Mining electric wheel car permanent magnet driving system counter electromotive force suppression control method and system

Abstract

The application discloses a kind of permanent magnet drive system counter electromotive force suppression control method and system of mine electric wheel car, this method includes: in the running process of mine electric wheel dump truck, real-time detection its running data and state;According to running data and state whether judging electric drive system exists fault;When judging electric drive system appears fault and satisfies counter electromotive force suppression trigger condition, counter electromotive force suppression is carried out: control the all switch tubes of upper bridge arm of inverter module and shut off, control the all switch tubes of lower bridge arm of inverter module and open, or control the all switch tubes of upper bridge arm of inverter module and open, control the all switch tubes of lower bridge arm of inverter module and shut off, let permanent magnet motor be in initiative short-circuit protection state, generate reverse torque control vehicle deceleration, to avoid high counter electromotive force of permanent magnet motor and destroy internal device in middle direct current loop of inverter.The application can carry out counter electromotive force suppression in the moment of inverter serious fault or permanent magnet motor out of control, guarantee normal operation of system.

Description

Technical Field

[0001] This invention mainly relates to the field of mining electric wheel dump truck technology, specifically to a method and system for suppressing and controlling the back electromotive force of a permanent magnet drive system for mining electric wheel trucks. Background Technology

[0002] As China's economy transforms and upgrades, moving towards a more efficient, greener, and lower-carbon direction, major mines have been increasing their investment in mine transportation systems and equipment in recent years. Compared with traditional fuel-powered heavy-duty trucks, which are more expensive and polluting, electric wheel dump trucks can effectively reduce the number of vehicles used and improve work efficiency and safety for the same ore output. As the scale of large open-pit mines at home and abroad continues to expand, the role of electric wheel dump trucks in mining is becoming increasingly prominent.

[0003] Most mining electric wheel dump trucks use diesel engines as their power source. The electric drive system consists of five main parts: diesel engine, generator, drive converter, braking unit, and wheel hub motor. Currently, the mainstream drive motor is generally an asynchronous AC motor, which has the advantages of simple structure and low maintenance. However, it is in a state of low efficiency for a long time during the start-up and low-to-medium speed climbing stages.

[0004] With the emergence of rare-earth neodymium boron and other permanent magnet materials, mining truck manufacturers have gradually begun to choose permanent magnet synchronous motors, which are more efficient, smaller in size, and easier to achieve low speed and high torque. However, the back electromotive force (EMF) of a permanent magnet synchronous motor is proportional to its speed. As the speed of the permanent magnet synchronous motor increases, the back EMF of its windings also increases. When the converter of the electric drive system of the mining electric wheel dump truck is in normal working condition, and the back EMF reaches the voltage limit, the converter controller performs field weakening control to meet the demand for increased motor speed. However, in the case of converter failure or runaway, the back EMF of the permanent magnet synchronous motor poses a challenge to the safety of the electric drive system. Due to the high back EMF of the permanent magnet motor, the safety and reliability of mining electric wheel dump trucks equipped with permanent magnet traction systems are poor when the electric drive system fails, which limits their application. Summary of the Invention

[0005] The technical problem to be solved by this invention is: in view of the problems existing in the prior art, this invention provides a simple, safe and reliable method and system for suppressing back electromotive force in a permanent magnet drive system for mining electric wheel trolleys.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] A method for suppressing and controlling back electromotive force in a permanent magnet drive system for a mining electric wheel trolley includes the following steps:

[0008] During the operation of the mining electric wheel dump truck, the operating data and status of the electric wheel dump truck are monitored in real time;

[0009] The system determines whether there is a fault in the electric drive system based on the operating data and status. When the electric drive system is determined to be faulty and the back EMF suppression trigger condition is met, back EMF suppression is performed: all switches of the upper bridge arm of the inverter module are turned off, and all switches of the lower bridge arm of the inverter module are turned on, or all switches of the upper bridge arm of the inverter module are turned on, and all switches of the lower bridge arm of the inverter module are turned off, so that the permanent magnet motor is in an active short-circuit protection state, generating reverse torque to control the vehicle deceleration, so as to avoid the high back EMF of the permanent magnet motor being applied to the intermediate DC circuit of the converter and damaging the internal components.

[0010] As a further improvement to the above technical solution:

[0011] After suppressing the back EMF, the speed of the permanent magnet motor and the intermediate DC voltage data of the converter are monitored in real time to determine whether the electric drive system meets the restart conditions. If the restart conditions are met, the system is allowed to restart.

