TRANSFORMER DOWNSTREAM VOLTAGE ADJUSTMENT

Abstract

Device (DS) for adjusting the initial output voltage of an electrical transformer (TFM) to obtain a regulated voltage (Vr), the device (DS) comprising: - a converter (CV) providing a primary voltage (V1) from the initial voltage (Vi), - a regulator (REG), issuing adjustment commands to the converter (CV) according to an operating mode, and - a coupling transformer (TFMC) providing a secondary voltage (V2) from the primary voltage (V1), the regulated voltage (Vr) being obtained from the secondary voltage (V2), the operating mode being a "stepped" mode, in which the regulated voltage (Vr) takes a value from a first voltage, a second voltage, and a transition voltage, or a "continuous" mode, in which the regulated voltage (Vr) takes a value between the first voltage and the second voltage. Abstract figure: Figure 1

Description

Title of the invention: VOLTAGE ADJUSTMENT DOWNSTREAM OF TRANSFORMER Technical field

[0001] The present disclosure relates to a device for adjusting the output voltage of an electrical transformer. Prior art

[0002] Existing devices allow the output voltage of an electrical transformer to be adjusted. These devices, called tap changers, load regulators or in English "tap changers", are conventionally used to compensate for voltage variations on the network and maintain the network voltage at an optimal level. To do this, the tap changers modify the number of turns of the main winding of the electrical transformer in order to modify the transformation ratio. In particular, the adjustment winding of such tap changers is integrated into the electrical transformer.

[0003] Other solutions for adjusting the output voltage of an electrical transformer may include manually switching the transformer tap, using parallel converters, or using electronic compensators.

[0004] However, existing solutions for regulating the voltage of a transformer have several disadvantages. First of all, they require integration of the regulating device into the transformer, or at least a modification of its intrinsic operation (for example, a tap changer modifies the number of turns of a winding of the transformer). Thus, existing solutions have an invasive nature in that they generate an impact, a change or at least a contact with the internal components of the electrical transformer. Such voltage regulating solutions may also have electronic complexity, complexity of controlling the voltage regulation or even a need for synchronization with the electrical network operating the electrical transformer.Furthermore, interventions and stresses on the transformer due to the integration of such voltage adjustment devices generate costs and can disrupt the operation of electrical transformers, or even alter their service life. In addition, handling electrical transformers in such a way as to integrate such adjustment devices can present risks. Indeed, the dielectric oil present in electrical transformers can spill and / or lead to risks of pollution and accidents (e.g., explosions, fires). In addition, the operation of the transformer. which can be carried out on high-power electrical lines (for example, in the case of transformer stations connected to high or very high voltage lines, known as "HTB2", "HTB" or even "HTA" in France, which can transform voltages of the order of several tens or even hundreds of kilovolts), short circuits can cause the electrical circuit to open at such powers.

[0005] There is therefore a need to intervene effectively on an electrical circuit so as to allow the adjustment of a voltage at the output of an electrical transformer, while reducing the costs and risks linked to physical intervention on electrical transformers. Summary

[0006] The present disclosure improves the situation.

[0007] A device is proposed for adjusting an initial voltage at the output of an electrical transformer so as to obtain a regulated voltage, the device comprising: - a converter providing a primary voltage from the initial voltage at the output of the electrical transformer, - a regulator, arranged to issue adjustment orders to the converter as a function of at least one operating mode selected from among several, and - a coupling transformer connected in series, downstream and outside the electrical transformer and connected to the converter, the coupling transformer providing a secondary voltage from the primary voltage, the regulated voltage being obtained from the secondary voltage, said operating modes comprising at least one so-called “notch” operating mode, in which the regulated voltage takes a value from among a first voltage, a second voltage and a transition voltage between the first voltage and the second voltage, and a so-called “continuous” operating mode, in which the regulated voltage takes a value between the first voltage and the second voltage.

[0008] Consequently, the proposed device advantageously makes it possible to adjust the output voltage of a transformer in a simple, non-invasive manner because the device does not require intervention or modification of the intrinsic operation of the electrical transformer. The technical and human risks associated with interventions on electrical transformers are therefore reduced. Furthermore, adjusting the voltage without intervention on the transformer makes it possible to increase the service life of the electrical equipment of the electrical transformer.

[0009] Advantageously, the proposed device also makes it possible to modulate the voltage adjustment according to different operating modes, thus making it possible to vary the granularity and the degree of precision of the voltage adjustment depending on the nature of the network needs. For example, for most voltage adjustments (e.g., maintaining a substantially constant voltage in the network), a step-operating mode can be implemented. For precision voltage adjustments, a continuous operating mode can be implemented.

[0010] The notched operating mode advantageously allows the device to transition between three distinct states. The continuous operating mode advantageously allows the device to transition between a plurality of states delimited by the values ​​of the first and second voltages.

[0011] According to another aspect, there is provided a method for adjusting an initial voltage at the output of an electrical transformer implemented by an adjustment device, said device including a converter, a regulator and a coupling transformer connected in series downstream and outside the electrical transformer and connected to the converter, the method comprising the following steps: - collect an initial voltage at the output of the electrical transformer, - obtain adjustment orders based on an operating mode selected from among several, - provide, via the converter, a primary voltage from the initial voltage, - provide, via the coupling transformer, a secondary voltage from the primary voltage, - obtain a regulated voltage from the secondary voltage, said operating modes comprise at least one so-called “notch” operating mode, in which the regulated voltage takes a value from among a first voltage, a second voltage and a transition voltage between the first voltage and the second voltage, and a so-called “continuous” operating mode, in which the regulated voltage takes a value from among the first voltage and the second voltage.

