Control Method of Highway Energy Guarantee System Based on DC Power Distribution

Abstract

The present invention provides a control method for a highway energy guarantee system based on DC power distribution, comprising the following steps: obtaining the q-axis current reference value and the d-axis current reference value at the input end of the AC / DC converter; performing current decoupling control according to the d-axis current, the d-axis current reference value, the q-axis current and the q-axis current reference value at the input end of the AC / DC converter to obtain the d-axis voltage compensation value and the q-axis voltage compensation value at the input end of the AC / DC converter; compensating the d-axis voltage through the d-axis voltage compensation value at the input end of the AC / DC converter, and compensating the q-axis voltage through the q-axis voltage compensation value at the input end of the AC / DC converter; transforming to obtain the three-phase voltage reference value at the input end of the AC / DC converter according to the compensated d-axis voltage and q-axis voltage at the input end of the AC / DC converter; generating a control signal for controlling the switching tubes in the AC / DC converter according to the three-phase voltage reference value at the input end of the AC / DC converter. The present invention can improve the power supply reliability of the intelligent transportation network.

Description

Technical Field

[0001] The present invention relates to the technical field of highway energy security, and particularly relates to a control method for a highway energy security system based on DC power distribution. Background Art

[0002] In recent years, in order to meet the development and service requirements of highway networks, the highway field has begun to promote the integration of energy, information, and transportation networks. A large number of facilities for sensing, collecting, communicating, analyzing, processing, and publishing the operating status of highway networks have been added along highways, further demanding high reliability and ultra-stability of the energy throughout the highway area, requiring stable energy supply throughout the area and 24 hours a day. Currently, the empowerment of highways is not designed and built according to scenarios and requirements, but is a simple superposition based on the original technical system. The original key technologies and physical conditions can no longer meet the needs of intelligence and wisdom, and even become a constraint on wisdom.

[0003] The areas along highway networks are long, narrow, and remote, mostly in urban-rural fringe areas or rural areas with low power supply reliability. At present, the method of taking power nearby is difficult to meet the requirements of the energy supply security and reliability for intelligent transportation information facilities on smart highways. Microgrid technology, characterized by the efficient local utilization of distributed renewable energy, is an effective solution for constructing highway energy networks. However, currently, the microgrids on highways do not have advanced and perfect key technologies, and have high input costs and poor economy, which become obstacles to the construction and development of green and low-carbon energy microgrids.

[0004] To meet the power consumption and communication requirements of intelligent transportation, autonomous driving, 5G communication, and other roadside intelligent devices, it is necessary to build a green transportation energy network to provide green energy security for smart highways. Carrying out distributed photovoltaic and energy storage construction and serving the intelligent devices of highway networks locally can reduce the long-distance transmission of electric energy, reduce power losses, and at the same time slow down the expansion of power distribution facilities and improve the power supply reliability of the intelligent transportation network.

[0005] In view of this, how to improve the power supply reliability of the intelligent transportation network, that is, how to provide good highway energy security has become an urgent problem to be solved. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a control method for a highway energy security system based on DC power distribution, which can reasonably control the highway energy security system, thereby improving the power supply reliability of the intelligent transportation network.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A control method for a highway energy guarantee system based on DC power distribution. The highway energy guarantee system includes a power supply station, an AC / DC converter, a DC / DC converter, and electrical equipment. The power supply station provides an AC power supply. The input end of the AC / DC converter is connected to the AC power supply, and the output end is connected to a DC bus. The input end of the DC / DC converter is connected to the DC bus, and the output end is connected to the electrical equipment. The control method includes the following steps: setting a reference voltage at the output end of the AC / DC converter and detecting the actual voltage at the output end of the AC / DC converter; obtaining a q-axis current reference value at the input end of the AC / DC converter, and obtaining a d-axis current reference value at the input end of the AC / DC converter according to the reference voltage and the actual voltage at the output end of the AC / DC converter; obtaining the actual current at the input end of the AC / DC converter and transforming it to obtain the d-axis current and q-axis current at the input end of the AC / DC converter; performing current decoupling control according to the d-axis current, d-axis current reference value, q-axis current, and q-axis current reference value at the input end of the AC / DC converter to obtain a d-axis voltage compensation value and a q-axis voltage compensation value at the input end of the AC / DC converter; obtaining the actual voltage at the input end of the AC / DC converter and transforming it to obtain the d-axis voltage and q-axis voltage at the input end of the AC / DC converter; compensating the d-axis voltage through the d-axis voltage compensation value at the input end of the AC / DC converter, and compensating the q-axis voltage through the q-axis voltage compensation value at the input end of the AC / DC converter; according to the compensated d-axis voltage and q-axis voltage at the input end of the AC / DC converter, transforming to obtain three-phase voltage reference values at the input end of the AC / DC converter; generating a control signal for controlling the switching tubes in the AC / DC converter according to the three-phase voltage reference values at the input end of the AC / DC converter.

