Interconnection method and system to interface an inverter or other electrical equipment with an electric source

Abstract

A method and system for connecting electrical equipment to a power supply network (G) with recognition of the type of electrical network that is associated; the method includes the execution of an algorithm which involves the following operational phases: sampling of the voltages (VRS), (VST) and (VTR) of the power network (G); execution of the Clarke transform at each instant of execution of the algorithm in order to obtain corresponding components of the transformed domain (Vα), (Vβ); control of the absolute value of one (Vβ) of said components of the transformed domain by comparing it with a first pre-established value related to the peak voltage (I) and a second pre-established value (II) to classify the network as three-phase, single-phase in the high power regime or single-phase in the low power regime.

Description

[0001] TITLE

[0002] INTERCONNECTION METHOD AND SYSTEM TO INTERFACE AN INVERTER OR OTHER ELECTRICAL EQUIPMENT WITH AN ELECTRIC SOURCE DESCRIPTION

[0003] The present invention relates to a method and an interconnection system for interfacing an inverter or other electrical equipment having a three-phase, single-phase or three- single-phase input stage to an electrical source.

[0004] Various system solutions are known for detecting the type of power supplied by a network.

[0005] The main class of systems of this type, also called "three-single", is based on the possibility of operating the three phases of a three-phase system in a coordinated manner ("three-single" systems) or independently ("single" systems) with or less than the use of the neutral conductor.

[0006] A first type of system for detecting and locking the three-phase network is the one called PLL (acronym for Phase Lock Loop) which is based on the Clarke transform in conjunction with the Park transform. The transformed three-phase network is made to interact (by product) in a coupling ring with a waveform generated locally in the electronics or in the control software by an apparatus known as a VCO (Voltage Controlled Oscillator); the next aim is to modulate the phase of the waveform output from the VCO in order to cancel the phase error and have it synchronized with the three- phase input network.

[0007] This technique has no drawbacks in the case of a balanced three-phase network but if there are strong imbalances between the phases, the coupling is much less precise and stable.

[0008] Furthermore, it is not effective in the case of a single-phase network.

[0009] In other words, the use of the three-phase PLL as a network type detection algorithm is very problematic and inefficient in a three-single system.

[0010] Another type of system is one that includes a single-phase PLL-type loop for connecting single-phase systems. This system for detecting and connecting the single-phase network (PLL type) is based on the Superheterodyne principle.

[0011] A waveform synthesized locally by the VCO is multiplied with the single-phase voltage to be hooked; the error is then low pass filtered in an appropriate manner until by varying the phase of the VCO a lock is obtained with the input single-phase waveform. This technique makes it possible to hook and detect a single-phase network, which can also be one of the three phase voltages of a three-phase. However, it is not indicated to extrapolate the single connection of one of the three single-phase networks of a three- phase to the other two since the result is not satisfactory in the case of unbalanced networks.

[0012] A further known technique involves comparison with reference values for detecting the type of electrical network. According to this technique, by being able to carry out effective value measurements (RMS) between the terminals of the system or the detector, it is possible to define whether we are in the presence of three-phase (i.e. presence of three similar RMS values) or single-phase (i.e. presence of only one of the three values).

[0013] However, the known techniques indicated above must be related to the construction methods of the converter and, for this reason, it is not possible to identify a general rule that allows their classification.

[0014] W02008 / 074996A1 describes an electrical energy converter arranged to be connected to a source of electrical energy and to condition the energy generated by this source so that it is suitable for being supplied to a network to which the converter is connected. The converter includes an input conversion stage having at least three input terminals and a controller; the controller is designed to configure each of the terminals to accept different types of input.

[0015] Among the purposes of the present invention is to obtain generic operation (i.e. valid in general) for three-single-phase systems even in cases in which resistors are present to allow the discharge of any input filters to the network or in the standard of the devices in production.

[0016] With the method and the system of the present invention a direct connection is possible for three-single systems.

[0017] In the case of three-single systems in single regime, an adapter is usually used that passes only one phase of the system (a phase-phase voltage or a phase-neutral voltage depending on the voltage involved in the three-phase system).

