High-current programmable electrical power source for testing high-current electrical connectors

Abstract

The invention relates to a high-current programmable electrical power source (1) for testing electrical connectors and conductors, which comprises: a command box (8) for energising and de-energising; a set of power inverter modules (9), which each comprise a DC link formed by a set of capacitors and at least one inductor (14) at each of the two output terminals thereof; a current measurement system (10); a voltage measurement system (11); two output busbars (12); a temperature measurement module; and an interface (7) for communicating with a system for controlling the electrical power source, wherein each first and second inductor (14) of each inverter module is respectively connected to the first and second output busbar (12), which bars allow connection to the element to be tested.

Description

[0001]Programmable high current power source for testing high current electrical connectors DESCRIPTIVE MEMORY FIELD OF THE INVENTION The present invention is developed in the field of high current technology, specifically, it refers to a programmable high current power source for testing high current electrical connectors that allows analyzing their response to the presence of currents higher than the nominal operating values, determine possible points of improvement in their design and construction and certify their quality through transversal international regulations for distribution systems. BACKGROUND OF THE INVENTION In electrical distribution networks, the use of electrical connectors is essential for making electrical derivations and / or connections between electrical devices in order to supply the population with its daily consumption of electrical energy. Due to this, the connectorsElectrical connectors must be properly tested and certified to ensure proper operation, avoiding connection failures that would leave consumers, businesses, and even critical establishments, such as hospitals, without electricity. These electrical connectors can be certified under international regulatory standards such as ANSI C119.0 and UNE 21-021-83, which refer to accelerated thermal aging tests under electrical operating conditions. However, there are no certification centers or institutions in Chile that allow such evaluations to be carried out. On the other hand, expensive and inflexible equipment is used to carry out tests. These equipment cannot be electronically programmed to perform hundreds of cycles automatically. They are limited to direct current or a single specific frequency (50Hz or 60Hz), and they are not capable of maintaining electronically controlled current and adapting to different operating conditions.dynamically to changes in conductor impedance during testing. These restrictions limit its application for connector certification and for the eventual use of new materials and / or shapes of new conductors. This is why it is necessary to design and manufacture an electrical source, based on power electronics, specifically designed for this application. In the state of the art it is possible to find electrical sources for test systems or for testing electronic components. In this regard, mention may be made of document AU2021206550A1, which describes a high current source for a test system for testing an electrical power device, comprising a first plurality of switchable first half-bridges and a second plurality of switchable second half-bridges, which are connected in parallel and through which a test current is redundantly distributed. A control device is designed tocontrolling the first and second half-bridges on the basis of an input signal such that an output signal is generated for the test current, which corresponds to the input signal. applied through a bridge branch between the first switchable half-bridges and the second switchable half-bridges. Another document that may be considered corresponds to document US 3,423,677, which describes a system for automatically performing static or dynamic tests on a multi-lead integrated circuit, comprising a test station comprising a direct current supply; a pulse generator for producing a repetitive pulse waveform; switching means for selectively connecting the direct current supply and the pulse generator to test the sample under various conditions; measuring means connected to the test station for performing dynamic time and amplitude measurements to produce apulse train and a count data signal representing the measurement magnitude and performing static measurements and producing a pulse train signal in which the frequency of the pulses represents the measurement magnitude; data reading means connected to the outputs of the measuring means to count the pulse number; and programmable control means to automatically operate the system to perform programmed measurements. Also mentioned is document MX / a / 2019 / 015334, which discloses a high current source controlled by variable autotransformers for primary current injection into medium voltage switches or reclosers mounted on poles with low internal impedance and easy handling in field tests, which reduces the load impedance and impedance represented by the injection cables, because the high current is generated in the proximity of the equipment under test with electric clamp-type connections of grinding wheels.Solid, toothed, silver-plated components reduce contact resistance, and the injection stage is easy to handle and can be separated by tens of meters from the control stage, both connected by a multi-core cable. Finally, document CO2022007196A1 describes a system based on a high-current source, capable of supplying current levels of up to 65 kA and three-phase voltages of up to 1 kV, for short-circuit testing on low-voltage electrical equipment. The system's high-current source is based on an array of toroidal transformers. The system also has at least one metrology module, low- and medium-voltage bars, a control module, and a protection module. The implementation of the system allows for short-circuit testing for the development of low-voltage equipment, such as switchgear, cells, and transformers. Although they describe differentelectrical sources for carrying out different tests, none of the aforementioned documents provides a programmable electrical source that can supply a current of 2000 A and that said current is controllable from 10 A to 2000 A, both in alternating current of 50 Hz or 60 Hz and in direct current, in addition, without the use of transformers, which introduce non-linearities, limit the operation to a single frequency, and are heavy and bulky elements, for carrying out thermal performance tests on connectors in accordance with the specifications of international regulations, such as ANSI C119.0 and UNE 21-021-83, allowing to expand the range of tests that can be performed. DESCRIPTION OF THE INVENTION The present invention relates to a high current programmable electrical source for testing high current electrical connectors that allows analyzing their response in the presence of currents higher than the nominal valuesof operation, determine possible points of improvement in its design and construction and certify its quality through transversal international regulations for distribution systems. The high-current programmable power supply is designed to supply 2000 A in both 50 Hz or 60 Hz alternating current and in direct