Cooling device, in particular for cooling components housed in a switchgear cabinet, corresponding use and corresponding method

The disclosure relates to a cooling device, in particular for cooling components that are housed in a switchgear cabinet, comprising a first cooling fan for blowing air from the switchgear cabinet through a first heat exchanger, and a second cooling fan for blowing ambient air through a second heat exchanger, characterized in that the cooling device further comprises a voltage supply having a step-up and/or step-down converter, which is connected via a rectifier to a wide-range input for single-phase or multiphase AC voltage, and which charges a capacitor to a DC link voltage which is higher or lower than a mains voltage across the wide-range input, a power supply unit of at least one of the two cooling fans being connected in parallel to the capacitor. The disclosure further relates to the use of such a cooling device and to a corresponding method for operating the cooling device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 U.S. National Stage of International Application No. PCT/DE2015/100226, filed on Jun. 5, 2015, which claims priority to German Application No. 10 2014 107 931.0, filed on Jun. 5, 2014. The entire disclosures of the above applications are incorporated herein by reference.

FIELD

The disclosure relates to a cooling device, in particular for cooling components that are housed in a switchgear cabinet, and to a corresponding use and a corresponding method. A generic cooling device comprises a first cooling fan for blowing air from the switchgear cabinet through a first heat exchanger, and a second cooling fan for blowing ambient air through a second heat exchanger.

BACKGROUND

The prior art contains known cooling devices of this type in which the electrical components are adapted, in terms of the voltage they require to operate, to the electric mains voltages predominating in the geographic region where the cooling device will be used. Thus it is customary, for example, for a variant of each power stage of a cooling device to be offered for each of the mains voltages 115 V, 230 V and 400 V, to enable the cooling device to be marketed worldwide wherever possible. In addition to the above, various special voltages must also be considered.

The prior art therefore contains known cooling devices in which, depending on the anticipated mains voltage, for example, a suitable transformer having a primary input of 115 V, 200 V, 230 V, 400 V or 460 V is used, which then supplies a secondary output voltage of 230 V, 400 V or 460 V, depending on the primary input voltage, at various power levels. Depending on the secondary output voltage of the transformer, the cooling device has a controller which operates at the secondary output voltage of the transformer and uses corresponding voltages to control the controllable electrical components of the cooling device, in particular the cooling fans, and, if present, a compressor, the sensor system or an expansion valve. This in turn requires these cooling device components that are controlled by the controller to also be supplied in 150 V, 200 V, 230 V, 400 V or 460 V variants, depending on the geographic region where the cooling device will be used and the predominant mains voltage supplied there. In still other prior art cooling devices, the active cooling device components are powered by an adapted voltage via a transformer.

SUMMARY

It is therefore the object of the disclosure to propose a generic cooling device in which a single variant is sufficient for operating with different input AC voltages.

The cooling device according to the disclosure is characterized in that it further comprises a voltage supply with a step-up and/or step-down converter, which is connected via a rectifier to a wide-range input for single-phase or multiphase AC voltage, and which charges a capacitor to a DC link voltage which is higher or lower than a mains voltage across the wide-range input, a power supply unit of at least one of the two cooling fans being connected in parallel to the capacitor.

In a simplest embodiment, each of the first and second heat exchangers of the cooling device is an air/coolant heat exchanger, through which a liquid coolant is circulated by means of a pump. Alternatively, the cooling device may comprise a compressor-driven cooling circuit, in which case it further comprises a compressor and a choking element, for example, an expansion valve. In this embodiment, the cooling device may comprise a three-phase inverter, which is connected in parallel to the capacitor and supplies a three-phase current to the compressor. The device may also be a re-cooling device, for example a chiller.

The voltage supply for condensate management in the cooling device may particularly preferably comprise a heating element terminal for an electric heating element which is controlled via a controller, said terminal being connected in parallel to the capacitor. Thus in the cooling device according to the disclosure, such a heating element may also be formed as a single-voltage device that does not itself require multi-voltage capability.

The disclosure is therefore based on the concept of designing active components of the cooling device, in particular the cooling fans, as direct current devices, and converting any input AC voltages (single-phase or three-phase, 100 V-460 V, 50 Hz or 60 Hz) to a DC voltage suitable for operating these active cooling device components. A three-phase current that may be required for a compressor or the like is supplied by a three-phase inverter and is converted from the DC link voltage. Thus with the cooling device according to the disclosure it is no longer necessary to provide multiple variants in which the operating voltages of the active components of the cooling device are adapted to the mains voltage or to a voltage to which the mains voltage can be transformed.

