Motor Driving Device Power Failure Protection
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Solution Overview
Problem
Existing motor driving devices face challenges in maintaining normal operation during power failures, leading to potential breakage and deformation of motors and associated equipment due to increased volume and cost of electric storage devices required for energy storage.
Innovation Solution
A motor driving device with a rectifier, inverter, power failure detecting unit, electric storage device, charging unit with voltage boosting function, discharging unit, and control unit that manages energy storage and discharge to ensure continuous operation during power failures, along with a regenerated electric power consuming unit to manage voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric storage device is increased in capacity to supply sufficient energy for protecting operation during power failure, then the reliability of continuous operation is improved, but the volume and cost of the motor driving device increase
Solution Approach 1:
The patent charges the electric storage device in advance during normal operation before power failure occurs. The control unit activates the charging unit to store energy in the electric storage device when power is available, so that sufficient energy is already stored to support protecting operation when power failure occurs, eliminating the need for oversized storage capacity.
Solution Approach 2:
The patent dynamically changes the charging voltage parameter by using a charging unit that can output a charging voltage different from the direct current link voltage. This allows efficient charging of the electric storage device with optimized voltage parameters, reducing the required storage capacity while maintaining sufficient energy for protecting operation.
2Reliability
If the electric storage device is increased in capacity to supply sufficient energy for protecting operation, then the ability to prevent breakage and deformation is improved, but the cost of the motor driving device increases
Solution Approach 1:
The system performs preliminary charging of the electric storage device during normal operation, ensuring sufficient energy is stored before power failure. This allows the use of a smaller, more cost-effective electric storage device while still providing adequate energy for protecting operation and preventing breakage or deformation of the motor and tool.
Solution Approach 2:
The charging unit operates continuously or periodically during normal operation to maintain energy storage in the electric storage device. This continuous energy accumulation ensures that the motor can perform protecting operation without interruption or damage, while keeping the storage device size and cost reasonable.
3Use of energy by moving object
If a voltage boosting function is added to the charging unit to charge the electric storage device to a voltage higher than the direct current link voltage, then the energy storage efficiency is improved, but the device complexity increases
Solution Approach 1:
The charging unit incorporates a voltage boosting function that changes the voltage parameter during charging operation. By outputting a charging voltage higher than the direct current link voltage, the system improves energy transfer efficiency and reduces charging time, while the control unit manages the voltage transformation to keep the overall system design manageable.
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 solution enables a compact and low-cost motor driving device that can supply energy for protecting operations during power failures, minimizing damage and deformation, while optimizing storage capacity and device size through efficient energy management.
Implementation Method 1
a rectifier that converts alternating current power supplied from an alternating current side into direct current power
Implementation Method 2
an inverter that is connected to a direct current link on a direct current side of the rectifier and that mutually transforms electric power between direct current power at the direct current link and alternating current power that is driving electric power for a motor
Implementation Method 3
an electric storage device that is connected to the direct current link and that includes a capacity for storing direct current power
Implementation Method 4
a charging unit that has a voltage boosting function of charging the electric storage device to a voltage higher than a direct current voltage at the direct current link
Implementation Method 5
a discharging unit for making a short-circuit between the electric storage device and the direct current link to cause direct current power stored in the electric storage device to be discharged to the direct current link
Data Source
AI summary
A motor driving device includes a rectifier, an inverter connected to a DC link on a DC side of the rectifier, a power failure detecting unit for detecting a power failure on the alternating side of the rectifier, an electric storage device connected to the DC link, a charging unit that possesses a voltage boosting function of charging the electric storage device by direct current power at the DC link, a discharging unit that causes direct current power stored in the electric storage device to be discharged to the DC link, and a control unit that causes the charging unit to operate when the power failure detecting unit does not detect a power failure, or before start of motor drive, and causes the discharging unit and the inverter to operate when the power failure detecting unit detects a power failure.