AC drive with adjustable intermediate DC link voltage for test bench and test method

Abstract

The application discloses an AC transmission pair-drag test bed with adjustable intermediate DC link voltage and a test method, which comprises a measured motor, a test motor, an instruction input unit, an adjustable power supply unit, a test traction variable flow control unit and a measured traction variable flow control unit. The instruction input unit is used for realizing communication transmission and setting of running direction, running condition, handle level and running speed; the adjustable power supply unit is used for providing the intermediate DC link voltage required by work; the test traction variable flow control unit controls the test motor to run to a target speed point and carries out constant speed control; and the measured traction variable flow control unit is used for real-time inquiry of running condition, handle level, real-time speed reference value and torque relation curve to control the output torque of the measured motor. The application provides a dynamic characteristic test environment for the intermediate DC link voltage, increases the dynamic characteristic of the AC transmission pair-drag test bed and makes the test process more close to the running environment of the diesel locomotive and diesel motor train unit.

Description

Technical Field

[0001] This invention relates to the field of AC drive testing technology for rail transit, specifically to an AC drive test bench and test method with adjustable intermediate DC link voltage. Background Technology

[0002] AC drive test benches, serving as experimental platforms for the control and algorithm research of high-power AC motors, have been widely used in the rail transit field. In the traction converter control of AC drive locomotives and EMUs, diesel locomotives and EMUs are powered by diesel generator sets, which output intermediate DC link voltage after rectification. Electric locomotives, on the other hand, draw power from the high-voltage grid via a pantograph, which is then converted by a transformer to output AC power, which is then controlled by a four-quadrant module to output intermediate DC link voltage. This intermediate DC link voltage provides the voltage required for traction motor control. The intermediate DC link voltage of a diesel locomotive varies with the setting of the driver's control handle position and the operating speed. For diesel locomotives and EMUs with a fixed number of driver control handle positions, the intermediate DC link voltage may consist of multiple varying curves; however, for diesel locomotives with stepless driver control handle positions, the intermediate DC link voltage will consist of countless varying curves. Figure 2 The figure shows the voltage curve of the intermediate DC link in the traction condition of a certain diesel locomotive (with 8 handle levels) as a function of handle level and speed point.

[0003] AC drive test benches are used to provide a simulated operating environment for the traction motors used in locomotives. They typically employ a two-motor configuration: one is the motor under test, and the other is a support motor. The two motors are connected by a coupling to achieve synchronous rotation. The support motor provides constant speed control, used to set the operating speed point of the traction motor under test. The motor under test and the support motor share an intermediate DC link voltage, and the required energy source is generally a voltage regulating power supply.

[0004] In existing AC drive test benches, there is generally no driver control handle position device. The voltage regulating power supply device adopts a manual adjustment method. According to the test speed required by the motor under test and the test handle position, the expected value of the intermediate DC link voltage corresponding to the operating condition of the traction motor is manually set. After setting, the running speed of the test motor is set to meet the operating conditions of the motor under test.

[0005] The method of manually adjusting the intermediate DC link voltage provides the tested traction motor with an intermediate DC link voltage at a specific handle position and speed point. This method is very suitable for urban rail vehicles or electric locomotives where the intermediate DC link voltage is fixed. However, for diesel locomotives, the intermediate DC link voltage varies with operating conditions, handle position, and locomotive speed. This requires constant voltage adjustment, which is not only labor-intensive but also slow and has low accuracy. When a load is applied, if the energy required by the load is large, the target voltage will fluctuate and is not easily stabilized at the set fixed point. Manually adjusting the intermediate DC link voltage typically involves first adjusting the voltage to the target value and then setting the test motor speed to the target value. This method can only test the motor's operating characteristics at a fixed point and cannot achieve rapid switching between different handle positions or rapid adjustment at different speed points. Furthermore, the testing environment provided by the test bench for manually adjusting the intermediate DC link voltage differs significantly from the actual operating environment of diesel locomotives and diesel multiple units.

