Network construction type three-level converter control system and dynamic configuration method thereof

Abstract

The invention relates to a networking type three-level converter control system and a dynamic configuration method thereof, the networking type three-level converter control system comprises a redundant main control unit, a function unit, a six-phase power unit and a chopping unit, the redundant main control unit is connected with the function unit through an optical fiber, the function unit is respectively connected with the six-phase power unit and the chopping unit through optical fibers, and the chopping unit is connected with the six-phase power unit. The chopping unit is connected with the two ends of the direct current capacitor side of the inversion unit of the six-phase power unit; the main control unit and the pulse distribution unit are compact in sampling and modularized in design, small in occupied space, comprehensive in function, high in expandability and excellent in control performance, a dynamic configuration method is adopted, the redundant main control unit can be replaced on line, no power-on sequence requirement exists between the main control unit and each functional unit, and the power-on reliability is high. According to the invention, parameters of the pulse distribution unit can be forcibly updated on line, each functional module is independent, a more complex control system can be combined, and the system is convenient to use and maintain and is suitable for application occasions of complex control systems such as a network-forming converter and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power converters, and in particular to a grid-type three-level converter control system and a dynamic configuration method thereof. Background Art

[0002] As the penetration rate of new energy and power electronic equipment increases, the inertia of the power system decreases, and the stability problem becomes prominent. The grid-type converter technology comes into being to enhance the stability of the power system. It can not only improve the stability and regulation ability of the power system, but also provide voltage source support when the power grid is disturbed, and solve the problems of insufficient peak and frequency regulation capabilities and low voltage stability margin. With the continuous advancement of technology and the improvement of standards, the grid-type converter will play an increasingly important role in the power system with a high proportion of new energy as the main body.

[0003] The existing grid-type converter control system has a complex structure and large size. It is generally designed according to customized requirements, with single module functions and weak scalability. The control system parameter configuration adopts a static configuration method, and the parameter configuration is only performed once when the control system is powered on. The configuration parameters of each functional unit cannot be updated online dynamically. When any component of the system fails, the system must be shut down for maintenance. There are strict power-on sequence requirements between the main control unit and each functional unit, which is extremely inconvenient for system debugging and maintenance.

[0004] In summary, the research has realized a grid-type converter control system with compact control system architecture, excellent control performance, strong scalability, and easy maintenance, and its dynamic configuration method, which is of great significance to meet the requirements of the increasingly developed grid-type converter devices. Summary of the invention

[0005] The present invention provides a compact control system for a grid-type converter and a dynamic configuration method thereof, which includes a converter control system architecture and various functional units, and has the advantages of compact and modular structure, no power-on sequence requirements between functional units, online maintenance of functional units, and online updating of system configuration parameters.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A meshed three-level converter control system, comprising a redundant main control unit, a functional unit, a six-phase power unit and a chopper unit, wherein the redundant main control unit is connected to the functional unit via an optical fiber, the functional unit is respectively connected to the six-phase power unit and the chopper unit via an optical fiber, and the chopper unit is connected to both ends of a DC capacitor side of an inverter unit of the six-phase power unit;

[0008] The main control unit is used to perform the dynamic configuration process of the main node of the converter control system, and is responsible for the implementation of the converter control algorithm, and calculates the carrier frequency and the modulation wave for carrier comparison, and the generated carrier comparison value is sent to the pulse distribution unit;

[0009] The functional unit is used to perform the converter control system slave node dynamic configuration process, to receive the carrier comparison value calculated by the main control unit, and to generate the IGBT drive signal required by the six-phase power unit;

[0010] The six-phase power unit is used for rectification and inversion of the converter;

[0011] The chopper unit is used for overvoltage protection of the six-phase power unit.

[0012] Furthermore, the main control unit integrates a DSP operation unit, an FPGA execution unit, a CAN / 485 communication module, and a high-speed optical port communication module. The main control unit is powered by a 24V isolated dual power supply. The redundant main control units communicate with each other through their respective high-speed optical port communication modules, and DI / DO modules and display units are arranged between the redundant main control units, and the DI / DO modules and display units are connected to the CAN / 485 communication module.

