CN115714436A - Stable power supply method of multi-energy storage power supply system suitable for traffic system - Google Patents
Stable power supply method of multi-energy storage power supply system suitable for traffic system Download PDFInfo
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Abstract
The invention relates to a stable power supply method of a multi-energy storage power supply system suitable for a traffic system, which is characterized in that a multi-energy power supply network framework is constructed according to the distribution characteristics of road traffic load, a micro-grid system consisting of wind energy, light energy, an energy storage battery and a super capacitor is introduced as power supply supplement of a large power grid, and a UPS and a diesel power generation system are introduced as emergency power supply guarantee; in the aspect of a system control strategy, the particularity of road traffic load is fully considered from two aspects of microgrid converter control and system comprehensive control, and the stable operation of a microgrid system is ensured; in the aspect of source and load coordination control, on the premise of ensuring stable power supply of road traffic load, the factors such as comprehensive and efficient utilization of energy, power utilization cost and the like are considered, and the system is ensured to work in an optimal mode state.
Description
Technical Field
The invention relates to the technical field of road traffic load energy guarantee, in particular to a stable power supply method of a multi-energy storage power supply system suitable for a traffic system.
Background
The road traffic load is mainly power load, but has many new characteristics that the traditional power load does not have, wherein the impact and the fluctuation performance are most obvious. The highway system in China has the inherent properties of long total mileage and obvious regional characteristics, roads in different regions are in different natural environments, and the types of energy sources capable of being utilized are different. In recent years, the rapid development of new energy vehicles mainly including electric vehicles has prompted the highway infrastructure to advance rapidly towards the direction of electromotion and intellectualization, and the premise of electromotion and intellectualization is that a set of stable and efficient power guarantee system, a new guarantee mode, load characteristics, protection requirements and the like have new requirements for a highway traffic load power supply system.
The highway is characterized by strip-shaped distribution, the energy demand of the highway is determined to be also in strip-shaped distribution, and the highway also has the point-oriented centralized characteristic in areas such as a service area, a rest area and the like, the power grid conditions of the highway are different along with the extension of the highway to all over the country, and in order to ensure the power supply of important point guarantee objects such as the service area, a tunnel and the like, the current solution is mostly guaranteed in a special line erection mode, and the system construction cost is high; meanwhile, a single power supply line has the conditions of poor power supply quality, unstable power supply and the like, and a new thought needs to be adopted for planning and constructing the highway energy guarantee.
The new energy provides a brand-new solution for traffic energy guarantee, can realize on-site conversion and on-site utilization, saves construction cost rise and energy loss caused by long-distance line erection, is green and environment-friendly, and has no pollution to the environment. However, the new energy sources are various in types and uneven in capacity distribution, and also have the problems of uneven space-time distribution, fluctuation and the like, the new energy sources are simply used as power supply guarantee of road traffic loads, and the stability of the new energy sources is possibly inferior to that of a traditional power grid.
Disclosure of Invention
The invention discloses a stable power supply method of a multi-energy storage power supply system suitable for a traffic system, which is characterized in that the multi-energy storage power supply system is constructed by fully utilizing various energy sources such as a traditional power grid, a new energy micro-power grid, a UPS (uninterruptible power supply) and a diesel power generation system, and the difficult problem of poor stability of a road traffic load energy power supply system can be perfectly solved by mutually networking and combining unified control.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a stable power supply method of a multi-energy storage power supply system suitable for a traffic system comprises the following steps:
