ISVF Generator Excitation Control for Stable Output Voltage
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Solution Overview
Problem
ISVF generators present unique voltage regulation challenges due to their frequency and phase angle dependencies, which traditional power regulation methods fail to address effectively.
Innovation Solution
A method and system utilizing a generator control unit with a frequency-to-voltage converter, PID controller, and excitation source controller to generate excitation voltage and frequency control signals, ensuring constant voltage magnitude and frequency of the output voltage across varying shaft speeds and load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If typical power regulation methods are used, then the system is simple to operate, but voltage regulation precision deteriorates because frequency and phase angle dependencies of ISVF generators are not considered
Solution Approach 1:
The patent transforms the regulation approach by changing from traditional voltage-only control to a comprehensive control method that considers frequency and phase angle parameters. The frequency-to-voltage converter converts frequency deviations into voltage signals that are processed by the PID controller, enabling dynamic adjustment of excitation voltage based on frequency and phase angle relationships. This parameter transformation resolves the contradiction by improving voltage regulation precision through multi-parameter consideration while maintaining manageable system complexity.
Solution Approach 2:
The patent replaces traditional mechanical voltage regulation mechanisms with an electronic control system. The frequency-to-voltage converter, PID controller, and excitation source controller form an electronic regulation system that dynamically adjusts excitation voltage based on frequency and phase angle measurements. This substitution enables more precise control of voltage magnitude and frequency while providing adaptability to varying operating conditions, resolving the contradiction between precision and complexity.
2Reliability
If excitation voltage is increased to maintain constant output voltage, then voltage regulation improves, but the system becomes more sensitive to frequency and phase angle variations
Solution Approach 1:
The patent implements a feedback control mechanism where the PID controller continuously monitors the difference between reference voltage and measured output voltage, and adjusts excitation voltage accordingly. The frequency-to-voltage converter also provides feedback by converting frequency deviations into corrective voltage signals. This feedback system maintains voltage stability while automatically compensating for frequency and phase angle variations, reducing the difficulty of control by making the system self-regulating.
Solution Approach 2:
The patent applies preliminary action by using the frequency-to-voltage converter to generate excitation voltage reference components based on shaft frequency before voltage deviations occur. The lookup table provides pre-calibrated excitation voltage references that correspond to different shaft frequency values, enabling proactive compensation for frequency variations. This preliminary control action maintains voltage stability while simplifying the detection and measurement of frequency and phase angle relationships.
3Adaptability or versatility
If traditional regulation methods are used, then the device complexity is low, but the adaptability to varying shaft speeds and load conditions deteriorates
Solution Approach 1:
The patent introduces dynamics by making the excitation voltage control adaptive to varying shaft speeds and load conditions. The frequency-to-voltage converter dynamically adjusts excitation voltage reference based on real-time shaft frequency measurements. The PID controller dynamically modifies excitation voltage in response to voltage deviations caused by load changes. This dynamic control approach enables the system to adapt to varying operating conditions while maintaining manageable complexity through systematic control architecture.
Solution Approach 2:
The patent achieves universality by designing a control system that handles multiple functions: voltage regulation, frequency control, and phase angle compensation. The frequency-to-voltage converter serves both frequency measurement and excitation control functions. The PID controller manages both voltage magnitude and frequency regulation. This multi-functional approach improves adaptability to varying shaft speeds and load conditions while avoiding the complexity of separate dedicated systems for each function.
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
The solution effectively regulates the voltage of ISVF generator-based power systems, maintaining constant output voltage magnitude and frequency despite changes in shaft speed and load disturbances, thus ensuring reliable operation within defined limits.
Implementation Method 1
a frequency-to-voltage converter configured to generate a first excitation voltage reference component based on a shaft frequency of an ISVF generator
Implementation Method 2
a proportional-integral-derivative controller (PID) configured to generate a second excitation voltage reference component based on a difference between a reference voltage and a measured output voltage
Implementation Method 3
an excitation source controller configured to generate an excitation voltage control signal based on a combination of the first excitation voltage reference component and the second excitation voltage reference component, the excitation voltage control signal usable to control a voltage magnitude of an excitation signal
Implementation Method 4
an output voltage amplitude of an ISVF generator may be based on a combination of a first magnetic flux generated by rotation of a main field winding and a second magnetic flux generated by an excitation signal applied to the main field winding
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A system may include an independent speed variable frequency (ISVF) generator and an excitation source configured to provide an excitation signal to rotor field windings of the ISVF generator to produce a rotating magnetic flux that is independent of a shaft speed of the ISVF generator. The system may include a bus configured to receive an output voltage of the ISVF generator. A generator control unit may be configured to generate a first excitation voltage reference component based on a shaft frequency of the ISVF generator, generate a second excitation voltage reference component based on a difference between a reference voltage and a measured output voltage of the ISVF generator, and generate an excitation voltage control signal based on a combination of the first excitation voltage reference component and the second excitation voltage reference component, the excitation voltage control signal usable to control a voltage magnitude of the excitation signal.