[0018] In three-single systems in single regime, the change of size of the electrical connection is not done automatically, but requires the operator to manually train the system through a configuration because the use of a single-phase system requires a higher level of current high and in any case different operating voltage thresholds. The proposed invention allows the operation of recognition and elevation of the power to be carried out in the case of a high power single line automatically without operator intervention (and therefore without accidental errors) by applying a pre-established scheme (and which will be described later with reference to Fig.6).

[0019] The present invention therefore concerns a method and a system which aim to eliminate the drawbacks of the known art.

[0020] This result was achieved, in accordance with the present invention, by adopting the idea of creating a method and a system having the characteristics indicated in the independent claims. Other characteristics of the present invention are the subject of the dependent claims.

[0021] Among the advantages of the invention, the following can be indicated: it is possible to obtain recognition of the power supply network automatically and without operator intervention; the system is not operator dependent; the creation of the system that allows the invention to be implemented is possible with commercial -type components and therefore does not involve particularly high costs for the material or difficult availability. These and further advantages and characteristics of the present invention will be more and better understood by every person skilled in the art thanks to the following description and the attached drawings, provided by way of example but not to be considered in a limiting sense, in which:

[0022] - Fig. l is a diagram which represents, through symbols and block diagrams, a possible example of application of the present invention;

[0023] - Fig. 2 schematically represents a possible example of an adapter (A) that can be used in a three-phase system;

[0024] - Fig. 3 represents the diagram of Fig.1 with the insertion of the adapter of Fig.2;

[0025] - Fig. 4 schematically represents a possible example of an adapter (A) that can be used in a single-phase system at low power (“single low power”);

[0026] - Fig. 5 represents the diagram of Fig.1 with the insertion of the adapter of Fig.4;

[0027] - Fig. 6 schematically represents a possible example of an adapter (A) that can be used in a single-phase system at high power (“single high power”);

[0028] - Fig. 7 represents the diagram of Fig.1 with the insertion of the adapter of Fig.6;

[0029] - Fig. 8 is a schematic representation of elements in the complex plane “aP” whose deduction will subsequently be clear;

[0030] - Fig. 9 is a flow diagram for recognizing the type of network, particularly specialized for a value of M equal to 3; - Fig. 10 is a diagram which represents, through symbols and block diagrams, a possible example of a three-single system powered by a mains electricity with neutral (with 3P+N+earth polarity); and

[0031] - Fig. 11 is a diagram which represents, through symbols and block diagrams, a possible example of a three-single system powered by the electricity mains with neutral (with polarity 3P+N+earth) and with adapter (A) in single to high power (“single high power”).

[0032] As previously expressed, the solution covered by the document is a generic interconnection system for interfacing an inverter or generic electrical equipment whose input stage is three-phase, single-phase or three-single-phase to an electrical source. The electrical solution is made up of the following elements integrated together:

[0033] - Adapter or series of industrial adapters for standard electrical sockets

[0034] - Extension or series of extensions appropriately made for this purpose

[0035] - Algorithm for recognizing the type of electrical network present at the input

[0036] - Circuit for measuring the voltage of the phases entering the apparatus

[0037] Referring to the attached drawings, in particular to Fig.1, an inverter or generic electronic equipment aimed at energy conversion (for example an AC / AC inverter or an AC / DC converter) is provided with an input stage which is interface to a three-phase and / or single-phase electrical network system (indicated with S in the principle diagram of Fig.1).

[0038] For simplicity, from now on we will consider a three-single-phase universal type input system, which presupposes that the electrical equipment is capable of operating with both a three-phase and single-phase network, with different power and current deratings.

[0039] The electrical equipment draws power from a generic three-phase delta type electrical network (G); with appropriate modifications, the reasoning can also be adapted to star electrical networks with neutral.

[0040] The power is conveyed to the equipment not directly but through a passive adapter (A) which will be better described later.

