ECM Motor Constant Torque Control via Simplified Bus Current Algorithm
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Solution Overview
Problem
Current constant torque control modes for electronically commutated motors (ECM) are complex, requiring high arithmetic capability from CPUs and resulting in high production costs and poor control accuracy.
Innovation Solution
A method for controlling ECM motors using a simple mathematical model and algorithm, involving a microprocessor that calculates and adjusts the target bus current based on a function Itad=F(T,P) to achieve closed-loop control, reducing the number of control variables and operational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vector control mode is used for constant torque control, then control accuracy is improved, but device complexity and production costs increase due to complicated mathematical models and high CPU arithmetic requirements
Solution Approach 1:
The patent extracts and eliminates the complex mathematical models and high-arithmetic operations from the control system. Instead of using traditional vector control with complicated calculations, the invention uses a simplified control approach that achieves constant torque control without requiring high CPU arithmetic capability, thereby reducing device complexity while maintaining control accuracy.
Solution Approach 2:
The patent changes the control parameters and control strategy from traditional vector control to a simplified control mode. By altering the mathematical model and control algorithm parameters, the system achieves the same control accuracy with significantly reduced computational complexity, allowing use of lower-cost microcontrollers.
2Adaptability or versatility
If scale control of bus current is used for constant torque control, then control flexibility is improved, but control accuracy deteriorates due to multiple variables and complicated control
Solution Approach 1:
The patent removes the multiple variables and complex control logic from the bus current control system. By extracting unnecessary control elements and simplifying the control algorithm, the system maintains flexibility in controlling the ECM motor while achieving precise control accuracy through a streamlined control approach with fewer variables.
3Measurement precision
If high-capability CPU is used for vector control, then control accuracy is improved, but production costs increase
Solution Approach 1:
The patent employs a cheaper, lower-capability microcontroller that suffices for the control task. By using a less expensive processing unit with adequate but not excessive computational capability, the system achieves the required control accuracy while significantly reducing production costs associated with high-performance CPUs.
Solution Approach 2:
The patent optimizes the control algorithm parameters to match the capabilities of lower-cost microcontrollers. By adjusting the mathematical model and control strategy parameters, the system achieves accurate constant torque control using inexpensive processing hardware, thereby reducing overall production costs while maintaining control precision.
Data Source
AI summary
A method for controlling an ECM motor to output a constant torque. The method includes: 1) entering a target torque value T0 from an external device; when the motor is in a non-use state, starting the motor, and allowing the microprocessor to acquire an original output voltage value P chopped by a PWM signal; when the motor is in a running state, allowing the microprocessor to acquire a current output voltage value P chopped by the PWM signal; 2) enabling the microprocessor to calculate a target bus current value Itad using the function Itad=F(T,P) according to the target torque value T0 and the output voltage value P chopped by the PWM signal; and detecting a real-time bus current Ibus; and 3) allowing the microprocessor to compare the target bus current value Itad with the real-time bus current Ibus for conducting a closed-loop control.