阅读说明：本技术 模块化轨道交通电阻制动能量吸收装置循环控制方法 (Circulation control method for modular rail transit resistive braking energy absorption device ) 是由 刘春松 杨轶成 张裕峰 王结飞 李冰 于 2019-11-15 设计创作，主要内容包括：本发明公开了一种模块化轨道交通电阻制动能量吸收装置循环控制方法,该方法基于轨道交通再生能量电阻吸收装置平台,N个功率模块中只有1个模块工作在PWM调制模式,其余N-1个功率模块工作在直通模式。工作在PWM模式下的功率模块采用循环模式进行工作；直通模式下功率模块的投入顺序按照上一时段统计时长确定投入顺序。本发明方法可以使得功率器件的开关次数大幅度减小,功率器件的温度波动更平缓,从而提高装置的寿命。(The invention discloses a circulation control method of a modular rail transit resistance braking energy absorption device, which is based on a rail transit regenerative energy resistance absorption device platform, wherein only 1 module of N power modules works in a PWM (pulse-width modulation) mode, and the rest N-1 power modules work in a through mode. The power module working in the PWM mode works in a circulation mode; and determining the input sequence of the power modules in the direct-through mode according to the statistical time length of the previous time period. The method can greatly reduce the switching times of the power device, and the temperature fluctuation of the power device is smoother, thereby prolonging the service life of the device.)

1. A cyclic control method of a modular track traffic resistance braking energy absorption device is characterized in that the track traffic regenerative energy absorption device comprises N power modules, and the total power of the N power modules is matched with the braking power of train braking; selecting 1 power module from the N power modules to work in a PWM mode, and the rest N-1 power modules to work in a direct-through mode;

and selecting the power module in the PWM mode or the through mode to be put into or out of work according to the braking power required by the train braking.

2. The cyclic control method of the modular rail transit resistive braking energy absorption device according to claim 1, wherein the step of selecting the power module in the PWM mode or the through mode to be put into or taken out of operation according to the braking power required by train braking comprises the steps of:

when the braking power of the train gradually rises, the power module in the PWM mode is firstly put into operation, and then the power module in the 1 st through mode starts to work until all the power modules in the through modes are put into operation.

3. The cyclic control method of the modular rail transit resistive braking energy absorption device according to claim 2, wherein the putting into operation of the power module in the through mode comprises:

the through mode power module steps up the modulation ratio to 1 for operation.

4. The cyclic control method of the modular rail transit resistive braking energy absorption device according to claim 1, wherein the step of selecting the power module in the PWM mode or the through mode to be put into or taken out of operation according to the braking power required by train braking comprises the steps of:

when the braking power of the train is gradually reduced, the power module in the (N-1) th through mode is quitted to work until all the power modules in the through mode quit to work, and finally the power module in the PWM mode quits.

5. The cyclic control method of the modular rail transit resistive braking energy absorption device according to claim 4, wherein the exit of the power module in the through mode comprises:

the through mode power module steps down the modulation ratio to 0 and exits the operation.

6. The cyclic control method of the modular rail transit resistive braking energy absorption device according to claim 1, wherein the power module in the PWM mode is put into operation in a cyclic mode.

7. The cyclic control method of the modular rail transit resistive braking energy absorption device according to claim 6, wherein the PWM-mode power module operating in a cyclic mode comprises:

performing cumulative statistics on the working time of N-1 direct-connection mode power modules in the last statistical time; and at the next statistical time, selecting the power module with the shortest working time in the direct-through mode at the last statistical time to work in the PWM mode.

8. The cyclic control method of the modular rail transit resistive braking energy absorption device according to claim 1, wherein the putting into operation of the power module in the through mode comprises:

and determining the input sequence of the direct-connection mode power module according to the statistical time length of the previous time period.

9. The cyclic control method of the modular rail transit resistive braking energy absorption device according to claim 8, wherein the step of determining the input sequence of the through-mode power modules according to the statistical duration of the previous period comprises:

carrying out accumulated statistics on the working time of the N-1 through mode power modules in the previous statistical time period, and sequencing the statistical time from short to long; and in the next statistical time period, the sequence of the input of the direct-through mode power modules is input to work according to the sequence of the statistical time from short to long in the last statistical time period.

10. The cyclic control method for the modular rail transit resistive braking energy absorption apparatus according to claim 9, wherein the statistical time interval of the pass-through mode power module is that the running time per day is listed divided by N "1, and the time interval is an integer.

Technical Field

The invention belongs to the technical field of control of a rail transit regenerative energy resistance absorption device, and particularly relates to a circulation control method of a modular rail transit resistive braking energy absorption device.

