阅读说明：本技术 城市轨道交通牵引错峰填谷稳定回收储能供电量控制方法 (Method for controlling power supply quantity of stable recovery energy storage during urban rail transit traction peak shifting and valley filling ) 是由 梁波 马跃 詹跃东 蔡忠 李建祥 赵小波 鲁圣国 于 2021-09-14 设计创作，主要内容包括：本发明涉及一种城市轨道交通牵引错峰填谷稳定回收储能供电量控制方法,包括一个以上城市轨道交通牵引供电单元及控制每个城市轨道交通牵引供电单元工作的能量智能控制系统；特点是每个城市轨道交通牵引供电单元均包括牵引降压变电所、双向变流器、储能装置及双向变换器；其控制方法是：运行前的将准备工作,运行前能量智能控制系统的检测工作,以及能量智能控制系统检测轨道车辆是否工作运营。其减小了回馈的再生制动能量对接触网电压和需市电电网的冲击,改善了入网电能质量,由于储能装置只是用来吸收少部分能量,体积和成本都大大降低了。(The invention relates to a method for controlling the power supply quantity of urban rail transit traction, peak shifting, valley filling, stable recovery and energy storage, which comprises more than one urban rail transit traction power supply unit and an energy intelligent control system for controlling each urban rail transit traction power supply unit to work; the system is characterized in that each urban rail transit traction power supply unit comprises a traction step-down substation, a bidirectional converter, an energy storage device and a bidirectional converter; the control method comprises the following steps: the method comprises the steps of preparing before operation, detecting the energy intelligent control system before operation, and detecting whether the rail vehicle operates or not by the energy intelligent control system. The impact of the regenerative braking energy on the contact network voltage and the power grid needing the commercial power is reduced, the quality of the power energy entering the network is improved, and the size and the cost are greatly reduced because the energy storage device is only used for absorbing a small part of energy.)

1. A control method for stably recovering stored energy and supplying power for urban rail transit traction peak load shifting comprises more than one urban rail transit traction power supply unit and an energy intelligent control system for controlling each urban rail transit traction power supply unit to work; the urban rail transit traction power supply unit is characterized by comprising a traction step-down substation, a bidirectional converter, an energy storage device and a bidirectional converter, wherein the urban power grid provides alternating current for the traction step-down substation; the energy storage device supplies power to the contact net through the bidirectional converter, and the bidirectional converter can store electric quantity generated during braking of the vehicle and charging of the contact net in the energy storage device; the control method of the intelligent energy control system comprises the following steps:

step one will prepare the job before running

Before operation, setting a maximum voltage Va and a minimum voltage Vb of an urban power grid in an energy intelligent control system, setting a maximum voltage Vc and a minimum voltage Vd of a contact network in the energy intelligent control system, setting an upper limit value and a lower limit value of the capacity SOC of an energy storage device in the energy intelligent control system, setting a voltage upper limit value Ve and a voltage lower limit value Vf of each electric section contact network in the energy intelligent control system, and entering the next operation after the values are set in the energy intelligent control system;

step two detection work of energy intelligent control system before operation

1) When the system runs, the energy intelligent control system samples the voltage of the urban power grid; if the voltage of the urban power grid is between the maximum voltage value Va and the minimum voltage value Vb, the energy intelligent control system stops detecting, and the urban power grid supplies power to the traction voltage-reduction substation and starts to operate; if the voltage of the urban power grid exceeds the set maximum voltage Va and minimum voltage Vb, the intelligent energy control system samples the voltage of the contact network, if the voltage of the contact network is between the maximum voltage Vc and the minimum voltage Vd, the intelligent energy control system works normally, the intelligent energy control system stops detecting, and the urban power grid supplies power to the traction voltage reduction substation and starts to operate; if the voltage of the overhead line system exceeds the maximum voltage Vc and the minimum voltage Vd, carrying out the following 2) steps;

step three energy intelligent control system detects whether rail vehicle is in operation

