A control method for a multi-drive master-slave device of a positioning vehicle

Abstract

The present invention discloses a method for controlling a multi-drive master-slave device for a positioning vehicle. The method connects multiple frequency converters to a programmable logic controller (PLC) via a first bus, and connects the multiple frequency converters to each other via a second bus. The PLC sets any frequency converter as a master frequency converter and the remaining frequency converters as slave frequency converters via the first bus. During the control process, all frequency converters use a common ramp function generator (RGF) of the master frequency converter to calculate an RFG output set value. A Droop softening function is used for master-slave load control. The integral torque set value of the speed regulator of the master frequency converter is adjusted using the integral torque set value of the speed regulator of the slave frequency converter to achieve dynamic load balancing of the master-slave device. The present invention not only ensures speed synchronization of the multi-drive motors of the positioning vehicle, but also achieves load balancing between the motors, thereby effectively reducing torque fluctuations, improving the control quality of the multi-drive master-slave device, and ensuring stable operation of the tipping machine system.

Description

Technical Field

[0001] The invention relates to a control method for a positioning vehicle multi-transmission master-slave device applicable to a port specialized coal terminal dumper system, belonging to the field of control technology. Background Art

[0002] The car dumper system at the port's specialized coal terminal requires a positioning vehicle to drive 105 heavy vehicles during production operations. Due to process requirements and limited inverter capacity, multiple motors are required to jointly drive the positioning vehicle. The positioning vehicle's movement is achieved by 12 motors, each connected to its own reduction gearbox. Each motor's load cannot be uniform, and if this load variation is not eliminated, it will damage the positioning vehicle's mechanical transmission. To address this issue, each drive motor must maintain the same operating speed and evenly distribute torque. Therefore, a multi-drive master-slave control method for the positioning vehicle is required.

[0003] In existing multi-drive master-slave control systems for positioning vehicles, the master motor typically uses speed control and the slave motors use torque control. The master motor transmits torque commands to the slave motors, which then use the received torque information as commands for their own torque loops, thereby controlling the master-slave load balance between the two motors. This control method relies entirely on the master motor's signals for torque distribution between the master and slave motors, forcing the slave motors to passively follow. Torque control for the slave motors is open-loop in the control system. Because the positioning vehicle drive structure of the tipping vehicle system is a cross between rigid and flexible connections, and because the positioning vehicle is driven by as many as 12 motors, this single-master, multi-slave master-slave arrangement suffers from poor master-slave control coordination and significant torque fluctuations.

[0004] In the existing positioning vehicle multi-drive master-slave device control system, if the master inverter fails, the slave inverter will not be able to receive the given signal from the master inverter, and the entire drive control system will not operate normally, which has a significant impact on the production system. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of the existing technology and provide a method for controlling a multi-transmission master-slave device of a positioning vehicle to improve the control quality of the multi-transmission master-slave device and ensure the stable operation of the tipping machine system.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for controlling a multi-drive master-slave device of a positioning vehicle is disclosed. The method connects multiple frequency converters connected to multiple motors of the positioning vehicle to a programmable logic controller (PLC) via a first bus, and connects the multiple frequency converters to each other via a second bus. The PLC sets any frequency converter as a master frequency converter via the first bus, disables the bypass function of the master frequency converter, and enables the RFG function. The PLC sets the remaining frequency converters as slave frequency converters, disables the RFG function of the slave frequency converters, and enables the bypass function. During the control process, all frequency converters use a common ramp function generator of the master frequency converter to calculate an RFG output setting value. A Droop softening function is used in master-slave load control. The integral setting value of the slave frequency converter speed regulator is adjusted using the torque setting value of the integral link of the master frequency converter speed regulator, thereby achieving dynamic load balancing of the master-slave device.

