IPM Motor Control Voltage Adaptation

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Solution Overview

Problem

IPM motor control systems face challenges in maintaining efficient current regulation due to fluctuating dc bus voltage levels, particularly during motoring and braking modes, especially in battery applications, as existing methods are calibrated only at nominal voltage levels and do not account for varying motor operating conditions.

Innovation Solution

The system adjusts motor operating points and utilizes a boosted dc bus voltage when available to increase output torque and power, and adjusts current control when the voltage is lower than nominal to ensure robust operation, employing a voltage compensation coefficient to account for varying magnet strength and inductances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If motor control is calibrated only at nominal dc bus voltage level, then device complexity is reduced, but current regulation performance deteriorates under fluctuating voltage conditions

Engineering Contradiction:
Improvecontrol calibration complexityVSAvoidcurrent regulation performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of motor operating points based on real-time detection of dc bus voltage fluctuations. The controller continuously monitors voltage levels and adapts the motor operating parameters accordingly, transitioning from static nominal-voltage calibration to dynamic voltage-adaptive control, thereby maintaining reliable current regulation across varying voltage conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters of the IPM motor based on the detected dc bus voltage level. When voltage fluctuations are detected, the controller adjusts motor operating points (such as current references and switching strategies) to match the actual voltage conditions, ensuring optimal performance and reliable current regulation without requiring complex multi-voltage calibration

Inventive Principle:
Principle #35Parameter changes

2Power

If boosted dc bus voltage is utilized during motor regeneration, then torque and power output increase, but control complexity increases

Engineering Contradiction:
Improvemotor output powerVSAvoidcontrol system complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent enables the motor control system to automatically detect and utilize boosted dc bus voltage conditions generated during motor regeneration. The controller self-adjusts by detecting the elevated voltage level and automatically modifying operating points to exploit the available energy, increasing torque and power output without requiring external intervention or complex additional hardware

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent prepares the control system to handle boosted voltage conditions by having pre-established operating point adjustment strategies. When regeneration occurs and voltage boosts, the controller has predetermined adjustment protocols ready to activate, allowing seamless exploitation of the boosted voltage for enhanced power output without introducing complex real-time decision-making mechanisms

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2681838B1Interior permanent magnet machine systems
Publication Date: 2020.12.16 DEERE & CO
  • EP2681838B1 patent drawingFigure 1
  • EP2681838B1 patent drawingFigure 2
  • EP2681838B1 patent drawingFigure 3

AI summary

Example embodiments disclose an Interior Permanent Magnet (IPM) machine system including an IPM machine including a nominal operating direct current (dc) bus voltage (310), and a controller (110) configured to detect an operating dc bus voltage (Vdc) of the IPM machine and to control the IPM machine based on the nominal operating dc bus voltage (310) and the detected operating dc bus voltage (Vdc).