Permanent Magnet Motor Controller Third Quadrant Voltage Convergence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional controllers for permanent magnet type rotary motors struggle to properly control electrification when the voltage magnitude is in the third quadrant, where the voltage advance is 180° or more, as they cannot converge the voltage to be less than the maximum source voltage.
Innovation Solution
A controller that includes a magnetic pole position detector, a current controller for vector control using rotatory magnetic flux coordinates, a current difference calculator to decompose voltage and current differences, and a target current corrector to adjust field-axis and torque-axis currents, allowing for proper electrification control even when the voltage advance is 180° or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If weak field control is performed by correcting only field-axis target current, then voltage magnitude can be converged in the first and second quadrants, but voltage magnitude cannot be converged when voltage advance is 180° or more (third quadrant)
Solution Approach 1:
The patent segments the current control into two independent components: field-axis current control and torque-axis current control. By separately calculating and correcting both field-axis current difference component (ΔId) and torque-axis current difference component (ΔIq), the system can independently adjust each component to achieve proper voltage convergence in all quadrants, including the third quadrant where conventional single-axis control fails.
Solution Approach 2:
The patent transitions from one-dimensional control (correcting only field-axis current) to two-dimensional control by introducing torque-axis current correction as a second dimension. This dual-axis correction approach in the dq-coordinate system enables the controller to handle voltage convergence issues in all four quadrants, adding dimensional capability to the control system.
2Device complexity
If conventional weak field control is used, then device complexity is low, but control precision deteriorates when voltage advance is 180° or more
Solution Approach 1:
The patent implements a feedback mechanism where the primary voltage magnitude is continuously monitored and compared against the maximum voltage. Based on this feedback, the system calculates voltage difference and subsequently current difference components in both field and torque axes. This closed-loop feedback ensures high control precision by continuously adjusting the current commands to maintain voltage within acceptable limits, even in the third quadrant condition.
3Ease of operation
If only field-axis target current is corrected, then control simplicity is maintained, but electrification control accuracy deteriorates in the third quadrant
Solution Approach 1:
The patent changes the control parameters from single-axis current correction to dual-axis current correction. By calculating both field-axis current difference component and torque-axis current difference component based on the primary voltage difference, the system achieves accurate electrification control in the third quadrant. This parameter expansion maintains operational simplicity through automated calculation while significantly improving control accuracy.
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
Enables effective electrification control by calculating and correcting field-axis and torque-axis current differences, ensuring the primary voltage is converged to the maximum voltage or less, thereby improving control in the third quadrant.
Implementation Method 1
an electric motor for rotating a rotator by the use of a magnet torque between a rotating magnetic field generated by the armature and a permanent magnet of the rotator
Implementation Method 2
a rotating torque between the rotating magnetic field and a magnet core of the rotator, that is, a reluctance torque
Implementation Method 3
a magnetic pole position detector detecting a magnetic pole position of the rotator
Implementation Method 4
a stator which has an armature generating a rotating magnetic field for rotating the rotator
Data Source
AI summary
A controller of a permanent magnet type rotary motor of the present invention includes: a current difference calculator decomposing a primary voltage difference which is a difference between a primary voltage of the permanent magnet type rotary motor and a maximum voltage corresponding to a source voltage, into a field-axis voltage difference component and a torque-axis voltage difference component in the rotatory magnetic flux coordinate by the use of a phase angle of the primary voltage, and calculating a field-axis current difference component and a torque-axis current difference component in the rotatory magnetic flux coordinate by the use of the voltage difference component, a field-axis inductance, and a torque-axis inductance; and a target current corrector correcting a field-axis target current and a torque-axis target current in the rotatory magnetic flux coordinate so that current difference components are zero.