Through the same-phase traction power supply substation-level control system

Abstract

The present application discloses a through-phase traction power supply converter station-level control system, comprising: a data acquisition and processing module that processes the converter's electrical data to obtain the converter's electrical quantities; a mode discrimination module that determines the converter's target control mode for the traction grid side based on system-level control instructions and electrical quantities; a public grid side control module that controls the converter's public grid side based on the electrical quantities and outputs a first modulation wave for the converter's public grid side; a traction grid side control module that controls the converter's traction grid side to enter the target control mode and then controls the converter's traction grid side based on the electrical quantities and outputs a second modulation wave for the converter's traction grid side; a sequence control module that discriminates the converter station's operating status and controls the converter station's operation according to the converter station's start-stop process; and a modulation module that generates a trigger pulse based on two modulation waves, thereby generating a valve base control signal. Thus, through-phase traction power supply converter station-level control is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of power supply system control, and in particular to a through-phase traction power supply converter station-level control system. Background Art

[0002] Railway (railway transit) traction power supply systems are the energy source for electrified railways and urban rail transit systems, and are crucial to their safe, stable, and economical operation. The traction power supply systems for my country's high-speed, heavy-haul, and intercity rapid rail transit all utilize a "single-phase 50Hz AC + unilateral power supply" system. Power-splitting zones ("phase separation") are required every 10-30km. This current phase separation system consistently hinders the safe, reliable, efficient, and high-quality operation of my country's electrified railways. The key to addressing this issue is co-phase traction power supply technology.

[0003] In-phase traction power supply technology can be divided into three categories: quasi-in-phase traction power supply technology, virtual in-phase traction power supply technology, and through-phase traction power supply technology. Through-phase traction power supply technology is a bilateral traction power supply system that mainly relies on the AC-AC conversion of static power converters (SPCs) to achieve power conversion between the three-phase external power grid and the single-phase traction grid. Its basic characteristics are:

[0004] 1) Completely eliminate electrical phase separation and achieve true same-phase power supply. The locomotive does not need excessive phase separation during the entire process of catenary operation, which is safe, reliable and has no speed loss.

[0005] 2) Ensure the three-phase system balance of the external power system, no need for dynamic reactive power compensation, and harmonic compliance;

[0006] 3) The three-phase power grid and traction system are completely decoupled, with almost no mutual influence and strong power grid fault ride-through capability;

[0007] 4) High utilization rate of traction transformer capacity, reducing fixed capacity and operating costs of traction stations;

[0008] 5) The external power supply has low short-circuit capacity requirements, reduces the cost of switchgear, and has strong grid adaptability;

[0009] 6) Realize bilateral power supply, strong power supply capacity, which is conducive to increasing the distance between traction stations, stabilizing the contact network voltage, and effectively improving power supply reliability;

[0010] 7) Traction system fault current limitation: when the contact network is short-circuited, the current is quickly limited to within the rated value, reducing the cost of grounding and connection mechanisms;

[0011] 8) The braking energy can be controlled to reduce the amount of feedback to the three-phase system, making full use of the braking energy and saving 10% to 20% of the traction energy;

[0012] The Beijing Metro New Airport Line is building a single-phase, 50Hz, 25kV AC electrified railway fully-through co-phase traction power supply system, which will fully decouple the external power system from the traction grid power supply arm through a static power converter.

[0013] The technical solutions of related technologies are mainly aimed at the specific control methods of SPC devices. There are only the architecture and control methods of the through-phase traction power supply system, or the specific control methods of the public grid side and traction grid side of the converter. There is a lack of technical solutions for the through-phase traction power supply substation-level control system, which needs to be solved urgently. Summary of the Invention

[0014] The present application provides a through-phase traction power supply converter station-level control system to achieve through-phase traction power supply converter station-level control.

[0015] In a first aspect, an embodiment of the present application provides a through-phase traction power supply converter station-level control system, comprising: a data acquisition and processing module for real-time acquisition of electrical data of the converter, and processing the electrical data to obtain the electrical quantity of the converter; a mode discrimination module for determining a target control mode of the traction network side of the converter according to a system-level control instruction and the electrical quantity; a public grid side control module for controlling the public grid side of the converter according to the electrical quantity and outputting a first modulation wave of the public grid side of the converter; a traction grid side control module for controlling the traction grid side of the converter to enter the target control mode, and then controlling the traction grid side of the converter according to the electrical quantity and outputting a second modulation wave of the traction grid side of the converter; a sequence control module for discriminating the operating status of the converter station and starting or stopping the operation of the converter station according to the start-stop process of the converter station; a modulation module for modulating the first modulation wave of the public grid side of the converter and the second modulation wave of the traction grid side of the converter to generate a trigger pulse, and generating a valve base control signal from the trigger pulse.