constructing a multi-energy storage power supply system, wherein the multi-energy storage power supply system comprises a large power grid, a micro-grid system, a UPS (uninterrupted power supply), a diesel power generation system and an energy management system for controlling dispatching, wherein the large power grid, the micro-grid system, the UPS and the diesel power generation system can independently supply power to a load bus special for highway traffic; the micro-grid system comprises a photovoltaic power generation assembly, a wind power generation assembly and an energy storage system consisting of an energy storage battery and a super capacitor, wherein an alternating current bus and a direct current bus are arranged in the micro-grid system, the alternating current bus is respectively connected with a large power grid and a highway traffic dedicated load bus, the direct current bus is respectively connected with a light energy conversion module, an energy storage battery conversion module, a super capacitor conversion module and a wind energy conversion module, an inversion module is connected between the direct current bus and the alternating current bus, and a comprehensive control module in the micro-grid system receives a scheduling instruction of an energy management system and controls the micro-grid system to operate;
the stable power supply method of the multi-energy storage power supply system comprises bus voltage stabilization control and source-charge coordination control;
when the micro-grid system operates in a grid-connected mode, in a source-load coordination control mode, a load bus special for road traffic is supplied with power by a large power grid and the micro-grid system; in a bus voltage stabilization control mode, under the scheduling of an integrated control module, at the same moment, at least two modules of an inverter module, an energy storage battery conversion module and a super capacitor conversion module operate in a direct current bus voltage stabilization control mode, wherein the inverter module is switched between the direct current bus voltage stabilization control mode and an alternating current bus droop control mode, and the energy storage battery conversion module and the super capacitor conversion module are respectively switched between the direct current bus voltage stabilization control mode and a charging and discharging control mode;
when little grid system operates in off-grid mode, the integrated control module is based on energy storage system's electric quantity and photovoltaic power generation and wind power generation's the condition of exerting oneself and is controlled, wherein, among the source load coordinated control mode, the priority order for highway traffic load power supply does in proper order: microgrid system, UPS, diesel generating system; in the bus voltage stabilization control mode, the inverter module works in an alternating current bus voltage stabilization control mode, and at least one of the energy storage battery conversion module and the super capacitor conversion module operates in a direct current bus voltage stabilization control mode at the same time.
Further, in the off-grid mode, the source load coordination control method specifically comprises the following steps:
firstly, starting an energy storage system to supply power to a load bus special for highway traffic, monitoring the electric quantity of the energy storage system in real time by a comprehensive control module, starting a photovoltaic power generation assembly to charge the energy storage system by the comprehensive control module when the electric quantity of the energy storage system is reduced to a first threshold value, and stopping a power generation mode by the photovoltaic power generation assembly when the electric quantity of the energy storage system is increased to a fifth threshold value;
when the electric quantity of the energy storage system continuously drops to a second threshold value, the comprehensive control module starts the wind power generation assembly to charge the energy storage system, and when the electric quantity of the energy storage system is higher than the second threshold value, the wind power generation assembly exits a power generation mode;
when the electric quantity of the energy storage system continuously drops to a third threshold value, the road traffic non-important load is cut off, the UPS is started to independently supply power to the important load, when the electric quantity of the energy storage system rises to a sixth threshold value, the UPS is stopped to supply power, the road traffic non-important load is closed again, and the micro-grid system supplies power again; when the electric quantity of the UPS is reduced to a fourth threshold value, the diesel power generation system is started to supply power to the load bus special for highway traffic, and when the electric quantity of the energy storage system is increased back to a sixth threshold value, the diesel power generation system is stopped to generate power and the micro-grid system supplies power again;
in the above threshold values, the following are sequentially performed from large to small: a fifth threshold, a first threshold, a sixth threshold, a second threshold, and a third threshold.
Further, the first threshold is 70% of the capacity of the energy storage system, the second threshold is 40% of the capacity of the energy storage system, the third threshold is 10% of the capacity of the energy storage system, the fifth threshold is 95% of the capacity of the energy storage system, the sixth threshold is 50% of the capacity of the energy storage system, and the fourth threshold is 10% of the capacity of the UPS.
Further, the wind power generation module is set to have a hysteresis control amount of 5% when exiting or entering.
