Power conversion system

Abstract

The present disclosure relates to a power conversion system. The power conversion system comprises a container, and multi- ple power converter modules arranged inside a first compartment of the container. The power conversion system comprises a transformer module arranged inside a second compartment of the container, wherein the second compartment is spatially separate from the first compartment. The transformer module comprises a first side and a second side and the transformer module is configured to transform a voltage at the first side to a voltage of a lower or higher level at the second side. The multiple power converter modules are configured to electrically feed the first side of the transformer module.

Description

[0001] POWER CONVERSION SYSTEM

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a power conversion system.

[0004] BACKGROUND

[0005] Nowadays, photovoltaic (PV) is used to provide electrical energy in an environmentally friendly way. In order for the electrical energy provided by a PV system to be fed to the electrical grid electrical circuits for power conversion in the form of a power conversion system may be used. For providing electrical energy using PV multiple PV modules may be employed. They may be installed on the top of buildings (e.g. the roof). This is especially advantageous in an urban environment. In such cases the power conversion system may also be installed on the top of the respective building.

[0006] SUMMARY

[0007] Providing a power conversion system may cause an effort with regard to installing and transporting such a system when setting up or changing a PV system. This has an impact on the costs of using the PV system for providing electrical energy.

[0008] One possible way to set up a power conversion system is to provide multiple inverters electrically connected to the multiple PV modules of the PV system for converting DC power of the PV system to AC power. Herein, the term “electrically connect” may be abbreviated by “connect”. The multiple inverters may be multiple string inverters. The multiple inverters may feed via cabling a power distribution and circuit protection system. The power distribution and circuit protection system may be arranged inside a first compartment of a container that is spatially separated from a second compartment of the container, in which a transformer may be arranged. The transformer may feed the electrical grid. The transformer provides a galvanic isolation from the electrical grid. The power distribution and circuit protection system may comprise multiple components, such as molded case circuit breakers (MCCBs), air circuit breakers (ACB) etc. The first compartment may represent a low voltage (LV) section of the container and the second compartment may represent a medium voltage (MV) section of the container. For example, a LV may be an AC voltage that is smaller than 1000 V AC or a DC voltage that is smaller than 1500 V DC. For example, a MV may be an AC voltage in a range between 1 kV AC and 35 kV AC. The multiple different components, such as the inverters, cables, MCCBs and ACBs have a negative effect on costs with regard to transportation and installation. Inverters, such as string inverters, gradually face growth limits while approaching power levels of hundreds of kW and weights of 150 kg and more, which cannot be handle by two or more people installing such power conversion system.

[0009] As a result of the inverters being arranged outside the container, three cables per inverter are used for electrically connecting the inverters to the electrical components of the container. This cabling is relatively long. Because cabling is long and power is crowding inside the first compartment of the container, lots of individual and common overcurrent protection devices are needed to be installed in the first compartment of the container. The first compartment of the container may be referred to as low voltage (LV) room. This LV room area occupies a significant part of the container, which is about of the volume of the container. On top of that, the cost for all the current over protection components in the first compartment is considerably high. Further, there is additional power loss within the power distribution and circuit protection system, which has a negative effect on efficiency and requires extra cooling equipment, which increases the cost further. In view of the above, this disclosure aims to provide an improved power conversion system. An objective of this disclosure is to provide a power conversion system that is improved with regard to costs. Another objective of this disclosure is to provide an improved power conversion system for providing electrical energy from a PV system to the electrical grid.

[0010] These and other objectives are achieved by the solution of this disclosure as described in the independent claims. Advantageous implementations are further defined in the dependent claims.

[0011] A first aspect of this disclosure provides a power conversion system. The power conversion system comprises a container, and multiple power converter modules arranged inside a first compartment of the container. The power conversion system comprises a transformer module arranged inside a second compartment of the container, wherein the second compartment is spatially separate from the first compartment. The transformer module comprises a first side and a second side and the transformer module is configured to transform a voltage at the first side to a voltage of a lower or higher level at the second side. The multiple power converter modules are configured to electrically feed the first side of the transformer module.

[0012] In other words, the first aspect proposes using multiple power converter modules that are arranged inside the first compartment instead of using multiple external power converter modules, such as multiple inverters, outside the container and a power distribution and circuit protection system inside the first compartment of the container. This reduces costs and installation effort as there is no need of providing in addition to multiple external power converters modules a power distribution and circuit protection system. In particular this allows omitting power distribution and circuit protection components such as MCCBs, ACBs etc.