[0016] Optionally, in one embodiment of the present application, the traction network side control module includes: an AC voltage and frequency control unit, which is used to control the AC voltage set by the traction network side output of the converter to achieve flexible current sharing of multiple converters in the station; an AC current and frequency control unit, which is used to control the AC current set by the traction network side output of the converter; an active / reactive power control unit, which is used to control the active and reactive power set by the traction network side output of the converter; and an output unit, which is used to select one of the AC voltage and frequency control unit, the AC current and frequency control unit and the active / reactive power control unit according to the target control mode determined by the mode discrimination module, to control the traction network side of the converter to output the second modulation wave of the traction network side of the converter.

[0017] Optionally, in one embodiment of the present application, the traction network side control module further includes: an active filtering functional unit for suppressing locomotive characteristic subharmonics; and an active damping functional unit for preventing contact network system oscillation.

[0018] Optionally, in one embodiment of the present application, the mode discrimination module is further used to determine that the target control mode on the traction network side of the converter is an AC current and frequency control mode when it is judged that a contact network short circuit fault has occurred in the system based on the electrical quantity; and when it is judged that the contact network short circuit fault has not occurred in the system, determine that the target control mode on the traction network side of the converter is the control mode in the system-level control instruction.

[0019] Optionally, in one embodiment of the present application, the mode discrimination module is further used to determine that a contact network short-circuit fault has occurred in the system when the output side current of the converter is greater than a threshold current and the duration of being greater than the threshold current is greater than a first preset duration; and to determine that the contact network short-circuit fault in the system has been eliminated when the output side current of the converter is greater than a threshold voltage and the duration of being greater than the threshold voltage is greater than a second preset duration.

[0020] Optionally, in one embodiment of the present application, the mode identification module is further used to determine that the target control mode on the traction network side of the converter is the active / reactive power control mode when the power of the converter station reaches the total tolerance of the equipment in the station under the AC voltage and frequency control mode, and after receiving the recovery instruction issued by the system-level control, determine that the target control mode on the traction network side of the converter returns to the AC voltage and frequency control mode.

[0021] Optionally, in one embodiment of the present application, the public network side control module includes:

[0022] A DC voltage control unit, used to control the converter valve group to maintain a set DC voltage;

[0023] The reactive power control unit is used to control the reactive power set by the public grid side input of the converter.

[0024] Optionally, in one embodiment of the present application, the sequential control module is further used to determine the operating status of the converter station, including normal operation of the entire station, exit of some converters, and exit of the entire station; control the start and stop process of the converter station according to the system-level control sequence instructions and the electrical quantity, generate the action signal of the circuit breaker in the converter station, and the unlocking signal of the power devices on the public grid side and the traction grid side of the converter.

[0025] The second embodiment of the present application provides a through-phase traction power supply converter station-level control method, using the above-mentioned through-phase traction power supply converter station-level control system, the method includes the following steps: collecting the electrical data of the converter, and processing the electrical data to obtain the electrical quantity of the converter; determining the target control mode of the traction network side of the converter according to the system-level control instructions and the electrical quantity; controlling the start and stop process of the converter according to the system-level control sequence instructions and the electrical quantity, generating an action signal of the circuit breaker in the converter, and the converter The unlocking signal of the power devices on the public grid side of the converter and the traction grid side of the converter; controlling the public grid side of the converter according to the electrical quantity, and outputting the first modulation wave of the public grid side of the converter; after controlling the traction grid side of the converter to enter the target control mode, controlling the traction grid side of the converter according to the electrical quantity, and outputting the second modulation wave of the traction grid side of the converter; modulating the first modulation wave on the public grid side of the converter and the second modulation wave on the traction grid side of the converter to generate a trigger pulse, and generating a valve base control signal from the trigger pulse.

[0026] Optionally, in one embodiment of the present application, determining the target control mode of the traction network side of the converter based on the system-level control instruction and the electrical quantity includes: when judging that a contact network short-circuit fault has occurred in the system based on the electrical quantity, determining that the target control mode of the traction network side of the converter is an AC current and frequency control mode; when judging that the contact network short-circuit fault has not occurred in the system, determining that the target control mode of the traction network side of the converter is the control mode in the system-level control instruction.

[0027] The embodiments of the present application acquire the electrical data of the converter in real time and process the electrical data to obtain the electrical quantities of the converter. The target control mode of the converter's traction grid side is determined based on the system-level control instructions and the electrical quantities. The public grid side of the converter is controlled based on the electrical quantities, and a first modulation wave of the public grid side of the converter is output. After the traction grid side of the converter enters the target control mode, the traction grid side of the converter is controlled based on the electrical quantities, and a second modulation wave of the traction grid side of the converter is output. The first modulation wave of the public grid side of the converter and the second modulation wave of the traction grid side of the converter are modulated to generate a trigger pulse, which is then used to generate a valve base control signal. This achieves through-phase traction power supply converter station-level control.

