An online weight switching control method for a high-redundancy excitation system

Abstract

This disclosure relates to the field of excitation control technology, and particularly to an online control method for switching control of a high-redundancy excitation system. The excitation regulating cabinet has two control channels and multiple intelligent power cabinets with configured controllers, all interconnected via optical fiber. This disclosure sets the control channels as high priority and the intelligent power cabinets as low priority, and introduces a sub-priority and communication status monitoring mechanism. The strategy stipulates that the power cabinet can only participate in control contention when all communication between the control channels and the power cabinets fails; the allocation of control is determined based on the number of controllers with normal communication and the sub-priority delay; when a low-priority controller is online, a high-priority controller can only automatically take over control under static conditions. This strategy effectively solves the coordination control problem of distributed multi-controller systems, significantly improving the operational reliability, safety, and redundancy of the excitation system.

Description

Technical Field

[0001] This disclosure relates to the field of excitation control technology, and in particular to an online weight switching control method for a high-redundancy excitation system. Background Technology

[0002] Because the output current of a single thyristor is limited, and considering output redundancy, excitation systems typically employ multiple parallel-connected thyristor rectifier bridges. The electrical cabinet in the excitation system equipped with thyristor rectifier bridges is called a power cabinet. In a classic dual-channel excitation system, the control channel generates trigger pulses, which are then output in parallel to each power cabinet. To ensure consistent output current across all power cabinets, intelligent current sharing schemes have emerged. These schemes equip the power cabinets with controllers, and the excitation regulating cabinet's control channel sends the trigger angle to the power cabinets via communication, allowing each power cabinet to generate its own trigger pulse. This allows the power cabinet to fine-tune its trigger angle based on its own output current, ensuring consistent output current. In intelligent current sharing schemes, power cabinets equipped with controllers are called intelligent power cabinets.

[0003] Existing technology, based on intelligent current sharing solutions, enables communication and interconnection between power cabinets, and also equips the power cabinets with excitation control functions. In addition to two high-priority control channels and a low-priority intelligent power cabinet, the excitation controller also has a second-highest priority demagnetizing cabinet controller, which can perform excitation control in a constant excitation current mode. The interaction information between the controllers includes control angles and status information; the received controller status information determines whether its status is normal. When the power cabinet is self-excited, it operates in constant anode voltage mode. If a high-priority controller recovers normal operation while a low-priority controller is in online control, the online control will not automatically switch to the high-priority controller.

[0004] Figure 1 and Figure 2 This is the transfer function of the PID control for the excitation system, where V is the measured value and Ref is the setpoint. For the excitation regulating cabinet control channel, when the generator terminal voltage is the controlled object, V is the generator terminal voltage; when the generator excitation current is the controlled object, V is the excitation current. Figure 1 In the transfer function of a parallel PID controller, K P It is the magnification factor, K. I It is the integral coefficient, K D These are the differential coefficients. The implementation method in the program is as follows: (1) (2) (3) (4) (5) (6) Where, ΔV k+1 It is the deviation between the current measured value and the given value, ΔV k It is the deviation between the measured value and the given value in the previous control cycle, Ref k+1 It is the current control setpoint, U P It is a proportional control quantity, U I It is the integral control variable, U D U is the differential control quantity, U is the PID control quantity, and α is the phase-controlled rectifier bridge control angle.

[0005] In steady state, the control deviation obtained by the online controller according to formula (1) is close to 0, and the U obtained by formulas (2) and (3) is close to 0. P U D If the value is close to 0, then formula (5) yields an output control quantity that is basically the same as U. I Consistent. If the backup controller U I Equal to the online control channel, and the input deviation ΔV obtained according to formula (1) is always 0, and the U obtained according to formulas (2) and (3) is... P U D If the output control quantity is equal to 0, then formula (5) yields the output control quantity U, which equals U. I .

[0006] When switching control in the online system, the standby controller becomes the online controller, the setpoint remains at the current value, and the measured value is no longer tracked. At this time, the control deviation obtained according to formula (1) is close to 0, and the U obtained from formulas (2) and (3) is... P U D If the value is close to 0, then formula (5) yields an output control quantity that is basically the same as U. I Consistent means that the control quantity does not change significantly during channel switching, and there is basically no disturbance.

