Rail transit vehicle traction system electrocorrosion intelligent management system and algorithm thereof

Abstract

The invention discloses a rail transit vehicle traction system electrocorrosion intelligent management system and an algorithm thereof. The system comprises a hardware equipment part and a software control part. The hardware equipment part comprises a controller, a data storage and transmission part, a power supply circuit, a display terminal and an acquisition terminal; the software control part is completed by a controller, and logic control and an algorithm are built in the controller; the beneficial effects of the invention are that: starting from the generation root of the bearing electro-corrosion problem, the reduction of the common-mode voltage of the bearing outer ring is taken as the target, the discharge probability of the shaft voltage to the bearing is reduced, and the innovation is that the common-mode dynamic voltage, the shaft current, the motor speed and the motor temperature of the traction motor side are monitored in real time and fed back to the controller in real time; the'sparse 'of the traditional method is changed into'drop' from the source, a'real-time 'feedback acquisition device of'common-mode dynamic voltage, current, speed and temperature' of the traction motor bearing is designed, and dynamic high-speed acquisition of variables such as current, voltage, speed and temperature of a motor shaft is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit, and specifically relates to an intelligent management system and algorithm for electric corrosion of a rail transit vehicle traction system. Background Art

[0002] 1. The traction systems of rail transit vehicles all adopt variable voltage variable frequency traction inverters (referred to as VVVF for short), which are controlled and managed by traction control units (referred to as TCU for short) to drive traction motors. Since VVVF is generally a voltage-type two-point three-phase three-arm inverter, pulse width modulation (referred to as PWM for short) control technology is adopted. Due to the high-frequency switching of the PWM control power device (IGBT), the neutral point voltage of the three-phase output voltage of VVVF with respect to the ground is not zero at the same moment, that is, the neutral point shifts. The principle waveform is as Figure 6 shown. Where U u (t), U v (t), U w (t) are the U-phase, V-phase, and W-phase voltages output by VVVF respectively, and U cm (t) is the sum of the three-phase voltages output by VVVF, that is, the common mode voltage.

[0003] The neutral point shift causes an inevitable common mode voltage U cm to be generated between the motor phase winding and the reference ground, and the common mode voltage finally acts on the motor bearing. The specific principle is as follows: The outer ring of the motor bearing is fixed on the motor housing and is equipotential with the motor housing. The inner ring of the bearing is installed on the motor shaft by interference fit and is equipotential with the shaft. There are rollers and grease filling between the inner and outer rings. The outer ring and the inner ring of the bearing are equivalent to the two plates of a capacitor, and the common mode voltage causes an electric potential difference between the outer ring of the bearing and the rollers and the inner ring. This makes it inevitable for VVVF to generate a common mode voltage.

[0004] The common mode voltage will cause shaft voltage and shaft current of the traction motor, and further cause problems such as insulation breakdown of the traction motor bearing and roller breakage (also known as electric corrosion). The generation mechanism is as follows: The radial clearance of the traction motor bearing is generally (0.12 - 0.16) mm, and it is in a dynamically changing state in practice. The clearance is related to vehicle load, bearing rolling speed, etc. When the outer ring, rollers, and inner ring are in a certain position, resulting in a small electrical clearance, coupled with an excessive shaft voltage, tip discharge will occur. This will further cause problems such as insulation breakdown of the traction motor bearing grease and roller breakage (also known as electric corrosion). The discharge current will cause electric corrosion to the bearing. The relationship between the bearing common mode voltage and the electric corrosion path is as Figure 7 shown, and the typical bearing damage caused by electric corrosion is as Figure 8 shown.

[0005] Ultimately, it leads to the failure of the traction motor bearings, triggering serious faults in the traction motor, accompanied by phenomena such as motor locking, smoking, and severe vehicle shaking, which has a great impact on operation safety. Moreover, the problem of electro-corrosion in the traction system is extremely common.

[0006] 2. After the electro-corrosion of the traction motor bearings is caused by the vehicle traction system, it leads to the early disassembly of the traction motor and replacement of the bearings in the vehicle's low-level maintenance procedures. The maintenance cycle of a single traction motor (excluding the transportation cycle) is about 3 days, and the maintenance cost is about 20,000 yuan (including the replacement of 1 set of bearings). This greatly increases the maintenance costs in many aspects such as manpower, spare parts, economy, and detention downtime for the rail transit vehicle maintenance units and operation companies.