[0006] Patent technology ZL201410625298.5, "A Dual Power Supply and Energy Feedback System for Motor Drive," provides a dual power supply and energy feedback system for motor drive, including: a dual power supply switching circuit connected between the dual power supply and the inverter, used to switch the operating mode of the dual power supply (power supply mode, charging mode, mutual feeding mode, or power supply / mutual feeding mode). This system does not involve power output voltage control. It cannot address the power supply variation requirements of AC drive test benches for diesel locomotives and diesel multiple units.

[0007] Therefore, existing technologies still need improvement. Summary of the Invention

[0008] The main objective of this invention is to provide an AC drive test bench and test method with adjustable intermediate DC link voltage, in order to solve the technical problem that the test environment of the existing test bench is significantly different from the actual operating environment of diesel locomotives and diesel multiple units.

[0009] According to one aspect of the present invention, an AC drive counter-drive test bench with adjustable intermediate DC link voltage is provided, comprising:

[0010] The motor under test is the traction motor of the vehicle model under test;

[0011] The test motor is connected to the motor under test via a coupling, and at the same speed point, the test motor can output a maximum torque greater than or equal to the maximum torque of the motor under test.

[0012] The instruction input unit is used to realize communication transmission and to set the running direction, operating conditions, handle position and running speed of the diesel locomotive and diesel multiple unit.

[0013] An adjustable power supply unit is used to provide the intermediate DC link voltage required for the operation of the test motor and the motor under test.

[0014] The accompanying traction converter control unit controls the accompanying motor to run to the target speed point according to the direction signal and the real-time speed reference value, performs constant speed control, and ensures that the accompanying motor always runs at the real-time speed reference value Spd_Ref, regardless of the torque output of the tested motor.

[0015] The traction converter control unit under test is used to query the operating conditions, handle position, real-time speed reference value and torque relationship curve in real time to control the output torque Tq_Ref of the motor under test.

[0016] Furthermore, the instruction input unit includes a human-machine interface, a driver controller, and an instruction input controller.

[0017] The driver controller is the driver controller of the vehicle model under test, used to send signals of the running direction, operating conditions and handle position of the diesel locomotive and diesel multiple unit;

[0018] The human-machine interface is used for setting speed commands for diesel locomotives and diesel multiple units.

[0019] The command input controller is used to send the real-time speed reference value Spd_Ref, as well as the handle position signal of the diesel locomotive and diesel multiple unit, the running direction, and the running condition to the adjustable power supply unit, the traction converter control unit under test, and the traction converter control unit under test in real time via communication.

[0020] Furthermore, the speed command setting includes the setting of target speed, acceleration, deceleration, maximum acceleration, and maximum deceleration;

[0021] Among them, the acceleration setting value cannot be greater than the maximum acceleration value. If the acceleration input value is greater than the maximum acceleration value, it will automatically default to the maximum acceleration value. The absolute value of the deceleration setting value cannot be greater than the absolute value of the maximum deceleration value. If the absolute value of the deceleration input value is greater than the absolute value of the maximum deceleration value, it will automatically default to the maximum deceleration value.

[0022] Furthermore, the adjustable power supply unit includes a transformer and a power controller;

[0023] The transformer is used to convert industrial electricity into the required alternating current.

[0024] The power controller is used to output AC power to the target DC link voltage.

[0025] Furthermore, the motor under test and the accompanying motor are mechanically coaxial and have the same rotation speed. The operating speed of the motor under test is controlled by the accompanying motor, and the output torque of the motor under test is controlled by the traction converter control unit under test.

[0026] On the other hand, embodiments of the present invention also disclose a test method for an AC drive-assisted test bench with an adjustable intermediate DC link voltage, comprising:

[0027] The motor and driver controller of the vehicle model under test are installed on the AC drive anti-trailer test bench;

[0028] The command input controller collects the hardware signals of the driver controller and obtains the corresponding operating conditions, handle position and direction signals according to the combination of the handle position signals of the diesel locomotive or diesel multiple unit on which the tested motor is installed.

