TEST RACK FOR HIGH-SPEED BRUSHLESS ELECTRIC MOTORS

Abstract

This utility model relates to measurement technology and test equipment, specifically to test rigs for high-speed brushless electric motors. The rig comprises a test rig controller connected to a personal computer, a speed sensor, a mechanical assembly for mounting the motor, and a system for measuring electrical parameters. The device also includes a battery, a shunt, a speed controller, and a controlled current source. The load unit is a disk made of conductive material attached to the additional motor shaft, and a single-winding transformer connected to the controlled current source and mounted so as to allow contactless interaction with the disk.The torque measurement system consists of a lever attached to the motor, a stop, and a strain gauge. The lever is mounted so that it can interact with the strain gauge via the stop, and the strain gauge output is connected to the test rig controller. The motor is powered from a battery via a shunt and a speed controller, and the electrical parameter measurement system includes a voltage sensor and is connected to the shunt. The technical result is increased accuracy and stability in measuring the mechanical characteristics of high-speed electric motors under conditions simulating their actual operation. This is achieved through smooth load regulation using a contactless electromagnetic inductor without mechanical wear of the components, direct torque measurement using a balance lever with a strain gauge, and autonomous motor power from the battery, eliminating line interference. 1 fig.

Description

[0001] The utility model relates to electrical measuring equipment, in particular to means for diagnosing and testing electrical machines, namely high-speed brushless DC electric motors.

[0002] An analogue of the proposed device is a test bench for traction electric motors (RU No. 2750224 C1 dated 06 / 24 / 2021), containing a control panel, a speed sensor, the input of which is connected to the electric motor, power equipment connected to the electric motor and to the network, automatic control equipment, as well as a protection unit for the measured parameters.

[0003] The disadvantage of this device is its limited functionality, namely: the complexity of the design, aimed at heavy traction machines, the lack of a specialized loading system for high-speed motors with a low moment of inertia, as well as the lack of the ability to power from low-voltage DC sources (batteries), which is critical for diagnosing motors of mobile electric vehicles (UAVs, electric scooters).

[0004] The prototype of the device is a test bench for DC and AC electric motors (RU No. 2670715 C9 dated 10.24.2018), containing a control panel connected to a controller, a personal computer, a generator mechanically connected to the shaft of the electric motor being tested to create a load, a tachometer, and a system for measuring electrical parameters (ammeters, voltmeters) connected to a personal computer.

[0005] The disadvantage of this device is its limited functionality, namely: the use of a generator as a load element, which imposes restrictions on the maximum speed and accuracy of braking torque generation for high-speed BLDC motors due to inertia and mechanical friction; the lack of a stator torque measurement system (the "reactive" method) using strain gauges; power supply from a stationary network, which does not allow simulating operation from a limited energy source (battery).

[0006] The objective of the utility model is to develop a test rig for high-speed brushless electric motors, which eliminates the shortcomings of the analogue and prototype.

[0007] The technical result is to expand the functional capabilities of the prototype by providing testing of high-speed motors using contactless electromagnetic braking, increasing the accuracy of measuring mechanical characteristics (torque) and simulating real operating conditions with battery power.

[0008] The technical result is achieved in that the test bench for high-speed brushless electric motors includes a test bench controller, a personal computer (PC), a speed sensor, a voltage sensor, a motor under test, a shaft and a frame.

[0009] The stand includes a storage battery, a shunt, a speed controller, a copper disk, a single-winding transformer, a controlled current source, a lever, a load cell stop, a load cell, and a thrust bearing.

[0010] The test bench controller is connected via two-way communication to the PC and the controlled current source. The test bench controller outputs are connected to the speed controller. The test bench controller inputs are connected to the outputs of the voltage sensor, shunt, speed sensor, and strain gauge.

[0011] The power circuit consists of a battery connected via a shunt to the speed controller input, the output of which is connected to the motor. The voltage sensor is connected in parallel to the battery output.

[0012] The mechanical part of the stand is mounted on a frame and includes a motor whose shaft is rigidly connected to a copper disk. The shaft rests on a thrust bearing. A lever is attached to the motor stator or its mount, interacting with the load cell through the load cell stop.

[0013] The load unit is made in the form of a single-winding transformer connected to a controlled current source and installed with an air gap relative to a copper disk to create a braking torque using eddy currents.

[0014] The essence of the utility model is explained by a drawing, where the figure shows a structural diagram of a test bench for high-speed brushless electric motors.

[0015] The stand contains:

[0016] Test Rig Controller (1): It is a programmable logic controller (PLC) or a specialized microprocessor module that performs the functions of controlling the entire testing process, collecting data, implementing logical protection, monitoring modes and communicating with a personal computer (17).

[0017] Speed ​​controller (2): Designed as a high-precision frequency converter (for AC motors) or a thyristor / transistor converter (for DC motors), which provides smooth and precise control of the rotation speed (RPM) of the tested motor (5) by regulating the supplied voltage and / or frequency.

