• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Rotary sensor for measuring alternating current and direct current simultaneously in a rotating machine, based on the magnetic coupling of an induced winding (3) and an inductor winding (4), through which the current to be measured installed in a rotor (2) circulates.) that rotates, where the induced winding is installed axially in the cylinder head (5) of a stator (1) in which a voltage proportional to the currents to be measured is induced. From the harmonic analysis of this voltage, the value of the measured current is obtained. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2798048A1
    申请号:ES202030993
    申请日:2020-10-01
    公开日:2020-12-04
    发明作者:Vicente Miguel Angel Pardo；Gaona Carlos Antonio Platero；Garcia Francisco Blazquez；Fernandez Jose Angel Sanchez
    申请人:Universidad Politecnica de Madrid；
    IPC主号:
    专利说明:

    [0004] OBJECT OF THE INVENTION
    [0006] The present invention consists of a sensor for the measurement of both alternating current (AC) and direct current (DC) in rotating machines. The sensor supplies the measurement of alternating current and / or direct current, from a rotating part, to a fixed part by means of an electromagnetic coupling. Therefore, the sensor consists of two parts, a rotating or rotor and a static or stator. Both parts have separate electrical windings. The inductor or excitation winding, located in the rotor, rotates at the same speed as the rotating machine, and the current of said machine to be measured is circulated through it. The stator winding is designed in such a way that it is traversed by the magnetic flux that is induced in the stator head. Therefore, the voltage in this stator winding is proportional to the variation in said flux of the stator head, which makes it possible to measure both the alternating current and the direct current flowing through the rotor.
    [0008] A clear application is in electrical power generation systems, in which synchronous generators are used. The excitation systems of these synchronous generators can be by means of static excitation (with brushes) or by means of brushless systems with alternating current exciter and rotating diodes, commonly known as the brushless type. In brushless type excitation systems, the excitation winding of the main synchronous machine is rotating and electric current flows through it. As there are no elements such as rings and brushes to access the winding, it is not possible to measure its current. The present invention has a clear application in this type of machine, since there are large centrifugal forces, electromagnetic fields, vibrations, possible presence of lubrication oil, etc. therefore electronic sensors with wireless communication are not suitable for these environments.
    [0009] The rotary current sensor of the invention for the measurement of alternating current (AC) and direct current (DC) of a rotating machine, supplies the measurement of the direct current that circulates through the excitation winding by means of an electromagnetic coupling without electronic components. making it suitable for the working conditions that exist in these machines. In the excitation windings, the fundamental component is direct current, but there is also an alternating component due to the ripple caused by the rotating diodes, therefore the invention also makes it possible to measure alternating current.
    [0011] BACKGROUND OF THE INVENTION
    [0013] The measurement of electrical parameters in rotating elements that rotate at a certain speed is complex due to the difficulty of access, since this implies the installation of slip rings and brushes. Both slip rings and brushes are high maintenance items, mainly cleaning and replacement respectively. Therefore, in many facilities they are not used. Another problem with these elements is the possibility of generating sparks, which means that, in many facilities with risk of explosion, such as refineries, they are strictly prohibited.
    [0015] Additionally, in rotating machines there are large centrifugal forces, vibrations, the possible presence of lubricating oil, large electromagnetic fields, among other factors that make the installation of wireless measurement systems not an adequate solution.
    [0017] In some electric generators without brushes (brushless type) electronic telemetry systems based on radio communications are installed. Due to high electromagnetic fields and high centrifugal forces, many of these systems frequently fail.
    [0019] There is no known sensor that supplies a measurement of alternating and / or direct current, from a rotating part, to a fixed part by means of an electromagnetic coupling, which solves the problem of this measurement, due to the high centrifugal force and electromagnetic fields. generated.
    [0021] In turn, there are also numerous inventions for the measurement of current, as for example described in document US9322850B2 Current measurement. In this document, a measuring equipment for high currents is claimed.
    [0023] The measurement of magnitudes in rotating equipment is also known, although in this case none of these equipment allows the measurement of current. Some of these inventions are collected in the following patents:
    [0025] US8536879B2 Rotating electric-field sensor. Describes equipment for measuring electric field from a rotating sensor.
