Brake unit test system

Abstract

According to one embodiment of the utility model, the test system of the brake unit comprises a first motor and a second motor, the first motor is connected with the second motor through a connecting shaft, the first motor is connected with a first control system, the second motor is connected with a second control system, and the first control system is connected with the second control system. The second control system comprises a direct current bus which is suitable for receiving feedback energy of the second motor. And the braking unit is connected with the direct current bus of the second control system and is set to start a braking mode of energy loss through the braking resistor when the feedback energy received by the direct current bus voltage is reached. The test system not only can realize the load test of the brake unit, but also can realize the function test of the brake unit, and the test system is closer to the actual working condition.

Description

Technical Field

[0001] This utility model relates to the field of electronic power, and more specifically, to a braking unit testing system. Background Technology

[0002] Braking units are typically used in electronic devices such as frequency converters or servo drives to dissipate feedback energy, achieve rapid braking, and stabilize system operation.

[0003] Testing of braking units typically involves load testing and functional testing. Load testing includes full-load testing and overload testing, while functional testing verifies its ability to regulate the DC bus voltage. Existing testing systems usually use a rectifier connected to the braking unit under test to force it to operate. This method can easily achieve load testing of the braking unit, but it cannot perform functional testing. Utility Model Content

[0004] In view of this, the present invention proposes a braking unit testing system to at least solve all or part of the above problems.

[0005] According to an embodiment of the present invention, a braking unit testing system includes a braking unit to be tested connected to a braking resistor. The testing system further includes a first motor and a second motor, which are connected by a shaft. The first motor is connected to a first control system, and the second motor is connected to a second control system. The second control system includes a DC bus adapted to receive feedback energy from the second motor. The braking unit is connected to the DC bus of the second control system and is configured to activate a braking mode that dissipates energy through the braking resistor when the DC bus voltage receives the feedback energy and reaches a first preset energy.

[0006] Furthermore, when the braking unit is subjected to a load test, both the first motor and the second motor are in a standby state, and the braking unit is configured to activate the braking mode under the action of the second control system.

[0007] Furthermore, the first motor is configured to operate in speed control mode under the action of the first control system, and the second motor is configured to operate in torque control mode under the action of the second control system, and generate the feedback energy, wherein the rotation direction of the first motor is opposite to the torque direction of the second motor.

[0008] Furthermore, the feedback energy is achieved based on the adjustment of the torque of the second motor.

[0009] Furthermore, the test system also includes a PWM duty cycle adjustment circuit, which is connected to the braking unit and is adapted to adjust the PWM duty cycle of the braking unit.

[0010] Furthermore, the first control system includes a first rectifier and a first inverter connected in sequence, and the first motor is connected to the output terminal of the first inverter.

[0011] Furthermore, the second control system includes a second rectifier and a second inverter connected in sequence, and the second motor is connected to the input terminal of the second inverter. The second rectifier does not have an energy feedback function.

[0012] Furthermore, the braking unit also includes a braking unit input terminal and a braking unit output terminal, which are respectively connected to the positive DC bus and negative DC bus of the DC bus via protection devices.

[0013] Furthermore, both the first motor and the second motor are AC motors.

[0014] As can be seen from the above technical solution, the braking unit testing system according to this utility model embodiment uses two motors, a first motor and a second motor, to support the braking unit. The first motor is controlled by a first control system, and the second motor is controlled by a second control system. The braking unit is connected to the DC bus in the second control system. This allows for load testing of the braking unit using the second control system alone, or it can be combined with other systems. By controlling the first motor in speed control mode and the second motor in torque control mode, the PWM duty cycle of the braking unit and the feedback energy of the second motor can be adjusted to perform functional testing of the braking unit. Furthermore, the testing system based on this utility model more closely reflects the actual operating conditions of the braking unit, resulting in more accurate test results. Attached Figure Description

[0015] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can more clearly understand the above and other features and advantages of the present invention, in which:

[0016] Figure 1 This is a schematic diagram of the circuit structure of a testing system for a prior art braking unit according to an embodiment of the present invention;

[0017] Figure 2 This is a circuit diagram of a testing system for a braking unit according to an embodiment of the present invention.

[0018] The reference numerals in the attached figures are as follows:

[0019] 1. Braking unit; 2. Braking resistor; 11. First motor; 12. Second motor

[0020] 21 First Control System 22 Second Control System 31 First Rectifier 41 First Inverter 32 Second Rectifier 42 Second Inverter 50 Protection Devices 100 Third Rectifier Detailed Implementation

[0021] To make the objectives, technical solutions and advantages of this utility model clearer, the following embodiments will be used to further describe this utility model in detail.

