Motor Vector Control via PPM Signal for UAV Stability
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Solution Overview
Problem
Current motor control methods for unmanned aerial vehicles, such as three-phase brushless direct current motors, experience torque pulsation and vibration due to square wave control, and issues with speed closed-loop control lead to loss of control and strong jitter, affecting aircraft stability.
Innovation Solution
A motor vector control method using Pulse Position Modulation (PPM) signals to perform direct voltage control, calculating d-axis and q-axis voltages, and applying vector control to reduce torque pulsation and jitter, thereby stabilizing the aircraft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If six-beat type square wave speed regulator is used to control motor speed, then motor speed can be regulated, but large torque pulsation is generated causing vibration and noise
Solution Approach 1:
The patent changes the control parameter from square wave duty ratio control to sine wave current control. By using sine wave current instead of square wave current, and implementing continuous voltage vector control according to rotor position, the torque pulsation is significantly reduced while maintaining speed regulation capability
Solution Approach 2:
The patent implements periodic voltage vector control where the voltage vector is continuously adjusted according to the rotor position within each electric angle period. This periodic control action ensures smooth torque output and eliminates the torque pulsation caused by discrete six-beat square wave control
2Speed
If speed closed-loop control is applied to aircraft, then speed control is achieved, but loss of control occurs due to voltage reduction at highest rotating speed
Solution Approach 1:
The patent changes the control parameter from speed-based control to direct voltage control. By directly controlling the voltage vector according to rotor position and receiving pulse width signals, the system maintains reliable control across the entire speed range without the loss of control issue that occurs in speed closed-loop control when battery voltage reduces at highest speeds
3Speed
If speed closed-loop control is applied to aircraft, then speed control is achieved, but strong jitter occurs during attitude stabilization
Solution Approach 1:
The patent changes from speed closed-loop control to direct voltage control with sine wave current output. This parameter change eliminates the rapid speed changes and torque fluctuations that cause strong jitter during attitude stabilization, providing smooth and stable aircraft operation
Solution Approach 2:
The patent implements continuous periodic voltage vector control according to rotor position, which provides smooth torque output. This periodic control action prevents the rapid torque changes that occur in speed closed-loop control during attitude stabilization, thereby eliminating strong jitter and improving aircraft stability
Data Source
AI summary
A motor vector control method and device, and an aircraft are provided. The method includes: receiving a Pulse Position Modulation (PPM) signal; acquiring a first given voltage signal of a motor according to the PPM signal; adopting a control manner of giving a d-axis current 0, to acquire a d-axis voltage of the motor; and calculating a q-axis voltage of the motor at the next moment according to the first given voltage signal and the d-axis voltage of the motor, and performing vector control on the motor according to the d-axis voltage of the motor and the q-axis voltage of the motor at the next moment.