Electrical assembly

Abstract

There is provided an electrical assembly comprising a converter (20) for connection to an electrical network (40), the converter (20) comprising at least one module (44), the at least one module (44) comprising at least one switching element (46) and at least one energy storage device (48), the or each switching element (46) and the or each energy storage device (48) in the or each module (44) being arranged to be combinable to selectively provide a voltage source, the electrical assembly comprising a controller (54) configured to selectively control switching of the or each switching element (46) in the or each module (44), wherein the electrical assembly comprises a sensor (56a) configured for measuring a current of the electrical network (40), wherein the controller (54) and the sensor (56a) are configured to operate in coordination to perform a characterisation of an electrical parameter of the electrical network (40) such that, in use: the controller (54) selectively controls switching of the or each switching element (46) in the or each module (44) to modify an electrical parameter of the converter (20) in order to modify the current of the electrical network (40); the sensor (56a) measures the resulting modified current of the electrical network (40); and the controller (54) processes the measured resulting modified current of the electrical network (40) in order to characterise the electrical parameter of the electrical network (40).

Description

Technical Field

[0001] This invention relates to an electrical assembly comprising a converter for connection to an electrical network (preferably an AC power grid), and a method of operating the electrical assembly. The invention is preferably intended for use in high-voltage direct current (HVDC) transmission. Background Technology

[0002] In HVDC power transmission networks, alternating current (AC) power is typically converted to direct current (DC) power for transmission via overhead lines, submarine cables, and / or underground cables. This conversion eliminates the need to compensate for the AC capacitive load effect imposed by the power transmission medium (i.e., transmission lines or cables) and reduces the cost per kilometer of line and / or cable, thus becoming cost-effective when power needs to be transmitted over long distances.

[0003] The conversion between DC and AC power is used in power transmission networks where DC and AC networks must be interconnected. In any such power transmission network, a converter is required at each interface between AC and DC power to achieve the required conversion from AC to DC or from DC to AC. Summary of the Invention

[0004] According to a first aspect of the invention, an electrical assembly is provided, the electrical assembly including a converter for connection to an electrical network, the converter including at least one module, the at least one module including at least one switching element and at least one energy storage device, the switching element and the energy storage device in the module being arranged to be combinable for selectively providing a voltage source, the electrical assembly including a controller configured to selectively control the switching of the switching element in the module, wherein the electrical assembly includes a sensor configured to measure the current of the electrical network, wherein the controller and the sensor are configured to operate in coordination to perform characterization of electrical parameters of the electrical network, such that in use:

[0005] The controller selectively controls the switching of the switching element in the module to modify the electrical parameters of the converter in order to modify the current in the electrical network.

[0006] The sensor measures the resulting modified current of the electrical network; and

[0007] The controller processes the measured modified current of the electrical network to characterize the electrical parameters of the electrical network.

[0008] The configuration of the controller and sensors in the electrical assembly of the present invention results in an intelligent system that uses integrated converter hardware, in the form of said or each module, to characterize one or more electrical parameters of the connected electrical network. This provides a converter with embedded electrical network characterization capabilities, and thereby eliminates the need for separate and dedicated electrical network characterization devices (e.g., impedance analyzers).

[0009] In addition, during the characterization process, the converter or each module provides the converter with the ability to perform online characterization of the electrical network, without the converter and the electrical network having to be offline and without changing the steady-state operating conditions (e.g., active and reactive power operating points) of the converter and the electrical network.

[0010] Furthermore, it is even more advantageous to use the aforementioned module in the characterization process, not only because the characterization process is easily scalable to be compatible with converters with different ratings having different numbers of modules, but also because the number of modules used in the characterization process can be easily changed to modify the parameters of the characterization process without incurring significant costs in redesigning and building new converter structures.

[0011] In contrast, using separate and dedicated electrical network characterization equipment to characterize the electrical parameters of a connected electrical network incurs additional costs in the form of installation and operation costs, increases the overall size and weight of the converter and the electrical network, and is less easily scalable for use with converters of different ratings and for different characterization processes.

[0012] One or more electrical parameters of an electrical network (e.g., network impedance) can change due to variations in the operating conditions of the network(s). Any changes in the operating conditions of the network(s) can occur due to, for example, black start, due to selective connection and disconnection of power generation equipment, varying loads, and the energizing sequence of network equipment or components (e.g., transformers, cables, and switching devices). Changes in one or more electrical parameters of the network can lead to undesirable states of the converter and the network, such as system instability, which in turn can cause equipment damage and / or disconnection of the converter and the network by, for example, tripping.

[0013] After characterizing the electrical parameters of the electrical network, the characterized parameters can then be used by the controller to adapt the control of the converter. Therefore, the configuration of the electrical assembly of the present invention used to perform the characterization process enables the converter to adjust its operation and / or structure in real time in response to any changes in the electrical parameters of the electrical network, which is advantageous under constantly changing operating conditions of the electrical network.

[0014] In embodiments of the invention, the controller may be configured to process the characterized electrical parameters of the electrical network to control the switching of the one or more switching elements in the one or more modules, in order to adapt to the control of the converter. As a result, the one or more modules of the converter are configured to perform both the characterization process and subsequent response regulation of the control of the converter(s), thereby providing advantages in cost, size, and weight over using separate devices for performing the corresponding processes.

[0015] Preferably, the controller is configured to process the characteristic electrical parameters of the electrical network to control the switching of the switching element in the module, in order to adapt the control of the converter by performing at least one of the following:

[0016] • Modify the equivalent impedance of the converter. For example, the equivalent impedance of the converter can be modified by operating the aforementioned modules or each module to change their output voltage waveform;

[0017] • Modify the converter's control parameters;

[0018] • Provide or increase active damping for one or more oscillations in an electrical network; and

[0019] • Provides active filtering.

[0020] This adaptation of the converter's control has the following beneficial effects: it increases the stability of the converter when it is connected to an electrical network, and it increases the performance of the converter in order to meet one or more performance criteria.

[0021] In a preferred embodiment of the invention, the electrical network is an AC power grid. The invention provides a reliable apparatus for online characterization of the parameters of an AC power grid (particularly the impedance of the AC power grid).

[0022] In another embodiment of the invention, the controller may be configured to process the measured modified current of the electrical network to characterize the impedance of the electrical network. The characterized impedance provides an indication of the operating conditions of the electrical network.

[0023] In some other embodiments of the invention, the controller may be configured to process the measured modified current of the electrical network to characterize the equivalent operating voltage of the electrical network. The characterized equivalent operating voltage also provides an indication of the operating conditions of the electrical network.