Further, in a grid-connected mode, the bus voltage stabilization control method specifically comprises the following steps:
the control mode of the energy storage battery conversion module is determined as follows:
step 1: firstly, judging whether the energy storage battery needs to be subjected to charge and discharge management, if not, operating in a direct-current bus voltage stabilization control mode, and if so, continuing the judgment of the step 2;
and 2, step: synchronously judging whether the inversion module and the super capacitor conversion module operate in a direct current bus voltage stabilization control mode or not, and if so, determining the energy storage battery conversion module as a charge and discharge control mode; if only one of the inversion module and the super capacitor conversion module operates in the direct current bus voltage stabilization control mode, the energy storage battery conversion module is determined to be in the direct current bus voltage stabilization control mode;
the control mode of the super capacitor conversion module is determined as follows:
and step 3: firstly, judging whether the amplitude of the voltage drop of the direct current bus exceeds a set seventh threshold, if so, operating in a direct current bus voltage stabilization control mode, and if not, continuing the judgment of the step 4;
and 4, step 4: judging whether the super capacitor needs to be subjected to charge and discharge management, if not, operating the super capacitor conversion module in a direct current bus voltage stabilization control mode, and if so, continuing the judgment of the step 5;
and 5: synchronously judging whether the inversion module and the energy storage battery conversion module operate in a direct current bus voltage stabilization control mode, if so, determining the super capacitor conversion module as a charge and discharge control mode; if only one of the inversion module and the energy storage battery conversion module operates in the direct-current bus voltage stabilization control mode, the super capacitor conversion module is determined to be in the direct-current bus voltage stabilization control mode;
the control mode of the inverter module is determined as follows:
step 6: synchronously judging whether the super capacitor conversion module and the energy storage battery conversion module operate in a direct current bus voltage stabilization control mode, if so, continuing the judgment of the step 7, and if only one of the super capacitor conversion module and the energy storage battery conversion module operates in the direct current bus voltage stabilization control mode, determining the inversion module as the direct current bus voltage stabilization control mode;
and 7: judging whether the integrated control module reaches the control instruction of the droop mode of the alternating-current bus or not, if so, judging whether the integrated control module reaches the control instruction of the droop mode of the alternating-current bus or not
If the control mode is not the droop control mode, the inversion module determines the voltage stabilization control mode of the direct current bus.
Further, the reduction amplitude of the dc bus voltage refers to a difference between the dc bus voltage collected at the current time and the dc bus voltage collected at the previous time, the seventh threshold is a dc bus voltage reduction rate, and the reduction rate is set to 15%.
Aiming at a power supply system constructed by multi-energy storage, the invention adopts four-stage power supply guarantee of a large power grid, a new energy micro-power grid, a UPS and a diesel power generation system, and can improve the power supply stability of road traffic load to the maximum extent by matching with a multi-bus stable control strategy.
Drawings
Fig. 1 is a schematic diagram of a network architecture of a multi-energy-source energy-storage power supply system in an embodiment.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
The embodiment discloses a multi-energy storage power supply system suitable for a traffic system and a stable power supply method of the power supply system, and with reference to fig. 1, a multi-energy storage power supply system is firstly constructed, four levels, namely a large power grid, a micro-grid system, a UPS and a diesel power generation system, are set for power supply guarantee of the multi-energy storage power supply system, and power supply priority orders of the four levels of power supply guarantee are different. The large power grid is used as a main source of electricity used by traffic loads, and when the micro-grid system is operated in a grid-connected mode, the micro-grid system supplies electricity for the traffic loads by means of photovoltaic power generation and wind power generation. The UPS is used as energy supplement for a large power grid and a micro-grid system, and when the large power grid and the micro-grid system simultaneously break down, the UPS is started to supply power for important loads of road traffic. The UPS can also compensate the condition of short-time voltage interruption of the micro-grid system in the operation mode switching process. The diesel power generation system is used as an emergency backup power supply, and when the electric quantity of the UPS is insufficient to support load power consumption, the diesel power generation system is started to supply power to important loads.
Four energy sources of photovoltaic power generation, energy storage batteries, super capacitors and wind power generation are arranged in the micro-grid system, the energy storage batteries and the super capacitors form an energy storage system in the micro-grid system, and the photovoltaic power generation and the wind power generation form a new energy power generation system in the micro-grid system. A high-voltage direct-current bus and a high-voltage alternating-current bus are arranged in the microgrid system, the photovoltaic power generation assembly is connected with the direct-current bus through a light energy conversion module, the energy storage battery is connected with the direct-current bus through an energy storage battery conversion module, the super capacitor is connected with the direct-current bus through a super capacitor conversion module, and the wind power generation assembly is connected with the direct-current bus through a wind energy conversion module. The alternating current bus is connected with the direct current bus through the inversion module. Each device in the micro-grid system is connected with the comprehensive control module through a communication line and receives the unified scheduling management of the comprehensive control module. The comprehensive control module is an operation control center of the micro-grid system, receives real-time operation data of each module device, is connected with an external energy management system through a communication line, and receives a scheduling instruction of the energy management system.