Background

When a subway train is braked, kinetic energy of the train is converted into electric energy, the electric energy is accumulated on a direct-current traction network to cause voltage rise of the traction network, and a track traffic regenerated energy resistance absorption device (hereinafter referred to as a device) is used for putting a resistor on the traction network in a certain control mode when the voltage rises and controlling the time of putting the resistor, so that the electric energy is consumed, the traction network voltage is stabilized, and a chopper and a resistor are generally arranged on the subway train. The device is moved to the ground, and the device has the advantages of reducing the weight of the vehicle, saving energy, reducing the temperature rise of the tunnel and the like.

The device is composed of power modules, brake resistors and a control system, each power module is a chopper, and each power module is connected with one brake resistor to form a branch circuit, as shown in a topological schematic diagram of the device shown in fig. 1. Under the conventional control mode, the power modules of the device simultaneously work in the PWM mode, as shown in FIG. 2. The PWM working mode is as follows: when the modulation ratio is 0, namely the output is 0 level, no voltage is applied to the brake resistor; when the modulation ratio is 1, a high level 1 is continuously output and a voltage is applied to the brake resistor. When the modulation ratio is 0.5, in the switching period T_sThe ratio of the time between the internal 0 and 1 levels is 1:1, i.e. half of the time during which voltage is applied to the resistor and half of the time during which no voltage is applied to the resistor. By changing the modulation ratio, the time when the voltage is applied to the brake resistor can be adjusted, thereby adjusting the power of the brake resistor, even if the power of the brake resistor is continuously and smoothly adjustable from 0 to full power. In this mode of operation, the power device is turned on and off once every time the level of the PWM changes from 0-1-0, i.e. for one switching period T_sThe power device operates frequently.

In the subway train station-entering braking process, the braking power fluctuates along with time according to the power shown in fig. 3. In the early stage of train braking, the braking power is increased along with time, and in order to maintain the voltage stability of a traction network, the power of an input resistor needs to be gradually increased from 0, namely the PWM (pulse width modulation) ratio of each power module is gradually increased from 0; in the middle braking period of the train, the braking power is basically maintained to be constant, the power of the input resistor needs to be maintained to be constant, and the PWM (pulse width modulation) ratio of each power module is basically constant; at the end of train braking, the braking power is reduced along with time, and the power of the input resistor needs to be reduced step by step, namely the PWM modulation ratio is reduced to 0 step by step. Meanwhile, the subway trains enter the station at certain time intervals, such as one train every 2 minutes in a peak period and one train every 5 minutes in a low peak period. Every time a train enters the station for braking, the power device of the device works according to the PWM mode, namely, the power device circularly changes according to the time interval of train entering. The power change is large in the braking process of the train, the PWM (pulse-width modulation) ratio of the power module changes violently, and meanwhile, the power device in the power module acts frequently, so that the temperature of the power device in the device fluctuates frequently, the fluctuation can accelerate the aging of the power device, and the whole service life of the device is shortened.

Disclosure of Invention

The invention aims to reduce the frequency of switching actions of a power device of a device in the prior art and reduce the temperature fluctuation of the power device, and provides a circulating control method of a modular track traffic resistance braking energy absorption device, which can greatly reduce the switching frequency of the power device, make the temperature fluctuation of the power device smooth and improve the service life of the power device of the device.

In order to solve the technical problem, the invention provides a cyclic control method of a modular track traffic resistance braking energy absorption device, which is characterized in that the track traffic regenerative energy resistance absorption device comprises N power modules, and the total power of the N power modules is matched with the braking power of train braking; selecting 1 power module from the N power modules to work in a PWM mode, and the rest N-1 power modules to work in a direct-through mode;

and selecting the power module in the PWM mode or the through mode to be put into or out of work according to the braking power required by the train braking.

Further, the step of selecting the power module in the PWM mode or the through mode to be put into or taken out of operation according to the braking power required by train braking includes:

when the braking power of the train gradually rises, the power module in the PWM mode is firstly put into operation, and then the power module in the 1 st through mode starts to work until all the power modules in the through modes are put into operation.

Further, the putting into operation of the through-mode power module includes:

the through mode power module steps up the modulation ratio to 1 for operation.

Further, the step of selecting the power module in the PWM mode or the through mode to be put into or taken out of operation according to the braking power required by train braking includes:

when the braking power of the train is gradually reduced, the power module in the (N-1) th through mode is quitted to work until all the power modules in the through mode quit to work, and finally the power module in the PWM mode quits.

Further, the exit from operation of the power module in the through mode includes:

the through mode power module steps down the modulation ratio to 0 and exits the operation.

Further, the power module in the PWM mode is put into operation in a cyclic mode.