[0007] Currently, there are no effective measures to solve the electro-corrosion problem of the rail transit vehicle traction system, especially for the vehicles on existing old lines. Due to the very narrow space between the shaft extension end of the vehicle traction motor and the coupling, and the high-speed rotation of the traction motor shaft and the coupling together, there are difficulties in measuring the shaft current of the traction motor, high risks, and the inability to quantitatively evaluate. The electro-corrosion problem of the traction system has become a pain point in the industry.

[0008] 3. Traditional measures and deficiencies for solving the electro-corrosion problem of the rail transit vehicle traction system at present The first method: Modify the traction motor by adding structures such as slip rings to build a temporary channel for current discharge and forcibly pull down the common-mode voltage of the motor. However, this method has deficiencies such as high modification technical difficulty, long construction period, high modification risk, and increased costs for the operation unit.

[0009] The second method: Optimize the VVVF control strategy to reduce the common-mode voltage output by the VVVF. However, this method has deficiencies such as the lack of a closed-loop control management strategy and is currently only in the research stage and has not been applied in batches in the rail transit field. Summary of the Invention

[0010] In order to overcome the difficulties of large measurement difficulty, high risk, and inability to quantitatively evaluate the shaft current of the traction motor in the traditional rail transit vehicle traction system, and problems such as electro-corrosion of the traction system, the present invention provides an intelligent management system and its algorithm for electro-corrosion of the rail transit vehicle traction system.

[0011] The technical solution adopted by the present invention to achieve the above object is: The rail transit vehicle part includes: TCU, VVVF, and traction motor. The TCU controls and manages the VVVF to output three-phase alternating current with adjustable voltage and frequency to drive the traction motor. The intelligent management system and its algorithm for electro-corrosion of the rail transit vehicle traction system include a hardware device part and a software control part; the hardware device part includes three major parts: a controller and data storage and transmission, a power supply circuit, a display terminal, and a collection terminal; the software control part is completed by the controller, and the controller is built-in with logic control and algorithms; The controller controls the VVVF by collecting signals from the TCU signal, the train level signal for the controller to calculate the acceleration and deceleration of the train, the vehicle load signal, the speed signal, and combines the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals sent by the acquisition terminal, and comprehensively performs logical operations to optimize the PWM signal output by the TCU, and then optimizes the switching angle of the VVVF conduction to obtain the optimal recommended .

[0012] Preferably, the controller, data storage and transmission, and power supply circuits are integrated on a single PCB circuit board and arranged inside the vehicle VVVF chassis; the controller, data storage and transmission, and power supply circuits include a controller, a data storage circuit, a data transmission circuit, and a power supply circuit; the controller, data storage circuit, and data transmission circuit are responsible for system logic operation processing, outputting recommended signals, and performing data storage, transmission, calling, and analysis; The controller uses a high-performance, low-cost, and low-power STM32 single-chip microcomputer with ARM as the core; The data storage circuit stores data such as voltage, current, temperature, and speed sent by the acquisition terminal and the operation data generated by the controller. The data storage medium is an SD card or FLASH storage; The data transmission circuit transmits data with the acquisition terminal, is responsible for receiving data such as voltage, current, temperature, and speed sent by the acquisition terminal, and forwarding these data to the controller. The signal transmission with the acquisition terminal uses a wireless transmission method; the "recommended signal" between the controller and the rail transit vehicle TCU uses optical fiber transmission; The power supply circuit is mainly composed of a power protection short circuit, a power magnetic isolation circuit, a DC / DC conversion circuit, etc., and provides stable power for the controller, display terminal, and acquisition terminal.

[0013] Preferably, the wireless transmission method includes WIFI and 5G interfaces.