[0012] According to another aspect, there is provided a computer program comprising instructions for implementing all or part of the voltage adjustment method as proposed, when this program is executed by a processor. According to another aspect, there is provided a non-transitory recording medium, readable by a computer, on which such a program is recorded.

[0013] The features set out in the following paragraphs may, optionally, be implemented, independently of one another or in combination with one another:

[0014] In one embodiment, the device and the electrical transformer are connected via an electrical circuit, and in which the device and the electrical transformer are two elements distant from each other.

[0015] Therefore, the voltage adjustment device may be physically decorrelated of the electrical transformer. The adjustment device can, for example, be connected to the output of the electrical transformer. The adjustment device can also be connected downstream of the electrical transformer, further along the power line.

[0016] In one embodiment, the electrical transformer to which the device is connected is an electrical voltage transformer, the device being connected to the Low Voltage side of said transformer.

[0017] In one embodiment, the regulated voltage is obtained by the sum of the initial voltage and the secondary voltage.

[0018] Consequently, the adjustment device makes it possible to adjust the voltage at the output of the transformer by injecting a secondary voltage into the power line, such a secondary voltage makes it possible to counterbalance the initial voltage at the output of the transformer, so as to obtain a regulated voltage at the loads.

[0019] In one embodiment, the coupling transformer is configured by a predefined transformation ratio, the secondary voltage being obtained by the product of the primary voltage by the transformation ratio.

[0020] Consequently, the transformer ratio, or transformation ratio, advantageously makes it possible to impose the maximum voltage injection values ​​and to delimit the secondary voltage injected onto the line and making it possible to regulate the voltage at the output of the electrical transformer.

[0021] In one embodiment, the converter comprises a plurality of semiconductor blocks forming switching switches, the switching of each of said switches depending on the adjustment orders issued by the regulator, said adjustment orders further depending at least on the initial voltage and resulting in switching sequences controlling the switching of said switches.

[0022] Therefore, the voltage adjustment can be implemented by simple, inexpensive, and easily circuited power electronic components. In particular, the voltage adjustment can be implemented according to variable adjustment orders, dependent on one or more parameters, as illustrated below.

[0023] In one embodiment, the adjustment orders and the switching sequences controlling the switching of said switches depend at least on: - the selected operating mode, and / or - an operating order predefined and stored by the regulator, and / or - a sign of the initial tension, and / or - a switching state of the switches before said switching, and / or - a zero crossing of the current intensity at the converter output, and / or - a phase shift at the converter input, and / or - a CV converter switching period.

[0024] Therefore, the adjustment device advantageously makes it possible to adjust the tension at the output of the transformer starting from any switching state of the switches (for example, linked to previous adjustment orders), and reaching a new switching state of the switches allows the implementation of the desired adjustment.

[0025] In particular, the adjustment implemented by the device may depend on a predefined operating order: such an operating order may be predefined at the network level, for example by an order to maintain a constant voltage at a predefined value in the network. The adjustment implemented by the device may also depend on a switching state of the switches, in other words, whether each switch is open or closed.

[0026] Advantageously, taking such parameters into account makes it possible to choose the nature and timing of the adjustment, so as to optimize the adjustment orders, for example in order to favor soft switching (when possible), rather than hard switching of the switches.

[0027] In one embodiment, in the notch operating mode, the switching sequences control a switching of the switches, so that the primary voltage takes one of the following values: the value of the initial voltage, a zero value, a value opposite the value of the initial voltage, the transition voltage being obtained when the primary voltage takes the zero value.

[0028] In particular, in the notched operating mode, the switching of the switches can be implemented when the intensity of the electric current passes through zero. Advantageously, the constraints and disturbances induced by the proposed adjustment are thus reduced.

[0029] In one embodiment, in the continuous operating mode, the switching sequences control switching of the switches according to a modulation ratio between -1 and 1, so that, over a switching period of said switches, the primary voltage is expressed by: V, = a * Vi Or : - Vi is the primary voltage at the converter output, - a is the modulation ratio, - Vi is the initial voltage at the output of the electrical transformer.

[0030] In one embodiment, in the continuous operating mode, the device further comprises an input filter and an output filter of the converter.

[0031] Consequently, the use of filters advantageously makes it possible to reduce harmonic disturbances at the input and output of the converter of the device (in voltage at the output of the converter and in current at the input of the converter). Brief description of the drawings

[0032] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which: Fig. 1

[0033] [Fig-1] shows a diagram of a voltage adjustment device according to a method of rea lization. Fig. 2

[0034] [Fig.2] shows details of a converter in a voltage adjustment device according to one embodiment. Fig. 3

[0035] [Fig.3] shows steps of implementing a voltage adjustment method according to one embodiment. Fig. 4

[0036] [Fig.4] shows the implementation of a voltage adjustment method according to a first embodiment. Fig. 5

[0037] [Fig.5] shows the implementation of a voltage adjustment method according to a first embodiment. Fig. 6

[0038] [Fig.6] shows the implementation of a voltage adjustment method according to a first embodiment. Fig. 7

