Torque Current Limiting Vector Control for Brushless Window Regulator Motors
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Solution Overview
Problem
Existing motor control systems for power operated actuators, such as window regulators, face challenges in meeting stringent safety standards due to high inertia caused by brushed DC motors, leading to delayed reaction times and increased pinch forces during obstacle encounters, which is difficult to comply with FMVSS118 S5 requirements.
Innovation Solution
A torque current limiting vector control system for brushless electric motors is implemented, which includes a vector control system that determines torque current based on angular velocity and adjusts pulse width modulation signals to limit torque current in response to detected pinch events, reducing the risk of pinch forces and improving reaction times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If brushed DC motors are used in window regulators, then the system has high inertia which provides stable operation, but the reaction time to pinch events is delayed and pinch forces increase
Solution Approach 1:
The patent replaces brushed DC motors with brushless DC motors, substituting a mechanical system with commutators and brushes with an electronic commutation system. This substitution eliminates the high inertia associated with brushed motors while enabling precise electronic control through vector control algorithms, thereby reducing reaction time to pinch events while maintaining system stability through controlled torque delivery.
Solution Approach 2:
The patent implements dynamic torque control through vector control of the brushless motor. The control system continuously adjusts motor parameters including current magnitude and phase angle based on real-time feedback, enabling the system to rapidly respond to pinch events by modulating torque output. This dynamic control allows the system to transition from high-torque operation to rapid deceleration within milliseconds.
2Loss of time
If light weight brushed DC motors are used to reduce system inertia, then response time improves, but the motors are limited to small, low mass windows and cannot handle larger window applications
Solution Approach 1:
The patent employs brushless DC motors with electronic vector control that can operate across a wide range of torque and speed conditions. The electronic control system adjusts motor parameters dynamically, allowing the same motor design to effectively drive both small and large windows. This universality is achieved through programmable control algorithms that adapt torque output to match the specific load requirements of different window sizes and masses.
Solution Approach 2:
The patent utilizes parameter changes in the electronic control system to adapt motor performance to different window applications. By modifying control parameters such as current limits, switching frequencies, and torque constants through software configuration, the same physical motor can be optimized for different window sizes. This allows a single motor design to serve multiple applications from small to large windows.
3Productivity
If high torque is applied to move the window quickly, then productivity increases, but pinch forces increase during obstacle encounters
Solution Approach 1:
The patent implements feedback control through monitoring of motor current, voltage, and position sensors during window operation. When an obstacle is detected through changes in current draw or position feedback, the control system immediately adjusts torque output to reduce pinch forces. This feedback mechanism allows the system to maintain high productivity during normal operation while automatically reducing harmful forces when obstacles are encountered.
Solution Approach 2:
The patent incorporates preliminary anti-action through the torque limiting vector control algorithm that proactively prevents excessive pinch forces. The control system is programmed with safety thresholds and predetermined response protocols that activate before dangerous pinch forces can develop. When potential pinch conditions are detected through sensor feedback, the system preemptively reduces torque to prevent harm, rather than reacting after damage occurs.
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 system effectively reduces pinch forces and enhances reaction times by limiting torque current during pinch events, enabling compliance with FMVSS118 S5 standards and improving safety and functionality in power operated actuators.
Implementation Method 1
a brushless electric motor (1) of a power operated actuator (10) of a closure panel (11) of a vehicle (1010)
Implementation Method 2
the vector torque current limiter (54) is configured to determine the torque current drawn, receive the measured angular velocity (ω) of the brushless electric motor (1), determine whether there is a reduction of the measured angular velocity (ω) relative to a predetermined speed limit
Data Source
AI summary
A motor control system for controlling a brushless electric motor of a power operated actuator of a closure panel of a vehicle and method of operating the control system are provided. The control system includes a vector control system configured to receive a torque current based on a measured angular velocity of the motor and current of each of the phases and determine corresponding stationary reference frame voltages. The vector control system outputs pulse width modulation signals to the motor. A vector torque current limiter couples to the vector control system and the motor and is configured to determine the torque current drawn, receive the measured angular velocity and determine whether there is a reduction of the measured angular velocity and detects a pinch event and reduces the torque current in response to determining there is a reduction of the measured angular velocity of the brushless electric motor.