An alternating current bus in the micro-grid system is connected with a large power grid through a switch K1 and an isolation transformer 1, and the alternating current bus in the micro-grid system is also connected with a special load bus for road traffic through a switch K2 and an isolation transformer 2. The UPS and the diesel power generation system are respectively connected with the comprehensive control module through communication lines, and the UPS and the diesel power generation system are also respectively connected with the energy management system through the communication lines. The UPS is connected with the special load bus for road traffic through a switch K8, and the diesel power generation system is connected with the special load bus for road traffic through a switch K9. The highway traffic special load mainly comprises a road monitoring charging system, a direct current charging pile, an alternating current charging pile, novel heat load equipment, other alternating current loads and the like, wherein the power loads are connected to a highway traffic special load bus through switches K3-K7 respectively.
The internal control algorithm of the comprehensive control module is divided into three levels, wherein the first level receives a dispatching instruction of a superior system, performs preliminary acceptance confirmation on the dispatching instruction, and generates a total operation mode and an operation strategy of the micro-grid system, so that the switches K1 and K2 are controlled to be closed or opened to adapt to the current external power grid state and the control instruction; the second level is that after the overall operation mode and the operation strategy of the microgrid system are confirmed, the specific operation modes and operation scheduling instructions of the four modules are generated and issued through an internal photovoltaic conversion module control algorithm, an energy storage battery conversion module control algorithm, a super capacitor module control algorithm and a wind energy conversion module control algorithm, and the four modules are controlled to operate in a correct and reasonable operation mode; and the third level is to confirm the operation mode and the operation strategy of the inversion module, the level needs to analyze the operation feedback data of the module, and carries out comprehensive calculation according to the control algorithm in the inversion module by combining the currently acquired external power grid characteristic information and the load characteristic information of the highway traffic special load to generate the operation control instruction of the inversion module so as to ensure the load adaptation and the stable operation of the whole system.
In the power supply system, the energy storage battery plays roles in energy storage and direct-current bus voltage stabilization in the system; wind power generation and photovoltaic power generation are unstable new energy, wherein the photovoltaic power generation has remarkable time distribution characteristics, and cannot generate power at night. Wind power generation is different from photovoltaic power generation, and although power generation can be realized at night, the fluctuation is obvious and is not limited by load requirements, and the wind power generation cannot be used as a stable energy source to supply road traffic loads. The energy storage battery system plays a role of an energy buffer pool, the control strategy of the energy storage system in the invention is different according to different system operation modes, the energy storage system receives the dispatching control of the comprehensive control module during grid connection, the photovoltaic power generation and the wind power generation are utilized to charge the energy storage battery as far as possible, the comprehensive utilization rate of energy is improved, and the energy storage module mainly plays a role of stable control of a direct current bus during off-grid.
The super capacitor plays a role in power supply guarantee meeting the traffic load of the impact road in a power supply system; the super capacitor has certain similarities with an energy storage battery in terms of external characteristics, energy flows in two directions, and the super capacitor can be charged and discharged. Unlike conventional power system loads, highway traffic loads exhibit many new characteristics, of which impact is one of the characteristics, mainly manifested as short-term high-power requirements, mainly based on super-high-power charging facilities and highway operation and maintenance equipment. The power requirement of the impact load can reach several times of that of normal operation sometimes, and if an energy storage battery system is used for meeting the short-time high-power requirement of the impact load, the instability of a direct current bus in a micro-grid system is easily caused, so that a super capacitor system is introduced, the charging and discharging time of the super capacitor system can be very short, the instantaneous power is high, and the optimal selection for meeting the impact load is realized. The short-time high-power requirement can cause sudden drop of the voltage of the direct current bus, and the voltage drop amplitude of the direct current bus is used as a condition for guaranteeing whether the super capacitor system is put into use for impact load power utilization.
The UPS provides uninterrupted power supply for important road traffic loads when the large power grid and the micro-grid system have faults; the most significant feature of the UPS is its stability, and in a conventional power system, the UPS is often used as an uninterruptible power supply for an important load. In the power supply system, the UPS is used as an important load power supply guarantee power supply when a large power grid and a micro-power grid simultaneously break down, and the important load can be ensured not to be powered off.
