PM Motor Power Control for Constant HVAC Airflow
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Solution Overview
Problem
Current methods for constant airflow control in HVAC systems using torque as a control variable are complex, costly, and not suitable for steady-state control, as torque is difficult to measure and not a consumer-friendly or regulatory-compliant parameter.
Innovation Solution
A direct power control method for PM motors in HVAC systems, utilizing a concise algorithm that measures and adjusts motor input power to maintain constant airflow, which is easily measurable and accurate, and suitable for steady-state control, reducing costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If torque control is used for constant airflow control, then the control can adapt to dynamic conditions, but the system complexity increases and measurement precision deteriorates because torque is difficult to measure
Solution Approach 1:
The patent changes the control parameter from torque to input power. Input power is calculated from easily measurable electrical parameters (voltage and current), avoiding the complexity of torque measurement while maintaining effective control capability. The control method uses input power as the key variable to regulate motor operation for constant airflow.
Solution Approach 2:
The patent replaces mechanical torque measurement with electrical parameter measurement. Instead of measuring mechanical torque directly, the system calculates input power from electrical voltage and current measurements, substituting a complex mechanical measurement system with a simpler electrical measurement system.
2Measurement precision
If air flow meter is installed for constant airflow control, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts the airflow measurement function from the control system by eliminating the need for physical air flow meters. Instead of measuring airflow directly, the system infers airflow conditions through motor input power measurements and calculations, removing the complex measurement device while maintaining control capability.
Solution Approach 2:
The patent uses motor input power as an intermediary parameter to represent airflow conditions. Rather than directly measuring airflow, the system measures input power and uses it to indirectly control and monitor airflow, providing a simpler measurement approach.
3Manufacturing precision
If logarithmic computations or high-order polynomials are used for constant airflow control, then control accuracy improves, but device complexity and computational requirements increase
Solution Approach 1:
The patent changes the computational approach by using input power as the control parameter instead of requiring complex logarithmic or high-order polynomial calculations. The input power-based control method achieves constant airflow control with simpler mathematical operations, reducing MCU computational requirements.
4Adaptability or versatility
If torque control is used, then dynamic control capability is maintained, but ease of operation deteriorates because torque is not a consumer-friendly parameter
Solution Approach 1:
The patent changes the control parameter from torque to input power. Input power is a more intuitive parameter that can be related to energy consumption and operational cost, making it easier for consumers to understand and relate to system operation while maintaining effective control capability.
Data Source
AI summary
A control method for constant airflow controlled by a direct power-controlled PM motor, wherein the PM motor is installed in an HVAC system to drive the rotation of a fan wheel, and wherein the PM motor has a stator component, permanent magnet rotor components, and a motor controller. In some embodiments, the motor controller includes an operation parameters sensing circuit and a microprocessor.