Permanent Magnet Generator Controller Using Current Feedback
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Solution Overview
Problem
Permanent magnet generators face challenges in maintaining stable output voltage due to varying generator speed and load, requiring complex control systems that often rely on rotor position and voltage measurements.
Innovation Solution
A controller method that uses electrically controllable switches and data processing to regulate the generator phases by measuring current output, forming a current error, and deriving target voltage and phase angles without needing rotor position or voltage measurements, allowing for stable power factor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rotor position sensors and voltage measurement systems are added to achieve stable voltage control, then voltage stability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for rotor position sensors and voltage measurement systems by using an alternative control approach. The controller achieves voltage stability by measuring only generator current and using current-based feedback control, removing the disturbing components (sensors and measurement systems) while maintaining the essential control function.
Solution Approach 2:
The generator control system uses the generator's own current measurements to self-regulate voltage output without external sensors. The current measurement and control algorithm work together to inherently maintain voltage stability, allowing the system to serve itself without additional measurement infrastructure.
2Measurement precision
If rotor position sensors are installed to enable precise voltage control, then control precision is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent removes the requirement for rotor position sensors from the manufacturing process. By using current measurement and control algorithms that do not depend on position data, the system achieves precise control without the complex sensor installation and calibration steps, greatly simplifying manufacturing.
Solution Approach 2:
The patent replaces the mechanical/physical sensor-based position detection system with an electrical control system based on current measurements and mathematical algorithms. This substitution eliminates the need for physical sensors while maintaining or improving control precision through software-based solutions.
3Reliability
If multiple sensors and measurement systems are added for stable control, then reliability of control is improved, but device complexity and maintenance requirements increase
Solution Approach 1:
The patent extracts and removes multiple sensors and measurement systems from the control architecture, retaining only the essential current measurement. This reduction in components directly lowers device complexity and maintenance requirements while the control algorithm compensates to maintain reliability.
Solution Approach 2:
The patent applies local quality by focusing measurement and control efforts on the most critical parameter (generator current) rather than distributing sensors across multiple locations. This concentrated approach maintains control reliability by ensuring accurate measurement where it matters most while avoiding the complexity of multiple distributed sensors.
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 stable generator operation without the need for rotor position or voltage measurements, ensuring consistent output voltage and efficient power factor management, thus improving reliability and simplifying control systems.
Implementation Method 1
Rotation of the rotor causes the magnets to be moved towards and then away from the stator coils, held by the stator of the generator. The voltage generated in each stator coil is proportional to the rate of change of magnetic flux cutting the coil.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A generator controller for controlling a permanent magnet generator where each phase of the generator (20) is connectable to a DC link (30, 32) via electrically controllable switches (26, 28), the controller characterised by a data processor (42) adapted to receive a measurement of generator current output (Ia, Ib, Ic, Im) and a demand current (I*), and to form a current error between the demanded value and the measured generator current; derive a target voltage as a function of the current error; and form control signals for the electrically controllable switches as a function of the target voltage.