[0009] The control method for the highway energy guarantee system based on DC power distribution further includes: setting a reference voltage at the output end of the DC / DC converter and detecting the actual voltage at the output end of the DC / DC converter; generating a control signal for controlling the switching tubes in the DC / DC converter according to the reference voltage and the actual voltage at the output end of the DC / DC converter.

[0010] Subtracting the reference voltage from the actual voltage at the output end of the AC / DC converter and inputting the result into a PI (Proportional Integral) controller, and obtaining the d-axis current reference value at the input end of the AC / DC converter through PI regulation.

[0011] Performing PWM (Pulse Width Modulation) modulation according to the three-phase voltage reference values at the input end of the AC / DC converter to generate a pulse signal for controlling the switching tubes in the AC / DC converter.

[0012] The reference voltage and the actual voltage at the output end of the DC / DC converter are subtracted and then input into a PI controller. After PI regulation and then phase-shift modulation, a pulse signal for controlling the switching tubes in the DC / DC converter is generated.

[0013] The highway energy guarantee system further includes a photovoltaic, energy storage or charging device connected to the DC bus.

[0014] The electrical equipment includes signal base stations, and one signal base station is set at every preset distance.

[0015] The power supply station is a service area, a toll station or a roadside device with an AC power supply.

[0016] Advantages of the present invention:

[0017] The control method of the highway energy guarantee system for DC power distribution of the present invention. The design of the highway energy guarantee system can reduce the long-distance transmission of electric energy, reduce power loss, and provide guarantee for the power consumption of highways. Moreover, by controlling the switching tubes in the converter according to the output parameters of the converter ports, the highway energy guarantee system can be reasonably controlled, thereby improving the power supply reliability of the intelligent transportation network. Description of the drawings

[0018] Figure 1 It is a block diagram of the highway energy guarantee system according to an embodiment of the present invention;

[0019] Figure 2 It is a structural diagram of the highway energy guarantee system according to a specific embodiment of the present invention;

[0020] Figure 3 It is a flowchart of the control method of the highway energy guarantee system for DC power distribution according to an embodiment of the present invention;

[0021] Figure 4 It is a control block diagram corresponding to the control method of the highway energy guarantee system for DC power distribution according to an embodiment of the present invention;

[0022] Figure 5 It is a flowchart of the control method of the highway energy guarantee system for DC power distribution according to a further embodiment of the present invention;

[0023] Figure 6 It is a control block diagram corresponding to the control method of the highway energy guarantee system for DC power distribution according to a further embodiment of the present invention. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] As Figure 1 shown, the highway energy guarantee system in the embodiment of the present invention includes a power supply station, an AC / DC converter, a DC / DC converter, and an electrical device. The power supply station provides an AC power supply. The input end of the AC / DC converter is connected to the AC power supply, and the output end is connected to the DC bus. The input end of the DC / DC converter is connected to the DC bus, and the output end is connected to the electrical device.

[0026] In an embodiment of the present invention, as Figure 2 shown, the electrical device can be a signal base station, and a signal base station can be set at every preset distance, for example, at every interval of 5 to 10 km.

