Weak power grid high-adaptability control system and method for train converter

Abstract

The invention discloses a weak power grid high-adaptability control system and method for a train converter. The weak power grid high-adaptability control system comprises a sensor, a traction converter circuit and a control device. The sensor used for measuring the operation state of the traction converter circuit is arranged in the traction converter circuit; the control device used for acquiring the running state measured by the sensor and controlling the traction conversion of the rail transit train is connected with the traction conversion circuit through the sensor; according to the system, the sensor is arranged in the traction converter circuit, the operation state measured by the sensor is obtained through the control system, rail transit train traction conversion control is carried out, and the reactive power of the system can be dynamically compensated by controlling the vehicle-mounted traction converter; a network voltage drop phenomenon caused by a low-capacity traction power grid under a high-power traction working condition of the train is inhibited; the method has the same beneficial effects.

Description

Technical Field

[0001] The present application relates to the field of rail transit traction inverter technology, and in particular to a highly adaptable control system and method for a weak power grid of a train inverter. Background Art

[0002] With the continuous development of my country's economy, the demand for railway transportation volume is growing, and the traction load power is increasing. However, due to its infrastructure characteristics, it is difficult to make adaptive improvements to the railway traction power supply system in the short term, resulting in the increasingly prominent capacity mismatch problem between multiple high-power rail transit trains and the traction power grid. At the end of the traction power supply arm, due to the dual effects of the low-capacity traction grid and the high-power traction load, the grid voltage drops and the current phase hysteresis problems are caused. The voltage drop of the traction grid will reduce the efficiency of the traction power supply system, cause overcurrent in the traction drive system, and even trigger train protection, seriously endangering the safe and stable operation of the vehicle-grid system.

[0003] To address the voltage drop problem of the power supply arm in low-capacity traction power grids, existing solutions include ground compensation and on-board compensation. For the ground compensation solution, it needs to be configured at multiple locations along the line, with high initial investment and operation and maintenance costs, and it is impossible to compensate for reactive power in real time, and the switching operation will interfere with the stability of the system. For the on-board compensation solution, there is a lack of mature and practical reactive power command generation logic and real-time control methods for dynamic reactive power compensation of the grid-side converter.

[0004] In view of this, it is a technical problem that technicians in this field need to urgently solve to provide a weak grid high adaptability control system and method for a train converter that improves the adaptability to a low-capacity traction grid from the perspective of the train itself. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a highly adaptable control system and method for a weak power grid of a train inverter, which can dynamically compensate for the reactive power of the system by controlling the on-board traction inverter, and suppress the grid voltage drop phenomenon caused by the low-capacity traction grid in the high-power traction condition of the train.

[0006] The first object of the present invention is to provide a highly adaptable control system for a weak power grid of a train converter; The technical solution provided by the present invention is as follows: A highly adaptable weak power grid control system for a train converter, comprising: a sensor, a traction converter circuit and a control device; The sensor is arranged in the traction converter circuit; The control device is connected to the traction converter circuit via the sensor; The sensor is used to measure the operating state of the traction converter circuit; The control device is used to obtain the operating status measured by the sensor and control the traction converter of the rail transit train.

[0007] Preferably, the traction converter circuit comprises: a pantograph, a circuit breaker, a traction transformer, a four-quadrant converter, a DC link, a traction inverter, a traction motor, a bidirectional chopper and an on-board energy storage; The circuit breaker is connected to the pantograph and the traction transformer respectively; The traction transformer is connected to the four-quadrant converter via a contactor; The four-quadrant converter is connected to the traction inverter via the DC link; The traction inverter is connected to the traction motor and the bidirectional chopper respectively; The bidirectional chopper is connected to the on-board energy storage.

[0008] Preferably, the sensor comprises: a grid-side voltage transformer, a grid-side current transformer, a four-quadrant current sensor and a DC voltage sensor; The grid-side voltage transformer is connected to the pantograph; The grid-side current transformer is connected to the circuit breaker and the traction transformer respectively; The four-quadrant current sensor is connected to the traction transformer and the four-quadrant converter respectively; The DC voltage sensor is connected to the four-quadrant converter and the traction inverter respectively.