[0041] Furthermore, an analysis system of the electrical network conveyed by the adapter is provided, indicated with the letter (D), which applies the algorithm according to the present invention to produce an n-tuple of data relating to the type of electrical network detected (indicated with the vector T of dimension N). The analysis system (D) can be external to the network system (S) of the electrical equipment or internal to it. The output signals (T) can be used by the system (S) to apply appropriate fault / power derating / current derating rules depending on the type of electrical network recognized. Inside the network system (S) or the recognition system (D) there are resistors for polarization and anchoring of the value voltage (Y) placed between the three input terminals (R, S, T) of (G '). With (G1) the portion of the network separated from the network (G) by the adapter (A) is indicated; the resistors have equal values, but, as will be analyzed later, this is not a necessary condition for the validity of the algorithm recognition, which is tolerant to the productive spread of the resistance value that occurs in normal implementation applications of the system.

[0042] The recognition algorithm is supported by a processor or other similar device capable of housing software / firmware, preferably placed inside the recognition system (D) or connected to it.

[0043] The present invention will be described below from a general mathematical point of view.

[0044] Suppose that the power supply network (G1) seen by the system (S) after applying the transformations (described below) of the adapter (A) is of the three-phase delta type. For star-delta dualism, the case of a triangle network will be analysed, but the calculations carried out are also applicable to the case of a star network as the various transformations involved (star-triangle and Clarke transformation) are linear functions.

[0045] For reasons of simplicity, compared to the drawing in Fig. l, the tensions are renamed according to the relation (1):

[0046] The Clarke transformation is introduced with maintenance of the amplitudes of the vectors from the time domain "t" to the transformed domain "aPy" according to (2) applied to the triplet of quantities (1) examined by the analyzer D:

[0047] The Park transformation is introduced from the transformed domain “aPy” to the transformed domain “dqO” according to (3) applied to the triplet of quantities (2):

[0048] By hypothesis, the system of source network triples is balanced, so (4) holds at every instant in time:

[0049] In a first analysis, let's assume that we want to operate the system in three-phase mode. The adapter (A) takes on the schematic structure indicated with (Al) in Fig.2.

[0050] With the adoption of the adapter of Fig.2, the system becomes the one represented in Fig.3.

[0051] Condition (4) also applies to the triplet (R, S, T) seen from the system (S) and from (D); furthermore, the lines (R, S, T) are both power and signal, therefore:

[0052] In the time domain we assume the pure sinusoidal voltage triad to simplify the analysis. Since the transformation (2) is linear, the following reasoning also applies to any harmonic components of the voltage and therefore does not make the reasoning lose its validity in the case of a non-ideal network. with: <p = -n (6)

[0053] Apply the transform (2) to the voltage triplet defined by (6). Using sum / difference formulas of sines and the identity (5) which reduces the to 0, we arrive at the following:

[0054] With the value of (|) selected, it turns out that:

[0055] Substituting we would therefore have:

[0056] After examining the system in three-phase mode, the system is analyzed with singlephase operation in a low power regime (for example 3kW, which for convenience we will define as low power regime).

[0057] The adapter (A) takes on the structure (A2) shown in Fig.4.

[0058] With the adoption of the adapter in Fig.4, the system becomes the one represented in Fig.5.

[0059] Since the terminal (T) of the system (S) and system (D) becomes floating (i.e. not connected) with respect to the power, the value resistors (Y) create a three-phase network with virtual neutral.

[0060] The voltage is also applied to the ends of a series of two resistors of value Y, which therefore creates the voltages and through a resistive divider where the two voltages have the same value. In reality, the resistive divider with generic coefficient is considered as a deviation from the theoretical value of equality could occur due to production tolerances and spreads.