[0014] Preferably, the display terminal is located in the driver's cab of the rail transit vehicle and consists of a control and display integrated screen, with a USB port set; the display terminal has a built-in host computer software, communicates with the controller using RS485, and realizes the control function, data display, system fault display, and system data download function of the controller; the control function of the controller includes control commands such as system start, stop, and restart; data display includes generating real-time data graphical curves for monitored signals such as voltage, current, and temperature; system fault display mainly includes abnormal data of monitored variables of each sensor, controller self-fault, etc.; system data download includes the download function through the USB port.

[0015] Preferably, the acquisition terminal is installed on the ventilation opening of the motor filter screen at the shaft extension end of the traction motor of the rail transit vehicle, and includes an installation substrate, a sensor, and a data transmission circuit; the installation substrate of the acquisition terminal is fastened to the ventilation hole of the ventilation hood by bolts. The main body of the installation substrate is made of insulating material using 3D printing technology and designed into a substrate with a thickness of only 3 mm to avoid interference with the rotating parts of the coupling and the motor; sensors for monitoring the voltage, current, speed, and temperature signals of the traction motor shaft are installed on the installation substrate. The sensors send the signals to the controller in a wireless transmission manner through the data transmission device on the substrate; among them, the voltage sensor and the current sensor adopt non-contact Hall sensors. The acquisition principle of the speed sensor is to collect the speed signal by using magnetic patches pasted on the outer surface of the motor rotating shaft; the temperature sensor adopts an infrared temperature sensor; the reference point signal of the above signals is the motor housing.

[0016] Preferably, the software control part introduces the ant colony algorithm; the controller takes the voltage, current, speed, and temperature signals of the traction motor shaft collected as initialization data, first judges its validity, and if it exceeds the range, it is determined as "unreasonable" data, and discards and reloads the data; the train level signal, the signal used by the system monitor TCU to control the VVVF signal, the vehicle load signal, and the speed signal are used as given elements. When the voltage, current, speed, and temperature signals of the traction motor shaft collected increase to the threshold value, adjust the "recommended signal" output by the controller until the voltage, current, speed, and temperature signals of the traction motor shaft collected next time are lower than the threshold value; the pheromone update intensity is the intensity of updating the pheromone of the judgment process passed by the system when finding a new and better path; each judgment is an iteration, and each iteration updates the pheromone for all elements. The original "ant" dies, and the new "ant" makes a new round of judgments; a higher update intensity will make the algorithm converge to the global optimal solution faster; iterate and calculate like this, and finally find the optimal .

[0017] Preferably, the system does not change the acceleration and deceleration of the train under the train level signal to ensure the normal parking accuracy and travel speed of the train; different level signals correspond to PWM signals with different frequencies. When the shaft voltage and shaft current are greater than the threshold value, without changing the vehicle acceleration and deceleration corresponding to the train level, optimize the frequencies and duty cycles of PWM in different time periods of the low speed section, medium speed section, and high speed section of the TCU, so as to optimize the on and off of the IGBT in the VVVF ; finally reduce the common mode voltage generated by the VVVF.

[0018] According to the common mode voltage formula output by the VVVF: = =0 And the phase voltage formula: The common-mode voltage is obtained by using Taylor series expansion And the constraint equations of the modulation frequency and the carrier frequency, =

[0019] When n = 1, 3, 5,... k = 6l, = 1; when n = 2, 4, 6,... k = 6l - 3, = 3; l = 1, 2, 3,... where, Is the DC support circuit voltage on the input side of the VVVF; a is the modulation duty cycle; Is the modulation frequency; Is the carrier frequency; By the recommended du / dt, the TCU optimizes the common-mode voltage by optimizing the modulation frequency and the carrier frequency.

[0020] The beneficial effects of the present invention are: 1. Starting from the root cause of the bearing electrical corrosion problem, aiming at reducing the common-mode voltage of the bearing outer ring, reducing the shaft voltage discharge probability of the bearing.

[0021] 2. The innovation lies in real-time monitoring of the common-mode dynamic voltage, shaft current, motor speed, and motor temperature on the traction motor side, and real-time feedback to this controller, changing the traditional method of "drainage" to "reduction" at the source.

[0022] 3. Design a "real-time" feedback acquisition device for the "common-mode dynamic voltage, current, speed, temperature" of the traction motor bearing, realizing dynamic high-speed acquisition of variables such as motor shaft current, voltage, speed, and temperature, and forming a closed-loop management.

