ELECTRIC MOTOR WITH ROTATION ENCODER
By integrating rotation coder sensors into the electronic control card of electric wheel drive engines, the system becomes more compact, easier to repair, and achieves precise engine rotation control, addressing the challenges of existing technologies.
Patent Information
- Application Number
- FR2022001283
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-02-14
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2042-02-14
AI Technical Summary
Existing electric wheel drive engines, particularly in robotic handling devices, face challenges in compactness, ease of operation, and repairability due to the separate installation of rotation coder sensors and control electronics.
Integration of rotation coder sensors into the electronic control card mounted on the engine, which includes a power supply and steering device for the stator windings, along with an angular encoding element, to create a compact and modular engine control block.
This solution enables a more compact and easily implantable engine control system, simplifies repair by allowing the card to be disassembled, and improves precision in engine rotation control through direct integration of sensors and control electronics.
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Abstract
Description
Title of the invention: ELECTRIC MOTOR WITH ROTATION ENCODER Technical field
[0001] The present disclosure relates to the field of controlling electric motors, in particular electric motors for driving wheels such as wheels of robotic handling devices, and relates to an electric motor provided with a rotation encoder. Prior art
[0002] Electric wheel drive motors can be motors controlled by motor control electronics powered by a direct current source such as a battery for example. For the purpose of precise control of the rotation of the motor, it is useful to know the position and rotation speed of the motor rotor. Generally, a rotation encoder comprises a rotating part mounted on the motor shaft and a sensor to return this information to the motor control.
[0003] The encoder sensor is generally fixed to the motor and connected by wire to the motor control electronics located in the motor. Summary
[0004] In particular for robotic handling devices, it is desirable to make the motor and its control electronics more compact, to make the operation of the assembly more reliable and to simplify the repairability of this assembly. The present disclosure proposes to do this by integrating sensors of a motor rotation encoder into said electronics, the latter being attached to the motor.
[0005] Thus, the present disclosure proposes an electric motor comprising a motor shaft carrying a rotor, a device for supplying and controlling the phases of windings of a stator of said motor on an electronic card fixed to the motor and one or more angular encoders, for which said angular encoders comprise sensors positioned on said electronic card and an angular encoding element arranged opposite the sensors on the motor shaft, and for which said electronic card comprises power electronics for controlling said windings and a unit for calculating and controlling the phase of said windings.
[0006] This makes it possible to produce a compact and easily implantable block while allowing the card to be dismantled for possible repair.
[0007] The features set out in the following paragraphs may, optionally, be implemented, independently of one another or in combination with one another:
[0008] According to a first embodiment, the electronic card is crossed by the motor shaft. According to an alternative embodiment, the electronic card is opposite one end of the shaft.
[0009] Advantageously, the electronic card is positioned in a removable and replaceable flange, fixed on a face of a motor casing called the rear face, crossed by said motor shaft, said flange comprising a bottom provided with a hole crossed by said motor shaft and a border surrounding the perimeter of the electronic card, said sensors being opposite said angular encoding element carried by said motor shaft.
[0010] The angular encoding element is advantageously a multipolar magnet and the sensors are magnetic field sensors, which prevents dust or dirt from disturbing the measurements.
[0011] A rear cover can be fixed to the flange, the rear cover and the flange forming a housing closing a space for receiving said electronic card. Thus the card secured to the motor as well as the motor shaft are protected.
[0012] The flange may comprise a non-magnetic cylindrical wall with a common axis with the motor shaft arranged between the multipolar magnet and the sensor(s) so as to separate and seal the housing of said electronic card.
[0013] The motor shaft may be extended by a segment passing through an opening in the rear cover to provide support for at least one additional piece of equipment.
[0014] Said additional equipment may be an electromechanical brake comprising a disc and one or more calipers connected and controlled by the electronic card, said calipers being mounted on the rear cover of the block, said disc being mounted on said through segment.
[0015] The present disclosure further relates to an electronic card for an electric motor as described above which comprises a hole for passage of said motor shaft and one or more angular encoder sensors arranged at the periphery of said hole.
[0016] The electronic card may include power supply connection pins for the stator windings adapted to be connected to a connector grouping the stator power supply wires at the flange. Thus, the card is easily connected to the motor power supply cables.
[0017] The electronic card may include a communication component with a management system of a handling device of which said motor drives one or more wheels.
[0018] The card can be programmed to provide an external computer with speed information, calculations of motor position increments and motor rotation direction through said communication component.
