary signal period T or the hatched pulse area makes up 75% of the total dotted area for the signal period T.

The control data of the pulse P are used for the on / off control of an imaginary switch SW ( FIG. 7) in such a way that the switch is switched on ("on") at the time of the pulse P and switched off ("off") at the remaining time in the period T is. In the example Z = 50 ( FIG. 9), the switch would be 50% on and 50% off during the period T.

The RC low-pass element ( FIG. 7), the capacitor C of which is supplied with a voltage U available in the ballast EVG 2, is switch-controlled by means of the control data effecting pulse width modulation.

As a result of the switch control, the voltage U, the acts as an input variable for the ballast, on Capacitor C changed.

Figs. 8, 9 and 10 show schematic representations of the stress development at the switch controlled RC-Tiefpaßglied.

FIG. 9 shows how the voltage U across the capacitor C builds up during the "off" time of the pulse (switch SW open) in the time period and how it develops during the "on" time (switch SW closed) dismantles again. The sawtooth-like (e-function-related) voltage curve becomes smoother the higher the switch duty cycle.

Fig. 10 shows the temporal voltage curve of the capacitor voltage U for a very high Schaltertastfrequenz for different pulse width modulation values 25%, 50% and 75%.

If the daylight component changes ( FIG. 2) after the Uta-a value (and the amplification factor v) has been stored once, this is noticeable by a change in the Ui value on the differential element 8 . This change is automatically recorded by the control. The gain factor v is advantageously determined only during the initial installation, while Uta-a is recorded after each start-up.

If the proportion of daylight rises, the light output of the lighting fixture is regulated back in accordance with the target specification in block 7 for constant lighting.

When the setpoint changes, the input variable D of the controller formed by the differential element 8 also changes, which in turn causes a rapid automatic readjustment. It is also possible to readjust the light output.

Changes in the reflection of the illuminated area are reflected in the Sensor detects and can be taken into account by the control  become.

In this context there has been a sluggish timing proven that is not immediately, but only after a long time affects. This way, it doesn't happen immediately a change in lighting when e.g. B. a completely black dressed (i.e. highly light absorbing) person temporarily reaches the detection range of the sensor. Likewise, there will be no immediate change in lighting result if e.g. B. crawls a fly over the sensor and temporarily disrupts the sensor function.

However, such a "sluggish regulation" would be disadvantageous if it as also described above also on the Setpoint specification S refer. Here's a quick change offered, since the operator changes the Would like to convince setpoint quickly how it works affects.

For this reason, if the setpoint changes, it becomes sluggish Regulation overridden and due to a "quick regulation" or direct control while tracking the controller Output variable R replaced.

Fig. 1 shows a block diagram for illustrating the inventive method for controlling the illuminance of a region of the external light (eg. B. daylight) and controllable lighting unit is exposed to light.

In block A, the illuminance is recorded of the area in question by means of a light sensor. This area should initially only be under the influence of  Incident light (e.g. daylight). In this case it is Turn off the lighting fixture (or just in the lowest dimming level), that means that the Light sensor signal has no share on the Lighting fixture would be attributed. That only on that Light sensor signal to be traced back to the initial extraneous light is included Initial foreign light component signal Uta / a referred to and also saved because in the later course of the scheme on this Value is used.

In block B, the detection of the illuminance of the area in question takes place, which is now not only under the influence of daylight but is additionally exposed to a maximum light output by the lighting fixture. In other words, the light sensor now supplies a signal Uges, which consists of two components: the component Uta - a, which is due to the initial extraneous light and the component Ublmax, which is based on the maximum light output of the lighting fixture. This value Uges is saved because it is used in the subsequent step.

Uges = Ublmax + Uta - a

In block C, the determination and storage of a Gain factor v, where the product of v and the difference dU between Uges and Uta - a corresponds to a predeterminable fixed value Ufest. On this Gain factor is in the course of the following regulation resorted to. Its purpose is at the maximum Light output of the lighting fixture linked.

Blocks A, B and C are used to carry out the Regulation of the illuminance determines required sizes,  namely the initial extraneous light component signal Uta / a and Gain factor v.

Block D refers to the formation of the current light sensor signal

Uges = Uta + Ubl

with a current daylight component Uta and a current one Lighting fixture light Share Ubl.

In block E, the light sensor initial external light component signal Uta / a stored in block A is subtracted from the current light sensor signal Uges determined in block D. The difference is

dU = Uges - Uta - a

In block F, the product Ui is formed from the gain factor v stored in block C and the difference value dU determined in block E:

Ui = v. you

as a relative size (in%). That is, all possible Ui values are between 0 and 100 as percentages or the like, whereby each Ui value is related to the maximum possible Ui value.

In block G, the difference D between the setpoint value for the illuminance specified in block H and the product value Ui is formed

D = S - Ui.

This difference value formed in block G is called Input variable used for an I, PI or PID controller. The output value R formed by this controller, also a relativized size is used in block J, about the  Reverse function UF of the (non-linear) characteristic of the Ballast with upstream RC element and the Lighting body an input value E for controlling the Ballast to determine. The reverse function is used for this of the characteristic curve K. The inverse function UF is preferably in stored in digital form with relativized ordinate values. For a controller output value R, e.g. B. as the x value of Reverse function UF used, the associated y-value Z read out or determined (e.g. by interpolation) and then as indicated in block K as the input value of the Ballast with RC element of the lighting fixture used. Subsequently, the regulation is again with block D continued.

