A system for testing the electromagnetic compatibility of electric drive systems using a hybrid dynamometer

Abstract

A system for testing the electromagnetic compatibility of an electric drive system using a hybrid power dynamometer includes an anechoic chamber, a wall panel connector disposed on the chamber wall of the anechoic chamber, one end of the wall panel connector being connected to a power source and the other end being used to connect to a motor controller, a hydraulic dynamometer disposed outside the anechoic chamber, a circular axial hole disposed in the chamber wall of the anechoic chamber, an insulating coupling disposed in the circular axial hole, a drive shaft of the hydraulic dynamometer being connected to one end of the insulating coupling, the other end of the insulating coupling being used to connect to a drive motor to be tested, and a power input shaft of the hydraulic dynamometer being connected to a power output shaft of an external power source.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic compatibility testing, and in particular to a system for testing the electromagnetic compatibility of an electric drive system by utilizing a hybrid power dynamometer. Background Art

[0002] A battery-electric vehicle (BEV) is a vehicle powered by an onboard electrical system that uses an electric drive system to propel its wheels. This system typically consists of a drive motor and a motor controller. When the drive motor is running, the system often generates alternating high-voltage, high-current signals, which can cause severe electromagnetic interference to the surrounding environment and easily affect the normal operation of the electric vehicle's electronic systems. Therefore, the electric drive system must undergo electromagnetic compatibility testing and implement necessary mitigation and protection measures to ensure that it meets electromagnetic compatibility requirements.

[0003] Currently, electromagnetic compatibility testing usually adopts the following two schemes:

[0004] ① Build an anechoic chamber to separate the drive motor to be tested from the electric dynamometer. The drive motor to be tested and the motor controller are placed inside the anechoic chamber, and the electric dynamometer is placed outside the anechoic chamber to prevent electromagnetic interference generated by the electric dynamometer from affecting the test results.

[0005] The disadvantage of this solution is that the motor shaft of the drive motor to be tested is connected to the input shaft of the electric dynamometer through a metal shaft (such as a stainless steel shaft) that passes through the wall of the anechoic chamber. When the metal shaft passes through the wall of the anechoic chamber, it will destroy the integrity of the anechoic chamber and affect the shielding effect of the anechoic chamber. Even if the part of the wall where the metal shaft passes is subjected to electromagnetic shielding at a high cost, electromagnetic leakage is still likely to occur. The shielding treatment is very difficult, and the test results are easily affected by electromagnetic interference.

[0006] ② A hydraulic dynamometer is used as a load and is placed inside the anechoic chamber together with the drive motor to be tested for testing. The disadvantage of this solution is that although the hydraulic dynamometer forms a load through water pressure and does not generate electromagnetic interference itself, the power of the hydraulic dynamometer is greatly limited because it forms a load through water pressure. When facing high-power working conditions, its speed and torque are far from meeting the test requirements and it is simply unable to provide sufficient power. Summary of the Invention

[0007] The purpose of the present invention is to address the corresponding deficiencies in the existing technology and provide a system for testing the electromagnetic compatibility of an electric drive system using a hybrid power dynamometer. By taking advantage of the fact that a hydraulic dynamometer does not generate electromagnetic interference, the hydraulic dynamometer is placed outside an anechoic chamber, and an additional power source is provided outside the anechoic chamber to provide the hydraulic dynamometer with additional power torque, thereby solving the problem of insufficient power of the hydraulic dynamometer under high-power conditions.

[0008] The objective of the present invention is achieved by adopting the following scheme: a system for testing the electromagnetic compatibility of an electric drive system using a hybrid power dynamometer, comprising an anechoic chamber, a wall panel connector arranged on the wall of the anechoic chamber, one end of the wall panel connector being connected to a power source, and the other end being used to connect to a motor controller, a hydraulic dynamometer being arranged outside the anechoic chamber, the wall of the anechoic chamber being provided with a circular axial hole, an insulating coupling being provided in the circular axial hole, a transmission shaft of the hydraulic dynamometer being connected to one end of the insulating coupling, the other end of the insulating coupling being used to connect to a drive motor to be tested, and a power input shaft of the hydraulic dynamometer being connected to a power output shaft of an external power source.

[0009] Preferably, the aperture of the circular shaft hole is obtained through an electromagnetic interference calibration experiment.

[0010] Preferably, the external power source is an engine.

[0011] Preferably, a bearing is provided in the circular shaft hole, and the insulating coupling is provided in the bearing.

[0012] Preferably, the power source is a battery simulator.

[0013] Preferably, the transmission shaft of the hydraulic dynamometer is connected to one end of the insulating coupling through a first connecting shaft, the other end of the insulating coupling is connected to one end of the second connecting shaft, and the other end of the second connecting shaft is used to connect to the drive motor to be tested. A shielding cover is provided on the wall of the anechoic chamber to shield the first connecting shaft, the insulating coupling, and the second connecting shaft.

