CN114559824B - Traction system based on railway vehicle and verification method - Google Patents

The application relates to the technical field of rail vehicles and discloses a traction system and a verification method based on the rail vehicles, wherein the traction system comprises a power supply module, an inversion module and a motor module; the power supply module is electrically connected with the inversion module and is used for providing a direct-current power supply for the inversion module; the inversion module is used for converting a direct-current power supply into an alternating-current power supply suitable for the motor module; the motor module comprises two groups of linear motors which are connected in parallel, the number of each group of linear motors is three, and the motor module is used for providing traction function or braking function for the railway vehicle. The application has the effect of enhancing the balance of the output current of the inverter, thereby meeting the requirement of traction braking characteristics of the railway vehicle.

Traction system based on railway vehicle and verification method

Technical Field

The invention relates to the technical field of railway vehicles, in particular to a traction system based on a railway vehicle and a verification method.

Background

Rail traffic refers to a type of vehicle or transportation system in which an operating vehicle needs to travel on a particular track. The most typical rail traffic is a railway system consisting of conventional trains and standard railroads. With the diversification development of train and railway technologies, rail traffic is of more and more types, and is widely applied to urban public transportation in medium and short distances as well as land transportation in long distances.

The traction system is a core component of the railway vehicle, is a source of power of the train, provides traction force and braking force for the train according to the requirement, and completes traction and braking of the train.

In the running process of the railway vehicle, the traction system generally comprises a linear motor and an inverter, the linear motor is controlled to work through a power supply converted by the inverter, the railway vehicle is driven to be pulled or braked by the motor, the number of the motors contained in each traction system is different, and the combination mode and the setting mode of the traction system also determine the effect of pulling or braking.

In view of the above-mentioned related art, the inventors consider that the current combination of the linear motor has poor balance of the inverter output current, and it is difficult to satisfy the requirements of traction and braking characteristics of the railway vehicle.

Disclosure of Invention

In order to enhance the balance of the output current of the inverter and meet the requirements of traction and braking characteristics of a railway vehicle, the application provides a traction system based on the railway vehicle and a verification method.

In a first aspect, the present application provides a traction system based on a rail vehicle, which adopts the following technical scheme:

A traction system based on a rail vehicle comprises a power supply module, an inversion module and a motor module;

The power supply module is electrically connected with the inversion module and is used for providing a direct-current power supply for the inversion module;

The inversion module is used for converting a direct-current power supply into an alternating-current power supply suitable for the motor module;

the motor module comprises two groups of linear motors which are connected in parallel, the number of each group of linear motors is three, and the motor module is used for providing traction function or braking function for the railway vehicle.

By adopting the technical scheme, the three-phase winding of the motor module receives three-phase symmetrical alternating current with adjustable frequency and voltage from the inversion module, generates a travelling wave magnetic field, interacts with the secondary of the motor module fixed on the magnetic conduction steel rail to generate electromagnetic thrust to drive the vehicle to advance, the inversion module drives 6 linear motors, the inversion module is integrated with an overvoltage suppression unit, and when the voltage of a power grid changes from 500V to 900V, the overvoltage suppression unit can control the normal work of a main circuit and conveniently realize contactless conversion of traction and braking, thereby enhancing the balance of output current of the inverter and meeting the requirements of traction and braking characteristics of a train.

Optionally, a branching module is electrically connected between the power supply module and the inversion module, and the branching module is electrically connected with a standby power supply module;

The standby power supply module comprises a charger and a storage battery which are electrically connected;

the charger is electrically connected with the branching module and is used for adjusting the voltage level of the direct current power supply provided by the power supply module and supplying power to the storage battery through the direct current power supply with the adjusted voltage level;

the storage battery is used for providing standby power for the motor module.

Through adopting above-mentioned technical scheme, power module is when supplying power for motor module, through the separated time module, can divide into the multichannel with the power that power module provided, supplies power for motor module all the way, and the stand-by power supply is supplied with power for the other way, supplies power for the battery through the machine that charges to can provide the power supply for motor module when power module receives the influence, thereby guarantee that traction system can normal operating.

