HK1148897B - Control of lighting devices over a modulated dc bus - Google Patents

Abstract

Illuminant means-operating devices are controlled by means of a central rectifier/PFC unit (2, 10), which supplies several illuminant means-operating devices (1) by means of at least one DC output circuit (11). The DC supply voltage is modulated in a power line technique (17) to high frequency digital control signals, which can be read out through power line demodulators (15) into the operating devices (1) and evaluated for controlling the associated illuminant means (5).

Description

The present invention relates to the control of several lighting controls from a central unit.

The invention is based on a system schematically shown in Fig. 2. In this example, the luminaire is a gas discharge lamp 5 controlled by an electrical ballast (EVG) 1 as an operating device. In the usual way, this EVG 1 has a rectifier with power factor correction (PFC) 2, an electrolyte storage capacitor 4 and an RF inverter 3 which in turn controls the gas discharge lamp 5 via its output circuit 6.

In addition, an emergency lighting control 7 may be provided.

The rectifier 2 in the EVG 1 is normally supplied with AC voltage 9, e.g. mains voltage.

At the same time, it is known that EVG 1 can be controlled by a digital or analogue bus control 8 to start, dim or turn off lamp 5 It should be noted that at this stage of technology, each lamp operated device (EVG 1) has its own rectifier 2 with PFC circuit. Such a PFC circuit reduces known upper waves in the input current.

EP1244337 A1 describes a lighting system with an electrified line (1) and a variety of lighting devices connected to the said line, each of the lighting devices (3) a high intensity discharge lamp (HID) lamp (L), with a power supply (5) connected to a first subset of the components of a power supply circuit, and that the electrified line (1) is connected to a power supply module (7) with the other electrical components of the power supply circuit all of which are assigned to lighting devices (3).

US5539388A describes a telemetry and control system for use in DC power onboard networks as revealed in automobiles or other vehicles. The system features a master transmitter that encodes data as a sequence of current pulses modulating the DC supply voltage.

The present invention is therefore based on the idea of a control for lighting controls which would allow the production of controls at a lower cost.

The central point of the invention is that the rectifier/PFC unit is no longer locally located in each operational device but is centrally located for several operational devices.

In particular, the present invention deals with the aspect of how operational devices can be supplied in a simple manner via the DC output circuit not only with the required operating power but also with control signals.

More specifically, the above problem is solved by the features of the independent claims, which further develop the central idea of the invention in a particularly advantageous way.

The present invention therefore proposes a method for controlling luminaire actuators by means of a central rectifier/PFC unit supplied with alternating voltage, whereby this central unit supplies several luminaire actuators by means of at least one DC output circuit, modulating the DC supply voltage of the output circuit according to a Powerline technique by high frequency digital control signals. These Powerline control signals can then be evaluated locally in the actuators by the Powerline demodulators provided there from the DC output circuit and for controlling the assigned luminaire.

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A powerline modulator for modulating control signals fed to the DC output circuit may be provided in the DC output circuit or in the central rectifier/PFC unit.

To switch off a light source, a power line demodulator in an operating device may be given a power-off command, which will switch off the assigned light source via a power line control command.

For example, if the lamp is a gas discharge lamp and the device is therefore an electronic ballast, the gas discharge lamp may be switched off by switching off the inverter in the electronic ballast.

The powerline modulator may have a switch pre-switched, whereby the powerline modulator gives a power-off command to the DC output circuit in the form of a powerline control command when the pre-switched switch is moved to its off position.

On the DC output circuit, signals can also be transmitted bidirectionally according to the Powerline technique, so that signals can also be transmitted from an operating device to the central rectifier/PFC unit.

For example, error and/or status messages can be transmitted from an operating device to the central rectifier/PFC unit or to another point connected to the DC output circuit that has a powerline demodulator.

The powerline modulator may be provided separately (externally) to the central rectifier/PFC unit and transmit signals relating to the operating status of a light source or associated device to the rectifier/PFC unit.

The control commands may be individually addressable to operational devices and/or groups of operational devices by having an address header or by assigning an individual output circuit to the operational device (s) to be addressed, in the latter case the addressing is thus done by addressing the output circuit to which the operational device to be addressed is assigned.

Individual lamps and/or groups of lamps can thus be individually started and/or dimmed by means of the Powerline control commands.

The powerline control commands can be modulated at an amplitude of less than 10%, in particular less than 5% of the DC voltage.