[0023] 4. This system can provide a direct basis for optimizing the control strategy of VVVF to suppress electrical corrosion, and is more efficient and intelligent; 5. Provide an optimal management plan for electrical corrosion without modifying the existing vehicles, greatly saving the vehicle modification cost; 6. Reduce bearing electrical corrosion, extend the bearing service life within the entire life cycle, reduce the workload of early bearing replacement during low-level vehicle repair processes (such as vehicle detention, motor disassembly, bearing replacement, etc.), reduce the procurement cost of bearings as spare parts, and bring huge economic benefits; 7. Effectively reduce the bearing electrical corrosion of the traction system, eliminate potential safety hazards in the operation of rail transit vehicles, and bring huge social benefits; 8. This system uses a high-performance, low-cost, and low-power ARM chip as the controller, with a mature and stable architecture, good system robustness, fast operation, and timely response; 9. The controller and acquisition terminal of the present invention adopt a mainstream processor chip and peripheral circuits, and use sensors that are common in the market, with a simple structure and low manufacturing cost; 10. The acquisition terminal is designed with a clever and flexible structure using 3D printing technology, with a wider applicability; 11. The present invention solves the common problem of electric corrosion of motors in rail transit vehicles, and with a large number of rail transit vehicles in existence, it has a broad prospect for popularization and application; BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Principle block diagram of the intelligent management system for electric corrosion of the traction system of rail transit vehicles; Figure 2 Principle block diagram of the controller, data storage and transmission, and power supply circuits; Figure 3 Axial view of the motor; Figure 4 Installation layout diagram of the acquisition terminal; Figure 5 Software control flowchart; Figure 6 Output voltage waveform of VVVF based on PWM control; Figure 7 Bearing common-mode voltage and electric corrosion path; Figure 8 Corrugated grooves on the outer ring of the bearing and corrosion pits on the rollers caused by electric corrosion. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] As Figure 1 shown, the rail transit vehicle part includes: TCU, VVVF, and traction motor. The TCU controls and manages the VVVF according to the vehicle controller level signal, vehicle load signal, speed signal, etc., so that it outputs three-phase alternating current with adjustable voltage and frequency to drive the three-phase asynchronous induction traction motor. In the field of rail transit vehicles, the load signal is the vehicle weight, which is automatically and real-time collected according to the dynamic changes of passengers, and is used for the exertion of traction power and the adjustment of braking force magnitude to ensure the normal exertion of traction force and accurate parking during braking.

[0026] The intelligent management system for electric corrosion of the traction system of rail transit vehicles and its algorithm of the present invention include a hardware device part and a software control part.

[0027] I. Composition and principle of the hardware device part This system mainly includes three major parts: a controller, data storage and transmission, power supply circuits, a display terminal, and an acquisition terminal. The principle block diagram is as Figure 1 shown. The implementation principle of the entire system: The controller controls the VVVF by collecting the Signals, train level signals (used by the controller to calculate the acceleration and deceleration of the train), vehicle load signals (corresponding to different passenger capacities of the vehicle), speed signals, and in combination with the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals sent by the acquisition terminal, perform comprehensive logical operations to optimize the PWM signals output by the TCU, and then optimize the switching angle of the VVVF conduction to obtain the optimal recommendation . It is possible to reduce the zero-sequence component of the VVVF, thereby reducing the common-mode voltage, and ultimately reducing the shaft voltage and shaft current of the traction motor bearings, reducing the electrical corrosion of the bearings, and thus forming a closed-loop control for the electrical corrosion management of the traction system.

[0028] 1. The controller, data storage and transmission, and power supply circuits are integrated on a single PCB circuit board and arranged in the vehicle VVVF chassis. Its principle block diagram is as Figure 2 shown. The controller, data storage and transmission, and power supply circuits include a controller, a data storage circuit, a data transmission circuit, and a power supply circuit; the controller, data storage circuit, and data transmission circuit are responsible for the system logic operation processing, outputting the recommended signals, and performing data storage, transmission, calling, and analysis.