[0007] Figure 2 In the cascaded PID transfer function, T 11 <T 12 As part of the scoring process, T 13 >T 14 As a differentiating element, K represents the gain. The discretization implementation method in the control program is as follows: Input signal: (7) Where, ΔV k+1 It is the current control deviation, V. k+1 It is the current measurement value of the controlled object, Ref k+1 It is the currently given value.

[0008] Points system: (8) (9) Where Δt is the control period, and ΔV k+1 This is the current control deviation value; u k+1 It is the intermediate state quantity of the integral element obtained from the current calculation, u k It is the intermediate state quantity of the integral element obtained from the previous control cycle; y k+1 It is the output value of the integration stage.

[0009] Differential component: (10) (11) Where Δt is the control period, y k+1 This is the output value of the current integration stage, y k It is the output value of the integral element in the previous control cycle; It is the intermediate state quantity of the differential element obtained from the current calculation. It is the intermediate state quantity of the differential element obtained in the previous control cycle; It is the output value of the differential element.

[0010] Output control quantity: (12) Where U is the control quantity calculated by PID control, and K is the PID control gain. It is the output value of the differential element.

[0011] For online controllers, if the integral element u k+1 0, differential element The integral term outputs y when the input deviation ΔV is always 0. k+1 The value is 0, and the differential element is... If the value is 0, the output control quantity U of the cascaded PID controller is 0.

[0012] For a controller using a series PID controller, the control deviation obtained by the online controller according to formula (1) in steady state is close to 0. The input deviation obtained by the standby controller according to formula (1) when the setpoint tracks the measured value is always 0. If the PID parameters of the standby controller are the same as those of the online controller, then the standby controller uses the uk of the online control channel, and the u obtained according to formulas (8) and (9) k+1 y k+1 It is essentially the same as the online controller; furthermore, if the standby controller uses the online controller's... Then the two control channels are obtained according to formulas (10), (11), and (12). , It is basically the same as U.

[0013] When online control is switched, the standby controller becomes the online controller, maintaining the current setpoint and no longer tracking the measured value. Before gaining online control, the standby controller uses the intermediate state variable u from the online controller's integral stage. k+1 and intermediate state quantities of the differential element Replace their own data, that is, the u of the two controllers when online control switching occurs. k+1 and intermediate state quantities of the differential element Since the deviation obtained by the controller that loses online control at the moment of switching is close to 0 according to formula (1), and the deviation obtained by the controller that gains online control according to formula (1) is equal to 0, the output control quantity U obtained by the two controllers according to formula (12) is basically the same. Therefore, there is basically no disturbance at the moment of switching online control.

[0014] In summary, there is an urgent need for a technical solution to address the coordination and control challenges of distributed multi-controller systems. Summary of the Invention

[0015] To address the aforementioned issues, this disclosure provides an online weight switching control method for a high-redundancy excitation system.

[0016] Firstly, a method for online weight switching control of a high-redundancy excitation system includes: The excitation system comprises two control channels of the excitation regulating cabinet and multiple power cabinets with configured controllers. All controllers are interconnected via fiber optic cables, and only one is allowed to be in online control mode at a time. The control channels have high priority, the power cabinets have low priority, and devices with the same priority have sub-priority settings. The control strategy includes: When the online control channel communicates normally with at least one power cabinet, the power cabinet controller cannot compete for online control. When the number of power cabinets that are communicating normally with a certain controller is greater than the number of power cabinets that are communicating normally with the online controller, and this controller is able to participate in the competition for online control, then this controller obtains online control. If multiple controllers meet the above conditions and have the same priority, the online delay is set according to the sub-priority, and the controller with the shortest delay gets the online control. When a low-priority controller is in online control, if the high-priority controller recovers to normal, the high-priority controller is allowed to automatically gain online control only when the excitation system is in a static state with no output. Otherwise, manual intervention is required for the high-priority controller to gain online control. If the communication between the power cabinet controller and the online controller is interrupted, and other power cabinet controllers are communicating normally with the online controller, this power cabinet will stop outputting.