[0061] The two previous conditions translate into: but normally: « 1 (10)

[0062] By replacing the second member of (10) in the first member with an appropriate change of sign, we obtain:

[0063] From there:

[0064] Furthermore, the first member of (10) can also be rewritten as:

[0065] Vr ~VRT=—VRR— VST+ VTR= -VRS(13)

[0066] Calculate by applying (2):

[0067] Calculate Vpby applying (2) and using (12) appropriately: ~VTR) , using the second member of (10), we obtain:

[0068] Continuing, using (12) in (15), we will obtain:

[0069] Looking at Fig.5, it is clear that VRSis a single-phase voltage of the type

[0070] =p sin(c ) which, when replaced with the pair (14) and (16), leads to:

[0071] In a third analysis, suppose that the system is operated in single-phase mode in a high power regime (for example 6kW, which for convenience we will define as high power regime).

[0072] The adapter (A) takes on the structure (A3) of Fig.6:

[0073] With the adoption of the adapter in Fig.6, the system becomes the one represented in

[0074] Fig.7.

[0075] Since terminal (T) and (S) of system (S) and system (D) are short-circuited to each other, the voltage VSTbecomes 0 at any instant in time.

[0076] Substituting this condition into (5) always results that VTR= -VRSin every instant of time.

[0077] The voltage is a single-phase voltage of the type VRS

[0078] Substituting these two considerations into (2), we have:

[0079] Therefore, expressing (18) in the time domain we obtain:

[0080] It is to be noted how the situation of this last case can be expressed according to the second member of (10) by setting Q=0.

[0081] So, in fact, the high power adapter can be described in the low power framework by making the hypothesis that the resistance connecting the phases (S) and (T) has a much smaller value than that connecting the phases (R) and (T), effectively causing the resistive divider created to be unbalanced towards the voltage (TR).

[0082] In practice, the system in question can include three adapters (Al, A2, A3) suitable for connecting a power supply network (G) to a portion of the network (G1) to which an equipment (S) is connected, respectively in three-phase mode (Al), single-phase in low power mode (A2) and single-phase in high power mode (A3).

[0083] In other words, the system may include three adapters (Al, A2, A3) designed to connect a power supply network (G) to a portion of the network (G1) to which equipment (S) is connected.

[0084] The first adapter (Al) is provided with three input connections (2R1, 2S', 2T') connected to three phases (R1, S', T') of said network (G) and three output connections ( 2R, 2S, 2T) connected to three phases (R, S, T) of said network portion (G1), in which the three input connections (2R1, 2S', 2T') of the adapter (Al) they are neatly connected to the three output connections (2R, 2S, 2T).

[0085] The second adapter (A2) is provided with three input connections (2R1, 2S', 2T') connected to three phases (R1, S', T') of said network (G) and three output connections (2R, 2S, 2T) connected to said network portion (G'), wherein the two of said input connections (2R', 2S') are neatly connected to the two output connections (2R, 2S), and the third input connection (2T') is not connected.

[0086] The third adapter (A3) is provided with three input connections (2R', 2S', 2T') connected to said network (G) and three output connections (2R, 2S, 2T) connected to said network portion (G'), in which one of said input connections (2R') is connected to the corresponding output connection (2R), the second input connection (2S') is connected to the second and third output connections (2S, 2T ) and the third input connection (2T') is not connected.

[0087] Wanting to summarize the mathematical forms in the cases under consideration, it is possible to define the following summary table, with the form of the transformed domain "aPy" of the various cases:

[0088] Table 1

[0089] Where: Vp... Peak voltage of the first mains harmonic

[0090] Q . . . Ratio between the phase bias resistances RS and RT

[0091] Since in the various cases the y component is equal to zero, the representation of the equations summarized in Table 1 can be limited to the "aP" plane by verifying the position of the extremity of the vector ray with respect to the time variable t. It is sufficient to change the description regime from the Cartesian coordinates “aP” to the polar coordinates “r9” according to the following:

[0092] Apply the transformation (20) to the three various cases (two in reality, having verified that (19) is a particular case of (17)). Relative to the radius vector in the three-phase case, by applying (20) to (9), we obtain the circular representation of the phasor diagram according to the Park transform (3):

[0093] (21) describes a circle with center (0,0) and width equal to the peak of the three-phase network which is crossed by the vector ray with an angular velocity equal to the pulsation of the electrical frequency.