[0039] [Fig.7] shows the implementation of a voltage adjustment method according to a first embodiment. Fig. 8

[0040] [Fig.8] shows the implementation of a voltage adjustment method according to a first embodiment. Fig. 9

[0041] [Fig.9] shows the implementation of a voltage adjustment method according to a first embodiment. Fig. 10

[0042] [Fig. 10] shows a tension adjustment device according to one embodiment. Fig. 11

[0043] [Fig. 11] shows the implementation of a voltage adjustment method according to a second embodiment. Fig. 12

[0044] [Fig. 12] shows the implementation of a voltage adjustment method according to a second embodiment. Fig. 13

[0045] [Fig. 13] shows the implementation of a voltage adjustment method according to a second embodiment. Description of the embodiments

[0046] Reference is now made to Figures 1 and 2. Figures 1 and 2 represent a portion of an electrical circuit comprising at least one TFM electrical transformer and a voltage adjustment device, or DS device. The portion of the electrical circuit represented in Figures 1 and 2 may, for example, correspond to a portion of an electrical distribution or transmission network. In the context of the French electrical network, the TFM electrical transformer represented may, for example, correspond to a voltage transformer station making it possible to connect a medium voltage distribution network, known as "HTA" and comprising voltage lines of several tens of kilovolts (or kV), to a low voltage distribution network, known as "BT" and comprising voltage lines of several hundreds of volts (or V). The TFM electrical transformer represented may, for example, correspond to an HTA / BT transformer station.

[0047] The DS device can be connected to the TFM electrical transformer via a Low Voltage (or LV) side of the TFM transformer. The connection of the TFM transformer along a High Voltage A (or HTA) side is not shown in Figures 1 and 2. The DS device can, for example, provide the connection between the TFM electrical transformer and the loads supplied by the electrical network (not shown in Figures 1 and 2).

[0048] The DS device can be connected downstream of the TFM electrical transformer. In particular, in a preferred embodiment, the DS device can be separate and remote from the TFM electrical transformer. In other words, the DS device can be connected to the terminals of the TFM electrical transformer at the output of the TFM transformer, as shown in Figures 1 and 2. The DS device can also be connected at any point of the LV network, remote and downstream from the terminals of the TFM electrical transformer.

[0049] The voltage adjustment device DS is arranged in the electrical circuit so as to take as input an initial voltage V; at the output of the transformer TFM and to inject a secondary voltage V2 into the electrical line (the downstream part of the network). In particular, the secondary voltage V2 injected into the electrical line is a voltage in series with respect to the initial voltage V; so that the electrical voltage at the electrical loads at the output of the device DS is a regulated voltage Vr, dependent on the initial voltage V; and the secondary voltage V2. In one embodiment, the regulated voltage Vr is the sum of the initial voltage V; and the secondary voltage V2.

[0050] The voltage adjustment device DS comprises at least one converter CV, one regulator REG and one coupling transformer TFMC.

[0051] The CV converter may correspond to a portion of an electrical circuit configured to convert the initial voltage V; at the output of the electrical transformer TFM into a primary voltage Vp. For this, the CV converter may include electronic components with power semiconductors. In particular, as detailed in [Fig.2], the CV converter may include blocks of electronic components arranged in an electrical bridge assembly. The CV converter may correspond to a single-phase matrix converter. Alternatively, the CV converter may be a three-phase matrix converter. The blocks of electronic components of the CV converter may correspond to blocks of switching switches S1, S2, S3, S4.Each of the switching switch blocks Si, S2, S3, S4 is configured to switch according to a switching sequence so as to open or close the portion of the electrical circuit corresponding to each switching switch block. For this, each switching switch block Si, S2, S3, S4 may include pairs of transistors (in switching) Ci, C2, C3, C4, Cr, C2-, Cy, C4-coupled to antiparallel diodes Db D2, D3, D4, D'i, D'2, D'3, D'4. A transistor coupled to a diode may form a switch. For example, with reference to [Fig.2], block Si comprises two switches formed respectively by the pairs (Ci, Di) and (Cy, Di ), block S2 comprises two switches formed respectively by the pairs (C2, D2) and (C2-, D2 ), block S3 comprises two switches formed respectively by the pairs (C3, D3) and (C3-, D3 ) and block S4 comprises two switches formed respectively by the pairs (C4, D4) and (C4-, D4 ).The switching carried out by the different switching switch blocks Si, S2, S3, S4 then makes it possible to convert the initial voltage V; at the input of the CV converter into a primary voltage Vb. Such switching according to a given switching sequence as well as such voltage conversion will be detailed later in the description. The switching carried out by the different switching switch blocks Sb S2, S3, S4 can be implemented according to adjustment orders received by the CV converter. In particular, such adjustment orders can be distinct and different for the switching switch blocks Si, S2, S3, S4. Such adjustment orders can be issued by the regulator REG of the DS device.

[0052] The regulator REG may correspond to an internal controller configured to control the operation of the CV converter, and in particular of the different switching switch blocks S1, S2, S3, S4. The regulator REG may issue adjustment commands to the CV converter. The adjustment commands issued by the regulator REG may be associated with one or more switching sequences to be operated by each of the switching switch blocks S1, S2, S3, S4. The commands adjustment can be determined by the REG regulator depending on at least one of: - a selected operating mode of the voltage adjustment device DS, - data of the electrical circuit, which can be measured on the electrical line (in particular at the input of the CV converter) and / or at a point DN on the electrical line on a primary of the coupling transformer TFMC (i.e., at the output of the CV converter), as represented by the dotted arrows in figures 1 and 2, - the last switching state of the different switches of the switching switch blocks Sb S2, S3, S4, - an operating order targeted by the REG regulator, for example coming from an operating objective at the scale of the electricity network.

