Excitation Synchronous Generator Control for Grid Stability
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Solution Overview
Problem
Wind power generation systems with permanent magnet or induction generators face inefficiencies due to power conversion losses and inability to maintain constant voltage and frequency when wind power varies, leading to reduced output quality.
Innovation Solution
A control method using motor servo control and excitation current control for an excitation synchronous generator, which adjusts rotation speed and phase to stabilize output power, incorporating a maximum power determining unit for optimal power tracking and feedback control to manage excitation current and voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If AC-to-DC converter and DC-to-AC converter are used for power conversion, then wind power can be transmitted to the utility grid, but power conversion efficiency deteriorates and equipment cost increases
Solution Approach 1:
The patent extracts and eliminates the AC-to-DC and DC-to-AC converter components from the system. By using a synchronous generator with excitation current control, the system directly converts mechanical energy from the wind turbine to electrical energy suitable for grid connection, removing the intermediate conversion stages that caused power losses and increased equipment cost.
Solution Approach 2:
The patent replaces the electrical conversion system (converters) with a directly controlled synchronous generation system. The excitation current control mechanism allows the synchronous generator to directly produce grid-compatible AC power, substituting the mechanical-electrical conversion path that previously required dual conversion stages.
2Device complexity
If induction generator is used, then power generation is simple, but voltage and frequency cannot be kept constant when wind power varies, reducing output power quality
Solution Approach 1:
The patent implements feedback control through excitation current regulation. The system continuously monitors the output voltage and frequency of the synchronous generator and adjusts the excitation current accordingly to maintain constant voltage and frequency despite variations in wind power input, ensuring high output power quality.
Solution Approach 2:
The patent employs dynamic excitation current control to adapt the generator's magnetic field strength in real-time. This dynamic adjustment allows the synchronous generator to maintain stable voltage and frequency output under varying operational conditions, overcoming the static limitations of induction generators.
3Reliability
If transmission mechanism rotation speed is limited, then generator safety is ensured, but maximum wind power cannot be utilized when wind power exceeds standard range
Solution Approach 1:
The patent implements dynamic speed control of the transmission mechanism through servo motor control. Instead of rigidly limiting rotation speed, the system dynamically adjusts the speed within safe operational boundaries, allowing the generator to operate at optimal speeds for maximum power capture while preventing speeds that would compromise safety.
Solution Approach 2:
The patent changes the operational parameters of the transmission mechanism by implementing variable speed control. The system adjusts rotation speed as a controllable parameter based on real-time wind conditions, enabling the generator to capture maximum power across a wider range of wind speeds while maintaining safety through controlled parameter limits.
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 method ensures stable power output with constant frequency and phase, maximizing power transfer to the utility grid while minimizing servo motor power consumption, even with varying wind power conditions.
Implementation Method 1
an excitation synchronous generator; a transmission mechanism configured to use the wind turbine rotor to drive the excitation synchronous generator
Implementation Method 2
a motor configured to drive the transmission mechanism
Data Source
AI summary
A wind power excitation synchronous generation system having a maximum power determining unit and a control method thereof are disclosed. In this control method, dual input shafts and a single output shaft of a gear transmission mechanism are used, and two kinds of inputted power, such as wind power and servo motor control power, are integrated, so as to allow the output shaft to drive an excitation synchronous generator to generate electric power. In this system, a rotation speed and a phase of a servo motor are controlled, so as to allow the excitation synchronous generator to output the electric power with a frequency and a phase identical to the utility grid.