[0009] Preferably, the control device comprises: an operation status monitoring module, a grid-side reactive current extraction module, a reactive current tolerance calculation module, a reactive current instruction generation module, a dynamic reactive current compensation control module and a traction current conversion control module; The operation status monitoring module is respectively connected to the sensor, the grid-side reactive current extraction module, the reactive current tolerance calculation module and the reactive current instruction generation module; The grid-side reactive current extraction module is connected to the dynamic reactive current compensation control module; The reactive current tolerance calculation module is connected to the reactive current instruction generation module; The reactive current instruction generation module is connected to the dynamic reactive current compensation control module; The dynamic reactive current compensation control module is connected to the traction current conversion control module; The operation status monitoring module is used to obtain the grid voltage status signal, the grid-side current signal and the train operation condition data through the sensor; The grid-side reactive current extraction module is used to calculate the reactive component of the grid-side current in real time according to the grid voltage state signal and the grid-side current signal; The reactive current tolerance calculation module is used to calculate the maximum reactive current tolerance of the current traction converter in real time according to the grid voltage state signal and the grid-side current signal; The reactive current instruction generation module is used to calculate the reactive current control reference signal for the grid voltage support function in real time according to the grid voltage state signal, the grid-side current signal and the maximum reactive current tolerance; The dynamic reactive current compensation control module is used to track the reactive current control reference signal in real time; The traction current conversion control module is used to compensate for the grid voltage, suppress grid-side current harmonics, stabilize the DC voltage, and control the traction motor.

[0010] The second object of the present invention is to provide a highly adaptable control method for a weak power grid of a train converter; The technical solution provided by the present invention is as follows: A method for controlling a weak power grid with high adaptability of a train converter, based on the weak power grid with high adaptability control system of the train converter according to claims 1 to 4, comprises the following steps: In the program initialization stage, write the rail transit train traction characteristic curve and the maximum reactive current tolerance value; Get the effective value of the grid voltage at the pantograph; Generate a reactive current instruction according to the rail transit train traction characteristic curve, the maximum reactive current tolerance value and the effective value of the grid voltage at the pantograph; The dynamic reactive power compensation real-time control strategy is executed through the reactive current instruction to control the operation of the train converter.

[0011] Preferably, in the program initialization stage, writing the rail transit train traction characteristic curve and the maximum reactive current tolerance value specifically includes: During the program initialization phase, the rail transit train traction characteristic curve and the maximum reactive current tolerance value are written into the reactive current instruction generation module.

[0012] Preferably, in the program initialization stage, writing the rail transit train traction characteristic curve specifically includes: The rail transit train traction characteristic curve is written to obtain compensation voltage threshold 1 and compensation voltage threshold 2.

[0013] Preferably, the compensation voltage threshold 1 corresponds to the voltage lower limit value of the train output rated power range in the traction characteristic curve; the compensation threshold 2 corresponds to the lowest continuous voltage value in the traction characteristic curve.

[0014] Preferably, generating a reactive current instruction according to the rail transit train traction characteristic curve, the maximum reactive current tolerance value and the effective value of the grid voltage at the pantograph specifically includes: A reactive current instruction is generated according to the compensation voltage threshold 1, the compensation voltage threshold 2 and the effective value of the grid voltage at the pantograph.

[0015] Preferably, generating a reactive current instruction according to the compensation voltage threshold 1, the compensation voltage threshold 2 and the effective value of the grid voltage at the pantograph specifically includes: When the effective value of the grid voltage at the pantograph is greater than or equal to the compensation voltage threshold 1, there is no need to compensate the traction grid voltage, and at this time the reactive current command is 0; When the effective value of the grid voltage at the pantograph is less than the compensation voltage threshold 1 and greater than or equal to the compensation voltage threshold 2, the traction grid voltage needs to be compensated, and at this time the reactive current instruction is between 0 and the maximum allowable reactive current corresponding to the compensation voltage threshold 2; When the effective value of the grid voltage at the pantograph is less than the compensation voltage threshold 2, the traction grid voltage needs to be compensated to the maximum extent, and at this time, the reactive current instruction is the maximum reactive current tolerance value.

[0016] Preferably, obtaining the effective value of the grid voltage at the pantograph specifically includes: After the voltage signal collected by the grid voltage transformer is digitally filtered, the effective value of the grid voltage at the pantograph is calculated by a preset method.

[0017] Preferably, the dynamic reactive power compensation real-time control strategy is generated by: On the basis of the basic control strategy of the four-quadrant converter on the rail transit train network side, a reactive power compensation link is added to form the dynamic reactive power compensation real-time control strategy; Wherein, the instructions of the reactive power compensation link are generated by a reactive power instruction generation module.

[0018] Preferably, the executing of the dynamic reactive compensation real-time control strategy through the reactive current instruction to control the operation of the train converter specifically includes: The reactive power instruction generation module generates the grid-side reactive power compensation component reference value ; Set the DC voltage reference value Real-time value of DC voltage The grid-side active component reference value is obtained through the PI controller ; The grid-side reactive compensation component reference value and grid-side active component reference value The current components are compared with the grid-side reactive current component and the grid-side active current component, and a modulation reference wave is generated through the PI controller. ; The modulated reference wave Generate a switching pulse signal through a carrier modulation algorithm; The operation of the train converter is controlled according to the switch pulse signal.