[0024] The electrical parameters of the converter can be modified in a variety of different ways to alter the current of the electrical network during the characterization process.

[0025] Optionally, the controller can be configured to selectively control the switching of the switching element in the module to provide variable impedance (preferably in conjunction with an inductor) to modify the equivalent impedance of the converter, thereby modifying the current in the electrical network. The equivalent impedance of the converter can then be used to help characterize electrical parameters of the electrical network, such as impedance and equivalent operating voltage.

[0026] Alternatively, the controller can be configured to selectively control the switching of the one or each switching element in the one or each module to inject a disturbance voltage to modify the current in the electrical network, for example, by injecting at least one current component into the current in the electrical network. Preferably, the disturbance voltage can be a harmonic voltage, and the one or each injected current component can be a harmonic current component.

[0027] In this way, each module can effectively operate as a controlled source of disturbance voltage to inject each current component into the current of the electrical network. Each injected current component can then be used to help characterize electrical parameters of the electrical network, such as impedance. Specifically, the impact of disturbance voltage on the steady-state operating conditions of the converter and the electrical network can be minimized by setting the disturbance voltage level to be relatively negligible compared to the operating voltage levels of the converter and the electrical network and / or by injecting the disturbance voltage irregularly or intermittently.

[0028] In embodiments of the invention, the controller and the sensor may be configured to operate in a coordinated manner to characterize the electrical parameters of the electrical network within a frequency range.

[0029] This enables the electrical assembly of the present invention to perform comprehensive online frequency characterization of the electrical parameters of the electrical network.

[0030] In another embodiment of the invention, the converter may include at least one first module and at least one second module, wherein the controller may be configured to selectively control the switching of the one or each switching element in the one or each first module to characterize the electrical parameters of the electrical network. And wherein the controller may be configured to selectively control the switching of the one or each switching element in the one or each second module to perform the normal operating mode of the converter.

[0031] In the electrical assembly of the present invention, first and second modules are provided such that each of the first and second modules can be optimized to perform its respective function. That is, the first module can be optimized to perform a characterization process, and simultaneously the second module can be optimized to perform the normal operating mode of the converter, thereby improving the efficiency and reliability of the converter.

[0032] Examples of normal operating modes of the converter include, but are not limited to, power conversion, power transfer, and protection functions for the converter and / or the electrical network.

[0033] Additionally, each of the first modules may be configured to provide one or more additional functions, such as active power damping and filtering with increased dynamic bandwidth, electrical fault management, module redundancy, and impedance simulation under steady-state operating conditions, without interfering with the normal operating mode of the converter performed by each of the second modules.

[0034] According to a second aspect of the invention, an electrical assembly is provided, the assembly including a converter for connection to an electrical network, the converter including at least one first module and at least one second module, each of the first module and the second module including at least one switching element and at least one energy storage device, the switching element and the energy storage device in each module being arranged to be combinable to selectively provide a voltage source, the electrical assembly including a controller configured to selectively control the switching of the switching element in each module.

[0035] The controller is configured to selectively control the switching of the switching element in the second module to execute the normal operating mode of the converter.

[0036] The controller is configured to process the electrical parameters characterized by the electrical network in response to receiving them, so as to control the switching of the switching element in the first module or each of the first modules, in order to adapt to the control of the converter.

[0037] The technical benefits of the features of the electrical assembly of the second aspect of the present invention are as described above with reference to the corresponding features of the electrical assembly of the first aspect of the present invention.

[0038] Optionally, the controller of the second aspect of the invention can be configured to process the electrical parameters characterized by the electrical network in response to receiving the electrical parameters characterized by the electrical network to control the switching of the switching element in the first module, so as to adapt the control of the converter by performing at least one of the following:

[0039] • Modify the equivalent impedance of the converter;

[0040] • Modify the converter's control parameters;

[0041] • Provide or increase active damping for one or more oscillations in an electrical network;

[0042] • Provides active filtering.

[0043] In embodiments of the invention employing the first and second modules, the first module may be configured to be bypassable during the converter's normal operating mode. This improves the converter's efficiency in normal operating mode by reducing conduction losses associated with the first module.

[0044] In another embodiment of the invention employing the first and second modules, the switching element of the first module may have a higher switching frequency capability compared to the switching element of the second module.

[0045] In a preferred embodiment of the invention employing the first and second modules, the switching element of the first module may be a switching element based on a wide-bandgap material and / or the switching element of the second module may be a switching element based on a silicon semiconductor. Examples of other wide-bandgap materials include, but are not limited to, silicon carbide, boron nitride, gallium nitride, and aluminum nitride. This configuration of the switching elements of the first and second modules allows the invention to benefit from the desired properties of wide-bandgap based switching elements and / or silicon semiconductor based switching elements.

[0046] The converter can be configured such that the first module or each second module is controlled during use to perform one or more functions of the second module or each second module, and / or the second module or each second module is controlled during use to perform one or more functions of the first module or each first module. When the converter includes multiple first modules, the converter can be configured such that one, some, or all of the first modules are controlled during use to perform one or more functions of the second module or each second module. When the converter includes multiple second modules, the converter can be configured such that one, some, or all of the second modules are controlled during use to perform one or more functions of the first module or each first module.

[0047] Alternatively, the converter can be configured such that the first module and the second module are controlled during use to perform their respective functions, but neither the first module nor each second module is controlled to perform any function of the first module. That is, the first module and the second module are controlled to perform corresponding different roles within the converter operation.

[0048] In this invention, a plurality of first and second modules can be configured such that a second module comprises 70% to 99%, 75% to 95%, 80% to 90%, or 95% to 99% of the plurality of first and second modules, and said or each first module comprises 1% to 30%, 5% to 25%, 10% to 20%, or 1% to 4% of the plurality of first and second modules.

[0049] In this invention, the injected disturbance voltage can be 1%, 2%, 3%, 5%, or 10% of the converter's output voltage, or about 1%, 2%, 3%, 5%, or 10%. Therefore, the voltage rating of the first module can be set significantly lower than the voltage rating of the second module, thereby providing further savings in converter size, weight, and cost.

[0050] According to a third aspect of the invention, a method is provided for operating an electrical assembly to characterize electrical parameters of an electrical network, the electrical assembly including a converter for connection to the electrical network, the converter including at least one module, the at least one module including at least one switching element and at least one energy storage device, the at least one switching element and the at least one energy storage device in each module being arranged to be combinable to selectively provide a voltage source, wherein the method comprises the following steps:

[0051] Controlling the switching of the or each switching element in the or each module to modify the electrical parameters of the converter in order to modify the current of the electrical network;

[0052] Measure the modified current obtained from the electrical network; and

[0053] The measured modified current of the electrical network is processed to characterize the electrical parameters of the electrical network.