current, which makes it possible to carry out thermal performance tests on connectors in accordance with the specifications of international regulations, such as ANSI C119.0 and UNE 21-021-83, allowing to expand the range of tests for products that are used in other countries and even for networks that use direct current, for very relevant applications such as fast charging in electromobility and photovoltaic systems. The power supply includes control means that allow constant current tests to be carried out by setting the current reference and tests adjusted to the ANSI C119.0 standard and the entire operating protocol described inher. To perform these tests, the power supply includes temperature measurement modules in order to carry out thermal monitoring of the electrical connectors being tested and of the electrical conductor that carries the current. In this way, the high-current programmable power supply allows thermal aging and electrical wear tests to be carried out due to overcurrent on an arrangement of electrical conductors and connectors with a nominal current between 10 A and 2000 A peak in AC and a DC current of up to 1540 A, with a maximum output power of up to 5.5 kW, comprising: • A power supply power inlet, which must be connected to a three-phase 380V source between phases, plus neutral and ground; • A main power board that receives power from the power inlet to feed a set of AC / DC power supplies, which deliver power to the components of the power supply, and apower supply of an electrical source control system, where said electrical source control system allows to control the current in real time, program the execution of tests and obtain the information of the tests carried out; • An on / off command box to perform the energization / de-energization of the power and control stages and the emergency stop • A set of power inverter modules that allows to control a current in a range of 10 A to 2177 A peak in effective AC, both in alternating current of 50 Hz or 60 Hz, as well as in direct current up to a maximum of 1540 A, providing sufficient current to carry out the tests, which have a direct current link formed by a set of capacitors and a pair of inductors at their output terminals, allowing to deliver the controlled electrical current in both alternating current and direct current, where each of the currents isdirected to circulate in the arrangement of conductors and electrical connectors arranged in its output terminals and achieve a regulated temperature increase; • A current measuring system and a voltage measuring system to control the output current of the source; • At least one pair of high current inductors for each inverter module of the set of power inverter modules with an inductance of approximately 15 µH to 20 µH, being capable of filtering harmonic components and enabling the implementation of the electrical source control system, each inductor being connected to one of the output terminals of the inverter module at one of its ends and the other to a respective output bar, which allows the connection of the arrangement of conductors and connectors to carry out the thermal performance tests; • A temperature measuring module for measuring temperatures in the electrical source (1), whichtransforms the analog temperature measurement of the thermocouple into digital data to be transferred / transmitted; and • A user interface of the power supply that allows a user to communicate with the power supply control system to program the operating mode and collect measurement data from the tests performed. The power supply is limited by software to deliver DC, 50Hz or 60Hz current. However, its hardware is capable of delivering any frequency, between 0Hz and 100Hz. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a better understanding of the invention and constitute part of this description and also illustrate a preferred embodiment of the invention, where it can be seen that: Figure 1 shows a connection diagram for an arrangement of electrical conductors and connectors, according to an embodiment of the invention. Figure 2A shows a schematic view of the front of theEnglish: high current programmable power supply, according to an embodiment of the invention. Figure 2B shows a schematic view of the rear of the high current programmable power supply, according to an embodiment of the invention. Figure 3 shows the topology of the controlled inverter of the programmable power supply, according to an embodiment of the invention. Figure 4 shows a control diagram of the controlled inverter of the programmable power supply, according to an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION The high current programmable power supply (1) for testing electrical connectors (3A, 3B, 3C, 3D) at high current by performing thermal aging and electrical wear tests due to overcurrent in an arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) with a nominal current between 10 A and 2000 A and a maximum output power of up to 5.5 kW, comprises:• A power supply inlet (4) of the power source, which must be connected to a three-phase 380V source between phases, plus neutral and ground; • A main power supply board (5) that receives power from the power supply inlet (4) to feed a set of AC / DC power supplies (6), which deliver power to the components of the power supply (1), and a power supply board of a power supply control system (7), where said power supply control system (7) allows controlling the current in real time, programming the execution of tests and obtaining information on the tests performed; • An on / off command box (8) to energize / de-energize the power and control stages and the emergency stop; • A set of power inverter modules (9) that allows controlling a current in a range of 10 A to 2177 A peak effective in alternating current of 50 Hz or 60 Hz, and up to 1540 A in alternating currentcontinuous, providing sufficient current to perform the tests, which have a direct current link formed by a set of capacitors and at least one pair of inductors (14) in their output terminals, allowing the controlled electric current to be delivered in both alternating current and direct current, where each of the currents is directed to circulate in the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) arranged in their output terminals and achieve a temperature increase in a regulated manner; • A current measuring system (10) and a voltage measuring system (11) to control the output current of the electrical source (1); • The at least one pair of high current inductors (14) in each inverter module of the set of power inverter modules (9) with an approximate inductance of between 15 µH and 20 µH, being capable of filtering harmonic components and enabling the implementationof the power supply control system (7), each inductor (14) being connected to one of the output terminals of an inverter module at one end and at the other end to a respective output bar (12), which allows the connection to the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) to carry out the thermal performance tests; • A temperature measurement module for measuring temperatures in the power supply (1), which transforms the analog temperature measurement of the thermocouple into digital data to be transferred / transmitted; • A user interface of the power supply (1) that allows communication of a user with the power supply control system (7) to program the operation