    [0027] DE10240239A1 Hall sensor for measurement of rotation angle or angular velocity, e.g. for use in automotive applications, has a monolithic sensor body with multiple Hall voltage taps connected to an evaluation unit. It is a sensor to measure rotational angles from a high precision Hall sensor.
    [0029] EP0647854B1 Current sensor and motor rotation sensor using the current sensor. This invention measures the armature current of the motor and from the measurement of this current and with a sensor that measures impedance it calculates the motor speed.
    [0031] DESCRIPTION OF THE INVENTION
    [0033] The invention relates to the design of a rotary sensor for measuring alternating current and / or direct current. The operating principle of the sensor is based on a magnetic coupling between two coils or windings located in a stator and in a sensor rotor respectively, which are formed by laminated magnetic sheet.
    [0035] The rotor rotates at the same speed as the machine in which the measurement is to be carried out, and its winding is an inductive winding, through which the current to be measured is circulated, in such a way that it produces a magnetic flux, proportional to the current and the number of turns. This magnetic flux reaches the head of the stator, where it is divided by symmetry into two equal magnetic fluxes. These flows have been represented in the figures by lines that represent the path they travel.
    [0037] The stator winding is an induced winding, where a tension. It is located axially surrounding the head of the stator, so that it is crossed by half of the magnetic flux produced. The induced voltage in this winding is proportional to the variation of the magnetic flux.
    [0039] Direct current measurement.
    [0041] In the case of direct current measurement, it circulates through the inductor winding. In this case the magnetic field is unidirectional with a fixed amplitude if the value of the direct current to be measured does not vary. However, the flux changes direction every half turn of the rotor, as can be seen if we compare figure 1 and figure 2. Therefore, there is a flux variation every 180 ° of rotor turn. Due to this flux variation, a voltage of frequency equal to the turning frequency (fmec) of the machine is induced in the induced winding. The value of this voltage depends on the speed of rotation and on the direct current flowing through the inductor winding. Therefore, knowing the speed of rotation of the machine and the frequency component fmec of this voltage, the value of the direct current flowing through the induced winding can be obtained by means of known algorithms.
    [0043] Alternating current measurement (f1)
    [0045] In this case the magnetic flux is variable, with a frequency equal to that of the alternating current to be measured (f1). The sensor works like a transformer. Every half turn of the rotor, the alternating current flowing through the rotor winding produces a variable magnetic field in the stator of equal frequency (f1). When the sensor rotor begins a new half turn, the operation is similar, but the polarity of the induced voltage changes. Therefore, the frequency of the alternating current to be measured must be higher than the turning frequency.
    [0047] This operation is easily explained according to Leblanc's theorem, which says that a winding through which a single-phase alternating current circulates creates a pulsating magnetic field that is equivalent to two magnetic fields rotating in opposite directions.
    [0049] This, combined with the rotation of the rotor in a frequency direction (fmec), induces two frequencies in the induced winding (fmec f1) and (fmec - f1).
    [0050] If the frequency is measured in absolute value in the induced winding, these two frequency components correspond to (f1 fmec) and (f1 - fmec).
    [0052] The values of these components (f1 ± fmec) depend on the amplitude of the alternating current to be measured. Therefore, knowing the frequency components (f1 ± fmec) c of this voltage, the value of the alternating current flowing through the induced winding can be obtained by means of known algorithms.
    [0054] Measurement of direct current and alternating current (f1).
    [0056] In this case, three frequencies are mainly recorded, one corresponding to direct current (fmec) and two to the alternating component (fmec ± fl):
    [0057] -. Rotation frequency (fmec).
    [0059] The value of this component depends on the value of direct current.
    [0061] -. Frequency (fmec ± f1).
    [0063] The effective value of these components depends on the value of the alternating current to be measured.
    [0065] Consequently, an induced voltage signal is available in the induced winding of the stator and after analyzing its components, the alternating and direct currents can be measured by applying known algorithms.
    [0066] In one embodiment, it is envisaged that both the induced winding and the inductor are arranged in a part of the rotor and the stator respectively, as shown in Figures 1 to 3.