[0022] Figure 1 This is a schematic diagram of the circuit structure of a prior art braking unit testing system according to an embodiment of the present invention;

[0023] like Figure 1 As shown, braking unit 1 is connected to the DC bus at the output of the third rectifier 100, and braking unit 1 is connected to braking resistor 2. Under the action of the third rectifier 100, the DC bus voltage will rise, thereby forcing braking unit 1 to operate. By adjusting the third rectifier 100, it is possible to test whether the performance and reliability of braking unit 1 meet safety requirements under full load or overload conditions.

[0024] In the above test system, due to the limited output adjustment range of the third rectifier 100, the function of the braking unit 1 in adjusting the DC voltage cannot be tested.

[0025] Based on this, the present invention provides a new braking unit testing system.

[0026] Figure 2 A test system according to an embodiment of the present invention is shown, including a braking unit 1 connected to a braking resistor 2. The test system also includes a first motor 11 and a second motor 12, which are connected by a shaft. The first motor 11 is connected to a first control system 21, and the second motor 12 is connected to a second control system 22. The second control system 22 includes a DC bus adapted to receive feedback energy from the second motor 12. The braking unit 1 is connected to the DC bus of the second control system 22 and is configured to activate a braking mode that dissipates energy through the braking resistor 2 when the DC bus voltage receives the feedback energy and reaches a first preset energy.

[0027] Specifically, the first motor 11 and the second motor 12 can be connected by a coupling. The braking mode is the operating mode of the braking unit 1, where the feedback energy from the DC bus is consumed through the braking resistor 2 connected to it.

[0028] Based on the above embodiments, in one possible implementation, when the braking unit 1 is subjected to a load test, both the first motor 11 and the second motor 12 are in a standby state, and the braking unit 1 is configured to start the braking mode under the action of the second control system 22.

[0029] Specifically, the first motor 11 and the second motor 12 are controlled to be in standby mode, that is, in a state where no speed or torque is generated, for example, by cutting off the power supply. Only the second control system 22 is needed to control the start braking mode, thereby realizing full load or overload testing of the braking unit 1. For example, based on the second control system 22, a certain voltage is output to the DC bus, so that the braking unit 1 reaches the rated voltage, rated current and other rated parameters of the braking unit 1, and it runs for a certain period of time to observe the performance of the braking unit 1 under this working condition.

[0030] Based on the above embodiments, in another possible implementation, the second control system 22 may include a rectifier, and the braking unit 1 is connected to the DC bus at the output of the rectifier. The load test of the braking unit 1 is achieved by adjusting the rectifier.

[0031] According to another embodiment of the present invention, the first motor 11 is configured to operate in speed control mode under the action of the first control system 21, and the second motor 12 is configured to operate in torque control mode under the action of the second control system 22 and generate the feedback energy, wherein the rotation direction of the first motor 11 is opposite to the torque direction of the second motor 12.

[0032] Based on this embodiment, the shaft of the first motor 11 is controlled to generate a rotational speed in the first direction, and the shaft of the second motor 12 generates a torque in the opposite direction, thereby generating feedback energy to the DC bus. When the DC bus voltage rises to a certain value, the braking unit 1 starts to work. At this time, the output PWM duty cycle of the braking unit 1 can be adjusted to adjust the energy consumption of the braking resistor 2. When the energy power consumed by the braking resistor 2 is equal to the feedback energy power of the second motor 12, the voltage of the DC bus reaches a stable state. Based on this, the functional test of the braking unit 1 is realized.

[0033] Based on the above embodiments, in one possible implementation, the feedback energy is achieved by adjusting the torque of the second motor 12. For example, the torque of the second motor 12 can be changed by altering the stator voltage and the power supply frequency.

[0034] Based on the above embodiments, in such Figure 2In another implementation shown, the first control system 21 includes a first rectifier 31 and a first inverter 41 connected in sequence, and the first motor 11 is connected to the output terminal of the first inverter 41. Based on this structure, control of the first motor 11 is achieved, and the braking unit 1 is tested together with the second motor 12.

[0035] Based on the above embodiments, in another implementation, the second control system 22 includes a second rectifier 32 and a second inverter 42 connected in sequence. The second motor 12 is connected to the input terminal of the second inverter 42. The second rectifier 32 does not have an energy feedback function. This enables control of the second motor 12, which, in conjunction with the first motor 11, completes the testing of the braking unit 1. Furthermore, since the second rectifier 32 does not have an energy feedback function, energy feedback is injected into the DC bus to boost the DC voltage.

[0036] In another possible implementation of this utility model, the test system further includes a PWM duty cycle adjustment circuit, which is connected to the braking unit 1 and is adapted to adjust the PWM duty cycle of the braking unit 1.

