SVG-based H-bridge bypass control method
The H-bridge bypass control method for SVG devices addresses instability by employing a system controller with dual drive circuits and self-testing to ensure reliable bypass operations, enhancing stability and reducing shutdown risks.
Patent Information
- Application Number
- CN202410617194.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2024-12-27
AI Technical Summary
Existing SVG devices face instability due to failed power module bypasses when control circuits are abnormal or communication is interrupted, leading to potential device shutdowns.
An H-bridge bypass control method utilizing a system controller to manage a bypass switch module with dual drive circuits and optical fiber communication, enabling self-testing and backup control mechanisms to ensure reliable bypass operations even in abnormal conditions.
Enhances the stability and reliability of SVG devices by ensuring successful bypasses even in abnormal conditions, reducing the risk of shutdowns and improving overall system operation.
Smart Images
Figure CN119209581A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of SVG control, and in particular to an H-bridge bypass control method based on SVG. Background Art
[0002] As the core device of advanced flexible AC technology, SVG device (Static Var Generator) has been widely used in power systems, metallurgy and steel rolling and other industrial sites. Due to the structure of the chain H bridge of SVG device, adding a bypass switch to the power module H bridge can effectively reduce the risk of SVG device failure and shutdown. When a power module fails during the operation of SVG device, the bypass switch bypasses the failed power module, and the SVG device can continue to operate normally and wait for later maintenance.
[0003] In the prior art, the patent announcement number is CN218183022U, and the patent name is "A H-bridge cascaded SVG power unit bypass control system". The upgrade measure of adding a bypass switch brings new problems: when the control circuit in the power module H-bridge is abnormal, or the optical fiber communication is interrupted, this module cannot normally receive the bypass switch action command or cannot give the correct bypass switch command, and cannot achieve successful bypass, affecting the stability of the SVG device. Summary of the invention
[0004] The object of the present invention is to provide an H-bridge bypass control method based on SVG, which can successfully implement bypass when the H-bridge of a power module is abnormal or the communication is interrupted, thereby improving the stability of the SVG device.
[0005] To achieve the above object, the present invention is implemented through the following technical solutions:
[0006] An H-bridge bypass control method based on SVG is based on system controller control. The method comprises an H-bridge control module, a bypass switch module, a bypass switch and an H-bridge cascade to form a power unit. The AC output side of each power unit formed by the H-bridge cascade is connected in parallel with the corresponding bypass switch. The H-bridge control module is used to receive instruction information from the system controller to drive the IGBT of the power unit formed by the corresponding H-bridge cascade to turn on / off. The H-bridge control module is also used to receive bypass instruction information from the system controller and transmit it to the corresponding bypass switch module. The bypass switch module is respectively connected to the H-bridge control module and the system controller through communication ports. The bypass switch module is used to drive the corresponding bypass switch to turn on / off.
[0007] The specific contents include the following:
[0008] 1) Self-test
[0009] When the SVG device is fully charged, in the locked pulse state, the system controller receives the current bypass switch state transmitted by the H-bridge control module and the bypass switch module, and performs a self-check: if the self-check fails, the SVG device trips, and if there is an alarm, the corresponding power unit is locked;
[0010] 2) SVG device unlocks the pulse and starts running
[0011] If there is an H-bridge control module upload failure, or an H-bridge control module communicates abnormally with the system controller, the content is as follows:
[0012] a. The system controller sends a bypass instruction to the H-bridge control module corresponding to the faulty power unit and starts timing;
[0013] b. If the set time Time1 is not exceeded and the system controller receives the bypass switch closing signal, the bypass is successful;
[0014] c. If no bypass success information is returned after the set time Time1, the system controller sends a bypass instruction to the bypass switch module corresponding to the faulty power unit and starts timing;
[0015] d. If the set time Time2 is not exceeded and the system controller receives the bypass switch closing signal, the bypass is successful;
[0016] e. If the bypass success message is not returned after the set time Time2, the SVG device will trip;
[0017] The set time Time1 is: the H-bridge control module receiving communication time + the bypass switch module receiving communication time + the bypass switch action time + the bypass switch module return communication time + the H-bridge control module return communication time + the margin time;
[0018] The set time Time2 is: bypass switch module receiving communication time + bypass switch action time + bypass switch module return communication time + margin time.
[0019] The H-bridge control module includes an IGBT drive circuit for driving the IGBT of the corresponding power unit. The bypass switch module is connected to the H-bridge control module and the system controller through optical fiber communication ports respectively. The H-bridge control module is connected to the system controller through optical fiber communication ports.
[0020] The system controller is provided with an optical fiber interface for transmitting control information.
