BUS CENTRAL UNIT WITH POWER MONITORING

Description

[0001] The present invention relates fundamentally to central units for bus systems and to bus systems comprising such a central unit.

[0002] More specifically, the invention relates to central units and bus systems in the field of building technology, wherein operating devices for lamps (e.g. LED converters) and sensors (such as light sensors, presence sensors, motion sensors, smoke detectors, etc.) are typically connected to such a bus.

[0003] The invention requires a bus protocol in which the bus is live in its idle state, allowing it to be used for power supply by connected bus devices within the framework of specified standards. An example of this is the so-called DALI bus standard.

[0004] In addition, the active bus participants, such as the operating devices for lamps, are supplied from a mains voltage supply.

[0005] WO 2009 / 121082 A1 discloses a method for controlling an operating device for lighting devices. This document already discloses that, starting from a central unit, bus devices can not only be switched on or off via the bus line, but can also be disconnected from the mains supply by a central control unit. This technology can therefore be fully adopted in the present invention.

[0006] Furthermore, approaches are known in which the voltage supply for the bus, as well as the power supply for the participants themselves, is decentralized within a bus system. The problem with this is that the frequently occurring request for power consumption measurement is difficult to fulfill.

[0007] DE 10 2014 103 524 A1 discloses a circuit arrangement for operating at least one lighting means.

[0008] The invention is described in the appended claims. The invention now proposes a central unit or a bus system with bus devices, in which, in particular, power monitoring is facilitated.

[0009] According to a first aspect of the invention, a central unit is provided for a bus system, in particular a bus system in the field of building technology and in particular lighting technology. The central unit has an input for supplying a power supply, preferably an (AC) mains power supply.

[0010] According to the invention, the central unit loops the mains voltage supplied to it to provide the power supply at an output to at least one bus node. This provides centralized power supply to the bus nodes.

[0011] Furthermore, the central unit has a unit for providing a power supply to a bus connection, thus supplying a connected bus, which preferably carries a voltage in the idle state, as is the case with a DALI bus, for example. This also provides a central power supply for the bus lines, allowing the bus lines to be used by the decentralized bus devices within a specified range (typically a maximum current level at specified bus voltage levels).

[0012] The central unit also has an interface unit for sending and receiving data via the bus connection. The bus participants can thus be addressed, preferably in an addressed manner, which can include, for example, the transmission of dimming commands in the case of operating devices for lighting. Furthermore, data can be sent back from the bus participants to the central unit, which is of course particularly, but not exclusively, the case with sensors that can therefore send back detection data via the bus line. According to the invention, a unit is also provided in the central unit which limits the starting current to a predetermined value. The starting current is the current which, in the present case, a bus participant, in particular an active bus participant such as, for example, an operating device for lighting, consumes when it is switched on again from an off state.This starting current can reach undesirably high levels, for example, because the capacitors of the bus device must be charged on the input side. This problem is particularly acute when multiple bus devices are switched on simultaneously. The starting current therefore flows at the output to loop through the power supply voltage when one or more connected bus devices are switched on.

[0013] This starting current limiting unit detects and, if necessary, limits the starting current, particularly discontinuously, namely preferably during the zero crossings of the looped mains voltages.

[0014] The central unit can be designed to allow the connected bus devices to be switched on only during specific sections of the sine waves of the looped mains voltage, particularly in the area of ​​their zero crossings, to ensure that the connected devices start up with a slower current increase. This can be achieved by switching on via a bus command and / or connecting the devices to the looped mains voltage.

[0015] The invention further relates to a central unit for a bus system of the type described above, in which a detection unit is provided that detects the electrical power consumption of all connected bus devices. This elegantly exploits the fact that, according to the invention, the power supply for the connected bus devices is centralized, and thus the power consumption, or more precisely, the total power consumption of all connected bus devices, can be detected centrally.

[0016] This total power consumption can be determined, for example, by the power consumption of the central unit by measuring the voltage and current at the power supply input of the central unit.

[0017] To obtain more precise information regarding the distribution of the recorded total power consumption among the respective connected bus devices, the central unit is designed to selectively switch on only one of several connected bus devices during a measurement phase, particularly to a predetermined power level, and then to selectively record only the power consumption of this one switched-on bus device during this measurement phase. For example, if the power consumption of an operating device for a light source at 100% dimming value is known, in a subsequent operating phase, i.e. when several operating devices are switched on, it is possible to determine how the determined total power consumption is distributed among the individual bus devices based on the current dimming values ​​of the connected bus devices known to the central unit.

[0018] In the aforementioned measurement phase, a bus device, which is an operating device for lighting, is preferably controlled to a predetermined dimming level, and in particular to the dimming value of 100%, so that the power consumption of this one bus device at the specified dimming level is known, and the power consumption at other dimming levels can be determined by extrapolation. Alternatively, however, additional reference values ​​for the power consumption of the individual bus device can also be determined, i.e., by having the central unit record power consumption not only at one dimming level, but at multiple dimming levels of the connected operating device.

[0019] The central unit is designed to switch connected bus devices on and off via bus commands, which are typically addressed. Furthermore, the central unit is preferably also designed to completely disconnect connected bus devices from the mains voltage, which has the advantage of reducing the standby power consumption of the bus devices.

[0020] The invention further relates to a bus system comprising a central unit according to one of the preceding claims and at least one connected bus device. The bus device can be, for example, an operating device for lighting devices, in particular an operating device for an LED line. Alternatively or additionally, sensors, in particular sensors known from the field of building technology, can be used.

[0021] Further features, properties and advantages of the present invention will now be explained in more detail with reference to the accompanying figure, which shows an embodiment.

[0022] In the figure you can see a central unit Z, which is a central unit in several aspects, namely: It centrally loops a mains voltage L, N to the bus participants, the bus lines D1, D2 are centrally supplied with a bus voltage.

