Sinusoidal Modulation Control for PMSM Using U-Shaped Waves
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Solution Overview
Problem
Conventional sinusoidal modulation control methods for permanent magnet synchronous motors (PMSMs) are complex and costly due to the need for vector control and precise coordinate transformations, which can affect control results and increase production costs.
Innovation Solution
A sinusoidal modulation control method and circuit that generates a full-wave U-shaped modulation wave using rotor position signals to produce a PWM control signal for an inverter, eliminating the need for stator current detection and vector coordinate transformations, thereby simplifying the control scheme and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional vector control methods are used for PMSM, then control precision can be improved, but device complexity and production costs increase due to coordinate transformations and current detection requirements
Solution Approach 1:
The patent extracts and eliminates the complex coordinate transformation module from the conventional vector control system. By using a simplified modulation wave generation approach that directly processes rotor position signals without requiring dq-axis transformations, the invention removes the problematic component while preserving the essential speed and position control functions.
Solution Approach 2:
Instead of following the conventional approach of transforming currents to dq-axis and then generating voltage commands, the patent inverts the control sequence by directly generating modulation waves from rotor position signals. This reverse engineering approach simplifies the control path while achieving the same torque control objective.
2Manufacturing precision
If vector control with coordinate transformations is implemented, then torque control performance can be improved, but production costs increase due to additional sensors and complex circuitry
Solution Approach 1:
The patent removes the requirement for complex coordinate transformation circuits and additional current sensors from the manufacturing process. By using a direct modulation wave generation method that works with basic rotor position signals, the invention eliminates expensive components while maintaining torque control performance.
Solution Approach 2:
The patent replaces expensive, complex coordinate transformation hardware with a simpler, more economical modulation circuit that achieves the same functional result. This substitution uses readily available components and standard processing techniques, significantly reducing production costs.
3Stability of the object's composition
If sinusoidal control current is used for PMSM, then torque stability and noise reduction are improved, but control complexity increases due to the need for precise current waveform generation
Solution Approach 1:
The patent pre-generates the sinusoidal modulation waves with appropriate frequency and amplitude characteristics before applying them to the motor. By preparing the sinusoidal control signals in advance through a dedicated modulation wave generation circuit, the system ensures smooth torque delivery without requiring complex real-time current waveform synthesis.
Data Source
AI summary
Disclosed herein are sinusoidal modulation control methods and circuits for PMSM. In one embodiment, a method can include: detecting rotor position information of the PMSM to obtain a rotor position signal and a rotor rotating speed measured value; comparing the rotating speed measured value against a reference rotating speed value to generate an error signal, and generating a first regulating voltage signal based on the error signal using a PI regulator; receiving the rotor position signal and the first regulating voltage signal, and generating a full-wave U-shaped modulation wave by using the rotor position signal as a time reference; generating a second U-shaped modulation wave by multiplying the full-wave U-shaped modulation wave with the first regulating voltage signal; comparing the second U-shaped modulation wave against a triangular wave to generate a PWM control signal that controls a switch of an inverter to regulate a current of the PMSM.