[0021] The bypass switch module includes two sets of drive circuits, which are backup for each other and are used to drive corresponding bypass switches.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] 1. The system controller can directly control the bypass switch module to bypass, and it can serve as a backup for the bypass controlled by the H-bridge control module, thus improving the reliability of the H-bridge bypass;
[0024] 2. Each bypass switch module is equipped with two sets of drive circuits that serve as backup for each other to drive the bypass switch, thus improving the reliability of the bypass;
[0025] 3. After the SVG device is charged, it can perform self-checking in the locked pulse state. The bypass switch state given by the H-bridge control module and the bypass switch state given by the bypass switch module are referenced to each other. If the uploaded bypass state is inconsistent, an alarm will be issued in time and the bypass function of the power unit will be turned off, thereby improving the operating stability of the SVG device. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 This is the topology diagram of adding a bypass switch to the SVG device.
[0027] Figure 2 It is a topology diagram of a single power unit based on the H-bridge bypass control method of SVG.
[0028] Figure 3 The present invention is a flow chart of H-bridge bypass logic judgment of an H-bridge bypass control method based on SVG. DETAILED DESCRIPTION
[0029] The present invention is described in detail below in conjunction with the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.
[0030] The following examples are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.
[0031] [Example 1]
[0032] Based on the system controller control, the system controller has a fiber optic interface for transmitting communication information. Figure 1 ,See Figure 2, an H-bridge bypass control method based on SVG, comprising an H-bridge control module, a bypass switch module, a bypass switch K, and an H-bridge cascade to form a power unit, wherein the AC output side of each power unit formed by the H-bridge cascade is connected in parallel with the corresponding bypass switch K; the H-bridge control module is used to receive instruction information from a system controller to drive the IGBT of the power unit formed by the corresponding H-bridge cascade, and the H-bridge control module is also used to receive bypass instruction information from the system controller and transmit it to the corresponding bypass switch module; the bypass switch module communicates with both the H-bridge control module and the system controller, receives the bypass instruction and drives the corresponding bypass switch K to conduct. The bypass switch module has an independent energy-taking power supply circuit for supplying power to the bypass switch module. The H-bridge control module also has an independent energy-taking power supply circuit for supplying power to the H-bridge control module. The energy-taking power supply circuit of the bypass switch module and the energy-taking power supply circuit of the H-bridge control module are both independently set, and no matter what abnormality occurs in the H-bridge control module, the energy-taking of the bypass switch module is not affected by it. The H-bridge control module includes a DC voltage sampling, an energy-taking power supply circuit, an IGBT drive circuit, and an external communication interface circuit, and is used to receive trigger pulse signals and bypass commands issued by the system controller.
[0033] An H-bridge bypass control method based on SVG is as follows:
[0034] 1. Normal H-bridge bypass process
[0035] ①The system controller sends a bypass command to the faulty H-bridge control module;
[0036] ② The faulty H-bridge control module receives the bypass command and sends it to the bypass switch module;
[0037] ③ After receiving the bypass command from the H-bridge control module, the bypass switch module controls the bypass switch K to close, completing the faulty H-bridge bypass function.
[0038] 2. Abnormal H-bridge bypass process
[0039] ①The system controller sends a bypass command to the faulty H-bridge control module;
[0040] ② The faulty H-bridge control module is out of control or the communication is disconnected, and the bypass command is not sent to the bypass switch module; or the communication interface or execution circuit between the bypass switch module and the H-bridge control module is abnormal, and the bypass is not executed;
[0041] ③ When the set time Time1 is exceeded, the system controller sends a bypass command to the bypass switch module corresponding to the faulty H bridge;
[0042] ④ The communication interface and execution circuit between the bypass switch module and the system controller are normal, and the H-bridge is successfully bypassed.
[0043] 3. If the two independent energy storage power circuits and communication ports in the bypass switch module are abnormal, the SVG bypass fails and trips.
[0044] See Figure 3 , the H-bridge bypass control process based on SVG is as follows:
[0045] S1. After the SVG device is charged, it performs a bypass function self-test, see Table 1;
[0046] Table 1 is the bypass self-test logic table
[0047]
[0048] S2: If the self-test fails, the circuit breaker will be tripped; if there is an alarm, the bypass function of the corresponding H-bridge module will be locked; after the self-test is completed, the circuit breaker will enter the S3 step and wait for the bypass function to be triggered;
[0049] S3, the system controller of the SVG device receives an H-bridge fault signal uploaded by the H-bridge control module, or the optical fiber communication between the system controller of the SVG device and the H-bridge control module is disconnected, or the system controller of the SVG device receives a manual command to bypass a power module, triggering the bypass logic judgment;
[0050] S4, determine whether the H-bridge module that currently needs to be bypassed is in the bypass locked state, if so, turn to trip; otherwise, turn to step S5;
[0051] S5, judging whether the bypass quantity in the phase where the H-bridge module currently needs to be bypassed exceeds the set bypass upper limit, if it exceeds the limit, it turns to tripping; otherwise, it turns to S6 step;
[0052] S6, the system controller sends a bypass command to the H-bridge control module that currently needs to be bypassed, and starts timing;
[0053] S7. If the system controller receives the bypass switch K closing signal before the set time Time1 is exceeded, the bypass is successful; otherwise, the system controller sends a bypass command to the bypass switch module corresponding to the H bridge that currently needs to be bypassed, and starts timing again;
[0054] S8. If the system controller receives the bypass switch K closing signal before the set time Time2 is exceeded, the bypass is successful; otherwise, the bypass fails and turns to tripping.