[0008] The above positioning vehicle multi-transmission master-slave device control method comprises the following steps:

[0009] a. Get the speed given value: The main inverter receives the speed given value sent by the PLC through the first bus;

[0010] b. Obtain the output setting value of the ramp function generator RFG: The speed reference value obtained by the main inverter is calculated by the ramp function generator to obtain the output setting value of the RFG;

[0011] c. RFG output setting value transmission: The master inverter transmits the RFG output setting value to each slave inverter through the second bus;

[0012] d. Obtaining the softening speed reduction value: The integral link torque setting value output by the speed regulator of each inverter is adjusted by the softening function to obtain the softening speed reduction value;

[0013] e. Obtain the motor's rotational speed feedback value: Calculate the speed feedback value based on the pulse signal output by the incremental encoder installed at the rear of the motor;

[0014] f. Obtaining the motor torque and current feedback value: Detecting the motor's output three-phase current and obtaining the torque and current feedback value through coordinate transformation;

[0015] g. Obtaining the motor speed control value: The RFG output set value of the main inverter is compared with the softening speed reduction value of each inverter, and then after speed limiting, it is compared with the speed feedback value of the motor to obtain the speed control value of each motor;

[0016] f. Obtain the torque setting value of the integral link of the speed regulator: The torque setting value of the integral link output by the speed regulator in the main inverter is used as the integral setting value of the speed regulator of each inverter; the speed regulator of each inverter calculates the torque setting value of the integral link based on the motor speed control value and the integral setting value;

[0017] g. Obtaining the motor current control value: Compare the torque current set value output by the speed regulator with the motor torque current feedback value, and obtain the motor current control value after the PI control of the current regulator;

[0018] h. Pulse signal controls each motor: The current control quantity is vector controlled to obtain the AC voltage setting value of each inverter, and a pulse signal is sent through PMW modulation to drive the IGBT power device to control each motor.

[0019] The above-mentioned positioning vehicle multi-transmission master-slave device control method, when a fault occurs in the slave inverter, the fault information is sent to the PLC through the first bus, and the PLC will shut it down and no longer participate in drive control; when a fault occurs in the master inverter, the fault information is sent to the PLC through the first bus, and the PLC switches a slave inverter to the master inverter. The original master inverter is switched to the slave inverter and then shuts down and no longer participates in drive control.

[0020] In the above positioning vehicle multi-drive master-slave device control method, the first bus is a PROFIBUS-DP bus, and the second bus is a SINAMICS-Link bus.

[0021] The present invention adopts a method of sharing a ramp function generator of a master inverter to realize synchronous transmission of data; adopts a droop softening function in master-slave load control to realize effective load distribution; adopts a method of adjusting the integral setting value of the speed regulator of the slave inverter by the torque setting value of the integral link of the speed regulator of the master inverter to realize dynamic load balancing of the master and slave devices, thereby ensuring speed synchronization of the multi-drive motors of the positioning vehicle and realizing load balancing between the motors, thereby effectively reducing the torque fluctuation amplitude, improving the control quality of the multi-drive master-slave device, and ensuring the stable operation of the tipping machine system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 A schematic diagram of the bus control composition of a positioning vehicle multi-transmission master-slave device control system provided by an embodiment of the present invention;

[0024] Figure 2 A schematic structural diagram of a multi-transmission master-slave device control system for a positioning vehicle provided by an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of a fault handling process for a multi-transmission master-slave device of a positioning vehicle provided by an embodiment of the present invention.

[0026] The reference numerals in the figure are: PLC, programmable controller, B1 to Bn, first to nth frequency converters, M1 to Mn, first to nth motors, and Z, load. DETAILED DESCRIPTION

[0027] The present invention enables multiple motors to operate in a synchronized state by performing master-slave synchronous control on the frequency converters. In the control, all slave frequency converters share the master frequency converter's ramp function generator to calculate the RFG output set value. This value is transmitted via SINAMICS-Link communication, enabling isochronous data transmission and improving system synchronization. A Droop softening function is used in master-slave load control to ensure that the speed set value decreases proportionally as the load torque increases, achieving effective load distribution. Simultaneously, in master-slave load balancing control, the integral set value of the slave frequency converter's speed regulator is adjusted using the integral set value of the master frequency converter's speed regulator using the integral set value of the master frequency converter's speed regulator, achieving dynamic load balancing between the master and slave devices. When the master frequency converter fails, the PLC automatically switches the frequency converter master-slave relationship and disconnects the faulty frequency converter, rapidly restoring the entire system. The present invention ensures speed synchronization of the positioning vehicle's multiple drive motors while achieving load balancing between the motors, thereby improving system reliability.