1) If the system is operated, the energy intelligent control system controls each urban rail transit traction power supply unit to enable the urban power grid to charge the energy storage device through the traction step-down substation, the bidirectional converter and the bidirectional converter, so that the capacity SOC of the energy storage device reaches the upper limit value of the energy storage device, and if the capacity SOC of the energy storage device reaches the upper limit value of the energy storage device, the system returns to the first step to perform voltage sampling detection;

2) if not, the energy intelligent control system detects the voltage of each electric section overhead line system; firstly, if the voltage of each sectional contact network is greater than the voltage upper limit Ve, the sectional contact network charges an energy storage device; after charging, if the energy storage device capacity SOC of the energy storage device is equal to the upper limit value, feeding electricity to the urban power grid by the segmented overhead line system and returning to the first step; if the energy storage device capacity SOC of the energy storage device is smaller than the upper limit value of the energy storage device, returning to the step 2); if the voltage of each sectional overhead line system is smaller than the voltage lower limit Vf, each urban rail transit traction power supply unit supplies power to each overhead line system and returns to the first step; thirdly, if the voltage of the contact network of each subsection is larger than the voltage lower limit value Vf, (a) calculating the power of each rail vehicle of each subsection, and if the output power is larger than zero, returning to the first step; and (b) if the output power is equal to zero, discharging the energy storage device of the section, returning to the step (I) when the capacity SOC of the energy storage device is equal to the lower limit value of the energy storage device, and returning to the step (a) for calculating the power of each rail vehicle of each section when the capacity SOC of the energy storage device is greater than the lower limit value of the energy storage device.

Technical Field

The invention relates to a method for controlling the power supply quantity of urban rail transit traction, peak shifting, valley filling and stable recovery of stored energy.

Background

At present, 750V or 1500V direct current power supply systems are mainly adopted in urban rail transit in China. The rail transit power supply system adopts a multi-pulse irreversible phase control rectification mode, so that the output characteristic is soft. When the rail transit vehicles are too many and in a traction state, the bus voltage of the power supply system can be greatly reduced. In addition, in the braking process of the urban rail transit vehicle, energy has the characteristics of high amplitude, short time and large power impact, and regenerative braking including resistance energy consumption braking, capacitance energy storage braking and inversion feedback braking is preferentially adopted. And when the electric brake can not meet the braking requirement, modes such as mechanical brake, air brake and the like are added. When the vehicle is in a braking state, the bus voltage of the power supply system is greatly increased, so that the urban rail transit vehicle mostly adopts a French mode, namely: regenerative braking + resistive braking, or german mode: regenerative braking + shaft disc braking + modern eddy current braking to restrain the rising of bus voltage, will improve the cost of vehicle like this, increase the maintenance step of vehicle, be unfavorable for driving safety, also greatly reduced to passenger's travelling comfort.

The locomotive enters a station to be braked, a motor of the locomotive reversely generates electricity to brake a vehicle to continue to operate, the voltage of a contact network connected with the locomotive can rise and even exceed a set upper limit value in the process, and in order to ensure that the voltage of a power grid is controlled within a certain safety range, the voltage of the contact network rises and cannot influence the power grid, a track traffic system generally absorbs electric energy in a mode of resistance energy consumption, super capacitor absorption or energy feedback to the power grid, so that the voltage of the power grid is maintained within the specified voltage value range. In these methods, the absorbed electrical energy is limited by the use because it cannot be stored, or is simultaneously inverted and fed back to the internet; or the power supply is provided for the outbound locomotive, and the absorbed electric energy cannot be absorbed and stored. And when the locomotive is frequently started at intervals of 2min, the absorption system cannot continuously work, and the balance of the grid voltage is influenced.