[0027] In an embodiment of the present invention, the highway energy guarantee system may further include a photovoltaic, energy storage, or charging device connected to the DC bus. The photovoltaic device includes a photovoltaic panel and a corresponding DC / DC converter. The grid connection of photovoltaic power generation can be realized by connecting the DC / DC converter to the DC bus. The energy storage device includes an energy storage battery and a corresponding DC / DC converter. The peak shaving and valley filling and the improvement of power quality can be realized by connecting the DC / DC converter to the DC bus. The charging device can be an electric vehicle charging pile, which can realize the charging of electric vehicles and provide guarantee for the popularization of electric vehicles and the convenience of using them on highways.

[0028] As Figure 2 shown, at least one of the photovoltaic, energy storage, and charging devices can be set together with a corresponding signal base station to form an energy sub-station. Through the setting of the energy sub-station, the centralized management of the signal base station and the DC devices such as the photovoltaic, energy storage, and charging devices can be realized.

[0029] In an embodiment of the present invention, the power supply station can be a service area, a toll station, or a roadside device with an AC power supply. Through a 10 kV or 35 kV AC line drawn from a power source point such as a service area, a toll station, or other adjacent roadside devices, an energy sub-station is set according to the load situation, and a step-down transformer is used to convert 35 kV or 10 kV AC into 380 V AC, and then it is converted into 800 V DC through an AC / DC converter and supplied to the signal base station and the photovoltaic, energy storage, and charging devices through the DC bus, providing energy guarantee for these devices on the highway.

[0030] To improve the reliability of energy security, the present invention proposes a control method for a highway energy security system based on DC power distribution.

[0031] As Figure 3 shown, the control method for the highway energy security system based on DC power distribution according to the embodiments of the present invention includes the following steps:

[0032] S1. Set the reference voltage at the output end of the AC / DC converter and detect the actual voltage at the output end of the AC / DC converter.

[0033] S2. Obtain the q-axis current reference value at the input end of the AC / DC converter, and obtain the d-axis current reference value at the input end of the AC / DC converter according to the reference voltage and the actual voltage at the output end of the AC / DC converter.

[0034] S3. Obtain the actual current at the input end of the AC / DC converter, and transform it to obtain the d-axis current and the q-axis current at the input end of the AC / DC converter.

[0035] S4. Perform current decoupling control according to the d-axis current, the d-axis current reference value, the q-axis current, and the q-axis current reference value at the input end of the AC / DC converter to obtain the d-axis voltage compensation value and the q-axis voltage compensation value at the input end of the AC / DC converter.

[0036] S5. Obtain the actual voltage at the input end of the AC / DC converter, and transform it to obtain the d-axis voltage and the q-axis voltage at the input end of the AC / DC converter.

[0037] S6. Compensate the d-axis voltage through the d-axis voltage compensation value at the input end of the AC / DC converter, and compensate the q-axis voltage through the q-axis voltage compensation value at the input end of the AC / DC converter.

[0038] S7. According to the compensated d-axis voltage and q-axis voltage at the input end of the AC / DC converter, transform to obtain the three-phase voltage reference value at the input end of the AC / DC converter.

[0039] S8. Generate a control signal for controlling the switching tubes in the AC / DC converter according to the three-phase voltage reference value at the input end of the AC / DC converter.

[0040] The control block diagrams corresponding to the above steps S1 to S8 are shown in Figure 4 , and overall, it realizes a double closed-loop control of the current inner loop and the voltage outer loop for the AC / DC converter.

[0041] As Figure 4 shown, first set the reference voltage V ref at the output end of the AC / DC converter, and detect the actual voltage U dc1, and then the reference voltage V at the output end of the AC / DC converter ref is subtracted from the actual voltage U dc1 and the result is input into a PI controller. After PI regulation, the d-axis current reference value i d * at the input end of the AC / DC converter is obtained.

[0042] Meanwhile, the q-axis current reference value i q * at the input end of the AC / DC converter is obtained. In an embodiment of the present invention, the reference active power and reference reactive power at the input end of the AC / DC converter can be set, and the q-axis current reference value i q * at the input end of the AC / DC converter is calculated according to the definition of instantaneous complex power.

