Reluctance Machine Torque Control via Abrupt Current Switching
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Solution Overview
Problem
Conventional synchronous reluctance machines require a large number of stator slots to suppress harmonics and achieve a sinusoidal torque profile, leading to a complex winding design.
Innovation Solution
A method for operating a reluctance machine with a simplified stator winding by sequentially energizing the windings with constant current values changed abruptly based on the rotor angle, utilizing magnetic harmonics to generate a constant torque, and reducing the number of slots required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If sinusoidal current supply is used to optimize magnetic system variables, then torque constancy is improved, but the number of stator slots increases significantly
Solution Approach 1:
The patent applies periodic action by using discrete, time-varying current pulses applied to the stator windings at specific intervals corresponding to rotor position. Instead of continuous sinusoidal current, the system uses periodic current excitation with variable pulse widths and amplitudes to achieve torque production with fewer stator slots.
Solution Approach 2:
The patent changes the parameters of current supply from fixed sinusoidal waveforms to variable discrete current pulses with adjustable amplitude and duration. The control system dynamically adjusts current parameters based on rotor position and operating conditions to maintain torque constancy while reducing the number of stator slots required.
2Object-generated harmful factors
If distributed winding arrangement is used to approximate sinusoidal field exciter curve, then harmonic suppression is improved, but winding complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for complex distributed windings by using a simplified winding arrangement combined with advanced control. The system achieves harmonic suppression not through physical winding distribution but through controlled current excitation patterns that inherently minimize harmful harmonics.
Solution Approach 2:
The patent replaces the mechanical solution of complex distributed windings with an electronic control solution. Instead of using physical winding arrangements to achieve sinusoidal field distribution, the system uses electronic control of current pulses to achieve the same effect with simpler windings.
3Manufacturing precision
If abrupt energization state changes are implemented as function of rotor angle, then switching precision is improved, but control complexity increases
Solution Approach 1:
The patent implements feedback by continuously monitoring rotor position and using this information to precisely timing current pulse application. The control system adjusts the timing and duration of current pulses based on actual rotor position feedback to achieve accurate switching precision for torque production.
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 allows for a reduced number of stator slots while maintaining a constant torque, achieving good operating behavior with a homogeneous flux density distribution, and enabling the use of a rotor design similar to conventional synchronous reluctance machines.
Implementation Method 1
The position and amplitude of the flux density is determined by the change in reluctance of the rotor 1, i.e. H. depends on the resulting angle of rotation γ of the rotor
Data Source
Figure 1~3
Figure 4~6
Figure 7a~8b
AI summary
The invention relates to a method for operating a reluctance machine, which comprises a rotor composed of a soft magnetic material and having an even number of salient poles and a stator having a multi-strand offset diametral winding, wherein the strands of the diametral windings are supplied with currents that are phase-shifted from each other, and the current-supply states are changed abruptly in dependence on the rotor angle.