[0028] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0030] Figure 1 This is a structural diagram of the through-phase traction power supply converter station;

[0031] Figure 2 This is a schematic diagram of the structure of a through-phase traction power supply converter station-level control system provided according to an embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of a framework of a through-phase traction power supply converter station-level control system provided according to an embodiment of the present application;

[0033] Figure 4 Schematic diagram of traction grid-side control modes and switching conditions of a through-phase traction power supply converter station-level control system provided according to an embodiment of the present application;

[0034] Figure 5 This is a control block diagram of the public grid side of the converter provided according to an embodiment of the present application;

[0035] Figure 6 This is a block diagram of AC voltage and frequency control on the traction grid side of a converter provided according to an embodiment of the present application;

[0036] Figure 7 This is a block diagram of AC current and frequency control on the traction grid side of a converter provided according to an embodiment of the present application;

[0037] Figure 8 This is a block diagram of active / reactive power control on the traction grid side of a converter provided according to an embodiment of the present application;

[0038] Figure 9 A start-stop flow chart of a through-phase traction power supply converter station provided according to an embodiment of the present application;

[0039] Figure 10 This is a flow chart of a through-phase traction power supply converter station-level control method provided according to an embodiment of the present application.

[0040] Figure numerals: data acquisition and processing module-100, mode discrimination module-200, public grid side control module-300, traction grid side control module-400, AC voltage and frequency control unit-401, AC current and frequency control unit-402, active / reactive power control unit-403, output unit-404, sequence control module-500, modulation module-600. DETAILED DESCRIPTION

[0041] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0042] In the related art, there are only the architecture and control method of the through-phase traction power supply system, or the specific control method of the converter public grid side and the traction grid side, but there is a lack of technical solutions for the through-phase traction power supply converter station-level control system. The technical solution of this application is for the through-phase traction power supply converter station-level control system, such as Figure 1 As shown in the figure, a through-phase traction power supply converter station structure is demonstrated. Figure 1 The common-phase traction power supply converter station consists of a three-phase conventionally connected first traction transformer T1, a three-phase conventionally connected second traction transformer T2, one or more parallel converters, and several switches. The phase sequence of the three phases of the public AC grid is represented by A, B, and C, with phase A leading phase B by 120° and phase A lagging phase C by 120°. The connection relationship of each component in the through-phase traction power supply substation is as follows: the primary ports of traction transformers T1 and T2 are connected to the synchronous public AC grid phases A, B, and C respectively through three-phase circuit breakers 106 and 107, and the secondary ports are connected to the station AC busbars Ac, Bc, and Cc respectively through three-phase circuit breakers 60GT and 70GT; the input ports of each converter are connected to Ac, Bc, and Cc respectively, one output port is connected to the traction busbar T-bus, and the other output port is connected to the centralized grounding terminal in the traction station; the traction busbar T-bus is connected to the overhead line T through the single-phase circuit breaker 60G, the rails are connected to the centralized grounding terminal through the return line, and the centralized grounding terminal is connected to the earth grid.

[0043] The following describes a through-cophase traction power supply converter station-level control system according to an embodiment of the present invention based on the through-cophase traction power supply converter station structure.

[0044] Specifically, Figure 2 This is a schematic diagram of the structure of a through-phase traction power supply converter station-level control system provided according to an embodiment of the present application. Figure 3 This is a schematic diagram of the framework of a through-phase traction power supply substation-level control system provided according to an embodiment of the present application.

[0045] like Figure 2 and Figure 3 As shown, the through-phase traction power supply converter station-level control system includes: a data acquisition and processing module 100, a mode determination module 200, a public grid side control module 300, a traction grid side control module 400, a sequence control module 500 and a modulation module 600.

[0046] Optionally, the station-level converter control is located between the system-level control and the valve-based control, and exchanges data with them.

[0047] Optionally, in an embodiment of the present application, the data acquisition and processing module 100 is used to acquire electrical data of the converter in real time, and process the electrical data to obtain electrical quantities of the converter.

[0048] Specifically, the electrical quantities collected by the data collection and processing module 100 include the converter input voltage u G1 , output voltage u G3 , output variable secondary current i HE1 , filter current i HE2 , valve group DC voltage u D The above data are processed, including phase locking of single-phase voltage on the input and output sides, calculation of instantaneous power on the output side and calculation of average value of valve group voltage, to obtain the input voltage phase ωt rec , output voltage phase ωt inv , output current i T , output active power P inv , output reactive power Q inv , average value of valve group voltage u Davr , where P inv , Q inv 、i T Upload to system level control.

[0049] Optionally, in an embodiment of the present application, the mode determination module 200 is configured to determine a target control mode of the traction network side of the converter according to system-level control instructions and electrical quantities.

[0050] Specifically, the mode discrimination module 200 is connected to the data acquisition and processing module 100, and can determine which control mode is adopted for the traction network side control. The optional control modes include AC voltage and frequency control mode (VF mode), AC current and frequency control mode (FCL mode) and active / reactive power control mode (PQ mode). Figure 4 Schematic diagram of the traction grid-side control mode and switching conditions of the through-phase traction power supply converter station-level control system provided according to an embodiment of the present application.