[0054] The features and advantages of the electrical assembly and its embodiments of the first aspect of the present invention, with necessary modifications, are applicable to the method and its embodiments of the third aspect of the present invention.

[0055] The method of the third aspect of the present invention may include the following steps: processing the electrical parameters characterized by the electrical network to control the switching of the or each switching element in the or each module, so as to adapt to the control of the converter.

[0056] The method of the third aspect of the present invention may include the following steps: processing the electrical parameters characterized by the electrical network to control the switching of the or each switching element in the or each module, so as to adapt the control of the converter by performing at least one of the following:

[0057] • Modify the equivalent impedance of the converter. For example, the equivalent impedance of the converter can be modified by operating the aforementioned modules or each module to change their output voltage waveform;

[0058] • Modify the converter's control parameters;

[0059] • Provide or increase active damping for one or more oscillations in an electrical network; and

[0060] • Provides active filtering.

[0061] In the method of the third aspect of the present invention, the electrical network may be an AC power grid.

[0062] The method of the third aspect of the present invention may include the following steps: processing the measured modified current of the electrical network in order to characterize the impedance of the electrical network.

[0063] The method of the third aspect of the present invention may include the following steps: processing the measured modified current of the electrical network in order to characterize the equivalent operating voltage of the electrical network.

[0064] The method of the third aspect of the invention may include the following steps: controlling the switching of the or each switching element in the or each module to provide variable impedance to modify the equivalent impedance of the converter in order to modify the current of the electrical network.

[0065] The method of the third aspect of the invention may include the following steps: controlling the switching of the or each switching element in the or each module to inject a disturbance voltage to modify the current of the electrical network, for example, injecting at least one current component into the current of the electrical network. Preferably, the disturbance voltage may be a harmonic voltage, and the or each injected current component may be a harmonic current component.

[0066] The method of the third aspect of the present invention may include the following steps: characterizing the electrical parameters of the electrical network within a frequency range.

[0067] In the method of the third aspect of the present invention, the converter may include at least one first module and at least one second module. The method of the third aspect of the present invention may include the following steps: controlling the switching of the one or each switching element in the one or each first module to perform characterization of the electrical parameters of the electrical network, and controlling the switching of the one or each switching element in the one or each second module to perform a normal operating mode of the converter.

[0068] According to a fourth aspect of the invention, a method is provided for operating an electrical assembly according to characterized parameters of an electrical network, the electrical assembly including a converter for connection to the electrical network, the converter including at least one first module and at least one second module, each of the first module and the second module including at least one switching element and at least one energy storage device, the switching element and the energy storage device in each module being arranged to be combinable for selectively providing a voltage source, the method comprising the following steps:

[0069] Control the switching of the or each switching element in the or each second module to perform the normal operating mode of the converter;

[0070] Receive the electrical parameters characterized by the electrical network; and

[0071] In response to receiving the electrical parameters characterized by the electrical network, the electrical parameters characterized by the electrical network are processed to control the switching of the or each switching element in the or each first module, so as to adapt to the control of the converter.

[0072] The features and advantages of the electrical assembly and its embodiments of the second aspect of the present invention, with necessary modifications, are applicable to the method and its embodiments of the fourth aspect of the present invention.

[0073] The method of the fourth aspect of the present invention may include the following steps:

[0074] In response to receiving the electrical parameters characterized by the electrical network, the electrical parameters characterized by the electrical network are processed to control the switching of the switching element in the first module, so as to adapt the control of the converter by performing at least one of the following:

[0075] • Modify the equivalent impedance of the converter;

[0076] • Modify the converter's control parameters;

[0077] • Provide or increase active damping for one or more oscillations in an electrical network;

[0078] • Provides active filtering.

[0079] The method of the second or fourth aspect of the present invention may include the following steps: bypassing the first module or each first module during the normal operation mode of the converter.

[0080] In the second or fourth aspect of the invention, using the first and second modules, the switching element of each of the first modules may have a higher switching frequency capability compared to the switching element of each of the second modules.

[0081] In the method of the second or fourth aspect of the present invention, the switching element of the first module may be a switching element based on a wide bandgap material, and / or the switching element of the second module may be a switching element based on a silicon semiconductor. Examples of other wide bandgap materials include, but are not limited to, silicon carbide, boron nitride, gallium nitride, and aluminum nitride.

[0082] The method of the second or fourth aspect of the present invention may include the following steps: controlling the or each first module to perform one or more functions of the or each second module, and / or may include the following steps: controlling the or each second module to perform one or more functions of the or each first module. When the converter includes multiple first modules, the method of the second or fourth aspect of the present invention may include the following steps: controlling one, some, or all of the first modules to perform one or more functions of the or each second module. When the converter includes multiple second modules, the method of the second or fourth aspect of the present invention may include the following steps: controlling one, some, or all of the second modules to perform one or more functions of the or each first module.

[0083] Alternatively, the method of the second or fourth aspect of the present invention may include the following steps: controlling the first module and the second module to perform their respective functions, but not controlling the first module to perform any function of the second module, and not controlling the second module to perform any function of the first module.

[0084] The configuration of each module can vary, and non-limiting examples are illustrated below.

[0085] In a first exemplary configuration of the module, the one or each switching element and the one or each energy storage device in the module can be arranged to be combined to selectively provide a unidirectional voltage source. For example, the module may include a pair of switching elements connected in parallel with the energy storage device in a half-bridge arrangement to define a two-quadrant unipolar module that can provide zero or positive voltage and can conduct current in both directions.

[0086] In a second exemplary configuration of the module, each or every switching element and each or every energy storage device in the module can be arranged to be combinable to selectively provide a bidirectional voltage source. For example, the module may include two pairs of switching elements connected in parallel with the energy storage devices in a full-bridge arrangement to define a four-quadrant bipolar module that can provide negative voltage, zero voltage, or positive voltage and can conduct current in both directions.

[0087] Multiple modules can be connected in series to define a chain link converter. The structure of the chain link converter allows for the accumulation of a combined voltage across the converter, higher than the voltage available from each of its individual modules, by inserting energy storage devices from multiple modules, each providing its own voltage, into the chain link converter. In this way, the switching of the aforementioned or each switching element in each module enables the chain link converter to provide a step-variable voltage source, which allows for the generation of voltage waveforms using a step-approximation, cross-chain link converter. Therefore, the chain link converter is capable of providing a wide range of composite voltage waveforms.

