PMSM Torque Compensation via Temperature-Adjusted Direct Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Permanent magnet synchronous motors (PMSMs) face challenges in maintaining accurate torque delivery due to temperature variations, which affect the magnetic properties of permanent magnets, leading to inefficiencies and potential operation outside optimal regions.
Innovation Solution
A method that adjusts the direct and quadrature components of the winding current based on temperature, using pulse width modulation commands to an inverter, ensuring torque compensation and optimizing operation within the motor's achievable region for efficient torque production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature compensation is not applied, then the control system remains simple, but torque delivery accuracy deteriorates due to temperature-induced magnetic property changes
Solution Approach 1:
The patent applies parameter changes by adjusting the direct component of winding current based on temperature variations. The control system modifies current parameters (Id component) in response to temperature changes to compensate for magnetic property variations in permanent magnets, thereby maintaining accurate torque delivery without requiring fundamental changes to the control architecture.
2Measurement precision
If the direct component of winding current is increased to compensate for temperature, then torque delivery accuracy improves, but energy consumption increases
Solution Approach 1:
The patent implements partial action by adjusting only the direct component of the winding current (Id) rather than increasing the total current magnitude. This selective adjustment compensates for temperature effects on magnetic properties while minimizing additional energy consumption, as the quadrature component (Iq) which directly produces torque remains optimized for energy efficiency.
3Measurement precision
If temperature compensation is implemented, then torque delivery accuracy improves, but the control algorithm complexity increases
Solution Approach 1:
The patent applies segmentation by separating the current control into distinct components (direct component Id and quadrature component Iq) and applying temperature compensation only to the direct component. This segmented approach simplifies the control algorithm compared to comprehensive re-calculation of all current parameters, as it isolates the temperature compensation function to a specific current component.
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 effectively compensates for temperature-induced changes in magnetic strength, maintaining efficient torque delivery and preventing operation outside the motor's achievable region, thus enhancing overall efficiency and performance.
Implementation Method 1
The inverter is configured to supply the electric machine a winding current... The controller is configured to issue pulse width modulation commands to the inverter to adjust the winding current
Implementation Method 2
These winding currents induce a rotating magnetic field which may be out of phase with the rotor. The resulting shaft torque depends upon both the magnitude of the magnetic field and the phase angle relative to the rotor.
Implementation Method 3
The magnetic properties of the permanent magnets are impacted by temperature which impacts the resulting torque
Data Source
AI summary
A vehicle includes one or more inverter-fed electric machines such as permanent magnet synchronous motors. In response to a torque request, a controller issues commands to an inverter calculated to cause the motor to produce the requested torque at the current temperature. A method adjusts the direct component of the winding current such that the requested torque is delivered efficiently. For a given rotor speed, bus voltage, and torque, the direct component increases as the temperature increases.