Method for controlling inverter and system
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Solution Overview
Problem
Inverter systems controlling multiple motors face inefficiencies in energy management, particularly when load characteristics change, leading to repeated sleep and wake operations and potential abnormal modes due to inappropriate sleep and wake-up level settings.
Innovation Solution
A method for controlling an inverter that enters a sleep mode based on actual load changes, where the motor operates normally if load feedback changes with frequency variations, and transitions to sleep mode only when load is below the sleep level after a delay, preventing errors from load bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the inverter enters sleep mode when load is below sleep level, then energy consumption is reduced, but repeated sleep and wake operations occur when load characteristics change, causing abnormal modes
Solution Approach 1:
The patent applies dynamics by making the sleep mode entry condition adaptive rather than fixed. The controller dynamically adjusts the sleep determination based on the relationship between operating frequency and load feedback. When load feedback changes significantly with frequency variations, the system determines there is actual load and prevents sleep mode entry, thereby avoiding repeated wake-sleep cycles and maintaining operational stability while still enabling energy savings during genuine idle periods.
2Device complexity
If the inverter uses fixed sleep and wake-up level settings, then control is simple, but errors occur due to load bands and sensitive load changes
Solution Approach 1:
The patent implements feedback by continuously monitoring the relationship between operating frequency changes and load feedback changes. The controller uses this feedback to dynamically determine whether the load is actual or virtual. When load feedback changes significantly in response to frequency variations, the system identifies actual load conditions and adjusts sleep determination accordingly. This feedback mechanism improves load detection accuracy without significantly increasing control complexity, as it builds upon existing frequency and load monitoring capabilities.
Data Source
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AI summary
A method for controlling an inverter in a system including a load, a motor for driving the load, and an inverter for operating the motor comprises when a load amount of the load is reduced to below a sleep level, checking whether a time corresponding to a sleep delay has lapsed; when the load amount of the load is still below the sleep level even after the sleep delay, varying an operating frequency of the motor, and if there is no change in a feedback from the load in response to the variation in the operating frequency, controlling the inverter to enter a sleep mode.