[0051] Optionally, in an embodiment of the present application, the mode discrimination module 200 is further used to determine that the target control mode of the traction network side of the converter is the AC current and frequency control mode when it is judged based on electrical quantities that a contact network short circuit fault has occurred in the system; and when it is judged that no contact network short circuit fault has occurred in the system, determine that the target control mode of the traction network side of the converter is the control mode in the system-level control instruction.

[0052] As a possible implementation method, in an embodiment of the present application, when the output side current of the converter is greater than the threshold current and the duration of being greater than the threshold current is greater than a first preset time length, it is determined that a contact network short circuit fault has occurred in the system; when the output voltage of the converter is greater than the threshold voltage and the duration of being greater than the threshold voltage is greater than a second preset time length, it is determined that the contact network short circuit fault of the system has been eliminated.

[0053] Specifically, the mode discrimination module 200 receives a mode instruction from the system level control and determines the mode according to the output side current i G9 , output voltage u G3 Determine whether the system has a contact network short circuit fault; if i G9 Greater than the threshold current I set , lasting longer than T set1 , it is determined that the system has a contact network short circuit fault. If u G3 Greater than the threshold voltage U set , lasting longer than T set2 , it is determined that the contact network short-circuit fault has been removed; during the system contact network short-circuit fault, the traction network side control mode is fixed to FCL control, otherwise it is the same as the mode instruction issued by the system-level control.

[0054] Optionally, in an embodiment of the present application, the mode discrimination module 200 is further used to determine that the target control mode of the traction network side of the converter is the active / reactive power control mode when the power of the converter station reaches the total tolerance of the equipment in the station under the AC voltage and frequency control mode, and after receiving the recovery instruction issued by the system-level control, determine that the target control mode of the traction network side of the converter returns to the AC voltage and frequency control mode.

[0055] Optionally, in an embodiment of the present application, the public grid side control module 300 is configured to control the public grid side of the converter according to the electrical quantity, and output a first modulation wave of the public grid side of the converter.

[0056] Specifically, the public grid side control module 300 is connected to the data acquisition and processing module 100, which can realize the constant DC voltage / reactive power control (UdcQ control) on the public grid side of the converter. The reactive power control can also be replaced by power factor correction, AC voltage control and other functions.

[0057] Optionally, in an embodiment of the present application, the public network side control module 300 includes:

[0058] The DC voltage control unit 301 is used to control the converter valve group to maintain the set DC voltage; the reactive power control unit 302 is used to control the reactive power input set by the converter public grid side. The input quantity of the public grid side control module includes the input voltage u G1 , input voltage phase ωt rec , output active power Pinv , valve group current i HE , valve group DC voltage u D , and the valve group DC voltage reference value U issued by the system level control and protection D * and reactive current reference value I qrec *, the output is the modulation wave u on the public network side of the valve group rec *.

[0059] In the embodiment of the present application, the public grid side control adopts a double closed-loop control structure, the outer loop is the DC voltage and reactive power control, and the inner loop is the valve group current control in the stationary coordinate system. The control structure is as follows Figure 5 As shown. In terms of outer loop DC voltage control, the valve group DC voltage reference value U D * Subtract the valve group DC voltage u Dx The sliding average value is used as the input of the PI controller, and the output is limited and combined with the feedforward current I p_fd Add and limit the active current reference value I prec *; Active current reference value I prec * and reactive current reference value I qrec *Respectively with input voltage u G1 The sine value of sinωt rec , cosine value cosωt rec Multiply, add and subtract valve group current i HE x, get the input of the inner loop PR controller; active current reference value I prec * and reactive current reference value I qrec *Respectively with input voltage u G1 The cosine value of cosωt rec , sine value sinωt rec Multiply by the public network side impedance ωL rec , the compensation voltage u on the reactance is obtained by subtracting the latter from the former L ;Valve group public network side voltage u Rec2 Subtract u L and the output of the PR controller, divided by the valve group DC voltage u Dx After limiting, the modulation wave u on the public network side of valve group x is obtained recx When the locking signal BlkRec is 0, the grid is locked, and the integral and PR components are reset to zero. The inner-loop PR controller includes a fundamental frequency component to eliminate steady-state errors in current control. Other resonant components can also be added to reduce harmonics in the valve group current.

[0060] Feedforward current I p_fd The calculation formula is shown in (1), where U 2N_rec It is the rated voltage of the public network side of the valve group.

[0061]

[0062] During the actual implementation process, the public grid side control module 300 of the embodiment of the present application may also add other control functions, such as active filtering function, which is used to suppress public grid side harmonics; active damping function, which is used to prevent public grid system oscillation and improve system stability; low voltage ride-through function, which is used to maintain converter operation when the voltage drops due to a public grid side fault, etc.