[0013] For omitting the multiple external inverters (i.e. external power converter modules), it may be sufficient to replace each inverter by a DC combiner for feeding the multiple power converter modules of the first compartment of the container of the power conversion system according to the first aspect. For this, a DC cabling with only two cables may be used to electrically connect a respective electrical energy source, such as a DC combiner, to the multiple power converter modules of the first compartment of the container. This reduces the amount of cabling compared to the AC cabling with three cables for electrically connecting an external inverter to a power distribution and circuit protection system, which is replaced in the power conversion system of the first aspect by the multiple power converter modules.

[0014] The first aspect proposes providing all the power conversion components inside the container, instead of having external inverters and a power distribution and circuit protection system inside the first compartment of the container. This improves installation of the power conversion system, e.g. when used for converting DC power of a PV system to AC power to be fed to the electrical grid. This reduces costs for installation and transport.

[0015] The multiple power converter modules may be configured to convert DC power to AC power. This allows converting the DC power of a PV system to AC power and feed the AC power via the transformer module of the second compartment of the container to the electrical grid.

[0016] The first compartment may be a low voltage (LV) compartment. The second compartment may be a medium voltage (MV) compartment. The term “section” may be used as a synonym for the term “compartment”. The multiple power converter modules are configured to be fed by one or more electrical energy sources. In some embodiments each of the power converter modules is configured to be fed by one or more electrical energy sources. The one or more electrical energy sources may be uni- or bidirectional energy source(s). The one or more electrical energy sources may be one or more AC sources and / or one or more DC sources. For example, the one or more electrical energy sources may be at least one of one or more photovoltaic generators, one or more battery systems etc. Optionally, the one or more electrical energy sources may be one or more DC combiners, wherein each DC combiner combines DC power of two or more PV module strings. Optionally, each power converter module of the multiple power converter modules is configured to electrically feed the first side of the transformer module.

[0017] The term “feed” may be used for the term “electrically feed”. The multiple power converter modules may be configured to be bidirectional power converter modules. That is, they may be configured to be fed from the first side of the transformer module and feed one or more electrical energy sinks. The transformer module may be bidirectional. That is the first side and the second side may be an input side and output side, respectively, or vice versa. The first side and the second side of the transformer module may be galvanically isolated from each other.

[0018] The multiple power converter modules may be one or more DC to AC power converter modules and / or one or more AC to AC power converter modules. Optionally, the multiple power converter modules are multiple inverter modules. The multiple inverter modules may be bidirectional. That is, the multiple power converter modules may be multiple DC to AC power converter modules configured to convert DC to AC power. If the multiple power converter modules are bidirectional in the aforementioned optional case, they may be configured to converter AC to DC power. The terms “inverter” and “DC to AC power converter” may be used as synonyms.

[0019] For example, the voltage at the second side of the transformer module may be a voltage of higher level compared to the voltage at the first side of the transformer module.

[0020] Herein, under the term "container" any physical entity may be understood that comprises a cavity inside which components of the power conversion system may be arranged to be protected against influences from outside. The terms “enclosure” and “housing” may be used as synonyms for the term "container". The cavity comprises the first compartment and the second compartment. Optionally, the cavity may be divided in the first compartment and the second compartment.

[0021] The first compartment and the second compartment may be spatially separated from each other by a wall. The wall may be made of isolated material or may be grounded. The term “electrically grounded”, “earthed” and “electrically earthed” may be used as synonyms for the term “grounded”.

[0022] In an implementation form of the first aspect, a bus bar is arranged inside the first compartment of the container, the multiple power converter modules are electrically connected with the bus bar, and the bus bar is electrically connected with the first side of the transformer module.

[0023] The bus bar may be an AC bus bar or a DC bus bar. Since the bus bar of the first compartment and the transformer module are arranged inside the container, a length of the electrical connections between the bus bar and the first side of the transformer module is limited by the size of the container. The electrical connections may be designed robust enough to withstand elevated current levels above nominal currents. This may be correspondingly valid in case of multiple bus bars being arranged in the container.

[0024] In an implementation form of the first aspect, a power converter module of the multiple power converter modules is electrically connected with the bus bar by a respective direct pluggable electrical connection.

[0025] The aforementioned optional feature of the power converter module may be valid for more than one power converter module of the multiple power converter modules. Optionally, each power converter module of the multiple power converter modules is electrically connected with the bus bar by a respective direct pluggable electrical connection. The direct pluggable electrical connection may be a knife type connection, for example a fuse-knife contact. The term „direct pluggable connection11is used wherever (electrical) connection is made without the use of a so-called connector or connection system, which usually comprises a plug and a receptacle (counter-plug). Using direct pluggable electrical connections, such as knife type connections reduces an inspection and maintenance effort of the power conversion system.

