Variable Speed Drive Control for Motor Energy Efficiency
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Solution Overview
Problem
Conventional drive systems in crushers and similar electrical apparatuses operate with a large capacity motor at a low load ratio, leading to inefficient energy use due to constant torque operation, as they are rarely at maximum torque and often have a margin, making energy-saving operations insufficient.
Innovation Solution
A drive control device that detects physical amounts such as torque and output power, determines the rotational frequency relative to a base frequency, and adjusts the rotational frequency of the shaft based on threshold values to optimize energy use by varying the load characteristics, allowing for a more efficient use of a smaller capacity motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large capacity motor is used to ensure maximum torque capability, then the motor can handle peak load demands, but the motor operates at low load ratio during normal operation leading to energy inefficiency
Solution Approach 1:
The patent applies dynamics by making the motor speed variable rather than fixed. The control device dynamically adjusts the rotational speed of the motor based on real-time detection of load torque, allowing the system to operate efficiently across varying load conditions while maintaining the capability to handle peak loads when necessary.
Solution Approach 2:
The patent changes the operational parameters by adjusting motor speed based on load conditions. The control device detects physical quantities related to load torque and modifies the motor's rotational frequency accordingly, enabling the motor to operate at optimal efficiency points while still providing maximum torque capability when required.
2Reliability
If the motor operates with constant torque characteristic to ensure maximum torque availability, then the motor can handle sudden load increases, but the motor cannot achieve sufficient energy-saving operation during normal low-load conditions
Solution Approach 1:
The system transitions from static constant torque operation to dynamic torque control. The control device continuously monitors load conditions and adjusts motor speed dynamically, allowing the motor to operate with variable torque characteristics that match actual demand, thereby reducing energy waste during normal operation while maintaining torque availability when needed.
Solution Approach 2:
The patent implements feedback control by detecting physical quantities related to load torque and using this information to adjust motor speed. This closed-loop control enables the motor to respond to actual load conditions, maintaining necessary torque availability while avoiding energy waste by not operating at maximum torque capability when full torque is not required.
3Adaptability or versatility
If the motor is designed with considerable margin to handle load variations, then the motor can accommodate unexpected load increases, but the motor operates far from optimal efficiency point during usual operation
Solution Approach 1:
The patent applies dynamics by enabling the motor to adapt its operating speed to match actual load requirements. The control device detects load conditions and dynamically adjusts motor speed, allowing the system to maintain adaptability to load variations while operating near optimal efficiency points during usual operation, rather than running a margin-designed motor at consistently low efficiency.
4Use of energy by moving object
If a smaller capacity motor is used to reduce energy consumption, then energy efficiency improves, but the motor may not have sufficient capacity to handle peak load demands
Solution Approach 1:
The patent resolves this contradiction by making motor speed variable. A smaller capacity motor can be used because the control device dynamically adjusts speed based on load detection, allowing the motor to operate efficiently during normal conditions while still providing sufficient power for peak loads by increasing speed when load torque requires it.
Solution Approach 2:
The patent changes the operational parameters by allowing motor speed to vary based on detected load conditions. This enables a smaller capacity motor to replace a larger one, as the motor operates at optimal efficiency points during normal operation but can increase speed to handle peak load demands when necessary.
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
This approach enables the use of a smaller capacity motor while maintaining processing capacity, reducing energy consumption and preventing overload by dynamically adjusting the rotational frequency based on load conditions, thus optimizing energy use and preventing inefficiencies.
Implementation Method 1
an inverter for converting a frequency of an AC power supply
Data Source
AI summary
A drive control device is provided with a physical amount detection unit which detects the physical amount pertaining to the output of a motor, a rotational frequency determination unit for determining whether the rotational frequency of the motor is equal to or greater than a base rotational frequency, a threshold value selection unit for selecting a threshold value for the physical amount in accordance with the determination result of the rotational frequency determination unit, and a rotational frequency control unit for controlling the rotational frequency of a rotating shaft in accordance with the magnitude relationship between the detected physical amount and the selected threshold value.