[0017] Furthermore, the sub-priority of the first control channel is 0, and the sub-priority of the second control channel is 1; the sub-priority of the power cabinet is consistent with the sequence number, and the sub-priority of power cabinet n is n.

[0018] Furthermore, the conditions for participating in the struggle for online control include: The control channel can only participate in the contest for online control when it is in normal communication with at least one power cabinet. A power cabinet can only compete for online control when all power cabinets simultaneously fail to communicate with both control channels.

[0019] Furthermore, the online control contention logic during controllerless online control includes: If an excitation regulating cabinet control channel participates in the contention, the control channel will switch to an online controller after a delay based on a multiple of the sub-priority. For example, the online delay is set to 80 + 40 × sub-priority milliseconds. The sub-priority with the smaller priority has a higher priority and a shorter online delay. If only power cabinets participate in the contention, the power cabinets will switch to online controllers after a delay based on a multiple of the sub-priority. For example, the online delay can be set to 20 × sub-priority milliseconds, with the sub-priority being lower and thus having a shorter online delay.

[0020] Furthermore, the exit logic when multiple controllers are online simultaneously includes: If both the excitation regulating cabinet control channel and the power cabinet are online at the same time, the online power cabinet will immediately exit the online control state. If two excitation regulating cabinet control channels are online simultaneously, or multiple power cabinets are online simultaneously, the online controller will exit the online control state after a delay based on a multiple of the sub-priority. For example, the online controller is set to exit with a delay of 120-20 times the sub-priority milliseconds. The controller with the lower sub-priority in the online control state will have a longer delay before exiting the online control state.

[0021] Furthermore, the conditions for an online controller to exit the online control state include: If the number of power cabinets communicating normally with the online controller is not the highest among the controllers capable of competing for online control, the online controller will immediately exit the online control state.

[0022] Furthermore, it also includes: If the number of power cabinets that are communicating normally with a certain controller is greater than the number of online controllers, and this controller is able to compete for online control, the controllers that are able to compete for online control first compare the number of power cabinets that are communicating normally with it, and the controller with the most power cabinets that are communicating normally with it wins online control. If multiple controllers have the same maximum number of power cabinets with normal communication, the device with the lowest sub-priority will gain online control after a delay equal to a multiple of its sub-priority. For example, if the online delay is set to 20 times the sub-priority milliseconds, the controller will enter online control mode. After a controller with a lower sub-priority gains online control, other controllers vying for online control will no longer be able to compete for control if they detect that an existing controller is online and has the same number of power cabinets with which it has normal communication.

[0023] Furthermore, it also includes: When the power cabinet is under online control, if a certain control channel of the excitation regulating cabinet returns to normal and can participate in the competition for online control, then this control channel is allowed to automatically obtain online control only when the excitation system has no output. Otherwise, this control channel can only be set as an online controller through manual intervention.

[0024] Furthermore, all controllers employ PID control algorithms with identical principles and parameters to achieve excitation control. Each controller sends status data to other controllers at least once per power frequency cycle. The status data exchanged between controllers includes the phase-controlled rectifier bridge firing angle, controller communication status, online control status, and intermediate state quantities of the PID algorithm. In standby mode, the standby controller tracks its own analog measurement value with the given value and uses the intermediate state quantities of the PID algorithm of the online controller for calculation.

[0025] Furthermore, before the power cabinet starts sending data, it searches for whether each controller is online in descending order of priority and sub-priority, and uses the trigger angle of the first online controller found as the trigger angle for its own execution.

[0026] Furthermore, the communication fault determination and handling logic is as follows: If no data is received from a controller within a preset time period (e.g., 200 milliseconds for the control channel and 80 milliseconds for the power cabinet), it is determined that communication with this controller is interrupted, the online flag of this controller is cleared, and the communication status of this controller with other controllers is set to fault status. When communication between the power cabinet and the online controller is interrupted, and other power cabinets are communicating normally with the online controller, this power cabinet stops outputting.