[0012] The restart conditions include a re-start formula. If the re-start formula is true, the system is allowed to restart; otherwise, back EMF suppression is maintained. Specifically, the re-start formula is nK. dc Where n is the motor speed in r / min; Udc is the DC circuit voltage of the converter; and K is the re-energization factor at the current motor speed.

[0013] If the electric drive system remains in a state of back electromotive force suppression for an extended period or fails to restart after re-starting, it indicates that the vehicle is out of control. In this case, mechanical braking will be applied to decelerate and stop the vehicle, and a corresponding alarm will be triggered.

[0014] The operating data and status are compared with the data in the preset fault database to determine the fault level and type. Then, it is determined whether the back EMF suppression triggering condition is met based on the fault level and type. When the fault level and type is a severe fault on the motor side, the back EMF suppression triggering condition is met.

[0015] When the fault level and type are minor or moderate, the vehicle continues to operate or operates with reduced power.

[0016] The serious faults on the motor side include inverter module IGBT failure or motor position sensor damage causing motor loss of control.

[0017] This invention also discloses a back EMF suppression control system for a permanent magnet drive system of a mining electric wheel trolley, comprising:

[0018] The first module is used to monitor the operating data and status of the electric wheel dump truck in real time during its operation.

[0019] ​The second module is used to determine whether there is a fault in the electric drive system based on the operating data and status. When it is determined that there is a fault in the electric drive system and the back EMF suppression trigger condition is met, back EMF suppression is performed: all switches of the upper bridge arm of the inverter module are turned off, and all switches of the lower bridge arm of the inverter module are turned on, or all switches of the upper bridge arm of the inverter module are turned on and all switches of the lower bridge arm of the inverter module are turned off, so that the permanent magnet motor is in an active short-circuit protection state, generating reverse torque to control the vehicle deceleration, so as to avoid the high back EMF of the permanent magnet motor being applied to the intermediate DC circuit of the converter and damaging the internal components.

[0020] The present invention further discloses a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when run by a processor, executes the steps of the back electromotive force suppression control method for a permanent magnet drive system for a mining electric wheel trolley as described above.

[0021] The present invention also discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and the computer program, when run by the processor, executes the steps of the back electromotive force suppression control method for the permanent magnet drive system of a mining electric wheel trolley as described above.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] The back EMF suppression control method for the permanent magnet drive system of the mining electric wheel dump truck of the present invention protects the electric drive system from damage by suppressing back EMF at the moment of serious converter failure or permanent magnet motor runaway. Secondly, through a reactivation control strategy after system failure, the real-time state of the system after the failure is judged, and the converter is controlled to be reactivated in time to ensure normal system operation. In addition, the back EMF suppression control method of the present invention can effectively suppress the high back EMF of the permanent magnet motor at the moment of electric drive system failure, and also has a certain electric braking force, improving the safety performance of the whole vehicle and avoiding frequent use of the mechanical braking system. Attached Figure Description

[0024] Figure 1 This is a flowchart of the method of the present invention in an embodiment.

[0025] Figure 2 This is a block diagram of the driving system of the present invention in an embodiment.

[0026] Legend: 1. Main generator; 2. Rectifier module; 3. Inverter module; 4. Permanent magnet motor; 5. Braking unit. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 2As shown, the permanent magnet drive system for a mining electric wheel dump truck corresponding to this embodiment of the invention includes a main generator 1, a rectifier module 2, a permanent magnet motor 4, and an inverter module 3. The main generator 1 is connected to the permanent magnet motor 4 via the rectifier module 2 and the inverter module 3 in sequence. The main generator 1 is used to generate three-phase alternating current (AC). The rectifier module 2 is used for three-phase uncontrolled rectification to convert the AC to DC. The inverter module 3 is used to convert the rectified DC into AC with adjustable frequency and amplitude to drive the motor. The permanent magnet motor 4 is used to drive the vehicle. It also includes a braking unit 5, used to absorb braking energy or suppress the back electromotive force of the permanent magnet motor 4 in fault conditions. The braking unit 5 includes a chopper resistor. Of course, in other embodiments, energy storage components such as batteries can be used instead of the chopper resistor.

[0029] like Figure 1 As shown, the back EMF suppression control method for the permanent magnet drive system of a mining electric wheel trolley according to an embodiment of the present invention includes the following steps:

[0030] During the operation of the mining electric wheel dump truck, the operating data and status of the electric wheel dump truck are monitored in real time. The operating data includes the speed of the permanent magnet motor, the current of the permanent magnet motor, and the DC bus voltage at the back end of the rectifier module. The status includes the real-time fault status of the electric drive system.