[0088] At least one switching element may include at least one self-commutating switching device. The self-commutating switching device may be an insulated-gate bipolar transistor (IGBT), a gate turn-off thyristor (GTO), a field-effect transistor (FET), a metal-oxide-semiconductor field-effect transistor (MOSFET), an injection-enhanced gate transistor (IEGT), an integrated gate-commutated thyristor (IGCT), a two-mode insulated-gate transistor (BIGT), or any other self-commutating switching device. The number of switching devices in each switching element may vary depending on the required voltage and current ratings of that switching element.

[0089] At least one switching element may further include a passive current sensing element connected in anti-parallel with the or each switching device. The or each passive current sensing element may include at least one passive current sensing device. The or each passive current sensing device may be any device capable of limiting current flow in only one direction, such as a diode. The number of passive current sensing devices in each passive current sensing element may vary depending on the required voltage and current ratings of that passive current sensing element.

[0090] Each energy storage device can be any device capable of storing and releasing energy to selectively provide voltage, such as a capacitor, fuel cell, or battery.

[0091] The converter configuration can be varied according to the power transfer requirements between the first and second networks.

[0092] In embodiments of the present invention, the converter may include at least one converter branch and a plurality of modules, said or each converter branch extending between a pair of first terminals defining a first DC terminal and a second DC terminal, said or each converter branch including a first branch portion and a second branch portion separated by a second terminal defining an AC terminal, each branch portion including at least one module among the modules.

[0093] In a preferred embodiment of the invention, the converter includes three converter branches, each of which can be connected to a corresponding phase of a three-phase AC network via a corresponding AC terminal. It will be appreciated that the converter may include different numbers of converter branches, each of which can be connected to a corresponding phase of an AC network having a corresponding number of phases via a corresponding AC terminal.

[0094] It will be understood that the use of terms such as “first” and “second” in this patent specification is intended only to help distinguish similar features (e.g., first and second modules) and not to indicate the relative importance of one feature over another, unless otherwise specified.

[0095] Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples, and alternatives set forth in the foregoing paragraphs and claims and / or the following description and drawings, and in particular their individual features, may be employed independently or in any combination. That is, all embodiments and all features of any embodiment may be combined in any manner and / or combination unless such features are incompatible. The applicant reserves the right to accordingly modify any originally filed claim or to file any new claim, including the right to modify any originally filed claim to depend on any feature of any other claim and / or incorporate any feature of any other claim, although not originally claimed in that manner. Attached Figure Description

[0096] Preferred embodiments of the invention will now be described by way of non-limiting example with reference to the accompanying drawings, in which:

[0097] Figure 1 An electrical assembly according to an embodiment of the present invention is shown;

[0098] Figure 2a and 2b Show Figure 1 The first module of the electrical assembly is a demonstration half-bridge and full-bridge chain link module configuration;

[0099] Figure 3a and 3b Show Figure 1 The second module of the electrical assembly is configured with an example half-bridge and a full-bridge chain link module.

[0100] Figure 4 The operation of the chain link module used to provide variable resistance is illustrated;

[0101] Figure 5 The equivalent circuit of the voltage source converter and AC network is shown when the chain link module is operated to provide variable impedance.

[0102] Figure 6 The operation of the chain link module as a control disturbance voltage source is shown;

[0103] Figure 7 This diagram illustrates the equivalent circuitry of the voltage source converter and AC network when the chain link module operates as a controlled disturbance voltage source within the frequency range; and

[0104] Figure 8 Shown by Figure 1 A flowchart of the characterization process performed by the electrical assembly components.

[0105] The accompanying drawings are not necessarily drawn to scale, and some features and views in the drawings are shown to scale or in schematic form for clarity and simplicity. Detailed Implementation

[0106] The following embodiments of the present invention are primarily intended for HVDC applications; however, it will be understood that the following embodiments of the present invention, with necessary modifications, can be adapted to other applications operating at different voltage levels.

[0107] The electrical assembly according to an embodiment of the present invention is in Figure 1 As shown in the figure, and generally specified by reference number 20.

[0108] The electrical assembly includes a voltage source converter 20.

[0109] The voltage source converter 20 includes first and second DC terminals 24, 26 and a plurality of converter branches 28. Each converter branch 28 extends between the first and second DC terminals 24, 26 and includes first and second branch portions 30, 32 separated by corresponding AC terminals 34. In each converter branch 28, the first branch portion 30 extends between the first DC terminal 24 and the AC terminal 34, while the second branch portion 32 extends between the second DC terminal 26 and the AC terminal 34.

[0110] In use, the first and second DC terminals 24, 26 of the voltage source converter 20 are respectively connected to the DC network 36. In use, the AC terminal 34 of each converter branch 28 of the voltage source converter 20 is connected to the corresponding AC phase of the three-phase AC network 40 via a star-delta transformer arrangement 42. The three-phase AC network 40 is an AC power grid 40. It is contemplated that, in other embodiments of the invention, the transformer arrangement may be of a different type, such as a star-star transformer arrangement.

[0111] Each branch section 30, 32 includes a switching valve, which includes a chain link converter defined by a plurality of modules 44 connected in series.

[0112] Each module 44 can vary in topology, and examples are described below.

[0113] Figure 2a The structure of an exemplary first module 44, in the form of a half-bridge module 44a, is schematically shown. The half-bridge module 44a includes a pair of switching elements 46 and a capacitor 48. Each switching element 46 of the half-bridge module 44a is in the form of a silicon carbide (SiC)-based MOSFET connected in parallel with an anti-parallel diode. The pair of switching elements 46, in the half-bridge arrangement, are connected in parallel with the capacitor 48 to define a two-quadrant unipolar module 44a, which can provide zero or positive voltage and can conduct current in both directions.

[0114] Figure 2b The structure of an exemplary first module 44, in the form of a full-bridge module 44b, is schematically shown. The full-bridge module 44b includes two pairs of switching elements 46 and capacitors 48. Each switching element 46 of the full-bridge module 44b is in the form of a SiC-based MOSFET connected in parallel with an anti-parallel diode. The pairs of switching elements 46 are connected in parallel with capacitors 48 in a full-bridge arrangement to define a four-quadrant bipolar module 44b, which can provide negative voltage, zero voltage, or positive voltage and can conduct current in both directions.

[0115] Figure 3a The structure of an exemplary second module 44, in the form of a half-bridge module 44c, is schematically shown. The half-bridge module 44c includes a pair of switching elements 46 and a capacitor 48. Each switching element 46 of the half-bridge module 44c is in the form of a silicon (Si) semiconductor-based IGBT connected in parallel with an anti-parallel diode. The pair of switching elements 46, in a half-bridge arrangement, are connected in parallel with the capacitor 48 to define a two-quadrant unipolar module 44c, which can provide zero or positive voltage and can conduct current in both directions.

