A high-frequency control method and system for an intelligent power cabinet

Abstract

This disclosure relates to the field of intelligent power cabinet control technology, and particularly to a high-frequency control method and system for intelligent power cabinets. In the excitation system with intelligent power cabinets, the intelligent power cabinets need to communicate with the excitation regulating cabinet at high frequency to ensure the execution frequency of control. The power cabinet control module, as the active party in the responsive communication, first checks whether it has received data from the excitation regulating cabinet control channel during a trigger pulse interrupt. If data is received, it refreshes the control angle according to the online control channel data, then sets the current pulse delay according to the trigger angle, and finally immediately sends its own data to the excitation regulating cabinet control channel. This disclosure executes communication between the power cabinet and the regulating cabinet during a pulse interrupt, which can greatly improve the communication frequency between the two and also ensure that each power cabinet outputs a trigger pulse based on the same control angle.

Description

Technical Field

[0001] This disclosure relates to the field of intelligent power cabinet control technology, and in particular to a high-frequency control method and system for an intelligent power cabinet. 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 power cabinets, intelligent current sharing schemes have emerged. Current technology equips the power cabinets with controllers. The excitation regulating cabinet's control channel sends the trigger angle to the power cabinets via communication, and the power cabinets generate their own trigger pulses. This allows the power cabinets to fine-tune the trigger angle based on their own output current, ensuring consistent output current. In intelligent current sharing schemes, this type of power cabinet with a controller is called an intelligent power cabinet. In this case, the excitation control calculation is performed by the regulating cabinet, and the control results are executed by the intelligent power cabinet. The communication frequency between the power cabinet and the regulating cabinet is a crucial factor determining the excitation control frequency.

[0003] Intelligent power cabinets require high-speed communication with the online control channel of the regulating cabinet, and all power cabinets must synchronously refresh their control angles. If power cabinets execute different control angles, it will cause output abnormalities. Existing technology uses a communication method driven by a specific phase synchronization signal, where the power cabinet actively sends data during a synchronization interruption, and the regulating cabinet's control channel responds. This allows the regulating cabinet and power cabinets to complete one communication cycle per period, enabling all power cabinets to synchronously refresh their control angles. However, this communication method also limits the control frequency. Although the excitation regulating cabinet can perform control calculations at higher frequencies, due to the communication frequency limitation, it can only execute once per power frequency cycle.

[0004] The implementation scheme of intelligent power cabinet output trigger pulse, such as Figure 1 As shown, the rising edge of the A-phase synchronization signal is generally used as the starting point of the current cycle. The control angle interrupt delay of Timer 1 is set. In the control angle interrupt, in addition to outputting the first pair of trigger pulses, a 60° interrupt delay of Timer 2 is also set. Subsequent pulses are output sequentially in the 60° interrupt of Timer 2. If the A-phase synchronization signal fails and switching to another phase is required, the pulses output in each interrupt need to be adjusted according to the synchronization phase to adapt to the phase change. For example, when using B-phase synchronization, a third pair of pulses needs to be output in the control angle interrupt.

[0005] The time difference between the rising edges of two in-phase synchronization signals is the current period, corresponding to 360°. Therefore, the formula for converting the control angle into a delay is as follows:

[0006] Where t is the delay corresponding to the control angle, T is the current period, and α is the control angle.

[0007] The existing solution uses the same control angle for all six timing pulse interruptions within a cycle, resulting in slow response and a control frequency of only 50Hz at power frequency. If the pulse phase could be adjusted according to the new control angle every three pulse interruptions, the control frequency could reach 100Hz. Furthermore, if the phase of each pulse interruption could be adjusted according to the new control angle, the control frequency could reach the upper limit of 300Hz for a phase-controlled rectifier bridge.

[0008] In conclusion, there is an urgent need for a control scheme with a faster response speed. Summary of the Invention

[0009] To address the aforementioned issues, this disclosure provides a high-frequency control method and system for an intelligent power cabinet.