[0037] Specifically, the circuit structure for adjusting the output PWM duty cycle of braking unit 1 can consist of a signal detection circuit, a control circuit, a drive circuit, and a power switching circuit. The signal detection circuit at least monitors changes in the DC bus voltage. The control circuit (microcontroller MCU or digital signal processor DSP) receives voltage and current feedback signals from the signal detection circuit, incorporates a control algorithm (such as PI control or fuzzy control), performs calculations based on the comparison between the feedback signal and the set value, calculates a suitable PWM duty cycle, and outputs the corresponding PWM control signal. The drive circuit is suitable for isolating and powering the PWM signal to ensure the drive of the power switching circuit. The power switching circuit performs on / off operations based on the PWM signal output by the drive circuit, thereby controlling the output power of braking unit 1. By changing the PWM duty cycle, the conduction time of the power switching device is adjusted, thus regulating the output PWM duty cycle of braking unit 1.

[0038] like Figure 2 In the illustrated embodiment, the braking unit 1 further includes a braking unit 1 input terminal and a braking unit 1 output terminal. The braking unit 1 input terminal and the braking unit 1 output terminal are respectively connected to the positive DC bus and negative DC bus of the DC bus via a protection device 50. Specifically, the protection device 50 can be a fuse, and the circuit is protected based on the setting of the protection device 50.

[0039] In another possible implementation, both the first motor 11 and the second motor 12 are AC motors.

[0040] As can be seen, the test system based on this embodiment of the invention, through a set of motor-support systems, can perform load testing on the braking unit 1 when using only one side of the system. When using both sides of the system simultaneously, the first motor 11 on one side is in speed control mode, and the second motor 12 on the other side is in torque control mode. The rotation direction of the second motor 12 is opposite to that of the first motor 11. In this way, the feedback energy generated by the second motor 12 reaches the DC bus of the second control system 22, causing it to boost voltage, thereby enabling the braking unit 1 to work. At this time, by adjusting the output PWM duty cycle of the braking unit 1 and the feedback energy of the second motor 12, the voltage of the DC bus is observed, thereby determining whether the function of the braking unit 1 is intact. The test system based on this embodiment is more in line with real-world working conditions, making the test results more consistent with actual situations.

[0041] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A brake unit testing system, a brake unit (1) to be tested being connected to a brake resistor (2), characterized in that, The test system further comprises a first motor (11) and a second motor (12), the first motor (11) and the second motor (12) are connected in shaft, the first motor (11) is connected with a first control system (21), the second motor (12) is connected with a second control system (22), the second control system (22) comprises a DC bus, the DC bus is adapted to receive feedback energy of the second motor (12), the brake unit (1) is connected with the DC bus of the second control system (22) and is arranged to start a brake mode of energy dissipation through the brake resistor (2) when the DC bus voltage receives the feedback energy to reach a first preset energy.

2. The brake unit testing system of claim 1, wherein, When the brake unit (1) is subjected to load test, the first motor (11) and the second motor (12) are both in standby state, and the brake unit (1) is arranged to start the brake mode under the action of the second control system (22).

3. The brake unit testing system according to claim 1 or 2, characterized in that, The first motor (11) is arranged to work in a speed control mode under the action of the first control system (21), the second motor (12) is arranged to work in a torque control mode under the action of the second control system (22) and generate the feedback energy, wherein the rotation direction of the first motor (11) is opposite to the torque direction of the second motor (12).

4. The brake unit testing system of claim 3, wherein, The feedback energy is realized based on the adjustment of the torque of the second motor (12).

5. The brake unit testing system of claim 3, wherein, The test system further comprises a PWM duty cycle adjustment circuit connected with the brake unit (1) and adapted to adjust the PWM duty cycle of the brake unit (1).

6. The brake unit testing system of claim 3, wherein, The first control system (21) comprises a first rectifier (31) and a first inverter (41) connected in sequence, and the first motor (11) is connected with the output end of the first inverter (41).

7. The brake unit testing system of claim 6, wherein, The second control system (22) comprises a second rectifier (32) and a second inverter (42) connected in sequence, and the second motor (12) is connected with the input end of the second inverter (42), wherein the second rectifier (32) does not have energy feedback function.

8. The brake unit testing system of claim 1, wherein, The brake unit (1) further comprises a brake unit (1) input end and a brake unit (1) output end, and the brake unit (1) input end and the brake unit (1) output end are respectively connected with the positive DC bus and the negative DC bus of the DC bus through protection devices (50).

9. The brake unit testing system of claim 1, wherein, The first motor (11) and the second motor (12) are both AC motors.

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