[0027] This disclosure includes at least the following beneficial effects: This disclosure presents an excitation regulating cabinet with two control channels and multiple intelligent power cabinets with configured controllers, all interconnected via optical fiber. The control channels are designated as high priority, and the intelligent power cabinets as low priority, incorporating sub-priority and communication status monitoring mechanisms. The strategy stipulates that the power cabinet can only participate in control contention when all communication between the control channels and the power cabinet fails; control ownership is determined based on the number of controllers with normal communication and sub-priority delays; when a low-priority controller is online, a high-priority controller can automatically take over control only in a static state. Furthermore, this disclosure achieves bumpless switching through interactive PID intermediate state variables and specifies isolation and exit mechanisms in case of communication failures. This strategy effectively solves the coordination control problem of distributed multi-controller systems, significantly improving the operational reliability, safety, and redundancy of the excitation system.

[0028] Other features and advantages of this disclosure will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the disclosure. The objects and other advantages of this disclosure may be realized and obtained by means of the structures pointed out in the description and the accompanying drawings. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the transfer function of a parallel PID controller; Figure 2 This is a schematic diagram of the transfer function of a series PID controller; Figure 3 This is a schematic diagram of the excitation system according to an embodiment of the present disclosure; Figure 4 This is a schematic diagram illustrating the switching of online control channels due to communication failure in an embodiment of this disclosure; Figure 5 This is a schematic diagram illustrating that a communication failure did not lead to a switch of the online control channel in an embodiment of this disclosure; Figure 6 This is a schematic diagram showing how control channel 2 gains online control after control channel 1 fails, according to an embodiment of this disclosure. Figure 7 This is a schematic diagram showing that control channel 1 gains online control after a communication failure occurs in power cabinet 1 according to an embodiment of this disclosure; Figure 8 This is a schematic diagram illustrating how a communication interruption between control channels can cause multiple controllers to be online simultaneously, according to an embodiment of this disclosure. Figure 9This is a schematic diagram illustrating the control channel's struggle for online control after power-on initialization, as per an embodiment of this disclosure. Figure 10 This is a schematic diagram showing the three power cabinets vying for online control after control channel 1 is taken out of operation according to an embodiment of this disclosure. Figure 11 This is a schematic diagram illustrating the online control switchover caused by a communication failure between power cabinets in the power cabinet system of this embodiment. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0032] like Figure 3 As shown, an online weight switching control method for a high-redundancy excitation system includes: The excitation system includes two control channels of the excitation regulating cabinet and a power cabinet for configuring controllers. All controllers are interconnected via fiber optic cables, and only one controller is allowed to be in online control mode at a time. The control channels have high priority, the power cabinet has low priority, and devices with the same priority have sub-priority settings. The control strategy includes: When the control channel is online and the online control channel communicates normally with at least one power cabinet, the power cabinet controller cannot compete for online control. When the number of power cabinets that are communicating normally with a certain controller is greater than the number of power cabinets that are communicating normally with the online controller, and this controller is able to participate in the competition for online control, then this controller obtains online control. If multiple controllers meet the above conditions and have the same priority, the online delay is set according to the sub-priority. For example, the control channel is set to 80 + 40 × sub-priority milliseconds delay, and the power cabinet is set to 20 × sub-priority milliseconds delay. The controller with the shorter delay gets the online control right. When the low-priority controller (power cabinet) is in online control, if the high-priority controller (control channel) returns to normal, the high-priority controller is allowed to automatically obtain online control only when the excitation system has no output and is in a static state. Otherwise, manual intervention is required for the high-priority controller to obtain online control. If the power cabinet controller loses communication with the online controller, and another power cabinet controller is communicating normally with the online controller, this power cabinet will stop outputting.

[0033] The specific implementation details are as follows: This disclosure clarifies the content and purpose of the interactive information between controllers in a high-redundancy excitation control system, the fault criteria when switching online control rights, the special operating condition where a high-priority controller automatically gains online control rights after recovery, and the control strategy for a faulty power cabinet.

[0034] The controller has analog sampling function and can perform excitation control according to the controlled object.