[0019] The third object of the present invention is to provide an electronic device; The technical solution provided by the present invention is as follows: An electronic device, comprising: at least one processor; and A memory communicatively connected to the at least one processor, the memory storing a computer program executable by the at least one processor, the computer program being executed by the at least one processor so that the at least one processor can perform the method steps described in the method for highly adaptable weak power grid control of a train converter.

[0020] A fourth object of the present invention is to provide a computer readable storage medium; The technical solution provided by the present invention is as follows: A computer-readable storage medium is used to store a computer program, and the computer program is used to enable a computer to execute the method steps described in the method for highly adaptable weak power grid control of a train converter.

[0021] The present invention provides a highly adaptable control system for a weak power grid of a train converter, comprising: a sensor, a traction converter circuit and a control device; the sensor is arranged in the traction converter circuit; the control device is connected to the traction converter circuit through the sensor; the sensor is used to measure the operating state of the traction converter circuit; the control device is used to obtain the operating state measured by the sensor and control the traction converter of a rail transit train; the system sets a sensor in the traction converter circuit, then obtains the operating state measured by the sensor through a control system, and performs traction converter control on the rail transit train, and can dynamically compensate for system reactive power by controlling the on-board traction converter, thereby suppressing the network voltage drop phenomenon caused by a low-capacity traction power grid under high-power traction conditions of the train.

[0022] The present invention also provides a weak power grid high adaptability control method for a train converter. Since this method solves the same technical problem as the weak power grid high adaptability control system of the train converter and belongs to the same technical concept, it should have the same beneficial effects and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of the structure of a weak power grid high adaptability control system for a train converter provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of another highly adaptable control system for a weak power grid of a train converter provided by an embodiment of the present invention; Figure 3 A schematic diagram of the structure of a control device provided by an embodiment of the present invention; Figure 4 A flow chart of a method for controlling a train converter in a weak power grid with high adaptability provided by an embodiment of the present invention; Figure 5 A flow chart of reactive current instruction generation provided by an embodiment of the present invention; Figure 6 A schematic diagram of the structure of a dynamic reactive power compensation real-time control strategy provided in an embodiment of the present application; Figure 7 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] It should be noted that when an element is referred to as being "fixed on" or "set on" another element, it can be directly on the other element or indirectly set on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0027] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" and "several" mean two or more, unless otherwise clearly and specifically defined.

[0029] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the effects and purposes that can be achieved by this application.

[0030] like Figure 1 to Figure 2 As shown, an embodiment of the present invention provides a highly adaptable control system for a weak power grid of a train converter, comprising: a sensor 1, a traction converter circuit 2 and a control device 3; The sensor 1 is arranged in the traction converter circuit 2; The control device 3 is connected to the traction converter circuit 2 via the sensor 1; The sensor 1 is used to measure the operating state of the traction converter circuit 2; The control device 3 is used to obtain the operating status measured by the sensor 1 and control the traction current conversion of the rail transit train.

[0031] In actual use, when the low-capacity traction grid matches the high-power train load, the grid voltage drop problem is prone to occur at the end of the line. Therefore, a sensor is set in the traction inverter circuit to measure the operating status of the traction inverter circuit, and then a control system is set to connect with the sensor to facilitate the operation status of the traction inverter circuit through the sensor. Then, the traction inverter of the road traffic train is controlled to enable the train to have the ability to actively support the grid voltage, thereby improving the train's adaptability to the low-capacity traction grid.

[0032] Preferably, the traction converter circuit 2 comprises: a pantograph 21, a circuit breaker 22, a traction transformer 23, a four-quadrant converter 24, a DC link 25, a traction inverter 26, a traction motor 27, a bidirectional chopper 28 and an on-board energy storage 29; The circuit breaker 22 is connected to the pantograph 21 and the traction transformer 23 respectively; The traction transformer 23 is connected to the four-quadrant converter 24 via a contactor; The four-quadrant converter 24 is connected to the traction inverter 26 via the DC link 25; The traction inverter 26 is connected to the traction motor 27 and the bidirectional chopper 28 respectively; The bidirectional chopper 28 is connected to the on-board energy storage 29 .

[0033] In actual use, the above-mentioned devices are used to form the main circuit of the traction conversion system of the rail transit train. Among them, on-board energy storage equipment is installed in the main circuit of the traction conversion system of the rail transit train. The on-board energy storage equipment can participate in the reactive current tolerance calculation and dynamic reactive current compensation control as a backup capacity, thereby increasing the traction conversion system's support capacity for the traction grid voltage.