[0029] Speed ​​commands are set via a human-machine interface;

[0030] The command input controller will send the operating conditions, handle position and direction signals, as well as the speed set value with the set acceleration or deceleration as the rate of change, to the adjustable power supply unit, the traction converter control unit under test and the traction converter control unit under test in real time via communication.

[0031] The adjustable power supply unit obtains the target value for the intermediate DC link voltage control by looking up the voltage curve table of the diesel locomotive or diesel multiple unit, and achieves the matching of the output voltage with the target value through its own control.

[0032] The test traction converter control unit operates the test motor at the target speed based on the direction signal and real-time speed reference value;

[0033] The traction converter control unit under test controls the traction motor to output torque according to the corresponding torque setpoint.

[0034] Furthermore, the speed command setting includes setting a target running speed value and an acceleration value. The acceleration value is set with an upper limit, which cannot exceed the actual motor acceleration and deceleration limits.

[0035] Furthermore, as the operating conditions, handle position, direction signal, or speed command change, the adjustable power supply unit changes its output voltage amplitude to provide a variable intermediate DC link voltage for the test motor and the motor under test. The traction converter control unit under test and the traction converter control unit under test also change accordingly with the operating conditions, handle position, direction signal, and speed command, thereby providing an automated testing environment for the traction control unit under test.

[0036] Furthermore, the driver controller enables the selection of traction, electric braking, and coasting operation modes.

[0037] Furthermore, the traction or electric control handle position can be set by configuring the handle position.

[0038] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0039] This invention provides an AC drive test bench and test method with adjustable intermediate DC link voltage, which is used for performance debugging of traction motors used in locomotives. It provides a dynamic characteristic test environment for intermediate DC link voltage, increases the dynamic characteristics of the AC drive test bench, and makes the test process closer to the actual operating environment of diesel locomotives and diesel multiple units. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This diagram shows a structural schematic of an AC drive counter-drive test bench with adjustable intermediate DC link voltage as disclosed in some embodiments of the present invention.

[0042] Figure 2 The diagram shows the variation of the intermediate DC link voltage with the handle position and speed point under a certain internal combustion locomotive traction condition in the AC drive anti-tow test method with adjustable intermediate DC link voltage disclosed in some embodiments of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0044] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0045] like Figure 1As shown, some embodiments of the present invention disclose an AC drive test bench with adjustable intermediate DC link voltage, wherein the AC drive test bench is replaced with a driver controller and a test motor provided by the vehicle model of the motor being tested. The system includes a test motor, a companion motor, a command input unit, an adjustable power supply unit, a companion traction converter control unit, and a test traction converter control unit. The test motor is the traction motor of the vehicle model under test. The companion motor and the test motor are connected by a coupling, and at the same speed point, the maximum torque output of the companion motor is greater than or equal to the maximum torque output of the test motor. The command input unit is used for communication transmission and setting the running direction, operating conditions, handle position, and running speed of the diesel locomotive / diesel multiple unit. The adjustable power supply unit provides the intermediate DC link voltage required for the operation of the companion motor and the test motor. The companion traction converter control unit controls the companion motor to run to the target speed point based on the direction signal and real-time speed reference value, performing constant speed control and ensuring that the companion motor always runs at the real-time speed reference value Spd_Ref regardless of the torque output of the test motor. The test traction converter control unit is used to query the operating conditions, handle position, and real-time speed-torque relationship curve in real time to control the output torque Tq_Ref of the test motor. This embodiment can be used for performance debugging of traction motors used in locomotives, providing a dynamic characteristic testing environment for intermediate DC link voltage, increasing the dynamic characteristics of AC drive test benches, and making the test process closer to the operating environment of diesel locomotives and diesel multiple units.

