PMSM PWM Carrier Phase Control for Motor Vibration Suppression
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Solution Overview
Problem
Permanent magnet synchronous motors in electric and hybrid vehicles experience significant vibration and noise issues due to torque pulsation and electromagnetic excitation forces, particularly at low rotation speeds and across a broad range of speeds, which existing methods fail to effectively mitigate.
Innovation Solution
A motor control device that adjusts the carrier wave frequency to change the phase difference between the voltage command and the carrier wave based on the torque command and rotation speed, using a carrier frequency adjustment unit to generate a gate signal for the power converter, thereby performing pulse-width modulation and controlling the motor's operation to suppress vibration and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the carrier wave frequency is adjusted to suppress vibration and noise, then the phase difference between voltage command and carrier wave changes, but the motor control precision may be affected
Solution Approach 1:
The patent incorporates feedback mechanisms that continuously monitor the motor's actual performance and adjust the carrier wave frequency accordingly. This closed-loop control ensures that while the carrier frequency is varied to suppress vibrations and noises, the motor maintains accurate control through real-time compensation based on actual operating conditions.
Solution Approach 2:
The invention uses periodic modulation of the carrier wave with controlled phase differences to achieve both vibration suppression and precise control. By carefully designing the periodic nature of the PWM signals and their phase relationships, the system can reduce unwanted vibrations while maintaining the accuracy needed for precise motor positioning and speed control.
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
Effectively reduces vibration and noise in permanent magnet synchronous motors by synchronizing the phase of the carrier wave with the motor's operation, thereby minimizing the impact of torque pulsation and electromagnetic excitation forces across various speeds.
Implementation Method 1
a gate signal generation unit which performs pulse-width modulation on a voltage command according to a torque command using the carrier wave, thereby generating a gate signal for controlling an operation of the power converter
Implementation Method 2
The permanent magnet synchronous motor is driven by a magnet torque generated by the suction force or repulsive force arising between the armature magnetic flux and a magnetic flux of the permanent magnet
Implementation Method 3
the electromagnetic force generated in the radial direction of the motor acts as an excitation force (electromagnetic excitation force) which causes the stator or case of the motor to become deformed or vibrate
Data Source
AI summary
The vibration and noise generated in a permanent magnet synchronous motor are effectively suppressed. A motor control device 1 comprises: a triangular wave generation unit 17 which generates a triangular wave signal Tr that is a carrier wave, a carrier frequency adjustment unit 16 which adjusts a carrier frequency fc that represents a frequency of the triangular wave signal Tr, and a gate signal generation unit 18 which performs pulse-width modulation on three-phase voltage commands Vu*, Vv*, Vw* according to a torque command T* using the triangular wave signal Tr, thereby generating a gate signal for controlling an operation of an inverter. The carrier frequency adjustment unit 16 adjusts the carrier frequency fc so as to change a voltage phase error Δθv representing a phase difference of the three-phase voltage commands Vu*, Vv*, Vw* and the triangular wave signal Tr based on the torque command T*, and a rotation speed ωr of a motor.