[0019] The present disclosure also relates to a rolling machine comprising at least one motor and an electronic card according to any one of the claims as described previously.
[0020] The present disclosure finally relates to a method of assembling and calibrating a motor equipped with a card as described which comprises after assembly of the motor and assembly of the electronic card:
[0021] - a fixing of the angular encoding element on the motor axis, a fixing of the board equipped with sensors in its final mechanical position on the motor, the relative angular position of the magnet with respect to the board sensors being arbitrary and unknown,
[0022] - forced rotation of the rotor by applying a rotating magnetic field by controlling the motor stator with the application of a defined three-phase voltage producing a defined rotating field for one complete revolution,
[0023] - a measurement by means of sensors of the states of the magnetic field caused by the magnet during the forced rotation of the axis, and a determination by the calculation unit of the angular deviation between said states of the magnetic field measured by the sensors and the position imposed during the rotation of the motor by the field applied to the stator;
[0024] the differences between said measured states and said imposed position being stored in permanent memory in the card and constituting the calibration data for a card encoder motor assembly. Brief description of the drawings
[0025] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:
[0026] [Fig-1] shows a schematic side sectional view of one embodiment;
[0027] [Fig.2] shows a schematic side view in section according to one embodiment complementary.
[0028] [Fig.3] shows a perspective view of a motor equipped with an electronic card in a flange;
[0029] [Fig.4] shows an example of a ring magnet;
[0030] [Fig.5] shows a variant device of the present disclosure. Description of the embodiments
[0031] Reference is now made to [Fig. 1] which schematically represents in longitudinal section an electric motor 1 comprising a rotor 2 on a motor shaft 5 and a stator whose windings 20 are supplied by a control device with electronic switches. Such a motor of the brushless direct current motor type known by the abbreviation BLDC motor for brushless direct current motor in English is controlled by a converter and assimilated to a direct current motor.
[0032] The motor may be, in a known manner, a three-phase brushless motor whose phases are supplied by a power switching system with three MOSFET or IGBT power half-bridges controlled independently by a programmable computer of a device for supplying and controlling the phases of the motor windings in a motor control electronics.
[0033] For the purpose of precise control of the rotation of the motor, it is useful to know the position and the rotational speed of the rotor of the motor. Generally, a rotation encoder is mounted on the motor shaft to return this information to the motor control. In the example of the present disclosure, in particular in Figures 1, 2 and 5, the encoder is produced by integrating magnetic sensors 7 directly on an electronic motor control card 3 opposite an angular coding element 6, constituted here by an annular multipolar magnet, for example a magnet with twelve pairs of poles 6a, 6b as shown in [Fig. 4], mounted on the motor shaft 5 opposite the sensors, which makes it possible to obtain information on the speed and angular position of the motor directly by the electronics of the control and piloting device.
[0034] According to figures 1 and 2, the card 3 has an opening to be crossed by the shaft 5, the sensors being on the periphery of the opening, and according to [Fig.5] the card 3' is located opposite one end of the shaft, the sensors 7' being located on a so-called lower face of the card opposite the angular encoding element 6.
[0035] The electronic card 3 is, according to the example, mounted in a flange 4 perpendicular to an axis of the motor shaft. The flange is arranged on a face 21a of a motor casing 21 at an axial end, called the rear end, of the motor and provides an interface between the rear end of the motor and the electronic card. The flange comprises a bottom wall 41 fixed to a rear wall 21a of the motor and an edge 44, the flange forming a receptacle in which the electronic card 3 is securely fixed and positioned relative to the motor shaft.
[0036] The sensors 7 of the angular encoders are here magnetic field sensors such as Hall effect sensors for example and are positioned on said electronic card opposite the annular multipolar magnet 6 itself positioned on the motor shaft 5 passing through said card.
[0037] The sensors are of the magnetic field sensor type and may in particular be Hall effect sensors. Three sensors distributed at 120° around the multipolar magnet on the motor shaft as shown in [Fig.3] allow sufficient precision for operation of the motor as a means of driving a wheel of a handling device.
[0038] A solution with optical encoders comprising optical sensors and an optical encoder wheel can also be envisaged within the framework of the present disclosure or a solution with a toothed encoder wheel and magnetic sensors.
[0039] The device of the present disclosure has the advantage of bringing together all the electronic functions, control and sensors of the encoder, in a single mechanical assembly forming a motor control unit. The elements of this control unit can be assembled separately from the motor, the motor control unit becoming a modular functional unit which will be directly placed on the motor at the end of the production line for example. Several versions of motor control units can be proposed for the same motor, and the easy replacement of said control unit facilitates maintenance of the device.