Moreover, it should be noted that the requirements in the Powerline DC bus can be defined without taking into account the requirements of network operators, so that the strict limitations of Powerline technology, such as those prevailing in public networks, do not have to be respected.

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A powerline modulator may be provided in the DC output circuit itself or in the central unit.

The power line demodulator in an operational device may be designed to cause the light source to be switched off on a power-off command received from the DC output circuit.

Further features, advantages and properties of the present invention are now explained in more detail by reference to the figures in the accompanying drawings and the following detailed description of an example of an embodiment. Figure 1 shows a schematic view of a control system according to the invention for luminaire control devices with central rectifier/PFC unit and DC output circuit,Figure 2 shows a state-of-the-art control device design for gas discharge lamps,Figure 3 shows a first embodiment of the present invention where Powerline control signals are modulated onto a DC output circuit, andFigure 4 shows another embodiment specifically designed for bidirectional communication between local control devices and the central unit.

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This DC output circuit has the advantage of being less susceptible to parasitic effects compared to corresponding AC circuits.

The DC output circuit 11 and 12 may be connected to emergency light control units 7 and further control units 8 respectively, which may also read signals from the connected operating equipment from the DC bus if they have a powerline demodulator.

It is therefore to be noted that, according to the present invention, the central unit is intended for several operational devices in common, the central unit being connected to the operational devices by at least one DC output circuit.

For example, as shown in Figure 1, the DC output circuit 11 is strictly separate from the mains voltage 9, so a powerline modulation for the DC output circuit 11 which is not subject to the constraints normally present in mains voltage supply can be provided, as explained in detail below.

Figure 3 shows a technique by which the DC bus can be used to supply voltage to the operating equipment 1 in a simple way, as well as to control it. According to this aspect, powerline control signals are modulated at high frequency on the DC bus 11. The hub of modulation can be, for example, 10 volts at 400 volts DC voltage.

The modulation frequency may be in the MHz range, for example.

Separately from or integrated with the central unit 20 (symbolized by reference symbol 19) a powerline PLC modulator 17 is provided to modulate control signals 23 fed from a superior control to the DC bus 11.

The parent control may be e.g. a DALI (Digital Adressable Light Interface) control.

These control signals 23 may be complex control signals to start, turn on and/or dim, etc., the light source 14 connected to the corresponding operating device 1, but in particular the PLC modulator 17 may also be pre-loaded with a simple, manually operated switch or switch 18 so that the transfer of this switch 18 to the off position is converted from the PLC modulator 17 to a powerline control signal for the DC bus 11.

This powerline control signal is then read, evaluated by a PLC modulator 15 and transmitted to a local control unit 16 in the control unit 1. The local control unit 16 ensures that the read powerline control signals are converted into a corresponding operating condition setting signal for the connected lamps 14. The control signal can therefore be used to turn a lamp on, off and/or dim or to query the status of an operating device from the central unit (master/slave zipper).

To address such a PLC command transmitted by the bus to one or a group of control devices, a powerline control command may be provided with an address header so that the PLC demodulator 15 or the connected local control unit 16 can detect whether the respective powerline control command is intended for the associated control device 1, and the control device is, of course, assigned a pre-set address stored in the control device and known to the unit sending the control command.

Alternatively or additionally, however, the central unit 20 or the associated PLC modulator 17 may also address a powerline control unit 1 by means of a powerline control command by using a DC bus line 11 assigned to that powerline control unit 1 to transmit the corresponding powerline control command. In particular, in this case, the central unit 20 may address several output circuits 11, 12 (see Fig. 1) in order to address different power lines or groups of power lines (e.g. switching on, switching off, dimming of the assigned light sources).

Figure 4 shows that a sub-unit 20 may be provided between the central unit 20 and one or more operational units 1 and may contain the PLC modulator 17.

Whereas a DC bus is provided for the distance between sub-unit 20 and an operational device, an alternating voltage (AC intermediate voltage) may be provided between sub-unit 20 and the central unit.

In addition, the design of Fig. 4 and Fig. 1 and Fig. 3 may provide for communication to DC bus 11 to be bidirectional, i.e. not only can powerline control commands be transmitted from a central 19 to local controllers 1, but also, for example, error messages and/or status signals from local controllers can be returned to central 19. In this case, the corresponding operating device 1 naturally has not only a PLC demodulator 15 but also a PLC modulator (not shown in figures) for modulating the feedback signals to DC bus 11.