[0094] Relative to the radius vector in the single-phase case, applying (20) to (17), we obtain the representation:

[0095] (22) describes a straight line whose angle with respect to the a axis does not vary over time and depends exclusively on the coefficient ; the ray vector moves along this straight line over time.

[0096] In the special case of the high power type adapter, where Q=0:

[0097] (23) is a straight line inclined by 30° positive with respect to the a axis inscribed inside

[0098] 2 the circle with center (0, 0) and radius —j=VP.

[0099] In the particular case of the balanced low power type adapter, where =1 :

[0100] (24) is a straight line that coincides with the a axis and is inscribed inside the

[0101] 2 circumference with center (0,0) and radius ^j=VP•

[0102] Some important observations can be made regarding (22) regarding another limiting case and non-ideal cases.

[0103] The limiting case in which +<x> concerns an extreme unbalance of the polarization resistors in the case of single low power and is to be understood as a case of fault in which the resistance between S and T tends to be open. In this case, (22) becomes:

[0104] (25) is a straight line inclined by 30° negative with respect to the a axis inscribed inside

[0105] 2 the circumference with center (0,0) and radius —j=Vprepresented in Fig.8.

[0106] In the case in which has intermediate values, a bundle of lines passing through the origin (0, 0) is obtained, all inscribed in the circumference with center (0, 0) and radius angles in the bundle -30°-^ +30°.

[0107] In the case of real non-ideal implementation, given that the three resistors have similar values in non-fault situations, a reasonable limit value M can be established above which the ratio does not go. For example, in an application in which the three Ys are sized the same, due to mismatches and non-uniform operating conditions (i.e. aging, temperatures, ...) M=3 can be considered a more than satisfactory value.

[0108] This choice generates two limit lines that delimit the bundle of lines that contains all the trajectories of the vector rays that the single low power condition describes during the spread of the production parameters of the resistances, which respectively correspond to the conditions:

[0109] Of these two limit lines, we consider the one corresponding to O2and look for the coordinates of the point P in the “aP” domain in which the line intercepts the inscribing circumference of radius which is obtained when sin((yt) = 1 in (17):

[0110] For convenience it is also possible to find the point Q in the “aP” domain in which the 2 straight line intercepts the inscribing circumference of radius Vp, which is obtained when in (19) sin((yz) = l :

[0111] The various equations of interest are graphically represented in Fig.8 in the complex “aP” plane.

[0112] Using Fig.8 and the various equations it is possible to highlight the following relationships:

[0113] 1. In the case of single high power, the component Vpalways remains lower than the value

[0114] 2. In the case of single low power, in real precautionary conditions with M = 3, the component V„ always remains lower than the value — =Vp« 0, 288U, p 2 3

[0115] 3. In the case of three-phase, there are moments in which the component Vphas a value greater than or equal to

[0116] These observations lead to the algorithm represented by the flow diagram in Fig. 9 (which has been adapted for M=3, but can be reformulated in a similar way for any value of the coefficient M).

[0117] The algorithm involves the sampling of the three voltages , VSTand VTR, and the execution of the Clarke transform (2) at every instant of execution of the algorithm. The absolute value of the component Vpis then checked and if it exceeds the value « 0,577Fp over time, then the network can be classified as three-phase. If the absolute value of the component Vpdoes not exceed ~ -, 5'1TVPbut exceeds « 0, 288Fp then the network will be single high power. If the absolute value of the component Vpdoes not exceed « 0, 288Fp then the network is single low power.

[0118] The advantage of the algorithm lies in that it does not require the calculation of the pulsation co (linked to the network period) in order to work, as long as the observation window is long enough to take at least a quarter of the period of the waveform. This condition can be easily satisfied by knowing the typical frequency of the networks to be analysed, typically between 45 Hz and 70Hz.

[0119] A simple prerogative to achieve is the determination of the peak VPthat can be easily achieved with a maximum modulus operation during the observation period of the algorithm itself.

[0120] The ideal is therefore to have the algorithm operate in at least two network cycles: in the first it is possible to detect Vpand in the second to apply the recognition algorithm after verifying the conditions previously expressed.