[0040] According to the example of [Fig.l], the electrical phase cables of the motor are connected via a connector 43 mounted on the flange and receiving contact pins 32 coming from the electronic card to facilitate the assembly and replacement of the motor control unit or the electronic card. These cables can be connected directly to the electronic card 3 as shown in [Fig.2].
[0041] [Fig.2] represents an embodiment for which a rear cover 8 is fixed to the flange, this rear cover and the flange forming a housing closing a space for receiving said electronic card which protects it from external attacks.
[0042] A non-magnetic cylindrical wall 9 with a common axis with the motor shaft 5 may also be provided, arranged between the multipolar magnet and the sensor(s), which makes it possible to seal the housing of said electronic card and to protect it even better.
[0043] Still according to the variant of [Fig.2], the motor shaft can be extended by a segment 5a passing through an opening in the rear cover 8 to provide a support for at least one additional piece of equipment which can be an electromechanical brake comprising a disc 11 and one or more calipers 10 connected and controlled by the electronic card.
[0044] In this example, the calipers are mounted on the rear cover 8 of the control unit and the disc is mounted on said through segment 5a.
[0045] [Fig. 3] shows the mounting of the electronic card 3 in the flange 4 at the rear of the motor, this card being for example fixed on spacers 43 of the flange by screws 38.
[0046] The card has a hole 31 to allow the multipolar magnet 6 to pass through and the sensors 7a, 7b, 7c are arranged around said magnet at the periphery of the hole.
[0047] The electronic card further comprises power electronics 33 and a calculation unit 34 such as a microprocessor or a microcontroller, associated with a permanent memory 35 for example of the EEPROM type to be able to be updated, comprising the motor control program and the calibration data and a random access memory 36, for controlling the phases of the motor. The card even comprises actually a communication component 37, for example a field bus management component of the CAN or Ethernet type, or a radio link such as Wifi, Bluetooth, Zigbee, or even 5G connected to the computing unit and to an antenna not shown or a wired connection component connecting the electronic card with a controller calculator on rolling stock such as a handling device comprising one or more motors of the present disclosure to drive wheels of said equipment to allow the electronic card to communicate with a management system of said remote or on-board rolling stock.
[0048] According to an important aspect, the device as shown does not include mechanical adjustment of angular position between the multipolar magnet and the motor windings. A self-calibration procedure is carried out once the electronic card is assembled on the motor to know the angular position of the rotor and control the phases of the stator relative to the rotor, which is important for maximizing the starting torque of the motor.
[0049] The self-calibration procedure is carried out either at the end of the production line or when the product is first put into service, following the pairing of the electronic sensor assembly and the motor supporting on its axis the means providing the position information, multipolar magnet, encoder wheel or other.
[0050] For this procedure:
[0051] after assembly of the motor and assembly of the electronic card:
[0052] - the angular encoding element 6 is fixed on the motor axis, for example by gluing, and the card 3 is arranged in its final mechanical position on the motor. After these operations, the relative angular position of the encoding element, for example a multipolar magnet, with respect to the sensors 7 of the card is arbitrary and unknown.
[0053] Then the rotor 2 is set into rotation by applying a magnetic field by controlling the stator 20 of the motor with the application of a defined three-phase voltage producing a defined rotating field and the position of the motor is thus imposed for 1 complete revolution;
[0054] During the forced rotation of the axis, the sensors 7 measure the states of the magnetic field caused by the magnet, and the calculation unit 34 determines the angular difference between said states measured by the sensors and the position imposed during the rotation of the motor by the field applied to the stator;
[0055] The differences between said measured states and said imposed position are stored in permanent memory (35) in the card and constitute the calibration data for a card encoder motor assembly.
[0056] The procedure is fully automated and makes it possible to overcome variations linked to mechanical assembly by determining the parameters allowing the shaping or standardization of the signal received by the sensor(s).
[0057] The procedure then allows the information from the sensor to be matched with the position of the motor rotor, allowing the information from this sensor to be used to generate the rotating magnetic field used for motor control.
[0058] According to the example of [Fig.3], the encoder device comprises three logic sensors 7a, 7b, 7c offset by 120° facing the annular multipolar magnet with 12 pairs of poles, which gives six recombinant states, i.e. a relative position at 72° for basic control of the motor. The number of pairs of poles can, however, be greater for greater precision. To obtain greater precision, two analog sensors 71a, 71b arranged at 90° in sine / cosine can be added facing the multipolar magnet or the number of logic sensors can be increased. Positioning the sensors directly on the electronic card avoids having electrical connection cables between them and said card and makes the assembly more robust against vibrations in particular.