[0063] Optionally, in an embodiment of the present application, the traction network side control module 400 is used to control the traction network side of the converter to enter a target control mode, control the traction network side of the converter according to electrical quantities, and output a second modulation wave of the traction network side of the converter.

[0064] Specifically, the traction network side control module 400 is connected to the data acquisition and processing module 100 and the mode discrimination module 200, and can generate a modulated wave on the traction network side.

[0065] Optionally, in an embodiment of the present application, the traction network side control module includes:

[0066] The AC voltage and frequency control unit 401 is used to control the set AC voltage output on the traction network side of the converter and achieve flexible current sharing among multiple converters within the station. The AC current and frequency control unit 402 is used to control the set AC current output on the traction network side of the converter. The active / reactive power control unit 403 is used to control the set active and reactive power output on the traction network side of the converter. The output unit 404 is used to select one of the AC voltage and frequency control unit, AC current and frequency control unit, and active / reactive power control unit based on the target control mode determined by the mode discrimination module 200 to control the traction network side of the converter and output a second modulation wave on the traction network side of the converter.

[0067] Specifically, the traction grid side control module 400 includes AC voltage and frequency control (VF control), AC current and frequency control (FCL control), and active / reactive power control (PQ control). VF control can control the converter traction grid side to output a specified AC voltage, and its input quantities include the output current i T , filter current i HE2 , output voltage u G3 , and the output voltage amplitude command value U* and output voltage phase command value ωt*+θ issued by the system-level control and protection u *(Phase reference comes from GPS or BeiDou satellite positioning system), the output is VF mode modulation voltage u vf The flexible current sharing control in the VF mode can control the multiple converters in the traction station to distribute the output current according to their tolerance ratio. The input quantity is the output current i of each converter in the converter station.T- The output is the converter flexible current sharing control voltage u avr , with u vf 'Add to get the final VF mode modulation voltage u vf FCL control can control the output of a specified AC current on the traction grid side of the converter. Its input quantities include the output current i T , filter current i HE2 , and the output current amplitude command value I* and output current phase command value ωt*+θ issued by the system-level control and protection i *(Phase reference comes from GPS or BeiDou satellite positioning system), the output is FCL mode modulation voltage u fcl ; PQ control can control the output of specified active and reactive power on the traction grid side of the converter. Its input quantity includes output current i T , output voltage u G3 , output voltage phase ωt inv , output active power P inv , output reactive power Q inv , and the output active power command value P* and output reactive power command value Q* issued by the system-level control and protection. The output quantity is the PQ mode modulation voltage u pq According to the target control mode output by the mode discrimination module 200, select u vf 、u fcl 、u pq The corresponding one in the figure is used to obtain the modulation wave u on the traction grid side of the converter. inv *.

[0068] In the embodiment of the present application, the VF control adopts a double closed-loop control structure, the outer loop is AC voltage control, and the inner loop is current lead correction. The control structure is as follows: Figure 6 As shown. In terms of outer loop AC voltage control, the reference voltage u Tref =U*sin(ωt*+θ u *),u Tref Subtract the actual value u G3 Get the voltage error u err , after being limited, is used as the input of the fundamental frequency and harmonic suppression PR controller. The output of the fundamental frequency PR controller is subtracted from the filter current i HE2 Then it is used as the input of the inner loop PR controller. In the flexible current sharing control, the output current reference value i avr * Subtract the output current i T , then multiply by the proportional coefficient k p , and obtain the flexible current sharing control voltage u avr . Set the reference voltage u Tref As the feedforward voltage, it is combined with the output of the inner loop PR controller, the output of the harmonic suppression PR controller, and the dynamic current control voltage uavr The sum is the modulation voltage u in VF mode vf When the VF mode enable signal Mode1Active is 0, the PR link is cleared.

[0069] In the embodiment of the present application, the FCL mode control structure is as follows Figure 7 As shown. Reference current i FCL *=I*sin(ωt*+θ i *), i FCL * Subtract the actual output current i T , as the input of the PR controller. Add a virtual impedance link, the filter current passes through the proportional link, and the difference with the PR controller output is obtained after limiting to obtain the modulation voltage u of the FCL mode. fcl When the FCL mode enable signal Mode3Active is 0, the PR link is cleared.

