Motor Control Device Optimizing Discharge Timing for Energy Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In motor control devices, energy stored in electric storage devices is inefficiently used during power failures due to immediate discharge into the DC link, leading to voltage fluctuations and wasteful consumption by resistance discharge devices, which can result in insufficient energy for protecting operations and increased costs and volume of storage devices.
Innovation Solution
A motor control device with a power failure detecting unit, voltage detecting unit, electric storage device, charging unit with boosting function, discharging unit, resistance discharge device, and discharging operation determining unit that controls the timing of discharging and resistance discharging operations to optimize energy use and prevent wasteful consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric storage device immediately discharges stored energy into the DC link upon power failure detection, then the protecting operation can start quickly, but the energy is wastefully consumed by the resistance discharge device due to voltage fluctuations
Solution Approach 1:
The control device determines the optimal discharge timing in advance by monitoring DC link voltage before power failure occurs. When voltage drops to a predetermined level, the control device prepares to discharge stored energy at the most efficient moment, preventing wasteful consumption by the resistance discharge device while ensuring quick protecting operation启动
Solution Approach 2:
The control device continuously monitors DC link voltage and uses this feedback to determine the precise timing for discharging stored energy. By detecting voltage fluctuations and comparing them against predetermined thresholds, the system optimizes discharge timing to minimize energy loss to the resistance discharge device while maintaining rapid response capability
2Reliability
If the electric storage device has larger capacity to ensure sufficient energy for protecting operation, then energy shortage is prevented, but the cost and volume of the storage device increase
Solution Approach 1:
The control device changes the operational parameters of energy discharge by optimizing timing based on DC link voltage levels. By discharging at the most efficient moment rather than immediately or continuously, the system maximizes the effective use of stored energy, allowing smaller storage devices to provide sufficient energy for protecting operations
3Stability of the object's composition
If the resistance discharge device operates continuously to consume DC power, then voltage stability is maintained, but energy efficiency deteriorates
Solution Approach 1:
Instead of continuous operation, the resistance discharge device is activated periodically and selectively based on real-time DC link voltage conditions. The control device determines optimal discharge moments when voltage drops to predetermined levels, creating a periodic rather than continuous operation pattern that maintains voltage stability while improving energy 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
Efficient use of stored energy for protecting operations during power failures, preventing wasteful consumption by the resistance discharge device, and ensuring reliable performance without energy shortages or excessive device costs.
Implementation Method 1
an electric storage device (17) connected to the DC link (13) via the charging unit (15) and the discharging unit (16), and storing DC power
Implementation Method 2
a resistance discharge device (19) connected to the DC link (13), and consuming DC power of the DC link (13) by resistance discharge
Data Source
AI summary
A motor control device includes a rectifier, an inverter connected to the rectifier via the DC link, a power failure detecting unit detecting power failure, a voltage detecting unit detecting a DC voltage at the DC link, an electric storage unit storing DC power, a charging unit that can make charging by boosting to a voltage higher than the DC voltage, a discharging unit discharging DC power, a resistance discharge device that performs resistance discharging of DC power at the DC link when the DC voltage after power failure is equal to or higher than a predetermined start level and that does not perform resistance discharging when the DC voltage is equal to or lower than a predetermined stop level, and a discharging operation determining unit operating the discharging unit when the DC voltage at the DC link after power failure is equal to or lower than a predetermined threshold.