Synchronous Motor Startup Phase Switching to Prevent Stall

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Solution Overview

Problem

Existing drive systems face challenges in accurately estimating the phase and speed of a synchronous motor during startup, leading to potential stalling or stepping out, especially in low speed ranges.

Innovation Solution

A drive system incorporating a first phase estimation unit, a second phase estimation unit, and a state determination unit to control the synchronous motor by using either the first phase or the second phase based on the motor's operation state, with the first phase corrected using rotor position detection during startup, and a drive control unit to manage the motor's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a hybrid vehicle is equipped with both an internal combustion engine and an electric motor, then the vehicle can operate in both EV mode and engine mode to improve fuel efficiency and reduce emissions, but the system complexity increases due to the need for multiple power sources and control mechanisms

Engineering Contradiction:
Improvefuel efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic switching between EV mode and engine mode based on real-time driving conditions, power demands, and battery state of charge. The control system continuously adjusts the operating mode to optimize fuel efficiency while managing the complexity of the hybrid powertrain through adaptive control strategies

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The internal combustion engine serves multiple functions: it can operate as the primary power source in engine mode, act as a generator to charge the battery, or provide auxiliary power when the electric motor alone is insufficient. This multi-functionality reduces the need for separate dedicated components, thereby managing system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If the vehicle operates in EV mode using the battery-powered electric motor, then emissions are reduced and fuel efficiency improves, but the driving range is limited by the battery's energy capacity

Engineering Contradiction:
ImproveemissionsVSAvoiddriving range
Core Design Contradiction:
Object-affected harmful factorsVSLength of moving object

Solution Approach 1:

The hybrid vehicle alternates between EV mode for short-distance emission-free operation and engine mode for extended range. The system periodically switches modes based on battery charge levels and driving conditions, allowing the vehicle to maintain low emissions during city driving while extending overall range through engine operation during highway or long-distance travel

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The control system dynamically adjusts the state of charge parameters of the battery to optimize the balance between emissions reduction and driving range. By managing battery charge-discharge cycles and adjusting the threshold for switching between EV and engine modes, the system extends effective driving range while maintaining emission benefits

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If the vehicle operates in engine mode using the internal combustion engine, then the driving range is extended, but fuel consumption increases and emissions are generated

Engineering Contradiction:
Improvedriving rangeVSAvoidfuel consumption
Core Design Contradiction:
Length of moving objectVSLoss of energy

Solution Approach 1:

The system performs preliminary charging of the battery during periods of low power demand or regenerative braking events, storing energy that can be used later during high-power requirements. This preliminary energy storage reduces the need for continuous engine operation, thereby extending driving range while minimizing fuel consumption and emissions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system continuously monitors fuel consumption rates, battery state of charge, and driving conditions to dynamically adjust engine operation. By using feedback from sensors and control algorithms, the system optimizes engine efficiency, reduces unnecessary fuel consumption, and extends driving range through intelligent power management

Inventive Principle:
Principle #23Feedback

4Duration of action of moving object

If the battery charge level is high, then the vehicle can operate in EV mode for longer periods, but the system must manage battery discharge to prevent excessive depletion

Engineering Contradiction:
ImproveEV mode durationVSAvoidbattery charge management
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The control system continuously monitors battery state of charge levels and uses feedback control to manage discharge rates. When the battery charge level is high, the system allows extended EV mode operation but automatically transitions to engine mode or reduces electric motor power demand when charge levels approach depletion thresholds, ensuring reliable battery management and preventing excessive discharge

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the duration of EV mode operation based on real-time battery charge levels, driving conditions, and power demands. By continuously adapting the EV mode duration threshold, the system maximizes electric driving opportunities while maintaining battery reliability and preventing excessive depletion

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4425785B1Drive system and control method
Publication Date: 2026.04.08 TMEIC CORP
  • EP4425785B1 patent drawingFigure 1A
  • EP4425785B1 patent drawingFigure 1B~2
  • EP4425785B1 patent drawingFigure 3A~3B

AI summary

A drive system according to an aspect of the embodiment includes a first phase estimation unit, a second phase estimation unit, a state determination unit, and a drive control unit. The first phase estimation unit generates a first phase obtained by estimating a phase of a rotor on the basis of an initial phase at a startup stage of the synchronous motor. The second phase estimation unit generates a second phase obtained by estimating the phase of the rotating rotor on the basis of the operation state of the synchronous motor. The state determination unit determines the operation state of the synchronous motor. The drive control unit controls the driving of the synchronous motor by using any one of the first phase and the second phase according to the determination result of the operation state of the synchronous motor. The first phase estimation unit corrects the first phase by using the detection result of the rotor position detected from the start of the startup procedure of the synchronous motor to the successful startup.