[0035] All controllers use the same PID control algorithm with identical principles and parameters. Each power frequency cycle transmits its own state quantity via optical fiber, which includes the intermediate state quantity of the PID algorithm: if it is a parallel PID, it transmits the integral control quantity; if it is a series PID, it transmits the intermediate state quantity of the integral and derivative elements.

[0036] When in standby mode, the standby controller tracks its own analog measurement value and uses the intermediate state quantity of the online controller's PID algorithm for PID calculation, so that the online control handover process is almost disturbanceless.

[0037] The self-state variables transmitted via optical fiber include the controller's communication status with other controllers and its online control status. The communication status is an internal flag within the controller; each controller in the high-redundancy excitation system is assigned a flag bit, which is 1 when data is received from the other controller and 0 when no valid data is received within 100 milliseconds. The online control status is also an internal flag bit within the controller, which is 1 during online control and 0 during standby.

[0038] The controller determines whether the other controller has received its data and whether it is operating online by analyzing data received from the other controller. It also counts the number of power cabinets that are communicating normally with the other controller. If both the receiver and the transmitter are power cabinet controllers, the receiver also needs to determine whether the other controller is communicating normally with the excitation regulating cabinet control channel. When there is a need for online control switching, the control channel takes priority.

[0039] The self-state variables transmitted via optical fiber include the trigger angle obtained from the excitation control algorithm. Before the power cabinet starts sending data, it sequentially checks whether each controller is online according to its priority and sub-priority from high to low. First, it checks control channel 1, then control channel 2, and then the power cabinets according to their sequence numbers from low to high. The trigger angle of the first online controller found is used as the trigger angle for its own execution.

[0040] Communication failure is the primary cause of online control switching. A failure to receive data from a controller for 100 consecutive milliseconds is considered a communication failure with that controller. The cause could be a problem with the communication line, a power outage, or a restart of the controller. For controllers experiencing communication failures, their status will be cleared: the controller will be set to offline control mode, and the number of power cabinets with which it has normal communication will be reduced to 0.

[0041] The control channel has the highest control priority, with control channel 1 having a sub-priority of 0 and control channel 2 having a sub-priority of 1. The switching of online control rights between control channels includes the same switching conditions as the classic dual-channel excitation system without intelligent power cabinets: PT disconnection in the online control channel, or a channel switching command from the HMI or channel switching button. There are also unique switching conditions for high-redundancy excitation systems using intelligent power cabinets: the number of power cabinets with normal communication with a control channel is lower than that of the other control channel due to a communication failure with a certain power cabinet. For example... Figure 4 As shown, in an excitation system configured with 3 power cabinets, the online control channel 1 and power cabinet 3 experience communication failure. At this time, the number of power cabinets communicating normally with control channel 1 is 2, which is less than the number of power cabinets communicating normally with control channel 2 (3). Therefore, the online control will be switched to control channel 2.

[0042] If the number of power cabinets that can communicate normally with a power cabinet after a communication failure on the online control channel is not less than the number of power cabinets that can communicate normally with another control channel, then no online control channel switching will occur. Figure 5 As shown, control channel 2 communicates normally with only two power cabinets. After the communication between online control channel 1 and power cabinet 3 fails, the number of power cabinets communicating normally with it remains the same as that of control channel 2, and online control will not switch. At this time, communication between power cabinets is normal, and the number of power cabinets communicating normally with each power cabinet is 3, which is greater than the number of 2 corresponding to the control channel. The communication between the control channel and the power cabinets has not failed simultaneously, so the power cabinets cannot participate in the competition for online control. Under this condition, power cabinet 3 will stop outputting because it has lost contact with the online control channel.

[0043] Intelligent power cabinets are only allowed to compete for online control when all power cabinets simultaneously experience communication failures with both control channels. For example... Figure 6 As shown, control channel 1 communicates normally with all power cabinets, while control channel 2 only communicates normally with power cabinet 3. Communication between power cabinets is normal. At this point, control channel 1 exits operation, and all communication between the controllers and control channel 1 fails. Power cabinets 1 and 2 detect through the status data of power cabinet 3 that power cabinet 3 is communicating normally with control channel 2. Therefore, all power cabinets are unable to compete for online control, and control channel 2 subsequently gains online control. Power cabinets 1 and 2 will stop outputting due to the loss of connection with the online controller, while only power cabinet 3 will output normally under the control of control channel 2.

