Sensorless Motor Startup Using Inverse Exponential Speed Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sensor-less motors face challenges in accurate speed and position estimation during initial start-up, leading to instability and loss of synchronization when transitioning from open-loop to closed-loop control.
Innovation Solution
A motor controller using an inverse exponential function with respect to time for open-loop control, based on mechanical properties like friction and inertia, to quickly achieve target speed and stabilize operation, followed by closed-loop control once sufficient speed is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional open-loop control with quadratic function is used for sensor-less motor start-up, then the control implementation is simple, but the motor speed increase is slow and synchronization is lost during transition to closed-loop control
Solution Approach 1:
The patent changes the mathematical function used for open-loop control from a conventional quadratic function to an inverse exponential function. This parameter change in the control algorithm enables faster motor speed increase while maintaining synchronization stability during the transition to closed-loop control, directly resolving the contradiction between speed increase rate and synchronization reliability.
2Device complexity
If open-loop control is used during initial start-up, then the control complexity is reduced, but accurate speed and position estimation becomes difficult leading to instability
Solution Approach 1:
The patent applies preliminary action by using an inverse exponential function to pre-establish accurate speed estimation during the open-loop start-up phase. This preliminary accurate estimation enables a successful transition to closed-loop control without requiring complex sensor hardware, thus maintaining low device complexity while improving measurement precision.
Data Source
AI summary
A motor controller adapted to be coupled to a motor having a rotor. The motor controller includes a storage device containing software. The motor controller also includes a processor core coupled to the storage device and adapted to be coupled to the motor. The processor core is configured to operate the motor in an open-loop control in response to determining a speed of the rotor determined based on an inverse exponential function with respect to time.