[0010] Firstly, a high-frequency control method for an intelligent power cabinet. The settings are configured in the pulse interrupt service routine of the timer via the intelligent power cabinet, including: Record the moment of the synchronous interrupt as the starting point of the current cycle in the synchronous interrupt; In the pulse interrupt service routine, first check if the synchronization time has been refreshed. If it has been refreshed, set the synchronization refresh flag; otherwise, prohibit the output of pulse in the current cycle. Check if data is received from the online control channel of the excitation regulating cabinet. If received, refresh the control angle according to the data. If not received, use the previous control angle. Collect its own status data and send the data to the excitation control cabinet; After data communication is completed, determine whether excitation output is needed. If so, set and output the trigger pulse according to the current pulse sequence number.

[0011] Furthermore, the synchronization interrupt time is recorded as the starting point of the current cycle in the synchronization interrupt, including: When the current phase is the synchronous phase of the drive trigger pulse, record the interrupt time; Set a synchronization time change flag, and use the interrupt time as the start point of the cycle to provide pulse interrupt alignment pulses.

[0012] Furthermore, the pulse interrupt uses a timer interrupt, triggering six communications and pulse outputs within each power frequency cycle; the number of communications per power frequency cycle is determined by the multiple of the limit control frequency and the power frequency.

[0013] Furthermore, each pulse interruption completes a data communication with the excitation control cabinet and a control angle refresh.

[0014] Furthermore, after completing six pulse outputs in this cycle, the synchronization refresh flag is cleared.

[0015] Furthermore, the synchronous interrupt time is used to align the trigger pulses, and the delay setting of the first pair of trigger pulses in this cycle is completed when the sixth pair of pulses is output in the previous cycle.

[0016] Furthermore, the method requires that the change in the control angle be no less than the preset angle to ensure that the time interval between two adjacent pulse interruptions meets the requirements.

[0017] Secondly, a high-frequency control system for an intelligent power cabinet. The settings are configured in the pulse interrupt service routine of the timer via the intelligent power cabinet, including: The system includes a synchronous interruption time recording unit, a synchronous refresh unit, a control angle refresh unit, a data transmission unit, and an excitation output unit. The synchronous interruption time recording unit is used to record the synchronous interruption time as the starting point of the current cycle. The synchronous refresh unit is used in the pulse interrupt service routine to first detect whether the synchronous time has been refreshed. If it has been refreshed, the synchronous refresh flag is set; otherwise, the output pulse for the current cycle is prohibited. The control angle refresh unit is used to detect whether data is received from the online control channel of the excitation regulating cabinet. If data is received, the control angle is refreshed according to the data; if no data is received, the previous control angle is used. The data transmission unit is used to collect its own status data and send the data to the excitation control cabinet; The excitation output unit is used to determine whether excitation output is needed after data communication is completed. If so, it sets and outputs a trigger pulse according to the current pulse sequence number.

[0018] Furthermore, the synchronization interrupt time is recorded as the starting point of the current cycle in the synchronization interrupt, including: When the current phase is the synchronous phase of the drive trigger pulse, record the interrupt time; Set a synchronization time change flag, and use the interrupt time as the start point of the cycle to provide pulse interrupt alignment pulses.

[0019] Furthermore, the pulse interrupt uses a timer interrupt, triggering six communications and pulse outputs within each power frequency cycle; the number of communications per power frequency cycle is determined by the multiple of the limit control frequency and the power frequency.

[0020] This disclosure includes at least the following beneficial effects: This disclosure performs communication between the power cabinet and the regulating cabinet in a pulse interrupt, which can greatly improve the communication frequency between the two and also ensure that each power cabinet outputs a trigger pulse based on the same control angle.