[0116] Figure 3b The structure of an exemplary second module 44, in the form of a full-bridge module 44d, is schematically shown. The full-bridge module 44d includes two pairs of switching elements 46 and capacitors 48. Each switching element 46 of the full-bridge module 44d is in the form of a Si semiconductor-based IGBT, connected in parallel with an anti-parallel diode. The pairs of switching elements 46 are connected in parallel with capacitors 48 in a full-bridge arrangement to define a four-quadrant bipolar module 44d, which can provide negative voltage, zero voltage, or positive voltage and can conduct current in both directions.

[0117] In each switching valve, module 44 includes a plurality of first modules 44 and a plurality of second modules 44. Each switching valve is configured such that, in each switching valve, the second module 44 comprises a majority, for example, 95% to 99%, of the plurality of modules 44, while the first module comprises a small portion, for example, 1% to 4%, of the plurality of modules 44. The structure of each first module 44 is the same as that of each second module 44, except that the switching element 46 of each first module 44 is a SiC-based switching element, and the switching element 46 of each second module 44 is a Si semiconductor-based switching element.

[0118] The structure of a given module 44 includes the arrangement and type of the switching elements 46 and energy storage devices 48 used in the given module 44. It will be understood that it is not necessary for the structure of each first module 44 to be identical to the structure of each second module 44. For example, multiple modules 44 may include a combination of a half-bridge first module 44a and a full-bridge second module 44d, or a combination of a full-bridge first module 44b and a half-bridge second module 44c. Furthermore, it is not necessary for all of the first modules 44 to have the same module structure, nor is it necessary for all of the second modules 44 to have the same module structure.

[0119] It will be understood that the material of the switching element 46 can be varied. Preferably, each switching element 46 of each first module 44 has a higher switching frequency capability compared to each switching element 46 of each second module 44. For example, each SiC-based MOSFET can be replaced by another switching element based on a wide-bandgap material. Examples of other wide-bandgap materials include, but are not limited to, boron nitride, gallium nitride, and aluminum nitride.

[0120] Contemplated, in other embodiments of the invention, each switching element 46 of each module 44 may be replaced by a gate turn-off thyristor (GTO), another field-effect transistor (FET), an injection-enhanced gate transistor (IEGT), an integrated gate-commutated thyristor (IGCT), a two-mode insulated-gate transistor (BIGT), or any other self-commutated semiconductor device. It is also contemplated, in other embodiments of the invention, that each diode may be replaced by a plurality of diodes connected in series.

[0121] By changing the state of the switching element 46, the capacitor 48 of each module 44 is selectively bypassed or inserted into the corresponding chain link converter. This selectively directs current through the capacitor 48 or bypasses the current through the capacitor 48, causing the module 44 to provide zero or positive voltage.

[0122] When the switching element 46 in module 44 is configured to form a short circuit in module 44, the capacitor 48 of module 44 is bypassed, thereby short-circuiting the bypass capacitor 48. This allows current in the corresponding chain link converter to pass through the short-circuited and bypassed capacitor 48, and therefore module 44 provides zero voltage, i.e., module 44 is configured in bypass mode.

[0123] When the switching element 46 in module 44 is configured to allow current to flow into and out of the capacitor 48 in the corresponding chain link converter, the capacitor 48 of module 44 is inserted into the corresponding chain link converter. The capacitor 48 then charges or discharges its stored energy to provide a positive voltage; that is, module 44 is configured in non-bypass mode.

[0124] In this way, the switching element 46 in each module 44 is switchable to control the flow of current through the corresponding capacitor 48.

[0125] It is possible to accumulate a combined voltage across each chain link converter by inserting capacitors from multiple modules 44, each providing its own voltage, into each chain link converter. This combined voltage is higher than the voltage available from each of its individual modules 44. In this way, switching of the switching element 46 in each module 44 enables each chain link converter to provide a step-variable voltage source, which allows voltage waveforms to be generated using a step-approximation across each chain link converter. Therefore, the switching element 46 in each branch 30, 32 can be switched to selectively allow and block the flow of current through the corresponding capacitor 48 in order to control the voltage across the corresponding branch 30, 32.

[0126] In other embodiments of the invention, each module 44 may be replaced by another type of module comprising a plurality of switching elements and at least one energy storage device, wherein the plurality of switching elements and said or each energy storage device in each such module are arranged to be combined to selectively provide a voltage source.

[0127] In other embodiments of the invention, it is also envisioned that the capacitor 48 in each module 44 may be replaced by another type of energy storage device (e.g., a battery or fuel cell) capable of storing and releasing energy to provide voltage.

[0128] Each switching valve includes multiple bypass devices 50. Each bypass device 50 is connected in parallel with a corresponding module in module 44. More specifically, each bypass device 50 includes a bypass switching element 52 connected across the terminals of the corresponding module 44. Each bypass switching element 52 may take the form of a semiconductor switching element including one or more semiconductor switching devices.

[0129] The electrical assembly also includes a controller 54, which is programmed to control the switching of the switching element 46 and the bypass device 50.

[0130] For simplicity, controller 54 is described by way of example as an implementation of a single control unit. In other embodiments, controller 54 may be implemented as multiple control units. The configuration of controller 54 may vary depending on the specific requirements of voltage source converter 20. For example, controller 54 may include multiple control units, each programmed to control the switching element 46 of a corresponding module in module 44 and the switching of the corresponding bypass device 50. Each control unit may be configured to be inside or outside the corresponding module 44. Alternatively, controller may include a combination of one or more control units inside the corresponding module 44 and one or more control units outside the corresponding module 44. Each control unit may be configured to communicate with at least one other control unit via a telecommunications link.

[0131] The electrical assembly also includes a current sensor 56a and a voltage sensor 56b, wherein the current sensor 56a is configured to measure the AC voltage of the AC network 40. ac The voltage sensor 56b is configured to measure the voltage V at the common coupling point (pcc). pcc Each sensor 56a, 56b can be configured to communicate with the controller 54 via a telecommunications link.

[0132] The controller 54 and sensors 56a and 56b can be separate from or form part of the voltage source converter 20.

[0133] Operating reference for electrical assembly components Figures 4 to 8 The description is as follows.