[0014] Preferably, the first connecting shaft and the second connecting shaft are both made of carbon fiber.

[0015] Preferably, a conductive grounding ring is provided on the shielding cover to reduce shaft current.

[0016] Preferably, the cross section of the shielding cover is circular, and the center of the cross section of the shielding cover and the centers of the first connecting axis and the second connecting axis are collinear.

[0017] Preferably, the hydraulic dynamometer controller, hot water tank and cold water tank of the hydraulic dynamometer are all arranged outside the anechoic chamber, and the hydraulic dynamometer is connected to the hot water tank and the cold water tank respectively through two water pipes. Two waveguide tubes are respectively provided on the two water pipes for transmitting electromagnetic waves. The hydraulic dynamometer controller controls the hydraulic dynamometer through the water valves and water pumps arranged on the water pipes.

[0018] The beneficial effects of the present invention are as follows:

[0019] A hydraulic dynamometer is arranged outside the anechoic chamber. A circular shaft hole is provided on the wall of the anechoic chamber. An insulating coupling is provided in the circular shaft hole. The transmission shaft of the hydraulic dynamometer is connected to one end of the insulating coupling. The other end of the insulating coupling is used to connect to the drive motor to be tested. The power input shaft of the hydraulic dynamometer is connected to the power output shaft of an external power source. Taking advantage of the fact that the hydraulic dynamometer does not generate electromagnetic interference, the hydraulic dynamometer is placed outside the anechoic chamber, and an additional power source is provided outside the anechoic chamber to provide the hydraulic dynamometer with additional power and torque, which can meet the needs of most high-power working conditions.

[0020] Preferably, the aperture of the circular shaft hole is obtained through an electromagnetic interference calibration experiment, which can minimize the impact of the aperture of the circular shaft hole on the shielding effect of the anechoic chamber when performing electromagnetic compatibility testing on the drive motor.

[0021] Preferably, the external power source is an engine, and an engine with minimal electromagnetic interference is usually selected to provide additional power to the hydraulic dynamometer.

[0022] Preferably, the power source is a battery simulator, which can realistically simulate the electrical characteristics and electromagnetic environment of the electric drive system of an electric vehicle, ensure the reliability of the test results, and provide reliable evaluation test data for product development.

[0023] The transmission shaft of the hydraulic dynamometer is connected to one end of the insulating coupling through a first connecting shaft, the other end of the insulating coupling is connected to one end of the second connecting shaft, and the other end of the second connecting shaft is used to connect to the drive motor to be tested. A shielding cover is provided on the wall of the anechoic chamber to shield the first connecting shaft, the insulating coupling, and the second connecting shaft, thereby reducing electromagnetic interference in electromagnetic compatibility testing.

[0024] The first connecting shaft and the second connecting shaft are both made of carbon fiber, and have better shielding performance compared with traditional stainless steel shafts.

[0025] The shielding cover is provided with a conductive grounding ring, which is used in conjunction with the insulating coupling to reduce the shaft current to the greatest extent.

[0026] The advantages of the present invention are as follows:

[0027] ⑴ Provide additional power torque through an additional power source to solve the problem of insufficient power of the hydraulic dynamometer under high power conditions;

[0028] (2) The diameter of the circular shaft hole is obtained through electromagnetic interference calibration experiments, which greatly reduces the impact on the shielding effect of the anechoic chamber caused by the destruction of the integrity of the anechoic chamber;

[0029] ⑶ Since the external power source is supplemented by the power provided by the hydraulic dynamometer, it often does not need to run at full power to meet the needs of most high-power working conditions. The electromagnetic interference it generates will also be relatively reduced, and the shielding measures required will also be reduced, thereby greatly saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0031] like Figure 1 As shown, a system for testing the electromagnetic compatibility of an electric drive system using a hybrid dynamometer includes an anechoic chamber 1, a wall connector 5 mounted on the wall of the chamber 1, one end of the wall connector 5 connected to a power source 4, and the other end connected to a motor controller 3 mounted on a test table and equipped with a line impedance stabilization network. The power source 4 is a battery simulator. A hydraulic dynamometer 6 is mounted outside the chamber 1, and a circular axial hole is defined in the wall of the chamber 1. The diameter of the circular axial hole is determined through electromagnetic interference calibration experiments. An insulating coupling is mounted within the circular axial hole via a bearing. The drive shaft 16 of the hydraulic dynamometer 6 is connected to one end of the insulating coupling, and the other end of the insulating coupling is connected to the drive motor 2 to be tested on a test bench. The power input shaft 15 of the hydraulic dynamometer 6 is connected to the power output shaft of an external power source 12, forming the hybrid dynamometer.