[0026] In an implementation form of the first aspect, the first compartment of the container comprises two or more sub-compartments that are spatially separate to each other. The multiple power converter modules may be grouped into two or more groups of one or more power converter modules such that the number of the two or more groups of one or more power converter modules equals the number of the two or more sub-compartments of the first compartment of the container. Each group of the two or more groups of one or more power converter modules may be arranged inside a respective sub-compartment of the two or more sub-compartments and is configured to electrically feed a respective port of two or more ports of the first side of the transformer module. The number of the two or more ports of the first side of the transformer module equals the number of the two or more groups of one or more power converter modules.

[0027] This allows having two or more independent power conversion sections for power conversion. The two or more sub-compartments may represent multiple electrical low voltage (LV) systems.

[0028] The two or more ports of the first side of the transformer module may be galvanically isolated from each other. The two or more ports of the first side of the transformer module may be part of two or more separate electrical systems, respectively, that are galvanically isolated from each other. Each group of one or more power converter modules may be configured to feed a respective port (i.e. voltage node) of the first side of the transformer module. For example, in case the transformer module is or comprises a transformer, then the transformer may comprise for each group of the two or more groups of one or more power converter modules a primary winding at the first side and each group of one or more power converter modules may be configured to feed a respective primary winding of the transformer. In other words, in this case a port of the first side is or is electrically connected with a primary winding of the transformer at the first side.

[0029] In an implementation form of the first aspect, a bus bar is arranged inside a sub-compartment of the two or more sub-compartments, the group of one or more power converter modules of the sub-compartment of the two or more sub-compartments is electrically connected with the bus bar of the sub-compartment, and the bus bar of the sub-compartment is electrically connected to the respective port of the two or more ports of the first side of the transformer module.

[0030] The aforementioned optional feature of the sub-compartment may be valid for more than one sub-compartment of the two or more sub-compartments. Optionally, a bus bar is arranged inside each sub-compartment of the two or more sub-compartments, the group of one or more power converter modules of each sub-compartment of the two or more sub-compartments is electrically connected with the bus bar of the sub-compartment, and the bus bar of each sub-compartment is electrically connected to the respective port of the two or more ports of the first side of the transformer module. In other words, the bus bar of each sub-compartment may be electrically connected to the respective port of the two or more ports of the first side of the transformer module, which the group of one or more power converter modules of the sub-compartment is configured to electrically feed.

[0031] In an implementation form of the first aspect, a power converter module of the group of one or more power converter modules of a sub-compartment of the two or more sub-compartments is electrically connected to the bus bar of the sub-compartment by a direct pluggable electrical connection. The aforementioned optional feature of the power converter module may be valid for more than one power converter module of the group of one or more power converter modules (in case the group comprises multiple power converter modules). Optionally, each power converter module of the group of one or more power converter modules of a sub-compartment of the two or more sub-compartments is electrically connected to the bus bar of the sub-compartment by a respective direct pluggable electrical connection. The aforementioned description may be valid for each sub-compartment of the two or more subcompartments. Optionally, for at least one sub-compartment the connection to the respective bus bar may be different.

[0032] In an implementation form of the first aspect, two neighboring sub-compartments of the two or more sub-compartments are spatially separated from each other by a wall, and the wall is made of isolated material or is grounded.

[0033] This may be valid for each two neighboring sub-compartments of the two or more sub-compartments of the first compartment of the container.

[0034] In an implementation form of the first aspect, the power conversion system comprises a common cooling system for cooling the two or more sub-compartments of the first compartment of the container, and the common cooling system is grounded by a functional grounding or a protective grounding.

[0035] This allows a simultaneous cooling of the two or more sub-compartments, while ensuring a low voltage (LV) compliance (e.g. the low voltage directive (LVD) (2014 / 35 / EU) of the European Commission) by the functional ground or the protective grounding. In other words, grounding the common cooling system allows using the cooling system for the two or more subcompartments of the first compartment of the container and still maintaining an overall LV compliance. The common cooling system may be a liquid cooling system. The cooling system may comprise pipe(s), pump(s), optional radiator(s), optional re- cooler(s), optional fan(s) that are grounded by functional grounding or a protective grounding. The cooling system may be arranged at least partly in the container. The cooling system may be arranged inside the container. Optionally, at least a part of the cooling system may be arranged on a surface of the container and / or may protrude out of the container. At least a part of the cooling system may be configured to have an air exchange with an environment outside the container.