Optionally, the system further comprises a control module and a monitoring module, wherein the control module is electrically connected with the standby power supply module and the inversion module respectively;

The control module is used for sending a traction instruction to the motor module when the railway vehicle is started, and controlling the motor module to realize the traction function of the railway vehicle;

the speed limiting device is also used for sending a speed limiting instruction to the motor module when the speed of the railway vehicle exceeds a speed threshold value, and controlling the motor module to realize the speed reducing function of the railway vehicle;

The monitoring module is used for acquiring whether various electrical parameter values of the motor module and the inversion module are in a threshold range or not, wherein the various electrical parameters comprise intermediate direct current loop voltage, grounding current, converter cooling time and motor module cooling time.

By adopting the technical scheme, the control module is arranged, and can send a traction instruction to control the motor module to act, so that the traction railway vehicle moves on an uphill road section, and meanwhile, when some downhill road sections are met, the speed of the railway vehicle needs to be limited in order to prevent the speed of the railway vehicle from being too high, and then the speed limiting instruction is sent to control the motor module to reduce the speed of the railway vehicle; then in the running process of the rail vehicle, the monitoring module is required to monitor the parameter values of the intermediate direct current loop voltage, the grounding current, the cooling time of the converter and the cooling time of the motor module, and the monitoring function can be achieved in the working process of the traction system, so that a certain risk is reduced.

Optionally, the inversion module adopts IGBT elements, and comprises an integrated three-phase inversion unit and a brake chopper unit.

By adopting the technical scheme, the IGBT element has the advantages of small driving power and high switching speed of the MOSFET device, and also has the advantages of reduced saturation voltage and large capacity of the bipolar device, and the three-phase inversion unit and the brake chopper unit can realize the effect of rapidly switching on and off the channel.

Optionally, the system further comprises a traction speed measurement module, wherein the traction speed measurement module is in communication connection with the control module and is used for receiving a speed measurement instruction sent by the control module and measuring the speed of the railway vehicle;

The traction speed measurement module comprises at least one eddy current induction sensor, wherein the eddy current induction sensor is used for generating eddy current induction current based on movement of the railway vehicle and outputting detection pulse signals to the control module;

The traction speed measurement module further comprises a processor, wherein the processor is used for acquiring the time difference of the rising edge of the pulse based on the detection pulse signal and outputting the running speed of the railway vehicle based on the moving distance of the railway vehicle.

Through adopting above-mentioned technical scheme, through the module that tests the speed of traction speed, at the in-process that rail vehicle moved, can survey rail vehicle's speed, when survey speed, adopt the mode that vortex sensor scanned the sleeper to produce the speed, when the metal target object was close, produced an induced current (eddy current) between sensor and the metal target object, along with the metal target object is more close, the sensor induced current is strengthened more, causes the load in the oscillating circuit to increase, then the vibration weakens until stopping. The sensor detects a change in oscillation state using the amplitude and outputs a detection pulse signal. The processor reads the signals filtered by the sampling circuit, and then obtains the actual running speed of the train according to the time difference of the rising edges of the pulses and the speed equal to the distance divided by the time; by adopting the method, the moving speed of the railway vehicle can be obtained in real time, so that the obtained moving speed is more accurate.

In a second aspect, the application provides a traction verification method based on a rail vehicle, which adopts the following technical scheme:

the traction verification method based on the rail vehicle is applied to the traction system based on the rail vehicle, and comprises the following steps:

acquiring the self weight of the railway vehicle;

Based on the self weight, acquiring the vehicle converted weight of the railway vehicle under the inertia condition;

acquiring basic resistance and additional resistance of the railway vehicle;

Based on the electrical characteristics of the motor module, obtaining the traction force of the railway vehicle;

acquiring the acceleration of the railway vehicle based on the vehicle converted weight, traction force, basic resistance and additional resistance of the railway vehicle;

and if the acceleration of the railway vehicle reaches the acceleration threshold value, checking the traction system of the railway vehicle to be qualified.

By adopting the technical scheme, when the validity of the traction system is required to be checked, whether the acceleration value of the traction system of the railway vehicle reaches the requirement or not needs to be judged, the acceleration value is influenced by the parameter values of the traction force, the basic resistance and the additional resistance of the railway vehicle, the acceleration value is acquired again when the traction force, the basic resistance and the additional resistance are acquired, and then the threshold value comparison is carried out to judge whether the traction system reaches the standard or not, so that the validity of the traction system is obtained.