[0121] From a theoretical point of view, the algorithm has very high convergence speeds,

[0122] . . , T 7 . , requiring a minimum execution time equal to — = — in order to converge, carrying 4 2co out both the detection of the peak Vpand its comparison with the quantities

[0123] With reference to the flow diagram of Fig.9, the method in question therefore involves the operational phases described below through the execution of an algorithm starting from an initial starting phase (indicated by KO) and ending with a final phase (indicated by K4).

[0124] There is an initial sampling of the voltages (VRS), (VST) and (VTR) of the power network (G), indicated by the block (KI), followed by the execution of the Clarke transform at each instant of execution of the algorithm in so as to obtain corresponding components of the transformed domain (Va), (VP) (see block K2) and the calculation of Vp in times multiples of — (block K3).

[0125] Subsequently, the calculation of the absolute value of one (Vp) of said components of the transformed domain is performed by comparing it with a first pre-established value

[0126] 1 related to the peak voltage (~ / =VP) to classify the network as: 3 - three-phase (TR block) if said absolute value is greater than or equal in time to said first pre-established value ( -= Vp); or 3

[0127] - single-phase in high power regime (MH block) if said absolute value is less over time

[0128] 1 than said first pre-established value ( -j= VP) and greater than or equal to a second pre- 3 established value

[0129] - single-phase in low power regime (ML block) if said absolute value is lower in time

[0130] 1 than said first pre-established value ( -F Vp) and lower than said second pre-established 3 value

[0131] In practice, the present invention provides an algorithm capable of detecting the type of network for three-single networks with or without neutral.

[0132] The description made previously takes as its basis a three-phase system without neutral from which a single-phase network is then derived in low power or high power mode depending on the type of adapter connected to it.

[0133] This is valid for a three-phase 230V-32A system from which a single-phase 230V - 16A or 230V-32A network is thus derived.

[0134] The solution in question is also applicable to three-phase systems with neutral like the one represented in Fig.10 where for convenience and simplification the earth conductor is not shown (which is mandatory for safety).

[0135] The simple example is a three-phase 400V-32A from which a single-phase 230V - 16A or 230V-32A network is derived in this way as schematically represented in Fig.11, in which the adapter (A4) diagram is explained with the internal connections (excluding the safety earth conductor which, as previously mentioned, is mandatory).

[0136] It is also important to underline that the detection algorithm is independent of the presence of the neutral.

[0137] In fact, the mathematical framework and the related formulas and algorithms remain valid since for the detection system (D) the voltages that are sampled in (R / S / T) are independent of whether the adapters address voltages referring to the neutral or between phases.

[0138] This aspect is immediately evident by comparing Fig.11 (three-phase system with neutral in single high power regime) and Fig.7 (three-phase system without neutral in single high power regime). Obviously ,the quantities have different numerical values depending on the two cases, especially in the value of the peak Vpbut the application of the algorithm of the present invention and the relative position of the various straight lines within the same regime (i.e. with or without the neutral) remains the same.

[0139] With reference to what was expressed previously regarding the adapter (A) for single high power systems and with the help of Fig.11, the adapter allows the detection system (S) and the detection system (D) to recognize the fact of being connected to a singlephase source of high current (e.g. 32 A) without the need to train / configure the system S itself manually or using alternative techniques of the prior art (e.g. auxiliary contacts, minimum relay, ....).

[0140] With particular reference to the example in Fig.11, the system in the case of a network (G) equipped with a neutral (N) can include a fourth adapter (A4) which is provided with three input connections (2R1, 2S', 2T') connected to said network (G) and three output connections (2R, 2S, 2T) connected to said portion of network (G1). One of said input connections (2R1) is connected to the corresponding output connection (2R), the second input connection (2S1) and the third input connection (2T1) are connected to said second and third connections output (2S, 2T) via a fourth connection (2N) connected to the neutral (N).

