Functional control in an uninterruptible power supply

Abstract

M1.1 Procedure for checking the functionality of an uninterruptible power supply (UPS,100), M1.2 which comprises as components a filter (21) connected to a power grid, a rectifier (22), wherein an output of the filter (21) leads to an input of the rectifier (22), an inverter (24), wherein an output of the rectifier (22) is connected to an input of the inverter (24), and a battery and / or a battery interface (23) which is connected in parallel to a DC bus between the rectifier (22) and the inverter (24), M1.3 wherein an output of the inverter (24) is connected to a bypass switch (25), via which, in a first position of the bypass switch (25), the output of the inverter (24) can be fed in a secured converter operation to a load (40) connected to the bypass switch (25), M1.4 wherein the bypass switch (25) is also connected to the power grid, so that in a second position of the bypass switch (25) a mains voltage (30) can be supplied directly to the load (40), and M1.5 wherein the uninterruptible power supply (UPS,100) includes a diagnostic module (10) having access to the components to perform a diagnostic procedure in which: M1.6 during start-up of the uninterruptible power supply (UPS,100) a) the bypass switch (25) is switched so that the mains voltage (30) is supplied directly to the load (40) and the components (21, 22, 23, 24) of the uninterruptible power supply (USV,100) are decoupled from the load (40), and M1.7 b) in parallel, the mains voltage (30) is supplied to the components (21, 22, 23, 24) of the uninterruptible power supply (UPS,100) and their function is monitored without these components (21, 22, 23, 24) being connected to the load (40) on the output side.

Description

[0001] The invention relates to a method for functional control in an uninterruptible power supply (UPS) and to a UPS with a correspondingly configured diagnostic module.

[0002] Uninterruptible power supplies are used to protect sensitive or important electrical and electronic devices such as computers from interference from the power grid, especially from a complete power failure.

[0003] US Pat. No. 5,612,580 B discloses an uninterruptible power supply (UPS) comprising a filter, rectifier, inverter, battery, and processor for controlling the UPS functions and executing a self-test routine. The UPS has a bypass function in the form of a manual bypass switch and an automatic bypass switch. When activated, each of these directly connects a load connected to the UPS to the mains power and disconnects all UPS components from the load, for example, to replace a battery. A self-test function of the UPS is described as a prerequisite for connecting the mains power to the load connected to the UPS by activating a system switch and a transfer switch. This self-test function of the UPS is executed by the processor as part of a boot-up routine when connected to the mains voltage.

[0004] The object of the present invention was to increase the functional reliability of a UPS.

[0005] This object is achieved by a method having the features of claim 1 and a UPS having the features of claim 2. Advantageous embodiments are contained in the subclaims.

[0006] The method according to the invention serves to check the function of an uninterruptible power supply (UPS) during start-up and includes the following steps: a) The mains voltage from the (public) power grid is supplied to the load to be operated. This occurs directly, i.e., without the interposition of the essential UPS components required for battery operation during a power outage. If necessary, subordinate UPS components, such as filters and / or a transfer switch, may be involved in this step. b) In parallel to step a) above, the mains voltage is supplied to the (essential) components of the UPS and their function is monitored without them being connected to the load on the output side.

[0007] This procedure has the advantage that the functionality of all components can be checked and ensured before prolonged UPS operation without the corresponding procedures affecting the load being operated. At the same time, all checks are carried out under realistic conditions, as the actual mains voltage is applied to the components being tested.

[0008] The invention further relates to an uninterruptible power supply (UPS) with a diagnostic module which is designed to carry out a method of the type described above.

[0009] The UPS controlled according to the invention can preferably include a bypass switch that can be used to switch between direct mains operation of a load and secured converter operation of the load. Such a bypass switch can then be used during the functional test to directly route the mains voltage to the load and to decouple the UPS components from the load.

[0010] The components of the UPS controlled by the method according to the invention can in particular comprise a control module for the entire UPS, a rectifier, an inverter, a battery and / or a battery interface.

[0011] The invention is explained in more detail below with the aid of the figure. The only Fig. 1 schematically shows the components of an uninterruptible power supply (UPS) 100 according to the invention.

[0012] The UPS 100 is used to protect the operation of a load 40 from a power grid 30 against grid disturbances. For this purpose, the UPS 100 is connected to the grid on the input side via a filter 21. The output side of the filter leads to the input of a rectifier 22, whose output is in turn connected to the input of an inverter 24. The output of the inverter 24 can optionally be fed to the load 40 via a bypass switch 25. In the alternative setting of the bypass switch 25, however, the grid voltage 30 is fed directly to the load. The UPS 100 also contains a battery with a battery interface 23, which is connected in parallel to the DC bus between the rectifier 22 and the inverter 24.