[0070] In the embodiment of the present application, the PQ control adopts a double closed-loop control structure, the outer loop is active / reactive power control, and the inner loop is AC current control. The control structure is as follows: Figure 8 As shown in the figure, in terms of outer loop active power control, the active power reference value P* on the traction grid side is subtracted from the actual value P inv , as the input of the active PI controller; P* multiplied by √2 and then divided by the rated output voltage U base , as the feedforward of active power control, is added to the output of the active PI controller and the active current reference value i is obtained after amplitude limiting. p_ref Similarly, in terms of outer loop reactive power control, the traction grid side reactive power reference value Q* minus the actual value Q inv , as the input of the reactive PI controller; Q* multiplied by √2 and then divided by the rated output voltage U base , as the feedforward of reactive power control, is added to the output of the reactive PI controller and multiplied by -1 after limiting to obtain the reactive current reference value i q_ref . will i p_ref ,i q_ref As x, y coordinates, after converting to polar coordinates, the amplitude is limited, and then converted back to x, y coordinates to obtain the actual active and reactive current reference values ​​i pref 、i qref .i pref 、i qref Multiply the sine and cosine values ​​of the output voltage respectively, and add them together to get the output current reference value i Tref , minus the actual output current i T Then it is used as the input of the inner loop current PR controller; i pref 、i qref Multiply by the cosine and sine values ​​of the output voltage respectively, and then multiply by the inverter side impedance ωL inv, get the compensation voltage, add the output of the PR controller and the feedforward voltage u G3 , get the modulation voltage u of PQ mode pq When the PQ mode enable signal Mode2Active is 0, the PR link is cleared.

[0071] During actual implementation, the traction network side control module 400 of the embodiment of the present application further includes:

[0072] Active filtering functional unit, used to suppress locomotive characteristic subharmonics;

[0073] Active damping functional unit, used to prevent oscillation of the catenary system.

[0074] Specifically, the traction network side control module can also add other control functions, such as active filtering function to suppress locomotive characteristic subharmonics; active damping function to prevent contact network system oscillation and improve system stability.

[0075] If the converter in the station adopts a modular multilevel converter (MMC) topology, the utility grid-side control module 300 and the traction grid-side control module 400 should also include control functions such as module voltage balancing, phase-to-phase energy balancing, upper and lower bridge arm energy balancing, and circulating current suppression.

[0076] Optionally, in an embodiment of the present application, the sequence control module 500 is used to determine the operating status of the converter station and start or stop the operation of the converter station according to the start and stop process of the converter station.

[0077] Furthermore, the sequential control module 500 is specifically used to determine the operating status of the converter station, including normal operation of the entire station, the exit of some converters from operation, and the exit of the entire station from operation; according to the system-level control sequence instructions and electrical quantities, it controls the start and stop process of the converter station, generates the action signal of the circuit breaker in the converter station, and the unlocking signal of the power devices on the public grid side and the traction grid side of the converter.

[0078] Specifically, the sequence control module 500 is connected to the data acquisition and processing module 100 and is used to control the start and stop process of the converter station. Figure 9 This is a start-stop flow chart of a through-phase traction power supply converter station provided according to an embodiment of the present application. Figure 9As shown, the startup process when the contact network is not energized includes: issuing a startup command, switching the switch cabinet according to the status of the circuit breaker 106 / 107, operating the three-position switch, closing the circuit breaker 60GT / 70GT, unlocking the pulse on the public grid side of the converter, closing the circuit breaker 60G, unlocking the pulse on the traction grid side of the converter, and connecting to the grid. When the contact network is energized, the traction grid side pulse is first unlocked to establish the voltage, and then the circuit breaker 60G is controlled to close synchronously. The shutdown process includes: issuing a shutdown command, locking the pulses on the traction grid side and the public grid side of the converter, disconnecting the current public grid side circuit breaker 60GT / 70GT, disconnecting the circuit breaker 60G, operating the three-position switch, and completing the shutdown. When some converters in the converter station are started or shut down, it is only necessary to unlock the corresponding converter pulses and close or disconnect the circuit breaker inside the converter, and there is no need to complete the entire start-stop process. The input quantity of the sequential control module 500 includes the average value of the valve group voltage u Davr , as well as the sequential control instructions issued by the system-level control. The output quantities include the converter unlocking signal and the I / O instructions issued to the valve base control.

[0079] Optionally, in an embodiment of the present application, the modulation module 600 is used to modulate the first modulation wave on the public grid side of the converter and the second modulation wave on the traction grid side of the converter to generate a trigger pulse, and generate a valve base control signal from the trigger pulse.

[0080] Specifically, the modulation module 600 is connected to the public network side control module 300, the traction network side control module 400 and the sequence control module 500, and is used to modulate the modulation wave on the public network side and the traction network side. The input includes the converter unlocking signal, the public network side modulation wave u rec *, traction network side modulation wave u inv *, the output is the trigger pulse, which is sent to the valve base control.

[0081] According to the through-phase co-phase traction power supply substation-level control system proposed in the embodiment of the present application, a complete technical solution applicable to the through-phase co-phase traction power supply substation-level control system is provided, including a complete process of data acquisition and processing, sequential control, mode discrimination, public grid side and traction grid side control, and modulation. On the basis of realizing power conversion between the three-phase external power grid and the single-phase traction power grid, the appropriate operating mode can be switched according to different operating conditions of the system, and various additional functions such as reactive power compensation, active filtering, active damping, etc. can also be realized, giving full play to the safety, stability and economic advantages of the through-phase co-phase traction power supply system.