[0036] In an implementation form of the first aspect, the common cooling system is a liquid cooling system and is connected to the multiple power converter modules via spill free valves.

[0037] The liquid cooling system may comprise a conductive coolant, like at least one of water, glycol mixture and any equivalent. In case of a non-conductive coolant, such as oil or air, the connection may be implemented without the use of spill free valves, e.g. using another type(s) of valves. Using spill free valves may reduce an inspection and maintenance effort of the power conversion system compared to using another valve type.

[0038] In an implementation form of the first aspect, at least two sub-compartments of the two or more sub-compartments of the first compartment of the container comprise a door for accessing the sub-compartment from outside the container. The door of each sub-compartment of the at least two sub-compartments of the two or more sub-compartments may be configured such that among the doors of the at least two sub-compartments of the two or more sub-compartments only one door opens at any time.

[0039] This allows preventing that the electrical systems of the at least two sub-compartments are accessed at a time and, thus, allows guaranteeing a safe access into the at least two sub-compartments. Optionally, each sub-compartment of the two or more sub-compartments of the first compartment of the container comprises a door for accessing the sub-compartment from outside the container, and the door of each sub-compartment is configured such that among the doors of the two or more subcompartments only one door opens at any time.

[0040] In an implementation form of the first aspect, the first compartment of the container comprises two sub-compartments. Each sub-compartment of the two sub-compartments of the first compartment of the container may comprise a door for accessing the sub-compartment from outside the container, and the doors of the two sub-compartments may be arranged on opposite sides of the container. This allows preventing that the electrical systems of the two sub-compartments are accessed at a time (installed out of reach) and, thus, allows guaranteeing a safe access into the two sub-compartments.

[0041] In an implementation form of the first aspect, a power converter module of the multiple power converter modules comprises a load switch and / or fuse disconnector for being electrically connected to one or more electrical energy sources.

[0042] This allows providing a protection function to the power converter module for handling e.g. over currents, short circuits etc. The load switch and / or the fuse disconnector may be embedded or integrated in the power converter module (at a side for electrical connection with the one or more electrical energy sources). The aforementioned optional features of the power converter module may be valid for more than one power converter module of the multiple power converter modules. Optionally, each of the multiple power converter modules comprises a load switch and / or fuse disconnector for being electrically connected to respective one or more electrical energy sources.

[0043] In an implementation form of the first aspect, a power converter module of the multiple power converter modules comprises a load switch and / or fuse disconnector for electrically feeding the first side of the transformer module.

[0044] This allows providing a protection function to the power converter module for handling e.g. over currents, short circuits etc. The load switch and / or the fuse disconnector may be embedded or integrated in the power converter module (at the side for feeding the transformer module). The aforementioned optional features of the power converter module may be valid for more than one power converter module of the multiple power converter modules. Optionally, each of the multiple power converter modules comprises a load switch and / or fuse disconnector for feeding the first side of the transformer module.

[0045] In an implementation form of the first aspect, the container is a 20 foot ISO container or a 40 foot ISO container. For example. the container may be a 20 foot ship container or a 40 foot ship container.

[0046] In an implementation form of the first aspect, a power converter module of the multiple power converter modules is configured to be removably arranged inside the first compartment of the container by a mechanical lock / unlock system.

[0047] The aforementioned optional feature of the power converter module may be valid for more than one power converter module of the multiple power converter modules. Optionally, each power converter module of the multiple power converter modules is configured to be removably arranged inside the first compartment of the container by the mechanical lock / unlock system.

[0048] In an implementation form of the first aspect, the mechanical lock / unlock system is configured to mechanically lock and electrically turn on the power converter module, and to mechanically unlock and electrically turn off the power converter module.

[0049] In other words, when a power converter module is mechanically locked by the mechanical lock / unlock system, the power converter module is turned on. Accordingly, when the power converter module is mechanically unlocked by the mechanical lock / unlock system, the power converter module is turned off. In an implementation form of the first aspect, the transformer module comprises or is a transformer comprising one or more primary windings at the first side and a secondary winding at the second side.