[0053] The operating mode of the DS device can be selected from at least one so-called “step” operating mode and one so-called “continuous” operating mode. The distinction and operation of the different operating modes of the DS device will be detailed in the remainder of the description.

[0054] The data of the electrical circuit considered by the REG regulator to determine the adjustment orders can be measured (for example continuously and / or periodically) using sensors present on the electrical line and at the input / output of the CV converter and connected to the REG regulator. The data considered can include for example: - the intensity measured at the primary DN of the coupling transformer TFMC, and in particular the sign of such intensity and / or the zero crossing of such intensity, and / or - the initial voltage V;, and / or - the current intensity on the power line Ir, as shown in figures 1 and 2, and / or - the advance or delay of the current on the power line Ir compared to the initial voltage V;.

[0055] The adjustment orders issued by the regulator REG may in particular depend on the last switching state of the various switching switch blocks S1, S2, S3, S4. In other words, the adjustment orders issued by the regulator REG may depend on a current open or closed state of each of the switches of the switching switch blocks S1, S2, S3, S4 or even on a relative state (open or closed) of the switching switch blocks S1, S2, S3, S4 with respect to each other. Equivalently, the adjustment orders issued by the regulator REG may depend on the last adjustment orders issued by the regulator REG to the CV converter.

[0056] The adjustment orders issued by the REG regulator may in particular depend on a adjustment objective targeted by the voltage adjustment device DS. Such an adjustment objective can be translated by an operating order stored by the regulator REG, coming for example from a control or command device of the electrical network. For example, the regulator REG can store an operating order aimed at maintaining the network voltage at a given value.

[0057] To determine the adjustment commands to be issued to the CV converter, the regulator REG may comprise a processing unit including at least one processor PROC and a memory unit MEM, as shown in [Fig. 1]. The memory unit MEM of the regulator REG may be configured to store the data measured on the electrical circuit, the selected operating mode, a history of the adjustment commands issued (or equivalently, a current state of the switching switch blocks S1, S2, S3, S4 of the CV converter) and / or an operating command. The processor of the regulator REG may be configured to determine the adjustment commands from the data stored in the memory unit MEM.

[0058] The voltage adjustment device DS further comprises a coupling transformer TFMC configured to transform the primary voltage Vi at the output of the CV converter into a secondary voltage V2. In particular, the coupling transformer TFMC is configured to transform the primary voltage Vi according to a preconfigured transformation ratio. The transformation ratio of the coupling transformer TFMC satisfies: V2 = X % * V! where Vi is the primary voltage, V2 is the secondary voltage and X% is the transformation ratio of the TFMC coupling transformer, expressed in percentages (%). For example, such a transformation ratio can be pre-configured at 2.5 percent (%)•

[0059] Reference is now made to [Fig. 3]. [Fig. 3] represents steps of implementing a method for adjusting the output voltage of an electrical transformer TFM, implemented by a voltage adjustment device DS, as shown in Figures 1 and 2.

[0060] At a step 300, a current state of the electrical circuit is considered. An initial voltage value V; at the output of the electrical transformer TFM and an intensity of the electric current Ir flowing in the electrical line are considered. The sign and / or the advance or the delay of the initial voltage V; relative to the intensity of the electric current ICv at the output of the CV converter can be considered. In addition, a current switching state of the different switching switch blocks Si, S2, S3, S 4 of the CV converter is considered. For example, with reference to [Fig. 4], all the switches (Ci, Di), (Cr, Di ), (C2, D2) and (C2-, D2 ) of the switching switch blocks Si and S2 are open and all the switches (C3, D3), (C3-, D3 ), (C4, D4) and (C 4-, D4 ) of the switching switch blocks S3 and S4 are closed. Data measured at the primary DN of the coupling transformer TFMC of the DS device are considered.

[0061] In step 300, all of the data considered can be obtained by the regulator REG. The regulator REG further stores at this step an operating order for the device DS. For example, the regulator REG can store an order to maintain the voltage at the loads at a given value. Such an operating order can for example be issued by a remote control device of the device DS (not shown in the figures), managing for example the maintenance of the voltage at the scale of the electrical network. Such a remote control device can furthermore remotely and in a coordinated manner control a plurality of similar DS devices.

[0062] In a step 310, adjustment orders are determined by the regulator REG to be sent to the CV converter, so as to trigger a switching sequence to be executed by each of the switching switch blocks S1, S2, S3, S4. Such adjustment orders are determined by the regulator REG based on the data obtained in step 300. For example, by considering the initial voltage V; at the output of the electrical transformer TFM and a voltage value to be reached in accordance with the operating order, the regulator REG can determine a voltage variation to be reached by the CV converter.