[0028] like Figure 1 and Figure 2 As shown, the positioning vehicle multi-drive master-slave control system of the present invention includes a programmable logic controller (PLC) and multiple frequency converters. The multiple frequency converters are connected via the SINAMICS-Link bus, and the PLC is connected to each frequency converter via the PROFIBUS-DP bus. During operation, the PLC sends control commands via PROFIBUS-DP communication to set any frequency converter as the master frequency converter, disabling its bypass function and enabling the RFG. The remaining frequency converters are set as slave frequency converters, disabling their RFG functions and enabling their bypass functions. Data is exchanged between the master and slave frequency converters via the SINAMICS-Link bus. Specifically, the master frequency converter transmits the RFG output setpoint r1150 and the integral link torque setpoint r1482 to the slave frequency converters via SINAMICS-Link communication. The slave frequency converters receive the RFG output setpoint r1150 and the integral link torque setpoint r1482 from the master frequency converter. In any case, only one frequency converter can serve as the master frequency converter.

[0029] Assuming that the PLC sets the first inverter B1 as the master inverter and the second inverter B2 to the nth inverter Bn as the slave inverters, the PLC issues a control command to disable the inverter bypass function of the first inverter B1 and enable the RFG. The first inverter B1 sends the RFG output setting value r1150 and the integral link torque setting value r1482 to the slave inverter; the PLC issues a control command to disable the RFG of the second inverter B2 to the nth inverter Bn and enable the bypass function. The second inverter B2 to the nth inverter Bn receive the RFG output setting value r1150 and the integral link torque setting value r1482 from the first inverter B1. If the first inverter B1 fails, the first inverter B1 sends the fault information to the PLC via PROFIBUS-DP. After logical judgment, the PLC switches the second inverter B2 to the master inverter and simultaneously issues a control command to switch the first inverter B1 to the slave inverter and stop running, so that it no longer participates in drive control. The PLC issues a control command to disable the bypass function of the second inverter B2 and enable the RFG. The second inverter B2 sends the RFG output set value r1150 and the integral link torque set value r1482 to the third inverter B3 to the nth inverter Bn. The PLC also issues a control command to disable the RFG and enable the bypass function of the third inverter B3 to the nth inverter Bn. The third inverter B3 to the nth inverter Bn receive the RFG output set value r1150 and the integral link torque set value r1482 from the second inverter B2.

[0030] In the present invention, the structure and connection of the master inverter and the slave inverter are the same. The inverter adopts SIEMENSS120 inverter and is equipped with CU320-2DP control unit. The master inverter is the master motor inverter, and the slave inverter is the slave motor inverter. The control mode of the master and slave inverters both adopts the speed vector control mode with speed encoder feedback. The master-slave device control is controlled between the master and slave inverters.

[0031] The positioning vehicle multi-transmission master-slave device control method includes the following steps:

[0032] Step S1, obtaining a speed reference value: the main inverter receives a speed reference value sent by the PLC via the PROFIBUS-DP communication network;

[0033] Step S2, obtaining the ramp function generator RFG output setting value: the speed reference value obtained by the main frequency converter is subjected to parameter calculation by the ramp function generator, and the obtained speed output value is the RFG output setting value r1150;

[0034] Step S3, RFG output set value transmission: The master inverter transmits the RFG output set value r1150 to the slave inverter via SINAMICS-Link communication;

[0035] Step S4, obtaining a softening speed reduction value: the integral link torque setting value r1482 output by the speed regulator of each inverter is adjusted by the softening function to obtain a softening speed reduction value r1490;

[0036] Step S5, obtaining the rotation speed feedback value of the motor: calculating the speed feedback value r1445 according to the pulse signal output by the incremental encoder installed at the rear of the motor;

[0037] Step S6, obtaining the motor torque current feedback value: detecting the output three-phase current of the motor, and obtaining the torque current feedback value r30 through coordinate transformation;