mode and collect the measurement data of the tests performed. The power supply (1) may further comprise a beacon (13) to indicate to a user the operation of the power supply (1) and that it existsrisk of electrocution in the cables and connectors. In one embodiment of the invention, the AC / DC power supply assembly (6) comprises: a power supply, independent for each inverter module of the power inverter module assembly (9), for converting 220VAC to 24VDC to energize the power stages of the inverter modules of the power inverter module assembly (9); a power supply, independent for each inverter module of the power inverter module assembly (9), for converting 220VAC to 12VDC to energize the electronic stage of the inverter modules of the power inverter module assembly (9); a power supply for converting 220VAC to 24VDC to energize the electronic stage of the current measurement system (10) and the voltage measurement system (11); and a power supply for converting 200 VAC to 5VDC and 12VDC to energize the electronic stage of the control systempower supply (7) that requires dual power supply. In this way, one power supply is used to energize the power stages and one power supply to energize the electronic stage for each inverter module of the set of power inverter modules (9). The power supplies and inverter modules of the set of power inverter modules (9) can be arranged in a vertical arrangement, being arranged in an interleaved manner in the power supply (1), as shown in figures 2A and 2B. Specifically, one power supply is used, in an isolated manner, for each of the inverter modules of the set of power inverter modules (9), separately, which allows to reduce the circulating ripple currents, of frequency equal to the switching frequency, that are generated between the inverter modules connected in parallel, which are inevitable and increase the losses of the equipment, limiting its operation.Reducing the circulating ripple currents, with a frequency equal to the switching frequency, increases the available power of the system for the load. The control board of the power supply control system (7) can be configured to manage the power supply of the set of AC / DC power supplies (6), also comprising an isolation transformer in its input area. The set of power inverter modules (9) allows the current to be controlled in the range of 10 A to 2177 A peak, being limited to a maximum current of 2000 A for safety, in alternating current of 50 Hz or 60 Hz, or in direct current up to a current of 1540 A, which cannot be achieved with a single power electronics module, since there is no topology that can handle 2000 A in alternating current. The safety limitation on the maximum current value is carried out by means of software configuration. The maximum current is sufficient to perform tests inthe largest caliber driver, i.e. 240 mm 2of copper, whose suggested current to reach 100 ° C above ambient temperature is 970 A. In one embodiment of the invention, the set of power inverter modules (9) comprises 11 power inverter modules, where each one controls 198 A peak (140 A rms) in alternating current of 50 Hz or 60 Hz, or 140 A in direct current, where each inverter module comprises: an H-bridge card, which transports the power of the inverter module, comprising a greater amount of copper and includes power transistors, heatsinks, fans and input / output power terminals of the module; 4 Gate-Driver cards to turn the transistors of the power module on and off, being mounted directly on the H-bridge card; a Power-Controller card that receives the power supply (12VDC), optical fiber pulses,conditions the drive signals and indicates the correct or incorrect operation of the module; a set of semiconductors that act as switches to allow the flow of electric current in the system. The use of an H-bridge card allows the modulation of direct and alternating currents in the indicated current range. It must be verified that the Gaste-Driver cards are mounted correctly to avoid the possibility of short-circuiting the power supply that feeds the inverter module and to ensure that the inverter module operates correctly. The semiconductors can be adjusted to modulate a switched voltage at their output terminals, when operating together, in order to regulate the current flowing through them and, consequently, in the output arrangement corresponding to the conductors (2) and electrical connectors (3A, 3B, 3C,3D). The input of each inverter module receives power from the set of AC / DC power supplies (6) and the output of each inverter module is connected in parallel by means of the power inductors (14) to the output bars (12). It should be kept in mind that power semiconductors are primarily used for the intelligent and controlled management of electrical variables such as voltage and current. These devices are thermally limited by the power they can dissipate, which depends on the current they handle and the switching frequency used. Handling high current values ​​(>500 A) with high switching frequencies (>1 kHz) becomes an impractical task for a semiconductor, because the electrical losses are very high and therefore also their temperature, causing destruction of the devices. The application in question is even more challenging,since the system to be tested is simply a conductor, which represents an electrical short circuit for the current source. To control currents under these conditions, frequencies greater than 1 kHz are required. Controlling high current values, with a load that is short-circuited, requires a high switching frequency of the semiconductors. To do the above, in one embodiment of the invention, the set of semiconductors comprises 8 semiconductors, for each module, so that the current from the electrical source (1) can be distributed among several devices, in a coordinated manner, to allow a switching frequency of up to 5 kHz. In this way, it is possible to control high current values. In one embodiment of the invention, the current measurement system (10) comprises a current sensor for each inverter module of the set of power inverter modules (9). In addition,The current measurement system (10) comprises a plurality of current measurement cards with a total number of measurement channels that allow all the sensors to be connected. If the measurement channels of the cards are not connected to any sensor, these must be short-circuited to avoid interference in the current measurement. In one embodiment, each current measurement card is powered with 24VDC and has 8 measurement channels, each with 4-pole connectors (+15VDC / - 15VDC / GND / Measurement referred to GND), and two RJ-45 / UTP type outputs (4 measurements per output). In one embodiment, the current sensor corresponds to the PowerUC HST21 current sensor (±15VDC power supply), which has a measurement range of ±400A instantaneous, 1% error. In one embodiment of the invention,The voltage measuring system (11) comprises a plurality of voltage measuring cards for measuring the potential difference in the inverter modules of the set of power inverter modules (9), the plurality of voltage measuring cards having a total number of measurement channels that allow connecting all the inverter modules of the set of power inverter modules (9). In case the measurement channels of the cards are not connected to any inverter module, they must be short-circuited to avoid their interference in the voltage measurement. In order for