[0013] Furthermore, the UPS 100 contains a diagnostic module 10, which has access to all components in order to carry out the diagnostic procedure described in more detail below.

[0014] The aforementioned procedure involves self-diagnosis during startup of the UPS 100, ensuring that all system components are activated at least once before the entire system goes into operation. Particularly in the case of a double conversion or multimode UPS, the load 40 is typically started via a manual bypass (switch 25). This means that the input of the UPS 100 is also powered up by connecting it to the mains voltage 30, but the output of the converters is not yet connected to the system output. Internal checks and test cycles can therefore be performed internally using the control module (not shown), the rectifier 22, the inverter 24, and the battery interface 23.Furthermore, a portion of the system can be run at full load, with energy from the rectifier input being shifted back to the line via the DC bus, the inverter 24, and a switch (reserve static switch, not shown). If the battery is connected, the battery and the battery interface 23 can also be included in this test.

[0015] The sequence and combination of tests ensure that no hidden defects emerge during further commissioning and operation of the system. Because the self-tests are performed in a specific order, a problem can be pinpointed almost down to the level of a single component. This simplifies the process for maintenance engineers when troubleshooting faults. Another important aspect is that no additional hardware, either inside or outside the standard systems, is required to perform the described tests.

Claims

[1] M1.1 Procedure for checking the functionality of an uninterruptible power supply (UPS,100), M1.2 which comprises as components a filter (21) connected to a power grid, a rectifier (22), wherein an output of the filter (21) leads to an input of the rectifier (22), an inverter (24), wherein an output of the rectifier (22) is connected to an input of the inverter (24), and a battery and / or a battery interface (23) which is connected in parallel to a DC bus between the rectifier (22) and the inverter (24), M1.3 wherein an output of the inverter (24) is connected to a bypass switch (25), via which, in a first position of the bypass switch (25), the output of the inverter (24) can be fed in a secured converter operation to a load (40) connected to the bypass switch (25), M1.4 wherein the bypass switch (25) is also connected to the power grid, so that in a second position of the bypass switch (25) a mains voltage (30) can be supplied directly to the load (40), and M1.5 wherein the uninterruptible power supply (UPS,100) includes a diagnostic module (10) having access to the components to perform a diagnostic procedure in which: M1.6 during start-up of the uninterruptible power supply (UPS,100) a) the bypass switch (25) is switched so that the mains voltage (30) is supplied directly to the load (40) and the components (21, 22, 23, 24) of the uninterruptible power supply (USV,100) are decoupled from the load (40), and M1.7 b) in parallel, the mains voltage (30) is supplied to the components (21, 22, 23, 24) of the uninterruptible power supply (UPS,100) and their function is monitored without these components (21, 22, 23, 24) being connected to the load (40) on the output side. [2] M2.1 Uninterruptible Power Supply (UPS,100), M2.2 which comprises as components a filter (21) connected to a power grid, a rectifier (22), wherein an output of the filter (21) leads to an input of the rectifier (22), an inverter (24), wherein an output of the rectifier (22) is connected to an input of the inverter (24), and a battery and / or a battery interface (23) which is connected in parallel to a DC bus between the rectifier (22) and the inverter (24), M2.3 wherein an output of the inverter (24) is connected to a bypass switch (25), via which, in a first position of the bypass switch (25), the output of the inverter (24) can be fed in a secured converter operation to a load (40) connected to the bypass switch (25), M2.4 wherein the bypass switch (25) is also connected to the power grid, so that in a second position of the bypass switch (25) a mains voltage (30) can be supplied directly to the load (40), and M2.5 wherein the uninterruptible power supply (UPS,100) includes a diagnostic module (10) having access to the components and being configured to carry out a diagnostic procedure in which: M2.6 during start-up of the uninterruptible power supply (UPS,100) a) the bypass switch (25) is switched so that the mains voltage (30) is supplied directly to the load (40) and the components (21, 22, 23, 24) of the uninterruptible power supply (USV,100) are decoupled from the load (40), and M2.7 b) in parallel, the mains voltage (30) is supplied to the components (21, 22, 23, 24) of the uninterruptible power supply (UPS,100) and their function is monitored without these components (21, 22, 23, 24) being connected to the load (40) on the output side.

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