[0141] The invention can be used in an electrical system (S) and / or (D) in double single mode (without neutral). In practice, it is possible to build an electrical system S (with D integrated or external to it) which, through the presence of a set of three adapters A, allows three operating modes to be obtained, respectively:

[0142] - three-phase: Three-phase adapter (A) with the algorithm of the invention;

[0143] - single low power: Adapter (A) single low power with the algorithm of the invention;

[0144] - single high power: Adapter (A) single high power with the algorithm of the invention. With the present invention it is also possible to create an electrical system (S) (with D integrated or external to it) which, through the presence of the same set of adapters, allows operation even in networks with the presence of the neutral without electrical modifications and / or algorithmic.

[0145] The invention is applicable to an adaptive electrical system (S), with the creation of an electrical system S (with D integrated or external to it) which, through the use of classification signals T (i.e. type of network, type of network single low / high power), current limiting modules and / or internal power / current management thresholds as appropriate. The limitation has the dual purpose of preserving the network or generator that generates the electrical network, the electrical interconnections that transport the electrical power to the S system (i.e. electrical sockets / plugs / cables) and any electrical / mechanical devices powered by the S system ( i.e. inverters / electric motors, ....)

[0146] Advantageously, the algorithm in question is very "light" from a computational point of view compared to the state of the art and has the following advantages:

[0147] - does not require the presence of VCO;

[0148] - does not require the presence of control and / or cancellation loops of the relevant phase;

[0149] - it is independent of the network frequency (if run for a sufficiently long time);

[0150] - does not require an a priori classification of the type of network in order to be applied (i.e. choice between single-phase PLL and three-phase PLL for coupling and classification);

[0151] - does not require the calculation of RMS of various network voltages for the determination of mutual relationships or relative phase shifts.

[0152] Furthermore, advantageously, the algorithm in question has the ability to converge in a minimum time equal to a quarter of the period of the network to be classified.

[0153] This allows a very fast switch between the three-phase and single-phase operating mode to allow the S electronics to manage transients and fast and repeated variations in the electricity grid regime.

[0154] Furthermore, the algorithm object of the invention and the use of the adapters (A) indicated previously do not require a priori knowledge whether we are in three-phase or single-phase regime with / without neutral unlike the PLL rings (used in the prior art) for its applicability.

[0155] In conclusion, it is therefore possible to state that the invention provides a universal approach with no prerequisites to its applicability.

[0156] In practice, the execution details can however vary in an equivalent way as regards the individual elements described and illustrated, without departing from the idea of the solution adopted and therefore remaining within the limits of the protection granted by the following claims.

Claims

CLAIMS1. Method for connecting an electrical apparatus to a power supply network (G) with recognition of the type of electrical network that is associated with it, wherein said electrical apparatus is of the three-phase, single-phase or three-single-phase type and wherein the voltages (Vi), (V2) and (V3) of a power supply network (G) are defined by the voltages (VRS), (VST) and (VTR) in correspondence with the respective phases (R, S, T), method characterized in that it comprises the execution of an algorithm which includes the following operating phases:- voltage sampling (VRS), (VST) and (VTR) of the power supply network (G);- execution of the Clarke transform at each execution instant of the algorithm in order to obtain corresponding components of the transformed domain (Va), (Vp);- control of the absolute value of one (Vp) of said components of the transformed domain1 by comparing it with a first pre-established value related to the peak voltage VP) to 3 classify the network as:- three-phase if said absolute value is greater than or equal over time compared to said first pre-established value (-^VP) or 3- single-phase in high power regime if said absolute value is less in time than said first pre- established value (~i=VPand greater than or equal to a second pre-established value 3 kp); °r- single-phase in low power regime if said absolute value is less in time than said first pre-1 1 established value ( =Vp) and less than said second pre-established value (^f kp).

2. Method according to claim 1, characterized in that after the Clarke transform, the calculation of the peak voltage value (Vp) is performed in times multiple of — .