[0023] As can be seen from the figure, bus lines D1 and D2 can be used to connect, for example, control gear for lamps D1...Dn. Sensors S1...Sn can also be connected. One possible application is to configure the bus as a DALI bus, which is an example of a bus that is live when inactive (the bus's idle state). However, bus systems that are live when active can also be used.

[0024] Thus, commands, particularly control commands such as dimming commands, can be sent to bus devices S1...Sn and D1...Dn, preferably addressed by the central unit. Furthermore, the bus is preferably bidirectional (as is the case with the DALI bus), so that devices S1...Sn and D1...Dn can also send data back to the central unit Z.

[0025] According to the invention, the central unit Z has a power supply PS and an interface IF, with the output of the interface IF being led to the terminals D1, D2 for the bus line. The power supply PS, which is powered by the mains voltage L, N, can therefore modulate a bus voltage onto the bus voltage lines D1, D2. The bus voltage supply PS can, for example, have a flyback converter. The interface circuit IF is designed, on the one hand, to transmit signals via the bus line D1, D2 by selectively short-circuiting the bus lines in the case of the DALI bus. In addition, the interface IF is of course also designed to receive commands from the bus and forward them to a control unit (not shown) provided in the central unit.The return of bus signals from the bus participants to the central unit is preferably carried out by the bus participants selectively short-circuiting the bus which is live in the idle state.

[0026] As shown in the figure, the mains voltage lines L, N are looped through in the central unit Z, so that the bus devices are centrally supplied with power through this looping. A detection and limiting unit IRL is provided for the so-called starting current. This means that when a bus voltage device, in particular an active bus device, is switched on by the central unit (i.e., by sending a command via the interface IF), the IRL unit preferably detects the current during the zero crossings of the mains voltage L, N and limits it if necessary. This allows the starting current to be limited to a specified level when one or, in particular, several active bus devices are switched on.If the IRL unit detects that the starting current reaches the maximum permissible level, it can send a message to the IF interface so that it can take countermeasures, which may include, for example, switching off or delaying the switching on of other bus devices.

[0027] Furthermore, it can also be stipulated that the switching on of bus devices, especially active, i.e., power-consuming bus devices, may only occur at specified times, namely only during the zero crossings of the mains voltage. This ensures a smoother start-up of the switched-on bus devices, i.e., with a reduced maximum level of the starting current.

[0028] This disclosure also relates to a method for operating a central unit (Z) for a bus system, comprising the following steps: Looping the power supply voltage to at least one bus device, providing a power supply at a bus connection in order to supply a connected bus which preferably does not carry any voltage in the idle state, such as a DALI bus, sending and receiving data via the bus connection, and limiting a starting current to a predetermined value, which starting current flows at the output for looping the power supply voltage when one or more connected bus devices are switched on.

[0029] Although the present invention was explained in the above embodiment based on the DALI standard, other interfaces IF can also be used, such as USB to DALI, wireless to DALI, IP to DALI, etc.

[0030] According to the invention, power consumption measurement (PM, power metering, power monitoring) is carried out centrally in the central unit.

[0031] The decentralized bus devices can be completely shut down by the central unit, including disconnecting them from the mains power supply. This is not possible with current technology where power metering is not performed centrally, since a complete shutdown is not permitted while a power meter is running.

[0032] Even if, according to the invention, the central unit can only record the total consumption of all connected bus devices during the operating phase, the preferably upstream measuring phase when commissioning an individual device at a predetermined dimming value ensures that in the actual operating phase the total power consumption can be correctly distributed among the operating devices based on the dimming values ​​known in the central unit.

Claims

1. Central unit (Z) for a bus system, comprising: - an input (L, N) for a voltage supply, preferably a mains voltage supply, and - a unit (PS) for providing a voltage supply to a bus connection in order to supply a connected bus, which preferably carries a voltage in the idle state, such as a DALI bus, characterized by - at least one output for looping the voltage supply voltage to at least one bus participant, - a detection unit that detects the electrical power consumption of all connected bus participants, and in that the central unit is designed, in a measuring phase, to selectively switch on only one of a plurality of connected bus participants and to detect the power consumption thereof, and in that when detecting the total consumption, the detection unit allocates the total consumption to the respective connected bus participants on the basis of the measurement in the measuring phase and a dimming command currently sent by the central unit via the bus to the relevant device.

2. Central unit according to claim 1, further comprising - an interface unit (IF) for sending and receiving data via the bus connection, and - a current limiting unit (IRL) which limits the starting current to a predetermined value, which starting current flows at the output for looping the voltage supply voltage when one or more connected bus participants are switched on.

3. Central unit according to claim 2, wherein the current limiting unit (IRL) detects the starting current during the zero crossings of the looped mains voltage and limits it if necessary.

4. Central unit according to claim 1, further comprising: - an interface unit (IF) for sending and receiving data via the bus connection.

5. Central unit according to any of the preceding claims, wherein the switched-on bus participant is an operating device for lamps, which is controlled by the central unit to a predetermined dimming level such as 100% during this individual measuring phase.

6. Central unit according to any of the preceding claims, wherein the detection unit detects the total consumption by means of the voltage and current at the voltage supply input of the central unit.

7. Central unit according to any of the preceding claims, which is designed to switch on and off connected bus participants via commands via the bus and to disconnect the connected bus participants from the mains voltage.

8. Central unit according to any of the preceding claims, which is designed to enable switch-on processes of connected bus participants only in certain portions of the sine waves of the looped mains voltage, in particular in the region of its zero crossings.

9. Bus system, comprising a central unit according to any of the preceding claims and at least one connected bus participant, in particular an operating device for lamps such as an LED array and / or a sensor, in particular a building technology sensor.