[0013] Furthermore, the functional unit includes a pulse distribution unit, a recording unit, a TCP / UDP communication module and an analog quantity acquisition unit. The signal output end of the pulse distribution unit is connected to the six-phase power unit and the chopping unit, the TCP / UDP communication module of the functional unit is connected to the communication port of the main control unit, the signal input end of the analog quantity acquisition unit is connected to the CT / PT conversion module, and the output ends of the pulse distribution unit, the recording unit and the analog quantity acquisition unit are connected to the communication port of the main control unit.

[0014] Furthermore, the power unit includes a three-phase power unit on the rectifier side and a three-phase power unit on the inverter side. The signal input end of the three-phase power unit on the rectifier side is connected to the transformer, and the signal output end is connected to the inverter unit of the three-phase power unit on the inverter side to supply power to the power part. The signal output end of the three-phase power unit on the inverter side is connected to the motor load, and each power unit is connected by a copper busbar.

[0015] Furthermore, the high-speed optical port communication module has a high-speed optical fiber serdes interface.

[0016] A dynamic configuration method for a grid-type three-level converter control system comprises the following steps:

[0017] S1. Dynamic configuration communication mode: Full-duplex communication is performed between the main board unit and the functional unit through a high-speed optical port communication module, supporting pure communication mode and configuration mode of the functional board. The configuration mode includes dynamic configuration and reconfiguration mode. The two modes are configured and set by the main control unit, and a question-and-answer communication method is adopted; when the main control unit is configured in pure communication mode, control data interaction is completed in each cycle; when the main control unit is configured in functional unit configuration mode, dynamic configuration of the functional unit is performed, and only configuration command frames are sent before the functional unit configuration is passed. After the configuration is passed, the functional unit receives a control data frame and then feeds back a control command frame, and receives a configuration data frame and then feeds back a configuration data frame;

[0018] S2. Dynamic configuration of the master node of the main control unit: the main control unit is configured and enters the control cycle communication, and determines the configured communication mode. If it is configured as a pure communication mode, it enters the control cycle and starts the control cycle data interaction; if it is configured as a functional unit configuration mode, the master node first sends a configuration data frame, and the functional unit feeds back the configuration data frame. The master node parses the data frame fed back by the functional board, and compares the fed-back configuration parameters with the configuration parameters issued by the main control unit one by one. If all configuration data contents are consistent, it enters the control cycle data interaction and starts sending data frames containing configuration authentication, otherwise it records the serial numbers of inconsistent parameters and feedback parameters. If the main control unit receives three consecutive frames of configuration feedback data frames from the functional unit, it returns to the master node to send the configuration data frame process again, and re-executes the S2 process until the master node receives the control data frame and enters the control cycle data interaction;

[0019] S3. Dynamic configuration of slave nodes of functional units: When the functional unit is powered on, it is in the configuration cycle by default for data interaction, and only the configuration data frame is fed back. If the optical fiber communication from the main control unit to the functional unit is interrupted, the configuration data frame is fed back periodically; if the control data frame of the main control unit is received, and the configuration data frame has been received, and the configuration data is compared and correct, then the control cycle is entered, and the configuration data frame is fed back when the configuration data frame is received, and the control data frame is fed back when the control command frame is received. At this time, if the optical fiber communication from the main control unit to the functional unit is interrupted, the control data frame is fed back periodically; finally, if a reconfiguration command issued by the main control unit is received, the slave node dynamic configuration process is re-entered and the S3 process is re-executed;

[0020] S4. Dynamically configured configuration arbitration process: After the functional unit receives the configuration data frame from the node and completes the local configuration, it starts the configuration data frame feedback. The control data frame feedback has two time points, one is the configuration time, and the other is the automatic timing of the slave node according to the set time point to delay the feedback;

[0021] S5. Dynamic configuration reconfiguration process: The configuration instruction master control unit ensures that all functional units are forcibly reconfigured at any time to ensure that the configuration parameters of the functional units can be updated online.