[0021] In the excitation system with intelligent power cabinet disclosed in this invention, the intelligent power cabinet needs to communicate with the excitation regulating cabinet at high frequency to ensure the execution frequency of control. The power cabinet control module, acting as the active party in the responsive communication, first checks whether it has received data from the excitation regulating cabinet control channel during the trigger pulse interrupt. If data is received, it refreshes the control angle according to the online control channel data, then sets the current pulse delay according to the trigger angle, and finally immediately sends its own data to the excitation regulating cabinet control channel. The excitation regulating cabinet control channel detects the power cabinet's data transmission in a 1-millisecond periodic task. After completing the first power cabinet data reception, it initiates the current data transmission to the power cabinet. The control channel completes the current data transmission when it receives all power cabinet data or after 2 milliseconds since completing the first power cabinet data reception. When sending the first pair of pulses, the intelligent power cabinet checks whether the synchronization time has been refreshed; if not, it does not output a pulse.

[0022] 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

[0023] 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.

[0024] Figure 1 This is a schematic diagram of pulse generation; Figure 2 This is a schematic diagram of the control method flow according to an embodiment of the present disclosure; Figure 3 A schematic diagram of the internal communication network of the excitation system configured with three intelligent power cabinets according to an embodiment of this disclosure; Figure 4 This is a schematic diagram of the synchronization interruption service procedure according to an embodiment of the present disclosure; Figure 5 This is a schematic diagram of the synchronization signal according to an embodiment of the present disclosure. Detailed Implementation

[0025] 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.

[0026] like Figure 2 As shown, a high-frequency control method for an intelligent power cabinet is described. The settings are configured in the pulse interrupt service routine of the timer via the intelligent power cabinet, including: Record the moment of the synchronous interrupt as the starting point of the current cycle in the synchronous interrupt; In the pulse interrupt service routine, first check if the synchronization time has been refreshed. If it has been refreshed, set the synchronization refresh flag; otherwise, prohibit the output of pulse in the current cycle. Check if data is received from the online control channel of the excitation regulating cabinet. If received, refresh the control angle according to the data. If not received, use the previous control angle. Collect its own status data and send the data to the excitation control cabinet; After data communication is completed, determine whether excitation output is needed. If so, set and output the trigger pulse according to the current pulse sequence number.

[0027] The specific implementation details are as follows: The two control channels of the intelligent power cabinet and the excitation regulation cabinet are interconnected through a communication network, such as... Figure 3 The excitation system shown is configured with three power cabinets, and the control modules are interconnected.

[0028] Currently, phase-controlled rectifier bridges generally use three-phase six-pulse rectification, with a lower limit control frequency of 300Hz at a 50Hz power frequency. This means that the phase of each pulse can be adjusted according to the latest control angle. While current MCUs (Micro Controller Units) can meet the calculation requirements for a 300Hz control frequency, if the communication frequency between the excitation system regulating cabinet control channel and the power cabinet does not reach 300Hz, the power cabinet's execution frequency will also be unable to reach 300Hz.

[0029] This patent proposes a pulse-driven high-frequency control scheme. In the pulse interrupt service routine of the timer, the power cabinet performs a reception detection before setting the pulse output. If data from the online control channel is received, the control angle is refreshed accordingly. Then, the timer delay is set according to the current control angle and the synchronous interrupt time. Next, the current trigger pulse is output, and finally, the power cabinet starts sending data to the excitation regulating cabinet control channel.

[0030] First, the timing of the synchronization interrupt needs to be recorded in the synchronization interrupt as the starting point of the current cycle. The process is as follows: Figure 4 As shown.

[0031] Synchronous interrupts need to record the interrupt time as the starting point of the cycle for pulse interrupt alignment pulses.

[0032] The pulse interrupt is a timer interrupt. Each pulse interrupt cycle requires six communication and pulse outputs. Once started, the timer will not stop regardless of whether output is needed or whether there is a synchronization signal.

[0033] like Figure 2 As shown, when the first pair of pulses is about to be output, the system checks whether the synchronization time has been refreshed. If it has been refreshed, a synchronization refresh flag is set for internal use. After completing the output of 6 pulses in this cycle, the flag is cleared, and the system waits for the next cycle to recheck whether the synchronization time has been refreshed.