[0038] Step S7, obtaining the motor speed control value: the RFG output setting value of the main inverter is compared with the softening speed reduction value of each inverter, and then after speed limiting, it is compared with the speed feedback value of the motor to obtain the speed control value r64 of each motor;

[0039] Step S8, obtaining the speed regulator integral link torque setting value: the integral link torque setting value r1482 output by the speed regulator in the master inverter is used as the integral link torque setting value P1478 of the speed regulator of each inverter; the integral link torque setting value P1478 is transmitted via SINAMICS-Link communication between the master and slave inverters; the speed regulator of each inverter calculates the integral link torque setting value r1482 based on the motor speed control value r64 and the integral link torque setting value P1478;

[0040] Step S9, obtaining the motor current control value: comparing the torque current set value output by the speed regulator with the motor torque current feedback value r30, and obtaining the motor current control value after PI control of the current regulator;

[0041] Step S10: Pulse signals are used to control each motor: the AC voltage setting value of each inverter is obtained through vector control, and pulse signals are sent through PMW modulation to drive IGBT power devices to control each motor;

[0042] Step S11, master-slave switching control: Master-slave control switching can be performed between the master and slave inverters. The master inverter can be switched to the slave inverter, and the slave inverter can be switched to the master inverter for control. When the master inverter fails, the system switches one of the slave inverters to the master inverter, and the original master inverter is switched to the slave inverter to exit operation and no longer participate in drive control. When the slave inverter fails, the slave inverter will exit operation and no longer participate in drive control.

[0043] In the embodiment of the present invention, the speed setting values of the master and slave frequency converters are calculated using the same ramp function generator, and the calculated value is the RFG output setting value. The ramp function generator is the ramp function generator of the master frequency converter.

[0044] In the embodiment of the present invention, the master inverter transmits the RFG output setting value to each slave inverter via SINAMICS-Link communication, so that the master and slave inverters have the same speed setting;

[0045] In the embodiment of the present invention, the data transmission time of the SINAMICS-Link communication between the master inverter and the slave inverter can reach 1000μs, thereby greatly shortening the bus execution cycle, eliminating the influence of the synchronization of the master-slave control, and improving the master-slave control accuracy;

[0046] In the embodiment of the present invention, both the master and slave inverters employ a Droop softening function. This function applies a speed reduction value, calculated after softening and speed conversion, to the integral torque setpoint output by the inverter speed regulator. This value is then added to the speed reference. This function adjusts the speed of the individual motors accordingly, limiting potential mechanical torque differences and reducing the drive load when torque is excessive. Proper parameter settings can soften the mechanical connection and control slip. This ensures that as load torque increases, the speed setpoint decreases proportionally, achieving effective load distribution.

[0047] In this embodiment of the present invention, the master inverter transmits the torque setting value r1482 of the integral link output of its speed regulator to the integral setting value P1478 of the speed regulator of each slave inverter via SINAMICS-Link communication. This ensures that when the load torque changes, the master inverter can dynamically distribute the torque to the slave inverters, thereby achieving load balancing control of the master and slave devices.

[0048] In the embodiment of the present invention, both the master inverter and the slave inverter adopt dual-loop control. After the inverter passes through the speed outer loop control, the output torque current set value is used as the set value of the current inner loop;

[0049] The method for correcting a fault in a multi-drive master-slave device of a positioning vehicle according to an embodiment of the present invention includes a master-slave switching control function, wherein a master-slave control switching can be performed between the master and slave frequency converters, wherein the master frequency converter can be switched to the slave frequency converter, and the slave frequency converter can be switched to the master frequency converter;

[0050] When a slave inverter fails, the slave inverter sends the fault information to the PLC via PROFIBUS-DP. After logical judgment, the PLC will exit the faulty slave inverter and no longer participate in drive control. The faulty inverter can be powered off for repair or replacement without affecting the operation of other equipment, ensuring that the system can still operate stably after the power is reduced due to the fault.

