Off-grid Generator Vector Control for Stable Output
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Off-grid generator sets face inefficiencies in fuel consumption and noise generation when operating at reduced loads, and they struggle to maintain constant output voltage and frequency, which is essential for modern electrical equipment.
Innovation Solution
An off-grid power generating apparatus with a stator having a single phase winding and a rotor with symmetric phase windings, coupled with an excitation control device that modulates engine speed and excitation current to maintain constant output voltage and frequency, utilizing sensors and calculating elements to adjust the rotation speed and magnetic field accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine operating speed is fixed to maintain constant output frequency, then the output frequency stability is improved, but the fuel efficiency deteriorates and noise increases when the electrical load is less than the rated load
Solution Approach 1:
The patent applies dynamics by making the engine operating speed variable rather than fixed. The control system dynamically adjusts the engine speed based on the actual electrical load conditions, allowing the generator to operate efficiently at partial loads while maintaining stable output frequency through closed-loop control of the excitation system and frequency regulation mechanisms.
Solution Approach 2:
The patent changes the operating parameters by allowing engine speed to vary within a range while using excitation control and frequency regulation to maintain stable output. The control system adjusts multiple parameters including excitation current, engine speed, and field winding current to achieve both fuel efficiency and frequency stability simultaneously.
2Reliability
If the engine operating speed is fixed to maintain constant output frequency, then the output frequency stability is improved, but the noise generation increases when the electrical load is less than the rated load
Solution Approach 1:
The control system dynamically adjusts engine speed based on load conditions, preventing the engine from operating at high speeds when full power is not required. This dynamic speed adjustment reduces mechanical noise and vibration while the excitation control system maintains stable output frequency through electronic regulation rather than mechanical speed constancy.
3Reliability
If a conventional generator structure with multiple phase windings in the stator is used, then the output voltage stability is improved, but the apparatus weight and cost increase
Solution Approach 1:
The patent extracts the multiple phase windings from the stator and relocates them to the rotor, leaving the stator with a single phase winding. This structural reconfiguration reduces the amount of copper and magnetic material in the stator, thereby reducing weight and cost, while the rotor carries the complex multi-phase winding structure necessary for stable voltage generation.
Solution Approach 2:
The patent inverts the conventional generator structure by placing the multi-phase windings on the rotor instead of the stator. This inversion allows the stator to be simpler and lighter, while the rotor performs the function of generating the rotating magnetic field with multiple phases, achieving both weight reduction and voltage stability.
4Reliability
If a conventional generator structure with multiple phase windings in the stator is used, then the output voltage stability is improved, but the manufacturing cost increases
Solution Approach 1:
By extracting the complex multi-phase windings from the stator and placing them on the rotor, the patent reduces the manufacturing complexity and material cost of the stator assembly. The rotor, which requires multi-phase windings for stable voltage generation, bears the manufacturing burden, simplifying overall production and reducing costs.
Solution Approach 2:
The structural inversion of placing multi-phase windings on the rotor instead of the stator simplifies stator manufacturing and reduces material costs, while maintaining voltage stability through the rotor's field winding configuration and control system.
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 solution optimizes fuel consumption, reduces noise, and ensures stable output voltage and frequency, enabling efficient power generation for a variety of electrical loads, including household appliances, while keeping the control system simple and cost-effective.
Implementation Method 1
a rotor with a plurality of symmetric phase windings... configured to generate a rotating magnetic field... a stator with a single phase winding configured to generate an induced voltage
Data Source
AI summary
A power generating apparatus and vector control method thereof are provided. The apparatus includes a rotor with plurality of symmetric phase windings, a stator with a single phase winding, sensors and an excitation control device. Current sensors on the stator side and on the rotor side are configured to measure the amplitudes of the load current and the phase current of the rotor respectively. A position sensor is configured to measure the angle of the rotor. The excitation control device is configured to regulate the engine speed responsive to load power. The excitation control device also generates a modulating signal in accordance with the target voltage vector of the rotor and the slip angle and regulates the excitation current in the phase windings of the stator with the modulating signal.