the measurement to be carried out, the positive and negative cables are connected at the point where the potential difference measurement is to be carried out, respecting the polarity of the card. In one embodiment, the voltage measuring cards correspond to a card powered with 24VDC and has 4 voltage measurements,which are sent through a single RJ-45 / UTP type output channel, the maximum value that can be measured being ±120V instantaneous. In one embodiment of the invention, the power supply control system (7) comprises: a Carrier card to connect all the components; a communications card with peripherals associated with the communication; at least 2 optical fiber cards, which send the pulses to activate / deactivate: the transistors of the inverter modules of the set of power inverter modules (9), the operation of the inverter modules and the command of the general contactor of the system; and an analog-digital conversion card,which receives the current and voltage measurements from the current measurement system (10) and the voltage measurement system (11) and conditions them for use in the power supply control system (7) of the power supply (1). In the embodiment of the invention in which the power supply comprises a beacon (13), the 2 fiber optic cards are also responsible for sending the pulses to activate and deactivate said beacon (13). For a correct implementation of the power supply (1), power inductors (14) are necessary. However, the power inductors (14) are robust, heavy and very expensive for high current values. In addition, they are not manufactured to handle currents with high frequency ripples, since their losses rise greatly due to the skin effect and losses in their cores. Additionally, commercial inductors for currents greater than 200 A are not found,suitable for handling high ripple current of 5 kHz. Due to the above, in one embodiment of the invention, inductors (14) are manufactured with an air core, avoiding the use of ferromagnetic materials, generating a lightweight and low-cost inductor (14). The inductors (14) are manufactured with 360 strands of electrically insulated wire, each with a section of 0.158 mm, 2 , which supports temperatures up to 125 ° C. In one embodiment of the invention, this configuration for the inductors (14) allows generating a capacity of 170 A and inductance of 17.34 uH for each inductor (14). The power delivered by the electrical source (1) is mainly dissipated in the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) on which the tests are performed, where the resistance of the arrangement and the current passing through it determine the dissipated power as RI 2. As long as said value is below the maximum allowed (5.5 kW), the arrangement can have any length desired. In one embodiment of the invention, the output bars (12) correspond to a high purity copper profile whose ampacity reaches 2000 A rms. In particular, the output bars (12) can be 12 cm wide and 1 cm thick. In one embodiment, the output bars (12) have an L shape, with a vertical section (121) where the inductors (14) are connected and a horizontal section (122) where the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) are connected.The arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) define an output loop (16), being connected to the electrical source (1), by means of the output bars (12), in positive and negative cables, which are connected, respectively, with an input conductor (21) and an output conductor (22), making the output current of the electrical source (1) circulate in the output loop (16). The inductors (14) and the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) are connected to the output bars (12) in perforations made with drill bits, preferably being 6 mm or 8 mm. The cross-sectional area of ​​the output bars (12) must be at least 1000 mm. 2to avoid overtemperatures in said output bars (12). In one embodiment, the electrical source comprises at least two output bars (12) to ensure a proper connection with the inductors (14) and with the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D). In one embodiment of the invention, the temperature measurement module comprises a set of independent temperature measurement modules, each associated with a thermocouple (T), which transform the analog temperature measurement of the thermocouple (T) into digital data to be transferred / transmitted. The set of independent temperature measurement modules comprises a module for measuring the ambient temperature, a module for measuring the temperature of a control conductor (23), and a module for measuring the temperature of each electrical connector (3A, 3B, 3C, 3D) in the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D). In one embodiment,The thermocouples (T) used are type K, with a maximum operating temperature of 500 °C, a measurement accuracy of 1.5 °C, and a measurement resolution of ±0.065 °C. It is important that the thermocouples (T) connected to each independent module are correctly connected to the corresponding element, since incorrect positioning of the thermocouples (T) can lead to irreversible failure and / or destruction of the electrical source. Furthermore, direct contact between the metal of the thermocouple (T) and copper or aluminum must be avoided, as this may cause measurement errors. For a correct arrangement of the thermocouples (T), they must be covered with a material that is electrically insulating and thermally conductive, in order to avoid direct electrical contact with the conductor arrangement (2) and electrical connectors (3A, 3B, 3C, 3D), which may cause measurement errors. The thermocouples (T) must be fixed to the electrical connectors (3A, 3B, 3C,3D) in the area with the smallest cross-sectional area and in the control connector (23), the thermocouple (T) must be completely wrapped and lightly pressed to ensure that it measures the temperature of the control connector (23) and not the temperature of the air around it. The thermocouples (T) cannot be pressed excessively since this produces measurement errors and / or their destruction. In one embodiment, as shown in Figure 1, the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) comprises four electrical connectors (3A, 3B, 3C, 3D) connected in series,wherein: a first electrical connector (3A) has its input connected to the input conductor (21) and its output connected to a first conductor (24); a second electrical connector (3B) has its input connected to the first conductor (24) and its output connected to a second conductor (25); a third electrical connector (3C) has its input connected to a third conductor (26) and its output connected to a fourth conductor (27); and a fourth electrical connector (3D) has its input connected to the fourth conductor (27) and its output connected to the output conductor (22), wherein the second conductor (25) and the third conductor (26) are connected via the control conductor (23) to complete the circuit. The input conductor (21) and the output conductor (22) comprise a first section of length ≥2L and a second section of length L, the control conductor comprising a single section of length L,the first conductor (24) and the fourth conductor (27) comprise a first and second section of length L, and the second conductor (25) and the third conductor (26) comprise a single section of length L. The conductors (2) correspond to a braided or solid type cable that can be made of aluminum or