[0044] For example Figure 7As shown, the current excitation system is controlled online by power cabinet 1 and is in output mode. Control channel 1 has returned to normal, but only maintains normal communication with power cabinet 1. If the excitation system is in a static state before output, power cabinet 1 will relinquish online control, and control channel 1 will gain online control. If the excitation system is in output mode, power cabinet 1 will maintain online control. If communication between power cabinet 1 and power cabinet 3 fails at this time, the number of power cabinets communicating normally with power cabinet 1 will be 2, which is no longer the maximum in the current controller, and power cabinet 1 will exit online control mode. At this time, all power cabinets can detect through the power cabinet 1 status data that control channel 1 is communicating normally with power cabinet 1 and cannot participate in the competition for online control. When all controllers are offline, control channel 1 gains online control after a delay.

[0045] When multiple devices are controlled online simultaneously, if both a control channel and a power cabinet are online at the same time, the power cabinet under online control should immediately shut down. If all controllers are of the same priority, a delay of 120-20 × sub-priority milliseconds should be set to exit the online control state. For example... Figure 8 As shown, when control channel 1 is in online control, communication between control channels 1 and 2 is interrupted, causing control channel 2 to switch to online control. When communication is restored, the control channel detects that both channels are in online control simultaneously. Control channel 1, with a sub-priority of 0, will exit the online control state after a delay of 120 milliseconds. Control channel 2, with a sub-priority of 1, will exit the online control state after a delay of 100 milliseconds. Ultimately, control channel 2 exits the online control state. Control channel 1 will detect that only it is currently in online control of the excitation system before exiting the online control state, and therefore does not need to exit the online control state.

[0046] In online control without a controller, the controllers vying for online control will set an online delay based on sub-priority, and the controller with the shorter delay will gain online control. For example... Figure 9 As shown, when the excitation system is powered on, all controllers are initially in an offline control state. At this time, because the communication between the control channel and the power cabinet is normal, the power cabinet cannot participate in the competition for online control. The control channel will set the online delay to 80 + 40 × sub-priority milliseconds, that is, control channel 1 delays for 80 milliseconds, control channel 2 delays for 120 milliseconds, and finally control channel 1 gains online control due to its shorter delay.

[0047] like Figure 10As shown, currently only control channel 1 is online, while control channel 2 is offline. Communication between all devices is currently normal. When control channel 1 also goes offline, all power cabinets will lose contact with both control channels, allowing them to compete for online control. The power cabinets will set their online delay to 20 × sub-priority milliseconds. The online delays for the three power cabinets are 20 milliseconds, 40 milliseconds, and 60 milliseconds, respectively. Ultimately, power cabinet 1 gains online control due to its shortest online delay.

[0048] like Figure 11 As shown: In an excitation system configured with 4 power cabinets, two control channels of the excitation regulating cabinet are out of operation. When power cabinet 1 is in online control, communication with power cabinet 3 is interrupted. At this time, the number of power cabinets communicating normally with power cabinet 1 is no longer the maximum value in the current controller, and power cabinet 1 will exit the online control state. At this time, the number of power cabinets communicating normally with power cabinets 2 and 4 is the maximum value of 4. Power cabinets 2 and 4 will set their online delay to 20 × sub-priority milliseconds, with power cabinet 2's online delay at 40 milliseconds and power cabinet 4's at 80 milliseconds. Ultimately, power cabinet 4 will gain online control due to its shorter online delay.