[0050] The transformer may be configured to transform a voltage at a primary winding at the first side to a voltage of a lower or higher level at the secondary winding at the second side. Thus, the transformer may be configured to transform the voltage at the first side of the transformer (which may represent the voltages of the primary windings in case of multiple primary windings) to a voltage of a lower or higher level at the second side (i.e. the secondary winding) of the transformer. The first side and second side of the transformer may be referred to as “primary side” and “secondary side”, respectively. Nevertheless, the transformer may be bi-directional. The transformer may be a low voltage to medium voltage transformer (LVMV transformer). The transformer may comprise a primary winding for the group of one or more power converter modules of each sub-compartment of the first compartment of the container.

[0051] In orderto achieve the power conversion system according to the first aspect of the disclosure, some or all of the implementation forms and optional features of the first aspect, as described above, may be combined with each other.

[0052] All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof.

[0053] BRIEF DESCRIPTION OF DRAWINGS

[0054] The above described aspects and implementation forms will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which

[0055] FIG. 1 shows an example of a power conversion system according to an embodiment of this disclosure.

[0056] FIG. 2 shows an example of an implementation form of the power conversion system of FIG. 1.

[0057] FIG. 3 shows an example of an implementation form of the power conversion system of FIG. 1.

[0058] FIG. 4 shows an example of an implementation form of the power conversion system of FIG. 3.

[0059] FIG. 5 shows an example of an implementation form of the power conversion system of FIG. 4.

[0060] FIG. 6 shows an example of a cooling system that may be used in any one of the power conversion systems of

[0061] FIGs. 1 to 5.

[0062] Same elements shown in the Figures (FIGs.) are labeled with the same reference sign, and may be implemented likewise.

[0063] DETAILED DESCRIPTION OF EMBODIMENTS FIG. 1 shows an example of a power conversion system according to an embodiment of this disclosure. The power conversion system of FIG. 1 is an example of the power conversion system of the first aspect. Thus, the description of the power conversion system of the first aspect is correspondingly valid for the power conversion system of FIG. 1.

[0064] The power conversion system 1 of FIG. 1 comprises a container 2, and multiple power converter modules 3 arranged inside a first compartment 21 of the container 2. According to FIG. 1, two power converter modules 3 are arranged in the first compartment 21 of the container 2. This is only by way of example and, does not limit the present disclosure. That is, the power conversions system 1 may comprise two or more power converter modules 3 that are arranged inside the first compartment 21 of the container 2. The power conversion system 1 comprises a transformer module 4 arranged inside a second compartment 22 of the container 2, wherein the second compartment 22 is spatially separate from the first compartment 21. The transformer module 4 comprises a first side FS and a second side SS. The transformer module 4 is configured to transform a voltage VI at the first side FS to a voltage V2 of a lower or higher level at the second side SS. Optionally, the transformer module 4 comprises or is a transformer comprising one or more primary windings at the first side FS and a secondary winding at the second side SS (not shown in FIG. l).The multiple power converter modules 3 of the power conversion system 1 are configured to electrically feed the first side FS of the transformer module 4 (indicated in FIG. 1 by an arrow extending from the multiple power converter modules 3 to the transformer module 4).

[0065] Optionally, the first compartment 21 and the second compartment 22 of the container 2 are spatially separated from each other by a wall. The wall is made of isolated material or is grounded. The transformer module 4 may comprise a galvanic isolation between its first side FS and its second side SS.

[0066] For further details, such as optional features, of the power conversion system of FIG. 1 reference is made to the description of the power conversion system according to the first aspect and the description of FIGs. 2, 3, 4, 5 and 6.

[0067] FIG. 2 shows an example of an implementation form of the power conversion system of FIG. 1. The power conversion system of FIG. 2 corresponds to the power conversion system of FIG. 1. Thus, for describing the power conversion system of FIG. 2 reference is made to the description of the power conversion system of FIG. 1 and in the following mainly additional optional features of the power conversion system of FIG. 2 are described.

[0068] The power conversions system 1 of Figure 2 comprises a bus bar 5 that is arranged inside the first compartment 21 of the container 2. The multiple power converter modules 3 are electrically connected with the bus bar 5, and the bus bar 5 is electrically connected with the first side FS of the transformer module 4. Thus, the multiple power converter modules 3 are configured to electrically feed the transformer module 4 via the bus bar 5.

[0069] FIG. 3 shows an example of an implementation form of the power conversion system of FIG. 1. The power conversion system of FIG. 3 corresponds to the power conversion system of FIG. 1. Thus, for describing the power conversion system of FIG. 3 reference is made to the description of the power conversion system of FIG. 1 and in the following mainly additional optional features of the power conversion system of FIG. 3 are described.