[0029] The controller uses a high-performance, low-cost, and low-power STM32 single-chip microcomputer with ARM as the core, with built-in logic control and algorithms.

[0030] The data storage circuit stores data such as voltage, current, temperature, and speed sent by the acquisition terminal and the operation data generated by the controller. The data storage medium is an SD card or FLASH storage; The data transmission circuit conducts data transmission with the acquisition terminal, is responsible for receiving data such as voltage, current, temperature, and speed sent by the acquisition terminal, and forwarding these data to the controller. The signal transmission with the acquisition terminal uses a wireless transmission method (WIFI or 5G interface). The "recommended signals" between the controller and the TCU of the rail transit vehicle are transmitted by optical fiber to enhance the anti-interference ability.

[0031] The power supply circuit is mainly composed of a power supply protection short circuit, a power supply magnetic isolation circuit, a DC / DC conversion circuit, etc., and provides stable power for the controller, display terminal, and acquisition terminal.

[0032] 2. The display terminal is located in the driver's cab of the rail transit vehicle and is composed of an integrated control and display screen, with a USB port set. The display terminal is built-in with a host computer software and communicates with the controller via RS485 to achieve functions such as controlling the controller, data display, system fault display, and system data download. The control functions for the controller include control commands such as system startup, stop, and restart; data display includes generating real-time data graphical curves for monitored signals such as voltage, current, and temperature; system fault display mainly includes abnormal data of monitored variables by each sensor and the controller's own faults, etc.; system data download includes the download function through the USB port.

[0033] 3. The acquisition terminal is installed on the ventilation opening of the motor filter screen at the shaft extension end of the traction motor of the rail transit vehicle and includes an installation substrate, sensors, and a data transmission circuit. Its function is to collect and transmit signals of the shaft voltage, shaft current, shaft speed, and shaft temperature of the traction motor. Its installation position is as Figure 3 shown, and its principle block diagram is as Figure 4 shown. The installation substrate of the acquisition terminal is fastened to the ventilation hole of the ventilation cover by bolts. The main body of the installation substrate is made of insulating material using 3D printing technology and is designed into a substrate with a thickness of only 3 mm to avoid interference with the rotating parts of the coupling and the motor. Sensors for monitoring the shaft voltage, current, speed, and temperature of the traction motor are installed on the installation substrate. The sensors send the signals to the controller in a wireless transmission manner (WIFI or 5G interface) through the data transmission device on the substrate. Among them, the voltage sensor and the current sensor use non-contact Hall sensors. The acquisition principle of the speed sensor is to collect the speed signal by pasting magnetic patches on the outer surface of the motor shaft, which not only ensures the sampling accuracy but also has reliable non-contact isolation; the temperature sensor uses an infrared temperature sensor. The reference point signal for the above signals is the motor housing.

[0034] II. Composition of the software control part The software control part of this system is completed by the controller, which is built-in with logic control and algorithms. The present invention introduces the ant colony algorithm, which shows excellent effects in the optimization of continuous data. The controller takes the collected signals of the shaft voltage, shaft current, shaft speed, and shaft temperature of the traction motor as initialization data, first judges its validity, and if it exceeds the range, it is determined as "unreasonable" data, and discards and reloads the data. Taking the train level signal and the signal used by the system monitor TCU to control the VVVF as given elements, when the collected signals of the shaft voltage, shaft current, shaft speed, and shaft temperature of the traction motor increase to the threshold, adjust the "recommended" output by the controller signal. When the collected signals of the shaft voltage, shaft current, shaft speed, and shaft temperature of the traction motor increase to the threshold, adjust the "recommended" output by the controller The "signal" lasts until the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals collected next time are lower than the threshold. The pheromone update intensity is the intensity of updating the pheromone of the judgment process passed by the system when it finds a new and better path. Each judgment is an iteration. For each iteration, pheromone update is performed on all elements. The original "ant" dies, and a new "ant" makes a new round of judgment. A higher update intensity will make the algorithm converge to the global optimal solution faster. Through such iterative calculation, the optimal solution is finally found. The software control flowchart is as Figure 5 shown.