[0063] The adjustment commands are in particular determined according to the desired operating mode for the DS device, for example between a step-by-step operating mode and a continuous operating mode. Such an operating mode can for example be preconfigured at the level of the regulator REG. Depending on the selected operating mode, the adjustment commands can control different voltage transitions and / or different primary voltage values ​​V i to be reached by the CV converter. The operating mode can be selected according to a degree of precision expected from the DS device.For example, a step-by-step operating mode of the DS device may allow the regulated voltage Vr at the output of the DS device to be maintained within a standard voltage margin (or interval) (typically, between plus or minus a percentage of a normative voltage value), while a continuous operating mode may allow the regulated voltage Vr at the output of the DS device to be maintained at a given precise value (with a lower degree of error).

[0064] The adjustment orders are thus determined to reach a given switching state of the different switches, corresponding, according to the last data measured in the electrical circuit, to a primary voltage Vi to be reached at the output of the CV converter.

[0065] The adjustment orders are also determined so as to indicate the sequence of switching to be carried out by the switches in order to reach the expected primary voltage Vi. In other words, the adjustment orders indicate the switching action of each switch and the instant (absolute or relative to another switching action) of triggering of the switching action.

[0066] The triggering time of the switching action (or more generally of the switching sequence) can be determined in the adjustment orders as a function of measured data (for example, as a function of the intensity of the current Ir, the switching sequence being for example triggered at zero current, that is to say when the intensity Ir is substantially zero and changes sign). The triggering time of the switching action (or more generally of the switching sequence) can also be determined in the adjustment orders as a function of a modulation ratio a, for example between -1 and 1.

[0067] The adjustment orders take into account in particular the type of switching to be carried out by each switch so that the switching sequence has minimal losses and / or disturbances. Thus, the adjustment orders are determined so as to favor soft (or natural) switching over hard switching (when possible). The implementation of soft switching depends in particular on the intensity of the current Ir, the current switching state of the different switches, as well as the desired transition (i.e., the current value of the primary voltage Vi and the expected value of the voltage Vi).

[0068] Thus, the content of the adjustment orders can take into account the operating mode of the device DS, the value of the initial voltage V;, the intensity of the current Ir, the delay or the advance of the current Ir on the initial voltage V;, the current switching state of the different switches, the current value of the primary voltage Vi and the expected value of the primary voltage Vi (in other words, the desired voltage transition), a change of sign of the value of the current Ir and / or a modulation ratio a.

[0069] In a step 320, the adjustment commands are received by the CV converter and a switching sequence associated with such adjustment commands is triggered. The switching sequence may correspond to a succession of switching actions (for example, the opening or closing of the transistor associated with a switch) to be carried out by each switch at times indicated in the adjustment commands.

[0070] At a step 330, a primary voltage Vi is obtained at the output of the converter CV. The primary voltage V; is obtained following the switching sequence operated by the different switches of the different switching switch blocks S1, S2, S3, S4, in accordance with the adjustment orders issued by the regulator REG.

[0071] In one embodiment, the primary voltage Vi obtained at the output of the CV converter can take a finite and distinct number of values.

[0072] In a first embodiment, the primary voltage Vi obtained at the output of the CV converter can take three values ​​from: the value of the initial voltage (i.e., Vi = Vi), the opposite value of the initial voltage (i.e., Vi = - V;) and a zero value (i.e., Vi = 0 volts). Such a first embodiment can in particular correspond to a first operating mode called "by notches" of the DS device. The switching sequence operated by the different switching switch blocks S1, S2, S3, S4 can then allow four distinct transitions with respect to a current switching state of the switches: a transition from Vi = V; to Vi = 0 volts, a transition from Vi = 0 volts to Vi = Vi, a transition from Vi = -V; to Vi = 0 volts and a transition from Vi = 0 volts to V! = - Vi.

[0073] For example, in the first embodiment, if obtaining a primary voltage Vi = Vi is expected, the adjustment orders issued by the regulator REG in step 310 can control, in step 320, the activation (i.e., the opening) of the switches (Ci, Di), (Cr, Di ) of Si and (C4, D4) and (C4-, D4 ) of S4. If obtaining a primary voltage Vi = - Vi is expected, the adjustment orders issued by the regulator REG in step 310 can control the activation (i.e., the opening), in step 320, of the switches (C2, D2) and (C2-, D2 ) of S2 and (C3, D3), (Cy, D3 ) of S3. If obtaining a primary voltage Vi = 0 volts is expected, the adjustment orders issued by the regulator REG in step 310 can command, in step 320, the joint activation (i.e., the opening) either of the switches (Cb DJ, (Cr, Dr), (C2, D2) and (C2-, D2 ) of Si and S2, or of the switches (C3, D3), (Cy, D3 ), (C4, D4) and (C4-, D4 ) of S3 and S4.

[0074] In a second embodiment, the primary voltage Vi obtained at the output of the CV converter can take two values ​​from: the value of the initial voltage (i.e., Vi = VO and the opposite value of the initial voltage (i.e., Vi = - V;). Such a second embodiment can in particular correspond to a second operating mode called “continuous” of the DS device.

[0075] For example, in the second embodiment, the switching sequence may allow modulation of the initial voltage V; so as to obtain a primary voltage Vi called modulated towards Vi = V; or Vi = - V;. For this, the adjustment commands issued in step 310 may comprise one (or more) value(s) of the modulation ratio a. For example, a positive value of the modulation ratio a (eg, 0 <= a <= 1, <= corresponding to “less than or equal”) makes it possible to increase the primary voltage Vi while a negative value of the modulation ratio a (eg, -1 <= a <= 0) makes it possible to decrease the primary voltage Vi. The modulation implemented by the CV converter may then be implemented by a switching sequence dependent on the initial voltage Vi. For example, if the initial voltage V; is positive (respectively negative), the switching sequence may control the closing switches (Cr, Dr), (C2-, D2), (C3-, D3) and (C4-, D4) (respectively switches (Ci, DJ, (C2, D2), (C3, D3) and (C4, D4)); modulation is then implemented by varying the switching state of switches (Cb DJ, (C2, D2), (C3, D3) and (C4, D4) (respectively switches (Cr, Dr), (C2-, D2), (C3-, D3) and (C4-, D4)).