When a locomotive is braked when entering a station, the motor reversely rotates to generate electricity so that the voltage of a contact power grid is increased and even exceeds the upper limit of the voltage of a traction power grid, and the common solution is as follows: the resistance energy consumption device can effectively absorb energy, maintain the voltage balance of the power grid and protect the electric equipment in the electric system from being damaged; when in use, a large amount of heat is generated in a resistance energy consumption device, a station and a tunnel, and environment-control equipment such as an air conditioner, ventilation and the like is required to be configured for heat dissipation; the inversion feedback system is adopted to absorb the energy of the voltage rising part of the traction power grid, and then the energy is converted into an alternating current power supply through DC/AC, and the alternating current power supply is directly transmitted to the commercial power grid. The harmonic waves have impact on a mains supply power grid, so that a power grid company is difficult to solve; energy can be stored by using a flywheel, a super capacitor and the like, but the energy storage cannot be applied to commercialization due to high manufacturing cost and complex technology. Meanwhile, the ground braking resistor absorption devices are adopted in a few track lines using the energy absorption devices, although the energy generated during braking of the subway vehicles is absorbed, the braking energy is completely converted into heat energy by the braking resistors, so that energy is not really saved, and the energy is not beneficial to returning to green and energy-saving of the rail transit vehicles.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a method for controlling the traction, peak load shifting, stable recovery, energy storage and power supply quantity of urban rail transit, reduce the impact of the regenerative braking energy on the voltage of a contact network and a power grid needing commercial power, improve the quality of power energy of the network, and greatly reduce the volume and the cost because an energy storage device is only used for absorbing a small part of energy.

In order to achieve the purpose, the invention is realized in such a way that the method is a method for controlling the power supply quantity of the urban rail transit traction, peak load shifting, stable recovery and energy storage, and comprises more than one urban rail transit traction power supply unit and an energy intelligent control system for controlling each urban rail transit traction power supply unit to work; the urban rail transit traction power supply unit is characterized by comprising a traction step-down substation, a bidirectional converter, an energy storage device and a bidirectional converter, wherein the urban power grid provides alternating current for the traction step-down substation; the energy storage device supplies power to the contact net through the bidirectional converter, and the bidirectional converter can store electric quantity generated during braking of the vehicle and charging of the contact net in the energy storage device; the control method of the intelligent energy control system comprises the following steps:

step one will prepare the job before running

Before operation, setting a maximum voltage Va and a minimum voltage Vb of an urban power grid in an energy intelligent control system, setting a maximum voltage Vc and a minimum voltage Vd of a contact network in the energy intelligent control system, setting an upper limit value and a lower limit value of the capacity SOC of an energy storage device in the energy intelligent control system, setting a voltage upper limit value Ve and a voltage lower limit value Vf of each electric section contact network in the energy intelligent control system, and entering the next operation after the values are set in the energy intelligent control system;

step two detection work of energy intelligent control system before operation

1) When the system runs, the energy intelligent control system samples the voltage of the urban power grid; if the voltage of the urban power grid is between the maximum voltage value Va and the minimum voltage value Vb, the energy intelligent control system stops detecting, and the urban power grid supplies power to the traction voltage-reduction substation and starts to operate; if the voltage of the urban power grid exceeds the set maximum voltage Va and minimum voltage Vb, the intelligent energy control system samples the voltage of the contact network, if the voltage of the contact network is between the maximum voltage Vc and the minimum voltage Vd, the intelligent energy control system works normally, the intelligent energy control system stops detecting, and the urban power grid supplies power to the traction voltage reduction substation and starts to operate; if the voltage of the overhead line system exceeds the maximum voltage Vc and the minimum voltage Vd, carrying out the following 2) steps;

step three energy intelligent control system detects whether rail vehicle is in operation

1) If the system is operated, the energy intelligent control system controls each urban rail transit traction power supply unit to enable the urban power grid to charge the energy storage device through the traction step-down substation, the bidirectional converter and the bidirectional converter, so that the capacity SOC of the energy storage device reaches the upper limit value of the energy storage device, and if the capacity SOC of the energy storage device reaches the upper limit value of the energy storage device, the system returns to the first step to perform voltage sampling detection;