Optionally, the step of obtaining the basic resistance of the railway vehicle includes:

Respectively acquiring air resistance and electromagnetic resistance of the current environment of the railway vehicle:

the air resistance is obtained by satisfying the following formula:

Wherein W _a represents air resistance, unit N; c _d represents a drag coefficient, depending on the shape of the train; ρ represents the air density in kg/m ³, 1.293kg/m ³ in the standard case; v represents the running speed of the vehicle in the static wind state, and the unit is m/s; v _a denotes upwind wind speed in m/s; s is the largest windward sectional area of the train, and the unit is m ²;

The acquisition of electromagnetic resistance satisfies the following formula:

Wherein W _m represents electromagnetic resistance, unit N; m represents the converted weight of the vehicle, and the unit t; k, a, b represent constants; v represents the running speed of the vehicle in m/s; v _m denotes the turning speed in m/s.

By adopting the technical scheme, when the basic resistance of the railway vehicle is acquired, the air resistance and the electromagnetic resistance of the current environment are required to be acquired, the air resistance comprises the resistance under the static wind condition and the resistance under the upwind condition, and then the air resistance is calculated according to the resistance coefficient and the air density; when the electromagnetic resistance is calculated, the calculated weight is required to be determined according to the vehicle, meanwhile, the electromagnetic resistance is also determined according to the running speed of the vehicle, and the calculation mode of the electromagnetic resistance is determined according to different speed interval ranges, so that the accuracy of calculating the electromagnetic resistance is improved.

Optionally, the step of obtaining the additional resistance of the railway vehicle includes:

The acquisition of additional resistance of the railway vehicle satisfies the following formula: w _i = M x 9.81 x c, where M represents train mass and c represents ramp index; m represents the vehicle converted weight, unit t.

Through adopting above-mentioned technical scheme, when the angle of ramp appears changing, its corresponding ramp index also can change, then vehicle conversion weight is also different, can calculate the additional resistance under different weight, the ramp condition according to this formula, has the suitability.

Optionally, the step of acquiring the acceleration of the rail vehicle includes:

The acquisition of the acceleration of the rail vehicle satisfies the following formula: a= (F _{Traction and pull} -F _{Basic, basic} -c*W_i)/M, where F _{Traction and pull} is traction, F _{Basic, basic} is base resistance, W _i is additional resistance, c represents the ramp index; m represents the vehicle converted weight, unit t.

By adopting the technical scheme, when the acceleration of the rail transit vehicle is acquired, the traction force of the rail transit vehicle is required to be subtracted by the basic resistance and the additional resistance, and the ratio of the calculated value to the vehicle converted weight is the acceleration of the rail transit vehicle.

In summary, the present application includes at least one of the following beneficial technical effects:

1. The three-phase winding of the motor module receives three-phase symmetrical alternating current with adjustable frequency and voltage from the inversion module to generate a travelling wave magnetic field, the travelling wave magnetic field interacts with the secondary of the motor module fixed on the magnetic conduction steel rail to generate electromagnetic thrust to drive the vehicle to advance, the inversion module drives 6 linear motors, the inversion module is integrated with an overvoltage suppression unit, and when the voltage of a power grid changes within a certain range, the overvoltage suppression unit can control the main circuit to normally work and conveniently realize contactless conversion of traction and braking, so that the balance of the output current of the inverter is enhanced, and the requirements of the traction and braking characteristics of a train are met;

2. Then in the running process of the rail vehicle, the monitoring module is required to monitor the parameter values of the intermediate direct current loop voltage, the grounding current, the cooling time of the converter and the cooling time of the motor module, and the monitoring function can be achieved in the working process of the traction system, so that a certain risk is reduced.

Drawings

Fig. 1 is a schematic diagram of a hardware architecture of a traction system based on a rail vehicle according to an embodiment of the present application.

Fig. 2 is a wiring diagram of the motor module of fig. 1.

Fig. 3 is a schematic diagram of the traction velocimetry system of fig. 1.

Fig. 4 is a flow chart of a traction verification method based on a rail vehicle according to an embodiment of the present application.