[0031] The system determines whether there is a fault in the electric drive system based on the operating data and status. When the electric drive system is determined to be faulty and the back EMF suppression trigger condition is met, back EMF suppression is performed: the three transistors of the upper bridge arm of the inverter module are turned off, and the three transistors of the lower bridge arm of the inverter module are turned on, or the three transistors of the upper bridge arm of the inverter module are turned on, and the three transistors of the lower bridge arm of the inverter module are turned off, so that the permanent magnet motor 4 is in an active short-circuit protection state, generating reverse torque to control the vehicle deceleration, so as to avoid the high back EMF of the permanent magnet motor 4 being applied to the intermediate DC circuit of the converter and damaging the internal components.

[0032] Furthermore, after back EMF suppression, the speed of the permanent magnet motor 4 and the intermediate DC voltage data of the converter are monitored in real time to determine whether the electric drive system meets the restart conditions. If the restart conditions are met, the system is allowed to restart. Specifically, the restart conditions include a re-start formula. If the re-start formula is valid, the system is allowed to restart; otherwise, back EMF suppression is maintained. The re-start formula is specifically nK. dc Where n is the motor speed in r / min; Udc is the DC circuit voltage of the converter; K is the re-energization coefficient at the current motor speed, K = Un * 1.414 / n / 0.85, where Un is the effective value of the no-load back electromotive force at the motor speed point.

[0033] ​Furthermore, if the electric drive system remains in a state of back electromotive force suppression for an extended period or fails to restart after re-starting, it indicates that the vehicle is out of control. The driver will be alerted on the cab display unit that the electric drive system is malfunctioning and that mechanical braking is required to slow down and stop the vehicle.

[0034] In one specific embodiment, the operating data and status are compared with data in a preset fault database to determine the fault level and type. Then, based on the fault level and type, it is determined whether the back EMF suppression triggering condition is met. When the fault level and type is a severe motor-side fault, the back EMF suppression triggering condition is met, and the pulses of inverter module 3 need to be blocked to prevent further fault escalation. When the fault level and type are minor or moderate faults, the vehicle continues to operate or operates with reduced power. Specifically, severe motor-side faults include inverter module 3 IGBT failure or motor position sensor damage causing motor runaway.

[0035] The back EMF suppression control method of the permanent magnet drive system of the mining electric wheel dump truck of the present invention protects the electric drive system from damage by suppressing back EMF at the moment of serious converter failure or loss of control of permanent magnet motor 4. Secondly, through the reactivation control strategy after system failure, the real-time state of the system after failure is judged and the converter is controlled to be reactivated in time to ensure normal system operation. In addition, the back EMF suppression control method of the present invention can effectively suppress the high back EMF of permanent magnet motor 4 at the moment of electric drive system failure, and also has a certain electric braking force, improving the safety performance of the whole vehicle and avoiding frequent use of mechanical braking system.

[0036] This invention also discloses a back EMF suppression control system for a permanent magnet drive system of a mining electric wheel trolley, comprising:

[0037] The first module is used to monitor the operating data and status of the electric wheel dump truck in real time during its operation.

[0038] The second module is used to determine whether there is a fault in the electric drive system based on the operating data and status. When it is determined that there is a fault in the electric drive system and the back EMF suppression trigger condition is met, back EMF suppression is performed: the three transistors of the upper bridge arm of the inverter module are turned off, and the three transistors of the lower bridge arm of the inverter module are turned on, or the three transistors of the upper bridge arm of the inverter module are turned on, and the three transistors of the lower bridge arm of the inverter module are turned off, so that the permanent magnet motor 4 is in an active short-circuit protection state, generating reverse torque to control the vehicle deceleration, so as to avoid the high back EMF of the permanent magnet motor 4 being applied to the intermediate DC circuit of the converter and damaging the internal components.

[0039] The control system of the present invention corresponds to the control method described above and also has the advantages described in the control method.