[0034] Preferably, the sensor 1 comprises: a grid-side voltage transformer 11, a grid-side current transformer 12, a four-quadrant current sensor 13 and a DC voltage sensor 14; The grid-side voltage transformer 11 is connected to the pantograph 21; The grid-side current transformer 12 is connected to the circuit breaker 22 and the traction transformer 23 respectively; The four-quadrant current sensor 13 is connected to the traction transformer 23 and the four-quadrant current converter 24 respectively; The DC voltage sensor 14 is connected to the four-quadrant converter 24 and the traction inverter 26 respectively.

[0035] In actual application, the sensors include grid-side voltage transformer, grid-side current transformer, four-quadrant current sensor and DC voltage sensor, and they are set in the main circuit of the traction converter system of the rail transit train; the grid-side voltage transformer is used to measure the grid-side voltage of the traction transformer; the grid-side current transformer is used to measure the grid-side current of the traction transformer; the four-quadrant current sensor is used to measure the AC side current of the four-quadrant converter; the DC voltage sensor is used to measure the DC side voltage of the four-quadrant converter.

[0036] Preferably, the control device 3 comprises: an operation status monitoring module 31, a grid-side reactive current extraction module 32, a reactive current tolerance calculation module 33, a reactive current instruction generation module 34, a dynamic reactive current compensation control module 35 and a traction current conversion control module 36; The operation status monitoring module 31 is respectively connected to the sensor 2, the grid-side reactive current extraction module 32, the reactive current tolerance calculation module 33 and the reactive current instruction generation module 34; The grid-side reactive current extraction module 32 is connected to the dynamic reactive current compensation control module 35; The reactive current tolerance calculation module 33 is connected to the reactive current instruction generation module 34; The reactive current instruction generation module 34 is connected to the dynamic reactive current compensation control module 35; The dynamic reactive current compensation control module 35 is connected to the traction current conversion control module 36; The operation status monitoring module 31 is used to obtain the grid voltage status signal, the grid-side current signal and the train operation condition data through the sensor 1; The grid-side reactive current extraction module 32 is used to calculate the grid-side current reactive component in real time according to the grid voltage state signal and the grid-side current signal; The reactive current tolerance calculation module 33 is used to calculate the maximum reactive current tolerance of the current traction converter in real time according to the grid voltage state signal and the grid-side current signal; The reactive current instruction generating module 34 is used to calculate the reactive current control reference signal for the grid voltage support function in real time according to the grid voltage state signal, the grid-side current signal and the maximum reactive current tolerance; The dynamic reactive current compensation control module 35 is used to track the reactive current control reference signal in real time; The traction current conversion control module 36 is used to compensate the grid voltage, suppress grid-side current harmonics, stabilize the DC voltage and control the traction motor.

[0037] In actual use, the control device is a low-capacity weak grid voltage active support control system, such as Figure 3As shown, a running state monitoring module, a grid-side reactive current extraction module, a reactive current tolerance calculation module, a reactive current instruction generation module, a dynamic reactive current compensation control module and a traction converter control module are set up. The function of the running state monitoring module is mainly to obtain the grid voltage state signal, the grid-side current signal and the train running condition data through sensors; the grid-side reactive current extraction module calculates the reactive component of the grid-side current in real time according to the signal provided by the running state monitoring module through methods such as dq current decoupling and reactive current digital filtering extraction; the reactive current tolerance calculation module calculates the maximum reactive current tolerance that the current traction converter can play in real time according to the signal provided by the running state monitoring module, with the purpose of ensuring the normal traction operation of the train and the safety of the traction converter system. The reactive current tolerance calculation method in the reactive current tolerance calculation module refers to comprehensively considering various operating conditions and safety boundary conditions to obtain The upper limit of reactive power compensation command for each working condition mainly includes the following restrictions: traction converter power restriction, traction transformer power restriction, traction motor power restriction, grid-side power factor restriction, modulation depth and switch dead zone restriction, etc., so as to ensure the normal traction power of rail transit trains and the safety of traction conversion system while performing dynamic reactive power compensation; the reactive current command generation module integrates the signal provided by the operation status monitoring module and the maximum reactive current tolerance, and calculates the reactive current control reference signal for grid voltage support function in real time through the comprehensive reactive current command generation method; the dynamic reactive current compensation control module is used for real-time and accurate tracking of reactive current control reference signal by the reactive component of grid-side current; the traction conversion control module combines dynamic reactive current compensation control with conventional traction conversion control, and realizes grid voltage compensation, grid-side current harmonic suppression, DC voltage stability, traction motor control and other functions at the same time.

