SPM Motor Control Using Direct Peak Torque Calculation

Solution Overview

Problem

Existing control algorithms for surface-mounted permanent magnet (SPM) motors require iterative methods to determine maximum achievable torque, leading to increased processor load and computation time, which is undesirable in cost-sensitive applications.

Innovation Solution

A method and system for controlling SPM motors that determine a peak torque value and limit torque commands without iteration, using a voltage angle relative to the q-axis and available inverter voltage to calculate peak torque, thereby simplifying calculations and reducing processor load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If iteration methods are used to determine maximum achievable torque, then the control algorithm can be applied to IPM motor types, but processor load increases and computation time increases

Engineering Contradiction:

Improveapplicability to IPM motor typesVSAvoidprocessor load

Core Design Contradiction:

Adaptability or versatilityVSPower

Solution Approach 1:

The patent extracts and removes the iterative calculation component from the control algorithm, replacing it with a direct calculation method that determines peak torque using closed-form equations based on voltage angle and available voltage, thereby eliminating the computational burden while preserving the core functionality for SPM motors

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using iteration to find the maximum torque point (forward approach), the patent inverts the approach by directly calculating the voltage angle that maximizes torque and then computing the corresponding peak torque value (reverse approach), thus avoiding iterative search entirely

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If iteration methods are used to determine maximum achievable torque, then the control algorithm can be applied to IPM motor types, but computation time increases

Engineering Contradiction:

Improveapplicability to IPM motor typesVSAvoidcomputation time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent extracts and removes the iterative calculation component from the control algorithm, replacing it with a direct calculation method that determines peak torque using closed-form equations based on voltage angle and available voltage, thereby eliminating the computational burden while preserving the core functionality for SPM motors

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary calculation of the voltage angle using direct trigonometric relationships before computing the peak torque value, ensuring that all necessary parameters are ready in advance without requiring iterative refinement during real-time operation

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If conventional control algorithms are used, then maximum torque can be determined, but convergence issues occur

Engineering Contradiction:

Improvetorque determination accuracyVSAvoidconvergence reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent extracts and removes the iterative calculation component from the control algorithm, replacing it with a direct calculation method that determines peak torque using closed-form equations based on voltage angle and available voltage, thereby eliminating the computational burden while preserving the core functionality for SPM motors

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a self-sufficient calculation system that directly computes peak torque without requiring external iterative refinement or convergence checks, making the system inherently reliable and free from convergence issues by eliminating the iterative loop entirely

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20250309806A1System and method for surface-mounted permanent magnet motor control using peak torque

Publication Date: 2025.10.02 STEERING SOLUTIONS IP HOLDING CORP

AI summary

Technical solutions are described for controlling a surface-mounted permanent magnet (SPM) motor. A method for controlling a surface-mounted permanent magnet (SPM) motor includes: determining a peak torque value; determining a limited torque command based on a torque command and which does not exceed the peak torque value; determining, based on the limited torque command, a voltage command; and commanding, based on the voltage command, an inverter to apply an output voltage to the SPM motor. Determining the peak torque value includes: determining a voltage angle of the output voltage relative to a q-axis; and calculating the peak torque value based on the voltage angle of the output voltage and based on an available voltage to an input of the inverter.