[0043] The definition of instantaneous complex power is:

[0044]

[0045]

[0046] According to the definition of instantaneous complex power, the calculation formula for the q-axis current reference value can be obtained:

[0047]

[0048] Wherein, in the definition of instantaneous complex power, the voltage and current are represented by V and I respectively, and in the calculation formula for the q-axis current reference value, the voltage and current are represented by e and i respectively. i q * represents the q-axis current reference value, e d and e q respectively represent the d-axis voltage and q-axis voltage at the input end of the AC / DC converter, and e d and e q can be obtained through detection and transformation.

[0049] Then, the actual current at the input end of the AC / DC converter, i.e., the three-phase current i A,B,C , can be detected and transformed from the abc coordinate system to the dq coordinate system, and the d-axis current i d and q-axis current i q at the input end of the AC / DC converter can be obtained.

[0050] After obtaining the d-axis current i d , d-axis current reference value i d *, q-axis current i q and q-axis current reference value i q * at the input end of the AC / DC converter, current decoupling control can be performed according to these four parameters to obtain the d-axis voltage compensation value and q-axis voltage compensation value at the input end of the AC / DC converter.

[0051] Meanwhile, the actual voltage at the input of the AC / DC converter can be detected, i.e., the three-phase voltage e A,B,C , which is transformed from the abc coordinate system to the dq coordinate system, and then the d-axis voltage e d and the q-axis voltage e q at the input of the AC / DC converter can be obtained.

[0052] Then, the compensation value of the d-axis voltage at the input of the AC / DC converter is added to the d-axis voltage e d through an adder, and the compensation value of the q-axis voltage at the input of the AC / DC converter is added to the q-axis voltage e q through an adder. After that, through the transformation from the dq coordinate system to the abc coordinate system, the three-phase voltage reference values u a *, u b *, and u c * at the input of the AC / DC converter are obtained.

[0053] Finally, based on the three-phase voltage reference values u a *, u b *, and u c * at the input of the AC / DC converter, PWM modulation is performed to generate the pulse signal 1 for controlling the switching tubes in the AC / DC converter.

[0054] The above steps S1 to S8 are the control process for the AC / DC converter.

[0055] In an embodiment of the present invention, the control method of the highway energy guarantee system based on DC distribution further includes the control process for the DC / DC converter.

[0056] As Figure 5 shown, the control method of the highway energy guarantee system based on DC distribution in the embodiment of the present invention further includes:

[0057] S9, setting the reference voltage at the output of the DC / DC converter and detecting the actual voltage at the output of the DC / DC converter.

[0058] S10, generating a control signal for controlling the switching tubes in the DC / DC converter according to the reference voltage and the actual voltage at the output of the DC / DC converter.

[0059] The control block diagram corresponding to the above steps S9 to S10 is shown in Figure 6 , and overall, it realizes a voltage stabilization control for the DC / DC converter.

[0060] As Figure 6 shown, first, the reference voltage U dc ref at the output of the DC / DC converter is set, and the actual voltage Udc2 , and then the reference voltage U at the output end of the DC / DC converter dc ref and the actual voltage U dc2 are subtracted and then input into a PI controller. After PI regulation and then phase-shift modulation, a pulse signal 2 for controlling the switching tubes in the DC / DC converter is generated.

[0061] Steps S9 to S10 can be implemented in the same highway energy guarantee system as steps S1 to S8 to achieve an optimal power distribution control effect.

[0062] According to the control method of the highway energy guarantee system for DC power distribution according to the embodiments of the present invention, the design of the highway energy guarantee system can reduce the long-distance transmission of electric energy, reduce power loss, and provide guarantee for highway power consumption. Moreover, by controlling the switching tubes in the converter according to the output parameters of the converter ports, the highway energy guarantee system can be reasonably controlled, thereby improving the power supply reliability of the intelligent transportation network.

[0063] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is two or more unless otherwise specifically defined.