2) if not, the energy intelligent control system detects the voltage of each electric section overhead line system; firstly, if the voltage of each sectional contact network is greater than the voltage upper limit Ve, the sectional contact network charges an energy storage device; after charging, if the energy storage device capacity SOC of the energy storage device is equal to the upper limit value, feeding electricity to the urban power grid by the segmented overhead line system and returning to the first step; if the electric quantity of the energy storage device is smaller than the upper limit value Ca, returning to the step 2); if the voltage of each sectional overhead line system is smaller than the voltage lower limit Vf, each urban rail transit traction power supply unit supplies power to each overhead line system and returns to the first step; thirdly, if the voltage of the contact network of each subsection is larger than the voltage lower limit value Vf, (a) calculating the power of each rail vehicle of each subsection, and if the output power is larger than zero, returning to the first step; and (b) if the output power is equal to zero, discharging the energy storage device of the section, returning to the step (I) when the capacity SOC of the energy storage device is equal to the lower limit value of the energy storage device, and returning to the step (a) for calculating the power of each rail vehicle of each section when the capacity SOC of the energy storage device is greater than the lower limit value of the energy storage device.

Compared with the prior art, the invention has the following advantages:

1. the designed urban rail transit traction power supply system has the advantages of high speed, high efficiency, large capacity and strong anti-interference capability in storing and absorbing electric energy.

2. The designed bidirectional converter has the advantages of input power factor correction, low switching frequency, small switching loss, good electromagnetic compatibility, less input harmonic, low total harmonic content, small filter size and the like.

3. The locomotive brakes and pulls the power grid to boost or reduce voltage for over-limit, the energy intelligent management system can charge or supply power and stabilize voltage, peak impact caused by over-limit voltage on the power grid is restrained, harmonic influence is restrained, and therefore the power quality is improved.

4. When the voltage of a power supply bus of the traction power grid is higher than a preset range, the voltage is converted into the rated voltage of the energy storage device to charge the storage battery under the control of the energy intelligent management system, and the electric energy is stored in the energy storage unit.

5. When the voltage of the power supply bus of the traction power grid is lower than a preset range, the voltage is converted into the voltage within the preset range under the control of the energy intelligent management system, the storage battery discharges outwards to supply power to the power supply bus, and the voltage balance of the power supply bus is maintained.

6. The intelligent energy management system solves the use problem of absorbed electric energy, and can convert the electric energy into current and voltage according to the requirement to be used as other locomotives or other equipment of a station house.

7. The storage battery can be used as a backup power supply under the condition that the commercial power grid loses power, so that the locomotive can be ensured to run nearby or in a short period, and the running efficiency is improved; other equipment such as a station room and the like can be used as a backup power supply, so that the safety and the order stability of passengers are ensured.

8. The provided urban rail transit traction power supply system adopts the bidirectional converter to feed the regenerative braking energy back to the power grid, so that the energy is saved, the voltage of the direct-current power grid is stabilized, the safe and efficient operation of the vehicle is ensured, and meanwhile, the bidirectional converter has the advantages of low loss, high efficiency, low harmonic pollution to the input power grid, input power factor correction and the like.

9. The regenerative braking energy absorption scheme combining energy feed and energy storage is adopted, energy reasonable processing and energy distribution management technology is adopted, and energy feed and energy storage system complementation is adopted, so that the optimal power quality of the power grid is improved under the conditions of minimum equipment capacity and minimum equipment investment.

10. The rapid pulse energy buffering technology is adopted to realize the cooperation with an energy feedback type power supply system, reduce the impact of the pulse braking energy on an alternating current power grid, reduce alternating current harmonic current and alternating current voltage flicker, and simultaneously reduce the design capacity of a power supply converter.

11. According to the urban rail transit traction power supply system, the energy storage device is adopted to absorb redundant regenerative braking energy, the voltage of a direct-current power grid can be inhibited from rising, the stored energy is released at the moment of accelerating and starting of a vehicle, voltage support can be provided for a contact network (rail), the voltage drop amplitude of the contact network (rail) is prevented from being too large, and meanwhile the absorbed energy is effectively utilized. The stored energy released when the maximum load of a contact network (rail) occurs can also play a role in peak clipping and valley filling, so that the power capacity of the traction bidirectional converter can be properly reduced, and the energy transmission loss is reduced. The contact net (rail) has a voltage supporting effect, so that the power supply quality of the contact net (rail) is improved, and the traction performance of the rail transit vehicle is improved. In addition, when the power supply system is powered off, the energy storage device can also provide energy backup, and the support system can operate for a period of time in an emergency.

