PMSM Phase Advance Control for High-Speed Voltage Limiting
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Solution Overview
Problem
Existing permanent magnet synchronous motor (PMSM) control systems face limitations in maintaining optimal torque production and efficiency at high speeds due to the inability to manage back-emf and voltage drops, leading to exceeding the power inverter's voltage capacity.
Innovation Solution
A method and system for calculating a phase advance angle in the DQ reference frame based on stator voltage demand components (Vq and/or Vd) using threshold comparisons and proportional control, allowing the motor to operate efficiently by adjusting the DQ reference frame phase to maintain stator voltage within limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor operates at higher speeds to increase productivity, then the back-emf and voltage drops increase, causing the stator voltage to exceed the power inverter's capacity
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the phase advance angle based on the monitored stator voltage demand. When voltage demand exceeds a threshold, the phase advance angle is increased to reduce the required stator voltage magnitude, allowing the motor to operate at higher speeds without exceeding inverter voltage capacity.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the stator voltage demand (Vq and/or Vd components) and using this information to calculate and adjust the phase advance angle. This closed-loop feedback mechanism ensures that the phase advance is optimized to prevent voltage exceedance while maintaining high-speed operation.
2Productivity
If the DQ reference frame phase is advanced to reduce stator voltage demand, then the motor can operate at higher speeds, but the control algorithm complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating the phase advance angle based on the monitored voltage demand before the voltage exceedance occurs. The control algorithm proactively adjusts the DQ reference frame phase to prevent voltage saturation, rather than reacting after the problem arises.
Solution Approach 2:
The patent uses parameter changes by modifying the phase advance angle as a controllable parameter to simplify the control approach. Instead of complex multi-variable control, the invention focuses on adjusting a single key parameter (phase advance angle) based on voltage demand, reducing overall control complexity while achieving high-speed operation.
3Object-affected harmful factors
If the phase advance angle is increased to manage voltage drops, then the stator voltage remains within limits, but the torque production efficiency decreases
Solution Approach 1:
The patent applies dynamics by making the phase advance angle a dynamic parameter that continuously adapts to operating conditions. The phase advance angle is adjusted in real-time based on the monitored stator voltage demand, allowing the system to optimize between voltage management and torque efficiency for each operating point rather than using a fixed phase advance.
Solution Approach 2:
The patent uses parameter changes to optimize the phase advance angle based on the specific operating conditions. By monitoring voltage demand and adjusting the phase advance angle accordingly, the system changes the electrical parameters to maintain optimal torque production efficiency while preventing voltage exceedance at different speed and load conditions.
Data Source
AI summary
There is provided herein a method of advancing phase of a DQ reference frame in a Field Oriented Control, FOC, algorithm for a permanent magnet motor. The method comprises: monitoring a component of the stator voltage demand of the permanent magnet motor, when the component of the stator voltage demand surpasses a threshold, calculating a phase advance angle, θadv, based on a gain multiplied by the difference between the component of stator voltage demand and the threshold; and advancing phase of the DQ reference frame in the FOC algorithm based on the calculated phase advance angle, up to a maximum phase advance angle when motor speed is positive, or down to a minimum phase angle when motor speed is negative.