[0049] To enable those skilled in the art to better understand this disclosure, the principles of this disclosure are explained below in conjunction with the accompanying drawings: like Figure 3 As shown, the high-redundancy excitation system controller is divided into two priorities: the two control channels of the excitation regulating cabinet are of high priority, and the intelligent power cabinet controller is of low priority. Devices with the same priority have preset sub-priorities. When the online control channel communicates normally with at least one power cabinet, the power cabinet controller cannot compete for online control. If the number of normal controllers communicating with a certain controller is greater than the number of normal controllers communicating with the online controller, and this controller can participate in the competition for online control, then the controller with the most normal controllers communicating with it gains online control. If multiple controllers simultaneously meet the above conditions and are of the same priority, all capable of competing for online control, then the online delay is set according to the sub-priority, and the controller with the shorter delay gains online control. When a low-priority controller is in online control, if the high-priority controller recovers, the high-priority controller is only allowed to automatically gain online control under static conditions; otherwise, it can only gain online control through manual intervention. If the communication between the power cabinet controller and the online controller is interrupted, and other power cabinet controllers are communicating normally with the online controller, this power cabinet stops outputting.

[0050] Online weight switching control strategy for high-redundancy excitation systems: In the high-redundancy excitation system, the two control channels of the excitation regulating cabinet have high priority, with control channel 1 having a sub-priority of 0 and control channel 2 having a sub-priority of 1. The intelligent power cabinet equipped with a controller has low priority, and the sub-priority of the power cabinet is consistent with its serial number: power cabinet n has a sub-priority of n. All controllers are interconnected via optical fiber and can independently perform analog quantity measurements. They all use the same PID control algorithm with identical principles and parameters to achieve excitation control, and only one controller is allowed to be in online control mode at a time.

[0051] Each controller sends status data to other controllers at least once per power frequency cycle. The outgoing status information includes the phase-controlled rectifier bridge firing angle, controller communication status, online control status, and intermediate status quantities of the PID algorithm.

[0052] Before all power cabinets fail to communicate with two control channels simultaneously, the power cabinets cannot compete for online control; they can only compete for online control when at least one control channel is communicating normally with one power cabinet.

[0053] When there is no controller online, if the excitation regulating cabinet control channel communicates normally with at least one power cabinet, the control channel is set to switch to online controller with a delay of 80 + 40 × sub-priority milliseconds; if only the power cabinet can participate in the competition for online control, the power cabinet is set to switch to online controller with a delay of 20 × sub-priority milliseconds.

[0054] When multiple controllers are online simultaneously, if there is an excitation regulating cabinet control channel online, the power cabinet under online control will immediately exit the online control state. If two excitation regulating cabinet control channels are online simultaneously, or multiple power cabinets are online simultaneously, i.e. multiple controllers with the same priority are online simultaneously, the controller under online control will exit the online control state after a delay of 120-20 × sub-priority milliseconds.

[0055] If the number of power cabinets that are normally communicating with the controller in online control is not the highest among the controllers that can compete for online control, this controller will immediately exit the online control state.

[0056] If the number of power cabinets communicating normally with a certain controller is greater than the number of online controllers, and this controller is able to compete for online control, the controllers that are able to compete for online control will first compare the number of power cabinets communicating normally with them. The controller with the most power cabinets communicating normally with them will obtain online control. If multiple controllers have the same maximum number of power cabinets communicating normally, the online delay will be set according to the sub-priority, which is the sub-priority multiplied by 20 milliseconds. The device with the shorter delay, i.e., the device with the lower sub-priority, will obtain online control.

[0057] When the power cabinet is under online control, if a certain control channel of the excitation regulating cabinet returns to normal and can participate in the competition for online control, then this control channel is allowed to automatically obtain online control only when the excitation system has no output. Otherwise, this control channel can only be set as an online controller through manual intervention.

[0058] Before the power cabinet starts sending data, it searches for the online status of each controller in descending order of priority and sub-priority, and uses the trigger angle of the first online controller found as the trigger angle for its own execution.

[0059] If no data is received from a controller for 100 consecutive milliseconds, it is determined that communication with that controller is interrupted. The online flag of that controller is cleared, and the communication status of this controller with all other controllers is set to fault status.

[0060] When communication between the power cabinet and the online controller is interrupted, and other power cabinets are communicating normally with the online controller, this power cabinet stops outputting.

