Electric Motor Rotor Speed Control via Dynamic Magnetic Field Adjustment
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Solution Overview
Problem
Conventional power output apparatuses face challenges in controlling the rotational speed of a rotor during lock control, as the rotor may rotate excessively when the applied torque exceeds the maximum torque that can restrict its rotation, leading to undesirable rotor movement.
Innovation Solution
A power output apparatus with a controller that executes rotation retardation control by adjusting the direction of the stator magnetic field in response to rotor rotation, applying a driving force opposite to the load force to reduce the rotational speed increase, and utilizing predetermined differences in magnetic field directions to manage torque and current effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lock control is executed by fixing the direction of the stator magnetic field to restrict rotor rotation, then the rotor rotation is restricted, but the rotor may still rotate excessively when applied torque exceeds maximum torque
Solution Approach 1:
The controller executes rotation retardation control by detecting rotor rotation during lock control and responding by rotating the stator magnetic field direction in accordance with rotor rotation. This feedback mechanism dynamically adjusts the magnetic field orientation to counteract excessive rotor rotation while maintaining the locking function.
Solution Approach 2:
The system transitions from static lock control (fixed stator magnetic field direction) to dynamic rotation retardation control (rotating stator magnetic field direction that follows rotor rotation). This dynamic adjustment allows the system to adapt to varying torque conditions and prevent excessive rotor rotation more effectively.
2Power
If given current is passed through the d axis at start-time electric angle to apply torque, then the engine can be started, but the rotor may rotate if applied torque exceeds maximum torque of attraction
Solution Approach 1:
During engine starting, the controller monitors rotor position and electric angle, then adjusts the stator magnetic field direction based on detected rotor rotation. This feedback ensures that torque is applied effectively for engine starting while preventing unwanted rotor rotation that would compromise control reliability.
Solution Approach 2:
The system changes the electric angle parameter dynamically during operation. By adjusting the electric angle based on rotor rotation detection, the system optimizes torque application for engine starting while maintaining rotor control within acceptable limits.
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
The solution effectively reduces the rotational speed increase of the rotor during lock control, preventing excessive rotation and minimizing heat generation and thermal issues in the motor and inverter systems.
Implementation Method 1
an electric motor that has a rotor to which the power shaft is connected and a stator that produces a rotating magnetic field, the rotor being rotated by the rotating magnetic field of the stator
Implementation Method 2
the controller executes lock control for controlling the electric motor by fixing a direction of a stator magnetic field as a magnetic field of the stator so as to restrict rotation of the rotor
Implementation Method 3
the controller executes rotation retardation control for controlling the electric motor by rotating the direction of the stator magnetic field in accordance with rotation of the rotor, so that a driving force is applied from the electric motor to the power shaft in a direction opposite to that of a load driving force
Data Source
AI summary
A power output apparatus including a power source, an electric motor and a connecting and disconnecting device, and a method of controlling the power output apparatus, are provided. When load driving force is applied from the power source to a power shaft in a condition where the power shaft and a driveshaft are disconnected from each other by the connecting and disconnecting device, lock control is executed to control the motor by fixing a direction of a magnetic field of a stator so as to restrict rotation of a rotor. When the rotor rotates during execution of the lock control, rotation retardation control is executed to control the motor by rotating the direction of the stator magnetic field in accordance with rotation of the rotor, so that driving force is applied from the motor to the power shaft in a direction opposite to that of the load driving force as driving force applied from the power source to the power shaft.