Synchronous Power-On/Off Control for Generator Phase Matching
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Solution Overview
Problem
Current synchronous power-on/off control methods fail to maintain seamless switching between electric power sources without instantaneous interruption, especially under varying conditions such as low temperatures, where phase differences do not change dynamically, leading to instability and prolonged synchronization times.
Innovation Solution
A method and controller that detect frequency and phase differences between power sources, using feedback control and proportional-integral control to maintain these within predetermined ranges, and adjust generator rotation speed through a toroidal continuously variable transmission and hydraulic servo system to ensure stable and rapid synchronization, even under conditions like low oil temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional synchronous power-on/off control is used, then switching without instantaneous interruption can occur under normal temperature conditions, but under low-temperature conditions the phase difference does not change dynamically and synchronization fails
Solution Approach 1:
The patent implements dynamic adjustment of the phase difference threshold range based on operating conditions. The control unit dynamically expands the threshold range when phase difference change rate decreases, allowing the system to adapt to low-temperature conditions where phase difference dynamics are reduced, thereby maintaining reliable synchronous switching across varying environmental conditions
Solution Approach 2:
The patent changes the parameter of phase difference threshold range dynamically. When the phase difference change rate falls below a threshold (indicating low-temperature or stagnant conditions), the control unit expands the acceptable phase difference range, allowing synchronization to proceed under conditions where strict phase matching would otherwise fail
2Measurement precision
If the phase difference threshold range is kept narrow for precise synchronization, then synchronization accuracy is improved, but the system becomes sensitive to condition changes and synchronization fails under low-temperature conditions
Solution Approach 1:
The patent makes the phase difference threshold range dynamic rather than fixed. The control unit continuously monitors the phase difference change rate and adjusts the threshold range accordingly - maintaining narrow ranges for precision during normal operation, and expanding the range when conditions indicate reduced dynamics (low temperature), thus balancing precision and reliability
Solution Approach 2:
The patent employs feedback control by continuously monitoring the phase difference change rate and using this information to adjust the phase difference threshold range. This feedback mechanism allows the system to detect when conditions are deteriorating (phase change stagnation) and automatically compensate by expanding the acceptable threshold range
3Ease of operation
If synchronous power-on/off fails under low-temperature conditions, then the system can recover, but it takes time to perform synchronous power-on/off again
Solution Approach 1:
The patent performs preliminary action by proactively detecting when the phase difference change rate decreases (indicating approaching low-temperature failure conditions) and preemptively expanding the phase difference threshold range. This prevents synchronization failure before it occurs, eliminating recovery time and ensuring continuous operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables continuous, stable synchronous power-on/off operations by maintaining phase differences at zero, expanding the acceptable range and reducing the impact of condition changes, thus ensuring seamless switching without instantaneous interruption.
Implementation Method 1
a tilt motion angle of a power roller included in the transmission device is adjusted by a hydraulic servo system
Data Source
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AI summary
A power-on/off command is output to a breaker for switching in a case where a frequency difference between a plurality of electric power supply sources is within a predetermined range and a phase difference between the plurality of electric power supply sources is within a predetermined range, in switching of electric power supply between the plurality of electric power supply sources. A least one of the plurality of electric power supply sources is an electric generator driven by a driving power source via a transmission device. It is determined whether or not the detected frequency difference is within the predetermined range, and whether or not the detected phase difference is within the predetermined range. A generator drive rotation speed of the transmission device is feedback controlled so that the frequency difference is maintained at a value within the predetermined range and the phase difference is maintained at a value within the predetermined range, in a case where it is determined that the detected frequency difference is within the predetermined range and the detected phase difference is within the predetermined range. At this time, a generator rotation speed command is calculated by adding to the rotation speed command of the transmission device an output value obtained by subjecting the detected phase difference to a proportional-integral-control. The generator drive rotation speed is feedback controlled based on the generator rotation speed command, and the power-on/off command is output to the breaker, in a case where it is determined that the detected frequency difference is within the predetermined range and the detected phase difference is within the predetermined range.