Claims (21)

1. Method for controlling lamp operating devices by means of a central rectifier/PFC unit (2, 10) which is supplied with alternating voltage and which supplies a number of lamp operating devices (1) by means of at least one DC output circuit (11), the DC output circuit (11) being separated from the mains supply voltage (9) and digital radio-frequency control signals being modulated onto the DC supply voltage in a power line technique (17), which signals are read out by power line demodulators (15) in the operating devices (1) and evaluated for controlling the associated lamp (5).
2. Method according to Claim 1, a power line modulator (17) being provided in a manner separate from the central rectifier/PFC unit (2, 10) or integral with the latter (19), which modulator modulates control signals (23) supplied from a superordinate controller onto the DC bus (11).
3. Method according to Claim 1 or 2, characterized in that, in the DC output circuit or in the rectifier/PFC unit (2, 10), a power line modulator is provided to modulate supplied control signals onto the DC output circuit.
4. Method according to one of the preceding claims, characterized in that in the DC output circuit, signals are transmitted bidirectionally in power line technique in order to transmit signals from an operating device to the central rectifier/PFC unit.
5. Method according to Claim 4, characterized in that error and/or status messages are transmitted from an operating device to the rectifier/PFC unit.
6. Method according to one of the preceding claims, wherein the power line modulator is provided separately from the central rectifier/PFC unit and conveys signals with respect to the operating state of a lamp or of the associated operating means to the rectifier/PFC unit.
7. Method according to one of the preceding claims, characterized in that the control commands can be addressed individually to operating devices and/or groups of operating devices in that the commands have an address header or an individual output circuit is in each case allocated to the operating device/devices to be addressed.
8. Method according to Claim 7, characterized in that individual lamps and/or groups of lamps are started and/or dimmed individually by means of the power line control commands.
9. Method according to one of the preceding claims, characterized in that the power line control signals are modulated with an amplitude of less than 10%, especially less than 5% of the DC voltage.
10. Control system for lamp operating devices, having a central rectifier/PFC unit which is supplied with alternating voltage and which supplies a number of lamp operating devices by means of at least one DC output circuit, the DC output circuit being separated from the mains supply voltage (9) and digital radio-frequency control signals being modulated onto the DC supply voltage in a power line technique, which signals are read out by power line demodulators in the operating devices, and evaluated for controlling the associated lamps.
11. Control system according to Claim 10, a power line modulator (17) being provided in a manner separate from the central rectifier/PFC unit (2, 10) or integral with the latter (19), which modulator modulates control signals (23) supplied from a superordinate controller onto the DC bus (11).
12. Control system according to one of Claims 10 to 11, characterized in that the power line demodulator is designed for initiating new switching-off of the associated lamp following a switch-off command.
13. Control system according to one of Claims 10 to 12, characterized in that the lamp is a gas discharge lamp and the operating device is an electronic ballast, the gas discharge lamp being disconnectable by switching off an inverter in the ballast.
14. Control system according to one of Claims 10 to 13, characterized in that the power line modulator is preceded by a switch, the power line modulator delivering a switching-off command to the output circuit when the switch is brought into an off position.
15. Control system according to one of Claims 10 to 14, characterized in that the DC output circuit, the central rectifier/PFC unit and the power line demodulator are designed for a bidirectional transmission in power line technique in order to transmit signals from an operating device to the central rectifier/PFC unit.
16. Control system according to Claim 15, characterized in that error and/or status messages can be transmitted from an operating device to the rectifier/PFC unit.
17. Control system according to one of Claims 10 to 16, wherein the power line modulator is provided separately from the central rectifier/PFC unit and is designed for conveying signals with respect to the operating state of a lamp or of the associated operating means to the rectifier/PFC unit.
18. Control system according to one of Claims 10 to 17, characterized in that the control commands can be addressed individually to the operating devices and/or groups of operating devices in that the control commands are provided with an address header or an individual output circuit is allocated to the operating device/devices to be addressed.
19. Control system according to Claim 18, characterized in that individual lamps and/or groups of lamps can be started and/or dimmed individually by means of the power line control commands.
20. Control system according to one of Claims 10 to 19, characterized in that the modulation level is less than 10%, especially less than 5% of the DC voltage.
21. Control system according to one of Claims 10 to 20, an emergency lighting control unit (7) being connected to the DC output circuit (11).