PMSM Starting Method Using Minimum Speed Feedback
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Solution Overview
Problem
The existing starting methods for permanent magnet synchronous motors are complex and unreliable, requiring multiple steps and parameter adjustments, especially when estimating low motor rotational speeds, which can lead to inaccurate estimations and potential failures.
Innovation Solution
A simplified starting method that uses a preset minimum rotational speed as feedback when the calculated speed is below this threshold, allowing direct closed-loop control, thereby eliminating the need for open-loop and locating steps and reducing potential failure risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the traditional three-step starting method (locating, open-loop control, closed-loop control) is used, then the motor can be started with reasonable control, but the control process becomes complex and requires repeated parameter adjustments
Solution Approach 1:
The patent merges the traditional three-step starting process (locating, open-loop control, closed-loop control) into a single closed-loop control process. By using a preset minimum rotational speed and comparing it with the calculated rotational speed to determine feedback speed, the patent eliminates the need for separate locating and open-loop control steps, thereby simplifying the control process while maintaining starting reliability
Solution Approach 2:
The patent introduces a preset minimum rotational speed parameter and uses it to dynamically determine the feedback rotational speed. When the calculated rotational speed is less than the preset minimum, the preset minimum is used as feedback; otherwise, the calculated rotational speed is used. This parameter-based approach replaces complex state switching and parameter adjustments with a simple comparison logic
2Ease of manufacture
If the position sensorless control method is used, then the control implementation is simplified, but the rotational speed estimation becomes inaccurate at low speeds
Solution Approach 1:
The patent implements a feedback mechanism where the feedback rotational speed is determined by comparing the calculated rotational speed with a preset minimum rotational speed. This feedback approach ensures that even when the calculated speed is inaccurate at low speeds, the system uses a reliable minimum threshold to maintain accurate control, thereby resolving the estimation accuracy problem while keeping the sensorless control implementation simple
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
This approach simplifies the starting process, enhances reliability by avoiding complex state switching and parameter adjustments, and ensures accurate motor control from the outset, improving the overall starting efficiency and stability of the motor.
Implementation Method 1
a U/V/W three-phase current is usually controlled by using a driver, to form an electromagnetic field. Since a rotor of the permanent magnet synchronous motor is a permanent magnet, the rotor would rotate under the action of the electromagnetic field formed by the U/V/W three-phase current.
Data Source
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AI summary
Implementations of the present application relate to a starting method and apparatus for a permanent magnet synchronous motor, a power system, and an unmanned aerial vehicle (UAV). The method includes: obtaining a current motor rotational speed and motor position information of the permanent magnet synchronous motor; determining whether the current motor rotational speed is less than a preset minimum rotational speed, and if the current motor rotational speed is less than the preset minimum rotational speed, using the preset minimum rotational speed as a feedback rotational speed; otherwise, using the current motor rotational speed as a feedback rotational speed; and performing closed-loop control on the permanent magnet synchronous motor according to the feedback rotational speed and the motor position information. In the implementations of the present application, the preset minimum rotational speed is set in advance. When the calculated current motor rotational speed is less than the preset minimum rotational speed, the preset minimum rotational speed is used as the feedback rotational speed. When the calculated current motor rotational speed is greater than the preset minimum rotational speed, the current motor rotational speed is used as the feedback rotational speed. In this way, direct closed-loop control can be implemented. Steps, such as complex status switching and adjustment on a relatively large number of parameters, in the prior art are abandoned, a permanent magnet synchronous motor starting manner, including three steps: locating, open-loop control, and closed-loop control, in the prior art is simplified, and the starting method is simpler. Moreover, potential failure risks in various states in the prior art are avoided, thereby effectively improving reliability of a starting process.