[0022] Furthermore, the dynamic configuration of the master node of the main control unit is initiated by the master node, and the redundant main control units dynamically configure the functional units at the same time without conflict. By setting which of the redundant main control units is the master and which is the slave, the functional unit decides whose data to receive.

[0023] Furthermore, the slave nodes of the functional units are dynamically configured, and after the pulse distribution unit is powered on, the master control unit that first sends the configuration data frame is configured. If the configuration is successful, the configuration parameters are latched, and the feedback configuration data frames received by the redundant master control unit high-speed optical port communication modules all use the latched configuration parameters on a first-come, first-served basis.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The core main control unit and pulse distribution unit of the control system adopt a compact and modular design, occupying a small space, and having comprehensive functions and excellent control performance. Compared with the traditional static configuration method, the dynamic configuration method has the advantage that the redundant boards of the main control unit can be replaced online, and there is no power-on sequence requirement between the main control unit and each functional unit, and the configuration parameters of the functional unit can be forced to be updated online; in this compact control system of the present invention, each functional module is relatively independent and can be combined into a more complex control system. It is very convenient to use and maintain, and is very suitable for application scenarios of complex control systems such as networking. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the grid-type converter control system described in the present invention.

[0027] Figure 2 It is a connection diagram of the main control unit and the functional unit of the present invention.

[0028] Figure 3 It is a schematic diagram of the dynamic configuration data exchange method described in the present invention.

[0029] Figure 4 It is a flowchart for implementing the dynamic configuration of slave nodes of the functional unit described in the present invention.

[0030] Figure 5 This is a schematic diagram of the dynamic configuration data exchange method of the present invention. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0032] See Figure 1 , is a structural schematic diagram of the control system of the present invention. A meshed three-level converter control system of the present invention includes a control layer and a power layer, the control layer includes a redundant main control unit and a functional unit, the power layer includes a three-phase power unit A, B, C on the rectifier side of a six-phase power unit, a three-phase power unit U, V, W on the inverter side and a chopper unit, the redundant main control unit is connected to the functional unit through an optical fiber, the functional unit is respectively connected to the six-phase power unit and the chopper unit through an optical fiber, and the chopper unit is connected to both ends of the DC capacitor side of the inverter unit of the six-phase power unit.

[0033] See Figure 2 The main control unit and each functional unit adopt a compact modular design. The main control unit integrates a DSP operation unit and an FPGA execution unit, and integrates a CAN / 485 communication module and a high-speed optical port communication module. The main control unit is powered by a 24V isolated dual power supply. The redundant main control units communicate through their respective high-speed optical port communication modules, and DI / DO modules and display units are arranged between the redundant main control units. The DI / DO modules and display units are connected to the CAN / 485 communication module; the main control unit is responsible for the implementation of the dynamic configuration process of the main node of the converter control system, and is also responsible for the implementation of the converter control algorithm, and calculates the carrier frequency and the modulation wave for carrier comparison, and generates a carrier comparison value to send to the pulse distribution unit.

[0034] The functional unit includes a pulse distribution unit, a wave recording unit, a TCP / UDP communication module and an analog quantity acquisition unit. The signal output end of the pulse distribution unit is connected to the six-phase power unit and the chopper unit. The TCP / UDP communication module of the functional unit is connected to the communication port of the high-speed optical port communication module of the main control unit. The signal input end of the analog quantity acquisition unit is connected to the CT / PT conversion module. The output ends of the pulse distribution unit, the wave recording unit and the analog quantity acquisition unit are connected to the communication port of the high-speed optical port communication module of the main control unit.

[0035] The pulse distribution unit is used to realize the modulation of the rectification and inversion signals of the power unit, and is responsible for the realization of the dynamic configuration process of the converter control system slave node. It is also used to receive the carrier comparison value calculated by the main control unit, adopts a three-level modulation method, and generates the IGBT drive signal required by the six-phase power unit by adding a dead zone and a minimum pulse width through a state machine;

[0036] The analog quantity acquisition unit is responsible for collecting external signals of the converter control system. The output voltage and output current signals are converted by the CT / PT module and sent to the analog quantity acquisition unit for system control and protection.