[0046] The AC drive test bench with adjustable intermediate DC link voltage disclosed in some embodiments of the present invention, based on the above embodiments, includes a human-machine interface, a driver controller, and a command input controller in the command input unit. The driver controller is the driver controller of the vehicle model under test, used to issue the running direction, running condition, and handle position signals of the diesel locomotive and diesel multiple unit. The human-machine interface is used for setting the speed commands of the diesel locomotive and diesel multiple unit. The command input controller is used to send the real-time speed reference value Spd_Ref, as well as the handle position signals, running direction, and running condition of the diesel locomotive and diesel multiple unit, to the adjustable power supply unit, the traction converter control unit under test, and the traction converter control unit under test in real time via communication. The speed command settings include setting the target speed, acceleration, deceleration, maximum acceleration, and maximum deceleration. The acceleration setting value cannot exceed the maximum acceleration value; if the input acceleration value is greater than the maximum acceleration value, it automatically defaults to the maximum acceleration value. Similarly, the absolute value of the deceleration setting value cannot exceed the absolute value of the maximum deceleration value; if the absolute value of the input deceleration value is greater than the absolute value of the maximum deceleration value, it automatically defaults to the maximum deceleration value. The adjustable power supply unit includes a transformer and a power controller. The transformer converts industrial power to the required AC power; the power controller outputs the intermediate DC voltage link from the AC power.

[0047] To increase the compatibility of the AC drive test bench with different types of driver controllers (8-position handles, 12-position handles, and no-position handles) used in diesel locomotives and diesel multiple units, the command input controller collects the hardware signals of the driver controller. The hardware acquisition channel of the command input controller is compatible with multiple driver controllers, and the hardware signals are used to obtain the corresponding operating conditions, handle positions, and direction signals according to the combination of handle position signals of the diesel locomotive or diesel multiple unit on which the motor under test is installed. The target speed and acceleration values ​​are set via a human-machine interface. An upper limit is set for the acceleration, which cannot exceed the actual acceleration and deceleration limits of the motor. The command input controller transmits the detected operating conditions, direction signals, handle position signals, and real-time speed reference values ​​with the set acceleration or deceleration rate as the rate of change to the adjustable power supply unit, the tested traction converter control unit, and the accompanying traction converter control unit in real time via communication. The adjustable power supply unit receives the operating conditions, handle position, and direction signals, as well as the operating speed signal, set by the external driver controller or the human-machine interface. It then locates the electrical circuit of the diesel locomotive or diesel multiple unit. The pressure curve table is used to obtain the target value of the intermediate DC link voltage control at this time. The output voltage is matched to the target value through its own control. Simultaneously, the operating condition, direction signal, handle position, and locomotive speed signals are sent to the converter control unit of the motor under test and the converter control unit of the traction motor under test. The converter control unit of the traction motor under test receives the speed command signal and operates at the real-time speed reference value. The converter control unit of the traction motor under test receives the command signal and controls the traction motor to output the corresponding torque setpoint according to the torque value corresponding to the operating condition, direction signal, handle position, and real-time speed reference value, and controls the output torque of the motor under test to reach the torque setpoint value. This achieves the towing control of the AC drive test bench. As the operating condition, handle position, or speed command changes, the adjustable power supply unit changes its output voltage amplitude to provide a variable intermediate DC link voltage for the towing motor. The converter control units of the motor under test and the traction motor under test also change accordingly, thus providing an automated testing environment for the traction control unit under test. The motor under test and the accompanying motor are mechanically coaxial and have the same rotation speed. The operating speed of the motor under test is controlled by the accompanying motor, and the output torque of the motor under test is controlled by the traction converter control unit under test.

[0048] Some embodiments of the present invention also disclose a test method for AC drive with adjustable intermediate DC link voltage, including:

[0049] The traction motor and driver controller of the vehicle model under test are installed on the AC drive anti-trailer test bench;

[0050] The command input controller collects the hardware signals of the driver controller and obtains the corresponding operating conditions, handle position and direction signals according to the combination of the handle position signals of the diesel locomotive or diesel multiple unit on which the tested motor is installed.

[0051] Speed ​​commands are set via a human-machine interface;

[0052] The command input controller will send the obtained operating conditions, handle position and direction signals, as well as the real-time speed reference value with a set acceleration or deceleration rate, to the adjustable power supply unit, the traction converter control unit under test and the traction converter control unit under test in real time via communication.

[0053] The adjustable power supply unit obtains the target voltage control of the intermediate DC link by looking up the voltage curve table of the diesel locomotive or diesel multiple unit, and achieves the matching of the output voltage with the target value through its own control.

