Synchronous Generator Exciter Voltage Control for Efficient Startup
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Solution Overview
Problem
Synchronous generators face challenges in starting up and synchronizing with motors efficiently due to the need for precise alignment of magnetic poles and the use of power electronics, pony motors, and induction rotor devices, which increase mass and decrease efficiency.
Innovation Solution
A system with an exciter and controller that generates a variable field current for a synchronous generator, using a waveform with AC and DC components in the exciter voltage, which is adjusted based on rotational speed to control the magnetic field and electric power output, enabling synchronization without additional power electronics or induction rotor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If power electronics, pony motors, and induction rotor devices are added to enable synchronous generator startup, then the generator can start up and synchronize with motors, but the mass of the system increases and efficiency decreases
Solution Approach 1:
The patent removes the need for external power electronics, pony motors, and induction rotor devices by extracting the startup functionality into the generator's own excitation system. The exciter provides controlled excitation voltage during startup, enabling the synchronous generator to self-start without additional heavy components.
Solution Approach 2:
The excitation system is designed to perform multiple functions: it provides field excitation during normal operation and serves as the startup mechanism during initialization. This multi-functionality eliminates the need for separate pony motors and power electronics, reducing system mass while maintaining startup capability.
2Ease of operation
If power electronics, pony motors, and induction rotor devices are added to enable synchronous generator startup, then the generator can start up and synchronize with motors, but efficiency decreases
Solution Approach 1:
The patent removes energy-lossy power electronics and auxiliary motors by extracting the startup function into the excitation system. The exciter delivers controlled voltage directly to the field winding, eliminating conversion losses associated with power electronics and the mechanical losses of pony motors.
Solution Approach 2:
The patent replaces mechanical startup methods (pony motors) with an electrical excitation-based startup mechanism. The exciter provides controlled electrical excitation that enables the generator to build up voltage and synchronize electrically, replacing mechanical drive methods with a more efficient electrical process.
3Reliability
If precise alignment of magnetic poles is required for synchronous generator startup, then synchronization with motors can be achieved, but the complexity of the startup process increases
Solution Approach 1:
The exciter provides preliminary controlled excitation to the field winding before the generator reaches operating speed. This preliminary action establishes the magnetic field in advance, enabling smooth synchronization without requiring complex real-time alignment adjustments during startup.
Solution Approach 2:
The excitation system dynamically adjusts the excitation voltage during startup based on the generator's rotational speed and load conditions. This dynamic control enables the system to adapt to changing conditions automatically, simplifying the startup process while maintaining precise synchronization through continuous adjustment rather than fixed alignment procedures.
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
Enables efficient synchronization of synchronous generators with motors without increasing mass or decreasing efficiency, allowing for smooth startup and operation across a range of rotational speeds.
Implementation Method 1
an exciter configured to generate a variable field current for a synchronous generator... control the magnetic field and electric power output
Implementation Method 2
synchronous generator configured to output variable electric power in accordance with the variable field current
Data Source
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AI summary
A system includes an exciter configured to operate with a synchronous generator. The exciter may be mechanically coupled and rotatable with the synchronous generator, or the exciter may be independently rotatable. The exciter is configured to output a field current for exciting the synchronous generator to produce a voltage and a current at an output of the synchronous generator. The synchronous generator may be synchronized with loads during a time when the synchronous generator is at substantially zero speed and the loads, such as motors, are at zero speed. A controller included in the system is configured to control output of the field current by the exciter with an exciter voltage. The controller may control the exciter voltage to selective include an AC component and DC component in accordance with a rotational speed of the exciter.