[0070] The first compartment 21 of the container 2 of the power conversion system 1 may comprises two or more sub-compartments that are spatially separate to each other. In the example of FIG. 3 , the first compartment 21 comprises two sub-compartments 21a and 21b. This is only by way of example and not limiting for the disclosure. That is, the first compartment 21 may comprise more than two sub-compartments (not shown in Figure 3). For the following description it is assumed that the container 2 comprise two sub-compartments 21a and 21b. The following description is correspondingly valid in case the first compartment 21 comprise more than two sub-compartments. The multiple power converter modules 3 are grouped into two groups 30 of one or more power converter modules such that the number of the groups 30 of one or more power converter modules equals the number of the sub-compartments 21a, 21b of the first compartment 21 of the container 2. In the example of FIG. 3, the number of power converter modules of the groups 30 of one or more power converter modules is one. This is only by way of example and does not limit the present disclosure. The number of power converter modules of the groups 30 may be greater than one, i.e. the groups 30 may be groups 30 of multiple power converter modules. In the example of FIG. 3 the number of sub-compartments 21a, 21b of the first compartment is two and, thus, the number of the groups 30 of one or more power converter modules is also two. Each group of the two groups 30 of one or more power converter modules is arranged inside a respective sub-compartment of the two sub-compartments 21a and 21b and is configured to electrically feed a respective port of ports (indicated as small squares in FIG. 3) of the first side FS of the transformer module 4. The number of the ports of the first side FS of the transformer module 4 equals the number of the groups 30 of one or more power converter modules and, thus, the number of sub-compartments 2 la, 2 lb of the first compartment 21 of the container 2.

[0071] The sub-compartments 21a and 21b of the power conversion system 1 of FIG. 3 are neighboring to each other. They may be spatially separated from each other by a wall. The wall may be made of isolated material or may be grounded. The aforementioned may be valid for any two neighboring sub-compartments of the first compartment 21 of the container 2.

[0072] FIG. 4 shows an example of an implementation form of the power conversion system of FIG. 3. The power conversion system of FIG. 4 corresponds to the power conversion system of FIG. 3. Thus, for describing the power conversion system of FIG. 4 reference is made to the description of the power conversion system of FIG. 3 and in the following mainly additional optional features of the power conversion system of FIG. 4 are described.

[0073] As shown in FIG. 4, each sub-compartment 2 la, 2 lb of the first compartment 21 of the container 2 may comprise a group 30 of multiple power converter modules. According to the example of FIG. 4, each group 30 of multiple power converter modules comprise two power converter modules 3. This is only by way of example and does not limit this disclosure. That is, the group 30 of multiple converter modules may comprise only one power converter module or more than two power converter modules. Each power converter module 3 may be fed by an electrical energy source 40. For example, the electrical energy source 40 may be a PV module or PV module string of a PV system. Alternatively, the electrical energy source 40 may be a DC combiner that combines the DC power of multiple PV modules of the PV system.

[0074] Optionally, each power converter module 3 may comprise an embedded disconnect 6 via which it is connected to the respective electrical energy source 40. This allows providing an electrical protection. As shown in FIG. 4, a bus bar 5 may be arranged inside each sub-compartment 21a, 21b of the first compartment 21 of the container 2, wherein the group 30 of power converter modules of the sub-compartment 21a, 21b is electrically connected with the bus bar 5 of the sub-compartment 21a, 21b, and the bus bar 5 of the sub-compartment 21a, 21b is electrically connected to the respective port of the two ports of the first side FS of the transformer module 4.

[0075] The second side SS of the transformer module 4 may feed power, e.g. AC power, to the electrical grid 50. For this, the second side SS of the transformer module 4 may be electrically connected to the electrical grid 50.

[0076] FIG. 5 shows an example of an implementation form of the power conversion system of FIG. 4. The power conversion system of FIG. 5 corresponds to the power conversion system of FIG. 4. Thus, for describing the power conversion system of FIG. 5 reference is made to the description of the power conversion system of FIG. 4 and in the following mainly additional optional features of the power conversion system of FIG. 5 are described. As shown in FIG. 5, the first compartment 21 of the container 2 may be divided into two sub-compartments 21a and 21b. Each of the two sub-compartments 21a, 21b may comprise a group 30 of one or more power converter modules 3. The group 30 of one or more power converter modules 3 of a first sub-compartment 21a of the first compartment 21 of the container 2 is labelled using the letter “A”, and the group 30 of one or more power converter modules 3 of a second sub-compartment 2 lb of the first compartment 21 of the container 2is labelled using the letter “B”.