[0054] The test traction converter control unit keeps the test motor running at the real-time speed reference value based on the direction signal and the real-time speed reference value.

[0055] The traction converter control unit under test controls the traction motor to output torque according to the corresponding torque setpoint.

[0056] The speed command setting includes setting a target operating speed value and an acceleration value. The acceleration value is set with an upper limit, which cannot exceed the actual motor acceleration and deceleration limits.

[0057] As the operating conditions, handle position, direction signal, or speed command change, the adjustable power supply unit adjusts its output voltage amplitude to provide a variable intermediate DC link voltage for both the test motor and the motor under test. The traction converter control unit under test and the test traction converter control unit also change accordingly based on the operating conditions, handle position, direction signal, and speed command, thus providing an automated testing environment for the traction control unit under test. The driver's controller can be used to select between traction, electric braking, and coasting operating conditions. The handle position can be set to either traction or electric braking.

[0058] It should be noted that some of the devices mentioned in the embodiments of the present invention use hard wiring while others use communication methods. Although the signal acquisition methods differ, the same effect can be achieved. At the same time, this solution also meets the testing requirements of maintaining a constant voltage in intermediate DC links for urban rail vehicles, electric locomotives, and other similar applications.

[0059] In some embodiments of the present invention, the AC drive counter-rotating test bench consists of an instruction input unit, an adjustable power supply unit, a companion traction converter control unit, a tested traction converter control unit, and a tested motor and a companion motor connected by a coupling. Among them, the instruction input unit realizes the setting and communication transmission of the running direction, running conditions, handle position, and running speed of diesel locomotives and diesel multiple units. It consists of a human-machine interface, a driver controller, and an instruction input controller. The running direction and handle position signals of diesel locomotives and diesel multiple units are sent by the driver controllers used by diesel locomotives and diesel multiple units. The human-machine interface is used for setting the target speed of diesel locomotives and diesel multiple units, and is configured with target speed, acceleration, deceleration, maximum acceleration, and maximum deceleration. The acceleration setting value cannot be greater than the maximum acceleration value. If the input acceleration value is greater than the maximum acceleration value, it is automatically defaulted to the maximum acceleration value, and the same applies to the deceleration value. The instruction input controller collects the target speed Spd_target, acceleration A+, and deceleration A-, and judges the difference between the motor running speed Spd_Fbk and the target speed Spd_target at this time. If Spd_target>Spd_Fbk, the instruction input controller changes according to the acceleration A+ rate. If Spd_target<Spd_Fbk, the instruction input controller changes according to the deceleration A- rate to obtain the output speed value Spd_Ref at each moment until Spd_Ref = Spd_target. The instruction input controller sends the real-time speed reference value Spd_Ref, the handle position signal, running direction, and running conditions of diesel locomotives and diesel multiple units to the adjustable power supply unit, the tested traction converter control unit, and the companion traction converter control unit in real time through communication to ensure the synchronization of instructions.

[0060] The adjustable power supply unit consists of a transformer and a power supply controller. The transformer realizes the conversion of industrial 380V AC power to the required AC power. The power supply controller realizes the output of AC power to the target intermediate DC link voltage. By receiving the handle position, running direction, and real-time speed reference value Spd_Ref instructions, it queries the traction / electric braking intermediate DC link voltage reference value curve in real time and outputs the target value of the intermediate DC link voltage corresponding to the corresponding handle position and real-time speed reference value in the running mode of diesel locomotives and diesel multiple units to provide the intermediate DC link voltage required for the operation of the companion motor and the tested motor.

[0061] The companion traction converter control unit consists of a companion traction converter controller and a companion traction converter power module. When receiving the direction signal and speed signal, the companion traction converter controller controls the companion motor to rotate forward or backward according to the direction signal and runs to the target speed point for constant speed control, and ensures that the companion motor always runs at the real-time speed reference value Spd_Ref regardless of the torque output of the tested motor.