The diesel power generation system is used as an emergency guarantee power supply, and provides emergency power supply guarantee for road traffic loads when the power supplies are all in fault. The diesel power generation system is used as an emergency guarantee power supply in the power supply system and is the final emergency power supply guarantee when all the power supplies are in failure.
In terms of the design of the stable power supply method of the multi-energy storage power supply system, the bus voltage stabilization control and the source charge coordination control are considered respectively. The bus voltage stabilization control mainly refers to the voltage stabilization control of a high-voltage direct current bus and a high-voltage alternating current bus in a microgrid system. The high-voltage direct current bus and the high-voltage alternating current bus in the micro-grid system are controlled by a comprehensive control module in the micro-grid system and are specifically divided into two working conditions of grid connection and off-grid connection, and operation strategies under the two working conditions are explained below.
Under a first working condition, the power supply system operates in a grid-connected mode:
the control of a microgrid system in the prior art adopts a single module, namely an inverter module to stabilize a high-voltage direct-current bus, and in a grid-connected mode, photovoltaic power generation, wind power generation, an energy storage battery and a super capacitor all work in a current source mode. Therefore, the control in the above manner leads to poor power supply stability.
According to the invention, a mode that the high-voltage direct-current bus is jointly controlled by the energy storage battery conversion module, the super capacitor conversion module and the inversion module in a grid-connected mode is designed, so that the mutual redundancy effect among the modules can be realized, namely, the voltage of the direct-current bus in the micro-grid system can be still ensured to be stable after a single module breaks down. The direct current bus is controlled by the multiple modules together, so that an additional unstable factor, namely the coordination and coordination problem among the multiple modules, is introduced while the redundancy effect is achieved. Firstly, in addition to the above-mentioned dc bus stabilization control, the energy storage battery system still needs to perform operations such as conventional charging and discharging management on the energy storage battery, and the super capacitor also has similar problems, and in order to ensure that the super capacitor has the capability of stabilizing the dc bus, the super capacitor itself also needs conventional charging and discharging management and maintenance.
In order to solve the problems, the invention provides an improved control strategy for cooperatively controlling the voltage of the direct current bus by multiple modules, which is specifically described as ensuring that at least two modules work in a stable control mode of the voltage of the direct current bus at the same time, and selecting the most reasonable operation mode by the other module according to the current state of the other module. Under a microgrid system grid-connected operation mode, the inversion module is switched between a direct-current bus voltage-stabilizing control mode and an alternating-current bus droop control mode, and the energy storage battery conversion module and the super capacitor conversion module are respectively switched between the direct-current bus voltage-stabilizing control mode and the charge-discharge control mode.
Under the grid-connected mode, the control mode of the energy storage battery conversion module is determined as follows:
step 1: firstly, judging whether the energy storage battery needs to be subjected to charge and discharge management, if not, operating in a direct-current bus voltage stabilization control mode, and if so, continuing the judgment of the step 2;
step 2: synchronously judging whether the inversion module and the super capacitor conversion module operate in a direct current bus voltage stabilization control mode, if so, determining the energy storage battery conversion module as a charge and discharge control mode; and if only one of the inverter module and the super capacitor conversion module operates in the direct current bus voltage stabilization control mode, the energy storage battery conversion module is determined to be in the direct current bus voltage stabilization control mode.
Under the grid-connected mode, the control mode of the super capacitor conversion module is determined as follows:
and step 3: firstly, judging whether the amplitude of the voltage drop of the direct current bus exceeds a set seventh threshold, if so, operating in a direct current bus voltage stabilization control mode, and if not, continuing the judgment of the step 4;
and 4, step 4: judging whether the super capacitor needs to be subjected to charge and discharge management, if not, operating the super capacitor conversion module in a direct current bus voltage stabilization control mode, and if so, continuing the judgment of the step 5;
and 5: synchronously judging whether the inversion module and the energy storage battery conversion module operate in a direct current bus voltage stabilization control mode, if so, determining the super capacitor conversion module as a charge and discharge control mode; and if only one of the inverter module and the energy storage battery conversion module operates in the direct-current bus voltage stabilization control mode, the super capacitor conversion module is determined as the direct-current bus voltage stabilization control mode.