Fig. 5 is a graph of the basic drag curve versus speed curve for a stator load (AW 2) and an overrun load (AW 3) of an embodiment of the present application.

Fig. 6 is a graph of the DC750V traction versus speed curve referred to in S400 of fig. 5.

Detailed Description

The application is described in further detail below with reference to fig. 1-6.

Referring to fig. 1, the embodiment of the application discloses a traction system based on a railway vehicle, which comprises a power supply module, an inversion module, a branching module, a standby power supply module, a motor module, a control module, a monitoring module and a traction speed measuring module.

The power supply module can be a super capacitor, and the super capacitor is responsible for supplying power DC750V to the whole train, and the high-voltage junction box receives 750V voltage and supplies power for the 110V standby power supply module and the inversion module respectively.

The inverter module comprises an inverter unit and an inverter box, wherein the inverter unit is integrated in the VVF inverter box. The inverter unit adopts IGBT elements, is a two-level inverter circuit, integrates a three-phase bridge arm (a three-phase inverter unit) and a braking phase bridge arm (a braking chopper unit) of the three-phase inverter, and drives the motor module to work. The inverter module adopts a forced air cooling mode.

The inversion module further comprises a control Device (DCU), wherein the DCU mainly completes real-time control and overvoltage chopping control on the IGBT elements and the motor module, and simultaneously has a complete traction converter system fault protection function, a module-level fault self-diagnosis function, a certain degree of fault self-resetting function and a part of vehicle-level control function, and the DCU is a part of a train communication network and is communicated with an MVB interface. The DCU is integrated in the VVVF inverter box.

The technical parameters of the inversion module are as follows:

1. rated input voltage: DC750V;

2. Rated capacity: 670kVA;

3. rated output current: 750A (active);

4. switching frequency: 750Hz;

5. efficiency of rated operating point: 0.98;

6. The cooling mode is as follows: forced air cooling of the heat pipe;

7. Body size of the box: 1400mm 900mm 560 mm;

8. weight: less than 370kg;

ip rating: IP55;

10. material quality: an aluminum alloy;

11. dielectric withstand voltage (main circuit to ground): AC4500V,1min;

12. protection grade: IP55.

The branching module is specifically a high-voltage branching box, the high-voltage branching box connects high-voltage power supply straddles of the whole railway vehicle, and main parameters of the high-voltage branching box are as follows:

1. rated input voltage: DC750V;

2. Input voltage range: DC 500V-DC 900V;

3. Protection grade: IP55;

4. external dimensions: 440mm x 740mm x 380mm (length x width x height).

The standby power supply module is electrically connected with the high-voltage junction box and comprises a 110V charger and a storage battery, and the 110V charger converts a DC750V power supply into a DC110V power supply to supply power to the storage battery and other vehicle-mounted loads.

The motor module comprises 6 linear motors, the three-phase windings of the linear motors receive three-phase symmetrical alternating current with adjustable frequency and voltage from the traction inverter, a traveling wave magnetic field is generated, and electromagnetic thrust is generated by interaction with the secondary of the linear motors fixed on the magnetic conduction steel rail to push the vehicle to advance or retreat. One traction inverter supplies power for 6 linear motors (2 strings of 3 parallel motors, namely two groups of linear motors connected in parallel, and the number of each group of linear motors is three). The wiring of the linear motor is shown in fig. 2, and comprises the linear motors 1,2, 3, 4, 5 and 6 marked by serial numbers, wherein the traction inverter in the drawing is an inversion module, and three groups of linear motors which are connected in parallel are connected through two junction boxes so as to eliminate unbalance of output current of the traction inverter as much as possible.

The parameters of the linear motor are as follows:

1. rated line voltage: AC257V;

2. starting current: 535A;

3. number of poles: 12 poles;

4. insulation grade: a H level;

5. Mechanical air gap: 13mm.

The control module is composed of a central processing unit pre-storing an operation program and adopts a TCN network conforming to IEC61375 standard. The train control level bus is composed of an MVB vehicle bus, and the MVB bus is redundant through double lines. When the railway vehicle is started, a traction instruction is sent to the motor module, and the motor module is controlled to realize the traction function of the railway vehicle; and the speed limiting command is sent to the motor module when the speed of the railway vehicle exceeds a speed threshold (for example, 300 km/h), and the motor module is controlled to realize the speed reduction function of the railway vehicle. And the linear motor traction control device is also used for interlocking traction of the linear motor and limiting grid voltage and grid power.