[0134] To transfer power between DC and AC networks 36, 40, controller 54 controls the switching of switching elements 46 of the second module 44 to cut into and out of the circuit between the respective DC and AC terminals 24, 26, 34 of the capacitors of the corresponding branch sections 30, 32, to interconnect the DC and AC networks 36, 40. Controller 54 switches the switching elements 46 of the second module 44 for each branch section 30, 32 to provide a step variable voltage source between the respective DC and AC terminals 24, 26, 34, and thereby generates a voltage waveform to control the configuration of the AC voltage waveform at the corresponding AC terminal 34 to facilitate power transfer between the DC and AC networks 36, 40.

[0135] Preferably, only the second module 44 is used to perform the power transfer function, while the first module 44 is bypassed by configuring a bypass device 50 to improve the efficiency of power transfer. Furthermore, the second module 44 can be operated to perform protection functions for the voltage source converter 20 and the DC and AC networks 36, 40.

[0136] The first module 44 provides module redundancy for the voltage source converter 20 because in certain situations, such as when one or more second modules 44 are offline or in operating environments where a greater number of modules 44 than can be provided by the second modules 44, the first module 44 can be operated to perform power transfer and protection functions.

[0137] The impedance Z of the AC network is 40Ω. g The dynamics of AC network 40 can vary over time due to changes in its operating conditions, which may be caused by black start, variations in power generation equipment due to selective connection and disconnection, varying loads, and the energizing sequence of electrical network equipment or components (e.g., transformers, cables, and switching devices). The dynamics of AC network 40 may be difficult to control reliably. This is partly due to the resistivity Z of AC network 40. g The changes in the AC network may be volatile due to the increased penetration of renewable energy systems, and may be unpredictable due to the increasing number of distributed power sources and loads. The impedance Z of the AC network is 40. g This change poses a risk of system instability, which may in turn lead to unwanted power oscillations, equipment damage, and / or tripping of the voltage source converter 20 and AC network 40 to an offline state.

[0138] To reduce the risk of system instability, the controller 54 controls the switching of the switching element 46 of the first module 44 to perform the characterization process in coordination with the sensors 56a and 56b.

[0139] The first non-restrictive example of the characterization process is described below.

[0140] The controller 54 controls the switching of at least one selected first module 44 to change its output voltage waveform, such that said or each selected first module 44, combined with the inductor 58 in the same branch 30, 32, provides a variable resistivity Z. L The SiC-based MOSFETs of each selected first module 44 switch at a higher frequency than the Si semiconductor-based IGBTs of the second module 44. Figure 4 The first module 44 is shown operating in combination with inductor 58 to provide variable resistivity Z. L This also has the equivalent resistive impedance Z of the voltage source converter 20. CThe effect of changing it to a variable. The equivalent resistivity Z of voltage source converter 20. C Given by the following equation:

[0141]

[0142] Where ω is the angular frequency, and L t It is the transformer inductance.

[0143] Due to the modification of the equivalent impedance Z of voltage source converter 20 C AC network 40 communication i ac It has been modified.

[0144] Figure 5 This illustrates when one or more selected first modules 44 are operated as variable impedance to modify the equivalent impedance Z of the voltage source converter 20. C Equivalent circuit of voltage source converter 20 and AC network 40.

[0145] By changing the equivalent impedance Z of voltage source converter 20 C The resistivity Z of AC network 40 can be determined using the following Kirchhoff equation. g and equivalent operating voltage v g Estimate:

[0146]

[0147] Where v pcc (k) is the voltage at the common coupling point measured by voltage sensor 56b at time k, and i ac (k) is the AC measured by the current sensor 56a at time k in the AC network 40.

[0148] The controller processes the measured voltage v by applying a least-squares algorithm, such as a recursive least-squares algorithm, to the above equation. pcc (k) and the measured current i ac (k) in order to obtain the resistivity Z for AC network 40 g and equivalent operating voltage v g The estimated value. It will be understood that other methods exist for solving the above equation to obtain the resistivity Z for AC network 40. g and equivalent operating voltage v g The estimated value.

[0149] Therefore, the equivalent impedance Z of the voltage source converter 20 C The change enables estimation of the impedance Z of the AC network 40. g and equivalent operating voltage v gThis can be done without requiring new active power (P) and reactive power (Q) operating points.

[0150] A second non-restrictive example of the characterization process is described below.

[0151] The controller 54 controls the switching of at least one selected first module 44 to change its output voltage waveform, such that said or each selected first module 44 acts as a variable voltage source to inject a perturbation harmonic voltage v at the common coupling point in a range of different frequencies that are multiples of the angular frequency ω0. p The SiC-based MOSFETs of each selected first module 44 switch at a higher frequency than the Si semiconductor-based IGBTs of the second module 44. Figure 6 The operation of the first module 44, acting as a controllable disturbance voltage source, is illustrated. The disturbance harmonic voltage v is... p The injection also causes harmonic current components to be injected into the AC network 40's AC i ac In the middle. Because at time k, the impedance Z of voltage source converter 20 at a given frequency ω(n) is... c (n) is known, at time k, the AC network 40's AC i ac (n) is given by the following formula:

[0152]

[0153] Sensor 56 measures the AC network 40 at a given frequency ω(n) using AC i. ac And the measured AC i ac The above equation is provided to controller 54, which then uses it to estimate the resistivity Z of AC network 40 at a given frequency ω(n). g (n).

[0154] If the AC network has a voltage of 40V... g If it contains one or more harmonics, then when v p When (n) equals zero, the superposition principle can be used to obtain the AC i ac (n) Measure the one or more harmonics and subtract the one or more harmonics from the above equation to estimate the impedance Zg(n) of AC network 40 at different frequencies.

[0155] Online frequency scanning can be performed within a frequency range that is a multiple of the angular frequency ω0 in order to characterize the AC network impedance Z at each frequency. g . Figure 7 This illustrates when one or more selected first modules 44 operate as controlled disturbance voltage sources to inject disturbance harmonic voltages within a frequency range in order to inject harmonic current components into the AC network 40. acEquivalent circuit of intermediate voltage source converter 20 and AC network 40.

[0156] Therefore, the voltage source converter 20 can be used as an in-line integrated impedance analyzer to estimate the resistivity Z of the AC network 40. g .

[0157] During the characterization process, the injected disturbance voltage can be 1% or about 1% of the output voltage of the voltage source converter 20.

[0158] After completing the characterization process, the controller 54 uses the characterized impedance Z. g To estimate the stability of the system defined by the voltage source converter 20 and the AC network 40, such as by the ratio Z c / Z g Given that the system is estimated to be at risk of instability, i.e., ratio Z. c / Z g If the value is close to -1, the controller 54 controls the switching of one or more switching elements in the first module 44 to change their output voltage waveform or their output voltage waveform, so as to modify the impedance Z of the voltage source converter 20. c With control ratio Z c / Z g This increases the system's stability. The Nyquist stability criterion can be used to help determine and configure the stability of a system; the Nyquist stability criterion explores a frequency range in which Z... c / Z g =-1.