[0055] S9: After bypass is successful, go to step S3 and continue to wait for the bypass logic to be triggered.
[0056] Among them, the set time Time1 is:
[0057] H-bridge control module receiving communication time + bypass switch module receiving communication time + bypass switch K action time + bypass switch module return communication time + H-bridge control module return communication time + margin time;
[0058] Set the time Time2 to:
[0059] Bypass switch module receiving communication time + bypass switch K action time + bypass switch module return communication time + margin time.
[0060] The system controller of the present invention can directly control the bypass switch module to bypass, and the bypass control module and the H-bridge control module are mutually backed up, thereby improving the reliability of the H-bridge bypass; two sets of drive circuits that are mutually backed up are arranged inside each bypass switch module to drive the bypass switch, thereby improving the reliability of the bypass; after the SVG device is charged, it can perform self-checking in the locked pulse state, and the bypass switch state given by the H-bridge control module and the bypass switch state given by the bypass switch module are mutually referenced. When the uploaded bypass states are inconsistent, an alarm is given in time and the bypass function of the power unit is turned off, thereby improving the operation stability of the SVG device.
Claims
1. An H-bridge bypass control method based on SVG, based on system controller control, characterized in that: The power unit is composed of an H-bridge control module, a bypass switch module, a bypass switch, and an H-bridge cascade. The AC output side of each power unit composed of the H-bridge cascade is connected in parallel with the corresponding bypass switch. The H-bridge control module is used to receive instruction information from the system controller to drive the IGBT of the power unit composed of the corresponding H-bridge cascade to turn on / off. The H-bridge control module is also used to receive bypass instruction information from the system controller and transmit it to the corresponding bypass switch module. The bypass switch module is respectively connected to the H-bridge control module and the system controller through communication ports, and the bypass switch module is used to drive the corresponding bypass switch to turn on / off.
2. The H-bridge bypass control method based on SVG according to claim 1, characterized in that: The specific contents include the following: 1) Self-test When the SVG device is fully charged, in the locked pulse state, the system controller receives the current bypass switch state transmitted by the H-bridge control module and the bypass switch module, and performs a self-check: if the self-check fails, the SVG device trips, and if there is an alarm, the corresponding power unit is locked; 2) SVG device unlocks the pulse and starts running If there is an H-bridge control module upload failure, or an H-bridge control module communicates abnormally with the system controller, the content is as follows: a. The system controller sends a bypass instruction to the H-bridge control module corresponding to the faulty power unit and starts timing; b. If the set time Time1 is not exceeded and the system controller receives the bypass switch closing signal, the bypass is successful; c. If no bypass success information is returned after the set time Time1, the system controller sends a bypass instruction to the bypass switch module corresponding to the faulty power unit and starts timing; d. If the set time Time2 is not exceeded and the system controller receives the bypass switch closing signal, the bypass is successful; e. If the bypass success message is not returned after the set time Time2, the SVG device will trip; The set time Time1 is: the H-bridge control module receiving communication time + the bypass switch module receiving communication time + the bypass switch action time + the bypass switch module return communication time + the H-bridge control module return communication time + the margin time; The set time Time2 is: bypass switch module receiving communication time + bypass switch action time + bypass switch module return communication time + margin time.
3. The H-bridge bypass control method based on SVG according to claim 2, characterized in that: The H-bridge control module includes an IGBT drive circuit for driving the IGBT of the corresponding power unit. The bypass switch module is connected to the H-bridge control module and the system controller through optical fiber communication ports respectively. The H-bridge control module is connected to the system controller through optical fiber communication ports.
4. The H-bridge bypass control method based on SVG according to claim 3, characterized in that: The system controller is provided with an optical fiber interface for transmitting control information.
5. The H-bridge bypass control method based on SVG according to claim 1, characterized in that: The bypass switch module includes two sets of drive circuits, which are standby for each other and are used to drive corresponding bypass switches.