[0062] The tested traction converter control unit consists of a tested traction converter controller and a tested traction converter power module. The tested traction converter controller controls the output torque Tq_Ref of the tested motor by querying the relationship curve between the tested operating conditions, handle position, real-time speed reference value Spd_Ref and torque through the detected operating conditions, handle position, real-time speed reference value and torque. The traction motor and the test motor are mechanically coaxial and have the same speed. The operating speed of the tested motor is controlled by the test motor, and the output torque is controlled by the tested traction converter controller.

[0063] The driver controller used in diesel locomotives and diesel multiple units (EMUs) can select traction, electric braking, and coasting modes, and can also set the traction or electric braking handle position through the handle level settings. The driver controller used in the AC drive test bench adopts the original driver controller from the locomotive and EMU, ensuring the consistency of signal input information. The handle position determines the operating conditions and handle level of the AC drive test bench. The control of the input commands of the AC drive test bench is completed by the handle position and speed settings, and the synchronous transmission of communication methods realizes the synchronous control of the adjustable power supply unit, the test traction converter control unit, and the tested traction converter control unit.

[0064] The AC drive test bench and test method with adjustable intermediate DC link voltage disclosed in the embodiments of the present invention are actually implemented by the driver controller used in locomotives and EMUs, completely replicating the operating conditions of diesel locomotives and diesel EMUs. The adjustable power supply unit automatically outputs the desired intermediate DC link voltage according to the setting of the handle position and speed point, with fast response speed. Compared with the prior art, it is more in line with the actual operating conditions and can realize the rapid switching of different handle positions and the frequency sweep setting of different speed points at the same handle position required by the AC drive test bench.

[0065] In summary, the AC drive test bench and test method disclosed in this invention require the tested motor and driver controller to be provided according to the vehicle model used and installed in the AC drive test bench. To increase the compatibility of the AC drive test bench with different types of driver controllers (8-position handles, 12-position handles, and no positions) used in diesel locomotives and diesel multiple units, the command input controller collects the driver controller hardware signals and obtains the corresponding operating conditions, handle positions, and direction signals according to the combination of handle position signals of the locomotive or multiple unit on which the tested motor is installed. The operating speed point is set via a human-machine interface. The command input controller detects the operating condition, direction signal, handle position signal, and real-time speed reference value with a set acceleration or deceleration rate of change, and sends them in real time to the adjustable power supply unit, the traction converter control unit under test, and the traction converter control unit under test to ensure the synchronization and consistency of commands from all units of the AC drive test bench. The adjustable power supply unit receives the handle position, operating condition, and speed signal commands, and outputs the target value of the intermediate DC link voltage corresponding to the handle position and real-time speed reference value under the corresponding operating mode of the diesel locomotive and diesel multiple unit, by looking up the intermediate DC link voltage meter, so as to provide the intermediate DC link voltage required for the operation of the assisted motor and the motor under test.

[0066] It should be noted that the components or steps in the above embodiments can be interleaved, substituted, added, or deleted. Therefore, the combinations formed by these reasonable permutations and transformations should also fall within the protection scope of the present invention, and the protection scope of the present invention should not be limited to the above embodiments.

[0067] The above are exemplary embodiments disclosed in this invention. The order of the disclosed embodiments is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. However, it should be noted that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this invention (including the claims) is limited to these examples. Various changes and modifications can be made without departing from the scope defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular.

[0068] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A test bench for AC drive coupling with adjustable intermediate DC link voltage, characterized in that, include: The motor under test is the traction motor of the vehicle model under test; The test motor is connected to the motor under test via a coupling, and at the same speed point, the maximum torque output by the test motor must be greater than or equal to the maximum torque of the motor under test. The instruction input unit is used to realize communication transmission and to set the running direction, operating conditions, handle position and running speed of the diesel locomotive and diesel multiple unit. An adjustable power supply unit is used to provide the intermediate DC link voltage required for the operation of the test motor and the motor under test. The accompanying traction converter control unit is used to control the accompanying motor to run to the target speed point according to the running direction and real-time speed reference value, to perform constant speed control, and to ensure that the accompanying motor always runs at the real-time speed reference value Spd_Ref, regardless of the torque output of the tested motor. The traction converter control unit under test is used to query the operating conditions, handle position, real-time speed reference value and torque relationship curve in real time to control the output torque Tq_Ref of the motor under test. The command input unit includes a command input controller, which is used to send the real-time speed reference value Spd_Ref, as well as the handle position signal of the diesel locomotive and diesel multiple unit, the running direction, and the running condition to the adjustable power supply unit, the traction converter control unit under test, and the traction converter control unit under test in real time via communication.

