Generator Start Control to Pass Resonance With Limited Battery Power
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Solution Overview
Problem
Existing power generation systems in vehicles face challenges in rapidly increasing the rotation speed of the electrical generator beyond the resonance frequency band due to insufficient battery power, leading to prolonged oscillation and vibration when starting the system.
Innovation Solution
A method and device that control the starting of the power generation system by implementing a cryogenic start mode, which includes a filtering process to reduce resonance frequency components, allowing the electrical generator to rapidly increase its speed beyond the resonance frequency band even with limited battery power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the electrical generator is driven by electric power from the battery to rapidly increase rotation speed beyond resonance frequency band, then oscillation and vibration are reduced, but electric power consumption increases beyond available battery capacity
Solution Approach 1:
The patent divides the rotation speed increase process into two distinct phases: a first rotation speed control phase that operates within the resonance frequency band, and a second rotation speed control phase that operates beyond the resonance frequency band. This segmentation allows the system to achieve rapid speed increase while managing power consumption in stages, with the first phase consuming less power and the second phase providing the necessary power boost to exceed resonance frequencies and reduce oscillation.
Solution Approach 2:
The patent dynamically switches between different control modes based on the current rotation speed relative to the resonance frequency band. The control device transitions from first rotation speed control (within resonance band) to second rotation speed control (beyond resonance band) when the rotation speed exceeds the resonance frequency. This dynamic adaptation allows optimal power usage at each stage while ultimately achieving the goal of reducing oscillation by exceeding the resonance frequency band.
2Measurement precision
If rotation speed control matches electrical generator speed with target speed, then control precision is improved, but fluctuation in rotation speed is promoted and time in resonance frequency band increases
Solution Approach 1:
The patent employs dynamic control by switching between two rotation speed control modes. The first mode provides precise control within the resonance frequency band, while the second mode enables rapid acceleration beyond the resonance band. This dynamic switching resolves the contradiction by allowing precise control when necessary (first mode) while minimizing time in the resonance band through the second mode's rapid acceleration capability.
Solution Approach 2:
The second rotation speed control is designed to rapidly accelerate the electrical generator beyond the resonance frequency band, effectively skipping through the problematic resonance region. This rushing through approach minimizes the time spent in the resonance frequency band, reducing oscillation duration while still maintaining control precision through the structured two-phase control strategy.
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
The method effectively reduces oscillation and vibration by rapidly increasing the electrical generator's rotation speed, ensuring efficient and stable power generation system startup even in low-temperature conditions.
Implementation Method 1
the electrical generator (15) is driven by electric power supplied from a battery (11) to rotate the engine (14) idly (so-called motoring)
Implementation Method 2
a power transmission mechanism (16) that transmits power between the engine (14) and the electrical generator (15)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6(B)
AI summary
This is a method for controlling starting of a power generation system including an internal combustion engine as a power source, an electrical generator, and a power transmission mechanism that transmits power between the internal combustion engine and the electrical generator, the method executes a rotation speed control of driving the electrical generator by using electric power supplied from a battery, and matching a rotation speed of the electrical generator with a target rotation speed at the time of starting the power generation system. According to the method, output possible electric power of the battery is acquired, and the rotation speed of the electrical generator is acquired. A filtering process of reducing a component of a resonance frequency band of a spring-mass system including the internal combustion engine, the electrical generator, and the power transmission mechanism is executed on the rotation speed of the electrical generator. Further, an upper limit torque that is an upper limit value of a torque of the electrical generator is calculated based on the filtered rotation speed of the electrical generator and the output possible electric power of the battery. In addition, the rotation speed control is executed under a limitation of the upper limit torque.