Dual-Winding Motor Phase Control for Ripple and Overcurrent
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Solution Overview
Problem
Existing electric machine systems face performance deterioration due to current ripples and overcurrent issues caused by mismatched voltage phases in winding sets, leading to torque and DC voltage ripples.
Innovation Solution
An electric machine system with a controller that adjusts the phase difference between voltage signals for two winding sets based on current variations, using pulse width adjustments to prevent overcurrent while suppressing ripples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If phases of voltages input to the winding sets are shifted to weaken current ripples, then current ripple is reduced, but magnitude of current through one winding set continuously increases causing overcurrent
Solution Approach 1:
The patent applies dynamics by making the phase difference between voltages applied to different winding sets variable rather than fixed. The control device dynamically adjusts the phase difference based on the magnitude of current flowing through the winding sets. When current magnitude increases, the phase difference is increased to prevent overcurrent; when current magnitude decreases, the phase difference is reduced to minimize current ripple. This dynamic adjustment resolves the contradiction between reducing current ripple and preventing overcurrent.
2Object-generated harmful factors
If phases of voltages are excessively shifted to reduce current ripple, then current ripple weakens, but inductance appears small due to mutual inductance influence causing overcurrent
Solution Approach 1:
The patent implements feedback control where the control device continuously monitors the magnitude of current flowing through the winding sets and uses this information to adjust the phase difference of applied voltages. The current magnitude serves as feedback that determines the optimal phase difference setting. This feedback mechanism ensures that the phase difference is always appropriate for the current conditions, preventing both excessive current ripple and overcurrent caused by reduced inductance.
3Device complexity
If multiple winding sets are controlled with matched voltage phases, then control simplicity is maintained, but torque ripple and DC voltage ripple are generated
Solution Approach 1:
The patent applies parameter changes by modifying the phase difference parameter of voltages applied to different winding sets. Instead of using a fixed phase difference (such as 0 degrees for simplicity), the system changes the phase difference parameter dynamically based on operating conditions. This parameter change allows the system to eliminate torque ripple and DC voltage ripple while maintaining manageable control complexity through systematic control strategies.
Data Source
AI summary
An electric machine system includes an electric machine and a controller. The controller controls input and output of a first voltage with respect to the first winding set, and input and output of a second voltage with respect to the second winding set. The controller includes an output unit and a setting unit. The output unit outputs a first signal for the input and output of the first voltage, and a second signal for the input and output of the second voltage. The setting unit sets a phase difference between the first signal and the second signal. The setting unit changes the phase difference in correspondence with a variation of the magnitude of at least one of a first current flowing through the first winding set, and a second current flowing through the second winding set.