[0034] Pulse output is allowed when there is a synchronization refresh flag; otherwise, pulse output is prohibited in this cycle.

[0035] After the synchronization time is refreshed, the system starts checking whether data is received from the online control channel of the excitation regulating cabinet. If data is received, the control angle is refreshed according to the data; otherwise, the previous control angle is used.

[0036] Then it collects its own status data and starts sending data to the excitation control cabinet.

[0037] After data communication is completed, it checks whether excitation output is needed. If there is an excitation output flag, the output pulse is set according to the current pulse sequence number.

[0038] The high-frequency control method differs significantly from the previous method of refreshing the control angle once per cycle, such as... Figure 5 As shown.

[0039] Firstly, the interrupt time determined by the synchronous interrupt is independent of the first pair of pulses in the current cycle. The second pair of pulses can only be aligned according to the synchronous interrupt time after the first pair of trigger pulses has been output. This is because the delay setting for the first pair of pulses is set when the 6th pair of pulses is output in the previous cycle. When the control angle is less than 60°, the synchronous interrupt corresponding to the start of the new cycle has not yet occurred when the delay of the first pair of pulses is set. Furthermore, the delay of the first pair of pulses cannot be set directly during the synchronous interrupt. When the control angle is greater than 60°, pulse interrupts from the previous cycle will still refresh the control angle after the synchronous interrupt occurs, meaning the control angle at the time of the synchronous interrupt is not the latest.

[0040] Secondly, each pulse interrupt must complete one communication, and the 60° interrupt delay must be fine-tuned according to the change in the control angle. Because it is a 60° delay, the change in the control angle must not be less than -40° to prevent two pulse interruptions from being too close together.

[0041] Finally, since the delay interrupt of the first pair of pulses is not directly set by the synchronous interrupt, in order to ensure that the output stops when the synchronous signal is missing, a synchronous timing change flag is set in the synchronous interrupt, and the pulse interrupt determines whether to output a pulse based on this flag.

[0042] In the timed interrupt of the output trigger pulse, the power cabinet of this disclosure first checks whether it receives data from the excitation regulating cabinet control channel. If data is received, it refreshes the control angle according to the online control channel data, then sets the current pulse delay according to the trigger angle, and finally immediately sends its own data to the excitation regulating cabinet control channel.

[0043] The excitation regulating cabinet control channel of this disclosure detects power cabinet data in a 1-millisecond cycle task. After completing the first power cabinet data reception, it initiates the current data transmission to the power cabinets and starts a 2-millisecond delay communication cycle count. If all power cabinet data is received or the communication cycle delay count reaches 2 milliseconds, the current communication cycle ends, and it waits for the next power cabinet data reception.

[0044] This power cabinet detects whether the synchronization time has been refreshed before outputting the first pair of trigger pulses; if not, it stops outputting pulses.

[0045] The power cabinet disclosed herein sets the delay when outputting the first pair of pulses to be the delay corresponding to the current control angle plus 60° minus the time from the synchronization moment to the current moment. The delay when outputting other pulses is the delay corresponding to the sum of the deviation between the current control angle and the previous control angle plus 60°.

[0046] A high-frequency control system for an intelligent power cabinet. The settings are configured in the pulse interrupt service routine of the timer via the intelligent power cabinet, including: The system includes a synchronous interruption time recording unit, a synchronous refresh unit, a control angle refresh unit, a data transmission unit, and an excitation output unit. The synchronous interruption time recording unit is used to record the synchronous interruption time as the starting point of the current cycle. The synchronous refresh unit is used in the pulse interrupt service routine to first detect whether the synchronous time has been refreshed. If it has been refreshed, the synchronous refresh flag is set; otherwise, the output pulse for the current cycle is prohibited. The control angle refresh unit is used to detect whether data is received from the online control channel of the excitation regulating cabinet. If data is received, the control angle is refreshed according to the data; if no data is received, the previous control angle is used. The data transmission unit is used to collect its own status data and send the data to the excitation control cabinet; The excitation output unit is used to determine whether excitation output is needed after data communication is completed. If so, it sets and outputs a trigger pulse according to the current pulse sequence number.

