EC Motor Torque Constant Calibration via Induced Voltage
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Solution Overview
Problem
Existing electronically commutated electric motors face challenges in accurately determining and controlling the motor torque constant due to manufacturing tolerances, temperature-dependent magnetic field strengths, and varying magnetic profiles, which affect torque generation and efficiency.
Innovation Solution
The control unit of the electric motor detects the frequency content of the motor torque constant, using sensors and Fourier transforms to generate a torque profile, allowing for precise calibration and control of the stator coils based on rotor position and temperature, thereby accounting for manufacturing tolerances and temperature effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the motor torque constant is determined using conventional methods, then the basic torque generation is achieved, but manufacturing tolerances and temperature effects cause inaccuracies in torque control
Solution Approach 1:
The control unit performs preliminary calibration during motor operation by detecting the induced voltage and determining the motor torque constant before using it for precise torque control. This preliminary determination of the actual torque constant compensates for manufacturing tolerances and temperature effects, enabling accurate torque control under varying conditions.
2Measurement precision
If the stator control is adjusted to compensate for torque variations, then torque accuracy is improved, but the system complexity increases
Solution Approach 1:
The control unit continuously detects the induced voltage in the stator coils and uses this feedback to determine the motor torque constant. Based on this real-time information, the control unit adjusts the stator control to maintain accurate torque generation, compensating for manufacturing tolerances and temperature effects without requiring complex additional hardware.
3Reliability
If the motor torque constant is calibrated during operation, then temperature-dependent effects are compensated, but the calibration time and computational load increase
Solution Approach 1:
The motor torque constant is calibrated during normal motor operation rather than requiring separate calibration procedures. The control unit continuously detects the induced voltage and determines the torque constant as part of the regular control loop, ensuring temperature compensation without adding dedicated calibration time or disrupting motor operation.
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
This approach enables precise recording and control of torque over a rotor revolution, improving mechanical and electrical efficiency by accurately determining the motor torque constant and adapting stator control accordingly, even under varying conditions.
Implementation Method 1
detecting an induced voltage from a stator coil of the stator or determining the induced voltage as a function of a stator coil current flowing through a stator coil and as a function of a rotor position signal representing a rotor position of the rotor and/or a rotor rotation frequency of the rotor
Implementation Method 2
a control unit, which is connected to the stator and is designed to control the stator, in particular the stator coils of the stator, to generate a rotary magnetic field
Implementation Method 3
generate a rotary magnetic field
Data Source
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AI summary
The invention relates to an electrically commutated electrical motor having a stator and having an in particular permanent-magnetically designed rotor. The electronically commutated electrical motor also has a control unit which is connected to the stator and designed to actuate the stator for generating a magnetic rotary field. The control unit is designed to detect a voltage induced in at least one stator coil of the stator and to determine a motor torque constant representing an achievable torque in dependence on a rotational speed signal representing a rotor circumferential frequency of the rotor. According to the invention, the control unit in the electronically commutated electrical motor of the aforementioned type is designed to detect a frequency content of the motor torque constant and to actuate the stator for generating a torque in dependence of the frequency content, in particular a frequency amplitude of the motor torque constant.