Dual-Winding Motor Control Using Shared Voltage Reference
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Solution Overview
Problem
In electric power steering systems, independent motor control can lead to differences in motor control amounts due to varying power supply voltages, causing vibration or noise, which results in an unpleasant driving experience.
Innovation Solution
A motor control device with dual controllers for each motor winding, featuring a power supply voltage selection circuitry that selects the lower voltage between systems, ensuring consistent d-axis target current computation and reducing vibration or noise by standardizing the power supply voltage across both systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If independent motor control is implemented in each system, then system independence and control flexibility are improved, but motor control amount consistency deteriorates due to power supply voltage differences
Solution Approach 1:
The patent applies equipotentiality by making both control systems operate at the same power supply voltage level. The first control system uses its own voltage, while the second control system uses the voltage from the first system, ensuring both systems have equal voltage potential. This eliminates voltage-induced control amount differences while preserving system independence.
Solution Approach 2:
The patent introduces an intermediary mechanism where the power supply voltage from one control system serves as the operating voltage for the other control system. This intermediary voltage reference ensures that both independently controlled systems operate under identical voltage conditions, maintaining control consistency without sacrificing independence.
2Adaptability or versatility
If different power supply voltages are used in each control system, then system flexibility is improved, but motor vibration and noise increase due to control amount differences
Solution Approach 1:
By ensuring both control systems operate at the same voltage level through the equipotentiality principle, the patent eliminates the root cause of control amount differences that lead to motor vibration and noise, while still allowing systems to function independently with flexible voltage sources.
3Stability of the object's composition
If voltage standardization is implemented across both systems, then motor control consistency is improved, but system independence is reduced
Solution Approach 1:
The patent uses an intermediary voltage reference approach where each system can independently source its voltage, but one system's voltage serves as the reference for the other. This maintains system independence in voltage sourcing while achieving control consistency through the intermediary voltage relationship.
Data Source
AI summary
A motor control device that enables a reduction of an unpleasant sensation caused by vibration or noise occurring in a motor is obtained. A motor control device including a first control unit that drives a first motor winding and a second control unit that drives a second motor winding is such that the first control unit selects the lower of values of an own power supply voltage and a power supply voltage of the second control unit and outputs a post-selection power supply voltage, and computes a target d-axis current, a target q-axis voltage, and a target d-axis voltage using the post-selection power supply voltage.