copper. The length L will be defined by the international standards used to carry out thermal aging and electrical wear tests, being for example in the ranges shown in table 1. Table 1: Conductor lengths (distance L) according to ANSI C119.0 Standard (mm, 2). The high current programmable power supply (1) further comprises a cabinet (15), preferably in the form of a parallelepiped with its longer sides arranged vertically, which defines an interior volume that allows housing components of the power supply (1) by arranging them vertically. In one embodiment of the invention, the cabinet (15) comprises a base, in the form of a quadrilateral, from which two parallel vertical walls project, of rectangular shape, on which a cover is arranged, of the same shape as the base, such that on two sides of the base no walls are projected,defining a front access and a rear access to the interior volume of the cabinet (15). The front access may comprise a door to prevent improper contact with the components of the power supply (1) and reduce the risk of accidents. The interior volume of the cabinet (15) comprises an internal shelf structure comprising a plurality of support trays for placing components of the power supply (1). In one embodiment, the components of the power supply may be arranged as follows in the cabinet (15), as shown in Figures 2A and 2B: the power inlet (4) is arranged at the bottom of the left side of the cabinet (15),on the respective vertical wall; the main power supply board (5) is arranged at the bottom of the interior volume of the cabinet (15) to be connected to the power outlet and receive power to feed the AC / DC power supply assembly (6); the AC / DC power supply assembly (6) is arranged in the interior volume of the cabinet (15), above the main power supply board (5) for connection thereto, being in turn connected to the inverter modules of the power inverter module assembly (9), to the current measurement system (10), to the voltage measurement system (11) and to the power supply board of the power supply control system (7), to supply them with power for their operation; the power inverter module assembly (9) is arranged at the top of the interior volume of the cabinet (15),being on the set of AC / DC power supplies (6); the current measuring system (10) is arranged on the right side of the cabinet (15), on the respective vertical wall, at a height that coincides with a part of the interior volume of the cabinet (15) where the set of power inverter modules (9) is located, such that said current measuring system (10) is connected to said set of power inverter modules (9) to perform current measurements of each inverter module; the voltage measuring system (11) is arranged on the left side of the cabinet (15), on the respective vertical wall, at a height that coincides with a part of the interior volume of the cabinet (15) where the set of power inverter modules (9) is located, such that said voltage measuring system (11),is connected to said set of power inverter modules (9) to perform group voltage measurements of the set of power inverter modules (9); the on / off command box (8) is arranged on the right side of the cabinet (15), on the respective vertical wall, in a position below the current measuring system (10), being connected to the main power board (5), to perform the energization / de-energization of the electric source (1); the electric source control system (7) is arranged on the right side of the cabinet (15), on the respective vertical wall, in a position below the on / off command box (8), being connected to the main power board (5), to the AC / DC power supply set, to the set of power inverter modules (9), to the current measuring system (10), to the voltage measuring system (11) and to the arrangement of conductors (2) and electrical connectors (3A,3B, 3C, 3D), to control the current in real time, schedule the execution of tests and to obtain information on the tests performed; and the output bars (12) are arranged at the rear of the cabinet (15), in a position that coincides with the location of the set of power inverter modules (9), to connect with the inductors (14) of each inverter module. In one embodiment, the current measurement system (10) and the voltage measurement system (11) are arranged on the vertical walls at the same height. In one embodiment, when the output bars (12) are L-shaped, the vertical section (121) is arranged in a coupled manner with the set of power inverter modules (9), receiving the connection with the inductors (14). In one embodiment, the user interface of the power source (1) is arranged on one of the vertical walls of the cabinet (15),being connected or communicated with the power supply control system (7) so that a user can program the operation mode and collect measurement data from the tests performed. In an alternative embodiment, the user interface is an external device, such as a computer, which is connected or communicated by cable or wirelessly with the power supply control system (7). In one embodiment, the beacon (13) is arranged on the top of the cabinet (15), on one of the vertical walls, being connected to the main power board (5) to indicate to a user the operation of the power supply (1) and that there is a risk of electrocution in the cables and connectors. ELECTRICAL TOPOLOGY Next,the electrical conversion topology that has been implemented in a particular configuration of the programmable power supply (1) in accordance with the present invention is presented. The proposed topology for the development of the programmable power supply (1) is shown in Figure 4. Since the objective of the source involves supplying an effective electric current of 2000 A, the area of ​​the set of power inverter modules (9) has been selected to carry out the development of the power supply (1). The set of power inverter modules (9) comprises a plurality of power inverter modules that operate in parallel to distribute the total output current (2000 A) equally between them. Each of these modules has a DC link formed by a set of capacitors and a pair of inductors (14) at its output terminals. In this way,Each inverter can be used to deliver a maximum controlled electric current of 198 A peak (140 A rms) in alternating current and 140 A in direct current, in each module. Each of these currents is directed to circulate through the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) arranged in its output terminals and achieve a temperature increase in them in a regulated manner. In one embodiment, a 220VAC to 24VDC conversion source with an isolation stage is used to supply electrical power to each of the DC links of the modules independently. This has been done because with the concentrated and common DC link for all modules, a high frequency circulating current between the modules became evident, which introduced additional unwanted and non-negligible losses in the conversion system. Using this solution, the high frequency circulating current has been eliminated and, consequently,the losses of the electrical source (1) have been reduced and the operating temperature of the electrical and electronic components of the power stage (capacitors, inductors and power modules) has been lowered. In addition, the development of the real-time control of the system has been simplified while maintaining its main premise of parallel control of inverter modules, this because it is not necessary to control the rectifier