If Uta - a is a very low or a very high value represents and "during the day" the amount of daylight strongly increases or decreases, any readjustment would be through Setpoint specification difficult or not possible. For this reason is a program-controlled tracking of the Uta - a value displayed, especially in the event that a setpoint change no further increase or decrease in Allows light output.

For temporarily occurring changes in reflection, which determined via an automatic plausibility check is an automatic tracking of the Gain factor also shown.

It was described above that to determine the Light sensor initial external light component signal Uta - a der Lighting fixture is initially turned off.  

However, the method according to the invention also covers the case in which the lighting fixture is not completely switched off, but, for. B. emits a minimum value of light in the lowest dimming level. For such a situation, a modified variable U'ta-a is determined, which is composed of the value based on this minimum value and the value due to the external light. In the further course of the method, the value U'ta - a is subtracted from the value Uges of the current illuminance measured by the light sensor ( 4 ), which is composed of the current illuminant light component Ubl and the current extraneous light component Uta (Uges = Ubl + Uta). All other process steps correspond to those described in connection with FIG. 1. The part of the sensor voltage that can be attributed to a maximum light output is denoted by U'blmax and the product of v 'and U'blmax by U'fest.

The method described above can also be used by several Use light sensors, weighted from their measured values or unweighted, the "actual sensor output signal" is formed.

Claims (11)

1. A method for microprocessor-controlled regulation of the illuminance of an area which is exposed to variable external light and changeable illuminating body light, characterized in that the illuminance

• a) predetermined by a changeable setpoint (S) and
• b) is measured by at least one light sensor ( 4 );

that before the start of the scheme
aussendendem with no light illumination body (1) of returning to the external light value Uta by the light sensor (4) - is a measured and stored (11) and
at maximum light output from the lighting fixture ( 1 ), the light sensor ( 4 ) determines the value Ublmax which is based on the lighting fixture light and which is amplified to a predeterminable fixed value Ufest and
that the required amplification factor v is stored ( 11 );
that the value Uta - a is subtracted from the value of the current illuminance measured by the light sensor ( 4 ), which is composed of the current illuminant light component Ubl and the current extraneous light component Uta (Uges = Ubl + Uta)
the resulting difference value dU (dU = Uges - Uta - a) with the gain factor v to the product value Ui = dU. v is multiplied;
that the difference D between the target value S and the product value Ui is formed
and is used as an input variable for an I, PI or PID controller ( 3 ) and
that the light output of the lighting fixture ( 1 ) is changed by the controller output variable. 2. A method for microprocessor-controlled regulation of the illuminance of an area which is exposed to variable external light and changeable illuminating body light, characterized in that the illuminance

• a) predetermined by a changeable setpoint (S) and
• b) is measured by at least one light sensor ( 4 );

that before the start of the scheme
in the case of a lighting device ( 1 ) emitting a minimum value of light, the light sensor ( 4 ) measures and stores the value U'ta - a which is based on this minimum value and the extraneous light ( 11 ) and
at maximum light output of the lighting fixture ( 1 ) by the light sensor ( 4 ) the value U'blmax, which is reduced to the minimum value of the lighting fixture light, is determined, which is amplified to a predeterminable fixed value U'fix and
that the required amplification factor v is stored ( 11 );
that the value U'ta - a is subtracted from the value of the current illuminance measured by the light sensor ( 4 ), which is composed of the current illuminant light component Ubl and the current extraneous light component Uta (Uges = Ubl + Uta)
the resulting difference value dU (dU = Uges - U'ta - a) with the gain factor v to the product value Ui = dU. v is multiplied;
that the difference D between the target value S and the product value Ui is formed
and is used as an input variable for an I, PI or PID controller ( 3 ) and
that the light output of the lighting fixture ( 1 ) is changed by the controller output variable. 3. The method according to claim 1 or 2, characterized in
that a ballast ( 2 ) required for its function is connected upstream of the lighting fixture ( 1 ),
the light output of the lighting fixture ( 1 ) as a function of the controller output variable R represents a nonlinear characteristic curve K;
and that the ballast ( 2 ) is controlled with a value which, according to the inverse function UF, is to be assigned to the non-linear characteristic curve K of the controller output variable R as a coordinate value. 4. The method according to any one of claims 1 or 3, characterized in that the setpoint S and product value quantities Ui or the setpoint S, the product value Ui, the controller output variables R and the Characteristic and inverse function coordinate values - e.g. B. as Percentage - are relativized. 5. The method according to any one of the preceding claims, characterized, that the change in the light output of the Lighting fixture temporally when changes in ambient light occur slower than with a setpoint change. 6. The method according to claim 1, 2 or 3, characterized in that the controller ( 3 ) is a digital controller. 7. The method according to claim 3, characterized in that the ballast ( 2 ) can be controlled analog or digital. 8. The method according to claim 3 or 4, characterized that the reverse function (UF) is stored digitized. 9. The method according to any one of claims 3 to 7, characterized in that the coordinate output value R corresponding to the controller output value (Z) of the reversing function (UF) is converted by a switch-controlled pulse-width modulation into an analog input signal for the ballast ( 2 ). 10. The method according to any one of the preceding claims, characterized, that the Uta - a or U'ta - a value is program controlled is changed when the amount of extraneous light changes.   11. The method according to any one of the preceding claims, characterized, that the gain factor v is program controlled when the reflectivity of the area has changed significantly is changed.