[0018] (not shown in the diagram, reserved) (3): Reserved element for possible addition of new functionality or additional measurement channel in the future.

[0019] AKB (Battery) (4): A set of lead-acid or lithium-ion cells that serves as a source of direct current to power the engine under test (5) when operating in generator mode or to provide power to the control and power circuits of the stand.

[0020] Motor (tested) (5): Representing a traction electric motor (TEM) of a locomotive, electric train or other vehicle, which is installed on a test bench to conduct various types of tests, such as load, thermal, switching and speed tests.

[0021] Shaft (6): Made in the form of a connecting element (coupling), which provides a mechanical connection between the shaft of the tested motor (5) and the rotor of the loading device - the copper disk (7) of the electromagnetic brake.

[0022] Copper disk (7): This is the rotor element of the eddy current brake (dynamometer), rigidly attached to the shaft (6). Rotation of this disk in the magnetic field generated by the transformer (8) induces eddy currents, which create a braking torque (mechanical load).

[0023] Single-winding transformer (electromagnet) (8): Designed as the stator portion of an eddy current brake, it creates an adjustable magnetic field around a copper disk (7). It is powered by a controlled current source (13) and is responsible for the intensity of the braking torque (load).

[0024] Lever (9): Designed as a torsion lever (reactive torque), rigidly attached to the electromagnet housing (8). It serves to convert the reactive braking torque acting on the brake stator (8) into a force that can be measured by the strain gauge (11).

[0025] Load Cell Stop (10): Which is a rigid mechanical support or bracket against which the lever (9) is applied or pushed, ensuring the transmission of the measured force to the load cell (11).

[0026] Load sensor (11): It is a high-precision electronic force sensor installed at the end of the lever (9) at the stop (10), which measures the applied force proportional to the mechanical torque of the motor under test (5).

[0027] Thrust bearing (12): Made in the form of a rolling or sliding bearing unit, providing reliable and accurate fixation of the shaft (6) and free rotation of the dynamometer rotor (7), minimizing friction losses.

[0028] Controlled Current Source (13): A precision DC current source that regulates the amount of current supplied to the electromagnet winding (8), providing precise and smooth control over the braking torque (load) on the motor shaft.

[0029] Speed ​​sensor (14): Made in the form of an incremental or absolute encoder (or tachometer), fixed on the shaft (6), which generates electrical pulses, the frequency of which is directly proportional to the rotation frequency of the shaft of the engine being tested (5).

[0030] Voltage sensor (15): Which is a high-voltage voltage divider or voltage measuring transducer connected to the terminals of the motor under test (5) to accurately measure its operating or supply voltage.

[0031] Shunt (16): In the form of a very low resistance calibration resistor installed in series with the motor power supply circuit (5), which creates a small but accurate voltage drop proportional to the current, allowing the motor operating current to be measured.

[0032] PC (Personal Computer) (17): It is a workstation with specialized software installed, used for visualization, archiving, analysis of test results, report generation and remote control of the controller (1). All elements of the mechanical part are mounted on the frame.

[0033] The device operates as follows.

[0034] The motor under test (5) is mounted on the stand, its shaft is connected to the shaft (6), on which a copper disk (7) is fixed.

[0035] When starting the test process, the operator sets the test parameters via the PC (17). The commands are transmitted to the test bench controller (1).

[0036] The controller (1) sends a control signal to the speed controller (2), which switches the voltage from the battery (4) to the motor windings (5), causing it to rotate.

[0037] To generate a load, the controller (1) controls a current source (13), which supplies power to a single-winding transformer (8). The transformer's magnetic field induces eddy currents in a rotating copper disk (7), creating a contactless braking torque.

[0038] The reactive torque of the motor stator (5) is transmitted through the lever (9) to the stop (10) and then to the load cell (11). The signal from the load cell (11), proportional to the torque, is sent to the controller (1).

[0039] At the same time, the speed sensor (14) records the shaft speed, the voltage sensor (15) measures the battery voltage, and the shunt (16) measures the current consumption. All signals are received by the controller (1), digitized, and transmitted to the PC (17) for display and recording of the results.

[0040] Using this utility model expands the device's functionality by incorporating an electromagnetic braking system (copper disc and transformer), ensuring smooth and precise load regulation at high speeds without mechanical wear. Battery power allows for diagnostics of engine operation under conditions as close as possible to actual operation in electric vehicles, eliminating interference from mains power sources.

Claims

A test rig for high-speed brushless electric motors, comprising a test rig controller connected to a personal computer, a speed sensor, a system for measuring electrical parameters and a mechanical unit for mounting the motor, characterized in that a storage battery, a shunt, a speed controller, a controlled current source are additionally introduced, and the load unit is made in the form of a copper disk secured to the motor shaft, and a single-winding transformer connected to the controlled current source and installed with the possibility of contactless interaction with the disk, wherein the torque measuring system is made in the form of a lever secured to the motor and a strain gauge, the output of which is connected to the test rig controller, wherein the power supply to the motor is carried out from the storage battery through the shunt and the speed controller.

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