    [0068] In another embodiment of the invention it is envisaged that the induced winding that is located in the stator is installed divided into two parts at 180 ° and connected in series. As shown in figure 4. In this way the two parts of the winding see the same flow but with different directions. Therefore the same voltage is induced. By connecting both parts in series the two induced voltages are added. This configuration has the advantage that more turns can be installed, and the induced voltage is higher, with which the sensor has a greater ratio of induced volts per measured ampere. In this case, the inductor winding located on the rotor is also divided into two parts, connected in series, as shown in figure 4.
    [0070] BRIEF DESCRIPTION OF THE FIGURES
    [0072] Next, a series of drawings are very briefly described that help to better understand the invention and that expressly relate to an embodiment of said invention that is presented as a non-limiting example thereof.
    [0074] Figure 1 represents a schematic section of a possible embodiment of the sensor where the stator (1), the rotor (2) and the induced (3) and inductor (4) windings are observed. In this preferred embodiment, both windings (3 and 4) are concentrated in a single area of equipment to be measured. The cylinder head (5) of the stator (1) is surrounded by the induced winding (3), so this is traversed by the magnetic flux that circulates through the cylinder head.
    [0076] Figure 2 represents the same embodiment of figure 1, where the magnetic flux (6) circulating through the cylinder head (5) has been represented by flux lines. It can be seen that the flux created by the inductor winding (4) is divided by symmetry into two equal fluxes upon reaching the stator. In this figure, the rotor has been represented in a position such that the inductor winding (4) is at the top of the rotor, above the induced winding (3). For a given current, the flow through the cylinder head goes from top to bottom through the induced winding (3).
    [0078] Figure 3 is similar to figure 2, however the inductor winding (4) has been represented in the lower part. In this figure the direction of the magnetic flux is the opposite, so for the same current represented in figure 2 the flux through the induced winding (3) goes from bottom to top
    [0080] Figure 4 represents a schematic section of another possible embodiment of the sensor where the stator (1), the rotor (2) and the induced (3) and inductor (4) windings are observed. In this embodiment, both windings are located in two sensor zones, and each part of the windings are connected in series. So that the inductor winding (4) produces a greater magnetomotive force as it has more turns and a greater electromotive force is induced in the induced winding (3).
    [0082] PREFERRED EMBODIMENTS OF THE INVENTION
    [0084] Sensor with concentrated windings
    [0086] In a first embodiment, both the inductor winding (3) and the induced winding (4) are installed in a single point of the sensor, as shown in Figures 1 to 3.
    [0088] Sensor with windings located in two parts of the machine
    [0090] In a second embodiment, both the inductor winding (3) and the induced winding (4) are installed at two points of the sensor, as shown in figure 4.
    [0092] The sensor object of the present invention is coupled to the axis of the machine where the current is to be measured. It consists of a stator (1) and a rotor (2), which rotates at the same speed as the machine shaft, as it is coupled to its shaft. The rotor can be constituted by the rotor itself of the machine in which it is desired to measure the current, and the stator can be arranged outside said machine.
    [0093] The stator (1) comprises a fixed magnetic core that is composed of laminated magnetic plates and has at least one induced winding (3), axially wound, housed in such a way that it concatenates the magnetic flux (6) that circulates through the cylinder head (5 ) of the stator (1). This winding has a certain number of turns, and is represented in Figures 1 to 3. The rotor (2) comprises a rotating magnetic core, which is also composed of laminated magnetic sheets and has at least one inductive winding (4) installed, axially wound, as shown in Figures 1 to 3, through which the current to be measured is circulated. This current, which circulates through the inductor winding (4), causes a radial flow, which once it reaches the head (5) of the stator is divided into two magnetic flows (6). The arrangement of the induced winding (3) causes it to concatenate half of the flux produced, and therefore a voltage proportional to the variation of the magnetic flux is induced.
    [0094] DC current measurement
    [0096] In the case of direct current measurement, this circulates through the inductor winding (4). In this case the magnetic field (6) is unidirectional with a fixed amplitude if the value of the direct current to be measured does not vary. However, the flux changes direction every half turn of the rotor, as can be seen if we compare figure 2 and figure 3. Therefore, there is a flux variation every 180 ° rotation of the rotor (2). Due to this flux variation, a voltage with a frequency equal to the turning frequency (fmec) of the machine is induced in the induced winding (3). The value of this voltage depends on the rotation speed and the direct current flowing through the inductor winding (4). Therefore, knowing the frequency component fmec of this voltage (rotational speed), the value of the direct current flowing through (3) can be obtained by means of known algorithms.