2. The AC drive test bench with adjustable intermediate DC link voltage according to claim 1, characterized in that, The instruction input unit also includes a human-machine interface and a driver controller. The driver controller is the driver controller of the vehicle model under test, used to send signals of the running direction, operating conditions and handle position of the diesel locomotive and diesel multiple unit; The human-machine interface is used for setting speed commands for diesel locomotives and diesel multiple units.

3. The AC drive test bench with adjustable intermediate DC link voltage according to claim 2, characterized in that, The speed command settings include the settings for target speed, acceleration, deceleration, maximum acceleration, and maximum deceleration; Among them, the acceleration setting value cannot be greater than the maximum acceleration value. If the acceleration input value is greater than the maximum acceleration value, it will automatically default to the maximum acceleration value. The absolute value of the deceleration setting value cannot be greater than the absolute value of the maximum deceleration value. If the absolute value of the deceleration input value is greater than the absolute value of the maximum deceleration value, it will automatically default to the maximum deceleration value.

4. The AC drive test bench with adjustable intermediate DC link voltage according to claim 1, characterized in that, The adjustable power supply unit includes a transformer and a power controller; The transformer is used to convert industrial electricity into the required alternating current. The power controller is used to output the DC link voltage between the AC power supply and the target.

5. The AC drive test bench with adjustable intermediate DC link voltage according to claim 1, characterized in that, The motor under test and the accompanying motor are mechanically coaxial and have the same rotation speed. The operating speed of the motor under test is controlled by the accompanying motor, and the output torque of the motor under test is controlled by the traction converter control unit under test.

6. A test method using the AC drive coupling test bench with adjustable intermediate DC link voltage as described in any one of claims 1-5, characterized in that, include: The traction motor and driver controller of the vehicle model under test are installed on the AC drive anti-trailer test bench; The command input controller collects the hardware signals of the driver controller and obtains the corresponding operating conditions, handle positions and direction signals according to the combination of the handle position signals of the diesel locomotive or diesel multiple unit on which the tested motor is installed. Speed ​​commands are set via a human-machine interface; The command input controller will send the operating conditions, handle position and direction signals, as well as the speed set value with the set acceleration or deceleration as the rate of change, to the adjustable power supply unit, the traction converter control unit under test and the traction converter control unit under test in real time via communication. The adjustable power supply unit obtains the target value for the intermediate DC link voltage control by looking up the voltage curve table of the diesel locomotive or diesel multiple unit, and achieves the matching of the output voltage with the target value through its own control. The test traction converter control unit operates the test motor at the target speed based on the direction signal and real-time speed reference value; The traction converter control unit under test controls the traction motor to output torque according to the corresponding torque setpoint.

7. The test method according to claim 6, characterized in that, The speed command setting includes setting a target operating speed value and an acceleration value. The acceleration value is set with an upper limit, which cannot exceed the actual motor acceleration and deceleration limits.

8. The test method according to claim 6, characterized in that, As the handle position, direction signal, and speed command change, the adjustable power supply unit changes its output voltage amplitude to provide a variable intermediate DC link voltage for the test motor and the motor under test. The traction converter control unit under test and the traction converter control unit under test also change accordingly with the operating conditions, handle position, direction signal, and speed command, thereby providing an automated testing environment for the traction control unit under test.

9. The test method according to claim 6, characterized in that, The driver's controller enables the selection of traction, electric braking, and coasting operation modes.

10. The test method according to claim 6, characterized in that, The traction or electric control handle position can be set by adjusting the handle position.

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