[0037] The recording unit is responsible for recording the data of the converter control system. It can record the modulation wave, output voltage, output current and other data of the system operation in real time. It also has transient recording and steady-state recording functions. When a fault occurs in any part of the system, it can record the data content at the time of the fault.

[0038] The power unit includes a three-phase power unit on the rectifier side and a three-phase power unit on the inverter side. The signal input end of the three-phase power unit on the rectifier side is connected to the transformer, and the signal output end is connected to the inverter unit of the three-phase power unit on the inverter side to supply power to the power part. The signal output end of the three-phase power unit on the inverter side is connected to the motor load, and each power unit is connected through a copper bus. The chopper unit is connected to the two ends of the DC capacitor side of the inverter unit. When it is determined that the DC capacitor voltage of the power unit is higher than the limit value, the chopper unit starts the chopping step-down function to ensure that the output voltage is within a reasonable range and play an overvoltage protection role.

[0039] The three-phase power unit on the inverter side is responsible for realizing the three-level inverter output, and the signal output terminal is connected to the motor load. The three-phase power unit on the rectifier side is responsible for rectification and provides power for the entire converter power part. The chopper unit is used for overvoltage protection of the power unit. When the DC power supply is higher than the set value, the chopper unit is started to achieve the purpose of step-down protection device.

[0040] A dynamic configuration method for a grid-type three-level converter control system comprises the following steps:

[0041] S1. Dynamic configuration of communication and data interaction methods: see Figure 3 The main board unit and the functional unit achieve full-duplex communication through a high-speed optical fiber serdes interface, supporting pure communication mode and configuration mode of the functional board. The configuration mode includes dynamic configuration and reconfiguration mode. The two modes are configured and set by the main control unit, and a question-and-answer communication method is adopted. When the main control unit is configured in pure communication mode, control data interaction is completed in each cycle. When the main control unit is configured in functional board configuration mode, the module needs to perform dynamic configuration of the functional board. Before the functional board configuration is passed, only the configuration command frame is sent. After the configuration is passed, the functional board receives a control data frame and then feeds back a control command frame. After receiving a configuration data frame, it feeds back a configuration data frame.

[0042] S2. Implementation process of dynamic configuration of the master node of the master control unit: see Figure 4, the main control unit is configured and enters the control cycle communication, and the configured communication mode is determined. If it is configured as a pure communication mode, it enters the control cycle and starts the control cycle data interaction; if it is configured as a functional unit configuration mode, the master node first sends a configuration data frame, and at the same time, the functional board of the functional unit feeds back a configuration data frame. The master node parses the data frame fed back by the functional board, and compares the fed-back configuration parameters with the configuration parameters issued by the main control unit one by one. If all configuration data contents are consistent, it enters the control cycle data interaction and starts sending data frames containing configuration authentication. Otherwise, the serial number and feedback parameters of the inconsistent parameters are recorded for analysis by the main control unit. If the main control unit receives three consecutive frames of configuration feedback data frames from the functional unit, it returns to the main node to send the configuration data frame process again, and re-executes the S2 process until the main node receives the control data frame and enters the control cycle data interaction; the redundant main control unit is the main node for dynamic configuration, and the dynamic configuration is also initiated by the main node. The two dynamically configure the functional boards of each main control unit at the same time, and there is no conflict. By setting who is the master and who is the slave, the functional board of the main control unit decides whose data to receive.