[0159] As a result, the configuration of the electrical components used to perform the characterization process enables the voltage source converter 20 to respond to the impedance Z of the AC network 40. g Any change to its electrical impedance Z c Real-time adjustments are made. This not only enhances the control performance of the voltage source converter 20 under varying operating conditions of the AC network 40, but can also be used to provide increased stability margin under weak AC power grids and time-varying parameters.

[0160] Furthermore, after the characterization process is completed, the control of the voltage source converter 20 can be adapted in various ways to enhance its performance and / or improve system stability.

[0161] The characterization process of the control of the voltage source converter 20 and the subsequent response adaptation are summarized as a second example of the reference characterization process. Figure 8 A series of steps in the flowchart. To understand, Figure 8 The flowchart is a first example of a process adapted for characterization.

[0162] In the first step 100, one or more first modules 44 are operated to inject a disturbance voltage v. p This is followed by the measurement of the modified AC network 40. ac The second step, 102, is the result of the injection of the disturbance voltage vp.

[0163] In step 104, for example, a recursive least squares algorithm is used to estimate the resistivity Z of the AC network 40. g and equivalent operating voltage v g .

[0164] Step 4, 106, involves a determination process based on the cost function J. The cost function J is defined based on a weighted combination of several variables associated with the voltage source converter 20, such as: the switching frequency of the SiC-based MOSFETs in the first module 44; the switching frequency of the Si semiconductor-based IGBTs in the second module 44; conduction losses; the number of modules of circuitry integrated into the voltage source converter 20; module voltage ripple; module energy levels, etc. Typically, the cost function J will be non-linear. A determination threshold J0 is defined.

[0165] As described above, after completing the characterization process, the controller 54 uses the characterized impedance Z g To estimate the stability of the system defined by the voltage source converter 20 and the AC network 40, such as by the ratio Z c / Z g Given. If necessary, the impedance Z of the voltage source converter 20 can be subsequently modified. c This allows changing the resistivity Z of the voltage source converter 20. c To achieve one or more objectives, such as system stability, meeting performance standards, oscillation damping, etc.

[0166] Either or both of the first and second modules 44 can be controlled by the controller 54 to change their output voltage waveforms in order to modify the resistive impedance Z of the voltage source converter 20. c If the value of the cost function J exceeds the decision threshold J0, then in step 5 108, the first module 44 is used to modify the voltage source converter impedance Z. c This is to benefit from the overall performance of the voltage source converter, as defined by the cost function J. However, if the value of the cost function J is equal to or below the decision threshold J0, the second module 44 is used in step 110 to modify the voltage source converter impedance Z. c .

[0167] Furthermore, after the characterization process is completed, the controller 54 can process the characterized impedance Z of the AC network 40. gTo control either or both of the first and second modules 44 in order to adapt the control of the voltage source converter 20 by performing at least one of the following:

[0168] • Modify the control parameters of voltage source converter 20;

[0169] • Provide or increase active damping for one or more oscillations in the AC network 40; and

[0170] • Provides active filtering.

[0171] therefore, Figure 1 The voltage source converter 20 combines a first module 44 of SiC-based switching elements 46 and a second module 44 of Si semiconductor-based switching elements 46 in a hybrid topology to provide the functionality of an online integrated frequency characterization of the AC network 40, which has faster switching capabilities, in conjunction with the normal operating mode of the voltage source converter 20 performed by the second module 44. Therefore, Figure 1 The configuration of the electrical assembly eliminates the need for a separate and dedicated impedance analyzer, which incurs additional installation and operating costs, increases the overall size and weight of the electrical assembly, and is less scalable for use with voltage source converters of different ratings and for different characterization processes.

[0172] In addition, during the characterization process, the first module 44 provides the electrical assembly with the ability to perform online frequency characterization of the AC network 40, while the voltage source converter 20 and the AC network 40 do not need to go offline and do not need to change the steady-state operating conditions of the voltage source converter 20 and the AC network 40.

[0173] Furthermore, the use of the first module 44 in the characterization process advantageously allows the characterization process to be scaled to be compatible with converters with different ratings having different numbers of modules, and also allows for variations in the number of modules used in the characterization process to change the parameters of the characterization process without incurring significant costs in redesigning and building new converter structures.

[0174] In addition to performing the characterization process, the first module 44 can also be configured to provide one or more additional functions, such as active power damping and filtering with increased dynamic bandwidth, electrical fault management, module redundancy, and impedance simulation under steady-state operating conditions, without interfering with the normal operating mode of the voltage source converter 20 performed by the second module 44. The higher switching frequency capability of the SiC-based switching elements in the first module 44 enables it to provide better active damping compared to the second module 44, which has Si semiconductor-based switching elements with lower switching frequency capabilities. Therefore, the first module 44 can actively dampen higher-frequency oscillations in the AC network 40 that cannot be handled by the second module 44.

[0175] Unless the context otherwise indicates, preferred and alternative aspects, features, or parameters of the present invention should be considered as disclosed in combination with any and all preferred and alternative combinations of all other aspects, features, and parameters of the present invention.

Claims

1. An electrical assembly comprising a converter (20) for connection to an electrical network (40), the converter (20) comprising at least one module (44), the at least one module (44) comprising at least one switching element (46) and at least one energy storage device (48), the at least one switching element (46) and the at least one energy storage device (48) in the at least one module (44) being arranged combinatorially to selectively provide a voltage source, the electrical assembly comprising a controller (54) configured to selectively control the switching of the at least one switching element (46) in the at least one module (44), wherein the electrical assembly comprises a sensor (56a) configured to measure the current (i) of the electrical network (40). ac The controller (54) and the sensor (56a) are configured to operate in coordination to execute the electrical parameters (Zg, v) of the electrical network (40). g The representation of ) makes it possible to use: The controller (54) selectively controls the switching of at least one switching element (46) in at least one module (44) to modify the electrical parameters (Z) of the converter (20). c v p ), so as to modify the current (i) of the electrical network (40). ac ); The sensor (56a) measures the obtained modified current (i) of the electrical network (40). ac );as well as The controller (54) processes the measured modified current (i) obtained from the electrical network (40). ac ), so as to characterize the electrical parameters (Z) of the electrical network (40). g v g ), The electrical assembly further includes at least one first module (44) and at least one second module (44), wherein the controller (54) is configured to selectively control the switching of at least one switching element (46) in the at least one first module (44) to execute the electrical parameters (Z) of the electrical network (40). g v g The controller (54) is configured to selectively control the switching of at least one switching element (46) in at least one second module (44) to perform the normal operating mode of the converter (20). The at least one switching element (46) of the at least one first module (44) has a higher switching frequency capability compared to the at least one switching element (46) of the at least one second module (44).