[0038] like Figure 4 As shown, an embodiment of the present invention provides a method for controlling a weak power grid with high adaptability of a train converter, based on the weak power grid with high adaptability control system of the train converter according to claims 1 to 4, comprising the following steps: S1. In the program initialization stage, write the rail transit train traction characteristic curve and the maximum reactive current tolerance value; In step S1, during the program initialization phase, the rail transit train traction characteristic curve and the maximum reactive current tolerance value are written; wherein, the maximum reactive current tolerance value is obtained by the reactive current tolerance calculation module; the rail transit train traction characteristic curve specifies the maximum power allowed by the train traction system under different traction network voltages, which is used to ensure the safety of the traction system.

[0039] S2. Obtain the effective value of the grid voltage at the pantograph; In step S2, the effective value of the grid voltage at the pantograph is obtained through real-time calculation.

[0040] S3. Generate a reactive current instruction according to the rail transit train traction characteristic curve, the maximum reactive current tolerance value and the effective value of the grid voltage at the pantograph; In step S3, the effective value of the grid voltage at the pantograph is compared with the traction characteristic curve of the rail transit train in real time to select the reactive current instruction generation method to generate the reactive current instruction. The reactive current instruction does not require the calculation of line impedance or ground coordination, and the reactive power is maximized to support the traction grid voltage while ensuring the basic traction power requirements and hardware carrying capacity of the train.

[0041] S4. Execute the dynamic reactive power compensation real-time control strategy through the reactive current instruction to control the operation of the train converter.

[0042] In step S4, a dynamic reactive compensation real-time control strategy based on dq current decoupling control based on coordinate transformation is executed according to the reactive current instruction generated in step S3, and then the operation of the train inverter is controlled according to the dynamic reactive compensation real-time control strategy, so that the rail transit train can support the traction grid voltage through active reactive compensation while ensuring normal traction operation under the condition of weak grid and low grid voltage, without relying on the transformation of the traction power supply system and the installation of compensation devices, so as to improve the adaptability of the rail transit train to the low-capacity traction grid from the perspective of the rail transit train itself, and improve the operation limit of the rail transit train under the extreme condition of weak grid and heavy load.

[0043] Preferably, in the program initialization stage, writing the rail transit train traction characteristic curve and the maximum reactive current tolerance value specifically includes: During the program initialization phase, the rail transit train traction characteristic curve and the maximum reactive current tolerance value are written into the reactive current instruction generation module.

[0044] In actual application, during the program initialization phase, the rail transit train traction characteristic curve and the maximum reactive current tolerance value are written into the reactive current instruction generation module; this is parallel to step S2, and both are preparations for subsequent steps.

[0045] Preferably, in the program initialization stage, writing the rail transit train traction characteristic curve specifically includes: The rail transit train traction characteristic curve is written to obtain compensation voltage threshold 1 and compensation voltage threshold 2.

[0046] In actual application, the traction characteristic curve of the rail transit train is written to obtain the compensation voltage threshold 1 and the compensation voltage threshold 2, wherein the compensation voltage threshold 1 corresponds to the voltage lower limit value of the train output rated power range in the traction characteristic curve; the compensation threshold 2 corresponds to the minimum continuous voltage value in the traction characteristic curve; taking the traction characteristic curve specified in the "Rail Transit Traction Power Supply System Voltage" as an example, the compensation voltage threshold 1 is 22.5kV, and the compensation voltage threshold 2 is 19kV.

[0047] Preferably, generating a reactive current instruction according to the rail transit train traction characteristic curve, the maximum reactive current tolerance value and the effective value of the grid voltage at the pantograph specifically includes: A reactive current instruction is generated according to the compensation voltage threshold 1, the compensation voltage threshold 2 and the effective value of the grid voltage at the pantograph.

[0048] In actual use, the effective value of the grid voltage at the pantograph is compared with the compensation voltage threshold 1 and the compensation voltage threshold 2 in real time, so as to select the generation method of the reactive current command to generate the reactive current command.

[0049] Preferably, generating a reactive current instruction according to the compensation voltage threshold 1, the compensation voltage threshold 2 and the effective value of the grid voltage at the pantograph specifically includes: When the effective value of the grid voltage at the pantograph is greater than or equal to the compensation voltage threshold 1, there is no need to compensate the traction grid voltage, and at this time the reactive current command is 0; When the effective value of the grid voltage at the pantograph is less than the compensation voltage threshold 1 and greater than or equal to the compensation voltage threshold 2, the traction grid voltage needs to be compensated, and at this time, the reactive current instruction is between 0 and the maximum allowable reactive current corresponding to the compensation voltage threshold 2; When the effective value of the grid voltage at the pantograph is less than the compensation voltage threshold 2, the traction grid voltage needs to be compensated to the maximum extent, and at this time, the reactive current instruction is the maximum reactive current tolerance value.