[0035] Software control principle: This system does not change the acceleration and deceleration of the train under the train level signal to ensure the normal parking accuracy and travel speed of the train. Different level signals correspond to PWM signals of different frequencies. When the shaft voltage and shaft current are greater than the threshold, without changing the vehicle acceleration and deceleration corresponding to the train level, the frequencies and duty cycles of PWM in different time periods of the low-speed section, medium-speed section, and high-speed section of the TCU are optimized, so as to optimize the opening and closing of IGBTs in the VVVF. Ultimately, the common-mode voltage generated by the VVVF is reduced.

[0036] According to the formula for the common-mode voltage output by the VVVF: = = 0 And the formula for the phase voltage: Using Taylor series expansion to obtain the constraint equation of the common-mode voltage with the modulation frequency and the carrier frequency, =

[0037] When n = 1, 3, 5,... k = 6l, = 1; when n = 2, 4, 6,... k = 6l - 3, = 3; l = 1, 2, 3,... where, is the DC support circuit voltage on the input side of the VVVF; a is the modulation duty cycle; is the modulation frequency; is the carrier frequency.

[0038] Through the recommended du / dt, the TCU optimizes the common-mode voltage by optimizing the modulation frequency and the carrier frequency.

Claims

1. Electric corrosion intelligent management system and its algorithm for the traction system of rail transit vehicles. The rail transit vehicle part includes: TCU, VVVF and traction motor. The TCU controls and manages the VVVF to output three-phase alternating current with adjustable voltage and frequency to drive the traction motor. It is characterized in that it includes a hardware device part and a software control part; the hardware device part includes a controller, a data storage and transmission part, a power supply circuit, a display terminal and a collection terminal; the software control part is completed by the controller, and the controller is built-in with logic control and algorithms. The controller controls the VVVF by collecting signals from the TCU signals, train level signals for the controller to calculate the acceleration and deceleration of the train, vehicle load signals, speed signals, and combines the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals sent by the acquisition terminal collected, and comprehensively performs logical operations to optimize the PWM signal output by the TCU, and then optimizes the switching angle of the VVVF conduction, and obtains the optimal recommendation .

2. The intelligent management system and its algorithm for electric corrosion of the traction system of rail transit vehicles according to claim 1, characterized in that: The controller, the data storage and transmission part, and the power supply circuit are integrated on a PCB circuit board and arranged in the VVVF chassis of the vehicle; the controller, the data storage and transmission part, and the power supply circuit include a controller, a data storage circuit, a data transmission circuit and a power supply circuit. The controller, data storage circuit, and data transmission circuit are responsible for system logic operation processing, outputting the recommended signal, and performing data storage, transmission, call, and analysis; The controller uses a high-performance, low-cost, and low-power STM32 single-chip microcomputer with ARM as the core. The data storage circuit stores data such as voltage, current, temperature, speed, etc. sent by the collection terminal and the operation data generated by the controller. The data storage medium is an SD card or FLASH storage. The data transmission circuit conducts data transmission with the acquisition terminal, responsible for receiving data such as voltage, current, temperature, speed, etc. sent by the acquisition terminal, and forwarding this data to the controller. The signal transmission with the acquisition terminal adopts a wireless transmission method; the "recommended signal" between the controller and the TCU of the rail transit vehicle is transmitted by optical fiber; The power supply circuit is mainly composed of a power protection short circuit, a power magnetic isolation circuit, a DC / DC conversion circuit, etc., to provide stable power for the controller, the display terminal, and the collection terminal.

3. The intelligent management system for electric corrosion of the rail transit vehicle traction system and its algorithm according to claim 1, characterized in that: The display terminal is located in the driver's cab of the rail transit vehicle and is composed of a control and display integrated screen, and is provided with a USB port; the display terminal is built-in with upper computer software and communicates with the controller via RS485 to achieve the control function of the controller, data display, system fault display, and system data download function; the control function of the controller includes control commands such as system start, stop, restart, etc.; data display includes generating real-time data graphical curves for monitored signals such as voltage, current, temperature, etc.; system fault display mainly includes abnormal monitored variable data of each sensor, controller self-fault, etc.; system data download includes the download function through the USB port.