The above-mentioned amplitude of the dc bus voltage reduction refers to a difference between the dc bus voltage collected at the current time and the dc bus voltage collected at the previous time, and the seventh threshold in this embodiment is a dc bus voltage reduction rate, and the reduction rate is set to 15%.
Under the grid-connected mode, the control mode of the inverter module is determined as follows:
and 6: synchronously judging whether the super capacitor conversion module and the energy storage battery conversion module operate in a direct current bus voltage stabilization control mode, if so, continuing the judgment of the step 7, and if only one of the super capacitor conversion module and the energy storage battery conversion module operates in the direct current bus voltage stabilization control mode, determining the inversion module as the direct current bus voltage stabilization control mode;
and 7: judging whether the integrated control module reaches the control instruction of the droop mode of the alternating-current bus or not, if so, judging whether the integrated control module reaches the control instruction of the droop mode of the alternating-current bus or not
If the control mode is not the droop control mode, the inversion module determines the voltage stabilization control mode of the direct current bus.
When the micro-grid system operates in a grid-connected mode, in a source-load coordination control mode, a load bus special for road traffic is supplied with power by a large power grid and the micro-grid system.
And under the working condition II, the power supply system operates in an off-grid mode:
when the microgrid system operates in an off-grid mode, the inverter module works in an alternating current bus voltage stabilization control mode, the comprehensive control module determines a specific module operation mode according to the current SOC of the energy storage battery, the electric quantity of the super capacitor and the output state of photovoltaic power generation and wind power generation, after the comprehensive control module is determined, the specific operation mode is assigned to the photovoltaic power generation module, the wind power generation module, the energy storage battery module and the super capacitor module, and at least one of the energy storage battery conversion module and the super capacitor conversion module is ensured to operate in the direct current bus voltage stabilization control mode at the same moment.
During off-grid operation, the stable operation time of the power supply system and the operation mode of each module in the micro-grid system can be influenced by different actual traffic load and different matching conditions of new energy such as wind, light and the like, so that the reasonability of the source load coordination control in the off-grid mode is very important. In this embodiment, for the off-grid mode, the priority order of the power supply for the road traffic load is as follows: the switching and the exit of the different energy sources are respectively controlled according to the following modes:
firstly, an energy storage system (namely an energy storage battery and a super capacitor) is started to supply power to a load bus special for highway traffic, and the electric quantity change condition of the energy storage system is monitored in real time by a comprehensive control module. When the electric quantity of the energy storage system is reduced to a first threshold value (70% of the capacity of the energy storage system is set in the embodiment), the comprehensive control module starts the photovoltaic power generation assembly to charge the energy storage system. After the photovoltaic power generation assembly is started, the electric quantity change of the energy storage system is continuously detected, when the electric quantity of the energy storage system continuously drops to a second threshold value (40% of the capacity of the energy storage system is set in the embodiment), the comprehensive control module starts to start the wind power generation assembly to charge the energy storage system, and the quitting of the wind power generation assembly is when the electric quantity of the energy storage system is monitored to be higher than the second threshold value. In order to avoid frequent switching of the wind power generation assembly, 5% of hysteresis control quantity is respectively set for quitting or putting in the wind power generation assembly. Under the charging action of photovoltaic power generation, when the electric quantity of the energy storage battery rises to a fifth threshold (the embodiment is set to 95% of the capacity of the energy storage system), the photovoltaic power generation assembly exits the power generation mode. When the electric quantity of the energy storage system continuously drops to a third threshold value (10% of the capacity of the energy storage system is set in the embodiment), the UPS is started to supply power to the important load and simultaneously cut off the non-important load of road traffic, and the UPS supplies power to the important load alone. After the UPS is started, because the wind power generation and the photovoltaic power generation are continuously used for charging the energy storage system, when the electric quantity of the energy storage system rises to a sixth threshold value (which is set to be 50% of the capacity of the energy storage system in the embodiment), the UPS is stopped to supply power, the road traffic non-important load is closed again, and the micro-grid system power supply mode is switched back. When the electric quantity of the UPS continuously decreases to a fourth threshold value (10% of the capacity of the UPS is set in the embodiment), the diesel power generation system is started to supply power to the load bus special for the road traffic in an emergency mode, meanwhile, the electric quantity of the energy storage system is continuously detected, and when the electric quantity of the energy storage system rises to a sixth threshold value, the diesel power generation system stops supplying power and switches back to the microgrid system power supply mode.