[0050] In actual application, Figure 5 As shown in the figure, when the effective value of the grid voltage at the pantograph is greater than or equal to the compensation voltage threshold 1, there is no need to compensate the traction grid voltage, and the reactive current command is 0 at this time; when the effective value of the grid voltage at the pantograph is less than the compensation voltage threshold 1 and greater than or equal to the compensation voltage threshold 2, the traction power of the rail transit train is limited, and the traction grid voltage needs to be compensated. At this time, the reactive current command changes linearly from 0 to the maximum allowable reactive current corresponding to the compensation voltage threshold 2 according to the effective value of the grid voltage; when the effective value of the grid voltage at the pantograph is lower than the compensation voltage threshold 2, the traction power of the rail transit train will be severely limited, and the traction grid voltage needs to be compensated to the maximum extent. At this time, the reactive current command is the maximum reactive current tolerance value.

[0051] Preferably, obtaining the effective value of the grid voltage at the pantograph specifically includes: After the voltage signal collected by the grid voltage transformer is digitally filtered, the effective value of the grid voltage at the pantograph is calculated by a preset method.

[0052] In actual application, after digital filtering of the voltage signal collected by the grid voltage transformer, the effective value of the grid voltage at the pantograph can be calculated by the absolute value digital filtering method or the sliding window period mean square method.

[0053] Preferably, the dynamic reactive power compensation real-time control strategy is generated in the following manner: On the basis of the basic control strategy of the four-quadrant converter on the rail transit train network side, a reactive power compensation link is added to form the dynamic reactive power compensation real-time control strategy; Wherein, the instructions of the reactive power compensation link are generated by a reactive power instruction generation module.

[0054] In actual application, the real-time control strategy of dynamic reactive power compensation is to add a reactive power compensation link on the basis of the basic control strategy of the four-quadrant converter on the network side of the rail transit train. The instructions of the reactive power compensation link are generated by the reactive power instruction generation module; and the basic control strategy of the four-quadrant converter on the network side of the rail transit train refers to a four-quadrant control method with the function of grid-side reactive current extraction, including but not limited to: dq current decoupling control based on coordinate transformation, transient current control based on digital filtering reactive power extraction, model prediction current control and direct active-reactive power control.

[0055] Preferably, the executing of the dynamic reactive compensation real-time control strategy through the reactive current instruction to control the operation of the train converter specifically includes: The reactive power instruction generation module generates the grid-side reactive power compensation component reference value ; Set the DC voltage reference value Real-time value of DC voltage The grid-side active component reference value is obtained through the PI controller ; The grid-side reactive compensation component reference value and grid-side active component reference value The current components are compared with the grid-side reactive current component and the grid-side active current component, and a modulation reference wave is generated through the PI controller. ; The modulated reference wave Generate a switching pulse signal through a carrier modulation algorithm; The operation of the train converter is controlled according to the switch pulse signal.

[0056] In actual application, the real-time control strategy of dynamic reactive power compensation based on dq current decoupling control based on coordinate transformation is as follows: Figure 6 As shown, and are the components of the grid-side current in the stationary coordinate system, and They are the components of the grid-side current in the rotating coordinate system, namely the active component and the reactive component; the reactive instruction generation module generates the reference value of the reactive compensation component on the grid side ; DC voltage reference value Real-time value of DC voltage The grid-side active component reference value is obtained through the PI controller , where the DC voltage reference value is the set value determined after the traction system is designed; the DC voltage real-time value is the DC voltage value measured by the DC voltage sensor. Both the DC voltage reference value and the DC voltage real-time value are the values ​​that the maximum reactive current tolerance calculation module needs to collect in order to calculate the maximum reactive current tolerance; then the grid-side reactive compensation component reference value and grid-side active component reference value The current components are compared with the grid-side reactive current component and the grid-side active current component, and a modulation reference wave is generated through the PI controller. ; Finally, the switching pulse signal is generated through the carrier modulation algorithm to control the operation of the converter.

[0057] Furthermore, the present application also discloses an electronic device. Figure 7 This is a structural diagram of an electronic device 20 according to an exemplary embodiment. The content in the diagram cannot be regarded as any limitation on the scope of use of the present application.

[0058] Figure 7 A schematic diagram of the structure of an electronic device 20 provided in an embodiment of the present application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 is used to store a computer program, which is loaded and executed by the processor 21 to implement the relevant steps in the weak power grid high adaptability control method of the train converter disclosed in any of the aforementioned embodiments. In addition, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0059] In this embodiment, the power supply 23 is used to provide working voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and the external device, and the communication protocol it follows is any communication protocol that can be applied to the technical solution of the present application, and is not specifically limited here; the input and output interface 25 is used to obtain external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs and is not specifically limited here.