[0061] Although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A method for online weight switching control of a high-redundancy excitation system, characterized in that, include: The excitation system includes two control channels of the excitation regulating cabinet and a power cabinet for configuring controllers. All controllers are interconnected via fiber optic cables, and only one controller is allowed to be in online control mode at a time. The control channels have high priority, the power cabinet has low priority, and devices with the same priority have sub-priority settings. The control strategy includes: When the online control channel communicates normally with at least one power cabinet controller, the power cabinet controller cannot compete for online control. When the number of power cabinets that are communicating normally with a certain controller is greater than the number of power cabinets that are communicating normally with the online controller, and this controller is able to participate in the competition for online control, then this controller obtains online control. If multiple controllers with the same priority gain online control, the online delay is set according to the sub-priority, and the controller with the shortest delay gains online control. When a low-priority controller is in online control, if the high-priority controller recovers to normal, the high-priority controller is allowed to automatically gain online control only when the excitation system is in a static state with no output; otherwise, manual intervention is required. If the communication between the power cabinet controller and the online controller is interrupted, and other power cabinet controllers are communicating normally with the online controller, this power cabinet will stop outputting.

2. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, The sub-priority of the first control channel is 0, and the sub-priority of the second control channel is 1; the sub-priority of the power cabinet is consistent with the sequence number, and the sub-priority of power cabinet n is n.

3. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, The conditions for participating in the struggle for online control include: The control channel can only participate in the contest for online control when it is in normal communication with at least one power cabinet. A power cabinet can only compete for online control when all power cabinets simultaneously fail to communicate with both control channels.

4. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, The online control logic in controllerless online control includes: If an excitation regulating cabinet control channel participates in the contention, the control channel will switch to an online controller after a delay based on the sub-priority multiple; If only power cabinets participate in the contention, the power cabinets will switch to online controllers after a delay based on the sub-priority multiple.

5. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, The exit logic when multiple controllers are online simultaneously includes: If both the excitation regulating cabinet control channel and the power cabinet are online at the same time, the online power cabinet will immediately exit the online control state. If two excitation regulating cabinet control channels are online simultaneously, or multiple power cabinets are online simultaneously, the online controller will exit the online control state after a delay based on the sub-priority multiple.

6. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, The conditions for an online controller to exit online control status include: If the number of power cabinets communicating normally with the online controller is not the highest among the controllers capable of competing for online control, the online controller will immediately exit the online control state.

7. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, Also includes: If the number of power cabinets that are communicating normally with a certain controller is greater than the number of online controllers, and this controller is able to compete for online control, the controllers that are able to compete for online control first compare the number of power cabinets that are communicating normally with it, and the controller with the most power cabinets that are communicating normally with it wins online control. If multiple controllers have the same maximum number of power cabinets with normal communication, the device with the lowest sub-priority will gain online control after a delay equal to the sub-priority multiple.

8. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, Also includes: When the power cabinet is under online control, if a certain control channel of the excitation regulating cabinet returns to normal and can participate in the competition for online control, then this control channel is allowed to automatically obtain online control only when the excitation system has no output. Otherwise, this control channel can only be set as an online controller through manual intervention.

9. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, All controllers use the same PID control algorithm with identical parameters to achieve excitation control. Each controller sends status data to other controllers at least once per power frequency cycle. The status data exchanged between controllers includes the phase-controlled rectifier bridge firing angle, controller communication status, online control status, and intermediate state quantities of the PID algorithm. When in standby mode, the standby controller tracks its own analog measurement value with the given value and uses the intermediate state quantities of the PID algorithm of the online controller for calculation.

10. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, Before the power cabinet starts sending data, it searches for the online status of each controller in descending order of priority and sub-priority, and uses the trigger angle of the first online controller found as the trigger angle for its own execution.

11. The online weight switching control method for a high-redundancy excitation system according to claim 1, characterized in that, The communication fault diagnosis and handling logic is as follows: If no data is received from a controller for a continuous preset time, it is determined that the communication with this controller is interrupted, the online flag of this controller is cleared, and the communication status of this controller with all other controllers is set to fault status. When communication between the power cabinet and the online controller is interrupted, and other power cabinets are communicating normally with the online controller, this power cabinet stops outputting.

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