Although embodiments of the present invention have been shown and described, it will be appreciated by 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, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. A stable power supply method of a multi-energy-source energy storage power supply system suitable for a traffic system is characterized by comprising the following steps:
constructing a multi-energy storage power supply system, wherein the multi-energy storage power supply system comprises a large power grid, a micro-grid system, a UPS (uninterrupted power supply), a diesel power generation system and an energy management system for controlling dispatching, wherein the large power grid, the micro-grid system, the UPS and the diesel power generation system can independently supply power to a load bus special for highway traffic; the micro-grid system comprises a photovoltaic power generation assembly, a wind power generation assembly and an energy storage system consisting of an energy storage battery and a super capacitor, wherein an alternating current bus and a direct current bus are arranged in the micro-grid system, the alternating current bus is respectively connected with a large power grid and a highway traffic special load bus, the direct current bus is respectively connected with a light energy conversion module, an energy storage battery conversion module, a super capacitor conversion module and a wind energy conversion module, an inversion module is connected between the direct current bus and the alternating current bus, and a comprehensive control module in the micro-grid system receives a scheduling instruction of an energy management system and controls the micro-grid system to operate;
the stable power supply method of the multi-energy storage power supply system comprises bus voltage stabilization control and source-charge coordination control;
when the micro-grid system operates in a grid-connected mode, in a source-load coordination control mode, a load bus special for road traffic is supplied with power by a large power grid and the micro-grid system; in a bus voltage stabilization control mode, under the scheduling of an integrated control module, at the same moment, at least two modules of an inverter module, an energy storage battery conversion module and a super capacitor conversion module operate in a direct current bus voltage stabilization control mode, wherein the inverter module is switched between the direct current bus voltage stabilization control mode and an alternating current bus droop control mode, and the energy storage battery conversion module and the super capacitor conversion module are respectively switched between the direct current bus voltage stabilization control mode and a charging and discharging control mode;
when little grid system operates in off-grid mode, the integrated control module is based on energy storage system's electric quantity and photovoltaic power generation and wind power generation's the condition of exerting oneself and is controlled, wherein, among the source load coordinated control mode, the priority order for highway traffic load power supply does in proper order: microgrid system, UPS, diesel generating system; in the bus voltage stabilization control mode, the inversion module works in an alternating current bus voltage stabilization control mode, and at least one of the energy storage battery conversion module and the super capacitor conversion module operates in a direct current bus voltage stabilization control mode at the same time.
2. The stable power supply method of the multi-energy-source energy storage power supply system suitable for the traffic system according to claim 1, wherein: in the off-grid mode, the source load coordination control method specifically comprises the following steps:
firstly, starting an energy storage system to supply power for a highway traffic dedicated load bus, monitoring the electric quantity of the energy storage system in real time by a comprehensive control module, starting a photovoltaic power generation assembly to charge the energy storage system by the comprehensive control module when the electric quantity of the energy storage system is reduced to a first threshold value, and stopping the photovoltaic power generation assembly from a power generation mode when the electric quantity of the energy storage system is increased to a fifth threshold value;
when the electric quantity of the energy storage system continuously drops to a second threshold value, the comprehensive control module starts the wind power generation assembly to charge the energy storage system, and when the electric quantity of the energy storage system is higher than the second threshold value, the wind power generation assembly exits from a power generation mode;
when the electric quantity of the energy storage system continuously drops to a third threshold value, the road traffic non-important load is cut off, the UPS is started to independently supply power to the important load, when the electric quantity of the energy storage system rises to a sixth threshold value, the UPS is stopped to supply power, the road traffic non-important load is closed again, and the micro-grid system supplies power again; when the electric quantity of the UPS is reduced to a fourth threshold value, the diesel power generation system is started to supply power to a load bus special for highway traffic, and when the electric quantity of the energy storage system is increased back to a sixth threshold value, the diesel power generation system is stopped to generate power and the micro-grid system supplies power again;
among the above threshold values, the following are sequentially from large to small: a fifth threshold, a first threshold, a sixth threshold, a second threshold, and a third threshold.