[0043] S3. Implementation process of dynamic configuration of slave nodes of functional units: see Figure 5 First, when the functional unit is powered on, it is in the configuration cycle by default for data interaction, and only the configuration data frame is fed back. If the optical fiber communication from the main control unit to the functional unit is interrupted, the configuration data frame is fed back periodically. Then, if the control data frame from the main control unit is received, and the configuration data frame has been received, and the configuration data is compared and correct, it enters the control cycle. When the configuration data frame is received, the configuration data frame is fed back. When the control command frame is received, the control data frame is fed back. At this time, if the optical fiber communication from the main control unit to the functional unit is interrupted, the control data frame is fed back periodically. Finally, if the reconfiguration command issued by the main control unit is received, the slave node dynamic configuration process is re-entered and the S3 process is re-executed. If the pulse distribution unit has two optical ports connected to two main control units respectively, the main control unit that sends the configuration data frame first after the pulse distribution unit is powered on is configured. If the configuration is passed, the configuration parameters are latched. The configuration data frames fed back by the two optical ports all use the latched configuration parameters, and a first-come, first-served method is adopted.

[0044] S4. Configuration arbitration process of dynamic configuration: Since the main control unit is dual-set redundant, one set must be selected for configuration of the functional unit and the parameters must be locked. Unless there is a clear parameter change command, the locked parameters are not allowed to be modified to avoid confusion. One of the redundant main control units is defined as main control unit A, and the other is defined as main control unit B. The functional unit communicates with the main control unit A through the TCP / UDP communication module, and communicates with the main control unit B through another TCP / UDP communication module. When the functional unit is powered on, the high-speed optical port communication module of the main control unit A will be enabled to receive first, and the high-speed optical port communication module of the main control unit B will be enabled to receive after a delay of 1S; in this way, it is ensured that: when the functional unit is powered on at night in the two sets of main control units, all functional units are configured by the corresponding main control unit A as much as possible.

[0045] S5. Dynamic configuration reconfiguration process: Since the configuration parameters of the functional unit are locked once, if the functional unit needs to be powered on again, the main control unit can force reconfiguration of all functional units at any time through reconfiguration instructions to realize online update of the configuration parameters of the functional units. This is a function set up to facilitate parameter modification.

[0046] The above embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the above embodiments. The methods used in the above embodiments are conventional methods unless otherwise specified.

Claims

1. A grid-type three-level converter control system, characterized in that: It includes a redundant main control unit, a functional unit, a six-phase power unit and a chopper unit, wherein the redundant main control unit is connected to the functional unit via an optical fiber, the functional unit is respectively connected to the six-phase power unit and the chopper unit via optical fibers, and the chopper unit is connected to both ends of the DC capacitor side of the inverter unit of the six-phase power unit; The main control unit is used to perform the dynamic configuration process of the main node of the converter control system, and is responsible for the implementation of the converter control algorithm, and calculates the carrier frequency and the modulation wave for carrier comparison, and the generated carrier comparison value is sent to the pulse distribution unit; The functional unit is used to perform the converter control system slave node dynamic configuration process, to receive the carrier comparison value calculated by the main control unit, and to generate the IGBT drive signal required by the six-phase power unit; The six-phase power unit is used for rectification and inversion of the converter; The chopper unit is used for overvoltage protection of the six-phase power unit.

2. A grid-type three-level converter control system according to claim 1, characterized in that: The main control unit integrates a DSP operation unit, an FPGA execution unit, a CAN / 485 communication module, and a high-speed optical port communication module. The main control unit is powered by a 24V isolated dual power supply. The redundant main control units communicate with each other through their respective high-speed optical port communication modules, and DI / DO modules and display units are arranged between the redundant main control units, and the DI / DO modules and display units are connected to the CAN / 485 communication module.

3. A grid-type three-level converter control system according to claim 1, characterized in that: The functional unit includes a pulse distribution unit, a recording unit, a TCP / UDP communication module and an analog quantity acquisition unit. The signal output end of the pulse distribution unit is connected to the six-phase power unit and the chopper unit. The TCP / UDP communication module of the functional unit is connected to the communication port of the main control unit. The signal input end of the analog quantity acquisition unit is connected to the CT / PT conversion module. The output ends of the pulse distribution unit, the recording unit and the analog quantity acquisition unit are connected to the communication port of the main control unit.