[0076] In particular, in such a second embodiment, the primary voltage Vi can be expressed, over a switching period of the switches of the CV converter, by: V! = a * Vi, where a is the modulation ratio, a being able to be between -1 and 1.

[0077] The switching period may for example be of the order of 40 microseconds (ps).

[0078] In a step 340, a secondary voltage V2 is obtained at the output of the coupling transformer TFMC from the primary voltage Vi according to a predefined transformation ratio of the coupling transformer TFMC. Such a transformation ratio can be defined according to the granularity or according to expected setting notch values ​​of the device DS. Such a secondary voltage V2 is in particular injected in series with respect to the initial voltage V; at the output of the electrical transformer TFM.

[0079] At a step 350, a regulated voltage Vr at the output of the device DS is obtained at the loads. In particular, the regulated voltage Vr can be expressed by the sum of the initial voltage V; and the secondary voltage V2: vr = Vi + v2

[0080] In particular, depending on the operating mode operated by the DS device, the regulated voltage Vr output by the DS device at the loads can take several possible values. For example, if the DS device operates in a step operating mode, the regulated voltage Vr can take only three values ​​from: Vr= (1+ X %)*Vi Vr= (1- X %)*Vi, or vr= Vi, where X% is the transformation ratio of the coupling transformer TFMC.

[0081] In another example, if the DS device operates in a continuous operating mode, the regulated voltage Vr can take a plurality of values ​​between two extreme values, namely: (lX%)*Vi <= Vr<= (l+X%)*Vi, where X% is the transformation ratio of the coupling transformer TFMC.

[0082] The voltage adjustment device DS then makes it possible to regulate the voltage at the loads, in particular by adding (i.e., in series) a secondary voltage V2 (which can be positive, zero or negative) at the initial voltage V; at the output of the electrical transformer TFM.

[0083] In particular, the DS device can operate according to several distinct operating modes, which makes it possible to adapt the degree of precision of the voltage adjustment provided by the DS device. Two examples of embodiments of the voltage adjustment by the DS device corresponding to two distinct operating modes are described below. First example of realization

[0084] In a first exemplary embodiment, the voltage adjustment device DS is configured to operate according to a so-called notch operating mode.

[0085] In such a notch operating mode, the adjustment orders issued by the regulator allow transitions so that the primary voltage Vi can vary in notches according to three values, -V;, 0 and V;, which makes it possible to obtain a regulated voltage Vr in notches (1- X %)*Vi5 Vr= V; or (1+ X %)*V; respectively, the difference between each notch depending on the transformation ratio X% of the coupling transformer TFMC.

[0086] The adjustment orders are notably issued so that the switching sequence can be carried out at the zero crossing of the current at the primary DN of the coupling transformer TFMC, that is to say when the current at the primary DN is substantially cancelled.

[0087] In particular, the adjustment orders are issued so as to limit losses and disturbances in the electrical circuit when possible. This limitation is particularly possible when the switching sequences are operated in soft (or natural) switching. In particular, when the current Ir lags behind the initial voltage Vi, the following switching operations can be carried out in soft switching: from Vi = V; to Vi = 0, from Vi = 0 to Vi = -V;. When the current Ir leads the initial voltage V;, the following switching operations can be carried out in soft switching: from Vi = 0 to Vi = Vi, from Vi = -Vi to Vi = 0.

[0088] Figures 4, 5, 6, 7, 8 and 9 illustrate a detailed example of a switching sequence according to the notch operating mode. The power lines in bold represent power lines in which an electric current flows.

[0089] With reference to [Fig.4], a current state of the electrical circuit and the DS device is considered. The electrical circuit data are as follows: the current I is behind the initial voltage V, the current I is negative and will change sign by passing through a current of zero intensity (i.e., at zero current) and the primary voltage Vi at the output of the CV converter is zero. The current switching state of the CV converter switches is as follows: the switches (Cb DJ, (Cr, Dr), (C2, D2) and (C2-, D 2 ) of the switching switch blocks Si and S2 are open and the switches (C 3, D3), (C3-, D3), (C4, D4) and (C4-, D4) of the switching switch blocks S3 and S4 are closed.

[0090] The switching sequence illustrated in Figures 4 to 9 may for example be operated over a switching period of 40 microseconds (ps). Such a switching period may depend on the switching speed of the switches of the switching switch blocks Sb S2, S3 and S4 and / or on the period of the network current signal Ir. Such a switching period may also be chosen as a function of the accuracy of the measured signals and / or of targeted safety margins. More generally, the switching period may be less than 100 microseconds. The switching period may also correspond to a fraction of the network period.

[0091] In particular, as detailed below, the switching of the switches of the switching switch blocks S1, S2, S3 and S4 are placed on either side of the zero crossing of the network current Ir.