[0059] For applications requiring significant operational safety, it is also possible to use additional side-by-side redundancy sensors, sensors providing redundant measurements, or a safety encoder with a safety controller.
[0060] In a case where a zero point of rotation of the motor is desirable a sensor, for example an additional magnetic sensor can be arranged opposite a pin or a groove on the metal shaft.
[0061] The invention is not limited to the examples shown and in particular the electronic card can be subdivided into modules for better repairability.
Claims
Claims
1. Electric motor (1) comprising a motor shaft (5) carrying a rotor (2), a device for supplying and controlling the phases of windings (20) of a stator of said motor on an electronic card (3, 3') fixed to the motor and one or more angular encoders comprising sensors (7, 7') positioned on said electronic card and an angular encoding element (6) arranged opposite the sensors on the motor shaft, characterized in that said electronic card comprises power electronics (33) for controlling said windings and a unit (34) for calculating and controlling the phase of said windings.
2. Electric motor according to claim 1 for which the electronic card (3) is crossed by the motor shaft.
3. Electric motor according to claim 1 or 2 for which the electronic card is positioned in a removable and replaceable flange (4), fixed on a face (21a) of a motor casing (21) called the rear face, crossed by said motor shaft (5), said flange comprising a bottom (41) provided with a hole crossed by said motor shaft (5) and a border (42) surrounding the perimeter of the electronic card, said sensors being opposite said angular encoding element (6) carried by said motor shaft (5).
4. Electric motor according to claim 1, 2 or 3 wherein the angular encoding element (6) is a multi-pole magnet and the sensors (7, 7') are magnetic field sensors.
5. Electric motor according to any one of the preceding claims comprising a rear cover (8) fixed to the flange, the rear cover and the flange forming a housing (4, 8) closing a space for receiving said electronic card.
6. Electric motor according to any one of the preceding claims, for which the flange comprises a non-magnetic cylindrical wall (9) with a common axis with the motor shaft (5) arranged between the multipolar magnet and the sensor(s) so as to separate and seal the housing of said electronic card.
7. Electric motor according to any one of the preceding claims, for which the motor shaft (5) is extended by a segment (5a) passing through an opening in the rear cover (8) to provide support for at least one additional piece of equipment.
8. An electric motor according to claim 7 wherein said equipment complementary is an electromechanical brake (10, 11) comprising a disc (11) and one or more calipers (10) connected (12) and controlled by the electronic card, said calipers being mounted on the rear cover (8) of the block, said disc being mounted on said through segment (5a).
9. Electronic card for an electric motor according to any one of the preceding claims, characterized in that it comprises a hole for the passage of said motor shaft and one or more angular encoder sensors arranged at the periphery of said hole.
10. Electronic card according to claim 9 comprising pins (32) for connecting the stator windings to a power supply adapted to be connected to a connector (43) grouping the stator power supply wires at the flange.
11. Electronic card according to claim 9 or 10 comprising a communication component (37) with a management system of a handling device of which said motor drives one or more wheels.
12. Electronic card according to claim 11 for which the card is programmed to provide an external computer with information on speed, calculations of engine position increments and direction of engine rotation through said communication component.
13. Rolling machine comprising at least one electric motor according to any one of claims 1 to 8 and an electronic card according to any one of claims 9 to 12.
14. Method for assembling and calibrating an electric motor according to any one of claims 1 to 8 equipped with a card according to any one of claims 9 to 12, characterized in that it comprises, after assembly of the motor and assembly of the electronic card: a. - fixing the angular encoding element (6) on the motor shaft (5), fixing the card (3) equipped with the sensors (7) in its final mechanical position on the motor, the relative angular position of the magnet (6) with respect to the sensors (7) of the card being arbitrary and unknown, b. forced rotation of the rotor (2) by applying a rotating magnetic field by controlling the stator (20) of the motor with the application of a defined three-phase voltage producing a defined rotating field for a complete revolution, c. measurement by means of the sensors (7) of the states of the ma- magnetic field caused by the magnet during the forced rotation of the axis, and a determination by the calculation unit (34) of the angular deviation between said states of the magnetic field measured by the sensors and the position imposed during the rotation of the motor by the field applied to the stator; The deviations between said measured states and said imposed position are stored in permanent memory in the card and constitute the calibration data for a card encoder motor assembly.