[0040] This invention further discloses a computer-readable storage medium storing a computer program. When executed by a processor, the computer program performs the steps of the back EMF suppression control method for a permanent magnet drive system of a mining electric wheel trolley as described above. This invention also discloses a computer device including a memory and a processor. The memory stores a computer program, which, when executed by a processor, performs the steps of the back EMF suppression control method for a permanent magnet drive system of a mining electric wheel trolley as described above. This invention can implement all or part of the processes in the methods of the above embodiments, or it can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. Memory can be used to store computer programs and / or modules. The processor performs various functions by running or executing the computer programs and / or modules stored in the memory, and by accessing data stored in the memory. Memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital cards (SD cards), flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0041] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for suppressing and controlling the back electromotive force of a permanent magnet drive system for a mining electric wheel trolley, characterized in that, Including the following steps: During the operation of the mining electric wheel dump truck, the operating data and status of the electric wheel dump truck are monitored in real time; The system is judged to have a fault based on the operating data and status. When the electric drive system is judged to have a fault and the back EMF suppression trigger condition is met, back EMF suppression is performed: all switches of the upper bridge arm of the inverter module are turned off, and all switches of the lower bridge arm of the inverter module are turned on, or all switches of the upper bridge arm of the inverter module are turned on and all switches of the lower bridge arm of the inverter module are turned off, so that the permanent magnet motor (4) is in the active short circuit protection state, and reverse torque is generated to control the vehicle to decelerate, so as to avoid the high back EMF of the permanent magnet motor (4) being applied to the intermediate DC circuit of the converter and damaging the internal components. After the back EMF is suppressed, the speed of the permanent magnet motor (4) and the DC voltage data of the converter are detected in real time to determine whether the electric drive system meets the restart conditions. If the restart conditions are met, the system is allowed to restart. The restart conditions include a re-start formula. If the re-start formula is true, the system is allowed to restart; otherwise, back EMF suppression is maintained. The re-start formula is specifically as follows: Where n is the motor speed in r / min; Udc is the DC circuit voltage of the converter; K is the re-energization coefficient at the current motor speed, K=Un*1.414 / n / 0.85, where Un is the effective value of the no-load back electromotive force at the motor speed point.

2. The back electromotive force suppression control method for the permanent magnet drive system of a mining electric wheel trolley according to claim 1, characterized in that, If the electric drive system remains in a state of back electromotive force suppression for an extended period or fails to restart after re-starting, it indicates that the vehicle is out of control. In this case, mechanical braking will be applied to decelerate and stop the vehicle, and a corresponding alarm will be triggered.

3. The back electromotive force suppression control method for a permanent magnet drive system of a mining electric wheel trolley according to any one of claims 1 to 2, characterized in that, The operating data and status are compared with the data in the preset fault database to determine the fault level and type. Then, it is determined whether the back EMF suppression triggering condition is met based on the fault level and type. When the fault level and type is a severe fault on the motor side, the back EMF suppression triggering condition is met.

4. The back EMF suppression control method for the permanent magnet drive system of a mining electric wheel trolley according to claim 3, characterized in that, When the fault level and type are minor or moderate, the vehicle continues to operate or operates with reduced power.

5. The back electromotive force suppression control method for the permanent magnet drive system of a mining electric wheel trolley according to claim 3, characterized in that, The serious faults on the motor side include inverter module (3) IGBT failure or motor position sensor damage causing motor loss of control.

6. A back EMF suppression control system for a permanent magnet drive system of a mining electric wheel trolley, used to execute the steps of the back EMF suppression control method for a permanent magnet drive system of a mining electric wheel trolley as described in any one of claims 1 to 5, characterized in that, include: The first module is used to monitor the operating data and status of the electric wheel dump truck in real time during its operation. The second module is used to determine whether there is a fault in the electric drive system based on the operating data and status. When it is determined that there is a fault in the electric drive system and the back EMF suppression trigger condition is met, back EMF suppression is performed: control all the switches of the upper bridge arm of the inverter module to turn off, control all the switches of the lower bridge arm of the inverter module to turn on, or control all the switches of the upper bridge arm of the inverter module to turn on, control all the switches of the lower bridge arm of the inverter module to turn off, so that the permanent magnet motor (4) is in the active short circuit protection state, and generates reverse torque to control the vehicle to decelerate, so as to avoid the high back EMF of the permanent magnet motor (4) being applied to the intermediate DC circuit of the converter and damaging the internal components.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run by the processor, it executes the steps of the back EMF suppression control method for the permanent magnet drive system of a mining electric wheel trolley as described in any one of claims 1 to 5.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the computer program is run by the processor, it executes the steps of the back EMF suppression control method for the permanent magnet drive system of a mining electric wheel trolley as described in any one of claims 1 to 5.

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