[0082] Next, a through-phase traction power supply converter station-level control method proposed according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0083] Figure 10 This is a flow chart of a through-phase traction power supply converter station-level control method provided according to an embodiment of the present application.

[0084] like Figure 10 As shown, the through-cophase traction power supply converter station-level control method utilizes the through-cophase traction power supply converter station-level control system of the above embodiment, and the method includes the following steps:

[0085] Step S101 : collecting electrical data of the converter and processing the electrical data to obtain electrical quantities of the converter.

[0086] Step S102: determining a target control mode of the traction network side of the converter according to the system-level control instruction and the electrical quantity.

[0087] Optionally, in an embodiment of the present application, the target control mode of the traction network side of the converter is determined based on the system-level control instructions and electrical quantities, including: when it is judged based on the electrical quantities that a contact network short-circuit fault has occurred in the system, the target control mode of the traction network side of the converter is determined to be an AC current and frequency control mode; when it is judged that no contact network short-circuit fault has occurred in the system, the target control mode of the traction network side of the converter is determined to be the control mode in the system-level control instructions.

[0088] Optionally, in an embodiment of the present application, whether a contact network short circuit fault has occurred in the system is determined based on electrical quantities, including: when the output side current of the converter is greater than a threshold current, and the duration of being greater than the threshold current is greater than a first preset time length, it is determined that a contact network short circuit fault has occurred in the system; when the output voltage of the converter is greater than a threshold voltage, and the duration of being greater than the threshold voltage is greater than a second preset time length, it is determined that the contact network short circuit fault of the system has been eliminated.

[0089] Step S103, according to the system-level control sequence instructions and electrical quantities, the start and stop process of the converter station is controlled, and the action signal of the circuit breaker in the converter station and the unlocking signal of the power devices on the utility side and the traction network side of the converter are generated.

[0090] Step S104 : Control the public grid side of the converter according to the electrical quantity, and output a first modulation wave of the public grid side of the converter.

[0091] Step S105 , after the traction network side of the converter is controlled to enter the target control mode, the traction network side of the converter is controlled according to the electrical quantity, and a second modulation wave of the traction network side of the converter is output.

[0092] Step S106 , modulating the first modulation wave on the utility grid side of the converter and the second modulation wave on the traction grid side of the converter to generate a trigger pulse, and generating a valve base control signal from the trigger pulse.

[0093] The following describes a station-level control method for the through-phase traction power supply of an embodiment of the present application through a specific embodiment.

[0094] 1) Collect the voltage and current signals in the converter, and process and calculate them to obtain the signals required by each control module.

[0095] 2) The operating mode of the converter is determined based on the control mode instructions issued by the system-level control and the collected voltage and current signals. Under normal operating conditions, the control mode of the traction network side follows the control mode instructions issued by the system-level control, and the mode of the collected voltage and current signals is judged to determine whether the converter enters the FCL mode.

[0096] 3) Based on the sequential control instructions issued by the system-level control and the collected voltage and current signals, the start and stop processes of the converter are controlled, and the action signals of the circuit breaker in the converter and the unlocking signals of the power devices on the public grid and traction grid sides are generated.

[0097] 4) The signals acquired and processed and the control mode instructions on the traction network side are fed into the control modules on the public network side and the traction network side to obtain the modulation signals on the public network side and the traction network side.

[0098] 5) Under the condition that the power devices are unlocked, the modulation signals on the public grid side and the traction grid side are modulated to obtain power device trigger pulses, thereby driving the power devices contained in the converter to turn on and off.

[0099] It should be noted that the above explanation of the embodiment of the through-cophase traction power supply converter station-level control system is also applicable to the through-cophase traction power supply converter station-level control method of this embodiment, and will not be repeated here.

[0100] According to the through-phase co-phase traction power supply converter station-level control method proposed in the embodiment of the present application, the electrical data of the converter is collected in real time and processed to obtain the electrical quantity of the converter. The target control mode of the converter's traction network side is determined according to the system-level control instructions and the electrical quantity. The public network side of the converter is controlled according to the electrical quantity, and the first modulation wave of the public network side of the converter is output. After the traction network side of the converter is controlled to enter the target control mode, the traction network side of the converter is controlled according to the electrical quantity, and the second modulation wave of the traction network side of the converter is output. The first modulation wave of the public network side of the converter and the second modulation wave of the traction network side of the converter are modulated to generate a trigger pulse, and the trigger pulse generates a valve base control signal. In this way, through-phase co-phase traction power supply converter station-level control is achieved.

[0101] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. 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 N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0102] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0103] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0104] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0105] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related 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 embodiment.

