Electric Blower Motor Control for Constant Airflow Under Duct Resistance
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Solution Overview
Problem
Existing control systems for electric motors in fluid moving apparatuses, such as blowers and fans, struggle to maintain constant fluid-flow production due to variations in airflow output caused by blower construction or duct restrictions, leading to inefficiencies in HVAC and refrigeration systems.
Innovation Solution
A control system that characterizes fluid-flow production using correlations between motor torque, speed, and fluid-flow, employing a fluid-flow algorithm to determine operating setpoints for electric motors, allowing for constant fluid-flow generation by adjusting torque or speed based on demand and system resistance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional torque-control or speed-control mode is used, then the control system can operate the electric motor, but it cannot effectively produce a demanded fluid-flow due to multiple different fluid-flows at given torque and speed
Solution Approach 1:
The patent changes the control parameter from traditional torque or speed control to power control. By controlling the power supplied to the motor through the relationship P=T×ω (power=torque×angular velocity), the system can uniquely determine the operating point on the fluid-flow characteristic curve, thereby achieving accurate and consistent fluid-flow production demand.
2Adaptability or versatility
If the blower construction or duct restrictions vary, then the system must adapt to different configurations, but the actual airflow output varies and cannot maintain constant fluid-flow
Solution Approach 1:
The patent implements a feedback control mechanism where the actual fluid-flow output is measured and compared with the demanded fluid-flow. The controller adjusts the power supplied to the motor based on this feedback to minimize the difference between actual and demanded flow, thereby maintaining constant fluid-flow output despite variations in blower construction or duct restrictions.
3Ease of operation
If the control system adjusts torque or speed to meet fluid-flow demand, then it can respond to demand changes, but it cannot account for system resistance changes caused by contamination or duct modifications
Solution Approach 1:
The control system continuously monitors the actual fluid-flow output and uses this feedback to detect changes in system resistance. When contamination or duct modifications cause resistance changes, the feedback mechanism enables the controller to adjust the power supply accordingly to maintain the demanded fluid-flow level.
Data Source
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AI summary
A control system for an electric motor (106) configured to drive a fluid-moving apparatus. The control system includes a drive circuit (120) and a processor (114, 201) coupled in communication with the drive circuit (120). The processor (114, 201) is configured to control the drive circuit (120) to operate the electric motor (106) at a plurality of control values of a control parameter and determine, for each of the plurality of control values, a fluid-flow value and a feedback value, the feedback value corresponding to a feedback parameter, compute a mathematical relationship between fluid-flow rate and one of the control parameter or the feedback parameter, receive a fluid-flow rate demand value, compute an operating setpoint for the control parameter based on the fluid-flow rate demand value and the computed mathematical relationship, and control the drive circuit (120) to operate the electric motor (106) at the operating setpoint.