4. A grid-type three-level converter control system according to claim 1, characterized in that: The power unit includes a three-phase power unit on the rectifier side and a three-phase power unit on the inverter side. The signal input end of the three-phase power unit on the rectifier side is connected to the transformer, and the signal output end is connected to the inverter unit of the three-phase power unit on the inverter side to supply power to the power part. The signal output end of the three-phase power unit on the inverter side is connected to the motor load, and each power unit is connected by a copper busbar.

5. A grid-type three-level converter control system according to claim 1, characterized in that: The high-speed optical port communication module is provided with a high-speed optical fiber serdes interface.

6. A dynamic configuration method for a grid-type three-level converter control system according to any one of claims 1 to 5, characterized in that: The steps include: S1. Dynamic configuration communication and data interaction mode: Full-duplex communication is performed between the main board unit and the functional unit through a high-speed optical port communication module, supporting pure communication mode and configuration mode of the functional board. The configuration mode includes dynamic configuration and reconfiguration mode. The two modes are configured and set by the main control unit, and a question-and-answer communication method is adopted; when the main control unit is configured in pure communication mode, control data interaction is completed in each cycle; when the main control unit is configured in functional unit configuration mode, dynamic configuration of the functional unit is performed, and only configuration command frames are sent before the functional unit configuration is passed. After the configuration is passed, the functional unit receives a control data frame and then feeds back a control command frame, and receives a configuration data frame and then feeds back a configuration data frame; S2. Dynamic configuration of the master node of the main control unit: the main control unit is configured and enters the control cycle communication, and determines the configured communication mode. If it is configured as a pure communication mode, it enters the control cycle and starts the control cycle data interaction; if it is configured as a functional unit configuration mode, the master node first sends a configuration data frame, and the functional unit feeds back the configuration data frame. The master node parses the data frame fed back by the functional board, and compares the fed-back configuration parameters with the configuration parameters issued by the main control unit one by one. If all configuration data contents are consistent, it enters the control cycle data interaction and starts sending data frames containing configuration authentication. Otherwise, the serial numbers of inconsistent parameters and feedback parameters are recorded. If the main control unit receives three consecutive frames of configuration feedback data frames from the functional unit, it returns to the master node to send the configuration data frame process again, and re-executes the S2 process until the master node receives the control data frame and enters the control cycle data interaction; S3. Dynamic configuration of slave nodes of functional units: When the functional unit is powered on, it is in the configuration cycle by default for data interaction, and only the configuration data frame is fed back. If the optical fiber communication from the master control unit to the functional unit is interrupted, the configuration data frame is fed back periodically; If the control data frame of the main control unit is received, and the configuration data frame has been received, and the configuration data is compared and found to be correct, then the control cycle is entered, and the configuration data frame is fed back when the configuration data frame is received, and the control data frame is fed back when the control command frame is received. At this time, if the optical fiber communication from the main control unit to the functional unit is interrupted, the control data frame is fed back periodically; finally, if the reconfiguration command issued by the main control unit is received, the slave node dynamic configuration process is re-entered and the S3 process is re-executed; S4. Dynamically configured configuration arbitration process: After the functional unit receives the configuration data frame from the node and completes the local configuration, it starts the configuration data frame feedback. The control data frame feedback has two time points, one is the configuration time, and the other is the automatic timing of the slave node according to the set time point to delay the feedback; S5. Dynamic configuration reconfiguration process: The configuration instruction master control unit ensures that all functional units are forcibly reconfigured at any time to ensure that the configuration parameters of the functional units can be updated online.

7. A dynamic configuration method for a grid-type three-level converter control system according to claim 6, characterized in that: The dynamic configuration of the master node of the master control unit is initiated by the master node. The redundant master control units dynamically configure the functional units at the same time without conflict. The redundant master control units are set to be the master and the slave, and the functional units decide whose data to receive.

8. A dynamic configuration method for a grid-type three-level converter control system according to claim 6, characterized in that: The slave nodes of the functional units are dynamically configured. After the pulse distribution unit is powered on, the master control unit that first sends the configuration data frame is configured. If the configuration is successful, the configuration parameters are latched. The feedback configuration data frames received by the redundant master control unit high-speed optical port communication module all use the latched configuration parameters in a first-come, first-served manner.

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