4. The intelligent management system for electric corrosion of the rail transit vehicle traction system and its algorithm according to claim 1, characterized in that: The collection terminal is installed on the ventilation opening of the motor filter screen at the shaft extension end of the traction motor of the rail transit vehicle and includes a mounting substrate, sensors and a data sending circuit; the mounting substrate of the collection terminal is fastened to the ventilation hole of the ventilation cover by bolts. The main body of the mounting substrate is designed into a substrate with a thickness of only 3 mm using 3D printing technology with insulating materials to avoid interference with the rotating parts of the coupling and the motor; sensors for monitoring the voltage, current, speed, and temperature signals of the traction motor shaft are installed on the mounting substrate. The sensors send the signals to the controller in a wireless transmission manner through the data transmission device on the substrate; among them, the voltage sensor and the current sensor adopt non-contact Hall sensors, and the acquisition principle of the speed sensor is to acquire the speed signal by pasting magnetic patches on the outer surface of the motor shaft; the temperature sensor adopts an infrared temperature sensor; the reference point signal of the above signals is the motor housing.

5. The intelligent management system and algorithm for electric corrosion of the traction system of rail transit vehicles according to claim 1, characterized in that: The software control part introduces the ant colony algorithm; the controller takes the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals collected as initialization data, first judges their validity, and if they exceed the range, they are judged as "unreasonable" data, and the data is discarded and reloaded; the train level signal, vehicle load signal, speed signal, and the signal used by the system monitoring TCU to control the VVVF are used as given elements. When the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals collected increase to the threshold value, the "recommended signal" output by the controller is adjusted until the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals collected next time are lower than the threshold value; the pheromone update intensity is the intensity of updating the pheromone of the judgment process passed by the system when it finds a new and better path; each judgment is an iteration, and each time an iteration is performed, the pheromone of all elements is updated once, the original "ant" dies, and the new "ant" makes a new round of judgments; a higher update intensity will make the algorithm converge to the global optimal solution faster; through such iterative calculation, the optimal solution is finally found. When the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals collected increase to the threshold value, the "recommended signal" output by the controller is adjusted until the traction motor shaft voltage, shaft current, shaft speed, and shaft temperature signals collected next time are lower than the threshold value. The pheromone update intensity is the intensity of updating the pheromone of the judgment process passed by the system when it finds a new and better path; each judgment is an iteration, and each time an iteration is performed, the pheromone of all elements is updated once, the original "ant" dies, and the new "ant" makes a new round of judgments; a higher update intensity will make the algorithm converge to the global optimal solution faster; through such iterative calculation, the optimal solution is finally found. .

6. The intelligent management system for electric corrosion of the rail transit vehicle traction system and its algorithm according to claim 1, characterized in that: This system does not change the acceleration and deceleration of the train under the train level signal to ensure the normal stopping accuracy and travel speed of the train; different level signals correspond to PWM signals of different frequencies. When the axle voltage and axle current are greater than the threshold value, without changing the vehicle acceleration and deceleration corresponding to the train level, the frequencies and duty cycles of PWM in different time periods of the low-speed section, medium-speed section and high-speed section of the TCU are optimized, so as to optimize the opening and closing of IGBT in the VVVF ; ultimately reduce the common-mode voltage generated by the VVVF.

7. The intelligent management system for electric corrosion of the rail transit vehicle traction system and its algorithm according to claim 2, characterized in that: The wireless transmission method includes WIFI and 5G interfaces.

8. The intelligent management system for electric corrosion of the rail transit vehicle traction system and its algorithm according to claim 6, characterized in that: According to the VVVF output common-mode voltage formula: = =0； And the phase voltage formula: Obtaining the common-mode voltage by using Taylor series expansion and the constraint equations of the modulation frequency and the carrier frequency = ； When n = 1, 3, 5, ..., k = 6l, = 1; when n = 2, 4, 6, ..., k = 6l - 3, = 3; where l = 1, 2, 3, ... In the formula, is the DC support circuit voltage on the input side of the VVVF; a is the modulation duty cycle; is the modulation frequency; is the carrier frequency; Through the recommended du / dt, the TCU optimizes the modulation frequency and carrier frequency, and then optimizes the common-mode voltage.

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