[0077] As shown in FIG. 5, the electrical energy source 40 for feeding the group A of one or more power converter modules 3 of the first sub-compartment 2 la of the first compartment 21 of the container 2 may comprise one or more DC combiners A (e.g. one or more DC combiner maximum power point tracker (MPPT) boxes) that combine DC voltages of multiple PV modules (the number of six PV modules shown in FIG. 5 is merely by way of example, and can be any number). The electrical energy source 40 for feeding the group B of one or more power converter modules 3 of the second sub-compartment 2 lb of the first compartment 21 of the container 2 may comprise one or more DC combiners B that combine DC voltages of multiple PV modules (the number of six PV modules shown in FIG. 5 is merely by way of example). Each group A, B of one or more power converter modules 3 may be electrically connected via two cables 60 to the electrical energy source 40, e.g. the respective DC combiner A or B. For example, a DC voltage of + 750 V and - 750 V may be provided to the groups A, B of one or more power converter modules 3. This voltage values, cable numbers and voltage type (DC or AC) are merely by way of example and may be different.

[0078] Optionally, each of the multiple power converter modules 3 may comprise a load switch 6 and / or a fuse disconnector 7 for being electrically connected to the electrical energy source 40, e.g. the respective DC combiner. Optionally, each of the multiple power converter modules 3 may comprise a load switch 6 and / or a fuse disconnector 7 for electrically feeding the first side FS of the transformer module 4. Optionally, the multiple power converter modules 3 may be multiple inverters. Each inverter may optionally have a single or multiple mains relay(s) 8.

[0079] As shown in FIG. 5, optionally the transformer module 4 may comprise or may be a transformer comprising a primary winding LV-A, LV-B for each sub-compartment 21a, 21b of the first compartment 21 at the first side FS and a secondary winding MV at the second side. The secondary winding MV may electrical feed AC power to the electrical grid 50.

[0080] The implementation forms of the power conversion system of FIGs. 2, 3, 4 and 5 may be combined with each other in any way. In the FIGs. 1, 2, 3, 4 and 5, the shown number of multiple power converter modules 3 of the first compartment 21 and / or the shown number of sub-compartments of the first sub-compartment 21 and / or the shown number of power converter module(s) 3 of the group 30 of one or more power converter modules are only by way of example and may be different. The description of FIGs. 1 , 2, 3 , 4 and 5 is correspondingly valid. In case the power converter modules are bi-directional, the electrical energy sources 40 in the FIGs. may represent electrical energy sinks.

[0081] FIG. 6 shows an example of a cooling system that may be used in any one of the power conversion systems of FIGs. 1 to 5.

[0082] As shown in FIG. 6, the power conversion system 1 may comprise a common cooling system 70 for cooling two or more subcompartments 21a, 21b of the first compartment 21 of the container 2. The common cooling system 70 is grounded by a functional grounding, i.e. functional earth (FE), or a protective grounding, i.e. protective earth (PE). The common cooling system 70 may be a liquid cooling system. The cooling system 70 may comprise pipe(s) 71, pump(s), optional radiator(s), optional re-cooler(s), optional fan(s) that are grounded by the functional grounding or the protective grounding. For further information on the cooling system reference is made to the description of the power conversion system of the first aspect. For further information on the examples of FIGs. 1 , 2, 3 , 4, 5 and 6 reference is made to the description of the power conversion system of the first aspect.

[0083] The power conversion system of this disclosure may be used for converting DC power of a photovoltaic (PV) system to AC power and providing the AC power to the electrical grid. In addition or alternatively, the power conversion system of this disclosure may be used for converting DC power of a battery system (e.g. rechargeable battery system) comprising one or more batteries to AC power and providing the AC power to the electrical grid.

[0084] The present disclosure has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed matter, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.

Claims

CLAIMS1. A power conversion system (1) comprising a container (2), multiple power converter modules (3) arranged inside a first compartment (21) of the container (2), and a transformer module (4) arranged inside a second compartment (22) of the container (2), the second compartment (22) being spatially separate from the first compartment (21); wherein the transformer module (4) comprises a first side (PS) and a second side (SS) and the transformer module (4) is configured to transform a voltage (VI) at the first side (PS) to a voltage (V2) of a lower or higher level at the second side (SS), and the multiple power converter modules (3) are configured to electrically feed the first side (PS) of the transformer module (4).

2. The power conversion system (1) according to claim 1, wherein a bus bar (5) is arranged inside the first compartment (21) of the container (2), the multiple power converter modules (3) are electrically connected with the bus bar (5), and the bus bar (5) is electrically connected with the first side (PS) of the transformer module (4).