[0032] The external power source 12 is an engine. The hydraulic dynamometer controller 11, hot water tank 10, and cold water tank 14 of the hydraulic dynamometer 6 are all arranged outside the anechoic chamber 1. The hydraulic dynamometer 6 is connected to the hot water tank 10 and the cold water tank 14 respectively through two water pipes 7. Two waveguide tubes 8 are respectively provided on the two water pipes 7 for transmitting electromagnetic waves. The hydraulic dynamometer controller 11 controls the hydraulic dynamometer 6 through the water valve 9 and water pump 13 arranged on the water pipes 7.

[0033] In this embodiment, the transmission shaft 16 of the hydraulic dynamometer 6 is connected to one end of the insulating coupling through the first connecting shaft, the other end of the insulating coupling is connected to one end of the second connecting shaft, and the other end of the second connecting shaft is connected to the drive motor 2 to be tested. A shielding cover is provided on the wall of the anechoic chamber 1 for shielding the first connecting shaft, the insulating coupling, and the second connecting shaft. The first connecting shaft and the second connecting shaft are both made of carbon fiber. A conductive grounding ring is provided on the shielding cover for reducing the shaft current. The cross-section of the shielding cover is circular, and the center of the cross-section of the shielding cover and the axis centers of the first connecting shaft and the second connecting shaft are collinear.

[0034] Before performing an electromagnetic compatibility test on the drive motor to be tested, the diameter of the circular shaft hole should be determined through an electromagnetic interference calibration experiment. The specific steps are as follows:

[0035] ① Taking into account the radial runout of the shaft and installation issues during the electromagnetic compatibility test, the diameter D of the insulating coupling cross section determines the aperture range of the circular shaft hole. For example, in this embodiment, the aperture range of the circular shaft hole is D+30mm to D+90mm, where D is the diameter of the insulating coupling cross section.

[0036] ② In the electromagnetic interference calibration experiment, within the aperture range determined in step ①, adjust the aperture size of the circular shaft hole, compare the electromagnetic interference intensity at different apertures, and select the aperture corresponding to the minimum electromagnetic interference intensity as the aperture of the circular shaft hole. In this embodiment, the diameter D of the cross section of the insulating coupling is 330 mm. Through electromagnetic simulation analysis and calculation, when the aperture of the circular shaft hole is 390 mm, the field strength value is reduced by 10 dbv / m. At this time, the electromagnetic interference intensity is the minimum, which can ensure the shielding effectiveness of most frequency bands.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A system for testing the electromagnetic compatibility of an electric drive system using a hybrid dynamometer, comprising an anechoic chamber (1), a wall panel connector (5) arranged on the wall of the anechoic chamber (1), one end of the wall panel connector (5) being connected to a power source (4), and the other end being used to connect to a motor controller, characterized in that: A hydraulic dynamometer (6) is arranged outside the anechoic chamber (1), a circular shaft hole is provided on the wall of the anechoic chamber (1), an insulating coupling is provided in the circular shaft hole, a transmission shaft (16) of the hydraulic dynamometer (6) is connected to one end of the insulating coupling, the other end of the insulating coupling is used to connect to a drive motor to be tested, and a power input shaft (15) of the hydraulic dynamometer (6) is connected to a power output shaft of an external power source (12); The diameter of the circular shaft hole is obtained through an electromagnetic interference calibration experiment; A bearing is provided in the circular shaft hole, and the insulating coupling is provided in the bearing; The transmission shaft (16) of the hydraulic dynamometer (6) is connected to one end of the insulating coupling via a first connecting shaft, the other end of the insulating coupling is connected to one end of a second connecting shaft, and the other end of the second connecting shaft is used to connect to the drive motor to be tested, and a shielding cover is provided on the wall of the anechoic chamber (1) for shielding the first connecting shaft, the insulating coupling, and the second connecting shaft; The hydraulic dynamometer controller (11), the hot water tank (10), and the cold water tank (14) of the hydraulic dynamometer (6) are all arranged outside the anechoic chamber (1). The hydraulic dynamometer (6) is connected to the hot water tank (10) and the cold water tank (14) respectively through two water pipes (7). Two waveguide tubes (8) are respectively provided on the two water pipes (7) for transmitting electromagnetic waves. The hydraulic dynamometer controller (11) controls the hydraulic dynamometer (6) through the water valve (9) and the water pump (13) provided on the water pipes (7).

2. The system according to claim 1, wherein: The external power source (12) is an engine.

3. The system according to claim 1, wherein: The power source (4) is a battery simulator.

4. The system according to claim 1, wherein: The first connecting shaft and the second connecting shaft are both made of carbon fiber.

5. The system according to claim 1, wherein: The shielding cover is provided with a conductive grounding ring for reducing shaft current.

6. The system according to claim 1, wherein: The cross section of the shielding cover is circular, and the center of the cross section of the shielding cover and the axis centers of the first connecting axis and the second connecting axis are collinear.

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