Dual Submotor BLDC Motor for Steering Torque Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional brushless direct current (BLDC) motors in electric power steering systems face issues with torque imbalance and vibration due to broken winding branch circuits, leading to safety concerns such as short-circuit currents and braking torque when the motor fails, causing the steering wheel to lock.
Innovation Solution
A BLDC motor design featuring two sub-motors with independent stators and a common rotor, along with non-overlapping conductive terminal sets, allows for selective operation as a single motor or independently, ensuring steady torque output and preventing simultaneous failure of both sub-motors in case of a short-circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional BLDC motor windings are used with multiple parallel branch circuits, then the motor can provide sufficient power output, but when a branch circuit breaks it causes torque fluctuation and vibration
Solution Approach 1:
The motor is divided into two independent sub-motors (first sub-motor and second sub-motor), each with its own stator and winding system. This segmentation allows one sub-motor to continue operating independently if the other fails, preventing torque fluctuations and maintaining stable power output even when one branch circuit breaks.
2Ease of operation
If conventional BLDC motor windings are used, then the motor can operate normally, but when a winding breaks it causes unbalance between phases resulting in large torque fluctuation and vibration
Solution Approach 1:
The motor is divided into two independent sub-motors (first sub-motor and second sub-motor), each with its own stator and winding system. This segmentation allows one sub-motor to continue operating independently if the other fails, preventing torque fluctuations and maintaining stable power output even when one branch circuit breaks.
3Force
If conventional BLDC motor is used in steering system, then the driver can produce larger torque with less force, but when the motor fails it produces braking torque that prevents steering wheel rotation
Solution Approach 1:
The motor is divided into two independent sub-motors (first sub-motor and second sub-motor), each with its own stator and winding system. This segmentation allows one sub-motor to continue operating independently if the other fails, preventing torque fluctuations and maintaining stable power output even when one branch circuit breaks.
Solution Approach 2:
The independent dual-submotor design converts the potential harmful effect of complete motor failure into a beneficial redundancy system. When one sub-motor fails, the other continues to provide driving torque, transforming a catastrophic failure mode into a graceful degradation that maintains steering functionality.
4Power
If conventional BLDC motor is used, then the motor can provide sufficient power, but safety concerns arise when winding coils short-circuit
Solution Approach 1:
The motor is divided into two independent sub-motors (first sub-motor and second sub-motor), each with its own stator and winding system. This segmentation allows one sub-motor to continue operating independently if the other fails, preventing torque fluctuations and maintaining stable power output even when one branch circuit breaks.
Solution Approach 2:
The independent dual-submotor design provides beforehand cushioning against failure by having redundant motor systems. If one sub-motor experiences a short-circuit or other failure, the other sub-motor is already in place to immediately take over, cushioning the system against complete failure and maintaining safety.
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
The design provides reliable and safe operation by maintaining normal torque output even if one sub-motor experiences a short-circuit, enhancing the motor's reliability and safety in electric power steering systems.
Implementation Method 1
The first sub-motor and the second sub-motor comprise their respective stators that are energized independently and a common rotor
Data Source
AI summary
A BLDC includes an outer casing, and a first sub-motor and a second sub-motor mounted within the outer casing. The BLDC further includes a terminal hub, and a first conductive terminal set and a second conductive terminal set. The first and second sub-motor include their respective stators that are energized independently and a common rotor. The first conductive terminal set is configured as a power supply branch circuit for the stator of the first sub-motor, the second conductive terminal set is configured as a power supply branch circuit for the stator of the second sub-motor. The first and second sub-motors can be configured to selectively commonly operate as a single motor to output normal power or operate independently. When one sub-motor fails, the other sub-motor can independently operate to ensure reliability and safety of the motor.