Further, the operating of the power module in the PWM mode in the cyclic mode includes:

performing cumulative statistics on the working time of N-1 direct-connection mode power modules in the last statistical time; and at the next statistical time, selecting the power module with the shortest working time in the direct-through mode at the last statistical time to work in the PWM mode.

Further, the putting into operation of the through-mode power module includes:

and determining the input sequence of the direct-connection mode power module according to the statistical time length of the previous time period.

Further, the step of determining the input sequence of the through mode power module according to the statistical time duration of the previous time period includes:

carrying out accumulated statistics on the working time of the N-1 through mode power modules in the previous statistical time period, and sequencing the statistical time from short to long; and in the next statistical time period, the sequence of the input of the direct-through mode power modules is input to work according to the sequence of the statistical time from short to long in the last statistical time period.

Further, the statistical time interval of the through mode power module is to list the running time per day divided by N-1, and the time interval is an integer.

Compared with the prior art, the invention has the following beneficial effects: the method can greatly reduce the switching times of the power device, and the temperature fluctuation of the power device is smoother, thereby prolonging the service life of the device.

Drawings

FIG. 1 is a schematic diagram of a 4-branch modular device system;

FIG. 2 illustrates PWM waveforms of 4-branch modules under a conventional control method under operation of each power module;

FIG. 3 is a plot of power versus time under train braking;

FIG. 4 is a PWM waveform of each power module of the 4-branch module according to the control method of the present invention;

FIG. 5 is a waveform for a power module pass-through mode input;

fig. 6 is a waveform for the power module pass-through mode exit condition.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The invention conception of the invention is as follows: the method is based on a track traffic regenerative energy resistance absorption device platform, only 1 module of N power modules works in a PWM modulation mode, and the rest N-1 power modules work in a direct-through mode. The power module working in the PWM mode works in a circulation mode; and determining the input sequence of the power modules in the direct-through mode according to the statistical time length of the previous time period. When the power module is put into the direct-through mode, the modulation ratio is gradually increased to 1 by putting the direct-through power module into the direct-through mode; while the power module operating in the PWM mode steps down the modulation ratio to the appropriate value. Gradually reducing the modulation ratio to 0 when the power module exits the pass-through mode; while the power module operating in the PWM mode gradually increases the modulation ratio to an appropriate value. By the control method, the switching times of the power device can be greatly reduced, the temperature fluctuation of the power device is smoother, and the service life of the device is prolonged.

The invention provides a cycle control method of a modular rail transit resistive braking energy absorption device, which comprises the following steps:

the first step is as follows: the track traffic regenerated energy resistance absorption device is in a modular design and consists of N power modules. Each power module is connected with a brake resistor to form a branch circuit, and the rated power of each resistor is the same. The total power of the N resistors is matched with the power of train braking.

Assuming the train brake rated power is P₁The braking power is from 0 to P₁And (4) changing. Total power of the brake resistor is P₂(P₂>P₁The braking resistance power is provided with a certain margin), each resistance power is

The second step is that: and selecting 1 power module from the N power modules to work in a PWM modulation mode, and working the rest N-1 power modules in a through mode.

The power module can be also referred to as PWM mode power module for short when working in PWM modulation mode, and the PWM modulation mode (or referred to as PWM mode for short) means: PWM is a pulse width modulation technique, the modulation ratio of which is continuously adjustable from 0 to 1. When the modulation ratio is 0, namely the output is 0 level, the power module is switched off, and no voltage is applied to the brake resistor; when the modulation ratio is 1, the high level 1 is continuously output, the power module is switched on, and the voltage is applied to the brake resistor. When the modulation ratio is 0.5, in the switching period T_sThe ratio of the time between the internal 0 and 1 levels is 1:1, i.e. half of the time during which voltage is applied to the resistor and half of the time during which no voltage is applied to the resistor. By varying the modulation ratio, the time during which the voltage is applied to the braking resistor can be adjusted, thereby adjusting the power of the braking resistor, i.e. the resistance power goes from 0 to

And continuous smooth adjustment is realized.

The power module can also be referred to as a through-mode power module for short when it operates in a through-mode, said through-modeThe meaning of the mode is: the power module operates in a through mode with a modulation ratio of 0 or 1 and no intermediate values, i.e. with a resistance power of 0 or

And thirdly, selecting the corresponding power module to be put into or quit working by the device according to the braking power required by the current train braking.

When the train braking power rises, the power module in the PWM mode is firstly put into operation, then the power module in the 1 st through mode is put into operation until all the power modules in the through modes are put into operation, when the train braking power drops, the device starts to quit from the power module in the (N-1) th through mode until all the power modules in the through modes quit, and finally quits the power module in the PWM mode. The PWM waveforms of the individual power modules at a certain steady braking power are shown in fig. 4.

