Motor controller for electric blowers
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Solution Overview
Problem
Existing motor controllers struggle to maintain constant airflow production in backward-curved electric blowers due to multiple airflow values at given torque and speed conditions, especially at high airflow values, which limits their effectiveness in HVAC and refrigeration systems.
Innovation Solution
A motor controller that computes system resistance based on airflow demand and feedback parameters, using correlations among torque, speed, and airflow to adjust electrical power supply to the motor, enabling operation in torque or speed control modes to achieve constant airflow production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If backward-curved blower is used to improve efficiency, then energy consumption is reduced, but airflow control precision deteriorates due to multiple airflow values at given torque and speed
Solution Approach 1:
The patent implements dynamic switching between torque-control mode and speed-control mode based on the operating region. The controller dynamically adjusts the control strategy: using torque-control for low airflow regions and speed-control for high airflow regions, thereby resolving the multi-valued airflow problem while maintaining efficiency benefits of backward-curved blowers
Solution Approach 2:
The patent changes the control parameter from fixed (either torque or speed only) to variable (switching between torque and speed based on operating conditions). By monitoring actual airflow and comparing with demanded airflow, the system adjusts which parameter to control, enabling precise airflow control across the entire operating range while maintaining energy efficiency
2Ease of operation
If traditional torque-control or speed-control mode is used, then control simplicity is maintained, but constant airflow production fails at high airflow values for backward-curved blowers
Solution Approach 1:
The controller dynamically switches between torque-control and speed-control modes based on the operating region and airflow demand. This dynamic adaptation allows the system to maintain constant airflow production across all operating conditions while preserving the simplicity of control through automated mode selection based on predefined criteria
3Productivity
If airflow demand is increased for high airflow production, then ventilation effectiveness improves, but control accuracy deteriorates due to multiple possible airflow values
Solution Approach 1:
The system dynamically switches to speed-control mode when high airflow is demanded, as this mode provides unique correspondence between control parameter and airflow output in the high airflow region. The controller monitors the operating region and adjusts the control strategy accordingly, ensuring accurate airflow control even at high productivity levels
Solution Approach 2:
The patent implements feedback control by monitoring actual airflow and comparing it with demanded airflow. Based on this feedback and the identified operating region, the controller adjusts the control mode and parameters to achieve accurate airflow control, resolving the multi-valued problem in high airflow regions
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
Enables efficient and accurate constant airflow production in backward-curved blowers while maintaining efficiency benefits over radial or forward-curved blowers, improving thermal comfort and energy savings in HVAC systems.
Implementation Method 1
The drive circuit is configured to regulate electrical power supplied to a stator of the electric motor to turn a rotor of the electric motor and generate the airflow
Data Source
AI summary
A motor controller for an electric motor for driving a blower to generate an airflow. The motor controller includes a processor and a drive circuit configured to regulate power supplied to the motor to turn the blower. The processor computes a system resistance for the blower based on a fixed set point for a first control parameter and a feedback parameter. The processor receives an airflow rate demand value and computes an operating set point for a second control parameter based on the system resistance and the airflow rate demand value. The processor controls the drive circuit based on the operating set point to supply electrical power to the electric motor and to operate the blower to generate the airflow.