[0092] Referring to [Fig.5], the first and second steps of the switching sequence are illustrated. In a first step, when the current Ir is negative but close to zero (e.g., at 10 ps after the start of a switching period), the switch (C2-, D2) closes (i.e., transistor C2- is closed). In a second step, when the current Ir is substantially zero without change of sign (or Ir ~ 0) (e.g., at 20 ps after the start of a switching period), the switch (C4, D4) opens (i.e., transistor C4 is activated).

[0093] Referring to [Fig.6], the switch (C2-, D2) is closed and the switch (C4, D4) is open. The internal current Icv within the CV converter continues to flow through the diode D4.

[0094] With reference to [Fig.7], as soon as the intensity of the network current Ir changes sign (Ir ~ 0+), the network current Ir and the internal current Icv within the CV converter change direction, as illustrated in [Fig.7]. The internal current Icv then passes through diode D2 and causes diode D4 to block. This then results in the appearance of a negative primary voltage Vi = -V; at the output of the CV converter.

[0095] With reference to [Fig.8], the third and fourth steps of the switching sequence are illustrated. In a third step, when the intensity of the network current Ir is strictly positive (for example, at 30 ps after the start of a switching period), the switch (C2, D2) closes (i.e., the transistor C2 closes). In a fourth step, at the end of the switching period (i.e., at 40 ps after the start of a switching period), the switch (C4-, D4) opens (i.e., the transistor C4- opens).

[0096] With reference to [Fig.9], this then results in a new switching state of the switches of the CV converter, so that a new negative primary voltage Vi is obtained at the output of the CV converter.

[0097] The switching sequence illustrated by figures 4 to 9 then allows a transition from a state Vi=0 to Vi=-Vi by a smooth switching sequence. Second example of realization

[0098] In a second exemplary embodiment, the voltage adjustment device DS is configured for a so-called continuous operating mode.

[0099] In such a continuous operating mode, the adjustment orders issued by the regulator allow an increasing or decreasing linear modulation of the primary voltage Vi so that the primary voltage Vi can vary linearly between two extreme values, -V; and V;, which makes it possible to obtain a regulated voltage Vr varying between (1X%)*Vi and (1+X%)*V; respectively, the difference between the extreme values ​​depending on the transformation ratio X% of the coupling transformer TFMC.

[0100] The adjustment orders are notably issued according to the primary voltage Vi targeted. Thus, the primary voltage Vi is zero when the switches (Ci, DJ, (Cr, Dr), (C2, D2) and (C2-, D2 ) operate the same command (i.e., switching order), opposite to that operated by the switches (C3, D3), (C3-, D3 ), (C4, D4) and (C4-, D4 ). Furthermore, the primary voltage Vi is non-zero when the switches located diagonally from each other in the figures (for example (Ci, Di), (Cr, Dr) on the one hand and (C4, D4), (C4-, D 4 ) on the other hand) operate the same command (i.e., switching order) at the same time.

[0101] In particular, in the continuous operating mode, filtering can be added at the FE input and FS output of the CV converter, as illustrated in [Fig.6]. Indeed, since the switching sequences can be operated at non-zero current according to forced switching, the addition of an FE input filter and an FS output filter, for example of the passive LC type, makes it possible to limit the harmonic disturbances linked to forced switching (in voltage at the loads and in current at the TFM electrical transformer).

[0102] Figures 11, 12 and 13 illustrate examples of switching sequences in such forced switching in the continuous operating mode. The power lines in bold represent power lines in which an electric current flows.

[0103] With reference to [Fig. 11], a current state of the electrical circuit and the device DS is considered. The data of the electrical circuit are as follows: the initial voltage V; is strictly positive and the primary voltage Vi is zero. The current switching state of the switches of the converter CV is as follows: the switches (Cb DJ, (Cr, Dr), (C2, D2) and (C2-, D2 ) of the switching switch blocks Si and S2 are open and the switches (C3, D3), (C3-, D3 ), (C4, D4) and (C4-, D4 ) of the switching switch blocks S3 and S4 are closed.

[0104] With reference to [Fig. 12], the primary voltage Vi will be strictly positive if the switches (Ci, Di), (Cr, Di ), (C4, D4) and (C4-, D4 ) are closed and (C2, D2), (C2b D2), (C3, D3) and (C3-, D3 ) are open.

[0105] With reference to [Fig. 13], the primary voltage Vi will be strictly negative if the switches (C2, D2), (C2b D2 ), (C3, D3) and (C3-, D3 ) are closed and the switches (Ci, Di), (Cr, Di ), (C4, D4) and (C4-, D4 ) are open.

[0106] The resulting value of the primary voltage Vi then depends on the value of the modulation ratio a (between -1 and 1, or -100% and 100%), with: Vi = a * V; over a switching period (for example over a period of 40 ps).