12. According to the provided urban rail transit traction power supply system, when the urban vehicles stop operating at 0-6 hours at night, namely the electricity consumption of a mains supply grid is low peak, the energy storage device can be charged through the bidirectional converter and the bidirectional converter, and the function of 'shifting peaks and filling valleys' is achieved. According to an intelligent energy scheduling algorithm in the peak shaving energy storage device, the energy storage device performs compensation power supply on a mains supply power grid through the bidirectional converter in the power utilization peak period of the mains supply power grid, and the overall capacity of the mains supply power grid can be improved by 20% -30% in a mode of charging the energy storage device in the power utilization valley period, so that the power utilization peak period of the mains supply power grid is adjusted, and electric energy is enabled to generate higher value.

Drawings

FIG. 1 is a control block diagram of the present invention;

fig. 2 is a control flow chart of the energy intelligent control system of the invention.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 1, the method for controlling the power supply amount of the urban rail transit traction, peak shifting, valley filling, stable recovery of stored energy and power supply includes more than one urban rail transit traction power supply unit and an energy intelligent control system for controlling the operation of each urban rail transit traction power supply unit; each urban rail transit traction power supply unit comprises a traction voltage-reduction substation, a bidirectional converter, an energy storage device and a bidirectional converter, wherein the urban power grid provides alternating current for the traction voltage-reduction substation, the bidirectional converter receives the reduced alternating current output by the traction voltage-reduction substation and supplies power to a contact network, and the bidirectional converter can input electric quantity generated when a vehicle is braked into the urban power grid through the traction voltage-reduction substation; the energy storage device supplies power to the contact net through the bidirectional converter, and the bidirectional converter can store electric quantity generated during braking of the vehicle and charging of the contact net in the energy storage device.

As shown in fig. 2, the control method of the intelligent energy control system is as follows:

step one will prepare the job before running

Before operation, setting a maximum voltage Va and a minimum voltage Vb of an urban power grid in an energy intelligent control system, setting a maximum voltage Vc and a minimum voltage Vd of a contact network in the energy intelligent control system, setting an upper limit value and a lower limit value of the capacity SOC of an energy storage device in the energy intelligent control system, setting a voltage upper limit value Ve and a voltage lower limit value Vf of each electric section contact network in the energy intelligent control system, and entering the next operation after the values are set in the energy intelligent control system; in this embodiment, the maximum voltage Va is 2000V, the minimum voltage Vb is 800V, the upper voltage Ve is 1800V, the lower voltage Vf is 1000V, the upper limit of the energy storage device capacity SOC is 0.95-1, and the lower limit of the energy storage device capacity SOC is 0-0.2.

Step two detection work of energy intelligent control system before operation

1) When the system runs, the energy intelligent control system samples the voltage of the urban power grid; if the voltage of the urban power grid is between the maximum voltage value Va and the minimum voltage value Vb, the energy intelligent control system stops detecting, and the urban power grid supplies power to the traction voltage-reduction substation and starts to operate; if the voltage of the urban power grid exceeds the set maximum voltage Va and minimum voltage Vb, the intelligent energy control system samples the voltage of the contact network, if the voltage of the contact network is between the maximum voltage Vc and the minimum voltage Vd, the intelligent energy control system works normally, the intelligent energy control system stops detecting, and the urban power grid supplies power to the traction voltage reduction substation and starts to operate; if the voltage of the overhead line system exceeds the maximum voltage Vc and the minimum voltage Vd, carrying out the following 2) steps;

step three energy intelligent control system detects whether rail vehicle is in operation

1) If the system is operated, the energy intelligent control system controls each urban rail transit traction power supply unit to enable the urban power grid to charge the energy storage device through the traction step-down substation, the bidirectional converter and the bidirectional converter, so that the capacity SOC of the energy storage device reaches the upper limit value of the energy storage device, and if the capacity SOC of the energy storage device reaches the upper limit value of the energy storage device, the system returns to the first step to perform voltage sampling detection;