Claims

1. A through-phase traction power supply converter station-level control system, characterized in that: include: A data acquisition and processing module is used to acquire the electrical data of the converter in real time and process the electrical data to obtain the electrical quantities of the converter; a mode discrimination module, configured to determine a target control mode on the traction network side of the converter based on a system-level control instruction and the electrical quantity, wherein the mode discrimination module is further configured to, when it is determined based on the electrical quantity that a contact network short-circuit fault has occurred in the system, determine that the target control mode on the traction network side of the converter is an AC current and frequency control mode; and when it is determined that no contact network short-circuit fault has occurred in the system, determine that the target control mode on the traction network side of the converter is the control mode in the system-level control instruction; a public grid side control module, configured to control the public grid side of the converter according to the electrical quantity and output a first modulation wave of the public grid side of the converter; a traction network side control module, configured to control the traction network side of the converter to enter the target control mode, and then control the traction network side of the converter according to the electrical quantity, and output a second modulated wave of the traction network side of the converter, wherein the traction network side control module includes: an AC voltage and frequency control unit, configured to control the traction network side of the converter to output a set AC voltage, thereby realizing flexible current sharing of multiple converters in the station; an AC current and frequency control unit, configured to control the traction network side of the converter to output a set AC current; an active / reactive power control unit, configured to control the traction network side of the converter to output a set active and reactive power; and an output unit, configured to select one of the AC voltage and frequency control unit, the AC current and frequency control unit, and the active / reactive power control unit according to the target control mode determined by the mode discrimination module, to control the traction network side of the converter, thereby outputting the second modulated wave of the traction network side of the converter; A sequence control module, configured to determine the operating status of a converter station and start or stop the operation of the converter station according to the start and stop process of the converter station; and The modulation module is used to modulate the first modulation wave on the public grid side of the converter and the second modulation wave on the traction grid side of the converter to generate a trigger pulse, and generate a valve base control signal from the trigger pulse.

2. The system according to claim 1, wherein: The traction network side control module further includes: Active filtering functional unit, used to suppress locomotive characteristic subharmonics; Active damping functional unit, used to prevent oscillation of the catenary system.

3. The system according to claim 1, wherein: The mode discrimination module is further used to: When the current at the output side of the converter is greater than a threshold current and the duration of the current being greater than the threshold current is greater than a first preset time length, it is determined that a contact network short circuit fault occurs in the system; When the output voltage of the converter is greater than the threshold voltage and the duration of the output voltage being greater than the threshold voltage is greater than a second preset duration, it is determined that the contact network short-circuit fault of the system has been eliminated.

4. The system according to claim 3, characterized in that The mode identification module is further used to determine that the target control mode on the traction network side of the converter is the active / reactive power control mode when the power of the converter station reaches the total tolerance of the equipment in the station under the AC voltage and frequency control mode, and after receiving the recovery instruction issued by the system-level control, determine that the target control mode on the traction network side of the converter returns to the AC voltage and frequency control mode.

5. The system according to claim 1, wherein: The public network side control module includes: A DC voltage control unit, used to control the converter valve group to maintain a set DC voltage; The reactive power control unit is used to control the reactive power set by the public grid side input of the converter.

6. The system according to claim 1, wherein: The sequential control module is further used to determine the operating status of the converter station, including normal operation of the entire station, the exit of some converters from operation, and the exit of the entire station from operation; according to the system-level control sequence instructions and the electrical quantities, control the start and stop process of the converter station, generate the action signal of the circuit breaker in the converter station, and the unlocking signal of the power devices on the public grid side and the traction grid side of the converter.

7. A through-phase traction power supply converter station-level control method, characterized in that: The through-cophase traction power supply converter station-level control system according to any one of claims 1 to 6 is used, wherein the method comprises the following steps: collecting electrical data of the converter and processing the electrical data to obtain electrical quantities of the converter; Determining a target control mode of the traction network side of the converter according to the system-level control instruction and the electrical quantity, wherein determining the target control mode of the traction network side of the converter according to the system-level control instruction and the electrical quantity includes: when it is determined according to the electrical quantity that a contact network short-circuit fault occurs in the system, determining that the target control mode of the traction network side of the converter is an AC current and frequency control mode; when it is determined that the contact network short-circuit fault does not occur in the system, determining that the target control mode of the traction network side of the converter is the control mode in the system-level control instruction; Controlling the start and stop process of the converter according to the system-level control sequence instruction and the electrical quantity, generating an actuation signal of a circuit breaker in the converter, and an unlocking signal of power devices on the utility grid side and the traction grid side of the converter; Controlling the public grid side of the converter according to the electrical quantity, and outputting a first modulated wave of the public grid side of the converter; After controlling the traction network side of the converter to enter the target control mode, the traction network side of the converter is controlled according to the electrical quantity to output a second modulation wave of the traction network side of the converter; and The first modulation wave on the public grid side of the converter and the second modulation wave on the traction grid side of the converter are modulated to generate a trigger pulse, and a valve base control signal is generated from the trigger pulse.

Images