[0064] In the present invention, unless otherwise clearly defined and limited, the terms such as "installation", "connection", "connection", "fixation" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the connection inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0065] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0066] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0067] Any process or method description represented in a flowchart or otherwise described herein can be understood to represent a module, segment, or portion of code including one or more executable instructions for implementing a specific logical function or process, and the scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a manner that is not shown or discussed, including in a substantially simultaneous manner according to the functions involved or in a reverse order, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0068] The logic and / or steps represented in a flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing a logical function, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in connection with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion having one or more wirings (electronic device), a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0069] It should be understood that various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one of the following techniques known in the art or a combination thereof can be used: discrete logic circuits having logic gate circuits for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0070] Those of ordinary skill in the art can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0071] In addition, each functional unit in various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically alone, or two or more units can be integrated into one module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0072] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A control method for a highway energy guarantee system based on DC power distribution, characterized in that The highway energy guarantee system includes a power supply station, an AC / DC converter, a DC / DC converter, and electrical equipment. The power supply station provides an AC power supply. The input end of the AC / DC converter is connected to the AC power supply, and the output end is connected to the DC bus. The input end of the DC / DC converter is connected to the DC bus, and the output end is connected to the electrical equipment. The control method includes the following steps: Set the reference voltage at the output end of the AC / DC converter and detect the actual voltage at the output end of the AC / DC converter; Obtain the q-axis current reference value at the input end of the AC / DC converter, and obtain the d-axis current reference value at the input end of the AC / DC converter according to the reference voltage and the actual voltage at the output end of the AC / DC converter; Obtain the actual current at the input end of the AC / DC converter, and transform it to obtain the d-axis current and the q-axis current at the input end of the AC / DC converter; Perform current decoupling control according to the d-axis current, d-axis current reference value, q-axis current, and q-axis current reference value at the input end of the AC / DC converter to obtain the d-axis voltage compensation value and the q-axis voltage compensation value at the input end of the AC / DC converter; Obtain the actual voltage at the input end of the AC / DC converter, and transform it to obtain the d-axis voltage and the q-axis voltage at the input end of the AC / DC converter; Compensate the d-axis voltage through the d-axis voltage compensation value at the input end of the AC / DC converter, and compensate the q-axis voltage through the q-axis voltage compensation value at the input end of the AC / DC converter; According to the compensated d-axis voltage and q-axis voltage at the input end of the AC / DC converter, transform to obtain the three-phase voltage reference value at the input end of the AC / DC converter; Generate a control signal for controlling the switching tubes in the AC / DC converter according to the three-phase voltage reference value at the input end of the AC / DC converter.

2. The control method of the highway energy guarantee system based on DC power distribution according to claim 1, wherein, It further includes: Set the reference voltage at the output end of the DC / DC converter and detect the actual voltage at the output end of the DC / DC converter; Generate a control signal for controlling the switching tubes in the DC / DC converter according to the reference voltage and the actual voltage at the output end of the DC / DC converter.

3. The control method of the highway energy guarantee system based on DC power distribution according to claim 2, wherein, Subtract the reference voltage from the actual voltage at the output end of the AC / DC converter and input it into a PI controller. After PI regulation, obtain the d-axis current reference value at the input end of the AC / DC converter.

4. The control method of the highway energy guarantee system based on DC power distribution according to claim 3, wherein, Perform PWM modulation according to the three-phase voltage reference value at the input end of the AC / DC converter to generate a pulse signal for controlling the switching tubes in the AC / DC converter.

5. The control method of the highway energy guarantee system based on DC power distribution according to claim 4, characterized in that, Subtract the reference voltage from the actual voltage at the output end of the DC / DC converter and input it into a PI controller. After PI regulation and then phase-shift modulation, generate a pulse signal for controlling the switching tubes in the DC / DC converter.

6. The control method of the highway energy guarantee system based on DC power distribution according to claim 5, characterized in that, The highway energy guarantee system further includes a photovoltaic, energy storage, or charging device connected to the DC bus.

7. The control method of the highway energy guarantee system based on DC power distribution according to claim 6, characterized in that, The electrical equipment includes signal base stations, and one signal base station is set at a preset interval.

8. The control method of the highway energy guarantee system based on DC power distribution according to claim 7, characterized in that, The power supply station is a service area, a toll station, or a roadside device with an AC power supply.

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