2) if not, the energy intelligent control system detects the voltage of each electric section overhead line system; firstly, if the voltage of each sectional contact network is greater than the voltage upper limit Ve, the sectional contact network charges an energy storage device; after charging, if the electric quantity of the energy storage device is equal to the upper limit value Ca, feeding electricity to the urban power grid by the segmented overhead line system and returning to the first step; if the SOC of the energy storage device is smaller than the upper limit value, returning to the step 2); if the voltage of each sectional overhead line system is smaller than the voltage lower limit Vf, each urban rail transit traction power supply unit supplies power to each overhead line system and returns to the first step; thirdly, if the voltage of the contact network of each subsection is larger than the voltage lower limit value Vf, (a) calculating the power of each rail vehicle of each subsection, and if the output power is larger than zero, returning to the first step; and (b) if the output power is equal to zero, discharging the energy storage device of the section, returning to the step (I) when the capacity SOC of the energy storage device is equal to the lower limit value of the energy storage device, and returning to the step (a) for calculating the power of each rail vehicle of each section when the capacity SOC of the energy storage device is greater than the lower limit value of the energy storage device.

The intelligent energy management model of the power supply system comprises the following steps:

（1）

in the formula, the load power consumed by the contact network is shown; is the traction power of the rail vehicle; power generated for braking of the rail vehicle; the loss power of the contact net; for the power generated by the traction substation, the front symbol is +, which means that the bidirectional converter provided by the traction substation provides power and energy for a contact network, and the front symbol is-means that the contact network provides the bidirectional converter for feeding to a commercial power grid; for the power capacity of the energy storage device, the former symbol is + to indicate that the energy storage device provides a bidirectional converter to discharge to a contact network, and the former symbol is-to indicate that the contact network (rail) provides the bidirectional converter to charge to the energy storage device.

The energy feedback and energy storage combined traction power supply system is adopted, when a vehicle is started and pulled, the traction bidirectional converter outputs main power supply, and the energy storage device outputs auxiliary energy to prepare for absorbing energy during the next braking; when a vehicle is braked, most energy can be fed back to a power grid through the reversible traction bidirectional converter, and the energy storage device is only used for absorbing a small amount of redundant braking energy through the bidirectional converter, so that the reversible traction bidirectional converter can be designed according to the maximum rectifying power instead of the maximum energy feeding power, the configuration capacity of the traction bidirectional converter can be reduced, and the capacity utilization rate of the traction bidirectional converter is improved. Due to the participation of the energy storage device, the impact of the regenerative braking energy on the contact network (rail) voltage and the commercial power grid can be reduced, and the network access electric energy quality is improved. In addition, because the energy storage device is only used for absorbing a small part of energy, the volume and the cost can be greatly reduced.

The invention provides an intelligent management method for urban rail transit traction peak shifting, valley filling, stable absorption, energy storage and power supply energy. When the rail transit vehicle is in a traction state, the bus voltage of the power supply system can be greatly reduced, and the energy intelligent management system supplies power to the rail transit vehicle through the storage battery pack and the double-converter auxiliary traction voltage-reduction substation and the rectifier, so that the bus voltage of the power supply system is ensured to be stabilized in a required range. When the rail transit vehicle is in a braking state, the power supply system causes the voltage of a contact power grid to be increased, and the energy intelligent management system charges the storage battery through the double converters by using the energy generated by the rail transit vehicle so as to supplement the energy lost when the storage battery is discharged. If the storage battery is charged to the required energy value through the double converters when the rail transit vehicle is in a braking state, the energy intelligent management system feeds back energy generated when the rail transit vehicle is braked to the power grid through the inverter. When the rail transit vehicle stops running at night, the energy intelligent management system charges the storage battery through the traction voltage-reduction substation and the rectifier, and the purpose of staggering peaks and filling valleys is achieved.

The embodiments of the present invention are described in detail above with reference to the drawings, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention.