Motor controller for electric blower motors
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Solution Overview
Problem
Existing motor controllers for electric blower motors face challenges in accurately estimating airflow at low airflow rate demands due to variations in blower designs and applications, leading to errors in airflow production.
Innovation Solution
A motor controller with a processor and communication interface that computes a torque set point using a polynomial algorithm based on airflow rate demand and motor speed, allowing for precise control of electrical power to the motor to generate consistent airflow, incorporating coefficient values to refine airflow estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a polynomial or constant airflow algorithm is used to estimate airflow based on motor torque and speed, then the system can operate in torque-control mode to produce approximately constant airflow, but the estimation accuracy deteriorates at low airflow rate demands due to various sources of variation in blower designs and applications
Solution Approach 1:
The patent changes the parameters of the airflow estimation algorithm by introducing a lookup table with pre-calibrated airflow values corresponding to different motor speeds and torque values. This lookup table approach replaces the generic polynomial algorithm with application-specific calibrated data, improving accuracy particularly at low airflow rates where the polynomial approach fails.
Solution Approach 2:
The patent performs preliminary calibration during the manufacturing process to determine actual airflow output for various motor speeds and torque values. This calibration data is stored in a lookup table before the blower is deployed, allowing the system to use pre-determined accurate values rather than estimating airflow during operation. This preliminary characterization eliminates the need for real-time complex calculations and improves accuracy.
2Reliability
If torque control is used to regulate motor output based on monitored speed, then the system can maintain approximately constant airflow, but the actual airflow varies according to blower construction and duct restrictions
Solution Approach 1:
The patent changes from using a universal polynomial algorithm to using application-specific parameters stored in a lookup table. During manufacturing, the actual airflow characteristics are measured and stored for that specific blower design. This allows the control system to adapt to the specific blower construction, duct configuration, and airflow restrictions of each application, maintaining reliable constant airflow despite variations in design.
Solution Approach 2:
The system uses feedback from monitored motor speed and torque values to query the lookup table and determine the appropriate airflow output. This feedback mechanism allows the system to continuously adjust motor torque based on actual operating conditions and the pre-calibrated characteristics of the specific blower installation, maintaining reliable airflow control.
Data Source
AI summary
A motor controller for an electric motor includes a drive circuit that regulates power supplied to a stator of the electric motor to turn a rotor. The motor controller includes a communication interface that receives coefficients. The motor controller includes a processor coupled to the drive circuit. The processor receives an airflow rate demand, computes a speed, computes a torque set point as a function of at least a sum of first and second terms. The first term is defined as the first coefficient multiplied by the airflow rate demand raised to a power greater than one, and the second term is defined as the second coefficient multiplied by the speed raised to a power greater than one. The processor controls the drive circuit based on the torque set point to supply electrical power to the electric motor.