    [0098] Alternating current measurement (f1)
    [0100] In this case the magnetic flux (6) is variable, with a frequency equal to that of the alternating current to be measured (f1). The sensor works like a transformer. Every half turn of the rotor, the alternating current flowing through (4) produces a variable magnetic field in (3) of equal frequency (f1). When the sensor rotor (2) begins a new half turn, the operation is similar, but the polarity of the induced voltage changes. Therefore, the frequency of the alternating current to be measured must be higher than the turning frequency.
    [0102] This operation is easily explained according to Leblanc's theorem, which says that a winding through which a single-phase alternating current circulates creates a pulsating magnetic field that is equivalent to two magnetic fields rotating in opposite directions.
    [0104] This, combined with the rotation of the rotor (2) in a frequency direction (fmec), induces in the winding (3) two frequencies (fmec f1) and (fmec - f1).
    [0106] If the frequency is measured in absolute value in the winding (3), these two frequency components correspond to (f1 fmec) and (f1 - fmec).
    [0107] The values of these components (f-i ± fmec) depend on the amplitude of the alternating current to be measured. Therefore, knowing the frequency components (^ ± fmec) c of this voltage, the value of the alternating current flowing through (3) can be obtained by means of known algorithms.
    [0109] Measurement of direct current and alternating current (f ^.
    [0111] In this case, three frequencies are mainly recorded, one corresponding to direct current (fmec) and two to the alternating component (fmec ± fl):
    [0112] -. Rotation frequency (fmec).
    [0114] The value of this component depends on the value of direct current.
    [0116] -. Frequency (fmec ± f1).
    [0118] The effective value of these components depends on the value of the alternating current to be measured.
    [0120] Consequently, an induced voltage signal is available in the stator and after analyzing its components, the alternating and direct currents can be measured by applying known algorithms.
    权利要求:
    Claims (3)
    [1]
    1. Rotating sensor for measuring direct and / or alternating current in a rotating machine, comprising:
    - a rotor (2), which rotates at the known rotational speed of the machine in which the current is to be measured;
    - an inductor winding (4), located in the rotor, through which the current to be measured flows;
    - a stator (1), equipped with a cylinder head (5) in which a magnetic flux (6) proportional to the current flowing through the inductor winding (4) to be measured is induced.
    characterized in that it comprises an induced winding (3), wound in an axial direction in the stator to induce a voltage proportional to the variation of said magnetic flux (6), induced in the cylinder head (5), and proportional to the current flowing through the inductor winding (4); allowing the measurement of direct and alternating current through analysis of the harmonics of the induced voltage.
    [2]
    2. Sensor according to claim 1, characterized in that the inductor winding (4) is located in a part of the rotor.
    [3]
    3. Sensor according to claim 1, characterized in that the armature winding (3) is divided into two parts located in the stator and connected in series; and the inductor winding (4) is also divided into two parts located on the rotor and connected in series.
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    同族专利:
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    ES2798048B2|2021-08-05|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US6373155B1|1999-09-06|2002-04-16|Suzuki Motor Corporation|Propulsion unit of vehicle|
    US7075196B1|2002-08-13|2006-07-11|Quicksilver Controls, Inc.|Integrated resolver for high pole count motors|
    EP3225447A1|2016-03-31|2017-10-04|Kabushiki Kaisha Toyota Jidoshokki|Structure for mounting rotation sensor to electric motor in hybrid power unit|
    法律状态:
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    优先权:
    申请号 | 申请日 | 专利标题
    ES202030993A|ES2798048B2|2020-10-01|2020-10-01|ROTARY SENSOR FOR MEASURING ALTERNATING CURRENT AND / OR DIRECT CURRENT IN ROTATING MACHINES|ES202030993A| ES2798048B2|2020-10-01|2020-10-01|ROTARY SENSOR FOR MEASURING ALTERNATING CURRENT AND / OR DIRECT CURRENT IN ROTATING MACHINES|
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