[0051] like Figure 3As shown, when the first frequency converter B1 is the master frequency converter, if the first frequency converter B1 fails, the master frequency converter sends the fault information to the PLC via PROFIBUS-DP. After logical judgment, the PLC switches one of the slave frequency converters to the master frequency converter. The original master frequency converter is switched to the slave frequency converter and exits operation and no longer participates in drive control. The faulty frequency converter can be powered off for repair or replacement without affecting the operation of other equipment. According to the positioning vehicle multi-transmission master-slave device control method of the present invention, any normally operating frequency converter can be operated as a master frequency converter or a slave frequency converter. Under normal circumstances, the master-slave relationship of the frequency converter can also be manually switched through the operation screen, and the master-slave switching function can be regularly tested, thereby improving the reliability of the positioning vehicle multi-transmission master-slave device control system operation, ensuring that the system can still operate stably after the power is reduced due to a fault, and at the same time, the faulty frequency converter can be repaired or replaced without affecting the normal operation of the system, thereby improving the flexibility of the system.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling a multi-transmission master-slave device of a positioning vehicle, characterized in that: The method connects multiple frequency converters connected to multiple motors of a positioning vehicle to a PLC via a first bus, and connects the multiple frequency converters to each other via a second bus. The PLC sets any frequency converter as a master frequency converter via the first bus, disables the bypass function of the master frequency converter, and enables the RFG. The PLC sets the remaining frequency converters as slave frequency converters, disables the RFG of the slave frequency converters, and enables the bypass function. During the control process, all frequency converters use a common ramp function generator of the master frequency converter to calculate an RFG output setting value. A Droop softening function is used in master-slave load control. At the same time, a method is used to adjust the integral setting value of the slave frequency converter speed regulator using the torque setting value of the integral link of the master frequency converter speed regulator to achieve dynamic load balancing of the master-slave device. The first bus is a PROFIBUS-DP bus, and the second bus is a SINAMICS-Link bus; The master inverter transmits the RFG output setpoint r1150 and the integral torque setpoint r1482 to the slave inverter via SINAMICS-Link communication. The method comprises the following steps: a. Get the speed given value: The main inverter receives the speed given value sent by the PLC through the first bus; b. Obtain the output setting value of the ramp function generator RFG: The speed reference value obtained by the main inverter is calculated by the ramp function generator to obtain the output setting value of the RFG; c. RFG output setting value transmission: The master inverter transmits the RFG output setting value to each slave inverter through the second bus; d. Obtaining the softening speed reduction value: The integral link torque setting value output by each inverter speed regulator is adjusted by the softening function to obtain the softening speed reduction value; e. Obtain the motor's rotational speed feedback value: Calculate the speed feedback value based on the pulse signal output by the incremental encoder installed at the rear of the motor; f. Obtaining the motor torque and current feedback value: Detecting the motor's output three-phase current and obtaining the torque and current feedback value through coordinate transformation; g. Obtaining the motor speed control value: The RFG output set value of the main inverter is compared with the softening speed reduction value of each inverter, and then compared with the motor speed feedback value after speed limiting to obtain the speed control value of each motor; f. Obtaining the torque setting value of the integral link of the speed regulator: The torque setting value of the integral link output by the speed regulator in the master inverter is used as the integral setting value of the speed regulator of each inverter; the speed regulator of each inverter calculates the torque setting value of the integral link based on the motor speed control value and the integral setting value; g. Obtaining the motor current control value: Compare the torque current setpoint output by the speed regulator with the motor torque current feedback value, and obtain the motor current control value through PI control of the current regulator; h. Pulse signals control each motor: The current control quantity is vector controlled to obtain the AC voltage setting value of each inverter, and pulse signals are sent through PMW modulation to drive IGBT power devices to control each motor.

2. A positioning vehicle multi-transmission master-slave device control method according to claim 1, characterized in that: When a slave inverter fails, the fault information is sent to the PLC through the first bus, and the PLC will shut it down and no longer participate in drive control; when a master inverter fails, the fault information is sent to the PLC through the first bus, and the PLC will switch a slave inverter to the master inverter. The original master inverter will shut down and no longer participate in drive control after being switched to the slave inverter.

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