The specific working process is as follows:

when the braking power of the vehicle is gradually increased, the braking power is increased from 0 toIn the middle of the time, the power module in the PWM mode can be matched with the train braking power by gradually increasing the modulation ratio; when the modulation ratio approaches 1, the train braking power approaches

When the train brakes power fromRise to

When the power module in the 1 st through mode is required to work, the input power is close to that of the power module in the 1 st through mode when the power module in the 1 st through mode is directly input

When the train is larger than the current timeBraking powerThe traction direct current bus can be reduced violently, and the train operation is influenced. When the direct-through mode power module is switched in, the direct-through mode power module gradually increases the modulation ratio to 1 and enters a direct-through mode; while the power module operating in the PWM mode gradually reduces the modulation ratio to 0. Fig. 5 is a PWM waveform diagram of each power module when the 2 nd through power module is put into operation. As the train power increases, the power module modulation ratio operating in PWM mode continues to increase to match the train's braking power. By analogy, as the train braking power continues to increase, when the N-1 th straight-through mode power module is initially switched in, the train braking power reaches

The braking power of the train reaches P₁When the power of the power module in the working PWM mode reaches

When the vehicle braking power is from P₁When the modulation ratio is close to 0, namely the train braking power is close to 0

The power module in the (N-1) th direct-connection mode is required to exit the operation, so that the power module in the direct-connection mode directly exits the direct connection, and the input power is

Less than train braking powerThe train traction direct current bus can be severely raised, and the train operation is influenced. Therefore, when the through-mode power module exits, it is necessary for the through-mode power module to gradually decrease the modulation ratio to 0 until the through-mode power module exits from operationA row; while the power module operating in the PWM mode gradually increases the modulation ratio to 1. Fig. 6 is a PWM waveform diagram of each power module when the 2 nd through power module exits operation. As the train power continues to decrease, the power module modulation ratio operating in PWM mode continues to decrease from 1 to 0 to match the braking power of the train. By analogy, as the train braking power continues to decrease, when the 1 st straight-through mode power module finally quits operation, the train braking power reaches

And as the train braking power continues to be reduced until 0, the modulation ratio of the power module working in the PWM mode is reduced from 1 to 0, and finally the train stops and the device stops outputting.

The above-described step-up or step-down of the modulation ratio from 0 to 1 or from 1 to 0, emphasized when the through-mode power module is put in or out, is not a slow process as in the PWM mode. The stepwise adjustment from 0 to 1, from 1 to 0 described in the pass-through mode is a transition, being a short time process. As shown in the upper right of fig. 5 and 6, the time from 0 to 1, from 1 to 0 lasts for 0.05s, and the time is extremely short, and is negligible with respect to the time when the power module is at 0 or 1. The modulation ratio is gradually increased or decreased in the through mode to make the transition process from 0 to 1, 1 to 0 smoother and reduce the power impact when the through mode power module is directly put into or taken out of the power module.

And fourthly, the power module in the PWM mode works in a circulation mode.

If a certain power module works in the PWM mode for a long time, the temperature fluctuation of an internal power device is large, the power device can be aged more quickly, and the service life is shortened. Therefore, the power module in the PWM mode works in a circulation mode, the device selects one power module which works in the direct-through mode in the previous day to replace the power module which works in the PWM mode in the previous day every day, and the circulation is carried out once every N days. According to the running time of the subway train, the train is dispatched every 6 morning and is collected 24 evening. The statistical time interval can be counted according to the working time of the train, and is generally 1 day. The device carries out accumulated statistics on the working time of N-1 direct-connection mode power modules in the previous day; and on the next day, selecting the power module with the shortest working time in the direct-through mode on the previous day to work in the PWM mode.

Fifthly, the input sequence of the power modules in the direct-through mode is carried out according to the following method: carrying out accumulated statistics on the working time of the straight-through modes of the N-1 power modules in the previous statistical time period, and sequencing the statistical time from short to long; and (4) putting the power module in the next statistical time period into the direct-through mode according to the sequence of the statistical time in the previous statistical time period from short to long, and carrying out circular statistics. In order to ensure that the average heat generation of the power unit in the through mode is uniform every day as far as possible. The statistical time interval of the direct mode is the running time of the subway every day divided by N-1, and the time interval is an integer.

Taking a four-branch device as an example, the number of the power units in the direct-connection mode is 3, the subway operation time is 18 hours, namely, the power units are alternated every 6 hours; the first power module to be put through may cycle once a day. The power unit in the direct-current mode can be guaranteed to generate heat uniformly every day as far as possible.

For convenience of statistics, the power module is switched from the PWM mode to the through mode, and the initial statistical time length in the through mode is 0.