Hybrid Crane Power Control for Torque Fluctuation Stability
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Solution Overview
Problem
Traditional hybrid-power control methods for cranes fail to address the significant torque and rotation speed fluctuations during operations, leading to lifting vibrations and inefficient energy use, as they are not tailored for the specific demands of crane operations.
Innovation Solution
A hybrid-power control method that integrates torque and rotation speed control of the engine and electric motor, using a vehicle body controller to adjust the oil pump displacement, pressure sensor feedback, and battery power management to optimize engine operation within an economic interval, with the electric motor compensating for torque fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electric motor continuously adjusts its output torque according to engine output to ensure optimal engine operation, then the engine operates within an optimal economic interval, but the output torque of the electric motor fluctuates significantly causing lifting vibrations
Solution Approach 1:
The control system implements feedback control by continuously monitoring the actual torque requirements of the crane operation and comparing them with the engine's slow response characteristics. The electric motor's output torque is adjusted based on real-time feedback from torque sensors and control signals, allowing it to compensate for the engine's response lag and maintain stable crane operation while keeping the engine in its optimal economic operating interval.
Solution Approach 2:
The electric motor serves as an intermediary between the engine and the crane load. It absorbs the torque fluctuations and response delays of the engine, providing smooth torque delivery to the crane operation. This intermediary role allows the engine to operate steadily in its optimal efficiency range while the electric motor handles the rapid torque adjustments needed for stable crane operation.
2Stability of the object's composition
If the electric motor operates in power generation mode to handle torque fluctuations, then the engine torque adjustment becomes limited, but the crane operation stability improves
Solution Approach 1:
The system dynamically switches the electric motor between motor mode and power generation mode based on real-time operating conditions. When the engine torque exceeds the required torque, the electric motor operates in power generation mode to charge the battery. When the engine torque is insufficient, the electric motor switches to motor mode to supplement the torque. This dynamic operation expands the overall torque adjustment range while maintaining crane operation stability.
Solution Approach 2:
The control system changes the operating parameters of the electric motor dynamically, adjusting its output torque and operating mode (motor or generator) based on the crane's load requirements and the engine's operating state. This parameter adjustment allows the system to maintain stability while adapting to various operating conditions and expanding the effective torque range.
3Device complexity
If traditional hybrid-power control methods are used designed for commercial vehicles, then the control system is simple, but the torque fluctuations are not addressed and the battery pack service life is shortened
Solution Approach 1:
The control system performs preliminary action by predicting the torque requirements of the crane operation based on the handle opening degree and load information. It proactively adjusts the engine and electric motor torque outputs before significant torque fluctuations occur, rather than merely reacting to them. This predictive control reduces frequent and severe battery charging-discharging cycles, thereby extending battery pack service life.
Solution Approach 2:
The system implements feedback control by continuously monitoring battery state of charge, torque requirements, and engine operating conditions. Based on this feedback, it optimizes the charging and discharging cycles of the battery pack, avoiding excessive and frequent charge-discharge operations that would shorten battery life, while still maintaining effective torque fluctuation damping.
Data Source
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AI summary
The present invention relates to a hybrid-power control method and system, and a crane. The control method comprises: reading an opening-degree signal of an operation handle, and calculating the displacement of an oil pump, which displacement is required by an operation; reading information of a pressure sensor at an oil outlet of the oil pump to obtain the pressure of a hydraulic system, and by means of the displacement of the oil pump, calculating a torque required by the operation of a crane; reading an opening-degree signal of an accelerator, and calculating a rotation speed required by the operation, so as to obtain a target rotation speed of an engine and a target rotation speed of an electric motor; reading information of the electric quantity and charging and discharging operation power of a power battery, and outputting charging and discharging power requirements of the power battery according to electric balance requirements of a vehicle; and by means of integrating the information, calculating an optimal torque actually emitted by the engine, and adjusting the engine to operate within an optimal economic interval. The hybrid-power control method and system, and the crane of the present invention can effectively improve the operation stability and economical efficiency of a hybrid power system. Products that balance stability, economical efficiency and environmental protection requirements can be created for crane users.