3. The stable power supply method of the multi-energy-source energy storage power supply system suitable for the traffic system according to claim 2, wherein: the first threshold is 70% of the capacity of the energy storage system, the second threshold is 40% of the capacity of the energy storage system, the third threshold is 10% of the capacity of the energy storage system, the fifth threshold is 95% of the capacity of the energy storage system, the sixth threshold is 50% of the capacity of the energy storage system, and the fourth threshold is 10% of the capacity of the UPS.
4. The stable power supply method of the multi-energy storage power supply system suitable for the transportation system according to claim 2 or 3, wherein: and 5% of hysteresis control quantity is set for the exit or the input of the wind power generation assembly respectively.
5. The stable power supply method of the multi-energy storage power supply system suitable for the transportation system as claimed in claim 1, wherein: in a grid-connected mode, the bus voltage stabilization control method specifically comprises the following steps:
the control mode of the energy storage battery conversion module is determined as follows:
step 1: firstly, judging whether the energy storage battery needs to be subjected to charge and discharge management, if not, operating in a direct-current bus voltage stabilization control mode, and if so, continuing the judgment of the step 2;
and 2, step: synchronously judging whether the inversion module and the super capacitor conversion module operate in a direct current bus voltage stabilization control mode, if so, determining the energy storage battery conversion module as a charge and discharge control mode; if only one of the inversion module and the super capacitor conversion module operates in the direct current bus voltage stabilization control mode, the energy storage battery conversion module is determined to be in the direct current bus voltage stabilization control mode;
the control mode of the super capacitor conversion module is determined as follows:
and 3, step 3: firstly, judging whether the amplitude of the voltage drop of the direct current bus exceeds a set seventh threshold, if so, operating in a direct current bus voltage stabilization control mode, and if not, continuing the judgment of the step 4;
and 4, step 4: judging whether the super capacitor needs to be subjected to charge and discharge management, if not, operating the super capacitor conversion module in a direct current bus voltage stabilization control mode, and if so, continuing the judgment of the step 5;
and 5: synchronously judging whether the inversion module and the energy storage battery conversion module operate in a direct current bus voltage stabilization control mode, if so, determining the super capacitor conversion module as a charge and discharge control mode; if only one of the inversion module and the energy storage battery conversion module operates in the direct-current bus voltage stabilization control mode, the super capacitor conversion module is determined to be in the direct-current bus voltage stabilization control mode;
the control mode of the inverter module is determined as follows:
step 6: synchronously judging whether the super capacitor conversion module and the energy storage battery conversion module operate in a direct current bus voltage stabilization control mode, if so, continuing the judgment of the step 7, and if only one of the super capacitor conversion module and the energy storage battery conversion module operates in the direct current bus voltage stabilization control mode, determining the inversion module as the direct current bus voltage stabilization control mode;
and 7: judging whether the integrated control module reaches the control instruction of the droop mode of the alternating-current bus or not, if so, judging whether the integrated control module reaches the control instruction of the droop mode of the alternating-current bus or not
If the control mode is not the droop control mode, the inversion module determines the voltage stabilization control mode of the direct current bus.
6. The stable power supply method of the multi-energy-source energy storage power supply system suitable for the traffic system according to claim 5, wherein: the amplitude of the drop of the dc bus voltage refers to a difference between the dc bus voltage collected at the current moment and the dc bus voltage collected at the previous moment, the seventh threshold is a dc bus voltage drop rate, and the drop rate is set to 15%.
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| CN117879117A (en) * | 2024-03-11 | 2024-04-12 | 南京欧陆电气股份有限公司 | Storage battery charging control system and control method thereof |
| CN117879117B (en) * | 2024-03-11 | 2024-05-24 | 南京欧陆电气股份有限公司 | Storage battery charging control system and control method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117879117A (en) * | 2024-03-11 | 2024-04-12 | 南京欧陆电气股份有限公司 | Storage battery charging control system and control method thereof |
| CN117879117B (en) * | 2024-03-11 | 2024-05-24 | 南京欧陆电气股份有限公司 | Storage battery charging control system and control method thereof |
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