or a double control of circulating currents. The set of power inverter modules (9) can be simplified, as shown in figure 3, by taking into account the decoupling and isolation that the power supply introduces into the system. Each of the modules is connected to this arrangement through its inductors (14). In this case, ^^, ^^corresponds to the connector arrangement emulated by a short circuit. The inverter modules have semiconductors that act as switches to allow the circulation of electric current in the system. In addition, these can be adjusted to modulate a switched voltage at their output terminals, when operating together, in order to regulate the current flowing through them and, consequently, in the output arrangement corresponding to the conductors (2) and electrical connectors (3A, 3B, 3C, 3D). The modules are connected to their common connection point through an array of inductors capable of filtering harmonic components and enabling the implementation of the power supply control system. From this common connection point, the system current is supplied using a modular, multi-level, resilient, intelligent and programmable configuration.The electrical topology can be modeled by applying Kirchhoff's mesh law to the circuit in Figure 3 as indicated in (1.1) when considering n number of modules. In this expression, ^^. ^^^^ , ^^ ^^^^ , ^^ ^^^^ and ^^ ^^^^ They correspond to the voltage modulated by the inverter module, the electric current that flows through it in its output terminals and the equivalent resistance and inductance of the module's inductors. ^^ ^^ , ^^ ^^ and ^^ ^^ correspond to the output voltage, current, and equivalent resistance. Expressing the above relationship in matrix form, we obtain (1.2). This matrix equation defines the electrical dynamics of the topology in its inversion and output zone. For this reason, it is used for the development and implementation of the power supply control system. (1.2) The power supply and drive control system for the inverting configuration in Figure 3 relies on the use of a linear transformation to obtain the output current and the difference between the module currents from the current values ​​in each module. In this way, it is possible to control the output current and suppress any differences between the module currents independently, in order to regulate the current through the output array and mitigate any stress imbalance caused by the current in the modules. Inverter control model: The parallel connection of converters for high-current applications requires control techniques capable of operating the system as a modular structure where each unit contributes a fraction of the total current required by the system.Because of this, the nature of the power supply control system becomes multivariable, and its objective is to regulate the output current to the system's nominal value, together with the regulation of the circulating current between the modules, in order to meet the topology objectives by reducing stress and losses in the electrical and electronic elements of the conversion system. Topology modeling, based on the definition of equation (1.2), details the electrical dynamics of the conversion system. Initially, this relationship must be modified by considering the matrix in equation (1.3) as a new set of control variables to simplify its analysis. This results in the system of equations described in equation (1.4). The relationship that enables regulation of the output current and the circulating currents between the converter modules must be obtained by algebraic manipulation of equation (1.4). This is achieved by adding all the equations, as indicated in equation (1.5), and subtracting them, as shown in equation (3.6). Considering ^^^^1 = ^^^^2 = ... = ^^^^^^ = ^^^^^^^^ and ^^^^1 = ^^^^2 = ... = ^^^^^^ = ^^^^^^^^ for simplicity, equations (^^ − 1) are obtained from equation (1.6) that describe the difference between the currents {^^^^1, ^^^^2, ... , ^^^^^^} (circulating currents), while from equation (1.5) the total output current ^^^^^^^^^^^^^ = ^^^^^^^^ is obtained. With this, it is possible to construct a control space that presents ^^ equations fulfilling the regulation objectives of the power supply control system. Considering relations (1.5) and (1.6) it is possible to rewrite the system model as indicated in equation (1.7). where and ^^2are diagonal matrices defined as: The non-diagonal matrix ^^3, described in equation (1.8) relates the effect that the voltage of each inverter has on the dynamics of the currents. From equation (1.7) it is observed that the control variables of the system still depend on each other, due to this it is necessary to perform the transformation presented in equation (1.9). where, ^^4represents the inverse matrix of ^^3. Finally, replacing the new control signals in (1.7) gives the general control model of the system described in equation (1.10). Inverter Control Description: Figure 5 presents the parallel inverter control scheme where the control of the output current and the circulating currents presented in equation (1.10) are differentiated. The first control block in Figure 5 allows the regulation of the total supply current using proportional, integral and resonant controllers for the adjustment of an alternating or direct current as appropriate, this is done from the first equation in equation (1.10). The control of the circulating currents is carried out using the remaining equations of equation (1.10) and consists of (^^ − 1) controllers of identical structure and of proportional, integral and resonant character to regulate to a zero value the unwanted circulating current in the topology. The control of the system is carried out in the space constructed through equation (1.8).For this purpose, measurements are made in the original physical system, ^^. ^^^^ , are transformed through the transformation matrix ^^3 in order to obtain the expressions for the total current ^^^^^^^^^^^^and the errors ^^ in equation (1.10). By representing the relationships in equation (1.10) in the Laplace domain (frequency domain) we have the system plants described in equation (1.11). From equation (1.11) it can be seen that all plants in the system are defined in the same way, so the controllers to be used have equal gains for all cases. On the other hand, the necessary controller depends directly on the current reference to be manipulated, in that sense, if the reference current corresponds to a DC value, a PI controller is sufficient to ensure zero error in steady state, however, if the reference signal is a sinusoid, the use of PR controllers is necessary. In both cases, since a PR controller can be considered as a frequency-modulated PI, the controller gains can be calculated using the relations in equation (1.12). where ^^ ^^ and ^^ ^^^^correspond to the damping coefficient and natural frequency chosen for the control. These controllers are those presented in the respective blocks in Figure 5. The voltage references (^^ ^^ and ^^ ^^ ) obtained from them are transformed (inverse transformation using ^^4) to drive the system in its original space. The drive process is carried out using pulse width modulation (PWM), using the Interleaved methodology since this procedure allows a multilevel voltage to be formed at its output terminals and reduces the harmonic content of the system's output current in order to modulate a purely sinusoidal current profile.