[0060] In addition, the memory 22, as a carrier for storing resources, can be a read-only memory, a random access memory, a disk or an optical disk, etc. The resources stored thereon may include an operating system 221, a computer program 222 and data 223, etc. The storage method can be temporary storage or permanent storage. Among them, the operating system 221 is used to manage and control the hardware devices and computer programs 222 on the electronic device 20, so as to realize the operation and processing of the data 223 in the memory 22 by the processor 21, which can be Windows Server, Netware, Unix, Linux, etc. In addition to including a computer program that can be used to complete the weak power grid high adaptability control method of the train converter executed by the electronic device 20 disclosed in any of the aforementioned embodiments, the computer program 222 can further include a computer program that can be used to complete other specific tasks. In addition to including data transmitted from an external device received by the weak power grid high adaptability control device of the train converter, the data 223 can also include data collected by its own input and output interface 25, etc.

[0061] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0062] Furthermore, the present application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, the weak grid high adaptability control method of the train converter disclosed above is implemented. The specific steps of the method can refer to the corresponding contents disclosed in the above embodiments, and will not be repeated here.

[0063] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0064] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0065] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0066] If a flow chart is used in the present application, the flow chart is used to illustrate the operations performed by the system according to the embodiment of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, each step can be processed in reverse order or simultaneously. At the same time, other operations can also be added to these processes, or a certain step or several steps of operations can be removed from these processes.

[0067] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A highly adaptable control system for a weak power grid of a train converter, characterized in that: include: Sensors, traction converter circuits and control devices; The sensor is arranged in the traction converter circuit; The control device is connected to the traction converter circuit via the sensor; The sensor is used to measure the operating state of the traction converter circuit; The control device is used to obtain the operating status measured by the sensor and control the traction converter of the rail transit train.

2. The weak grid high adaptability control system of the train converter according to claim 1 is characterized in that: The traction converter circuit comprises: a pantograph, a circuit breaker, a traction transformer, a four-quadrant converter, a DC link, a traction inverter, a traction motor, a bidirectional chopper and an on-board energy storage; The circuit breaker is connected to the pantograph and the traction transformer respectively; The traction transformer is connected to the four-quadrant converter via a contactor; The four-quadrant converter is connected to the traction inverter via the DC link; The traction inverter is connected to the traction motor and the bidirectional chopper respectively; The bidirectional chopper is connected to the on-board energy storage.

3. The weak grid high adaptability control system of the train converter according to claim 2 is characterized in that: The sensors include: a grid-side voltage transformer, a grid-side current transformer, a four-quadrant current sensor and a DC voltage sensor; The grid-side voltage transformer is connected to the pantograph; The grid-side current transformer is connected to the circuit breaker and the traction transformer respectively; The four-quadrant current sensor is connected to the traction transformer and the four-quadrant converter respectively; The DC voltage sensor is connected to the four-quadrant converter and the traction inverter respectively.

4. The weak grid high adaptability control system of the train converter according to claim 1, characterized in that: The control device comprises: an operation status monitoring module, a grid-side reactive current extraction module, a reactive current tolerance calculation module, a reactive current instruction generation module, a dynamic reactive current compensation control module and a traction current conversion control module; The operation status monitoring module is respectively connected to the sensor, the grid-side reactive current extraction module, the reactive current tolerance calculation module and the reactive current instruction generation module; The grid-side reactive current extraction module is connected to the dynamic reactive current compensation control module; The reactive current tolerance calculation module is connected to the reactive current instruction generation module; The reactive current instruction generation module is connected to the dynamic reactive current compensation control module; The dynamic reactive current compensation control module is connected to the traction current conversion control module; The operation status monitoring module is used to obtain the grid voltage status signal, the grid side current signal and the train operation condition data through the sensor; The grid-side reactive current extraction module is used to calculate the reactive component of the grid-side current in real time according to the grid voltage state signal and the grid-side current signal; The reactive current tolerance calculation module is used to calculate the maximum reactive current tolerance of the current traction converter in real time according to the grid voltage state signal and the grid-side current signal; The reactive current instruction generation module is used to calculate the reactive current control reference signal for the grid voltage support function in real time according to the grid voltage state signal, the grid-side current signal and the maximum reactive current tolerance; The dynamic reactive current compensation control module is used to track the reactive current control reference signal in real time; The traction current conversion control module is used to compensate for the grid voltage, suppress grid-side current harmonics, stabilize the DC voltage, and control the traction motor.