2. The electrical assembly according to claim 1, wherein, The controller (54) is configured to process the electrical parameters (Z) characterized by the electrical network (40). g v g ), to control the switching of the at least one switching element (46) in the at least one module (44) so ​​as to adapt to the control of the converter (20).

3. The electrical assembly according to any one of the preceding claims, wherein, The controller (54) is configured to process the electrical parameters (Z) characterized by the electrical network (40). g v g In order to control the switching of at least one switching element (46) in at least one module (44), so as to adapt the control of the converter (20) by performing at least one of the following: • Modify the equivalent impedance (Z) of the converter (20). c ); • Modify the control parameters of the converter (20); • Provide or increase active damping for one or more oscillations in the electrical network (40); • Provides active filtering.

4. The electrical assembly according to any one of claims 1-2, wherein, The controller (54) is configured to process the measured modified current (i) of the electrical network (40). ac ), so as to characterize the electrical impedance (Z) of the electrical network (40). g ) and / or the operating voltage (V) of the electrical network (40) g ).

5. The electrical assembly according to any one of claims 1-2, wherein, The controller (54) is configured to selectively control the switching of at least one switching element (46) in at least one module (44) to provide variable impedance to modify the impedance (Z) of the converter (20). c ), so as to modify the current (i) of the electrical network (40). ac ).

6. The electrical assembly according to any one of claims 1-2, wherein, The controller (54) is configured to selectively control the switching of at least one switching element (46) in at least one module (44) to inject a disturbance voltage in order to modify the current (i) of the electrical network (40). ac ).

7. The electrical assembly according to any one of claims 1-2, wherein, The controller (54) and the sensor (56a) are configured to operate in coordination to execute the electrical parameters (Z) of the electrical network (40) within a frequency range. g v g The characterization of ).

8. An electrical assembly comprising a converter (20) for connection to an electrical network (40), the converter (20) comprising at least one first module (44) and at least one second module (44), each of the first module (44) and the second module (44) comprising at least one switching element (46) and at least one energy storage device (48), the at least one switching element (46) and the at least one energy storage device (48) in the at least one module (44) being arranged to be combinable to selectively provide a voltage source, the electrical assembly comprising a controller (54) configured to selectively control the switching of the at least one switching element (46) in the at least one module (44). The controller (54) is configured to selectively control the switching of at least one switching element (46) in at least one second module (44) to execute the normal operating mode of the converter (20). The controller (54) is configured to respond to receiving the characterized electrical parameters (Z) of the electrical network (40). g v g ), and process the electrical parameters (Z) characterized by the electrical network (40). g v g To control the switching of at least one switching element (46) in at least one first module (44) to adapt to the control of the converter (20), The at least one switching element (46) of the at least one first module (44) has a higher switching frequency capability compared to the at least one switching element (46) of the at least one second module (44).

9. The electrical assembly according to claim 8, wherein, The controller (54) is configured to respond to receiving the electrical parameters (Z) characterized by the electrical network (40). g v g ), and process the electrical parameters (Z) characterized by the electrical network (40). g v g To control the switching of at least one switching element (46) in at least one first module (44) so ​​as to adapt the control of the converter (20) by performing at least one of the following: • Modify the equivalent impedance (Z) of the converter (20). c ); • Modify the control parameters of the converter (20); • Provide or increase active damping for one or more oscillations in the electrical network (40); • Provides active filtering.

10. The electrical assembly according to any one of claims 8 to 9, wherein, The at least one first module (44) is configured to be bypassable during the normal operating mode of the converter (20).

11. An operating electrical assembly to characterize the electrical parameters (Z) of an electrical network (40). g v g The method, wherein the electrical assembly includes a converter (20) for connection to the electrical network (40), the converter (20) including at least one first module (44) and at least one second module (44), each module (44) including at least one switching element (46) and at least one energy storage device (48), the at least one switching element (46) and the at least one energy storage device (48) in the at least one module (44) being arranged to be combinable to selectively provide a voltage source, wherein the method includes the following steps: Controlling the switching of at least one switching element (46) in at least one module (44) to modify the electrical parameters (Z) of the converter (20) c v p ), so as to modify the current (i) of the electrical network (40). ac ); The modified current (i) obtained by measuring the electrical network (40) ac );as well as The measured modified current (i) obtained by processing the electrical network (40) ac In order to characterize the electrical parameters (Z) of the electrical network (40) g v g ), The method further includes the following steps: Controlling the switching of at least one switching element (46) in at least one first module (44) to execute the electrical parameters (Z) of the electrical network (40). g v g The characterization of ) and Controlling the switching of at least one switching element (46) in at least one second module (44) to execute the normal operating mode of the converter (20), The at least one switching element (46) of the at least one first module (44) has a higher switching frequency capability compared to the at least one switching element (46) of the at least one second module (44).

12. A method based on the parameters (Z) characterized by an electrical network (40) g v g A method of operating an electrical assembly, the electrical assembly including a converter (20) for connection to the electrical network (40), the converter (20) including at least one first module (44) and at least one second module (44), each of the first module (44) and the second module (44) including at least one switching element (46) and at least one energy storage device (48), the at least one switching element (46) and the at least one energy storage device (48) in the at least one module (44) being arranged to be combinable for selectively providing a voltage source, the method comprising the following steps: Control the switching of at least one switching element (46) in at least one second module (44) to execute the normal operating mode of the converter (20); Receive the electrical parameters (Z) characterized by the electrical network (40). g v g );as well as In response to receiving the characterized electrical parameters of the electrical network (40), the characterized electrical parameters (Z) of the electrical network (40) are processed. g v g To control the switching of at least one switching element (46) in at least one first module (44) to adapt to the control of the converter (20), The at least one switching element (46) of the at least one first module (44) has a higher switching frequency capability compared to the at least one switching element (46) of the at least one second module (44).

13. The method of claim 12, comprising the following steps: In response to receiving the characterized electrical parameters of the electrical network (40), the characterized electrical parameters (Z) of the electrical network (40) are processed. g v g To control the switching of at least one switching element (46) in at least one first module (44) so ​​as to adapt the control of the converter (20) by performing at least one of the following: • Modify the equivalent impedance (Z) of the converter (20). c ); • Modify the control parameters of the converter (20); • Provide or increase active damping for one or more oscillations in the electrical network (40); • Provides active filtering.

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