Reduce operation noise and energy cost with torque current control and torque forward compensation
Noise in mechanical systems often arises from mechanical vibration due to an unbalance load. Such unwanted torque spikes arise from load-torque ripples on the motor shaft, and delays in motor-winding current commutation.
By Control Engineering Staff
Austin, TX —Noise in mechanical systems often arises from mechanical vibration due to an unbalance load. Such unwanted torque spikes arise from load-torque ripples on the motor shaft, and delays in motor-winding current commutation. Charlie Wu, senior. system and application engineer in the Microcontroller Division at Freescale Semiconductor suggests that the company’s digital signal controllers can be used to eliminate audio-frequency instabilities in mechatronic systems caused by torque ripple.
“Most motor control systems can be implemented by an 8-bit microcontroller (MCU),” Wu says, “but performance is often poor because of lack of current feedback loop.”
“Without a current control loop plus torque forward compensation, acoustic noises caused by torque ripple cannot easily be eliminated,” Wu continues. “It is difficult to add a current control loop into control system based on an 8-bit MCU because the processor cannot perform the intense math calculations at the required loop bandwidth.”
Wu points out that, on the other hand, a DSC implemented as a monolithic integrated circuit can reduce acoustic noise, mechanic noise, material cost, and complexity of control circuits and algorithms.
“Add current feedback loop with proper torque forward compensation,” he advises. “The torque forward compensation signal follows the estimated rotor position.”
Case Study Database
Get more exposure for your case study by uploading it to the Plant Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.
These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.
Click here to visit the Case Study Database and upload your case study.
2012 Salary Survey
In a year when manufacturing continued to lead the economic rebound, it makes sense that plant manager bonuses rebounded. Plant Engineering’s annual Salary Survey shows both wages and bonuses rose in 2012 after a retreat the year before.
Average salary across all job titles for plant floor management rose 3.5% to $95,446, and bonus compensation jumped to $15,162, a 4.2% increase from the 2010 level and double the 2011 total, which showed a sharp drop in bonus.