Claims

CLAIMS 1. A programmable high current power source (1) for testing electrical connectors (3A, 3B, 3C, 3D) at high current by performing thermal aging and electrical wear tests due to overcurrent in an arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) with a nominal current between 10 A and 2000 A and a maximum output power of up to 5.5 kW, CHARACTERIZED in that it comprises: • a power supply socket (4) for the power source, which must be connected to a three-phase 380V source between phases, plus neutral and ground;• a main power board (5) that receives power from the power inlet (4) to feed a set of AC / DC power supplies (6), which deliver power to the components of the power supply (1), and a power board of a power supply control system (7), wherein said power supply control system (7) allows controlling the current in real time, programming the execution of tests and obtaining information on the tests performed; • an on / off command box (8) to energize / de-energize the power and control stages and the emergency stop; • a set of power inverter modules (9) that allows controlling a current in a range of 10 A to 2177 A peak effective, being limited to 2000 A for safety, in alternating current of 50 Hz or 60 Hz, and up to 1540 A in; direct current, providing sufficient current to perform the tests, which have a direct current link formed by a set of capacitors and at least one pair of inductors (14) in its output terminals, allowing the controlled electric current to be delivered in both alternating current and direct current, where each of the currents is directed to circulate in the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) arranged in its output terminals and achieve a regulated temperature increase; • a current measuring system (10) and a voltage measuring system (11) to control the output current of the electrical source (1);• the at least one pair of high current inductors (14) in each inverter module of the set of power inverter modules (9) with an approximate inductance of between 15 µH and 20 µH, being capable of filtering harmonic components and enabling the implementation of the power supply control system (7), each inductor (14) being connected to one of the output terminals of an inverter module at one of its ends and at the other end to a respective output bar (12), which allows the connection to be made with the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) to carry out the thermal performance tests; • a temperature measurement module for measuring temperatures in the power supply (1), which transforms the analog temperature measurement of the thermocouple into digital data to be transferred / transmitted;• a power supply user interface (1) that allows a user to communicate with the power supply control system (7) for programming; 2. The power supply (1) according to claim 1, characterized in that it further comprises a beacon (13) for indicating to a user the operation of the power supply (1) and that there is a risk of electrocution.

3. The power supply (1) according to claim 1 or 2, characterized in that the set of AC / DC power supplies (6) comprises: a power supply, independent for each inverter module of the set of power inverter modules (9), for converting 220VAC to 24VDC to energize the power stages of the inverter modules of the set of power inverter modules (9);a power supply, independent for each inverter module of the set of power inverter modules (9), for converting 220VAC to 12VDC to energize the electronic stage of the inverter modules of the set of power inverter modules (9); a power supply for converting 220VAC to 24VDC to energize the electronic stage of the current measurement system (10) and the voltage measurement system (11); and a power supply for converting 200VAC to 5VDC and 12VDC to energize the electronic stage of the power supply control system (7).

4. The power supply (1) according to claims 1 to 3, CHARACTERIZED in that the set of power inverter modules (9) comprises 11 modules; power inverters, each controlling 198 A peak in 50 Hz or 60 Hz alternating current, and 140 A in direct current.

5. The power supply (1) according to claim 4, characterized in that each inverter module comprises: an H-bridge card, which transports the power of the inverter module, allows the modulation of direct and alternating currents, and includes power transistors, heatsinks, fans and input / output power terminals of the module; 4 Gate-Driver cards to turn the transistors of the power module on and off, being mounted directly on the H-bridge card; a Power-Controller card that receives the power supply (12VDC), fiber optic pulses, conditions the drive signals and indicates the correct or incorrect operation of the module; a set of semiconductors that act as switches to allow the circulation of electric current. 6.The power supply (1) according to claim 5, CHARACTERIZED in that the semiconductor assembly comprises 8 semiconductors, so that the current of the power supply (1) can be distributed among several devices, in a coordinated manner, to allow a switching frequency of up to 5 kHz.

7. The power supply (1) according to claims 1 to 6, CHARACTERIZED in that the current measurement system (10) comprises a current sensor for each inverter module of the set of power inverter modules (9) and a plurality of current measurement cards with a total number of measurement channels that allow all the sensors to be connected.

8. The power supply (1) according to claim 7, characterized in that each current measurement card is supplied with 24 VDC and has 8 measurement channels, each with 4-pole connectors (+15 VDC / -15 VDC / GND / Measurement referred to GND), and two RJ-45 / UTP type outputs (4 measurements per output).

9. The power supply (1) according to claims 1 to 8, characterized in that the voltage measurement system (11) comprises a plurality of voltage measurement cards for measuring the potential difference in the inverter modules of the set of power inverter modules (9), the plurality of voltage measurement cards having a total number of measurement channels that allow all of the inverter modules of the set of power inverter modules (9) to be connected. 10.The power supply (1) according to claim 9, CHARACTERIZED in that the voltage measurement cards correspond to a card powered with 24VDC and has 4 voltage measurements, which are sent through a single RJ-45 / UTP type output channel, the maximum value that can be measured being ±120V instantaneous.

11. The power supply (1) according to claims 1 to 10, CHARACTERIZED in that the power supply control system (7) comprises: a Carrier card to connect all the components; a communications card with peripherals associated with the communication; at least 2 cards of. optical fibers, which send the pulses to activate / deactivate: the transistors of the inverter modules of the set of power inverter modules (9), the operation of the inverter modules and the command of the general contactor of the system; and an analog-digital conversion card, which receives the current and voltage measurements from the current measurement system (10) and the voltage measurement system (11) and conditions them for use in the power source control system (7) of the power source (1).

12. The power source (1) according to claims 1 to 10, CHARACTERIZED in that the high current inductors (14) comprise an air core that does not use ferromagnetic materials.