The monitoring module is used for acquiring whether various electric parameter values of the motor module and the inversion module are in a threshold range or not, wherein the various electric parameter values comprise intermediate direct-current loop voltage, grounding current, converter cooling time and motor module cooling time.

The traction speed measurement module comprises a processor and at least one eddy current induction sensor, and the small magnetic levitation vehicle generates speed by adopting a mode that the eddy current induction sensor scans the sleeper for the traction system. The working principle of the induction sensor is as follows: when the metal object of the railway vehicle approaches, an induced current (eddy current) is generated between the induction sensor and the metal object, and as the metal object approaches, the induced current of the induction sensor increases, so that the load in the oscillating circuit increases, and then the oscillation decreases until the oscillation stops. The sensor detects a change in oscillation state using the amplitude and outputs a detection pulse signal. The processor reads the signals filtered by the sampling circuit, and then obtains the actual running speed of the train according to the time difference of the rising edges of the pulses and the speed equal to the distance divided by the time; the schematic diagram is shown in fig. 3, two eddy current induction sensors in fig. 3 are installed on a magnetic levitation track through two installation plates, a TCMS in fig. 3 is a control module, a DCU in the diagram is a control device of a traction inverter, the DCU is a part of a train communication network, and the DCU is communicated with an MVB interface.

A. The main parameters of the speed measuring system are as follows:

input power range: 110V (-30% to +25%), 1A;

Ambient temperature: -25 to +45 ℃;

operating temperature: -25 to +70 ℃;

storage temperature: -40 to +75 ℃;

storage and short use temperature: -25 to +75 ℃;

maximum relative humidity: less than or equal to 100 percent (the average minimum temperature in the month is not lower than 25 ℃).

B. The speed measuring system requires for sleeper:

The upper surface of the sleeper is made of metal materials; the center distance between sleeper centers, sleeper width, and specific technical requirements for the non-sleeper section are determined in the design communication stage.

C. The speed measuring system has the technical requirements that:

Providing a speed signal for a vehicle traction and braking system; the speed measurement control device and the speed measurement sensor used for the same purpose on the railway vehicle subsystem can be completely interchanged; measuring the speed by adopting a non-contact sleeper metering speed test technology and adopting a pulse counting method; has a self-test function.

The implementation principle of the traction system based on the rail vehicle provided by the embodiment of the application is as follows: when the traction system works, the power supply module is responsible for supplying power DC750V to the whole train, the high-voltage junction box receives 750V voltage and supplies power for the 110V standby power supply module and the inversion module respectively, and the linear motor drives the railway vehicle to carry out traction or braking; the standby power supply module provides a standby power supply for the linear motor; the monitoring module monitors whether various electrical parameter values of the motor module and the inversion module are positioned in a threshold range at any time; the traction speed measuring module is used for receiving the speed measuring instruction sent by the control module and measuring the speed of the railway vehicle.

Based on the hardware architecture, referring to fig. 4, the embodiment of the application also discloses a traction verification method based on a rail vehicle, which comprises the following steps of S100-S600:

Step S100: the own weight of the rail vehicle is obtained.

For example, the weights of the trains under different load conditions are shown in the attached table:

the attached table: weight of train under different load conditions

Step S200: and acquiring the vehicle converted weight of the railway vehicle under the inertia condition based on the self weight.

The conversion mass of the train inertia satisfies the formula: m= (mc1+mc2) ×β1+t×β2, and β1 and β2 are both inertia coefficients.

For example, if β1 takes on 0.8 and β2 takes on 0.9, then M (AW 2) =19.5×2×0.8+19×0.9=48.3 t.

Step S300: the basic resistance and the additional resistance of the rail vehicle are obtained.

The small-sized magnetic levitation train has no starting friction force, and other factors generate small resistance, so that the starting resistance does not need to be calculated independently.

(1) The basic resistance is irrelevant to the line condition and mainly comprises air resistance, electromagnetic resistance and random disturbance resistance, wherein the random disturbance resistance cannot be calculated, has a smaller value and is ignored in calculation.