In one embodiment of the disclosure, the cooling device has a mains filter for increasing interference immunity and decreasing interference output, the mains filter being connected to at least one outer conductor, one grounding conductor and optionally one neutral conductor of the wide-range input, and the grounding conductor leading from the wide-range input through the mains filter and from there directly to a three-phase output, to which the three-phase current for the compressor is supplied.

To vary the cooling power of a compressor-driven cooling device, in one embodiment of the disclosure it is provided that the three-phase inverter is controlled by an inverter controller such that the three-phase current is supplied by the three-phase inverter at the three-phase power necessary to achieve a given compressor output level.

In yet another embodiment, the step-up and/or step-down converter is controlled via a converter controller in such a way that the step-up and/or step-down converter charges the capacitor to a DC link voltage, the dimensions of which are such that the power supply voltage required to operate the first or the second cooling fan is supplied via the power supply unit. The wide-range input for single-phase or three-phase AC voltage is preferably designed at least for input voltages of between 110 V and 240 V and/or between 380 and 460V.

In yet another embodiment, the compressor and/or the cooling fans have BLDC motors.

According to another aspect, the disclosure relates to the use of a cooling device of the type described above in order to charge the capacitor via the step-up converter, irrespective of a single-phase or multiphase input AC voltage across the wide-range input, to a DC link voltage, the dimensions of which are such that the power supply voltage required to achieve a given cooling fan power of the first and/or second cooling fan is supplied via the power supply unit.

According to another aspect of the disclosure, in a cooling device having a compressor-driven cooling circuit, in order to operate the compressor at the nominal three-phase voltage necessary to achieve a required compressor output level, irrespective of a single-phase or multiphase input AC voltage across the wide-range input, the use of a cooling device of the type described above is proposed in which, for varying the output of the compressor, the three-phase inverter is designed to raise or lower a nominal three-phase voltage based on the compressor output level that is required.

According to yet another aspect, the disclosure relates to a method for operating a cooling device of the type described above, the method comprising the following steps:rectifying and raising and/or lowering a single-phase or multiphase input AC voltage between 110 V and 460 V to a constant DC link voltage and supplying the DC link voltage to a power supply unit of the cooling fan or cooling fans, the dimensions of the DC link voltage being such that the power supply unit is able to supply the power supply voltage required to operate the first and/or second cooling fan.

In one embodiment, the method further comprises the following steps:feeding the DC link voltage to the three-phase inverter;determining the required compressor output level; andadjusting the compressor-based nominal three-phase voltage that has been converted by the three-phase inverter until the required compressor output level is achieved.

DETAILED DESCRIPTION

For purposes of simplification, the FIGURE shows only a block diagram of the voltage supply1for the cooling device according to the disclosure. Voltage supply1has a wide-range input4for an up to three-phase AC voltage or a DC voltage. A grounding conductor terminal may also be provided. To increase interference immunity and decrease interference output, wide-range input4is connected to a mains filter8. Mains filter8has a three-phase output, which is connected to an input of a rectifier3designed as a rectifier bridge. Rectifier3generates a DC voltage which is fed to the step-up and/or step-down converter2. From the DC voltage that is supplied via rectifier3, step-up and/or step-down converter2generates a constant DC link voltage of 380 V, for example, which is higher or lower than the voltage supplied by the rectifier depending on the output voltage, and charges a capacitor5with said DC link voltage. The DC link voltage is fed to a power supply unit for the cooling fans20,30, which is connected in parallel to capacitor5. Step-up and/or step-down converter2is preferably a combined step-up and step-down converter.

Step-up and/or step-down converter2is controlled by a converter controller11, with controller11being designed to control step-up and/or step-down converter2so as to charge capacitor5with a constant electrical voltage, irrespective of the voltage across the wide-range input4.

The DC link voltage is fed to a three-phase inverter7, which is controlled by an inverter controller10. Inverter controller10is designed to control three-phase inverter7such that three-phase inverter7supplies the three-phase current at the three-phase power necessary to achieve a given compressor output level. The three-phase current generated by three-phase inverter7is supplied to compressor9via a three-phase output.

For condensate management, voltage supply1may further comprise a terminal12for a heating element, with the capacitor voltage of 380 V, for example, being applied across terminal12. The heating element can be controlled via a controller (not shown) for as-needed operation.

The features of the disclosure disclosed in the foregoing description, in the drawings and in the claims may be considered essential both individually and in any combination to the implementation of the disclosure.