13. The power source (1) according to claim 12, CHARACTERIZED in that the high current inductors (14) comprise 360 ​​strands of electrically insulated wire, each with a section of 0.158 mm. 2, to withstand temperatures up to 125°C.

14. The power source (1) according to claims 1 to 13, CHARACTERIZED in that the output bars (12) correspond to a high purity copper profile with an ampacity reaching 2000 A rms and a cross-sectional area of ​​at least 1000 mm 2 .

15. The power source (1) according to claim 14, CHARACTERIZED in that the output bars (12) are 12 cm wide and 1 cm thick.

16. The power supply (1) according to claim 14 or 15, characterized in that the output bars (12) have an L shape, with a vertical section (121) to which the inductors (14) are connected and a horizontal section (122) to which the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) are connected.

17. The power supply (1) according to claim 14 to 16, characterized in that the connection of the output bars (12) and the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) is made by means of positive and negative cables on the output bars (12), which are connected, respectively, to an input conductor (21) and an output conductor (22), circulating the output current of the power supply (1). 18.The electrical source (1) according to claims 14 to 17, CHARACTERIZED in that the inductors (14) and the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D) are connected to the output bars (12) in perforations made with drill bits, preferably being 6 mm or 8 mm.

19. The electrical source (1) according to claims 14 to 17, CHARACTERIZED in that it comprises two output bars (12).

20. The electrical source (1) according to claims 1 to 17, CHARACTERIZED in that the temperature measuring module comprises a. set of independent temperature measuring modules each associated with a thermocouple (T), which transform the analog temperature measurement of the thermocouple (T) into digital data to be transferred / transmitted, comprising a module for measuring the ambient temperature, a module for measuring the temperature of a control conductor (23) and a module for measuring the temperature of each electrical connector (3A, 3B, 3C, 3D) in the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D).

21. The electrical source (1) according to claim 20, CHARACTERIZED in that the thermocouples (T) used are of the K type, with a maximum operating temperature of 500 ° C, a measurement accuracy of 1.5 ° C and a measurement resolution of ± 0.065 ° C. 22.

23. The power supply (1) according to claims 1 to 22, CHARACTERIZED in that it further comprises a cabinet (15), preferably in the form of a parallelepiped with its longer sides arranged vertically, defining an interior volume that allows components of the power supply (1) to be housed by arranging them vertically, comprising a base, in the form of a quadrilateral, from which two parallel, rectangular vertical walls project.

24. The power supply (1) according to claim 23, characterized in that the front access of the cabinet (15) comprises a door to prevent improper contact with the components of the power supply (1) and reduce the risk of accidents.

25. The power supply (1) according to claim 23 or 24, characterized in that the interior volume of the cabinet (15) comprises an internal shelf structure comprising a plurality of support trays for placing components of the power supply (1). 26.The power supply (1) according to claims 23 to 25, CHARACTERIZED in that: the power inlet (4) is arranged at the bottom of the left side of the cabinet (15), on the respective vertical wall; the main power supply board (5) is arranged at the bottom of the interior volume of the cabinet (15) to be connected to the power inlet and receive power to feed the AC / DC power supply assembly (6); the AC / DC power supply assembly (6) is arranged in the interior volume of the cabinet (15), above the main power supply board (5) for connection thereto, being connected, in turn, to the inverter modules of the assembly. of power inverter modules (9), to the current measurement system (10), to the voltage measurement system (11) and to the power supply board of the electrical source control system (7), to supply them with energy for their operation; the set of power inverter modules (9) is arranged in the upper part of the interior volume of the cabinet (15), being above the set of AC / DC power supplies (6); the current measurement system (10) is arranged on the right side of the cabinet (15), on the respective vertical wall, at a height that coincides with a part of the interior volume of the cabinet (15) where the set of power inverter modules (9) is located, such that said current measurement system (10) is connected to said set of power inverter modules (9) to carry out the current measurements of each inverter module;the voltage measuring system (11) is arranged on the left side of the cabinet (15), on the respective vertical wall, at a height that coincides with a part of the interior volume of the cabinet (15) where the set of power inverter modules (9) is located, such that said voltage measuring system (11) is connected to said set of power inverter modules (9) to carry out group voltage measurements of the set of power inverter modules (9); the on / off control box (8) is arranged on the right side of the cabinet (15), on the respective vertical wall, in a position below the current measuring system (10), being connected to the main power board (5), to carry out the energization / de-energization of the electrical source (1); the power supply control system (7) is arranged on the right side of the cabinet (15), on the respective vertical wall, in a position below the on / off command box (8), being connected to the main power board (5), to the AC / DC power supply assembly, to the power inverter module assembly (9), to the current measurement system (10), to the voltage measurement system (11) and to the arrangement of conductors (2) and electrical connectors (3A, 3B, 3C, 3D), to control the current in real time, to program the execution of tests and, to obtain the information of the tests carried out; and the output bars (12) are arranged on the back of the cabinet (15), in a position that coincides with the location of the power inverter module assembly (9), to connect with the inductors (14) of each inverter module. 27.The power supply (1) according to claim 26, characterized in that the current measuring system (10) and the voltage measuring system (11) are arranged on the vertical walls at the same height.

28. The power supply (1) according to claim 26 or 27, characterized in that the user interface is arranged on one of the vertical walls of the cabinet (15), being connected or communicated with the power supply control system (7) so that a user can program the operating mode and collect measurement data from the tests performed.

29. The power supply (1) according to claims 26 or 27, CHARACTERIZED in that the user interface is an external device, such as a computer, which is connected or communicated by cable or wirelessly with the power supply control system (7).

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