[0107] In a particular embodiment of the continuous operating mode, the modulation ratio a can be between 0 and 1, and the increasing or decreasing modulation of the primary voltage Vi is made at the zero crossing of the current Icv at the output of the CV converter. Such a particular embodiment then makes it possible to carry out switching sequences according to soft switching, so as to limit disturbances to the electrical circuit. In such an embodiment, the increasing or decreasing modulation of the primary voltage Vi can be implemented on a first set of switches achieving the modulation ratio, such a first set of interruptions switching according to hard switching.The remaining switches allow to select the type of modulation (increasing or decreasing) and such switches can then switch according to a soft switching, when the modulation is implemented at the zero crossing of the current Icv at the output of the CV converter. List of reference signs

[0108] DS: voltage adjustment device CV: converter TFMC: coupling transformer REG: regulator TFM: electrical transformer DN: primary of the coupling transformer (at the converter output), Vi: initial voltage Vi: primary voltage V2: secondary voltage Vr: regulated voltage Ir: network current Icv: internal current in the converter Si, S2, S3, S4: switching switch blocks (Cb DJ, (Cr, Dr), (C2, D2), (C2b D2), (C3, D3), (C3., D3), (C4, D4) (C4b D4): inter- breakers Ci, Ci-, C2, C2', C3, C3', C4, C4-: transistors Di, Dr, D2, D2, D3, D3, D4, D4': antiparallel diodes X%: transformation ratio of the coupling transformer, a: modulation ratio.

Claims

Claims

1. Device (DS) for adjusting an initial voltage at the output of an electrical transformer (TFM) so as to obtain a regulated voltage (Vr), the device (DS) comprising: - a converter (CV) providing a primary voltage (Vi) from the initial voltage (Vi) at the output of the electrical transformer (TFM), - a regulator (REG), arranged to issue adjustment orders to the converter (CV) according to at least one operating mode selected from among several, and - a coupling transformer (TFMC) connected in series, downstream and outside the electrical transformer (TFM) and connected to the converter (CV), the coupling transformer (TFMC) providing a secondary voltage (V2) from the primary voltage (Vi), the regulated voltage (Vr) being obtained from the secondary voltage (V2), said operating modes comprising at least one operating mode called "notch",in which the regulated voltage (Vr) takes a value from among a first voltage, a second voltage and a transition voltage between the first voltage and the second voltage, and a so-called “continuous” operating mode, in which the regulated voltage (Vr) takes a value between the first voltage and the second voltage.,

2. Device (DS) according to claim 1, wherein the device (DS) and the electrical transformer (TFM) are connected via an electrical circuit, and wherein the device (DS) and the electrical transformer (TFM) are two elements distant from each other.

3. Device (DS) according to one of the preceding claims, in which the electrical transformer (TFM) to which the device (DS) is connected is an electrical voltage transformer, the device (DS) being connected to the Low Voltage side of said transformer (TFM).

4. Device (DS) according to one of the preceding claims, in which the regulated voltage (Vr) is obtained by the sum of the initial voltage (V i) and the secondary voltage (V2).

5. Device (DS) according to one of the preceding claims, in which the coupling transformer (TFMC) is configured by a predefined transformation ratio, the secondary voltage (V2) being obtained by the product of the primary voltage (Vi) by the transformation ratio.

6. Device (DS) according to one of the preceding claims, in which the converter (CV) comprises a plurality of semiconductor blocks (Si, S2, S3, S4) forming switching switches, the switching of each of said switches depending on the adjustment orders issued by the regulator (REG), said adjustment orders further depending at least on the initial voltage (V;) and resulting in switching sequences controlling the switching of said switches.

7. Device (DS) according to claim 6, in which the adjustment orders and the switching sequences controlling the switching of said switches depend at least on: - the selected operating mode, and / or - an operating order predefined and stored by the regulator (REG), and / or - a sign of the initial voltage (V;), and / or - a switching state of the switches before said switching, and / or - a zero crossing of the current intensity at the output of the converter (CV), and / or - a phase shift at the input of the converter (CV), and / or - a switching period of the converter (CV).

8. Device (DS) according to one of claims 6 and 7, in which, in the notch operating mode, the switching sequences control a switching of the switches, so that the primary voltage (Vi) takes a value from among: the value of the initial voltage (V; ), a zero value, a value opposite to the value of the initial voltage (Vi), the transition voltage being obtained when the primary voltage (V p) takes the zero value.

9. Device (DS) according to one of claims 6 and 7, in which, in the continuous operating mode, the switching sequences control a switching of the switches according to a modulation ratio between -1 and 1, so that, over a switching period of said switches, the primary voltage (Vi) is expressed by: V! = a * Vi where: - Vi is the primary voltage at the output of the converter (CV), - a is the modulation ratio, - Vi is the initial voltage at the output of the electrical transformer (TFM).

10. Device (DS) according to one of the preceding claims, in which, in the continuous operating mode, the device (DS) further comprises an input filter (FE) and an output filter (FS) of the converter (CV).

11. Method for adjusting an initial voltage (V;) at the output of an electrical transformer (TFM) implemented by an adjustment device (DS), said device (DS) including a converter (CV), a regulator (REG) and a coupling transformer ((TFMC) connected in series downstream and outside the electrical transformer (TFM) and connected to the converter (CV), the method comprising the following steps: - collect an initial voltage (V;) at the output of the electrical transformer (TFM), - obtain adjustment orders based on an operating mode selected from among several, - provide, via the converter (CV), a primary voltage (Vi) from the initial voltage (Vi), - provide, via the coupling transformer (TFMC), a secondary voltage (V2) from the primary voltage (Vi), - obtaining a regulated voltage (Vr) from the secondary voltage (V2), said operating modes comprising at least one so-called "step" operating mode, in which the regulated voltage (Vr) takes a value from among a first voltage, a second voltage and a transition voltage between the first voltage and the second voltage, and a so-called "continuous" operating mode, in which the regulated voltage (Vr) takes a value from among the first voltage and the second voltage.

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