3. System for connecting an electrical apparatus (S) to a power supply network (G) with recognition of the type of electrical network that is associated, wherein said electrical equipment (S) is of the three-phase, single-phase or three-single-phase type and wherein the voltages (Vi), (V2) and (V3) of a power supply network (G) are defined by the voltages (VRS), (VST) and (VTR) in correspondence with the respective phases (R, S, T), system characterized in that it comprises:- connection means to an electric network (G) comprising one or more adapters (A) connectable to sockets, provided with relative extension, said one or more adapters (A)being intended to receive the power of the network (G) to which it is connected the electrical apparatus;- a device (D) for analyzing the network (G) conveyed by the adapter (A) equipped with a recognition algorithm so as to produce an n-tuple of data (T-N) relating to the type of detected electrical network; wherein said algorithm is provided with means and / or software to carry out:- voltage (VRS), (VST) and (VTR) sampling of the power supply network (G);- the execution of the Clarke transform at each execution instant of the algorithm in order to obtain corresponding components of the transformed domain (Va), (Vp);- checking the absolute value of one (Vp) of said components of the transformed domain by comparing it with a first pre-established value correlated to the peak voltage (-= VP) to classify the network as:- three-phase if said absolute value is greater than or equal over time compared to said first1 pre-established value (~^VP) or 3- single-phase in high power regime if said absolute value is less in time than said first pre-1 established value (- Vp) and greater than or equal to a second pre-established value 3 kp); °r- single-phase in low power regime if said absolute value is less in time than said first pre-1 1 established value ( =Vp) and less than said second pre-established value (^f kp).

4. System according to claim 3, characterized in that it comprises three adapters (Al, A2, A3) apt to connect a power supply network (G) to a portion of the network (G1) to which an apparatus (S) is connected, respectively in three-phase mode (Al), in single-phase in low power regime (A2) and in single-phase in high power regime (A3).

5. System according to claim 4, characterized in that it comprises a fourth adapter (A4) able to connect the power supply network (G) to the portion of the network (G1) to which an apparatus (S) is connected in single-phase mode in high power regime with neutral.

6. System according to claim 3, characterized in that it comprises three adapters (Al, A2, A3) apt to connect a power supply network (G) to a portion of the network (G1) to which an apparatus (S) is connected, in which:- the first adapter (Al) has three input connections (2R1, 2S', 2T') connected to three phases (R1, S', T') of said network (G) and three output connections (2R, 2S, 2T) connected to three phases (R, S, T) of said portion of the network (G1), wherein the three input connections(2R1, 2S', 2T') of the adapter (Al) are orderedly connected to the three output connections (2R, 2S, 2T);- the second adapter (A2) has three input connections (2R1, 2S', 2T') connected to three phases (R1, S', T') of said network (G) and three output connections (2R, 2S, 2T) connected to said network portion (G1), wherein the two of said input connections (2R1, 2S') are orderedly connected to the two output connections (2R, 2S), and the third input connection (2T1) is not connected;- the third adapter (A3) has three input connections (2R1, 2S', 2T') connected to said network (G) and three output connections (2R, 2S, 2T) connected to said portion of network (G1), wherein one of said input connections (2R1) is connected to the corresponding output connection (2R), the second input connection (2S1) is connected to the second and third output connections (2S, 2T) and the third input connection (2T1) is not connected.

7. System according to claim 6, usable in the case of a network (G) provided with a neutral (N), characterized in that it comprises a fourth adapter (A4) which is provided with three input connections (2R1, 2S', 2T') connected to said network (G) and with three output connections (2R, 2S, 2T) connected to said portion of network (G1), wherein one of said input connections (2R1) is connected to the corresponding output connection (2R), the second input connection (2S1) and the third input connection (2T1) are connected to said second and third output connections (2S, 2T) by means of a fourth connection (2N) connected to neutral (N).

8. System according to any claim from 3 to 7, characterized in that said electric apparatus (S) or said analysis device (D) are provided with bias and anchoring resistors of the value voltage (Y) placed between the three terminals of input (R, S, T) of said network portion (G).

9. System according to any claim from 3 to 7, characterized in that said analysis device (D) is inside the apparatus (S).

10. System according to any claim from 3 to 7, characterized in that said analysis device (D) is external to the apparatus (S).

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