Respectively acquiring air resistance and electromagnetic resistance of the current environment of the railway vehicle:

the air resistance W _a increases as the speed of the small maglev train increases, as a quadratic function of speed, and is the main resistance of the train during high-speed operation. The size is determined by the resistance coefficient, the air density, the running speed and the maximum cross-sectional area of the train:

The air resistance W _a is obtained satisfying the following formula:

Wherein W _a represents air resistance, unit N; c _d represents a drag coefficient, depending on the shape of the train; ρ represents the air density in kg/m ³, 1.293kg/m ³ in the standard case; v represents the running speed of the vehicle in the static wind state, and the unit is m/s; v _a denotes upwind wind speed in m/s; s is the largest windward sectional area of the train, and the unit is m ².

The air resistance of the small-sized magnetic levitation train is as follows:

Wherein W _a units are newtons; n represents the number of vehicles; v is in m/s.

The acquisition of electromagnetic resistance satisfies the following formula:

Wherein W _m represents electromagnetic resistance, unit N; m represents the converted weight of the vehicle, and the unit t; k, a, b represent constants; v represents the running speed of the vehicle in m/s; v _m denotes the turning speed in m/s.

The step of obtaining additional resistance of the rail vehicle comprises:

The acquisition of additional resistance of the railway vehicle satisfies the following formula: w _i = M x 9.81 x c, where M represents the vehicle converted weight and c represents the ramp index; m represents the vehicle converted weight, unit t.

The basic drag curve versus speed for a train under a constant load (AW 2) and an overrun load (AW 3) is shown in fig. 5, where there is some error and overall greater drag.

(2) The additional resistance is related to the line condition and mainly consists of the ramp additional resistance and the curve additional resistance. The small-sized magnetic levitation train levitation guide electromagnet only allows extremely small dynamic adjustment at the balance position, so that the transverse deviation between the linear motor stator and the reaction plate is small, the influence on the magnetic resistance is small, and the curve additional resistance of the small-sized magnetic levitation train is negligible.

The acquisition of additional resistance of the railway vehicle satisfies the following formula: w _i = M x 9.81 x c, where M represents the vehicle converted weight and c represents the ramp index; m represents the vehicle converted weight, unit t.

The additional resistance at 36% of maximum ramp is:

(AW0)：W_i0=M0*9.81*36‰=16.4kN；

(AW2)：W_i2=M2*9.81*36‰=21.3kN；

(AW3)：W_i3=M3*9.81*36‰=22.7kN。

Step S400: and acquiring traction force of the railway vehicle based on the electrical characteristics of the motor module.

Based on the electrical characteristics of the motor module (two strings three parallel), as shown in fig. 6: obtaining a DC750V traction-speed curve, it is seen that the traction force of the overman load and the stator load is the same in terms of traction force, and is always maintained at about 57kN in the range of 0-40km/h, and the traction force tends to decrease after the speed exceeds 45 km/h.

Under the AW2 and AW3 loads, the total traction force is 57kN, 12 motors are used, and the maximum traction force corresponding to each motor is about 4.75kN.

Step S500: and acquiring the acceleration of the railway vehicle based on the vehicle converted weight, traction force, basic resistance and additional resistance of the railway vehicle.

The step of acquiring the acceleration of the railway vehicle comprises the following steps:

The acquisition of the acceleration of the rail vehicle satisfies the following formula: a= (F _{Traction and pull} -F _{Basic, basic} -c*W_i)/M, where F _{Traction and pull} is traction, F _{Basic, basic} is base resistance, W _i is additional resistance, c represents the ramp index; m represents the vehicle converted weight, unit t.

For example, c has a value of 36 per mill, F _{Traction and pull} is 57kN, F _{Basic, basic} is 51.384kN, W _i is 44kN, and M is 48t, and the acceleration a is 0.084m/s ².

Step S600: and if the acceleration of the railway vehicle reaches the acceleration threshold value, checking the traction system of the railway vehicle to be qualified.

For example, an acceleration threshold of 0.083m/s ² is satisfactory.

The above embodiments are not intended to limit the scope of the present application, so: all equivalent changes in structure, shape and principle of the application should be covered in the scope of protection of the application.