Variable Speed Generator Fuel Optimization via Inverter Frequency Control
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Solution Overview
Problem
Existing engine-driven electrical generators operate at a fixed speed, leading to suboptimal fuel efficiency and increased noise, as they are designed to produce power at a fixed frequency, which is not adaptable to varying loads, resulting in inefficient energy use and excessive noise.
Innovation Solution
A method to control the speed of an engine-driven electrical generator to optimize fuel consumption by varying the engine speed in response to load demands, while maintaining a constant frequency, using a Double Fed Induction Generator with an inverter system that adjusts the output voltage frequency to match the load, allowing the engine to operate at a lower speed, reducing noise and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the engine operates at a fixed predetermined speed to maintain constant frequency output, then the frequency stability is improved, but the fuel efficiency deteriorates under varying load conditions
Solution Approach 1:
The patent implements variable speed operation where the engine speed dynamically adjusts according to load conditions. The controller modifies the operating speed of the engine based on detected load levels, allowing the system to transition from fixed-speed operation to dynamic speed adjustment, thereby optimizing fuel efficiency while maintaining frequency stability through power electronic conversion.
Solution Approach 2:
The system changes the operating parameters of the engine by adjusting its speed according to load demands. Rather than maintaining a constant predetermined speed, the engine operates at variable speeds optimized for different load conditions, with the frequency stabilization achieved through the interaction of the generator and inverter system rather than fixed mechanical speed.
2Stability of the object's composition
If the engine operates at a fixed predetermined speed, then the frequency output is stable, but the noise level increases
Solution Approach 1:
The system dynamically adjusts engine speed based on actual load requirements rather than maintaining constant predetermined speed. This dynamic operation allows the engine to run at lower, quieter speeds when full power is not needed, while the frequency stability is maintained through the control system and power electronic conversion.
3Use of energy by moving object
If the engine speed is reduced to optimize fuel efficiency, then the fuel consumption is improved, but the output frequency deviates from the predetermined level
Solution Approach 1:
The patent introduces power electronic conversion equipment (inverter/rectifier system) as an intermediary between the variable-speed engine and the electrical load. This intermediary component enables frequency conversion, allowing the engine to operate at optimized variable speeds for fuel efficiency while the electronic converter maintains the output frequency at the predetermined level required by the load.
Solution Approach 2:
The system replaces the traditional mechanical frequency regulation method (maintaining fixed engine speed through mechanical governors) with an electronic control approach. The frequency stability is achieved through electronic power conversion and control rather than mechanical speed regulation, enabling the engine to operate at variable speeds optimized for fuel efficiency.
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 approach enhances fuel efficiency and reduces noise by allowing the generator to operate at lower speeds while maintaining constant frequency and voltage, optimizing energy use and minimizing environmental impact.
Implementation Method 1
The step of modifying the frequency of the output voltage includes the additional steps of calculating the difference between the frequency of the output voltage and the predetermined level and providing the difference as an adjustment frequency. The frequency of the output voltage is modified by the adjustment frequency.
Implementation Method 2
The inverter supplies power to the rotor windings at the adjustment frequency. The stator has a main winding and a quadrature winding, and the inverter includes a DC link. The sensing input of the inverter is operatively connected to the main winding and power for the DC link is operatively connected to the quadrature winding.
Data Source
Figure 1
AI summary
A method of controlling an engine-driven, electrical generator is provided. The generator generates an output voltage at a frequency with the engine running at an operating speed. The method includes the steps of connecting the generator to a load and varying the operating speed of the engine to optimize fuel consumption in response to the load. Thereafter, the frequency of the output voltage is modified to a predetermined level.