Sensorless Motor Drive Using Magnetic Flux Phase Estimation
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Solution Overview
Problem
Existing driving systems for electric motors face challenges in cost reduction while maintaining efficient control of drive voltage, particularly when using sensorless methods without a microcomputer, requiring simpler processing due to limited processing capacity of integrated circuits.
Innovation Solution
A driving device incorporating a phase estimator and voltage controller that estimates the phase of stator interlinkage magnetic flux and sets voltage commands based on orthogonal vector components, allowing for sensorless control of drive voltage without detecting rotor position, implemented on an integrated circuit for cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sensorless method is used to control drive voltage without a rotor position sensor, then cost is reduced, but control precision deteriorates
Solution Approach 1:
The patent introduces a magnetic flux phase as an intermediary parameter to indirectly represent rotor position information. Instead of directly measuring rotor position with a sensor, the system estimates the magnetic flux phase from voltage and current measurements, which serves as a mediator to achieve position-dependent control without physical sensors. This resolves the contradiction by maintaining control precision through indirect measurement while eliminating sensor costs.
Solution Approach 2:
The patent replaces the mechanical/physical sensor-based position detection system with an electrical estimation system. By using voltage commands, current measurements, and magnetic flux calculations to derive position information, the system substitutes direct mechanical measurement with electrical field-based inference, reducing cost while preserving control capability.
2Ease of manufacture
If control is implemented on an integrated circuit instead of a microcomputer, then cost is reduced, but processing capacity deteriorates
Solution Approach 1:
The patent extracts and isolates only the essential control functions needed for sensorless motor control into the integrated circuit. By removing unnecessary processing capabilities and focusing solely on voltage command generation, current measurement, and magnetic flux phase estimation, the system achieves adequate processing capacity for the specific application without the overhead of a full microcomputer, thus reducing cost while maintaining sufficient productivity.
Solution Approach 2:
The patent changes the control parameters and methods to be suitable for limited processing capacity. By using simplified estimation algorithms and pre-calculated relationships rather than complex real-time computations, the system adapts the control strategy to match the capabilities of the integrated circuit, enabling cost-effective implementation without sacrificing essential control functionality.
3Device complexity
If rotor position detection is eliminated, then device complexity is reduced, but reliability of control deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the estimated magnetic flux phase is continuously updated based on actual voltage commands and current measurements. This closed-loop estimation process provides feedback that corrects and refines the position information over time, maintaining control reliability without requiring direct sensor feedback, thus reducing device complexity while preserving reliability.
Data Source
AI summary
A driving device of one embodiment includes a phase estimator and a voltage controller. The phase estimator estimates a phase of stator interlinkage magnetic flux of an electric motor based on a current flowing through the electric motor, a voltage command of a drive voltage applied to the electric motor, and a winding resistance value of the electric motor. The voltage controller acquires a first voltage vector component in a direction in which the stator interlinkage magnetic flux acts and a second voltage vector component in a direction which is orthogonal to the direction in which the stator interlinkage magnetic flux acts for the voltage command of the drive voltage, and sets the voltage command of the drive voltage based on the first voltage vector component and the second voltage vector component.