[0047] 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 high-frequency control method for an intelligent power cabinet, characterized in that, The settings are configured in the pulse interrupt service routine of the timer via the intelligent power cabinet, including: Record the moment of the synchronous interrupt as the starting point of the current cycle in the synchronous interrupt; In the pulse interrupt service routine, first check if the synchronization time has been refreshed. If it has been refreshed, set the synchronization refresh flag; otherwise, prohibit the output of pulse in the current cycle. Check if data is received from the online control channel of the excitation regulating cabinet. If received, refresh the control angle according to the data. If not received, use the previous control angle. Collect its own status data and send the data to the excitation control cabinet; After data communication is completed, determine whether excitation output is needed. If so, set and output the trigger pulse according to the current pulse sequence number.

2. The high-frequency control method for an intelligent power cabinet according to claim 1, characterized in that, The synchronization interrupt time is recorded as the starting point of the current cycle, including: When the current phase is the synchronous phase of the drive trigger pulse, record the interrupt time; Set a synchronization time change flag, and use the interrupt time as the start point of the cycle to provide pulse interrupt alignment pulses.

3. The high-frequency control method for an intelligent power cabinet according to claim 1, characterized in that, The pulse interrupt uses a timer interrupt, triggering six communications and pulse outputs within each power frequency cycle; the number of communications per power frequency cycle is determined by the multiple of the limit control frequency and the power frequency.

4. The high-frequency control method for an intelligent power cabinet according to claim 3, characterized in that, Each pulse interruption completes a data communication with the excitation control cabinet and a control angle refresh.

5. The high-frequency control method for an intelligent power cabinet according to claim 3, characterized in that, After completing six pulse outputs in this cycle, clear the synchronization refresh flag.

6. The high-frequency control method for an intelligent power cabinet according to claim 3, characterized in that, The synchronous interrupt is used to align the trigger pulses, and the delay setting of the first pair of trigger pulses in this cycle is completed when the sixth pair of pulses is output in the previous cycle.

7. The high-frequency control method for an intelligent power cabinet according to claim 1, characterized in that, The method requires that the change in the control angle be no less than the preset angle to ensure that the time interval between two adjacent pulse interruptions meets the requirements.

8. A high-frequency control system for an intelligent power cabinet, characterized in that, The settings are configured in the pulse interrupt service routine of the timer via the intelligent power cabinet, including: The system includes a synchronous interruption time recording unit, a synchronous refresh unit, a control angle refresh unit, a data transmission unit, and an excitation output unit. The synchronous interruption time recording unit is used to record the synchronous interruption time as the starting point of the current cycle. The synchronous refresh unit is used in the pulse interrupt service routine to first detect whether the synchronous time has been refreshed. If it has been refreshed, the synchronous refresh flag is set; otherwise, the output pulse for the current cycle is prohibited. The control angle refresh unit is used to detect whether data is received from the online control channel of the excitation regulating cabinet. If data is received, the control angle is refreshed according to the data; if no data is received, the previous control angle is used. The data transmission unit is used to collect its own status data and send the data to the excitation control cabinet; The excitation output unit is used to determine whether excitation output is needed after data communication is completed. If so, it sets and outputs a trigger pulse according to the current pulse sequence number.

9. The high-frequency control system for an intelligent power cabinet according to claim 8, characterized in that, The synchronization interrupt time is recorded as the starting point of the current cycle, including: When the current phase is the synchronous phase of the drive trigger pulse, record the interrupt time; Set a synchronization time change flag, and use the interrupt time as the start point of the cycle to provide pulse interrupt alignment pulses.

10. The high-frequency control system for an intelligent power cabinet according to claim 8, characterized in that, The pulse interrupt uses a timer interrupt, triggering six communications and pulse outputs within each power frequency cycle; the number of communications per power frequency cycle is determined by the multiple of the limit control frequency and the power frequency.

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