3. The power conversion system (1) according to claim 1 or 2, wherein a power converter module of the multiple power converter modules (3) is electrically connected with the bus bar (5) by a respective direct pluggable electrical connection.

4. The power conversion system (1) according to claim 1, wherein the first compartment (21) of the container comprises two or more sub-compartments (2 la, 2 lb) that are spatially separate to each other, the multiple power converter modules (3) are grouped into two or more groups (30) of one or more power converter modules such that the number of the two or more groups (30) of one or more power converter modules equals the number of the two or more sub-compartments (21a, 21b) of the first compartment (21) of the container (2), and each group (30) of the two or more groups (30) of one or more power converter modules is arranged inside a respective sub-compartment of the two or more sub-compartments (21a, 21b) and is configured to electrically feed a respective port of two or more ports of the first side (PS) of the transformer module (4), the number of the two or more ports of the first side (PS) of the transformer module (4) equals the number of the two or more groups (30) of one or more power converter modules.

5. The power conversion system (1) according to claim 4, wherein a bus bar (5) is arranged inside a sub-compartment of the two or more sub-compartments (21 a, 2 lb), the group (30) of one or more power converter modules of the sub-compartment of the two or more sub-compartments (21a, 21b) is electrically connected with the bus bar (5) of the sub-compartment, and the bus bar (5) of the sub-compartment is electrically connected to the respective port of the two or more ports of the first side (PS) of the transformer module (4).

6. The power conversion system (1) according to claim 4 or 5, wherein a power converter module of the group (30) of one or more power converter modules of a sub-compartment of the two or more sub-compartments (2 la, 2 lb) is electrically connected to the bus bar (5) of the sub-compartment by a direct pluggable electrical connection.

7. The power conversion system (1) according to any one of claims 4 to 6, wherein two neighboring sub-compartments of the two or more sub-compartments (21a, 21b) are spatially separated from each other by a wall, and the wall is made of isolated material or is grounded.

8. The power conversion system (1) according to any one of claims 4 to 7, wherein the power conversion system (1) comprises a common cooling system (70) for cooling the two or more sub-compartments (21a, 21b) of the first compartment (21) of the container (2), and the common cooling system (70) is grounded by a functional grounding or a protective grounding.

9. The power conversion system (1) according to claim 8, wherein the common cooling system (70) is a liquid cooling system and is connected to the multiple power converter modules (3) via spill free valves.

10. The power conversion system (1) according to any one of claims 4 to 9, wherein at least two sub-compartments of the two or more sub-compartments (2 la, 2 lb) of the first compartment (21) of the container (2) comprise a door for accessing the sub-compartment from outside the container (2), and the door of each sub-compartment of the at least two sub-compartments of the two or more sub-compartments (21a, 2 lb) is configured such that among the doors of the at least two sub-compartments of the two or more sub-compartments (21a, 21b) only one door opens at any time.

11. The power conversion system (1) according to any one of claims 4 to 10, wherein the first compartment (21) of the container (2) comprises two sub-compartments (2 la, 2 lb), each sub-compartment of the two sub-compartments (2 la, 2 lb) of the first compartment (21) of the container (2) comprises a door for accessing the sub-compartment from outside the container (2), and the doors of the two sub-compartments (2 la, 2 lb) are arranged on opposite sides of the container (2).

12. The power conversion system (1) according to any one of the previous claims, wherein a power converter module of the multiple power converter modules (30) comprises a load switch (6) and / or fuse disconnector (7) for being electrically connected to one or more electrical energy sources (40).

13. The power conversion system (1) according to any one of the previous claims, wherein a power converter module of the multiple power converter modules (30) comprises a load switch (6) and / or fuse disconnector (7) for electrically feeding the first side (PS) of the transformer module (4).

14. The power conversion system (1) according to any one of the previous claims, wherein the container (2) is a 20 foot ISO container or a 40 foot ISO container.

15. The power conversion system (1) according to any one of the previous claims, wherein a power converter module of the multiple power converter modules (30) is configured to be removably arranged inside the first compartment (21) of the container (2) by a mechanical lock / unlock system.

16. The power conversion system (1) according to claim 15, whereinthe mechanical lock / unlock system is configured to mechanically lock and electrically turn on the power converter module, and to mechanically unlock and electrically turn off the power converter module.

17. The power conversion system (1) according to any one of the previous claims, wherein - the transformer module (4) comprises or is a transformer comprising one or more primary windings at the first side(PS) and a secondary winding at the second side (SS).

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