5. A method for controlling a weak power grid with high adaptability of a train converter, based on the weak power grid with high adaptability control system of the train converter according to claims 1 to 4, characterized in that: The steps include: In the program initialization stage, write the rail transit train traction characteristic curve and the maximum reactive current tolerance value; Get the effective value of the grid voltage at the pantograph; Generate a reactive current instruction according to the rail transit train traction characteristic curve, the maximum reactive current tolerance value and the effective value of the grid voltage at the pantograph; The dynamic reactive power compensation real-time control strategy is executed through the reactive current instruction to control the operation of the train converter.

6. The method for controlling a weak power grid with high adaptability of a train converter according to claim 5, characterized in that: In the program initialization stage, the rail transit train traction characteristic curve and the maximum reactive current tolerance value are written, specifically including: During the program initialization phase, the rail transit train traction characteristic curve and the maximum reactive current tolerance value are written into the reactive current instruction generation module.

7. The method for controlling a weak power grid with high adaptability of a train converter according to claim 6, characterized in that: In the program initialization stage, the rail transit train traction characteristic curve is written, specifically including: The rail transit train traction characteristic curve is written to obtain compensation voltage threshold 1 and compensation voltage threshold 2.

8. The method for controlling a weak power grid with high adaptability of a train converter according to claim 7, characterized in that: The compensation voltage threshold 1 corresponds to the lower voltage limit value of the train output rated power range in the traction characteristic curve; the compensation threshold 2 corresponds to the lowest continuous voltage value in the traction characteristic curve.

9. The method for controlling a weak power grid with high adaptability of a train converter according to claim 7, characterized in that: The generating of the reactive current instruction according to the rail transit train traction characteristic curve, the maximum reactive current tolerance value and the effective value of the grid voltage at the pantograph specifically includes: A reactive current instruction is generated according to the compensation voltage threshold 1, the compensation voltage threshold 2 and the effective value of the grid voltage at the pantograph.

10. The method for controlling a weak power grid with high adaptability of a train converter according to claim 9, characterized in that: The generating of the reactive current instruction according to the compensation voltage threshold 1, the compensation voltage threshold 2 and the effective value of the grid voltage at the pantograph specifically includes: When the effective value of the grid voltage at the pantograph is greater than or equal to the compensation voltage threshold 1, there is no need to compensate the traction grid voltage, and at this time the reactive current command is 0; When the effective value of the grid voltage at the pantograph is less than the compensation voltage threshold 1 and greater than or equal to the compensation voltage threshold 2, the traction grid voltage needs to be compensated, and at this time, the reactive current instruction is between 0 and the maximum allowable reactive current corresponding to the compensation voltage threshold 2; When the effective value of the grid voltage at the pantograph is less than the compensation voltage threshold 2, the traction grid voltage needs to be compensated to the maximum extent, and at this time, the reactive current instruction is the maximum reactive current tolerance value.

11. The method for controlling a weak power grid with high adaptability of a train converter according to claim 5, characterized in that: The obtaining of the effective value of the grid voltage at the pantograph specifically includes: After the voltage signal collected by the grid voltage transformer is digitally filtered, the effective value of the grid voltage at the pantograph is calculated by a preset method.

12. The method for controlling a weak power grid with high adaptability of a train converter according to claim 5, characterized in that: The dynamic reactive power compensation real-time control strategy is generated in the following way: On the basis of the basic control strategy of the four-quadrant converter on the rail transit train network side, a reactive power compensation link is added to form the dynamic reactive power compensation real-time control strategy; Wherein, the instructions of the reactive power compensation link are generated by a reactive power instruction generation module.

13. The method for controlling a weak power grid with high adaptability of a train converter according to claim 5, characterized in that: The method of executing the dynamic reactive compensation real-time control strategy through the reactive current instruction to control the operation of the train converter specifically includes: The reactive power instruction generation module generates the grid-side reactive power compensation component reference value ; Set the DC voltage reference value Real-time value of DC voltage The grid-side active component reference value is obtained through the PI controller ; The grid-side reactive compensation component reference value and grid-side active component reference value The current components are compared with the grid-side reactive current component and the grid-side active current component, and a modulation reference wave is generated through the PI controller. ; The modulated reference wave Generate a switching pulse signal through a carrier modulation algorithm; The operation of the train converter is controlled according to the switch pulse signal.

14. An electronic device, characterized in that: include: at least one processor; as well as A memory communicatively connected to the at least one processor, the memory storing a computer program executable by the at least one processor, the computer program being executed by the at least one processor so that the at least one processor can execute the method of any one of claims 5 to 13.

15. A computer-readable storage medium, characterized in that: The storage medium is used to store a computer program, and the computer program is used to enable a computer to execute the method according to any one of claims 5 to 13.

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